recursal/Fanatic-Fandom huggingface dataset:
Atlantic/2015/02L/Archive/16

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 16

WIKI-HURRICANES FORECAST CENTER

0400AM CDT FRI JUN 19 2015

... BILL'S CIRCULATION PERSISTS ...

SUMMARY OF 9400 AM CDT...0900 UTC...INFORMATION

LOCATION... 36.0N, 93.1W

ABOUT 100MI... 160KM NW OF LITTLE ROCK, ARKANSAS

MAXIMUM SUSTAINED WINDS...15 KT...20 MPH...30 KM/H

MINIMUM BAROMETRIC PRESSURE... 1006 MB...29.71 INCHES

PRESENT MOVEMENT...ENE AT 5 KT...6MPH...9 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 0400 am CDT, the center of Tropical Depression Bill was located at 36.0N, 93.1W, or about 100 miles (160 kilometers) northwest of Little Rock, Arkansas. Maximum sustained winds were 15 knots (20 mph, 30 km/h), with higher gusts. The minimum barometric pressure was 1005 millibars (hPa; 29.68 inHg), and the system was moving east-northeast at 5 knots (6 mph, 9 km/h). Bill is expected to gradually phase into a remnant area of low pressure as it traverses east-northeastward over the next two days.

NEXT ADVISORY

Next complete advisory at 1000 am CDT.

$$

Forecaster Kalassak

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 16

WIKI-HURRICANES FORECAST CENTER

0400AM CDT FRI JUN 19 2015

Radar and satellite representation of Bill are not flattering, the system continues to be very ragged, as would be expected for a tropical system over land. Surface observations maintain that Bill has a closed, although weak, center of circulation. Wind observations support a system with winds of only around 10 to 15 knots. As winds remain weak, most of the impacts associated with Bill will continue to be flooding. Models remain in agreement that the storm will continue moving east-northeast, gradually accelerating as Bill transitions into a remnant low within about 12 to 24 hours and is absorbed by a mid-latitude cyclone in two days or shortly thereafter.

INIT 19/0900Z 36.0N 93.1W 15KT 20MPH

12HR 19/1800Z 36.4N 91.3W 15KT 20MPH ... POST-TROPICAL

24HR 20/0600Z 37.0N 89.6W 15KT 20MPH ... POST-TROPICAL

36HR 20/1800Z 37.7N 88.3W 15KT 20MPH ... POST-TROPICAL

48HR 21/0600Z ... MERGED WITH EXTRATROPICAL CYCLONE

$$

Forecaster Kalassak
Atlantic/2019/01Q/Archive/15

Tropical Storm Iba Discussion Number 15

Wiki-Hurricanes Forecast Center

6:00 AM AST Wed Mar 27 2019

Waxe, wane, rinse, and repeat. The admittedly impressive burst of deep convection that occurred around the time of the previous advisory has begun to fade under the effects of very strong westerly wind shear. Earlier scatterometer data supported an intensity of 35kt, and that is the initial intensity used here. There is nothing new to add to the forecast for Iba. Strong upper-level winds and dry air will likely destroy the storm later today as it moves southeast and then east. Dissipation is expected in about four days.

FORECAST MAX WINDS

INIT 27/0900Z 35 KT 40 MPH

12H 27/1800Z 30 KT 35 MPH

24H 28/0600Z 30 KT 35 MPH...POST-TROP/REMNT LOW

36H 28/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW

48H 29/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW

72H 30/0600Z 20 KT 25 MPH...POST-TROP/REMNT LOW

96H 31/0600Z...DISSIPATED
Atlantic/2019/05L/Archive/56

Dorian has become an extratropical cyclone. Convection has continued to reside within the northern quadrant as a pronounced dry slot wraps around the southern side of the center. A sting jet has been observed in the southeast quadrant, a feature associated with extratropical cyclones, and one that is likely producing strong, damaging winds across Nova Scotia at the current time as the center moves ashore. The extratropical remnants of Dorian are expected to continue moving rapidly northeast, affecting Newfoundland tomorrow morning
before continuing into the far North Atlantic. Dissipation is expected in about 72 hours as the storm is absorbed by a larger non-tropical low.
FORECAST MAX WINDS
INIT 07/2100Z 85 KT 100 MPH
12H 08/0600Z 75 KT 85 MPH...POST-TROP/EXTRATROP
24H 08/1800Z 65 KT 75 MPH...POST-TROP/EXTRATROP
36H 09/0600Z 50 KT 60 MPH...POST-TROP/EXTRATROP
48H 09/1800Z 40 KT 45 MPH...POST-TROP/EXTRATROP
Atlantic/2019/06L/Archive/7

Erin remains pretty similar in satellite presentation compared to the last advisory. The trends since the last advisory have reversed a bit, though. The low-level circulation is now increasingly separated from the organized deep convection. Despite this, Dvorak intensity estimates have increased to T2.5/35kt, which is enough justification to retain Erin as a tropical storm at 35 kt.
Northwesterly wind shear remains around 20 kt. Nonetheless, Erin has a bit of transverse cirrus outflow in its northwest quadrant, showing at least some signs of resilience. Later today, wind shear is expected to decrease, which may provide a bit of a 12-24h window for intensification. For the next 30-36h, sea surface temperatures will remain above 28C and mid-level humidity values hover around an adequate 60%. Once an upper-trough approaches, the favorable environment rapidly deteriorates and the storm will begin extratropical transition at around 36h. The remnant post-tropical cyclone will be absorbed by 72h.
Erin is moving north this morning and this may even shift a little to the west as a result of a mid-level shortwave ridge passing to the northeast of the cyclone. As it passes further to the east and Erin comes under the influence of the approaching low tomorrow it should accelerate to the northeast as it begins extratropical transition. Erin is expected to affect Nova Scotia and Newfoundland as a weakening post-tropical cyclone.
FORECAST MAX WINDS
INIT 28/0300Z 35 KT 40 MPH
12H 28/1200Z 40 KT 40 MPH
24H 29/0000Z 45 KT 50 MPH
36H 29/1200Z 40 KT 45 MPH...POST-TROP/EXTRATROP
48H 30/0000Z 35 KT 40 MPH...POST-TROP/EXTRATROP
Atlantic/2019/02L/Archive/17

