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Subtropical Storm FAY Forecast Discussion Number 3
2014-10-11 01:38:12| National Hurricane Center (Atlantic)
Issued at 730 PM AST FRI OCT 10 2014 000 WTNT42 KNHC 102338 TCDAT2 SUBTROPICAL STORM FAY SPECIAL DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072014 730 PM AST FRI OCT 10 2014 As the Air Force Reserve Hurricane Hunter aircraft exited through an area of very deep convection in the northwestern quadrant of Fay, they found a peak 5,000 ft flight-level wind of 75 kt and peak SFMR winds in the 50-55 kt range. Based on these data, this special advisory is being issued to increase the initial intensity to 50 kt, which could be a bit conservative. The aircraft also found that the central pressure had fallen to 1000 mb on their last pass through the broad center. The intensity forecast has been adjusted upward through 36 hours, and shows the possibility for some additional strengthening before gradual weakening begins after 24 hours. Aircraft fixes and satellite imagery suggest that the initial motion is 340/10, a bit to the right of the previous track. Based on this, the 12-hour forecast position has been nudged a little to the east, but no changes were made to the NHC track at 24 hours and beyond. Note that this special advisory takes the place of the scheduled 800 PM AST...0000 UTC...intermediate advisory. The next advisory issued on Fay will be the full advisory package at 1100 PM AST...0300 UTC. FORECAST POSITIONS AND MAX WINDS INIT 10/2330Z 25.2N 64.2W 50 KT 60 MPH 12H 11/0600Z 26.0N 64.8W 55 KT 65 MPH 24H 11/1800Z 28.5N 65.2W 55 KT 65 MPH 36H 12/0600Z 31.7N 63.7W 50 KT 60 MPH 48H 12/1800Z 33.7N 60.4W 45 KT 50 MPH 72H 13/1800Z...ABSORBED BY FRONTAL SYSTEM $$ Forecaster Brennan
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Subtropical Storm FAY Forecast Discussion Number 2
2014-10-10 22:58:41| National Hurricane Center (Atlantic)
Issued at 500 PM AST FRI OCT 10 2014 000 WTNT42 KNHC 102058 TCDAT2 SUBTROPICAL STORM FAY DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072014 500 PM AST FRI OCT 10 2014 Satellite imagery and data from an Air Force Reserve reconnaissance aircraft indicate that the subtropical cyclone has become a little better organized since the previous advisory. Deep convection has gradually been developing closer to the low-level circulation center, and a maximum SFMR surface wind measured thus far by the aircraft has been 35 kt. Based on this information, plus a subtropical satellite classification of ST2.5/35 kt from TAFB, this system has been upgraded to Subtropical Storm Fay. The Hurricane Hunter aircraft will continue investigating Fay for the next hour or so. The initial motion estimate is 330/10 kt. Fay is expected to move steadily northwestward and then northward around the western periphery of a deep-layer subtropical ridge located along 29N-30N latitude for the next 24 hours. By 36 hours, the cyclone is expected to recurve toward the northeast and accelerate when it becomes embedded in the strong mid-latitude flow ahead of an approaching shortwave trough that is currently located near the U.S. east coast. The latest NHC model guidance has shifted somewhat to the west, especially the ECMWF model, but the models remain tightly clustered and in good agreement on the aforementioned track scenario, including absorption by a frontal system by 72 hours. The official track has been shifted to the left of the previous forecast and lies just to the west of and a little slower than the consensus track model TVCN. The large size of Fay, along with strong southeasterly to southerly vertical wind shear, should inhibit much in the way of intensification, despite the cyclone being over anomalously warm 29C sea-surface temperatures. If the recent trend in the development of inner-core convection continues, then Fay could transition into a tropical cyclone within the next 12 hours or so. However, this transition would have virtually no effect on the size of the tropical-storm-force wind field. The NHC intensity forecast closely follows a blend of the statistical-dynamical models SHIPS and LGEM. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 24.7N 64.2W 35 KT 40 MPH 12H 11/0600Z 26.0N 65.0W 40 KT 45 MPH 24H 11/1800Z 28.5N 65.2W 45 KT 50 MPH 36H 12/0600Z 31.7N 63.7W 45 KT 50 MPH 48H 12/1800Z 33.7N 60.4W 45 KT 50 MPH 72H 13/1800Z...ABSORBED BY FRONTAL SYSTEM $$ Forecaster Stewart
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Subtropical Depression SEVEN Forecast Discussion Number 1
2014-10-10 16:47:11| National Hurricane Center (Atlantic)
Issued at 1100 AM AST FRI OCT 10 2014 000 WTNT42 KNHC 101447 TCDAT2 SUBTROPICAL DEPRESSION SEVEN DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072014 1100 AM AST FRI OCT 10 2014 Satellite images indicate that the area of low pressure located several hundred miles north of the northern Leeward Islands has developed a large area of deep convection in a long curved band north and west of the center. First-light visible satellite imagery also indicates that the low-level center of the low has become better defined since yesterday. Satellite classifications are a subtropical 1.5 from TAFB and SAB at 1200 UTC, and the system's involvement with a nearby upper-level low and roughly 100 n mi radius of maximum winds also argue for a subtropical designation. An Air Force Hurricane Hunter aircraft will investigate the depression this afternoon to better assess its intensity and structure. The protective cover of the nearby upper low will provide a relatively low vertical wind shear environment in the short term, with the cyclone