recursal/Fanatic-Fandom huggingface dataset:
Atlantic/2019/07L/Archive/1

A new tropical depression has formed in the Gulf of Mexico. High-resolution visible imagery this morning indicates that the low-level circulation of the broad disturbance we had been tracking has become sufficiently defined to meet the criteria of a tropical cyclone. Deep convection is on the increase near the center of the storm, with formative banding to the west and the northeast. ASCAT data from last night showed peak winds of 30kt, and that is the initial intensity used for this advisory.
The depression is experiencing moderate northeasterly wind shear, and light to moderate shear should continue through the forecast period. This, combined with the broad nature of the depression's circulation, should prevent rapid intensification despite ocean temperatures above 30C and mid-level relative humidity values around 65 percent. That being said, TD Seven is expected to attain tropical storm strength later today, with room for a little more growth thereafter. Quick dissipation should occur after landfall in northern Mexico in about 48 hours.
Seven is currently drifting toward the southwest, but a turn toward the west-northwest should occur as it organizes and is steered by a mid-level ridge over the Southwestern United States. This should bring the tropical depression to the coastline of northern Mexico in about 48 hours. The chances that the system deviates northward into South Texas appear low. Models are in good agreement regarding the system's track.
FORECAST MAX WINDS
INIT 03/1500Z 30 KT 35 MPH
12H 04/0000Z 35 KT 40 MPH
24H 04/1200Z 35 KT 40 MPH
36H 05/0000Z 40 KT 45 MPH
48H 05/1200Z 25 KT 30 MPH...INLAND
Atlantic/2019/12L/Archive/14

Karen has once again degenerated into a remnant low. Very little deep convection remains associated with the system, and first visible imagery of the storm shows that it looks much more like a trough of low pressure than a tropical cyclone. This is the final advisory. Karen is currently moving east-northeast as part of its cyclonic loop. It is expected to loop back to the west as it begins to dissipate.

FORECAST MAX WINDS
INIT 27/1500Z 25 KT 30 MPH...POST-TROP/REMNT LOW
12H 28/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW
24H 28/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW
36H 29/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW
48H 29/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2019/06L/Archive/3

Six's satellite presentation has improved over the past few hours with the general improvement of the convective pattern. The depression's low-level circulation remains broad and ill defined, however. Dvorak intensity estimates remain the same, so with minimal changes the intensity remains 30 kt.
The depression is still facing moderate wind shear around 15 kt. This shear is expected to remain fairly constant or decrease slightly, allowing for some slow intensification over the next two days before an approaching extratropical low introduces hostile conditions of higher wind shear. Sea surface temperatures remain near 28-29C for the time being, decreasing significantly beyond 48h as well. Some baroclinic forcing may result in further intensification on day 3, but the cyclone will be transitioning to post-tropical and should complete its transition sometime on day 4, dissipating shortly thereafter.
The depression is meandering slowly this morning in an absence of steering currents. The system should move slowly generally northward over the day or two
The depression has moved eastward today, albeit very slowly. Given collapsed steering currents, rather random wobbling is expected for the next day or so as it gradually gets picked up by an upper-level trough. On day 3, the system should then begin to accelerate northeast as the influence of the trough becomes greater, passing near or over Nova Scotia as it becomes extratropical.
FORECAST MAX WINDS
INIT 27/0900Z 30 KT 35 MPH
12H 27/1800Z 35 KT 40 MPH
24H 28/0600Z 35 KT 40 MPH
36H 28/1800Z 40 KT 45 MPH
48H 29/0600Z 40 KT 45 MPH
72H 30/0600Z 45 KT 50 MPH
96H 31/0600Z 45 KT 50 MPH...POST-TROP/EXTRATROP
Atlantic/2019/09L/Archive/10

Humberto is continuing to quickly strengthen this morning. A hurricane reconnaissance aircraft has been investigating the storm this morning and has found a strengthening hurricane. A well defined eye has appeared in satellite imagery, surrounded by a dense CDO. Satellite appearance has improved considerably, with SAB/TAFB at T5.0/90 kt. Pressure has fallen and the winds have upped considerably in the flight level, though it appears they are struggling to mix to the surface. Dropsonde data confirms this, so the initial intensity is a conservative blend of the 90 kt flight-level winds and the 72 kt SFMR winds found. Initial intensity is set at 75 kt for this advisory.
There is no reason that Humberto should cease continued intensification throughout the next day or two. In fact, SHIPS indicates that continued rapid intensification is possible during this time frame while the hurricane moves over the warm gulf stream waters. It seems likely to me, given the state of the inner core at this time, that the system should attain major hurricane strength over the course of the next day. After this time, baroclinic forcing should allow the storm to maintain intensity well as shear increases up until extratropical transition commences. By day 5 the system is expected to have completed this transition into a power extratropical low.
Recon fixes have the system moving slowly east-northeast. This movement is expected to continue for the next 12 hours, with the storm moving slowly around the northwestern portion of a subtropical ridge. A southward dip in a trough to the system's north will accelerate the storm northeastward in 36 hours. It seems increasingly likely that the storm will miss Bermuda, leaving only minimal tropical storm impacts to the island. By day 4, it is increasingly unclear how the cyclone will interact with the trough. However, regardless of this uncertainty any impacts to land are unlikely.

