recursal/Fanatic-Fandom huggingface dataset:
Atlantic/2018/03L/Archive/15

Hurricane Chris Discussion Number 15

Wiki-Hurricanes Forecast Center

5:00 PM EDT Wed Jul 11 2018

Chris is showing mixed signs of strength this afternoon. On one hand, the eye has become more distinct and symmetrical compared to this morning. On the other hand, convection has weakened in the south and east quadrants of the hurricane, likely due to some dry air intrusion and cooler ocean temperatures. Satellite intensity estimates from SAB and TAFB are a unanimous T4.5/77kt, but T5.2/94.8kt from UW-CIMSS ADT and 89kt from SATCON. A blend of these values supports lowering the initial intensity slightly to 85kt.

The intensity forecast for the next few hours is complicated. After losing some organization this morning, the interaction between Chris and the upper-level trough has allowed it to stabilize. Dry air remains a transient feature at best, while ocean temperatures are actually expected to decrease to 28-29C around sunset before Chris crosses the sharp Gulf Stream gradient. Theoretically, there is a small window that exists for Chris to intensify before that point. This won't be represented in our forecast, but it would not be surprising. Entering tomorrow, Chris is expected to quickly make the transition to an extratropical cyclone as it more wholly interacts with the upper-level trough and passes over waters below 20C. On a consistent northeast trajectory, Chris should pass just southeast of Newfoundland between 24 and 36 hours, delivering tropical storm-force winds and heavy rainfall. A bend more toward the east is expected by day 2 before dissipation on day 3.

FORECAST POSITIONS AND MAX WINDS

INIT 11/2100Z 85 KT 100 MPH

12H 12/0600Z 80 KT 90 MPH

24H 12/1800Z 70 KT 80 MPH...POST-TROP/EXTRATROP

36H 13/0600Z 55 KT 65 MPH...POST-TROP/EXTRATROP

48H 13/1800Z 40 KT 45 MPH...POST-TROP/EXTRATROP

72H 14/1800Z...DISSIPATED
Atlantic/2019/01Q/Archive/21

Post-Tropical Cyclone Iba Discussion Number 21

Wiki-Hurricanes Forecast Center

06:00 PM AST Fri Mar 28 2019
Iba has finally succumbed to the bone-dry airmass and exceptional shear field it finds itself in this afternoon. Although some semblance of a low-level circulation exists, the system has not produced any sort of convection that would be considered organized for the entirety of the day, and the vortex continues to become increasingly ill-defined. In lieu of any recent scatterometer data near the center, the intensity has been decreased slightly for this advisory to 30 kt, and with the lack of organized storm activity Iba has been downgraded to a post-tropical system. The remnant circulation may drift east to northeast over the next day or so before dissipating.

FORECAST MAX WINDS

INIT 28/2100Z 30 KT 35 MPH

12H 29/0600Z 30 KT 35 MPH...POST-TROP/REMNT LOW

24H 29/1800Z...DISSIPATED
Atlantic/2019/05L/Archive/2

The depression in the central Atlantic has strengthened into Tropical Storm Dorian. Deep convection has formed over the center this evening, yielding a low-level cyan ring on microwave imagery that may portray a rapid increase in strength if organization continues unabated. Upper-level outflow has also continued to expand westward, though it is restricted to the east. Satellite intensity estimates have increased across the board since the last advisory, with SAB at T2.0/30kt, UW-CIMSS ADT at T2.3/33kt, and TAFB at T2.5/35kt. These numbers plus the increase in organization since earlier support an initial intensity of at least 35kt.
Upper-level winds should be in the process of decreasing, and wind shear is expected to remain at favorable levels for the next 60 to 72 hours, up until the tropical cyclone interacts with a cut-off low over the central Caribbean. Ocean temperatures, around 28C currently, should increase to 29-30C through the next 5 days. The only limiting factor is expected to be dry 700-500mb relative humidity values in the neighborhood of 40-50 percent for the next 4 days or so. Model guidance remains split, with global models showing little intensification in the short term followed by dissipation in the eastern Caribbean; hurricane models, by contrast, paint a much different picture. The SHIPS and LGEM depict a Category 1 hurricane, whereas the HWRF goes even further with a cyclone of Category 3 intensity. It is worth pointing out that, while SHIPS rapid intensification values are not extraordinarily high, they are significantly elevated compared to climatological means. A rapid intensification episode would be supported by Dorian's current presentation on microwave imagery, provided dry air intrusions do not disrupt development. For now, the intensity forecast has been edged up over the next 4 days, though this a low confidence move. Swifter weakening is expected on day 5 as Dorian strikes Hispaniola or Puerto Rico.
Dorian is moving steadily westward and should remain on a west or west-northwest heading for the next 3 days as mid-level ridging remains stout northeast of the Leeward Islands. After the system enters the Caribbean, it should move more toward the northwest, coincident with a weakening and eastern shift of the aforementioned high pressure. On the current forecast track, Dorian should move near or over Dominica and continue toward eastern Hispaniola.
FORECAST MAX WINDS
INIT 25/0300Z 35 KT 40 MPH
12H 25/1200Z 45 KT 50 MPH
24H 26/0000Z 50 KT 60 MPH
36H 26/1200Z 55 KT 65 MPH
48H 27/0000Z 65 KT 75 MPH
72H 28/0000Z 70 KT 80 MPH...MOVING THROUGH LEEWARD ISLANDS
96H 29/0000Z 75 KT 85 MPH
Atlantic/2018/03L/Archive/6

Tropical Storm Chris Discussion Number 6

Wiki-Hurricanes Forecast Center

11:00 PM EDT Sun Jul 8 2018

Chris has continued to become better organized over the past several hours. An Air Force reconnaissance aircraft investigating the system earlier found that the low-level circulation had reformed east and aligned with the mid-level center. The satellite presentation has continued to improve, with a dry slot helping the transition the scene type to a ragged eye. A second plane investigating Chris currently has found peak flight-level winds of 57kt, supporting an initial intensity of 50kt.