over warm sea surface temperatures of 28- 29 deg C. The model guidance indicates that the depression should become embedded in increasing southerly vertical shear east of the same upper-level trough after 24 hours, so the system has a short window for intensification or transformation into a tropical cyclone. Global models depict the cyclone becoming absorbed by a frontal zone over the north-central Atlantic before 72 hours. The NHC intensity forecast is close to the statistical-dynamical guidance. The depression is moving northwestward or 320/09 around the southwestern perhiphery of a mid-level ridge over the central Atlantic. The deep-layer steering flow around this feature should cause the cyclone to turn northward within 24 hours, after which it will turn northeastward in increasing southwesterly flow at the base of a longwave trough prior to absorption by the front. The NHC track forecast is very close to the multi-model consensus, TVCA, through- out the period and between the ECMWF and GFS model solutions. The Bermuda Weather Service has issued a tropical storm watch for Bermuda. FORECAST POSITIONS AND MAX WINDS INIT 10/1500Z 23.8N 63.7W 30 KT 35 MPH 12H 11/0000Z 25.1N 64.6W 35 KT 40 MPH 24H 11/1200Z 26.8N 65.1W 40 KT 45 MPH 36H 12/0000Z 29.4N 64.7W 40 KT 45 MPH 48H 12/1200Z 31.5N 62.9W 40 KT 45 MPH 72H 13/1200Z...DISSIPATED $$ Forecaster Kimberlain
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Post-Tropical Cyclone SIMON Forecast Discussion Number 26
2014-10-08 04:42:27| National Hurricane Center (East Pacific)
Issued at 800 PM PDT TUE OCT 07 2014 000 WTPZ44 KNHC 080242 TCDEP4 POST-TROPICAL CYCLONE SIMON DISCUSSION NUMBER 26 NWS NATIONAL HURRICANE CENTER MIAMI FL EP192014 800 PM PDT TUE OCT 07 2014 Simon has been devoid of organized deep convection for more than 12 hours. Strong shear and an unfavorable thermodynamic environment should prevent any significant redevelopment of convection, and the system is being declared a post-tropical remnant low at this time. Based on earlier ASCAT data, the initial wind speed remains 30 kt for this advisory. The low should weaken during the next day or so, and the global models suggest that the cyclone will become an open trough within 24 to 48 hours as it interacts with land. The low has turned northeastward this evening with an initial motion estimate of 040/6 kt. A northeastward motion with some increase in forward speed is expected until dissipation occurs. This will take the cyclone, or its remnant, across north-central Baja California and into Mainland Mexico. Even if Simon or its remnant surface circulation does not make it across the rugged terrain of the Baja California peninsula, moisture associated with this system is expected to spread across the northern Baja California peninsula, northwestern Mexico, and into the U.S. Desert Southwest, which could trigger heavy rains in those regions during the next couple of days. Please refer to statements from your local weather office for information on hazards specific to your area. This is the last advisory issued by the National Hurricane Center on Simon. For additional information on the remnant low please see High Seas Forecasts issued by the National Weather Service...under AWIPS header NFDHSFEPI and WMO header FZPN01 KWBC. FORECAST POSITIONS AND MAX WINDS INIT 08/0300Z 28.1N 115.8W 30 KT 35 MPH...POST-TROP/REMNT LOW 12H 08/1200Z 28.9N 114.8W 25 KT 30 MPH...POST-TROP/REMNT LOW 24H 09/0000Z 30.5N 113.5W 20 KT 25 MPH...POST-TROP/REMNT LOW 36H 09/1200Z...DISSIPATED $$ Forecaster Brown
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Tropical Depression SIMON Forecast Discussion Number 25
2014-10-07 22:36:23| National Hurricane Center (East Pacific)
Issued at 200 PM PDT TUE OCT 07 2014 000 WTPZ44 KNHC 072036 TCDEP4 TROPICAL DEPRESSION SIMON DISCUSSION NUMBER 25 NWS NATIONAL HURRICANE CENTER MIAMI FL EP192014 200 PM PDT TUE OCT 07 2014 An ASCAT pass from a few hours ago indicates that there are no longer winds of tropical storm force in the circulation. Therefore the system is being downgraded to a depression and the tropical storm watch for Baja California is discontinued. The current intensity is 30 kt, and since the wind shear over Simon is forecast to be very strong and even increase a little more over the next day or so, additional weakening is expected. The interaction with land could cause even more weakening than indicated here. In any event, given the lack of deep convection, the system is likely to degenerate into a remnant low tonight. The north-northeastward motion continues, at around 030/6. A consensus of the dynamical guidance calls for this general direction of motion with a little acceleration, for the next 24-36 hours. This will take Simon, or its remnant low, across north-central Baja California and into Mainland Mexico. Even if Simon or its remnant surface circulation does not make it across the rugged terrain of the Baja California peninsula, moisture associated with this system is expected to spread across the northern Baja California peninsula, northwestern Mexico, and into the U.S. Desert Southwest, which could trigger heavy rains in those regions during the next few days. Please refer to statements from your local weather office for information on hazards specific to your area. FORECAST POSITIONS AND MAX WINDS INIT 07/2100Z 27.9N 116.3W 30 KT 35 MPH 12H 08/0600Z 28.8N 115.6W 30 KT 35 MPH...POST-TROP/REMNT LOW 24H 08/1800Z 30.5N 114.4W 25 KT 30 MPH...POST-TROP/REMNT LOW 36H 09/0600Z 32.2N 113.2W 20 KT 25 MPH...POST-TROP/REMNT LOW 48H 09/1800Z...DISSIPATED $$ Forecaster Pasch
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