FORECAST MAX WINDS
INIT 16/1500Z 75 KT 85 MPH
12H 17/0000Z 85 KT 100 MPH
24H 17/1200Z 100 KT 115 MPH
36H 18/0000Z 105 KT 120 MPH
48H 18/1200Z 105 KT 120 MPH
72H 19/1200Z 95 KT 110 MPH
96H 20/1200Z 75 KT 85 MPH
Atlantic/2019/10L/Archive/14

Jerry is a disheveled tropical cyclone this afternoon. It is producing very deep convection in an amorphous blob largely displaced southeast of the low-level circulation. An Air Force reconnaissance aircraft investigating the system this morning found the pressure had risen to 1002mb. More recent ASCAT data supports maintaining the initial intensity at 50kt.
Strong upper-level winds and dry air are negatively affecting Jerry this afternoon, and this hostile environment should persist for another 36 hours or so. Beyond that time, while ocean temperatures will remain warm, wind shear should decrease to more favorable levels and open the door for intensification. Jerry is expected to be in close proximity to a large upper-level trough to the northwest, a similar 200mb setup to what we witnessed with Hurricane Humberto. If the cyclone is too close to this trough, it will result in weakening. Alternatively, Jerry's position on the southeast side of this trough could provide a very favorable 200mb setup for intensification if the nature of the interaction is just right. Determining these interactions is difficult several days out. Therefore, the updated intensity forecast is largely similar to the previous one and tends to lean toward a more favorable interaction for now.
Jerry has turned northwest as it reaches the western periphery of a mid-level ridge to its northeast and simultaneously begins to interact with an upper-level trough across the western Atlantic. This interaction should result in the cyclone moving north over the next 72 hours, followed by a north-northeast track thereafter. Jerry is expected to pass very near the island of Bermuda about 3 days from now.
FORECAST MAX WINDS
INIT 21/2100Z 50 KT 60 MPH
12H 22/0600Z 45 KT 50 MPH
24H 22/1800Z 45 KT 50 MPH
36H 23/0600Z 55 KT 65 MPH
48H 23/1800Z 60 KT 70 MPH
72H 24/1800Z 65 KT 75 MPH
96H 25/1800Z 80 KT 95 MPH
Atlantic/2019/05L/Archive/15

Dorian has continued to strengthen this morning. Radar out of San Juan continues to show the system's formative eyewall structure, and it depicts heavy reflectivity values rotating upshear, an indication that further organization continues. An Air Force reconnaissance plane investigating Dorian has found peak flight-level winds of 72kt, with peak believable SFMR values near 59kt. Both of these values support upping the initial intensity to 60kt. The minimum central pressure is estimated at 1000mb based on a 1002mb dropsonde in 18kt surface winds.
Dorian has had a tendency to move far more poleward than any of us expected, and the initial motion is north of northwest this morning. On its current trajectory, Dorian is expected to pass very close to Puerto Rico this evening, although it would not be surprising if the cyclone ultimately missed the island to the east. Dorian is expected to continue moving northwest until Friday morning, when high pressure is expected to build off the Southeast United States. This ridge should force the system west-northwest and perhaps west toward the eastern coast of Florida. The biggest question left in terms of track is whether Dorian actually makes it to the state, with some model guidance indicating that the area of high pressure may break down just in time to allow Dorian to curve more toward the northwest and north, threatening other states up the coast. In past cases, the tendency has been for modelling to break down these ridges too quickly and to underestimate their strength. So, for now, I continue to expect Dorian to be very near the coastline of Florida about 5 days from now.
The upper-level environment around Dorian is conducive to strengthening, and it should generally remain that way for the next several days except for a slight uptick in shear values tonight and early tomorrow. Given that the system is on track to avoid or only barely brush Puerto Rico, land interaction is not expected to be a significant factor. Ocean temperatures between 29-30C and 700-500mb relative humidity values that should gradually climb to over 70 percent both favor significant strengthening, a solution depicted by all reliable models now. It is increasingly likely Dorian will approach major hurricane strength by the end of the day 5 period, if not sooner. Some models such as the reliable HWRF suggest Category 4 intensity may be attainable. For now, I have further upped our intensity forecast to show a 100kt cyclone on day 5. Further adjustments may still be necessary.
FORECAST MAX WINDS
INIT 28/1500Z 60 KT 70 MPH
12H 29/0000Z 60 KT 70 MPH
24H 29/1200Z 65 KT 75 MPH
36H 30/0000Z 70 KT 80 MPH
48H 30/1200Z 75 KT 85 MPH
72H 31/1200Z 90 KT 105 MPH
96H 01/1200Z 95 KT 110 MPH
Atlantic/2019/03L/Archive/5

Tropical Depression Three has dissipated. An Air Force reconnaissance aircraft investigated the system this morning, finding a closed circulation on their first pass. However, upon intercepting the center for a second time and continuing into the northwest quadrant, the plane found winds out of the southwest or south. This indicates that Three degenerated to an open trough around the time of the 15z advisory. Recent visible satellite imagery continues to highlight convective activity concentrated around a vigorous mid-level circulation; however, low-level cloud motions do not suggest a new well-defined center has formed. An approaching cold front should continue to promote unfavorable surface flow across the western Atlantic, and it will also act to dramatically increase upper-level winds in the short term. Thus, this is the final advisory on Three and regeneration is not expected. The remnants of the system are now moving north-northeast and should continue in that general direction until they merge with the front in the vicinity of eastern North Carolina.
FORECAST MAX WINDS
INIT 23/2100Z 30 KT 35 MPH
Atlantic/2018/05L/Archive/8

Tropical Storm Ernesto Discussion Number 8

Wiki-Hurricanes Forecast Center

5:00 PM AST Fri Aug 17 2018

Ernesto is on its last leg as a tropical cyclone. Infrared imagery shows that the storm continues to produce deep convection near the center, the byproduct of upper-air temperatures near -58C despite ocean temperatures only around 21C, but that this convection is beginning to be wisked away toward the northeast. This is a sign that Ernesto is beginning extratropical transition as it interacts with a trough approaching from the west. This transition should be complete in a few hours, and the remnants of Ernesto are likely to remain distinct until in the vicinity of the United Kingdom in 2 days where they should ultimately dissipate.