Barry's time as a tropical cyclone is drawing to a close. Its center has entered southwestern Arkansas, where weather stations are reporting a minimum pressure that has risen to 1009mb. The definition of the circulation has become increasingly distorted throughout the day today, which is not surprising now that it has been over land for over a day. Winds are light across the region, with peak sustained winds on the order of 25kt; that is the intensity used for this advisory. There is truly nothing new to discuss with Barry. The system has been without organized deep convection since landfall, and even inland convection has subsided. If this continues, Barry will be designated as a remnant low in the morning. Dissipation is likely to occur in about 2 days as it moves north and then northeast into the mid-latitude westerlies.
FORECAST MAX WINDS
INIT 15/0300Z 35 KT 40 MPH...INLAND
12H 15/1200Z 30 KT 35 MPH...POST-TROP/REMNT LOW
24H 16/0000Z 20 KT 30 MPH...POST-TROP/REMNT LOW
36H 16/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2019/10L/Archive/1

Deep convection associated with a wave well east of the Lesser Antilles has sustained and organized well throughout the morning. Dvorak estimates from SAB/TAFB are at T2.0/30 kt supporting formation of a new tropical depression.
The depression is in a favourable environment for strengthening as it moves westward. Shear should remain low and it is passing into warmer SSTs. Occasional dry air entrainment is likely to impinge on the system from pockets subsistence in the tropical Atlantic. Intensity models are fairly bullish with this system, with most of them showing a hurricane within 72 hours. On the other hand, global models are not so keen, with most of them showing minimal development until Ten reaches the subtropics. On the other hand, it's hard to see why the globals are so bearish on the intensity of this system. As such, steady strengthening is expected throughout the entire forecast period.
A strong high is currently pushing this system steadily west-northwest and this movement should continue through day 3 when it approaches the northern edge of the Lesser Antilles. After this, the track forecast gets significantly more uncertain with some global models, such as the ECMWF and GFS, take the system well clear of the Bahamas. Others, such as the HWRF, have it much closer to the Greater Antilles. Consensus is that the storm should remain clear of the Bahamas although it is too far out to give an all clear.

FORECAST MAX WINDS
INIT 17/1500Z 30 KT 35 MPH
12H 18/0000Z 35 KT 40 MPH
24H 18/1200Z 40 KT 45 MPH
36H 19/0000Z 45 KT 50 MPH
48H 19/1200Z 55 KT 65 MPH
72H 20/1200Z 65 KT 75 MPH
96H 21/1200Z 75 KT 85 MPH
Atlantic/2019/05L/Archive/37

The effects of cold water upwelling and the earlier eyewall replacement cycle have taken their toll on Dorian today. Convection is not as deep and winds have come down significantly according to recon. Peak flight-level winds above 115kt and surface winds around 105kt support an initial intensity around 110kt. Despite the degradation in intensity, Dorian remains an extremely dangerous hurricane as it pummels Grand Bahama Island, and the cloud pattern on satellite remains very symmetrical.
The hurricane has barely moved today and remains stationary tonight. However, an approaching upper-level trough should be the impetus for Dorian to begin moving north-northwest before curving and accelerating northeast. The system is still expected to come dangerously close to the eastern coastline of Florida, as well as eastern sections of North Carolina. In fact, the odds of these occurring may be elevated since Dorian has lost intensity a little quicker than anticipated, with low-level flow providing an avenue for the hurricane to wobble more toward the west. As we have been saying for several days now, though, regardless of the exact center track, Dorian remains an extremely dangerous hurricane to the Southeast United States.
Upper-level winds are expected to remain generally light for another 36 to 48 hours or so. Mid-level relative humidity values are beginning to fall, though, and dry air entrainment will become more prevalent as the large circulation of Dorian nears closer to the continental United States. In addition, cold water upwelling should continue to affect the storm, especially in the short term while it remains stationary. Thus, gradual weakening is expected over the coming days. Extratropical transition is finally expected on day 5 as Dorian progresses past the Northeast United States.
FORECAST MAX WINDS
INIT 02/0300Z 110 KT 125 MPH
12H 03/1200Z 105 KT 120 MPH
24H 03/0000Z 105 KT 120 MPH
36H 04/1200Z 100 KT 115 MPH
48H 04/0000Z 95 KT 110 MPH
72H 05/0000Z 85 KT 100 MPH
96H 06/0000Z 75 KT 85 MPH
Atlantic/2019/12L/Archive/5