Nothing has changed in terms of the track forecast. Chris is located in a collapsed steering regime, and it should meander for the next 36 hours. On Tuesday, an upper-level trough diving southward from Canada should provide an avenue for the storm to accelerate northeast toward Newfoundland.

The front responsible for shearing Chris over the past few days is becoming more diffuse, allowing for anticylonic flow to expand. This low shear environment, coupled with the warm waters of the Gulf Stream, should allow for steady strengthening over the next few days. There are two potential caveats, one being that intermittent dry air intrusions could slow the intensification rate. The second is that the upper-level pattern is very favorable, and rapid intensification is not out of the question once Chris establishes a healthy inner core, especially on Wednesday when its interaction with the upper-level trough will be most beneficial. The intensity forecast has been left generally the same for this advisory, but it may be conservative if models such as the ECMWF are correct.

FORECAST POSITIONS AND MAX WINDS

INIT 09/0300Z 50 KT 60 MPH

12H 09/1200Z 60 KT 70 MPH

24H 10/0000Z 70 KT 80 MPH

36H 10/1200Z 80 KT 90 MPH

48H 11/0000Z 90 KT 105 MPH

72H 12/0000Z 85 KT 100 MPH

96H 13/0000Z 60 KT 70 MPH...POST-TROP/EXTRATROP

120H 14/0000Z 40 KT 45 MPH...POST-TROP/EXTRATROP
Atlantic/2019/10L/Archive/22

Jerry no longer meets the qualifications of a tropical cyclone so it has degenerated into a remnant low. The storm has failed to produce any convection anywhere near the center since the previous advisory. Jerry currently sits over marginal sea surface temperatures and exists within an environment of strong shear and dry air which is forecast to remain in place. Little convection is expected to be able to form in this environment and simulated infrared model guidance from GFS and HWRF agree. This will result in continued weakening as a remnant until dissipation.
The remnants of Jerry are moving slowly northward today, although they are forecast to accelerate east-northeast with a passing upper-level trough. Beyond day 3, models are coming into increasing agreement that a passing mid-latitude shortwave ridge will push Jerry's remnants south and eventually southwest by day 5, when the remnant low is expected to dissipate.
FORECAST MAX WINDS
INIT 24/2100Z 45 KT 50 MPH...POST-TROP/REMNT LOW
12H 25/0600Z 40 KT 45 MPH...POST-TROP/REMNT LOW
24H 25/1800Z 35 KT 40 MPH...POST-TROP/REMNT LOW
36H 26/0600Z 30 KT 35 MPH...POST-TROP/REMNT LOW
48H 26/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 27/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 28/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2019/10L/Archive/8

In a fairly surprising move, Jerry has intensified significantly today. The Air Force reconnaissance aircraft that was investigating the cyclone a few hours ago found maximum flight-level winds of 97kt, with peak SFMR winds lower around 70kt. The minimum barometric pressure over the course of the mission fell from 988mb to 982mb as confirmed by center dropsondes. On satellite, Jerry has not had the typical appearance of a quickly-intensifying hurricane for most of today, with deep convection focused asymmetrically near the center and a lack of spiral banding in the western semicircle. However, over the past 2 hours, the storm's presentation has become much better organized, with rounder convection and the formation of a ragged eye on visible imagery. Satellite intensity estimates are unchanged since earlier, but these are little use right now considering what recon measured earlier. Given the improvement in organization, the initial intensity is raised to 80kt; this may be conservative given the flight-level wind measurements several hours ago.
Jerry is currently experiencing moderate wind shear on the order of 15kt. This shear, unfavorable on its own, is helping to inject extremely dry air into the storm circulation. However, this dry air is not yet having an impact on the inner core. Upper-level winds are not forecast to further increase for approximately another 12 hours, so the opportunity exists for further intensification this evening and overnight. Beyond that time, wind shear on the order of 25-30kt should invoke rapid weakening of the storm, especially given the magnitude of dry air around. The statistical guidance does not indicate much, if any, weakening over the next few days, but this has been discounted for the reasons discussed above. The updated intensity forecast has been reconfigured and is much higher in the near term but much lower on days 2 through 4. Redevelopment is expected on day 5 as Jerry curves northward into a lower wind shear environment.
A massive mid-level ridge positioned southwest of the Azores and east of Bermuda is steering the hurricane toward the west-northwest. Model guidance is in fantastic agreement that this west-northwest course will continue for the next 48 hours or so. Beyond that time, as Jerry reaches the western periphery of the ridge and begins to interact with an upper-level trough across the western Atlantic, the cyclone should curve north and north-northeast. This recurvature should position Jerry very close to the island of Bermuda about 5 days from now.
FORECAST MAX WINDS
INIT 19/2100Z 80 KT 90 MPH
12H 20/0600Z 90 KT 105 MPH
24H 20/1800Z 75 KT 85 MPH
36H 21/0600Z 60 KT 70 MPH
48H 21/1800Z 45 KT 50 MPH
72H 22/1800Z 50 KT 60 MPH
96H 23/1800Z 60 KT 70 MPH
Atlantic/2019/09L/Archive/11

