recursal/Fanatic-Fandom huggingface dataset:
Atlantic/2018/02L/Archive/12

Subtropical Depression Beryl Discussion Number 12

Wiki-Hurricanes Forecast Center

11:00 PM EDT Sat Jul 14 2018

Beryl is on its deathbed...again. All organized convective activity dissipated after 20Z, leaving behind a well-defined but bare low-level circulation. This appears to be the result of strong 25-30kt wind shear, plus ocean temperatures that have fallen to near 26C. The 0z analysis from TAFB yielded ST2.5/35kt, but raw T-numbers from UW-CIMSS ADT have decreased to near T1.5/25kt. Given the decrease in organization, the initial intensity has been lowered to 30kt. Clearly, the environment is not conducive for further organization, and instead Beryl should degenerate to a remnant area of low pressure within 24 hours, if not much sooner given its current presentation.

The storm is moving north-northeast on the western periphery of a mid-level ridge to its east. This motion should continue for the next several days, in accordance with most reliable model guidance. The remnants of Beryl may affect Newfoundland by the middle of the week, but this is not expected to be a significant story, with minor effects at best.

FORECAST POSITIONS AND MAX WINDS

INIT 15/0300Z 30 KT 35 MPH...SUBTROPICAL DEPRESSION

12H 15/1200Z 30 KT 35 MPH...POST-TROP/REMNT LOW

24H 16/0000Z 25 KT 30 MPH...POST-TROP/REMNT LOW

36H 16/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW

48H 17/0000Z 25 KT 30 MPH...POST-TROP/REMNT LOW

72H 18/0000Z...DISSIPATED
Atlantic/2019/01Q/Archive/4

Tropical Storm Iba Discussion Number 4

Wiki-Hurricanes Forecast Center

12:00 PM AST Sun Mar 24 2019

Iba has continued to organize over the late-morning hours and has transitioned into a classical curved band system. Compared to yesterday, the storm's center of circulation has become better embedded within the convective envelope, and a convective bulb of -70C and cooler cloud tops has persisted over the center and continues to do so. The prominent spiral band from the overnight hours has remained in place, and additional banding is developing in the storm's northeastern and southeastern quadrants. Cirrus-band satellite imagery from GOES-16 shows a strengthening equatorward outflow channel while the subtropical jet stream to Iba's south is aiding with poleward upper-air transport. This favorable ventilative environment is supported by a co-aligned upper-level anticyclone resulting in modest wind shear of 10 knots. At 12Z, SAB estimated T1.5/30 kt for the intensity, but an 1130z ASCAT-B pass showed a small region of 35 kt winds and my own Dvorak analysis on a 0.4 spiral band is in concurrence. An ASCAT-A pass showed a region of 40 kt winds at the same time, though the circulation was somewhat elongated along a NW-SE axis. Given the size of the maximum wind region, the intensity of Iba is estimated at 40 kt with a central pressure of 1007 mb derived from KZC estimates.

Conditions remain locally favorable for continued intensification over warm ocean waters in excess of 28C. The GFS and ECMWF-IFS both show gradual intensification within these conditions for at least the next two days to a moderate tropical storm, though Iba has thus far exceeded the global intensity guidance. The upper-level anticyclone incubating Iba is expected to move westward over Brazil which could expose Iba to a rather dry layer maximized around 400 mb evident on water vapor imagery to the system's southwest and as depicted on the GFS beginning Tuesday. This should bring column-averaged relative humidity values down to a marginal 60%. Still, anomalously warm sea surface temperatures and divegent flow aloft could attenuate inhibatory effects the system out to about the day 4 timeframe. The current forecast shows continued intensification over the next two days before stabilizing and weakening thereafter as the system encounters a breaking trough, increasing wind shear as the system is pulled towards the southeast. The intensification phase has been increased though the weakening phase retains the pace from the previous advisory.

FORECAST MAX WINDS

INIT 24/1500Z 40 KT 45 MPH

12H 25/0000Z 45 KT 50 MPH

24H 25/1200Z 50 KT 60 MPH

36H 26/0000Z 50 KT 60 MPH

48H 26/1200Z 40 KT 45 MPH

72H 27/1200Z 35 KT 40 MPH

96H 28/1200Z 30 KT 35 MPH...POST-TROP/REMNT LOW

120H 29/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW
Atlantic/2019/10L/Archive/9

Jerry has become an intense Category 2 hurricane this evening. Conventional satellite animations show that deep convection rotated upshear after the previous advisory, featuring persistent lightning activity within the northwestern eyewall. An Air Force reconnaissance aircraft has made two passes through the center, finding a central pressure steady around 975mb right now. The flight also revealed peak flight-level winds of 97kt and maximum SFMR winds around 95kt. Thus, the initial intensity is set to 95kt.
Deep convection continues to persist in the northwestern eyewall, and wind shear is not expected to increase substantially until tomorrow morning. Therefore, although not explicitly mentioned, it would not be surprising if Jerry briefly became a major hurricane. Tomorrow and for the three subsequent days, however, the cyclone is expected to be plagued by hostile upper-level winds and extremely dry air that should result in significant weakening. Jerry is expected to fall to moderate tropical storm intensity by 48 hours. As the cyclone curves northward into a low wind shear environment, re-intensification is expected. The updated intensity forecast is similar to the previous one.
Potent mid-level ridging to the northeast of Jerry is directing the cyclone on a steady west-northwest course. This trajectory should continue for an additional 36 to 48 hours before Jerry reaches the western edge of this ridge and interacts with an upper-level trough, sending the cyclone toward the north and north-northeast. Jerry is expected to be very near Bermuda about 5 days from now.
FORECAST MAX WINDS
INIT 20/0300Z 95 KT 110 MPH
12H 20/1200Z 90 KT 105 MPH
24H 21/0000Z 75 KT 85 MPH
36H 21/1200Z 60 KT 70 MPH
48H 22/0000Z 45 KT 50 MPH
72H 23/0000Z 50 KT 60 MPH
96H 24/0000Z 60 KT 70 MPH
Atlantic/2019/13L/Archive/2