Karen is back as a tropical storm. Satellite animations show that the system is producing a large mass of largely disorganized convection. This thunderstorm activity is also displaced mainly north of a broad low-level circulation. Nonetheless, both its center and its convection are sufficiently well organized to re-initiate advisories on a tropical cyclone. An Air Force reconnaissance aircraft has found flight-level winds of 41kt and believable SFMR values of 35-36kt, supporting minimal tropical storm strength.
The track forecast philosophy has not changed since Karen was last a tropical cyclone. The system is moving due north and should pass over or just east of Puerto Rico within the next few hours. Once Karen is in the southwestern Atlantic, it may bend more north-northeastward. By days 4 and 5, though, a sharp curve toward the west or west-southwest is expected as high pressure becomes dominant over the Southeast United States.
Unfortunately, Karen's intensity forecast did not become any clearer during its absence. Strong upper-level winds continue to affect the cyclone this morning, although they have relaxed a bit compared to the past 48 hours. Upper-level winds are expected to fall near or below 10kt after 12 hours and remain that low for about 96 hours overall. Those values, combined with ocean temperatures of 28-29C, should be sufficient to promote organization. Mid-level relative humidity values, currently around 70 percent, are expected to continuously decrease to under 50 percent by day 3, and further fall to the mid 30s percent by day 5. This would make Karen prone to occasional bouts of dry air entrainment, especially if combined with an increase in upper-level winds like expected at the tail end of the forecast period. Like we witnessed with Dorian, there are two completely separate camps with regard to intensity. Most global models show dissipation, or continuation as a weak surface low, while the SHIPS/LGEM models foresee a hurricane by day 5. The HWRF also predicts a strong tropical storm around day 3 before weakening thereafter. Given environmental conditions, the solution provided by the HWRF seems most reasonable, and the intensity forecast is closest to that model. This is obviously not a prediction of high confidence.
FORECAST MAX WINDS
INIT 23/1500Z 35 KT 40 MPH
12H 23/0000Z 35 KT 40 MPH
24H 24/1200Z 40 KT 45 MPH
36H 24/0000Z 45 KT 50 MPH
48H 25/1200Z 50 KT 60 MPH
72H 26/1200Z 55 KT 65 MPH
96H 27/1200Z 55 KT 65 MPH
Atlantic/2019/09L/Archive/18

An aircraft reconnaissance plane in the hurricane has confirmed that Humberto has continued to slowly intensify this morning. Most notably, it has found an incredibly increase in hurricane force windfield. The plane recorded maximum flight level winds of 120 kt with max SFMR of 97 kt. Humberto has seen a noticeable lag between FL supported winds and actual measured SFMR winds. Given this, a conservative blend of these estimates give the initial intensity for this advisory, 105 kt.
Humberto is likely at its peak intensity. In the past 6 hours, the convective pattern of the cyclone has begun deteriorating with the clear circular eye being disrupted. Aircraft reconnaissance has found a windfield that indicates baroclynic effects are beginning to be felt, with a massively expanded windfield and maximum winds found well distant from the centre. Despite conditions remaining favourable for the next 12 hours or so, these factors will inhibit the system and slow weakening is expected. After this, wind shear will begin to increase and the system will begin its extratropical transition. Shortly thereafter, fast weakening is expected for the rest of the forecast period until Humberto is no longer tropical.
The hurricane is moving quickly to the east-northeast. It is expected to pass pretty clearly to the north of Bermuda. Yet because of its massively expanded windfield, hurricane conditions are now likely on the island. As it is passing Bermuda today, it is expected to begin turning towards the north due to interaction with a cut-off low. By day 3, it should resume quick east-notheastward motion across the open Atlantic.

FORECAST MAX WINDS
INIT 18/1500Z 105 KT 120 MPH
12H 19/0000Z 100 KT 115 MPH
24H 19/1200Z 85 KT 100 MPH
36H 20/0000Z 70 KT 80 MPH
48H 21/1200Z 65 KT 75 MPH
72H 22/1200Z 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 23/1200Z 55 KT 65 MPH...POST-TROP/EXTRATROP
Atlantic/2019/10L/Archive/3

The tropical depression has intensified into Tropical Storm Jerry. Satellite animations show a massive increase in the coverage and intensity of convection atop the storm's center. A 23z ASCAT-C pass showed maximum sustained winds near 35kt. This is well aligned with satellite intensity estimates of minimal tropical storm force, and so the initial intensity is set at 35kt.
Environmental parameters are generally conducive to intensification in the short term, with wind shear under 10kt, ocean temperatures above 28C, and 700-500mb relative humidity values in the low 50s percent. By 36 hours, however, Jerry is expected to interact with a cut-off low over the central Atlantic. This should cause wind shear values to spike to over 25kt according to the SHIPS file. Thus, despite even warmer ocean waters and higher moisture levels compared to currently, the system is likely to struggle tremendously. Global models have always been bearish on Jerry's intensity moving forward, and this is supported by the 18z HWRF which dropped its earlier solution of a long-tracked major hurricane. Still, a majority of dynamical guidance shows the opportunity for intensification over the coming days, and the SHIPS/LGEM continue to show a mid-grade Category 1 hurricane by day 5. Considering the culmination of data points, I have reduced our intensity forecast from earlier, but further reductions may be likely.
Jerry is moving toward the west-northwest. This trajectory should continue almost unabated for the next 96 hours or so as the cyclone remains on the south side of broad mid-level ridging to its north. By day 5, Jerry should reach the western edge of this ridge and move toward lower heights across the western Atlantic, curving toward the north accordingly. The HWRF has shifted north compared to its 12z run, increasing the likelihood that Jerry remains north of the Caribbean Islands, at least for this cycle.
FORECAST MAX WINDS
INIT 18/0300Z 35 KT 40 MPH
12H 18/1200Z 40 KT 45 MPH
24H 19/0000Z 45 KT 50 MPH
36H 19/1200Z 45 KT 50 MPH
48H 20/0000Z 50 KT 60 MPH
72H 21/0000Z 55 KT 65 MPH
96H 22/0000Z 65 KT 75 MPH
Atlantic/2018/03L/Archive/4

Tropical Storm Chris Discussion Number 4

Wiki-Hurricanes Forecast Center

5:00 AM EDT Sun Jul 8 2018

An Air Force reconnaissance aircraft investigating the tropical depression found that the barometric pressure had decreased substantially, from 1014mb to 1009mb, over the past few hours. In addition, believable flight-level winds of 45kt were found in the deep convection located southeast of the center. This data supports upgrading the depression to Tropical Storm Chris with an initial intensity of 35kt.

Chris is currently located in a collapsed steering regime. It should drift southward over the next 24 to 36 hours as an area of high pressure builds to its north. Thereafter, an approaching shortwave trough is expected to accelerate the storm northeast. Most of the guidance is in good agreement, with the exception of the UKMET which sends Chris into Rhode Island and Massachusetts. This run has been discounted.