Humberto has grown into a large and well-organized hurricane, possessing a well-defined eye that has become more pronounced in the last few hours. A channel of more subsident air and warmer cloud tops is present at the interface between the storm's northern rainshield and the central dense overcast, but trends in the convective organization of the eyewall suggest the hurricane is gradually sealing up this primary failure point. Outflow is superb in all quadrants, which is unsurprising given the clean airflow offered by the strong polar jet from Humberto to the northern Atlantic. Overall, the storm has taken on a classical appearance typical of slow-moving storms ventilated by a zonally-oriented trough. Based on data from a reconnaissance plane currently investigating Humberto, the current intensity remains at 75 kt, though its central pressure has been falling substantially.
We're now near the tail-end of more conventional low-latitude intensification processes as Humberto begins to entrench itself more within the nearby upper-level jet, which will facilitate robust divergence aloft. This transition of intensification modes will likely take place tonight into tomorrow morning. All the while, sea surface temperatures are expected to remain between 27-28C for roughly the next three days. Humberto is in prime opportunity to ramp up quite quickly to a very large major hurricane within the next three days. Afterwards, the setup gets complicated as Humberto effectively wedges itself into the trough roughly 3-4 days from now, probably becoming a hybrid cyclone somewhere within the blurred boundary between a tropical and subtropical cyclone. Humberto will likely weaken somewhat in this chaotic exchange before transitioning into a strong extratropical cyclone at the end of the forecast period. If Humberto is able to foment for a bit within a more quieter upper-level region in four days, this extratropical transition may be delayed.
With the trough now grasping Humberto, the hurricane is now on an east-northeasterly path as confirmed by satellite and reconnaissance fixes. This results in a short-term high-consensus track about 100 miles northwest of Bermuda in 2-3 days. By sheer size of Humberto, this implies a high likelihood of gale-force winds and a probable likelihood of 50kt winds for the territory. Afterwards, interaction with a southward-tracking upper-level low detached from its parent trough will result in a brief swing towards the north or north-northwest in four days followed by a return to an accelerated east-northeast or northeast motion as Humberto reconnects with the polar jet.

FORECAST MAX WINDS
INIT 16/2100Z 75 KT 85 MPH
12H 17/0600Z 85 KT 100 MPH
24H 17/1800Z 100 KT 115 MPH
36H 18/0600Z 105 KT 120 MPH
48H 18/1800Z 105 KT 120 MPH
72H 19/1800Z 95 KT 110 MPH
96H 20/1800Z 70 KT 80 MPH
Atlantic/2015/02L/Archive/7

## Public advisory

TROPICAL STORM BILL ADVISORY NUMBER 7

WIKI-HURRICANES FORECAST CENTER

1000PM CDT TUE JUN 16 2015

SUMMARY OF 1000PM CDT...0300 UTC...INFORMATION

LOCATION... 29.5N 96.9W

ABOUT 70MI... 115KM SE OF AUSTIN, TEXAS

MAXIMUM SUSTAINED WINDS...35 KT...40 MPH...65 KM/H

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

PRESENT MOVEMENT...NNW AT 10 KT...12MPH...19 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 1000 pm CDT, the center of Tropical Storm Bill was located at 29.5N, 96.9W, or about 70 miles (115 km) southeast of Austin, Texas. Maximum sustained winds were 35 knots (40 mph, 65 km/h), with higher gusts. The minimum barometric pressure was 1000 millibars (hPa; 29.53 inHg), and the system was moving towards the north-northwest at 10 knots (12 mph, 19 km/h). Bill is expected to curve around a subtropical ridge and slowly weaken over the next two days, which will result in the system tracking near the Dallas-Forth Worth metropolitan area before curving eastward towards the Ozarks.

NEXT ADVISORY

Next complete advisory at 400 am CDT.

$$

Forecaster TheAustinMan

## Discussion

TROPICAL STORM BILL DISCUSSION NUMBER 7

WIKI-HURRICANES FORECAST CENTER

1000PM CDT TUE JUN 16 2015

Tropical Storm Bill has exhibited unusual development over the past six hours, with a large convective burst over the center coupled with significantly cooling cloud tops despite now moving over land. These changes have not been as significant in radar images out of Houston and New Braunfels, Texas, but they point to the probability of slow weakening as Bill moves further inland. The current intensity has been lowered slightly to 35 knots to balance between the recent burst of convective activity and comparatively unimpressive ground observations. Bill has developed a feeder rainband offshore east of Corpus Christi, and this will play a large role in determining where the heaviest rainfalls associated with Bill could occur.

Models are in consensus as to what the track of Bill will shape up to be, and the current WHFC forecast track follows the general model thinking. Bill is expected to move on a north-northwesterly into the Dallas-Fort Worth metroplex before beginning to make a recurve northeastward about the subtropical ridge which has steered Bill throughout its existence. This will bring Bill or its remnants across the Ozarks and into the Ohio River Valley in several days. As for the intensity forecast, models are generally showing slow deterioration of Bill's intensity, with some models insisting upon strengthening over the saturated soils of Texas and Oklahoma. For this advisory, a slow weakening trend has been used to direct the demise of Bill over the South Central United States.