INIT 17/2100Z 40 KT 45 MPH

12H 18/0600Z 40 KT 45 MPH...POST-TROP/EXTRATROP

24H 18/1800Z 35 KT 40 MPH...POST-TROP/EXTRATROP

36H 19/0600Z 30 KT 35 MPH...POST-TROP/EXTRATROP

48H 19/1800Z...DISSIPATED
Atlantic/2018/04L/Archive/1

Subtropical Storm Debby Discussion Number 1

Wiki-Hurricanes Forecast Center

11:00 AM AST Tue Aug 7 2018

The area of low pressure in the far North Atlantic has gained sufficient characteristics to be declared Subtropical Storm Debby. The system has a classic subtropical appearance, with deepest convection relegated to bands away from a cloud-free center. Upper-level outflow has been expanding west and north. A recent ASCAT pass confirmed tropical storm-force winds removed from the low-level circulation, and thus the intensity is set to 35kt. Over water temperatures that should cool to near 24C in a day or less, and in an environment where shear should increase to 15kt during that same time, tropical transition is not expected, and neither is any strengthening. A upper-level trough approaching from the west should cause Debby to dissipate within 48 hours as it becomes embedded within the feature. The storm is moving north at the present time but should accelerate northeast beginning tomorrow for the time it remains a separate entity.

FORECAST POSITIONS AND MAX WINDS

INIT 07/1500Z 35 KT 40 MPH

12H 08/0000Z 35 KT 40 MPH

24H 08/1200Z 35 KT 40 MPH

36H 09/0000Z 30 KT 35 MPH

48H 09/1200Z...DISSIPATED
Atlantic/2019/09L/Archive/20

Humberto is beginning his final transition into a powerful extratropical cyclone this evening, which has unusually helped intensify the system into an impressive category 4 hurricane. Since the last advisory, the storm has broken apart into a few powerful baroclynic jets surrounding a much warmer central dense overcast with no eye feature. In fact, Humberto looks like quite a mess at the moment. Yet, an aircraft reconnaissance plane currently in the system and surface observations in Bermuda has confirmed that the system has in fact strengthened into a category 4 hurricane. The plane has found flight level winds of 120 kt and a maximum SFMR reading of 115 kt far from the centre to the northeast of Bermuda. On the northern tip of Bermuda a maximum wind gust of 115 kt was detected, nearly 100 nmi from the centre. It is pretty clear these winds are not fully tropical in nature, almost certainly being amplified by baroclynic processes. The system remains tropical though, so initial intensity has unexpectedly been increased to 115 kt.
Now that extratropical transition has begun, global models all tend to agree that Humberto has about 36 hours until the transition is complete. The system is maintaining intensity well for now but it will eventually weaken as it begins to head out over the cool waters of the open Atlantic.
Humberto is still tracking quickly to the northeast as it begins turning more towards the north-northeast. This turn is as result of a nearby cut-off low that the hurricane will be interacting with. By day 2 as an extratropical cyclone, the system will once again turn very quickly to the east-northeast.

FORECAST MAX WINDS
INIT 19/0300Z 115 KT 130 MPH
12H 19/1200Z 105 KT 120 MPH
24H 20/0000Z 85 KT 100 MPH
36H 20/1200Z 70 KT 80 MPH...POST-TROP/EXTRATROP
48H 21/0000Z 65 KT 75 MPH...POST-TROP/EXTRATROP
72H 22/0000Z 60 KT 70 MPH...POST-TROP/EXTRATROP
96H 23/0000Z 50 KT 60 MPH...POST-TROP/EXTRATROP
Atlantic/2019/02L/Archive/16

Tropical Storm Barry is continuing its slow slog towards the Ozarks this afternoon. While the circulation is easily evident in surface observations, there are signs that the wind field is becoming increasingly ill-defined. As was the case for nearly the entirety of Barry's history, convection remains displaced far from the center. The KLCH radar site has been consistently showing an area of Doppler velocities greater than 40 kt at 2kft aloft. A tidal station at Calacasieu Pass has substantiated these measurements, reporting winds at about the gale-force threshold all morning and early afternoon. Sustained winds of 33 kt were reported in New Iberia at around 18z, which are some of the highest winds we've seen well inland. Based on these values, we'll keep Barry a minimal tropical storm for this advisory.
Steering is still weak, though the overall motion of Barry has been predominantly towards the north-northwest. The wind and pressure centers of Barry are in the process of decoupling, but overall the general circulation should move towards the north and later northeast with time around a low-level ridge over Florida. No change to the intensity forecast this advisory as inland decay is progressing as anticipated. The offshore patch of stronger winds should soon abate as Barry drifts farther inland.
FORECAST MAX WINDS
INIT 14/2100Z 35 KT 40 MPH...INLAND
12H 15/0600Z 30 KT 35 MPH...INLAND
24H 15/1800Z 25 KT 30 MPH...INLAND
36H 16/0600Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2015/02L/Archive/20

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 20

WIKI-HURRICANES FORECAST CENTER

0400AM CDT SAT JUN 20 2015

... BILL SURVIVING OVER EXTREME SOUTHERN INDIANA ...

