簽到天數: 1650 天 [LV.Master]伴壇終老
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老農民版夜神月|2021-8-16 11:09
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已重新增強至45KT,預計將以50KT強度登陸美國
285
WTNT41 KNHC 160244
TCDAT1
Tropical Storm Fred Discussion Number 26
NWS National Hurricane Center Miami FL AL062021
1000 PM CDT Sun Aug 15 2021
Fred remains a sheared tropical cyclone however the overall
organization of the system has improved somewhat since this
afternoon. The low-level center is embedded near the western edge
of the primary convective mass, and there has been an overall
increase in deep convection near and to the east of the center. An
Air Force Reserve reconnaissance aircraft that has been
investigating Fred this evening has reported that the pressure has
fallen to 999 mb and it has found winds to support an initial
intensity of 45 kt. The plane found a very small area of slightly
stronger flight-level and SFMR winds well east of the center, but
those winds appear to have been associated with a strong convective
cell and are likely not representative of the system's overall
intensity.
Fred is moving north-northwestward or 330/08 kt, and this motion
should continue overnight. The dynamical model guidance indicates
that the tropical cyclone will turn northward on Monday as it
approaches the coast of the Florida panhandle. A north-
northeastward motion around the western periphery of a subtropical
ridge over the western Atlantic should commence by the time the
system makes landfall, and this general heading should continue
until the system dissipates in a couple of days. The dynamical
models envelope did not change much and the latest consensus aids
were essentially along the previous NHC track. As a result, little
alteration was made to the previous official track forecast.
The cyclone is located within an area of moderate southwesterly
vertical wind shear. However, most of the intensity guidance
continues to suggest that Fred will strengthen a little over the
next 12-18 hours. As the system nears the northern Gulf coast, the
SHIPS guidance forecasts some increase in shear and the intensity
models reflect this by showing a leveling off of Fred's intensity at
that time. After landfall, Fred should weaken quickly and dissipate
over the Tennessee Valley in a little more than 48 hours. The
updated NHC intensity forecast is in good agreement within the HCCA
and IVCN consensus aids.
Users are reminded not to focus on the exact forecast track of
Fred, since rainfall, storm surge, and wind hazards will extend
over an area well east of the center.
KEY MESSAGES:
1. Through Tuesday, heavy rainfall may lead to flash, urban, small
stream, and isolated river flooding impacts across the Southeast,
including portions of southern Florida, the Big Bend and Panhandle
of Florida, southeast Alabama, portions of Georgia, and the western
Carolinas. By the middle of the week as Fred lifts north and inland
toward the Tennessee Valley, heavy rainfall and flooding may impact
the southern and central Appalachians, and the Piedmont of the
Southeast and Mid-Atlantic.
2. Dangerous storm surge inundation is possible along portions of
the coast of the Florida Panhandle and the Florida Big Bend region,
and a Storm Surge Warning is in effect for this area. Interests in
these areas should follow any advice given by local officials.
3. Tropical storm conditions are expected in the Tropical Storm
Warning area in the Florida Panhandle beginning on Monday.
FORECAST POSITIONS AND MAX WINDS
INIT 16/0300Z 27.3N 85.9W 45 KT 50 MPH
12H 16/1200Z 28.6N 86.2W 50 KT 60 MPH
24H 17/0000Z 30.2N 86.1W 50 KT 60 MPH
36H 17/1200Z 32.3N 85.7W 30 KT 35 MPH...INLAND
48H 18/0000Z 34.4N 84.9W 20 KT 25 MPH...POST-TROP/INLAND
60H 18/1200Z...DISSIPATED
$$
Forecaster Brown
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