Tropical Depression 13 has strengthened slightly overnight, enough to be named Lorenzo. Dvorak consensus is rather unanimous at T2.5/35 kt, setting the initial intensity for this advisory.
The low level centre of Lorenzo is not quite vertically stacked with the mid level further south. This internal struggle should be pretty easily resolved given the favourable conditions, but should put a bit of a damper on intensification today. After this, all seems should be a go once Lorenzo develops a solid inner core. Shear will be light, SSTs warm and embedded in a moist airmass with little dry air around. Most of the intensity models show Lorenzo attaining hurricane strength by day 2, with continued intensification after that. The intensity forecast is similar to the previous. Lorenzo will move steadily around the subtropical ridge for the next 4 days. Then the storm is expected to turn towards the northwest into a weakness by day 5. While the storm is certainly near the Cabo Verde islands this morning, it should pass well south and bring minimal impacts to them.

FORECAST MAX WINDS
INIT 23/1500Z 35 KT 40 MPH
12H 24/0000Z 40 KT 45 MPH
24H 25/1200Z 50 KT 60 MPH
36H 25/0000Z 60 KT 70 MPH
48H 25/1200Z 70 KT 80 MPH
72H 26/1200Z 85 KT 100 MPH
96H 27/1200Z 100 KT 115 MPH
Atlantic/2019/05L/Archive/32

Dorian struck the Abacos Islands shortly after 16:30z as a catastrophic and extremely intense Category 5 hurricane. Peak flight-level winds before landfall topped 161kt, with numerous SFMR values of 170-175kt. A blend of these values supported a 160kt landfall. An Air Force plane made one final pass through the eyewall of Dorian right at landfall, finding a similar pressure and unchanged winds. Thus, the initial intensity remains 160kt for this advisory.
Radar out of the Bahamas suggested the formative stages of an eyewall replacement cycle this morning, but the outer bands that were suggestive of this process broke apart shortly thereafter. The inner core of Dorian remains extremely stable and very intense. In the presence of low wind shear, very warm ocean temperatures, increasing oceanic heat content, and a moist environment, Dorian is expected to maintain Category 5 intensity for the next 24 to 36 hours. Beyond that time, as the hurricane continues to crawl across the northwestern Bahamas and southwestern Atlantic, its circulation may induce cold water upwelling. Even if water temperatures decrease from 29-30C to around 27C, this has implications for the maximum potential intensity. Thus, slow weakening is expected. A quicker rate of weakening should occur on days 3 through 5 as dry air and wind shear become more prevalent.
Dorian is slowing down as it moves westward. Little deviation in this direction is expected over the next day as high pressure north of the cyclone remains stout. After tomorrow, an upper-level trough over the United States should erode the western periphery of this ridge, allowing Dorian to curve toward the north. The strength and timing of the ridge, the trough, and the hurricane will all affect whether Dorian curves barely offshore or whether it strikes the eastern coastline of Florida, and whether the system barely misses North Carolina or strikes the state as well. There have been small shifts west and east varying by model and run, but it does appear increasingly possible that the eye of Dorian clips at least the Outer Banks of North Carolina by day 5, and the new forecast accounts for that possibility. The bottom line is that Dorian remains an extreme threat to the Southeast United States.
FORECAST MAX WINDS
INIT 01/2100Z 160 KT 185 MPH
12H 02/0600Z 155 KT 180 MPH
24H 02/1800Z 145 KT 165 MPH
36H 03/0600Z 135 KT 155 MPH
48H 03/1800Z 125 KT 145 MPH
72H 04/1800Z 105 KT 120 MPH
96H 05/1800Z 90 KT 105 MPH
Atlantic/2019/01Q/Archive/11

Tropical Storm Iba Discussion Number 11

Wiki-Hurricanes Forecast Center

6:00 AM AST Tue Mar 26 2019

If there was any question of whether the window for intensification has closed, the satellite presentation of Iba tonight highlights the answer. Unlike the past two nights, deep convection has not continued to expand through the diurnal maximum. In fact, ever-increasing westerly wind shear is shearing this convection well east of the exposed low-level circulation. Multiple vortices of a broader gyre appear evident on the shortwave infrared imagery. Given the decrease in organization since the previous advisory, when the ScatSat pass only showed one 40kt barb, the initial intensity has finally been changed to 35kt.

Wind shear is only expected to increase over the next day as Iba finds itself embedded within a strong westerly jet stream. These strong upper-level winds will also inject very dry mid-level air into the storm's circulation, limiting convective potential. Therefore, a rapid spin-down is expected. Iba is expected to degenerate to a non-convective remnant area of low pressure in 36 hours now, with dissipation by day five; it is possible this dissipation could occur sooner. Iba is expected to drift south over the next day before meandering east.

FORECAST MAX WINDS

INIT 26/0900Z 35 KT 40 MPH

12H 26/1800Z 35 KT 40 MPH

24H 27/0600Z 30 KT 35 MPH

36H 27/1800Z 30 KT 35 MPH...POST-TROP/REMNT LOW

48H 28/0600Z 25 KT 30 MPH...POST-TROP/REMNT LOW

72H 29/0600Z 20 KT 25 MPH...POST-TROP/REMNT LOW

96H 30/0600Z 15 KT 20 MPH...POST-TROP/REMNT LOW

120H 31/0600Z...DISSIPATED
Atlantic/2019/12L/Archive/12

Karen continues to fire generally organized convective activity. However, the storm's low-level circulation is broad and generally weak, in addition to being displaced northeast of the convection. An Air Force reconnaissance aircraft struggled to find winds of tropical storm force at flight-level, much less at the surface, but an ASCAT pass this morning showed winds of 40kt occurring in the convection. Given the discrepancy here, the initial intensity is left unchanged at 35kt.
Wind shear is expected to increase in 36 to 48 hours, outweighing the warm ocean temperatures and light upper-level winds Karen is positioned in right now. Additionally, mid-level relative humidity values are expected to continue falling. Thus, degeneration to a remnant low is expected about 48 hours from now, with dissipation still anticipated by day 4.
Karen is moving steadily north-northeast, but a bend toward the east and then a very sharp retraction to the west is expected by the weekend as high pressure builds across the western Atlantic.
FORECAST MAX WINDS
INIT 26/2100Z 35 KT 40 MPH
12H 27/0600Z 30 KT 35 MPH
24H 27/1800Z 30 KT 35 MPH
36H 28/0600Z 25 KT 30 MPH
48H 28/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 29/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2018/03L/Archive/12