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

LOCATION... 38.0N, 87.1W

ABOUT 75MI... 122KM WSW OF LOUISVILLE, KENTUCKY

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

MINIMUM BAROMETRIC PRESSURE... 1002 MB...29.59 INCHES

PRESENT MOVEMENT...ENE AT 16 KT...18MPH...30 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 0400 am CDT, the center of Tropical Depression Bill was located at 38.0N, 87.1W, or about 75 miles (122 kilometers) west-southwest of Louisville, Kentucky. Maximum sustained winds were 20 knots (25 mph, 35 km/h), with higher gusts. The minimum barometric pressure was 1002 millibars (hPa; 29.59 inHg), and the system was moving east-northeast at 16 knots (18 mph, 30 km/h). Bill is still expected to become a remnant low within the next 48 hours.

NEXT ADVISORY

Next complete advisory at 1000 am CDT.

$$
Forecaster Kalassak

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 20

WIKI-HURRICANES FORECAST CENTER

0400AM CDT SAT JUN 20 2015

Bill continues to survive well inland; its center lies within the state borders of Indiana at the moment. Infrared satellite imagery and radar indicate sustained convection over the center. Recent surface observations are indicating 20 knot winds just south of its well-defined center and one reading supports a lower pressure than previously observed, a surprising improvement from yesterday where the storm appeared to be on its last leg. Not only does Bill remain a tropical depression, but its intensity has been set to 20 kts. Though the recent developments may delay the transition to a remnant low pressure area, Bill is still expected to become one as it approaches an extratropical system which should affect its current development.

INIT 20/0300Z 38.0N 87.1W 20KT 25MPH

12HR 20/1200Z 38.7N 83.1W 15KT 20MPH

24HR 21/0000Z 39.5N 78.8W 15KT 20MPH ... REMNANT LOW

36HR 21/1200Z ... MERGED WITH EXTRATROPICAL CYCLONE

$$

Forecaster Kalassak
Atlantic/2019/07L/Archive/7

Fernand has dissipated. A combination of visible and shortwave satellite imagery indicates that the low-level circulation has dissolved over the mountainous terrain of northern Mexico. This is confirmed by a weather station south of the system reporting easterly winds where they should be westerly. Thus, this is the final advisory on Fernand. Heavy rainfall continues to affect northern sections of Mexico ahead of the surface trough, and this precipitation should continue as the remnants of the cyclone continue westward.
FORECAST MAX WINDS
Atlantic/2019/05L/Archive/16

Dorian has been rapidly intensifying over the past 12 hours and is now a hurricane. Satellite imagery shows a well-organized cyclone structurally, with several spiral bands, expanding upper-level outflow, a compact central dense overcast, and an eye that is intermittently evident on visible bands. The hurricane has been raking the U.S. Virgin Islands over the past several hours, with several observations above 95 mph in gusts. An Air Force reconnaissance plane from three hours ago found that the pressure had fallen to 999mb (1000mb dropsonde with 9kt surface winds) and surface winds were around 65kt. Since that time, the hurricane has improved in structure, and so the initial intensity is set to 70kt.
A slight uptick in upper-level winds is expected over the coming hours as Dorian interacts with a cut-off low. This shear may theoretically help inject some dry mid-level air into the core. On the other hand, there is little evidence of struggle at the present time, and it is completely possible that such a trend continues overnight, especially since land interaction is expected to be minimal now. Tomorrow and beyond, Dorian will find itself in an increasingly moist airmass, over water temperatures ranging from 28-30C, and embedded within a very low wind shear environment. The combination of these factors should favor significant strengthening, and once again I am forced to dramatically up the intensity forecast. Dorian may be near Category 4 strength as it approaches the eastern coast of Florida in five days.
The system is moving steadily northwestward this afternoon. A northwest trajectory should continue through Thursday night, with a gradual curve toward the west-northwest and then west as high pressure builds off the Southeast United States. While previous model runs opened the door for this high to weaken, perhaps allowing Dorian to curve northward near the coastline of Florida, the trend today (as expected) has been for this ridge to be stronger and last longer than originally anticipated. Thus, the chances of a major hurricane landfall on the eastern coast of Florida about five days from now are increasing.
FORECAST MAX WINDS
INIT 28/2100Z 70 KT 80 MPH
12H 29/0600Z 75 KT 85 MPH
24H 29/1800Z 80 KT 90 MPH
36H 30/0600Z 90 KT 105 MPH
48H 30/1800Z 100 KT 115 MPH
72H 31/1800Z 110 KT 125 MPH
96H 01/1800Z 115 KT 130 MPH
Atlantic/2019/09L/Archive/9

Humberto is now a hurricane. Reconnaissance aircraft investigating the cyclone this afternoon found peak flight-level winds of 70kt, with top SFMR winds of 59kt. A blend of these values supports an initial intensity of 60kt. However, the appearance of Humberto continues to improve on satellite, with bursting convection in the northwest quadrant and an eye that has been evident on both visible and infrared channels over the past few hours. This resulted in satellite intensity estimates of T4.0/65kt from SAB and T4.4/75kt from UW-CIMSS ADT. Given the culmination of evidence, the intensity has been raised to 65kt.
The storm's presentation on radar, on satellite, and in recon data suggests the inner core is still materializing. Thus, only steady development is expected in the short term. After 24 hours, the hurricane should continue traversing over 28-29C ocean waters and begin to interact with a trough to its north, resulting in significant pressure falls and outflow expansion. This should set the stage for substantial intensification despite decreasing mid-level relative humidity values, and Humberto is expected to become a major hurricane about 48 hours from now. Peak should occur 12 to 24 hours later. By days 4 and 5, interaction with the trough to the storm's north should mean a sharp increase in wind shear for the storm. It is possible that this interaction may result in Humberto taking on characteristics of an extratropical cyclone, but this phase is expected to be transient and so it does not require explicit mention in the forecast below.
Recon fixes indicate that Humberto has deviated east-southeast today, likely as the storm continues to develop a solid inner core. An eroding mid-level ridge to its east, plus a southward dip in a trough to the system's north, should send Humberto on a northeast track over the next 48 to 60 hours. On days 3 and 4, this trough should cut-off into a mid-level low, and binary interaction between Humberto and that low may send the storm toward the north or northwest. This is a solution that looked unlikely originally but has become increasingly depicted in model guidance. Assuming this is the case, Humberto may pass farther north of Bermuda than originally expected. A turn back toward the north-northeast is expected on day 5 even in most models that send Humberto back toward the west.
FORECAST MAX WINDS
INIT 16/0300Z 65 KT 75 MPH
12H 16/1200Z 70 KT 80 MPH
24H 17/0000Z 80 KT 90 MPH
36H 17/1200Z 90 KT 105 MPH
48H 18/0000Z 100 KT 115 MPH
72H 19/0000Z 105 KT 120 MPH
96H 20/0000Z 90 KT 105 MPH
Atlantic/2019/13L/Archive/10