The system is currently experiencing moderate northerly wind shear from a nearby cold front. This front is expected to lift out later today, allowing anticyclonic flow to build aloft and upper-level winds to slacken. The broad trough across Canada and New England is expected to give way to a smaller cut-off low northeast of Chris, which should provide a ventilation channel to the east. In 48 to 96 hours, as the approaching trough sends Chris to the northeast, it is expected to be located in the southeastern quadrant of the jet, a notoriously favorable region for upper-level divergence and quick development of low-pressure systems. Water temperatures are more than adequate along the Gulf Stream, and although the surrounding environment is quite dry, the lack of vertical wind shear should keep dry air intrusions to a minimum. Intensity models vary a bit, with 70kt from LGEM representing the lower bound and 948mb from the UKMET representing the upper bound. Model consensus suggests a peak as a mid-grade Category 1 hurricane. However, given the factors mentioned above, I have opted to forecast a stronger storm at 85kt. This may be conservative if Chris makes the most of its interaction with the upper-level trough. Extratropical transition is expected by day 5 as the system moves over waters cooler than 20C.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 35 KT 40 MPH

12H 08/1800Z 45 KT 50 MPH

24H 09/0600Z 55 KT 65 MPH

36H 09/1800Z 65 KT 75 MPH

48H 10/0600Z 75 KT 85 MPH

72H 11/0600Z 85 KT 100 MPH

96H 12/0600Z 75 KT 85 MPH...POST-TROP/EXTRATROP

120H 13/0600Z 60 KT 70 MPH...POST-TROP/EXTRATROP
Atlantic/2019/08L/Archive/11

Gabrielle has failed to produce any convection whatsoever today. In fact, what little thunderstorm activity existed hours ago has dissipated. The initial intensity is reduced to 35kt under the assumption that such a lack of convection has resulted in a decrease in maximum winds. SHIPS currently assesses upper-level winds around 30kt, and these hostile values are likely to persist for another 24 hours or so. This strong shear, combined with environmental dry air, is likely to prevent regeneration into a tropical cyclone during that time. By 36 to 48 hours, however, wind shear is expected to dramatically fall to around 5kt; ocean temperatures will rise to near 29C. Not only should this allow Gabrielle to regenerate into a tropical cyclone, it should provide a window for intensification. The 18z GFS posted its most bullish forecast yet for the cyclone, indicating a strong Category 1 or weak Category 2 hurricane. The HWRF shows a major hurricane. Dynamical guidance is not as strong, but the SHIPS does output 60kt by day 5, also its highest value yet. Thus, for the purposes of this forecast, the intensities at days 3 through 5 have been raised.
Gabrielle is moving toward the northwest, steered by ridges over the Azores and Africa, as well as a mid-level low over the central Atlantic. A turn toward the north is expected to begin a little over 72 hours from now as an upper-level trough approaches from the west. Models remain in great agreement regarding the track forecast.
FORECAST MAX WINDS
INIT 06/0300Z 35 KT 40 MPH...POST-TROP/REMNT LOW
12H 06/1200Z 35 KT 40 MPH...POST-TROP/REMNT LOW
24H 07/0000Z 35 KT 40 MPH...POST-TROP/REMNT LOW
36H 07/1200Z 35 KT 40 MPH...TROPICAL CYCLONE
48H 08/0000Z 45 KT 50 MPH
72H 09/0000Z 55 KT 65 MPH
96H 10/0000Z 65 KT 75 MPH
Atlantic/2019/05L/Archive/6

Dorian's infrared satellite presentation has improved slightly. The storm continues to fire deep convection fueling a small, symmetric central dense overcast, and has good outflow toward the west. In the absence of any new microwave data, it is hard to assess the current state of the formative eyewall seen most recently at 21z. At 06z, Dvorak satellite intensity estimates remain unchanged from six hours prior. With the slight improvement, I have opted to increase the initial intensity to 55 kt.
Dorian is experiencing weak easterly wind shear around 5 kt currently and should continue to do so for about the next 36-48h at least. Given the storm's small size it will be more susceptible to wind shear and its induced dry air intrusions. In a mid-level environment with about 40% relative humidity, these intrusions are pretty much a given, which could intermittently slow intensification at any time. For the next two days or so, the modestly favorable conditions should allow Dorian to steadily intensify. Beyond this point, shear is likely to increase to 10 kt or higher which is expected to affect a storm of this size and may be able to halt its intensification or even induce weakening. Global models continue to suggest weakening and dissipation as the storm enters the eastern Caribbean, and even HWRF has joined this solution for its 00z run. For now, the forecast philosophy remains the same, with weakening beginning as shear increases and the storm interacts with Hispaniola, with some re-strengthening afterwards.
Dorian is tracking west-northwest this morning. It will continue on this track for the rest of today south of a mid-level ridge before this ridge weakens tomorrow, allowing the storm to turn to the northwest. In about 18-24h, Dorian is expected to pass close to Barbados, shortly thereafter passing through the Windward Islands near St. Lucia or St. Vincent and the Grenadines. By day 3 its track will take it near or over Hispaniola and out of the Caribbean.
FORECAST MAX WINDS
INIT 26/0900Z 55 KT 65 MPH
12H 26/1800Z 60 KT 70 MPH
24H 27/0600Z 65 KT 75 MPH...MOVING THROUGH WINDWARD ISLANDS
36H 27/1800Z 70 KT 80 MPH...MOVING THROUGH WINDWARD ISLANDS
48H 28/0600Z 70 KT 80 MPH
72H 29/0600Z 55 KT 65 MPH...INLAND
96H 30/0600Z 40 KT 45 MPH...OVER WATER
Atlantic/2019/07L/Archive/6