INIT 17/0300Z 29.5N 96.9W 35KT 40MPH

12HR 17/1200Z 31.2N 97.2W 30KT 35MPH

24HR 18/0000Z 33.2N 96.8W 25KT 30MPH ... REMNANT LOW

36HR 18/1200Z 34.8N 96.0W 25KT 30MPH ... REMNANT LOW

48HR 19/0000Z 36.5N 94.0W 20KT 25MPH ... REMNANT LOW

72HR 20/0000Z 38.1N 89.1W 15KT 20MPH ... REMNANT LOW

96HR 21/0000Z 39.4N 83.5W 20KT 25MPH ... REMNANT LOW

120HR 22/0000Z ... MERGED WITH EXTRATROPICAL CYCLONE

$$

Forecaster TheAustinMan
Atlantic/2019/05L/Archive/40

Dorian has become a little better organized this afternoon. The eye is more organized on both radar and conventional satellite imagery, and the overall cloud pattern remains symmetrical. An Air Force reconnaissance aircraft just arrived in the storm, measuring peak flight-level winds of 100kt in the southeast eyewall. While this would support an initial intensity of 90kt, I prefer to keep Dorian's strength a little higher until the aircraft measures all quadrants. The latest pressure is 957mb according to the dropsonde, which is actually down a millibar from the previous flight.
Upper-level winds will remain light for the next 36 hours and ocean temperatures are actually on the increase as Dorian moves away from its upwelled waters. Thus, little change in strength is expected during that time despite a decrease in 700-500mb relative humidity values. It would not be too surprising if some re-intensification actually occurred as indicated by some models such as the ECMWF. Beyond that time, upper-level winds should affect the cyclone and more efficiently inject dry air into the circulation, promoting weakening. Land interaction should further weaken Dorian on day 3. By days 4 and 5, the culmination of cold water and interaction with the mid-latitude westerlies should cause gradual extratropical transition.
Dorian is finally, finally moving northwestward. A curve toward the north is expected after tomorrow morning as an upper-level trough erodes high pressure off the Southeast United States. By Thursday, Dorian should accelerate northeastward toward the coastline of eastern North Carolina, where a landfall looks as likely as ever. Dorian should continue past the Northeast United States and then into Nova Scotia and Newfoundland as a potent extratropical low.
FORECAST MAX WINDS
INIT 03/2100Z 95 KT 110 MPH
12H 04/0600Z 95 KT 110 MPH
24H 04/1800Z 95 KT 110 MPH
36H 05/0600Z 90 KT 105 MPH
48H 05/1800Z 85 KT 100 MPH
72H 06/1800Z 75 KT 85 MPH
96H 07/1800Z 65 KT 75 MPH
Atlantic/2019/08L/Archive/2

The cloud pattern of Tropical Depression Eight has become a little better organized this afternoon, with deep convection bubbling near the center. The low-level circulation itself has also become more symmetrical though still broad. There have been no additional scatterometer passes since earlier, but given the uptick in organization, I have elected to raise the initial intensity to 30kt.
In the short term, Eight is embedded within an environment of high moisture content and low wind shear but cool ocean temperatures. By the middle of the forecast period, the air is expected to become extremely dry and wind shear is expected to skyrocket, but ocean temperatures will be warm. By day 5, provided the tropical cyclone survives until that time, environmental conditions are finally expected to become conducive for strengthening. Like I said in the previous advisory, however, I would prefer to see more definitive signs that Eight has a long life ahead of it before biting on the opportunity for development several days from now. The GFS and ECMWF do suggest the potential for more organization over the next 2 days than previous runs, so I have slightly increased the intensity during that time. The forecast is generally unchanged otherwise.
The culmination of high pressure over Africa, high pressure over the Azores, and a cut-off low over the central Atlantic should keep Tropical Depression Eight on a due northwest course over the next 5 days, a solution that most models are in good agreement about.
FORECAST MAX WINDS
INIT 03/1500Z 30 KT 35 MPH
12H 04/0000Z 30 KT 35 MPH
24H 04/1200Z 35 KT 40 MPH
36H 05/0000Z 40 KT 45 MPH
48H 05/1200Z 35 KT 40 MPH
72H 06/1200Z 35 KT 40 MPH
96H 07/1200Z 30 KT 35 MPH
Atlantic/2019/05L/Archive/52

Shockingly, Dorian has intensified into a Category 2 hurricane this evening. The large eye has remained clear and symmetric, while convection within the central dense overcast has deepened. Notably, thunderstorm activity is most intense upshear of the center, which strongly suggests intensification is indeed occurring this afternoon. Recent satellite intensity estimates are T4.5/77kt from TAFB, T5.0/90kt from SAB, T5.4/100kt from UW-CIMSS ADT, and 101kt from SATCON. A blend of these values supports raising the initial intensity to 90kt.
Shear output from the SHIPS file suggested that upper-level winds would become hostile over a day ago now. Instead, the interaction between the upper-level trough and Hurricane Dorian has been a favorable one as evidenced by the excellent poleward outflow channel on conventional satellite imagery. Regardless, the hurricane only has about 6 to 9 hours left over ocean temperatures greater than 26C; by this time tomorrow, they should be around 17C. In addition, continued interaction with non-tropical features should continue the extratropical transition process, and Dorian is expected to become extratropical in about 36 hours. Dissipation remains likely around day 4 as the system is absorbed by a larger non-tropical low.
Dorian is racing northeastward ahead of an upper-level trough. This trajectory and forward speed is likely to continue generally unabated for the next 5 days. On this track, Dorian should impact Nova Scotia tomorrow night, likely as a hurricane or at least a hurricane-force extratropical low. It should then continue into Newfoundland on Sunday morning as a weaker cyclone before entering the far North Atlantic a day later.
FORECAST MAX WINDS
INIT 06/2100Z 90 KT 105 MPH
12H 07/0600Z 85 KT 100 MPH
24H 07/1800Z 75 KT 85 MPH
36H 08/0600Z 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 08/1800Z 55 KT 65 MPH...POST-TROP/EXTRATROP
72H 09/1800Z 40 KT 45 MPH...POST-TROP/EXTRATROP
Atlantic/2015/02L/Archive/6

## Public advisory

TROPICAL STORM BILL ADVISORY NUMBER 6

WIKI-HURRICANES FORECAST CENTER

400 PM CDT TUE JUN 16 2015

...BILL PRODUCING HEAVY RAINFALL ACROSS SOUTHEASTERN TEXAS...

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

LOCATION... 28.4N 96.8W

ABOUT 25 MI...40 KM W OF PORT O'CONNOR TEXAS

MAXIMUM SUSTAINED WINDS...45 KT...50 MPH...85 KM/H

MINIMUM BAROMETRIC PRESSURE...999 MB...29.50 INCHES

PRESENT MOVEMENT...NNW OR 330 DEGREES... AT 8 KT...9 MPH...15 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 400 pm CDT, the center of Tropical Storm Bill was located at 28.4N, 96.8W, or about 25 miles (40 km) west of Port O'Connor, Texas. Maximum sustained winds were 45 knots (50 mph, 85 km/h), with higher gusts. The minimum barometric pressure was 999 millibars (hPa; 29.50 inHg), and the system was moving north-northwest at 8 knots (9 mph, 15 km/h). Bill is expected to gradually weaken over the South Plains over the coming days. However, the threat for gusty winds, torrential rainfall capable of producing life-threatening inland flooding, and storm surge along the coastline will continue.