Lorenzo has explosively intensified since the last advisory. The eyewall replacement cycle hinted at in the 21Z advisory is nearly complete, resulting in the eye clearing out very quickly. While Dvorak estimates from 6Z remain T5.0/90 kt, with a satellite appearance closer to T6.0 this morning, it is clear that the storm has become a major hurricane. Intensity is set, probably conservatively, to 105 kt for this advisory.
Conditions remain very favourable for continued rapid intensification of the hurricane. Internal struggles of the system should be limited over the coming days, since the hurricane is completing an eyewall replacement. Shear is likely to pick up around day 2, resulting in slight weakening. The storm will continue slowly weakening until it crosses the 26C isotherm, which should result in steady weakening around day 5.
The track forecast remains the same since the last advisory. The hurricane is tracking quickly around the periphery of the subtropical ridge to its northeast. By day 3 it will turn northwards into a weakness. The track consensus is very high.

FORECAST MAX WINDS
INIT 26/0900Z 105 KT 120 MPH
12H 26/1800Z 115 KT 130 MPH
24H 27/0600Z 125 KT 145 MPH
36H 27/1800Z 125 KT 145 MPH
48H 28/0600Z 120 KT 140 MPH
72H 29/0600Z 115 KT 130 MPH
96H 30/0600Z 105 KT 120 MPH
Atlantic/2018/04L/Archive/4

Tropical Storm Debby Discussion Number 4

Wiki-Hurricanes Forecast Center

5:00 AM AST Wed Aug 8 2018

Debby has made the transition to a fully tropical cyclone. Satellite imagery shows that the convection that began building south of the center prior to the last advisory has only grown and deepened, now obscuring the low-level circulation. What appears to be a spiral band has also formed in the southern quadrant. The earlier 0z ASCAT pass depicted a tight wind field more associated with tropical cyclones than subtropical cyclones. Finally, a 0356z GMI microwave pass indicated a nearly closed low-level eye-like feature. Given the increase in organization, the initial intensity has been set to 40kt, closest to a satellite estimate of T2.7/39kt from UW-CIMSS ADT.

Debby is moving northward but should make the turn northeast very soon, ahead of an upper-level trough approaching from the west. Models are in good agreement that Debby should be absorbed by this feature in about 36 hours. Before that time, an environment of moderate wind shear, marginal ocean temperatures, adequate moisture, and conditional instability fueled by cooler-than-average upper-level temperatures could allow for slight intensification.

FORECAST POSITIONS AND MAX WINDS

INIT 08/0900Z 40 KT 45 MPH

12H 08/1800Z 45 KT 50 MPH

24H 09/0600Z 40 KT 45 MPH

36H 09/1800Z...DISSIPATED
Atlantic/2019/05L/Archive/44

Dorian is near major hurricane intensity this afternoon. Conventional satellite imagery shows a much healthier tropical cyclone than overnight, with much deeper convection circling the large eye. Two aircraft have been sampling the hurricane recently, finding peak flight-level winds of 110kt. This supports an initial intensity of at least 95kt. The minimum pressure as measured by the most recent dropsonde is 957mb, a drop of 8mb since the last advisory.
Dorian is exhibiting a very healthy poleward outflow channel, evidence of a low wind shear environment. These light upper-level winds combined with the warm waters of the Gulf Stream may work in conjunction to allow Dorian to become a major hurricane again overnight. However, wind shear should increase tomorrow, injecting dry air and kickstarting a weakening trend. Extratropical transition is expected between days 3 and 4 as Dorian races northeastward across the Atlantic.
Recon fixes indicate that Dorian is moving mainly toward the north. A north-northwest to north motion is expected for the next 12 hours as high pressure remains situated off the Southeast United States. Thereafter, an approaching upper-level trough should allow the hurricane to turn northeast and accelerate. On this track, Dorian should come extremely close to the coastline of northeastern South Carolina, and it is likely to brush or make landfall on the eastern coastline of North Carolina. By days 4 and 5, Dorian should affect Nova Scotia and Newfoundland as an extratropical cyclone.
FORECAST MAX WINDS
INIT 04/2100Z 95 KT 110 MPH
12H 05/0600Z 100 KT 115 MPH
24H 05/1800Z 90 KT 105 MPH
36H 06/0600Z 85 KT 100 MPH
48H 06/1800Z 80 KT 90 MPH
72H 07/1800Z 70 KT 80 MPH
96H 08/1800Z 60 KT 70 MPH...POST-TROP/EXTRATROP
Atlantic/2015/02L/Archive/11

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 11

WIKI-HURRICANES FORECAST CENTER

1000PM CDT WED JUN 17 2015

...BILL PRESSES ONWARD TOWARDS THE RED RIVER ...