Fernand made landfall at 16:15z a little distance north of La Pesca, Mexico, with winds of 40kt. Since that time, the low-level circulation of the storm has progressed inland, still displaced east of convective activity which moved into northern Mexico hours ago. Assuming steady weakening, the initial intensity is set to 30kt and Fernand is now a tropical depression. Now that the system has moved inland, its small low-level circulation should be easily disrupted by the mountainous terrain of northern Mexico, and dissipation is expected about 12 hours from now. Until that time, Fernand is expected to continue moving westward under the influence of mid-level ridging over the Southwest United States.
FORECAST MAX WINDS
INIT 04/2100Z 30 KT 35 MPH...INLAND
Atlantic/2019/13L/Archive/11

Lorenzo is continuing to rapidly intensify throughout today. The eyewall replacement cycle has completed, with only tiny remnants of the old inner eye visible on satellite imagery. The eye has cleared out more since the previous advisory, and the CDO has become much more circular with a powerful ring of -65C eyewall convection. Dvorak estimates from 12Z are T5.5/100 kt, but given trends since then and objective Dvorak analysis near T6.0, the initial intensity is set at 115 kt. The storm has intensified into a very impressive category 4 hurricane.
Conditions remain favourable for continued rapid intensification. However, the storm is rapidly approaching the maximum potential intensity for its location (around 130 kt). The storm is likely to reach 125 kt later today and could begin to stagnate in intensity for that reason. Internal dynamics, like eyewall replacements, could result in unpredictable fluctuations of intensity in the short term. In about 36 hours, shear is expected to increase and this is expected to slightly weaken the system. However, the hurricane should remain quite powerful during this period. By day 5, the storm will pass the 26C SST isotherm and should begin to weaken steadily.
Lorenzo is beginning to turn into the weakness in the ridge to its north. This turn should slowly occur throughout the next few days, eventually leading into a north--northeast track around the periphery of the ridge to its east. Model track consensus remains remarkably high for this forecast.

FORECAST MAX WINDS
INIT 26/1500Z 115 KT 130 MPH
12H 27/0000Z 125 KT 145 MPH
24H 27/1200Z 125 KT 145 MPH
36H 28/0000Z 120 KT 140 MPH
48H 28/1200Z 115 KT 130 MPH
72H 29/1200Z 110 KT 120 MPH
96H 30/1200Z 100 KT 115 MPH
Atlantic/2019/04L/Archive/7

A slight improvement in the focus of Chantal's convection has occurred during the morning hours, with the overall structure taking on a more cyclonic appearance rather than an amorphous one. The center remains displaced to the west or southwest of the deepest convection. With a T2.0/30kt estimate from both subjective agencies and 30kt microwave-derived winds over the last several hours, the current intensity remains at 30 kt.
Chantal is turning increasingly towards the east-southeast and will engage in an anticyclonic loop beginning later today, and this course should take about three days before a trough approaches and accelerates Chantal out of the loop towards the northeast. Overall, conditions generally support little change in strength, and guidance is generally uniform in showing no change or slight weakening throughout the forecast period. The current forecast reflects previous thinking and the environmental parameters. However, given undermodelling of the strength of Chantal's convection, it does appear that models are not responding well to the amount of deep-layer instability. Thus, it would not surprise me if Chantal were to briefly strengthen back to a tropical storm in 24-36 hours, despite most guidance, during a brief window of light shear.
FORECAST MAX WINDS
INIT 22/1500Z 30 KT 35 MPH
12H 23/0000Z 30 KT 35 MPH
24H 23/1200Z 30 KT 35 MPH
36H 24/0000Z 30 KT 35 MPH
48H 24/1200Z 25 KT 30 MPH
72H 25/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW
Atlantic/2015/02L/Archive/4

## Public advisory

TROPICAL STORM BILL ADVISORY NUMBER 4

WIKI-HURRICANES FORECAST CENTER

0400AM CDT TUE JUN 16 2015

... BILL MOVING CLOSER TO LAND ...

SUMMARY OF 0400AM CDT...0900 UTC...INFORMATION

LOCATION... 27.9N 95.2W

ABOUT 100MI... 160KM SSW OF GALVESTON, TEXAS

MAXIMUM SUSTAINED WINDS...50 KT...60 MPH...95 KM/H

MINIMUM BAROMETRIC PRESSURE... 1000 MB...29.53 INCHES

PRESENT MOVEMENT...WNW OR 300 DEGREES... AT 10 KT...11MPH...19 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 0400 am CDT, the center of Tropical Storm Bill was located at 27.9N, 95.2W, or about 100 miles (160 kilometers) south-southwest of Galveston, Texas. Maximum sustained winds were 50 knots (60 mph, 95 km/h), with higher gusts. The minimum barometric pressure was 1000 millibars (hPa; 29.53 inHg), and the system was moving west-northwest at 10 knots (14 mph, 22 km/h). Bill is expected to strengthen into a high-end tropical storm before making landfall near Freeport, Texas in 12 hours, before slowing decaying as it moves northward through East Texas.

NEXT ADVISORY

Next complete advisory at 1000 am CDT.

$$ Forecaster Kalassak

## Discussion

TROPICAL STORM BILL DISCUSSION NUMBER 4

WIKI-HURRICANES FORECAST CENTER

0400 AM CDT TUE JUN 16 2015

Bill's structure continues to improve, although its southeastern appendage has also increased in convective activity as well. The storm now has a relatively decent central dense overcast, and the center of the storm, which is now readily visible on the Galveston radar, appears to be located near the leading northwestern edge. It is significantly more well defined than yesterday. Dvorak classifications of Bill are not picking up on the structure very well and are giving weak returns of T2.0/30kt and T2.5/35kt, which have been disregarded in the face of better data in line with reconaissance flights from yesterday. This results in an initial intensity raised to 50 knots.