Hurricane Chris Discussion Number 12

Wiki-Hurricanes Forecast Center

11:00 PM EDT Tue Jul 10 2018

Chris has intensified further since the previous advisory, with a warm and symmetric eye surrounded by deep convection. Satellite intensity estimates range from T4.5/77kt from TAFB, to T5.0/90kt from SAB and SATCON, to T5.4/99.6kt from UW-CIMSS ADT. Erroneous analysis from TAFB likely led to an unrealistically low estimate, whereas UW-CIMSS ADT is well known to run a bit high for strong hurricanes. In addition, some dry air has limited the eastward extent of the most intense eyewall convection over the past few hours. As such, the initial intensity is set at 90kt line with SAB and SATCON. The hurricane is moving northeast, and this trajectory should continue at an accelerated rate over the next day as it interacts with a trough moving southward. Chris should pass just southeast of Newfoundland in about two days, though periphery effects are still likely there.

Outside of temporary dry air intrusions like we are seeing now, the environment remains ideal for further strengthening. In fact, interaction between Chris and the upper-level trough to its north is just now beginning; this feature should act as a sink that allows for further pressure falls today as the hurricane continues over waters near 27C. The large diameter of the eye suggests that internal core changes are not inherently likely or imminent, and so the stage appears set for gradual intensification over the next 24 hours. Thereafter, Chris is expected to transition to an extratropical cyclone as it enters frigid waters and more wholly interacts with the trough.

FORECAST POSITIONS AND MAX WINDS

INIT 11/0300Z 90 KT 105 MPH

12H 11/1200Z 95 KT 110 MPH

24H 12/0000Z 100 KT 115 MPH

36H 12/1200Z 90 KT 105 MPH

48H 13/0000Z 65 KT 75 MPH

72H 14/0000Z 45 KT 50 MPH...POST-TROP/EXTRATROP

96H 15/0000Z...DISSIPATED

120H 16/0000Z...DISSIPATED
Atlantic/2019/09L/Archive/4

Humberto continues to intensify this afternoon, with a much better organized low-level circulation, expanding upper-level outflow, and an expansion in deep convection over the center. The reconnaissance plane earlier this afternoon found peak flight-level winds just under 50kt with maximum SFMR values between 40-45kt. Therefore, the initial intensity is raised to 45kt, and it is possible this is conservative given satellite trends since that time.
The expansion in outflow is indicative of a more favorable wind shear pattern. Upper-level winds are expected to remain conducive for the next 4 days before an uptick in shear on day 5 as Humberto interacts with a cut-off low positioned offshore New England. Water temperatures will remain sufficient through the entire period, while mid-level relative humidity values become gradually less conducive after day 3. Therefore, the intensity forecast has been tweaked a bit to show a quicker rate of strengthening in the short term, as well as a sooner peak with weakening on day 5.
Humberto continues to move north-northwest this evening. A turn toward the north is expected tonight, followed by an acceleration to the north-northeast on Monday and beyond as Humberto interacts with the mid-latitude westerlies. Dynamical guidance is in extremely good agreement regarding the path of the hurricane, and a close shave by Bermuda around day 4 looks likely. The certainty regarding Humberto's track becomes a lot less clear when viewing ECMWF ensemble guidance, with a sizable number of members indicating a turn toward the west as high pressure builds in behind the mid-level trough. This solution does not look likely right now, but it is something to watch over coming days.
FORECAST MAX WINDS
INIT 14/2100Z 45 KT 50 MPH
12H 15/0600Z 55 KT 65 MPH
24H 15/1800Z 65 KT 75 MPH
36H 16/0600Z 75 KT 85 MPH
48H 16/1800Z 85 KT 100 MPH
72H 17/1800Z 95 KT 110 MPH
96H 18/1800Z 100 KT 115 MPH
Atlantic/2019/08L/Archive/12