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

LOCATION... 33.7N 97.3W

ABOUT 65MI... 100KM N OF FORT WORTH, TEXAS

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

MINIMUM BAROMETRIC PRESSURE... 1001 MB...29.56 INCHES

PRESENT MOVEMENT...N AT 4 KT...5 MPH...7 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 1000 pm CDT, the center of Tropical Depression Bill was located at 33.7N, 97.3W, or about 65 miles (100 kilometers) north of Fort Worth, Texas. Maximum sustained winds were 25 knots (30 mph, 50 km/h), with higher gusts. The minimum barometric pressure was 1001 millibars (hPa; 29.56 inHg), and the system was moving northward at 4 knots (5 mph, 7 km/h). Bill is expected to slowly deteriorate into a remnant area of low-pressure as it begins to curve northeastward across the Central and later Eastern United States.

NEXT ADVISORY

Next complete advisory at 400 am CDT.

$$

Forecaster TheAustinMan

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 11

WIKI-HURRICANES FORECAST CENTER

1000PM CDT WED JUN 17 2015

Not much has changed will Bill over the last six hours, with the center now moving slowly towards the Red River. The center is currently weighed more towards the western part of the overall circulation. Heavy rains continue within a large rain shield on the northwestern quadrant of Bill, as opposed to intermittent rainbands on all other sides of Bill. As the circulation remains closed at this time, Bill remains a tropical depression. The intensity remains at 25 knots due to surface observations of sustained winds originally reported around 27 mph. The track forecast remains unchanged as there have been no significant changes to the dominant steering currents, and this advisory is virtually an update of the last. Bill is still expected to gradually deteriorate in organization, but perhaps maintain winds as it traverses northeastward across the eastern United States.

INIT 18/0300Z 33.7N 97.3W 25KT 30MPH

12HR 18/1200Z 34.8N 96.9W 25KT 30MPH

24HR 19/0000Z 35.4N 95.8W 25KT 30MPH

36HR 19/1200Z 36.2N 93.5W 20KT 25MPH ... REMNANT LOW

48HR 20/0000Z 37.0N 90.8W 20KT 25MPH ... REMNANT LOW

72HR 21/0000Z 38.4N 86.0W 20KT 25MPH ... REMNANT LOW

96HR 22/0000Z ... ABSORBED BY FRONTAL SYSTEM

$$

Forecaster TheAustinMan
Atlantic/2019/08L/Archive/14

Gabrielle's convective mass is shrinking on infrared satellite this morning, although its low-level circulation appears more well-defined and it has consolidated near the southeastern edge of the deep convection. The storm's mid-level vortex appears stretched, a result of the strong wind shear it is enduring and the diffluent upper-level pattern. The main bulk of the convection itself is strongly sheared from the east. It is possible that the storm has weakened a bit but the increase in lower-level organization from the center reformation allows for Gabrielle's intensity to be held at 45 kt.
While Gabrielle is still experiencing strong easterly shear, this is forecast to decrease quickly over the next few hours with the TUTT dipping to the southwest away from the storm. This will provide a more favorable environment for intensification with warm sea surface temperatures near 28C, although a fairly dry mid-level environment will remain present. Over the next two and a half days shear will remain moderate, creeping slowly upward, allowing for the storm to intensify steadily. Model guidance has decreased a little this cycle as more shear is forecast. It remains to be seen whether this forecast increase will occur, so the intensity forecast remains much the same for now. On day 3, wind shear skyrockets regardless as the storm approaches a strong jet streak associated with Ex-Dorian. In this strongly baroclinic environment, Gabrielle is expected to transition quickly into an extratropical cyclone by 96h.
Gabrielle continues to move northwest. It should continue on this track southwest of a mid-level ridge located near the Azores. Around the beginning of day 2, the storm will begin to turn north and eventually northeast as an approaching upper-level trough erode this ridge. The storm will then race off toward the northeast as an extratropical cyclone into the open North Atlantic, dissipating near the British Isles.
FORECAST MAX WINDS
INIT 07/0900Z 45 KT 50 MPH
12H 07/1800Z 50 KT 60 MPH
24H 08/0600Z 55 KT 65 MPH
36H 08/1800Z 65 KT 75 MPH
48H 09/0600Z 75 KT 85 MPH
72H 10/0600Z 85 KT 100 MPH
96H 11/0600Z 60 KT 70 MPH...POST-TROP/EXTRATROP
Atlantic/2019/05L/Archive/50

Dorian continues to weaken this morning, with the hurricane's central dense overcast shrinking significantly since the last advisory. It is also becoming increasingly asymmetric with convection weighted toward the north and east. The two most recent aircraft reconnaissance passes have come in with pretty consistent SFMRs supportive of 75 kt with 700 hPa winds varying from a poorly-mixed 100 kt to the most recent north-northeasterly pass finding only 82 kt. Standard 700 hPa to surface reductions agree with SFMR data so Dorian's initial intensity has been lowered to 75 kt, though the pressure has managed to fall slightly to 957 hPa.
Dorian is expected to continue to weaken as wind shear increases as an upper-level trough dips southeast toward the hurricane and dry air becomes further entrained. Although modeling continues to show that as it gains extratropical features in a baroclinic environment, Dorian is expected to actually deepen, a process that may already be occurring now. Winds, though, should slowly weaken.
Dorian continues toward the northeast this morning, passing over the Outer Banks through this morning. The hurricane is expected to accelerate as an approaching trough carries the storm into the mid-latitude westerlies. The transitioning hurricane will approach Nova Scotia around 42h when it is expected to have already become extratropical by the time its center crosses the coast in Canada. The strong extratropical remnants are expected to continue northeast into far eastern Quebec as well as Newfoundland and Labrador on day 3 before turning more toward the east and passing south of Greenland and eventually Iceland near 120h.
FORECAST MAX WINDS
INIT 06/0900Z 75 KT 85 MPH
12H 06/1800Z 75 KT 85 MPH
24H 07/0600Z 70 KT 80 MPH
36H 07/1800Z 70 KT 80 MPH
48H 08/0600Z 65 KT 75 MPH...POST-TROP/EXTRATROP
72H 09/0600Z 55 KT 65 MPH...POST-TROP/EXTRATROP
96H 10/0600Z 40 KT 45 MPH...POST-TROP/EXTRATROP
Atlantic/2019/10L/Archive7