NEXT ADVISORY

Next complete advisory at 1000 pm CDT.

$$

Forecaster YE

## Discussion

TROPICAL STORM BILL DISCUSSION NUMBER 6

WIKI-HURRICANES FORECAST CENTER

400 PM CDT TUE JUN 16 2015

Tropical Storm Bill made landfall at around 1640 UTC time today in on Matagorda
Island, Texas with winds of 55 knts. Since then, an inland decay rate would support cutting the intensity down to 45 knts from 55 knts. Gradual weakening is expected, though as mentioned in previous discussions, the rate is somewhat uncertain. In fact, the UKMET last night shows intensification.

The track forecast for Bill is simple for a change. The storm has taken on a slow northwesterly motion this morning as it rounds the southwestern periphery of a potent mid-level ridge across the Southeast United States that is bringing extreme heat to the Carolinas. This motion is expected for the next 36 to 48 hours. Thereafter, an approaching trough should recurve Bill toward the north and later to the northeast. All models are in good agreement, and the track forecast is an update from the previous one.

INIT 16/2100Z 28.4N 96.8W 45 KT 50 MPH

12H 17/0600Z 29.8N 97.5W 40 KT 45 MPH...INLAND

24H 17/1800Z 31.9N 97.8W 30 KT 35 MPH...INLAND

36H 18/0600Z 33.5N 97.2W 25 KT 30 MPH...INLAND/REMNT LOW

48H 18/1800Z 34.8N 95.8W 25 KT 30 MPH...INLAND/REMNT LOW

72H 19/1800Z 36.5N 92.1W 20 KT 25 MPH...INLAND/REMNT LOW

96H 20/1800Z 39.1N 85.9W 15 KT 20 MPH...INLAND/REMNT LOW

120H 21/1800Z...ABSORBED BY A FRONTAL SYSTEM

$$

Forecaster YE
Atlantic/2019/01Q/Archive/12

Tropical Storm Iba Discussion Number 12

Wiki-Hurricanes Forecast Center

12:00 PM AST Tue Mar 26 2019

Iba is not well organized this morning, with the entirety of its low-level cumulus circulation exposed and well-removed from any stout convective activity, largely limited to a single spiral band to the south. Cirrus streaming from Brazil and passing largely unabated over Iba's center of circulation are indicative of the rather hostile shearing environment caused by the nearby subtropical jet, and mid-level conditions are particularly dry. SAB has estimated a current intensity value of T3.0/45kt, lagged off of their previous estimates. Iba has built slightly more convection since dawn, but certainly not enough to induce any uptick in the winds. A 12:30z scatterometer pass from ASCAT-A showed no explicit gale-force points However, given the size of this 30 kt region, weakening is likely slowed somewhat so the intensity for Iba remains at 35 kt.

We're nearing the end of the road for Iba as it curves east and then southeastward into the drier and less favorable conditions of the South Atlantic subtropics -- conditions which are normally reflective of the South Atlantic as a whole. Iba will likely drop below tropical storm intensity later today and taper off as it transitions into a post-tropical remnant low by Thursday. Whatever is left -- probably not much at all -- may be absorbed by a developing trough feature late in the forecast.

FORECAST MAX WINDS

INIT 26/1500Z 35 KT 40 MPH

12H 27/0000Z 30 KT 35 MPH

24H 27/1200Z 30 KT 40 MPH

36H 28/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW

48H 28/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW

72H 29/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW

96H 30/1200Z 15 KT 25 MPH...POST-TROP/REMNT LOW

120H 31/1200Z...DISSIPATED
Atlantic/2015/02L/Archive/9

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 9

WIKI-HURRICANES FORECAST CENTER

10:00 AM CDT WED JUN 17 2015

SUMMARY OF 10:00 AM CDT...15:00 UTC...INFORMATION

LOCATION... 32.6N 97.6W

ABOUT 20 MI...30 KM SW OF FORT WORTH, TEXAS

MAXIMUM SUSTAINED WINDS...25 KT...30 MPH...50 KM/H

MINIMUM BAROMETRIC PRESSURE... 1003 MB...29.62 INCHES

PRESENT MOVEMENT...N AT 13 KT...15 MPH...24 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 10:00 am CDT, the center of Tropical Depression Bill was located at 32.6N, 97.6W, or about 20 miles (30 km) southwest of Fort Worth, Texas. Maximum sustained winds were 25 knots (30 mph, 50 km/h), with higher gusts. The minimum barometric pressure was 1003 millibars (hPa; 29.62 inHg), and the system was moving towards the north at 13 knots (15 mph, 28 km/h). Bill is expected to turn northeast and eventually north-northeast in advance of an approaching upper-level trough over the coming days while steadily losing tropical characteristics.

NEXT ADVISORY

Next complete advisory at 4:00 pm CDT.

$$

Forecaster TAWX14

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 9

WIKI-HURRICANES FORECAST CENTER

10:00 AM CDT WED JUN 17 2015

Bill remains a well-organized tropical cyclone over land this morning. A combination of radar and satellite shows an expanse of heavy shower and thunderstorm activity north and east of the center, with a prominent spiral band extending southward toward the southeast Texas coastline. Surface observations reveal that the cyclone continues to maintain a defined low-level center, with minimum barometric pressures across the Dallas-Fort Worth metroplex in the 1002-1003 mb range. Sustained winds appear to have decreased slightly, although gusts to just under gale-force have been recorded. Steady weakening is expected over the coming days as Bill pushes further inland, and it is expected to transition into a post-tropical cyclone within 36 hours. The remnant low of the system should become absorbed by an approaching frontal system as the vortex moves north-northeast and eventually east-northeast.