The storm has less than twelve hours to intensify before making landfall on the Texas coastline. Bill is not expected to intensify into a hurricane, but with relatively low shear and warm Gulf sea surface temperatures, the storm is expected to intensify in generally favorable conditions during the time it has undisturbed over water. This is not exactly evident via the WHFC intensity forecast, but Bill will likely peak at 55 knots or so in the next six to nine hours before moving inland. Otherwise the intensity forecast follows the same methodology as in the last package. Model consensus is readily available in the track forecast which brings the storm inland over Texas and much further inland where it recurves around a ridge and should become a post-tropical remnant low in around three days. This forecast track will follow model consensus which lies a bit west of the previous forecast.

INIT 16/0900Z 27.9N 95.2W 50KT 60MPH

12HR 17/1800Z 29.0N 96.3W 45KT 55MPH ... INLAND

24HR 17/0600Z 30.7N 97.3W 35KT 40MPH ... INLAND

36HR 18/1800Z 32.5N 97.2W 30KT 35MPH ... INLAND

48HR 18/0600Z 35.0N 96.8W 25KT 30MPH ... INLAND

72HR 19/0600Z 37.2N 94.5W 20KT 25MPH ... REMNANT LOW

$$ Forecaster Kalassak
Atlantic/2019/11L/Archive/2

Tropical Storm Imelda made landfall near Freeport, Texas, around 1:00 pm CDT this afternoon. A weather station just offshore measured peak sustained winds of 43 mph. Taking the observation at face value is worthy enough of a 40kt landfall intensity, and this is especially true once accounting for undersampling. Since that time, the appearance of the storm on radar remains well organized, with reflectivity values higher than 50 dbz near the center. Radar velocities of about 40kt at an elevation of 800ft, coupled with a ship observation of 31kt sustained winds offshore, are sufficient enough evidence to support an initial intensity of 35kt for this advisory. The minimum central pressure is 1006mb based on an observation near the center.
Steady weakening is expected now that Imelda is onshore and moving toward the north. This trajectory should continue for the remainder of the storm's time as a designated tropical cyclone, which is expected to be about 48 to 60 more hours.
FORECAST MAX WINDS
INIT 17/2100Z 35 KT 40 MPH...INLAND
12H 18/0600Z 30 KT 35 MPH...INLAND
24H 18/1800Z 25 KT 30 MPH...INLAND
36H 19/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW
48H 19/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2019/01L/Archive/3

Subtropical Storm Andrea Discussion Number 3

Wiki-Hurricanes Forecast Center

12:00 PM AST Tue Mar 21 2019

... CORRECTION ... ALL RECONNAISSANCE TASKING CANCELLED FOR ANDREA ...

Visible imagery from this morning depict Andrea as having continued subtropical character, with a field of thin low-topped cumuli bands surrounding the center of circulation. Andrea has been largely devoid of deep convection since the morning, and cirrus continues to spread over the system from the upper-low to the south. Given good agreement from both objective CIMSS-ADT and subjective Hebert-Poteat analysis, the intensity for Andrea this advisory has been lowered slightly to a possibly optimistic 35 kt. SSMIS passes at 0956z and 1213z suggested the strongest winds - at least 30 kt in the clear - were located 2-4 degrees east of the center, with the bands near the center possessing 25-30 kt winds within the low resolution context.

Cirrus cloud motions indicate that upper-level winds continue to flow perpendicular to parts of Andrea's wind field, though this has been lightening over the last few hours. As the upper-level low to Andrea's south slides gradually eastward, there is a brief window of favorability later today and tomorrow within the relatively low wind shear field of the upper-trough axis. With cold temperatures of -57F aloft caused by the trough, the thermodynamic parameters are currently supportive of some convective growth. Given the rather loose nature of the subtropical system, however, it is unlikely that this will result in significant strengthening if any, coupled with the marginal degree of favorability and short timeframe of opportunity. Slight weakening is forecast before the vortex is expected to be stretched by the front before eventual frontal absoption.

Andrea is tracking gradually north-northeastwards along the edge of the subtropical ridge to the east. The approach of a fonrtal system and trough are expected to enhance a northeasterly to easterly steering flow beginning tonight. The storm's forecast motion suggests a track near Bermuda around daybreak tomorrow, though impacts are expected to remain limited to light rain and some modestly gusty wnds.

FORECAST MAX WINDS

INIT 21/1500Z 35 KT 40 MPH

12H 22/0000Z 30 KT 35 MPH

24H 22/1200Z 30 KT 35 MPH

36H 23/0000Z...DISSIPATED/ABSORBED BY FRONT
Atlantic/2019/04L/Archive/2

Little has changed with the story of Chantal so far. Infrared satellite imagery continues to show the storm firing convection intermittently off to the north and east of the low-level circulation center as a result of westerly wind shear. Given minimal new information since the last advisory, Chantal's intensity is held at 35 kts.
The forecast track philosophy remains the same as the last advisory. Chantal is positioned in the mid-latitude westerlies where it is expected to track eastward north of a ridge in the north-central Atlantic. This ridge is expected to intensify southwest of the storm, causing a southeasterly turn around 36h. By days 3-5, the storm will be slow moving as it executes an anticyclonic loop west of the Azores under the influence of the ridging weakening in the west and intensifying back to the east.
Chantal is expected to struggle over the next few days. Shear is currently around 20kt, with values expected to increase slightly over the next day and a half or so before dropping dramatically. This will coincide with a gradual decrease and rapid return of warm sea surface temperatures. Chantal will have to hold on through these marginal conditions to make it to the more favorable conditions expected on day 2 and beyond. Dry air, on the other hand, is expected to be a persistent issue for the storm. With values currently around 40% and with a drop forecast in the short term, conditions will remain marginal for the storm until day 2. Provided Chantal makes it there, it may have a window for some slight intensification on day 3, but low humidity values will remain an issue throughout the forecast period, hampering most chances at significant intensification.
FORECAST MAX WINDS
INIT 21/0900Z 35 KT 40 MPH
12H 21/1800Z 35 KT 40 MPH
24H 22/0600Z 30 KT 35 MPH
36H 22/1800Z 30 KT 35 MPH
48H 23/0600Z 30 KT 35 MPH
72H 24/0600Z 35 KT 40 MPH
96H 25/0600Z 35 KT 40 MPH
Atlantic/2019/02L/Archive/15