Gabrielle has regenerated into a tropical cyclone. Conventional satellite imagery shows a significant uptick in organized, deep convection, even though this convection is still wholly displaced north of the low-level circulation due to the effects of wind shear that were ongoing last time Gabrielle was a tropical storm. A partial ASCAT pass around 12z showed peak winds of 37kt. Given that fact, plus a satellite intensity estimate of T3.0/45kt from UW-CIMSS ADT, I have decided to set the initial intensity at 40kt.
Latent heat release from Gabrielle's convection is interacting with the expansive TUTT cell across the North Atlantic. This continued interaction should cause the TUTT to split into a broad upper-level trough northeast of the cyclone, as well as a westward-moving cut-off low to the west of Gabrielle. Sandwiched inbetween these two features, Gabrielle should be able to develop an upper-level anticyclone, with two fantastic outflow channels established between 36 to 48 hours from now. Ocean temperatures are currently in the process of rising and should near 30C about 36 hours from now, a testament to how anomalously warm the subtropical Atlantic is this year. The only less-than-ideal parameter is 700-500mb relative humidity, with those values settling around 45 percent. Still, in the presence of low wind shear, dry air entrainment is only expected to be a transient issue. Model guidance as a whole has become more bullish since Gabrielle was last a tropical cyclone, but there is still variance. The ECMWF shows little further development, the SHIPS and LGEM are focused around a strong tropical storm or minimal Category 1 hurricane, the GFS foresees a Category 2 hurricane, and the HWRF/HMON models have a storm near major hurricane intensity. Given the conditions in place, I certainly find it necessary to place more weight on the upper-end solutions, and the new forecast shows Gabrielle becoming a Category 2 hurricane around day 3. Extratropical transition is expected on day 5 as Gabrielle enters frigid waters and interacts with non-tropical features.
Gabrielle is moving toward the northwest this afternoon and should continue to do so for the next few hours as it remains on the southwest edge of high pressure over the Azores. Between 12 and 36 hours, this ridge is expected to strengthen further and force Gabrielle on a west-northwesterly course. By days 2 through 5, the influence of an upper-level trough and the extratropical remnants of now-Hurricane Dorian should curve the cyclone north and northeast at an accelerating rate. Model guidance is in amazingly good agreement regarding Gabrielle's track.
FORECAST MAX WINDS
INIT 06/2100Z 40 KT 45 MPH
12H 07/0300Z 45 KT 50 MPH
24H 07/1200Z 50 KT 60 MPH
36H 08/0000Z 60 KT 70 MPH
48H 08/1200Z 70 KT 80 MPH
72H 09/1200Z 85 KT 100 MPH
96H 10/1200Z 75 KT 85 MPH
Atlantic/2019/07L/Archive/4

Fernand remains a sheared tropical cyclone this morning. Satellite presentation remains similar with deep convection displaced to the northwest of the low level center. Since the last advisory time, this displacement has increased a bit. As a result, the storm's initial intensity remains 45 kt.
Conditions really have only one factor hampering a very favorable environment and that is the wind shear. Wind shear remains a relatively strong 20 kt, but it is expected to decrease a little before Fernand makes landfall. Whether that will be enough to allow the storm to intensify over nearly 30C waters in an environment of high mid-level humidity is uncertain. So long as the storm maintains this sheared structure with deep convection displaced increasingly further from the center, intensification will be minimal and it is running out of time. Once the storm reaches the coast, weakening is expected to be swift as the mountainous terrain of Mexico disrupts the circulation.
The storm is moving west slowly and it should move generally west-northwest under the influence of a ridge over the southwestern United States until it makes landfall in about 12 hours in Tamaulipas.
FORECAST MAX WINDS
INIT 04/0900Z 45 KT 50 MPH
12H 04/1800Z 50 KT 60 MPH
24H 05/0600Z 30 KT 35 MPH...INLAND
Atlantic/2019/01Q/Archive/18

Tropical Storm Iba Discussion Number 18

Wiki-Hurricanes Forecast Center

12:00 AM AST Thu Mar 28 2019

Iba is refusing to die this evening. Recent satellite images show a system characterized with a partially exposed low-level circulation but persistent deep convection to the southeast. This is an impressive feat considering upper-level winds have increased to over 25kt, helping to impart mid-level dry air—with relative humidity values under 50 percent—into the center. Although SAB only analyzed a T1.5/25kt at 0z, a ScatSat pass from around that time, surprisingly, showed maximum winds have increased to near 40kt. So, against all odds, that is the initial intensity used for this advisory.

Although Iba has been a persistent little fella over the past 24 hours, I have no choice but to continue forecasting its quick demise. It should be noted that a combination of visible and shortwave infrared animations show that the low-level circulation is becoming increasingly elongated. I have prolonged Iba's transition to a non-convective remnant area of low pressure to 24 hours from now based on the storm's tenacity; an alternate scenario is that the low-level circulation becomes too elongated to meet the definition of a tropical cyclone. This could plausibly occur at any point as Iba drifts east. Dissipation is expected in about three days.

FORECAST MAX WINDS

INIT 28/0300Z 40 KT 45 MPH

12H 28/1200Z 35 KT 40 MPH

24H 29/0000Z 30 KT 35 MPH...POST-TROP/REMNT LOW

36H 29/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW

48H 30/0000Z 20 KT 25 MPH...POST-TROP/REMNT LOW

72H 31/0000Z...DISSIPATED
Atlantic/2019/08L/Archive/10

Gabrielle has not become any better organized this afternoon, with an exposed and elongated center far, far removed from associated convection. This has been the case since around 10z, so if convection does return before the issuance of the next advisory, it is likely that Gabrielle will be designated a post-tropical cyclone. The initial intensity is held at 40kt given the earlier ASCAT data. Upper-level winds over 20kt are affecting Gabrielle, and similar values are expected over the next 36 hours as the system interacts with a TUTT cell across the North Atlantic. Beyond that time, a sharp decrease in wind shear is likely. This drop will be accompanied by an increase in ocean temperatures and a leveling off in declining mid-level relative humidity values. Thus, re-intensification (and/or regeneration) is likely to occur beginning on day 2. Global model guidance is more bullish with Gabrielle today, and the SHIPS/LGEM suggest organization as well. The HWRF continues to lie on the upper-end of the guidance with a Category 2 hurricane. Thus, the updated forecast remains similar to the last one, except to introduce temporary degeneration in the short term.
As mentioned in all previous advisories, Gabrielle is moving steadily northwest thanks to high pressure centers over the Azores and Africa, as well as a mid-level low over the central Atlantic. A northwesterly motion should continue for the next 72 hours before Gabrielle curves north and northeast in advance of an upper-level trough. Models are in excellent agreement regarding this scenario.
FORECAST MAX WINDS
INIT 05/2100Z 40 KT 45 MPH
12H 06/0600Z 35 KT 40 MPH...POST-TROP/REMNT LOW
24H 06/1800Z 35 KT 40 MPH...POST-TROP/REMNT LOW
36H 07/0600Z 35 KT 40 MPH...POST-TROP/REMNT LOW
48H 07/1800Z 40 KT 45 MPH
72H 08/1800Z 45 KT 50 MPH
96H 09/1800Z 55 KT 65 MPH
Atlantic/2019/13L/Archive/20