INIT 17/1500Z 32.6N 97.2W 25 KT 30 MPH

12H 18/0000Z 34.1N 97.1W 25 KT 30 MPH

24H 18/1200Z 35.4N 96.5W 25 KT 30 MPH

36H 19/0000Z 35.7N 94.9W 20 KT 25 MPH...INLAND/REMNT LOW

48H 19/1200Z 36.6N 92.8W 20 KT 25 MPH...INLAND/REMNT LOW

72H 20/1200Z 38.5N 88.4W 15 KT 25 MPH...INLAND/REMNT LOW

96H 21/1200Z...DISSIPATED

$$

Forecaster TAWX14
Atlantic/2019/08L/Archive/3

The system has continued to organize since the previous advisory as convection intensifies and becomes more symmetric. The low-level circulation remains situated on the southern edge of this thunderstorm activity as the storm is still in its formative stages. Still, satellite intensity estimates are increasing, including a T2.5/35kt estimate from TAFB and a 42kt estimate from SATCON. Given the increase in organization this evening, I have raised the initial intensity to 35kt and upgraded the depression to Tropical Storm Gabrielle.
The intensity forecast has become quite complicated. Mid-level relative humidity and wind shear values are conducive in the short term, but ocean temperatures are only marginal. The culmination of these factors should allow for some slight organization 36 hours or so. Beyond that time, Gabrielle should interact with the TUTT across the North Atlantic, increasing wind shear atop the cyclone. However, there are two things to consider regarding this interaction. One, Gabrielle is expected to maintain its anticyclone despite close proximity to the TUTT cell, and in fact the TUTT may aid in an equatorward outflow channel as it breaks off into a cut-off low and Gabrielle rotates around the north side of the feature in about 4 to 5 days. Second, even as the TUTT temporarily disrupts Gabrielle's upper-level high pressure system, the shear is expected to be divergent in nature which may aid in only minor disruption to the system. Model guidance has continued to trend upward, with the SHIPS, LGEM, and ECMWF maintaining a moderate tropical storm over the next 5 days. The HWRF goes much further, especially on days 4 and 5, by showing a major hurricane. This is obviously an outlier, at least at the current time. Trends this evening do give more confidence in Gabrielle surviving the next few days, with the potential for strengthening at the end of the period, and this has been reflected in the updated forecast.
High pressure over Africa, high pressure over the Azores, and a mid-level low over the central Atlantic should work in conjunction to keep Gabrielle on a northwest heading for the entirety of the five day forecast window. Models are in unanimous agreement regarding this solution, and I see no reason to deviate from that expectation.
FORECAST MAX WINDS
INIT 04/0300Z 35 KT 40 MPH
12H 04/1200Z 40 KT 45 MPH
24H 05/0000Z 45 KT 50 MPH
36H 05/1200Z 50 KT 60 MPH
48H 06/0000Z 50 KT 60 MPH
72H 07/0000Z 45 KT 50 MPH
96H 08/0000Z 45 KT 50 MPH
Atlantic/2019/05L/Archive/38

Dorian's satellite appearance continues to deteriorate slowly. Since the last advisory, the most significant change is the quality of the eye, which is increasingly ragged and cooling as it fills with clouds. Aircraft reconnaissance recently entered the hurricane and found flight level winds near 115 kt, which supports an initial intensity of 105 kt.
Upwelling is the main concern regarding Dorian's intensity for the time being, so long as it remains in nearly the same location. This will continue to weaken the storm steadily as it remains in place. The coupled hurricane models show that upwelling will remain a significant factor throughout the day today before Dorian begins to move over unfamiliar waters tomorrow, which will be warmer and more supportive. Wind shear is also forecast to increase to moderate levels today, which should aid weakening. Mid-level relative humidity will also continue to fall as upwelling reduces stability and moisture availability, notwithstanding further injection of dry air as Dorian collects it off the continental US. Tomorrow, with warmer sea surface temperatures Dorian's weakening should slow a little, but then it will have increasing shear to deal with, especially beyond day 2 as it interacts with a trough. By the end of day 5, Dorian will have transitioned into an extratropical cyclone off the northeastern US.
This time yesterday, Dorian was approaching Grand Bahama Island and currently it still sits barely to the north of the island. It has hardly moved in the last twelve hours or so, but it should begin to track toward the north-northwest later today into a weakness between a mid-level ridge centered near Bermuda and another one over the central US. The approach of an upper-level trough will then cause a turn toward the northeast as it gets picked up in the mid-latitude westerlies. Over the following days it will continue to accelerate to the northeast. Regardless of exact track, Dorian is still expected to affect the southeastern United States, especially as it becomes larger and gradually loses tropical characteristics, such as when it approaches the Carolinas.
FORECAST MAX WINDS
INIT 02/0300Z 105 KT 120 MPH
12H 03/1200Z 95 KT 110 MPH
24H 03/0000Z 90 KT 105 MPH
36H 04/1200Z 85 KT 100 MPH
48H 04/0000Z 80 KT 90 MPH
72H 05/0000Z 70 KT 80 MPH
96H 06/0000Z 65 KT 75 MPH
Atlantic/2019/07L/Archive/5

Fernand is a poorly-organized tropical cyclone this morning. A majority of its convective activity moved inland into northern Mexico several hours ago, leaving behind an increasingly elongated and exposed low-level circulation that is approaching the coastline. Moderate to strong easterly wind shear continues to affect the storm, and this should keep Fernand disorganized as it makes landfall a few hours from now. The system is expected to quickly dissipate once inland.
High pressure over the Southwest United States is steering Fernand toward the west-northwest, and that motion should continue unabated for the little time Fernand has left as a coherent system.
FORECAST MAX WINDS
INIT 04/1500Z 40 KT 45 MPH
12H 05/0000Z 25 KT 30 MPH...INLAND
Atlantic/2015/02L/Archive/17

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 17

WIKI-HURRICANES FORECAST CENTER

10:00 AM CDT FRI JUN 19 2015

...BILL A TROPICAL DEPRESSION...STILL...