An aircraft reconnaissance plane inside of Jerry has found maximum flight level winds of 70 kt and maximum SFMR winds of 64 kt. This data supports an increase to hurricane strength, with the intensity for this advisory set at 65 kt. Overnight, convection has begun to wrap around the centre in a typical setup for a minimal hurricane. A microwave pass at 12Z suggested hints of an eyewall developing, with recon confirming that the hurricane has a 20 nmi eye open to the south. Although, recently some dry air entrainment took out parts of the western central dense overcast, this is expected to be temporary.
Conditions continue to look favourable for some modest strengthening today before increased shear sets in tonight. The system is fairly small and has a well defined inner core at this time, and SHIPS hints at the possibility of a 24 hour RI period today. While this doesn't seem particularly likely to me, it is hard to rule it out. Tonight higher shear is expected to set in and halt any intensification, and may induce some weakening. Beyond this, the intensity forecast gets tricky as tiny movements in the track forecast have different outlooks. Plenty of intensity models show conditions improving around day 4 for further strengthening, while others are more bearish. Intensity forecast for the most part remains unchanged from the last advisory.
Jerry is continuing his solid west-northwest movement today, and this is expected for another 3 days until a break in the ridge develops to his north pulling him northward. The challenge continues to be the intensity forecast, as a stronger Jerry will be forced further to the southwest by day 4. Track forecast is getting somewhat clearer today though, and it is likely that Jerry is moving northwards by day 5. Jerry should pass north of the Lesser Antilles bringing only tropical storm impacts to some islands.

FORECAST MAX WINDS
INIT 19/1500Z 65 KT 75 MPH
12H 20/0000Z 75 KT 85 MPH
24H 20/1200Z 75 KT 85 MPH
36H 21/0000Z 70 KT 80 MPH
48H 21/1200Z 65 KT 75 MPH
72H 22/1200Z 65 KT 75 MPH
96H 23/1200Z 65 KT 75 MPH
Atlantic/2019/08L/Archive/6

Gabrielle has further organized since the previous advisory, with deep convection expanding over the low-level circulation. A prominent spiral band lies within the northern semicircle, and upper-level outflow is spectacular to the west. An ASCAT pass received literally minutes after the previous advisory indicated peak winds of 42kt. Therefore, the initial intensity is raised to 45kt for this advisory, in line with a satellite intensity estimate of T3.0/45kt from TAFB.
As mentioned this morning, Gabrielle is beginning to interact with the expansive TUTT cell across the North Atlantic. This interaction is a favorable one for now, as evidenced by the perfect poleward outflow channel on water vapor imagery this afternoon. However, over the coming days, this TUTT cell should strip away Gabrielle's anticyclone and impart southwesterly wind shear on the system. This shear is expected to be strongest around 36 to 48 hours from now, which is when the system should be at its weakest. Beyond that time, upper-level winds should become conducive again, although the SHIPS indicates another uptick by the end of the forecast period. A decline in 700-500mb relative humidity values will accompany the first uptick in wind shear, while ocean temperatures are expected to continually increase over the next 5 days. The end result should be a system that may organize further tonight before weakening over the next few days, with the potential for reorganization on days 4 and 5. Aside from the HWRF, though, most models keep Gabrielle a generally weak storm. The updated forecast looks similar to the previous one.
High pressure over Africa, high pressure over the Azores, and a mid-level low over the central Atlantic are working in unison to direct Gabrielle toward the northwest. This motion should continue for the next four days, followed by a turn toward the north on day 5 as Gabrielle rounds the western edge of the ridge over the Azores while simultaneously beginning to interact with the mid-latitude westerlies.
FORECAST MAX WINDS
INIT 04/2100Z 45 KT 50 MPH
12H 05/0600Z 50 KT 60 MPH
24H 05/1800Z 50 KT 60 MPH
36H 06/0600Z 45 KT 50 MPH
48H 06/1800Z 40 KT 45 MPH
72H 07/1800Z 40 KT 45 MPH
96H 08/1800Z 45 KT 50 MPH
Atlantic/2019/05L/Archive/36