Reorganization continues this afternoon in association with powerful Hurricane Lorenzo, with the overall system becoming better-defined. Lorenzo possesses a large eye that has been becoming increasingly warm and clear on infrared satellite imagery, with a robust eyewall in the northeast quadrant as observed on microwave scans at 1600z and 1741z. There does not appear to be any immediate signs of significant structural change with the core structure. The NOAA3 "Miss Piggy" reconnaissance aircraft arrived at the hurricane this afternoon and found peak flight-level winds of 126kt and estimated surface winds of 112kt. Dropsondes indicated low-level averages of 108kt. Based on all of this data, the intensity has been increased to 115kt.
The track forecast remains the same as Lorenzo pulls northward in response to a broad steering weakness in the subtropical ridge. By day 3, the storm should begin taking a more northeasterly path as it connects with the jet stream, likely cutting a path through the western Azores at day 4. Strong, life-threatening winds are anticipated throughout the islands as the storm passes through. Lorenzo is entering a slightly unfavorable region for wind shear, but thus far its convective activity has reduced negative impacts. However, some weakening or stabilization is expected to take place tomorrow before favorable conditions come into alignment at 2-3 days. Most of the guidance shows intensification within this window, Extratropical transition is anticipated during and after Lorenzo passes through the Azores.
FORECAST MAX WINDS
INIT 28/2100Z 115 KT 130 MPH
12H 29/0600Z 120 KT 140 MPH
24H 29/1800Z 110 KT 125 MPH
36H 30/0600Z 105 KT 110 MPH
48H 30/1800Z 105 KT 120 MPH
72H 01/1800Z 110 KT 125 MPH
96H 02/1800Z 85 KT 100 MPH...POST-TROP/EXTRATROP
Atlantic/2019/06L/Archive/9

Erin has failed to develop deep convection near its low-level circulation this afternoon, despite decreasing upper-level winds. ASCAT data from earlier showed a wide swath of 30-31kt winds east of the center. Given both of those facts, the initial intensity has been decreased to 30kt, and Erin has been downgraded to a tropical depression. The reprieve in shear is expected to be brief, and given the system's continuous struggles as is, no further intensification is expected. Instead, extratropical transition should occur about 24 hours from now, although degeneration to a remnant low could occur sooner if convection does not develop closer to the center. Erin is accelerating northward this afternoon, with a curve toward the north-northeast of northeast expected tomorrow in advance of an upper-level trough. This should bring the system across Nova Scotia and Newfoundland.
FORECAST MAX WINDS
INIT 28/2100Z 35 KT 40 MPH
12H 29/0600Z 35 KT 40 MPH
24H 29/1800Z 30 KT 35 MPH...POST-TROP/EXTRATROP
36H 30/0600Z 30 KT 35 MPH...POST-TROP/EXTRATROP
48H 30/1800Z 30 KT 35 MPH...POST-TROP/EXTRATROP
WFC вики

На данный момент создано 21 статья, и вы **можете помочь нам**

**Wikia** — это сообщество интернет-энциклопедий на разные темы. Любой пользователь может редактировать страницы на этой Вики. Просто нажмите кнопку «Править» в верхней части любой страницы!

Посетите Вики Сообщества и задайте любой вопрос на центральном форуме.

Напишите здесь о чём эта Вики, сделайте ссылки на основные разделы Вики. Добавьте описание вики. Читатели и участники этой Вики должны знать, о чём она.

 Файл:Placeholder

Вы можете улучшить эту вики! Создайте свою статью.
<createbox>
width=24
break=no
buttonlabel=Создать новую страницу
</createbox>
Так же вы можете улучшать уже созданные страницы.
Atlantic/2019/02L/Archive/19

While the development of some convection near the center of circulation last night delayed a reclassification of Barry to a remnant low, it's clear that this transition should occur inevitably sometime today. RAP analyses indicated that the fluid trapping parameter has risen to near zero this morning, with low-level moisture transport no longer directing moist air towards the center of circulation over Western Arkansas. Surface observations indicate Barry possesses winds no stronger than 20 kt. Barry and its remnants are expected to trend towards the north-northeast to northeast over time before opening up into a trough in the latter half of tomorrow.
FORECAST MAX WINDS
INIT 15/1200Z 20 KT 25 MPH...INLAND
12H 16/0000Z 15 KT 20 MPH...POST-TROP/REMNT LOW
24H 16/1200Z 15 KT 20 MPH...POST-TROP/REMNT LOW
Atlantic/2019/07L/Archive/3

Fernand is a tale of two cyclones this evening. On one hand, the low-level circulation is completely exposed east of its associated convection. On the other hand, this thunderstorm activity is quite well organized, and a reconnaissance aircraft found a much stronger storm than expected. Flight-level winds maxed out at 51kt with peak SFMR values of 49kt. A blend of these values supports upping the initial intensity to 45kt. Fernand only has less than 24 hours before landfall. However, environmental conditions are expected to favor some organization during that time, and I have raised the peak intensity to 55kt. If shear relents even a little, this forecast may verify too low. Quick dissipation is expected once the system moves into the mountainous terrain of northern Mexico.
Recon fixes indicate that the center of Fernand is basically stationary. However, high pressure over the Southwest United States is likely to force the cyclone west-northwest into the coastline in about 18 hours.
FORECAST MAX WINDS
INIT 04/0300Z 45 KT 50 MPH
12H 04/1200Z 55 KT 65 MPH
24H 05/0000Z 35 KT 40 MPH...INLAND
Atlantic/2019/02L/Archive/8