SUMMARY OF 10:00 AM CDT...15:00 UTC...INFORMATION

LOCATION... 36.3N, 91.4W

ABOUT 1115 MI...185 KM NE OF LITTLE ROCK, ARKANSAS

MAXIMUM SUSTAINED WINDS...20 KT...25 MPH...35 KM/H

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

PRESENT MOVEMENT...ENE AT 18 KT...20 MPH...32 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 10:00 am CDT, the center of Tropical Depression Bill was located at 36.3N, 94.1W, or about 115 miles (185 kilometers) northeast of Little Rock, Arkansas. Maximum sustained winds were 20 knots (25 mph, 35 km/h), with higher gusts. The minimum barometric pressure was 1006 millibars (hPa; 29.71 inHg), and the system was moving east-northeast at 18 knots (20 mph, 32 km/h). Bill is expected to lose its tropical characteristics over the next day as it continues east-northeast.

NEXT ADVISORY

Next complete advisory at 400 pm CDT.

$$

Forecaster TAWX14

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 17

WIKI-HURRICANES FORECAST CENTER

10:00 AM CDT FRI JUN 19 2015

There isn't much to report on Tropical Depression Bill. The system continues to maintain a well-defined and closed circulation, and convection has actually increased near the center compared to 24 hours ago. However, FSU phase diagrams indicate the circulation is only marginally warm core, and surface analyses indicate a frontal boundary intruding on the outskirts of the circulation. Bill is expected to become post tropical within 24 hours as it continues east-northeast.

INIT 19/1500Z 36.3N 94.1W 15 KT 20 MPH...TROPICAL DEPRESSION

12H 20/0000Z 36.9N 89.8W 15 KT 20 MPH...TROPICAL DEPRESSION

24H 20/1200Z 37.8N 87.0W 15 KT 20 MPH...POST-TROPICAL/REMNT LOW

36H 21/0000Z 39.0N 82.3W 15 KT 20 MPH...POST-TROPICAL/REMNT LOW

48H 21/1200Z...MERGED WITH EXTRATROPICAL CYCLONE

$$

Forecaster TAWX14
Atlantic/2019/02L/Archive/2

Tropical Depression Two looks a bit dishevelled this morning. ASCAT passes from near the beginning of this cycle showed winds of 25-30 kt concentrated near regions of thunderstorm activity. The circulation continues to be broad and the deepest convection has moved off to the southwest, though some convection is still firing near the assumed center. A recon flight recently departed for this storm which will provide valuable data for the next advisory. Dvorak intensity estimates continue to come in from SAB at T1.5/25kt as of 06z. The intensity of the depression remains held at 30 kts.
Forecast confidence remains low as the depression is forecast to be under the influence of several different features inducing various steering patterns. In general, the system is expected to track westerly under the influence of the mid-level ridge currently located near the NM/CO border. As the ridge decays, the storm will make a turn to the north.
Northerly shear is the main factor currently affecting Two which will hinder its development. This shear will remain in place for the next 12 to 24 hours before the storm begins to generate an anticyclone aloft in combination with the motion of an upper-level ridge which will dip southwest over the system. This will result in a decrease in wind shear which will allow for significant strengthening. SSTs near 30C and above are in the track of the storm and mid-level moisture is expected to be more than adequate as well. Wind shear is only likely to make an appearance once again as the storm is already moving inland late on day 2 or 3, so brisk strengthening is forecast up until landfall. The forecast points at 72h and beyond have been adjusted downward in intensity as the guidance, even those with eastern solutions such as ECMWF, show Two inland by this point.
FORECAST MAX WINDS
INIT 11/0900Z 30 KT 35 MPH
12H 11/1800Z 35 KT 40 MPH
24H 12/0600Z 45 KT 50 MPH
36H 12/1800Z 55 KT 65 MPH
48H 13/0600Z 75 KT 85 MPH
72H 14/0600Z 55 KT 65 MPH...INLAND
96H 15/0600Z 30 KT 35 MPH...INLAND
Atlantic/2019/02L/Archive/18

Barry has been producing unorganized convection within the vicinity of its low-level circulation center over Arkansas, enough to retain the classification of tropical cyclone. Surface observations continue to indicate that the minimum central pressure is maintained at 1009mb and perhaps it was a little lower in the past advisory, given a 07z 1008.5mb reading. The highest currently measured sustained wind is 20kt, but given the sampling and that the pressure has held constant, the intensity of Barry remains 25kt.
The forecast remains much the same for the depression. It will continue to track generally northward before turning to the northeast around a ridge over the southeast US. During this time it will continue to weak over land, degenerating into a remnant low later today before opening into a trough around 48h.
FORECAST MAX WINDS
INIT 15/0900Z 25 KT 30 MPH...INLAND
12H 15/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 16/0600Z 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 16/1800Z 15 KT 20 MPH...POST-TROP/REMNT LOW
Atlantic/2019/10L/Archive/11