Barry has become progressively diffuse this morning as it continues to track generally northward, with surface observations suggesting that the broadening center is roughly 20 miles northwest of Natchitoches. The strongest convection and winds remain displaced well southeast of the center, localized in a band stretching from Alexandria to New Iberia and transitioning to a large amorphous region over the Gulf of Mexico south of Galveston. The highest winds from land obversations are only about 15 kt. The highest directly sampled marine winds at both surface and elevated stations was 26 kt. However, doppler velocities from the radar site in Lake Charles show winds aloft of 45-49 kt, and the areas where the strongest winds are located are not well-sampled. Thus, the intensity for this advisory has been reduced slightly to 35 kt. These gale-force winds are all localized offshore.
With steering currents still marginal, Barry is expected to largely remain in Louisiana or perhaps eastern Texas for most of the today. The weakening storm's present motion is still slightly west of north, but should slowly veer north and later northeast over the next two days as it traverses the edges of a low-level ridge over Florida. Without much semblance of organized convective activity near its center, Barry is expected to degenerate into a remnant low in roughly two days with dissipation in three.

FORECAST MAX WINDS
INIT 14/1500Z 35 KT 40 MPH...INLAND
12H 15/0000Z 30 KT 35 MPH...INLAND
24H 15/1200Z 25 KT 30 MPH...INLAND
36H 16/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 16/1200Z 15 KT 20 MPH...POST-TROP/REMNT LOW
Atlantic/2019/05L/Archive/19

The convective pattern of Hurricane Dorian has improved since the last advisory, with a more symmetrical central dense overcast and occasional glimpses of an eye on infrared imagery. An Air Force reconnaissance plane investigating the storm found that the central pressure has fallen back to 986mb, with surface winds near 75kt. That is the intensity used for this advisory.
Dorian continues to be affected by ever so slight southwesterly shear, just as models predicted. This shear should begin to recede over the next few hours, opening the door for intensification. Ocean temperatures are expected to remain more than sufficient, between 28-30C, and 700-500mb relative humidity values should steady climb to near 70 percent before landfall. This should allow Dorian to become a major hurricane and further strengthen to a Category 4 before landfall in four days or so.
Recon fixes indicate Dorian is moving toward the northwest, and this motion should continue for another 36 hours or so. After that, high pressure should develop off the Southeast United States and force Dorian to curve westward. There is a bit of a windshield wiper effect going on in model data these past few days. Last night, models had converged on a westward track toward the Gulf of Mexico, ruling out the possibility of a curve northward. This morning, a significant number of EPS members suggest that possibility once again. Dynamical guidance is pretty squarely set in central Florida, and so I continue to forecast a landfall in that general vicinity about four days from now.
FORECAST MAX WINDS
INIT 29/1500Z 75 KT 85 MPH
12H 30/0000Z 80 KT 90 MPH
24H 30/1200Z 85 KT 100 MPH
36H 31/0000Z 90 KT 105 MPH
48H 31/1200Z 100 KT 115 MPH
72H 01/1200Z 110 KT 125 MPH
96H 02/1200Z 115 KT 130 MPH
Atlantic/2019/09L/Archive/13

Humberto's large presence has expanded further as its central dense overcast seems to have expanded on infrared satellite imagery over the past few hours. An AMSR2 microwave pass from 0700z shows that the eyewall replacement cycle Humberto went through today is finishing up. The recent large dry slot near the center and the current restructuring of the eye on infrared satellite is likely a result of the tail end of the cycle. For now, the intensity of the hurricane remains 75 kt, but intensification is likely in the process of resuming. How much of that has occurred will likely be seen with the recon flight en route to the storm right now.
Environmental conditions are expected to remain favorable for the next two days with warm sea surface temperatures and strong upper forcing for ascent. A major hurricane is still expected on day 2. Beyond that, sea surface temperatures are expected to decrease and wind shear is expected to steeply incline, resulting in weakening. Interaction with an upper trough will likely cause transition into an extratropical cyclone by day 5.
Humberto is moving just north of east this morning. It should continue in this direction or more east-northeasterly for the next two days before a mid-level trough becomes cut-off, causing the hurricane to turn north and interact with it. By day 4, the hurricane's course should return toward the northeast as it re-enters the mid-latitude flow.
FORECAST MAX WINDS
INIT 17/0900Z 75 KT 85 MPH
12H 17/1800Z 90 KT 105 MPH
24H 18/0600Z 100 KT 115 MPH
36H 18/1800Z 105 KT 120 MPH
48H 19/0600Z 95 KT 110 MPH
72H 20/0600Z 85 KT 100 MPH
96H 21/0600Z 70 KT 80 MPH
Atlantic/2019/02L/Archive/9