Barry has continued to intensify this afternoon. An aircraft reconnaissance plane found peak flight-level winds of 73kt, with believable surface winds of 56kt. A blend of these values supports a comfortable 55kt. This is despite Barry's current presentation on satellite, which continues to feature a broad low-level circulation displaced north of the deep convection. Several mesovortices continue to rotate within the gyre, sometimes diving into convection and amplifying vorticity, allowing surface pressures to fall and winds to increase. There has been some consolidate of the low during the day today, and it would not be too surprising if the low-level circulation becomes obscured for once tonight.
Although the official forecast continues to call for a 60kt peak and landfall intensity, there is still a narrow window of time for Barry to become a Category 1 hurricane. Its best chance may be right at landfall, when friction from its interaction with land may produce a tighter low-level center. Regardless, slow weakening is expected immediately following landfall, with more rapid degradation as the storm moves away from the marshes of Louisiana. Dissipation is expected on day 5, though this could occur a little sooner.
The short-term motion of Barry continues to fluctuate wildly thanks to the mesovortices within its broad center, but the long-term trajectory is toward the west-northwest. A curve toward the northwest should occur tonight, bringing the cyclone to a landfall point just east of Marsh Island. A turn toward the north into a weakness in high pressure is expected by Sunday, with a recurve east into the mid-latitude westerlies thereafter.
FORECAST MAX WINDS
INIT 12/2100Z 55 KT 65 MPH
12H 13/0600Z 60 KT 70 MPH
[N/A 13/1200Z 60 KT 70 MPH...LANDFALL]
24H 13/1800Z 45 KT 50 MPH...INLAND
36H 14/0600Z 35 KT 40 MPH...INLAND
48H 14/1800Z 25 KT 30 MPH...INLAND
72H 15/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 16/1800Z 15 KT 20 MPH...POST-TROP/REMNT LOW
Atlantic/2019/02L/Archive/7

Although still largely disorganized, Barry is in the process of organizing into a more conventional sheared tropical cyclone structure this morning, undoubtedly aided by convective growth during diurnal maximum. The convection is more robust near the exposed low-level center of circulation this morning compared to the overnight, though the entire cirrus canopy remains limited to an arc encompassing the southern semicircle of the circulation. Barry's strongest winds are localized in an arc roughly 40 miles east of the center of circulation. A US Air Force Reserve aircraft investigating the storm found peak flight level winds of 61 kt and numerous SFMR values of 48-54 kt in this band, though rain contamination was possible across the strong band. Based on these values, Barry's initial intensity is set to 50 kt.
Barry has crept slowly westward for most of its life, and this morning appears to be perfectly content with remaining quasi-stationary. However, the marginal ridge weakness created by the trough over the Eastern United States should provide a window for Barry to begin drifting towards the northwest today, in the general direction of Vermillion and Cote Blanche Bays. Models are tightly clustered with regard to this forecast depiction, and landfall is anticipated close to dawn tomorrow in that area. Once inland, Barry is expected to continue northwards through Louisiana and accelerate and trend northeast over time as low-level ridging brings Barry and its future remnants towards the polar jet stream.
Conditions have improved marginally since last night with satellite imagery noting a decrease in dry air over the northern Gulf of Mexico. Ocean temperatures and effective wind shear values are generally supportive of intensification, though the northerly upper-level winds from a nearby upper-level ridge and Barry's own outflow are still in a gridlock with one another. High-resolution short-term model guidance suggests that we'll see improvements to Barry's convective structure throughout the afternoon, which will make the storm at least somewhat more receptive of environmental favorables. Although an eyewall of even the most rudimentary sort appears unlikely, the guidance anticipates that the circulation may finally tuck under convection tonight. However, Barry has limited time - less than a day - before it begins to track onto the coast. Some additional strengthening is depicted in the forecast before landfall, and hurricane intensity remains a possibility. Weakening should occur once over land with degeneration to a remnant low depicted in approximately three days.

FORECAST MAX WINDS
INIT 12/1500Z 50 KT 60 MPH
12H 13/0000Z 55 KT 65 MPH
24H 13/1200Z 60 KT 70 MPH...LANDFALL
36H 14/0000Z 45 KT 50 MPH...INLAND
48H 14/1200Z 30 KT 35 MPH...INLAND
72H 15/1200Z 25 KT 30 MPH...POST-TROP/REMNT LOW
96H 16/1200Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic/2018/04L/Archive/6

Tropical Storm Debby Discussion Number 6

Wiki-Hurricanes Forecast Center

5:00 PM AST Wed Aug 8 2018

Debby is being affected by about 15kt of wind shear and now moving over ocean temperatures around 25C. As a result, the low-level circulation is becoming elongated and the associated convection is beginning to lose organization. Satellite intensity estimates were T1.5/25kt from SAB and T2.7/39kt from UW-CIMSS ADT. An earlier ASCAT showed peak winds around 35kt, and that is the initial intensity used for this advisory. Debby is moving northeast ahead of an upper-level trough and should continue on this path until the trough causes the tropical cyclone to open up into a trough in about 36 hours.

MAXIMUM WINDS FORECAST

INIT 08/2100Z 35 KT 40 MPH

12H 09/0600Z 30 KT 35 MPH

24H 09/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW

36H 10/0600Z...DISSIPATED
Atlantic/2015/02L/Archive/8

## Public advisory

TROPICAL DEPRESSION BILL ADVISORY NUMBER 8

WIKI-HURRICANES FORECAST CENTER

0400AM CDT WED JUN 17 2015

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

LOCATION... 31.3N 97.2W

ABOUT 60MI... 95KM NNE OF AUSTIN, TEXAS

MAXIMUM SUSTAINED WINDS...30 KT...35 MPH...55 KM/H

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

PRESENT MOVEMENT...N AT 15 KT...18MPH...28 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 0400 am CDT, the center of Tropical Depression Bill was located at 31.3N, 97.2W, or about 60 miles (95 km) north-northeast of Austin, Texas. Maximum sustained winds were 30 knots (35 mph, 55 km/h), with higher gusts. The minimum barometric pressure was 1000 millibars (hPa; 29.53 inHg), and the system was moving towards the north at 15 knots (18 mph, 28 km/h). Bill is expected to curve around a subtropical ridge and slowly weaken over the next two days, passing near the Dallas-Forth Worth metropolitan area before curving eastward towards the Ozarks.