Jerry has deteriorated some more since the previous advisory under persistent 20-30kts of wind shear, and is now structured in quite a disheveled manner typical of struggling storms over the central Atlantic, lacking a defined core of any sort and being buoyed by occasional flareups of convection over the center of circulation. There has been some recovery since that time, but likely not enough to sustain Jerry's earlier intensity. A series of center passes by an NOAA reconnaissance aircraft between 17-18z found peak flight level winds of 67kt and peak SFMR values of 61kt while repeatedly investigating an area within 20nmi of the center of circulation. Based on these values and the ill-defined convective structure of Jerry, the initial intensity has been reduced to 60kt, making it a tropical storm.
The combined effects of an arid air column and strong wind shear from channelized northwesterly upper-level flow have been impinging on Jerry since its hurricane honeymoon, and the effects of wind shear are expected to enhance dry air entrainment with shear remaining in place over the next three days. Afterwards, Jerry is expected to enter a more divergent flow regime, a la Humberto a week ago, and intensify towards the end of the forecast window. This should result in intensification. Poleward mosture advection via the trough enhanced by outgoing Humberto should give Jerry access to sufficient water vapor with which to develop persistent convection in lieu of weakening.
Jerry is forecast to navigate towards a weakness in subtropical ridging over the next few days, curving towards the north and northeast in 2-3 days. This trajectory implies possible impacts in Bermuda in 4-5 days. There are some finer mechanics in the forecast track, particularly possible interactions between Jerry, a potential developing tropical cyclone near the Windward Islands, and a strengthening ridge over the southeastern United States that will need to be ironed out further down the road.
FORECAST MAX WINDS
INIT 20/2100Z 60 KT 65 MPH
12H 20/0600Z 55 KT 65 MPH
24H 21/1800Z 50 KT 60 MPH
36H 21/0600Z 45 KT 50 MPH
48H 22/1800Z 45 KT 50 MPH
72H 23/1800Z 50 KT 60 MPH
96H 24/1800Z 60 KT 75 MPH
Atlantic/2019/09L/Archive/21

Humberto is in the midst of an extratropical transition this morning. Since the last advisory, the centre has become exposed and the convection is now pushed off to the north. This tends to indicate that some weakening has occurred, so initial intensity has been set at 100 kt for this advisory. Global models are all pretty unanimous that extratropical transition will be complete within 24 hours, so the intensity foreccast remains similar to the previous one with dissipation forecast at about 5 days.
The hurricane is currently moving quickly towards the northeast. A turn more towards the north-northeast due to interaction with a cut-off low is expected today as the system completes its extratropical transition. Soon thereafter, the storm will turn back towards the northeast out into the open Atlantic.

FORECAST MAX WINDS
INIT 19/1500Z 100 KT 115 MPH
12H 20/0000Z 85 KT 100 MPH
24H 20/1200Z 70 KT 80 MPH...POST-TROP/EXTRATROP
36H 21/0000Z 65 KT 75 MPH...POST-TROP/EXTRATROP
48H 21/1200Z 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 22/1200Z 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 23/1200Z 50 KT 60 MPH...POST-TROP/EXTRATROP
Atlantic/2019/09L/Archive/5

An Air Force reconnaissance aircraft investigating Tropical Storm Humberto found peak flight-level winds of 64kt and maximum SFMR winds around 45kt. A blend of these values supports upping the initial intensity to 50kt. Humberto has become better stacked today and is in the beginning stages of forming an inner core. In an environment of low wind shear, adequate mid-level relative humidity, and high ocean temperatures, steady to quick intensification is expected over the coming days, and Humberto is expected to become a major hurricane in 3 to 4 days from now. Increased shear should induce weakening on day 5.
Recon fixes show that Humberto continues to move north-northwest. However, a turn toward the north is expected tonight, followed by an acceleration to the north-northeast by Monday and beyond as mid-latitude westerlies interact with the hurricane. This track should bring Humberto very close to Bermuda in about 4 days. An alternate scenario as indicated by a non-significant number of ECMWF ensemble members is that high pressure builds in the wake of the mid-level trough, forcing the cyclone back toward the west. This is an unlikely solution but one that requires close monitoring.
FORECAST MAX WINDS
INIT 15/0300Z 50 KT 60 MPH
12H 15/1200Z 60 KT 70 MPH
24H 16/0000Z 70 KT 80 MPH
36H 16/1200Z 80 KT 90 MPH
48H 17/0000Z 90 KT 105 MPH
72H 18/0000Z 100 KT 115 MPH
96H 19/0000Z 95 KT 110 MPH
Atlantic/2018/03L/Archive/9

Tropical Storm Chris Discussion Number 9

Wiki-Hurricanes Forecast Center

5:00 AM EDT Tue Jul 10 2018

Chris' cloud pattern has become better organized since the previous advisory, with the formation of a prominent spiral band in the southern quadrant, as well as deeper convection to the northwest of the center where it has until recently been lacking in vigor. The combination of dry air and cold water upwelling continues to hinder the formation of a solid eyewall, though it would not take much for this process to complete. A reconnaissance aircraft is currently investigating the cyclone, reporting a minimum barometric pressure of 993mb. Flight-level winds of 67kt support surface winds of around 55kt; however, the initial intensity has been held at 60kt under the assumption stronger winds exist in either the northeast or southwest quadrants. In stationary systems, there is no preferred quadrant of maximum winds.

The storm has been meandering for days, but things are about to change. An upper-level trough is forming over Canada, and this feature should push southward later today, providing sufficient steering flow to direct Chris to the northeast. This track should keep it well offshore the East Coast of the United States, but bring it very close to Newfoundland in about three days as an extratropical cyclone.

Water temperatures at Buoy 41002 southwest of the center have continued to fall to near 25C, indicating that cold water upwelling continues. However, Chris has a fairly compact radius of maximum winds, and it is beginning to meander away from the location it has been for the past several days. This should allow for steady intensification as the system remains in a low wind shear environment. In fact, as the upper-level trough moves southward, outflow channels should only become more distinct. Dry air continues to lurk near the cyclone, but the combination of light upper-level winds and warm ocean waters should keep this issue at bay. The intensity forecast is largely a reflection of the previous one, calling for Chris to become a hurricane in a few hours and peak with winds of 80kt before undergoing extratropical transition.

FORECAST POSITIONS AND MAX WINDS

INIT 10/0900Z 60 KT 70 MPH

12H 10/1800Z 70 KT 80 MPH

24H 11/0600Z 80 KT 90 MPH

36H 11/1800Z 80 KT 90 MPH

48H 12/0600Z 75 KT 85 MPH

72H 13/0600Z 60 KT 70 MPH...POST-TROP/EXTRATROP

96H 14/0600Z 40 KT 45 MPH...POST-TROP/EXTRATROP

120H 15/0600Z...DISSIPATED