Barry has organized substantially this evening. Visible satellite imagery before the sun set revealed a more consolidated low-level circulation, largely free of mesovortices, that had migrated to the northern edge of preexisting convection. Since that time, deep thunderstorm activity has blossomed near the position of the center, with frequent lightning and tops pushing -90C. Unfortunately, the Air Force reconnaissance aircraft investigating the storm stopped reporting as it entered the ever-important northeast quadrant. However, data it recorded prior to that time supported an initial intensity of at least 55kt, and that is the strength used in this advisory. It would not be surprising if this was conservative.
Water vapor imagery shows a tale of two different wind layers. Upper-level outflow has been expanding northward from Barry's convection for the past 6 hours, an indication that 200mb wind shear has decreased to more conducive levels. However, that same imagery shows mid-level shear increasing. The end result is a storm that has been able to produce convection over the center now, but one that continues to lack a fruitful northern semicircle. Nevertheless, combined with very warm ocean temperatures and the mixing out of earlier continental dry air, these factors point to an environment that is conducive for continued strengthening up to landfall. An outside factor potentially contributing to an increase in strength will be Barry's interaction with the coastline of Louisiana, with the frictional effects of the land helping to amplify its circulation and generate deeper convection. The new forecast explicitly calls for Barry to become a Category 1 hurricane again. Slow weakening is expected as Barry moves across southern Louisiana, with more rapid weakening thereafter. The storm should degenerate to a remnant low about 48 hours from now. Dissipation remains set at day 5.
Barry is crawling toward the west-northwest this evening but should turn northwest into a weakness between two ridges over the United States. This trajectory will bring the system ashore near Marsh Island as previous forecasts have expected. After 24 hours, the cyclone should curve north and then northeast as it rounds the easternmost ridge and becomes embedded in mid-latitude westerlies.
FORECAST MAX WINDS
INIT 13/0300Z 55 KT 65 MPH
12H 13/1200Z 65 KT 75 MPH...NEAR LANDFALL
24H 14/0000Z 45 KT 50 MPH...INLAND
36H 14/1200Z 30 KT 35 MPH...INLAND
48H 15/0000Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 16/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 17/0000Z 15 KT 20 MPH...POST-TROP/REMNT LOW
Atlantic/2019/05L/Archive/43

Dorian is better organized this morning. Deep convection is rotating around the hurricane's large eye, mixing out dry air and leading to organization of the inner core. An Air Force reconnaissance plane just passed through the eye, measuring a sharper pressure gradient than before and a pressure around 965mb. Flight-level winds have increased to 100kt, supporting an initial intensity of 90kt.
There is some opportunity for Dorian to gain strength this afternoon as it moves across the Gulf Stream and while wind shear remains low. Beginning tomorrow, the culmination of wind shear, dry air, and land interaction should cause Dorian to weaken. Extratropical transition is anticipated between days 3 and 4.
Dorian is moving north-northwest this morning. This motion is expected to continue for the next several hours as an upper-level trough begins to erode high pressure off the Southeast United States. A northwest motion should give way to a north and then northeast trajectory beginning tonight. This should bring the eye of Dorian extremely close to the coastline of South Carolina and then across the coastline of North Carolina. By day 4, the extratropical remnants of Dorian should affect Nova Scotia and Newfoundland.
FORECAST MAX WINDS
INIT 04/1500Z 90 KT 105 MPH
12H 05/0000Z 95 KT 110 MPH
24H 05/1200Z 90 KT 105 MPH
36H 06/0000Z 85 KT 100 MPH
48H 06/1200Z 80 KT 90 MPH
72H 07/1200Z 70 KT 80 MPH
96H 08/1200Z 60 KT 70 MPH...POST-TROP/EXTRATROP
Atlantic/2019/06L/Archive/12

Conventional satellite imagery and ASCAT data indicate that the circulation of Erin merged with a frontal boundary between 9z and 15z, and the system is now classified as an extratropical low accordingly. The low continues to accelerate north-northeast and should progress across Nova Scotia within the next 24 hours. After that time, it should be absorbed by an even larger extratropical low over eastern Canada.
FORECAST MAX WINDS
INIT 29/1500Z 30 KT 35 MPH...POST-TROP/EXTRATROP
12H 29/0000Z 35 KT 40 MPH...POST-TROP/EXTRATROP
24H 30/1200Z 35 KT 40 MPH...POST-TROP/EXTRATROP
Atlantic/2015/02L/Archive/22

## Public advisory

POST-TROPICAL CYCLONE BILL ADVISORY NUMBER 22

WIKI-HURRICANES FORECAST CENTER

400PM CDT SAT JUN 20 2015

... BILL FINALLY GOES POST-TROPICAL ...

SUMMARY OF 400PM CDT...2100 UTC...INFORMATION

LOCATION... 38.5N, 82.1W

ABOUT 25MI... 40KM WNW OF CHARLESTON, WEST VIRGINIA

MAXIMUM SUSTAINED WINDS...15 KT...20 MPH...30 KM/H

MINIMUM BAROMETRIC PRESSURE... 1005 MB...29.68 INCHES

PRESENT MOVEMENT...ENE AT 24 KT...28MPH...44 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 400 pm CDT, the center of Post-Tropical Cyclone Bill was located at 38.5N, 82.1W, or about 25 miles (40 kilometers) west-northwest of Charleston, West Virginia. Maximum sustained winds were 15 knots (20 mph, 30 km/h), with higher gusts. The minimum barometric pressure was 1005 millibars (hPa; 29.68 inHg), and the system was moving east-northeast at 24 knots (28 mph, 44 km/h). Bill is expected to slowly weaken as it accelerates east-northeastward before eventually merging with a frontal system.

NEXT ADVISORY

This is the last advisory on Bill.

$$

Forecaster TheAustinMan

## Discussion

POST-TROPICAL CYCLONE BILL DISCUSSION NUMBER 22

WIKI-HURRICANES FORECAST CENTER

400PM CDT SAT JUN 20 2015

After considerable time over land and unusual persistence, analyses show that the core of Bill has finally transitioned from warm-core to cold-core, meaning that Bill has completed a transition from a tropical to a post-tropical cyclone. Surface observations also show that Bill's circulation is also becoming less defined, though strong surface winds are still present. The convective structure of Bill remains intact, with convection still wrapping
about the center. Despite Bill's designation at this time, Bill will remain a flood threat to the Mid-Atlantic states before it departs the continental United States later on.

INIT 20/2100Z 38.5N 82.1W 15KT 20MPH ... REMNANT LOW

12HR 21/0600Z 40.2N 77.0W 15KT 20MPH ... REMNANT LOW

24HR 21/1800Z 41.4N 71.4W 20KT 25MPH ... REMNANT LOW

36HR 22/0600Z ... MERGED WITH FRONTAL SYSTEM

$$

Forecaster TheAustinMan