NEXT ADVISORY

Next complete advisory at 1000 am CDT.

$$

Forecaster Kalassak

## Discussion

TROPICAL DEPRESSION BILL DISCUSSION NUMBER 8

WIKI-HURRICANES FORECAST CENTER

0400AM CDT WED JUN 17 2015

Bill has been downgraded to a tropical depression this morning as the overall storm structure is beginning to change with convection mainly displaced to the north of the center and curving out east. Radar data indicate the storm's structure is beginning to appear slightly more like an extratropical system as the storm traverses further inland and its core restructures. As a result, Bill's intensity is now 30 knots.

There is a very solid model consensus on the future track of Bill over the United States, and this forecast continues to follow it. Bill is expected to travel north into Oklahoma in around 18 hours before it begins a recurve to the east around the subtropical ridge. Models continue to indicate that Bill's intensity will decrease relatively slowly throughout the rest of its life. Overally, only slight changes have been made to the current forecast track and intensity aside from adjustments based on a more rapid forward motion since the last advisory.

INIT 17/0900Z 31.3N 97.2W 30KT 35MPH

12HR 17/1800Z 32.8N 97.4W 25KT 30MPH

24HR 18/0600Z 34.5N 96.7W 25KT 30MPH

36HR 18/1800Z 36.7N 95.5W 20KT 25MPH ... REMNANT LOW

48HR 19/0600Z 37.3N 93.7W 20KT 25MPH ... REMNANT LOW

72HR 20/0600Z 38.5N 89.4W 20KT 25MPH ... REMNANT LOW

96HR 21/0600Z 41.2N 80.0W 15KT 20MPH ... REMNANT LOW

120HR 22/0600Z ... MERGED WITH EXTRATROPICAL CYCLONE

$$

Forecaster Kalassak
Atlantic/2019/12L/Archive/9

Karen is not looking so great this afternoon. While shear and moisture remains favourable, it's becoming clear that the storm cannot resist the low-level divergent steering flow that is not allowing convection to easily persist. Karen has not been able to fire off any significant convective bursts since this morning and the circulation is nearly exposed. Aircraft reconnaissance is in the system and has found enough evidence to keep intensity at 35 kt for this advisory.
Nothing has actually changed with the intensity forecast during the day, but it is clear to me that the storm is struggling too much to reintensify as was expected. Statistical guidance does still show strengthening in the marginal conditions over the next few days, but pending some unexpected turn around of the system, I am now calling for the storm to degenerate into a remnant low by day 2 and dissipate later in the forecast period following global model guidance.
Forecast track for Karen has not changed. The storm is still moving northward into a weakness between a ridge and an upper-level low. Eventually, the upper-level low retrogrades to the west-southwest allowing for an expansive ridge to develop to Karen's north forcing the system westward.

FORECAST MAX WINDS
INIT 25/2100Z 35 KT 40 MPH
12H 26/0600Z 30 KT 35 MPH
24H 26/1800Z 30 KT 35 MPH
36H 27/0600Z 25 KT 30 MPH
48H 27/1800Z 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 28/1800Z 20 KT 25 MPH...POST-TROP/REMNT LOW
Atlantic

Archived ATL TWOs

```
Tropical Weather Outlook

0800 AM EDT Jun 18 2022

For the North Atlantic...Caribbean Sea and the Gulf of Mexico:

Tropical cyclone development is not expected in the next five days.

For the eastern North Pacific...east of 140 degrees west longitude:

Tropical cyclone development is not expected in the next five days.

...EXTENDED RANGE DISCUSSION...THROUGH 10 DAYS...

The rising branch of the Madden-Julian oscillation has slowed and coupled itself to the atmospheric expression of the West African Monsoon, leading to an increase in convection over the region. Trade winds in the Atlantic main development region have additionally slowed in response, as flow aloft in the tropics becomes more easterly in nature. Though few models explicitly depict genesis through legitimate means, this paradigm shift -- even if fleeting -- will favor stronger African Easterly Waves crossing the tropical Atlantic. Strong outbreaks of Saharan dust as well as intrusions of midlatitude airmasses should keep development chances low, though a strong wave that manages to sneak past to the south of adverse conditions may be worth watching as we head into the second half of the month.

Ensemble guidance is keying in on a period of atmospheric blocking and weakly -NAO over the North Atlantic beginning early next week and continuing into the longer range period. With an active North American weather pattern comes the potential a system is trapped under this ridging and can undergo tropical or subtropical cyclone genesis. This could be something to watch moving forward as it has been a favored genesis mode early in the season in recent years.

Forecaster Nice

```

### Forecaster Discussions

Since we can afford to wait, I figured we could hold off until further scatterometer and recon confirmation this afternoon on the systems on the Atlantic to get a better handle of the low-level wind structure and the center position before initiating. I have elected not to initiate on the two systems at 15z. —**CobraStrike** (t)(b)(c) 14:27, August 20, 2020 (UTC)

Recon is investigating the system in the Caribbean, finding an ill-defined center and a structure still more resembling a tropical wave axis. This is despite its impressive presentation on satellite. Since the center is likely to jump around in the coming hours, making a forecast now would give one of high uncertainty. The system falls short of TC standards anyway, so I'm holding off. Farther east, the system approaching the Caribbean appears to have acquired a low-level circulation, but convective activity does not meet threshold. I will wait on that one as well. -- TAWX21 20:58, August 20, 2020 (UTC)
Atlantic/2015/02L/Archive/5

## Public advisory

TROPICAL STORM BILL ADVISORY NUMBER 5

WIKI-HURRICANES FORECAST CENTER

1000 AM CDT TUE JUN 16 2015

...BILL SLIGHTLY STRONGER AS IT APPROACHES THE COAST... ...IMPACTS WILL EXTEND FAR INLAND...