Although it remains well-organized on satellite imagery, a combination of oceanic upwelling, continental dry air advection from Florida, and this morning's eyewall replacement cycle, Dorian has weakened substantially from its Category 5 heyday according to data from reconnaissance aircraft. Radar data from Miami and the Bahamas, in addition to an AMSR2 microwave pass at 1842z, show that much of the storm's western periphery has eroded in the last several hours. The aircraft found peak flight level winds of 129 kt and peak SFMR values of 98 kt. These values would imply a blended intensity of about 110 kt, but I have elected to post a higher value of 120 kt based on likely higher values in the unsampled eastern eyewall.
Dorian has been effectively stationary all day today, wobbling towards all cardinal directions at some point in the last 24 hours. This has kept hurricane-force winds across Grand Bahamas for an extended period of time, with major hurricane winds in localized areas. The situation is due to a number of competing factors, but is largely driven by the erosion of subtropical ridge by a shallow shortwave trough now moving off of the Outer Banks. This trough should leave a somewhat persistent weakness for Dorian to begin drifting towards the north later tonight. The departure of the shortwave will allow for ridging over the southern United States to build some, allowing for a slight west-of-north trajectory over the next two days. A diving shortwave currently over Alberta is expected to reinforce the weakness and slingshot Dorian towards the northeast. Given the expected track very near the U.S. East Coast, minor deviations in track could result in a landfall. Dorian is expected to pass within 80 miles of Cape Canaveral and may pass near or over the coasts of North and South Carolina between 72 and 96 hours. Dorian will likely pass over Nova Scotia sometime on day 5, though a landfall has not been explicitly indicated due to uncertainties in timing.
Dorian demonstrated that the Bahamas were a pristine environment for intensification yesterday, but the hurricane cannot both have and eat its cake. By remaining stationary, Dorian has effectively exhausted the usable heat potential of the northern Bahamas and local Gulf Stream, upwelling cooler waters in the region as well as fetching drier air from the North American continent. This should result in prolonged weakening of Dorian, though it should still remain a strong hurricane over the next several days as it progresses up the Eastern Seaboard. Barolcinic processes should begin by day 4 once Dorian becomes increasingly frontal and expansive.

FORECAST MAX WINDS
INIT 02/2100Z 120 KT 140 MPH
12H 03/0600Z 115 KT 130 MPH
24H 03/1800Z 110 KT 125 MPH
36H 04/0600Z 105 KT 120 MPH
48H 04/1800Z 100 KT 120 MPH
72H 05/1800Z 95 KT 110 MPH
96H 06/1800Z 80 KT 90 MPH
Atlantic/2018/02L/Archive/7

Hurricane Beryl Discussion Number 7

Wiki-Hurricanes Forecast Center

5:00 PM AST Fri Jul 5 2018

After an overnight period organization, Beryl has curbed its intensification, at least slightly, this afternoon. The apparent eye on visible channels this morning clouded over after 1400Z and has not yet returned. There could be a whole host of reasons why this occurred, from falling instability due to daytime heating, to a brief burst of easterly mid-level shear, to an entrainment of dry air. These factors were all observed in some form this afternoon. However, even without the eye, Beryl  also managed internally well thus far this afternoon, and may be expanding its circulation some as evident from some of the lower-level cloud motions seen on visible images. Current intensity estimates from SAB and TAFB give T4.0/65kt. Due to internal persistence from this morning as demonstrated in an 1840Z SSMIS microwave pass, the intensity for Beryl has been kept at 70 kt from last advisory.

No changes to the general track idea this afternoon as subtropical ridging and natural northerly ascent from Coriolis deflection keep Beryl on a west to west-northwesterly path. As discussed in the intensity forecast from the last advisory, present conditions for development are favorable for Beryl. An expansive upper trough tracking west north of Beryl is helping to mop up some of the Saharan Air Layer in the area, particularly where the subsident airmass is most heavily concentrated north of the hurricane. The most favorable time for intensification is expected to take place tonight and close to dawn tomorrow as instability increases with sea surface temperatures, shear, and humidity maintaining favorable values. After that point, a combination of TUTT and tradewind shear as well as drying conditions induced by traversing further north will cause Beryl to shrivel some as it approaches the Lesser Antilles Monday morning. Hostile conditions in the eastern Caribbean should continue to degenerate the system thereafter, and dissipation is shown before 96 hours in the intensity forecast.

FORECAST POSITIONS AND MAX WINDS

INIT 06/2100Z 70KT 80MPH

12H 06/0600Z 75KT 85MPH

24H 07/1800Z 80KT 90MPH

36H 07/0600Z 75KT 85MPH

48H 08/1800Z 60KT 70MPH

72H 09/1800Z 45KT 50MPH

96H 10/1800Z ... DISSIPATED
Atlantic/2019/13L/Archive/14

Lorenzo is maintaining intensity as a very powerful category 4 hurricane. The storm continues to look very impressive, and remains a borderline category 5 as of 9Z. Since not much has changed with the structure of the storm for the past 6 hours, nor has the Dvorak suite of intensities changed all that much, intensity remains set at 135 kt.
The CDO has gone slightly ragged and westward outflow is really starting to get compressed, indicating to me that the hurricane should begin to weaken shortly. The eye has yet to really begin to cool, though it is starting to look more ragged. The hurricane is no doubt at maximum potential intensity for this location, a rather rare occurrence especially in this part of the basin. The storm is likely in the worst of the shear for the next couple days, which given how the storm is holding up, its likely to me that the weakening is not likely to be as harsh as was expected. With SSTs beginning to increase later today as well, Lorenzo has legs to remain a powerful hurricane until about day 2. After this, shear is expected to pick up and remain high, leading to steady weakening through the rest of the forecast period.
Lorenzo is moving northwest around the periphery of a ridge to its northeast. This motion should continue for the next day or so before it begins to turn to the north-northeast. This trajectory should bring a strong Lorenzo near the Azores by the end of day 5.

FORECAST MAX WINDS
INIT 27/0900Z 135 KT 155 MPH
12H 27/1800Z 130 KT 150 MPH
24H 28/0600Z 120 KT 140 MPH
36H 28/1800Z 115 KT 130 MPH
48H 29/0600Z 110 KT 125 MPH
72H 30/0600Z 110 KT 125 MPH
96H 01/0600Z 100 KT 115 MPH