SUMMARY OF 1000AM CDT...1500 UTC...INFORMATION

LOCATION... 28.2N 96.4W

ABOUT 15 MI...20 KM S OF PORT O'CONNOR TEXAS

MAXIMUM SUSTAINED WINDS...55 KT...65 MPH...100 KM/H

MINIMUM BAROMETRIC PRESSURE...997 MB...29.44 INCHES

PRESENT MOVEMENT...NW OR 305 DEGREES... AT 9 KT...10 MPH...17 KM/H

DISCUSSION AND 48-HOUR OUTLOOK

At 1000 am CDT, the center of Tropical Storm Bill was located at 28.2N, 96.4W, or about 10 miles (15 km) south of Port O'Connor, Texas. Maximum sustained winds were 55 knots (65 mph, 100 km/h), with higher gusts. The minimum barometric pressure was 997 millibars (hPa; 29.44 inHg), and the system was moving northwest at 9 knots (10 mph, 17 km/h). No change in strength is expected as the center of Bill makes landfall along the southeastern Texas coastline over the next few hours, with steady weakened expected inland.

NEXT ADVISORY

Next complete advisory at 400 pm CDT.

$$

Forecaster TAWX14

## Discussion

TROPICAL STORM BILL DISCUSSION NUMBER 5

WIKI-HURRICANES FORECAST CENTER

1000 AM CDT TUE JUN 16 2015

Bill has strengthened slightly on its approach to the Texas coastline. The Air Force Reverse reconnaissance aircraft investigating the cyclone has observed a slow fall in pressure this morning, down to 997 mb in the latest Vortex Data Message. Flight-level winds have held steady near 60 kt to the northeast of the center, with peak non-contaminated surface winds near 55 kt. Despite satellite intensity estimates of T2.0/30 kt from SAB and TAFB, the initial intensity has been raised to 55 kt in accordance with in-situ observations. The center of Bill is about to make landfall south of Port O'Connor, so no further intensification is expected. Once inland, the system should slowly decay into a remnant low. The forecast is largely unchanged from the previous one.

The track forecast for Bill continues to be straightforward. The storm has taken on more a northwesterly motion this morning as it rounds the southwestern periphery of a potent mid-level ridge across the Southeast United States. This motion is expected for the next 36 to 48 hours. Thereafter, an approaching trough should recurve Bill toward the north and eventually northeast. All models are in good agreement, and the updated track forecast is essentially a blend of global and regional models.

INIT 16/1500Z 28.2N 96.4W 55 KT 65 MPH

12H 17/0000Z 29.6N 97.0W 45 KT 55 MPH...INLAND

24H 17/1200Z 31.5N 97.7W 30 KT 35 MPH...INLAND

36H 18/0000Z 33.4N 97.3W 25 KT 30 MPH...INLAND/REMNT LOW

48H 18/1200Z 35.0N 96.3W 20 KT 25 MPH...INLAND/REMNT LOW

72H 19/1200Z 36.7N 96.2W 15 KT 15 MPH...INLAND/REMNT LOW

96H 20/1200Z...DISSIPATED

$$

Forecaster TAWX14
Atlantic/2019/05L/Archive/34

Although weakening, Dorian remains an extremely powerful category 5 hurricane and the full extent of its fury is still being felt on Grand Bahama right now. Dorian's central dense overcast has been warming over the past few hours as the eyewall replacement cycle gradually results in weakening of the inner eyewall. The eye remains well defined and axisymmetric, although over the past few hours it has experienced some wobbling. Based on slight weakening since the last aircraft reconnaissance data, the initial intensity has been lowered to 145 kt.
Increased mid-level moisture has perhaps allowed the outer banding of Dorian to gather strength and initiate the current eyewall replacement cycle. This will likely continue to decrease the hurricane's intensity in the short-term, but some reintensification afterward cannot be ruled out if the cycle is completed quickly and cleanly. Conditions will remain favorable with warm sea surface temperatures, adequate mid-level moisture, and very good outflow with minimal shear for about the next two days. The main factor that would keep Dorian from remaining a very strong hurricane in this time period would be the onset of upwelling which is becoming more likely as Dorian's forward speed decreases, but the extent to which this will come into play is unclear. Beyond day 2, wind shear will begin to increase with the passage of an upper-level trough and this will begin to weaken the hurricane quicker. This weakening will be intensified by any potential land interaction or ingestion of dry air due to close proximity to land.
Dorian, although with its eye wobbling as a result of inner core dynamics related to the ongoing eyewall replacement cycle, appears to be moving very slowly toward the northwest, which appears to be a signal that the hurricane is beginning its turn toward the north. Current model guidance suggests that Dorian will not complete this turn in its entirety until around 36-48 hours, when it will be heading west-northwest into a weakness in the mid-level ridging, skirting the Floridian coastline. It will then further turn toward the north and northeast around day 4 as it is picked up by an upper-level trough and continues to roughly follow the coast. But here, landfall seems more likely as the storm approaches North Carolina. Beyond this, the storm will move out into the Atlantic Ocean. After the forecast period, effects in Atlantic Canada from a strong extratropical or transitioning cyclone are possible.
FORECAST MAX WINDS
INIT 02/0900Z 145 KT 165 MPH
12H 02/1800Z 140 KT 160 MPH
24H 03/0600Z 130 KT 150 MPH
36H 03/1800Z 125 KT 145 MPH
48H 04/0600Z 115 KT 130 MPH
72H 05/0600Z 105 KT 120 MPH
96H 06/0600Z 90 KT 105 MPH...INLAND