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Potential Tropical Cyclone One Forecast Discussion


000
WTNT41 KNHC 042033
TCDAT1

Potential Tropical Cyclone One Discussion Number   9
NWS National Hurricane Center Miami FL       AL012022
500 PM EDT Sat Jun 04 2022

Radar data and surface observations indicate that the circulation 
of the disturbance has become a little better defined since the 
last advisory, although the central area still consists of an area 
of multiple vorticity maxima extending from near Lake Okeechobee 
east-northeastward into the Atlantic.  While the current structure 
still does not justify an upgrade to a tropical storm, the 
easternmost of these centers is near the main convective area, and 
if this continues the system could become a tropical storm in the 
next 6-12 hours.  An earlier Air Force Reserve Hurricane Hunter 
mission reported a large area of 50-kt winds at 3000 ft, and 
believable SFMR surface wind estimates of 35-40 kt.  Based on these 
data, the initial intensity is increased to 40 kt.

The initial motion is 050/16, and some of this is due to the
ongoing re-formations of the center.  The track guidance remains in 
good agreement that a general northeastward motion should continue
through Sunday, followed by an east-northeastward to eastward
motion Monday and Tuesday.  On the forecast track, the system will
move away from Florida tonight, and then pass north of Bermuda on 
Monday on its way into the central Atlantic.

Water vapor and air mass imagery show a mid- to upper-level trough
over the southeastern United States and the eastern Gulf of Mexico.
While this trough continues to aid strong westerly shear over the
disturbance, the interaction between this trough and the
disturbance is forecast to lead to a better-defined circulation
during the next 12-24 h, which should allow the disturbance to
become a tropical storm and strengthen a little.  The long-term 
forecast for the system has gotten murkier.  After about 60-72 h, 
several of the global models essentially split the system in two, 
with a center that forms in the northern part of the circulation 
merging with a frontal system to become an extratropical low, while 
the rest of the system turns more southward and slows down well to 
the east of Bermuda.  Given the uncertainty, there will be no 
changes at this time from the previous forecast of extratropical 
transition and the associated track forecast.  However, there is 
now an alternate scenario that may require changes to the track and 
intensity forecasts in later advisories.

KEY MESSAGES:

1. Heavy rainfall will diminish across South Florida and the Keys 
through this evening. Heavy rain will continue across the 
northwestern Bahamas tonight before diminishing by early Sunday. 
Heavy rain may begin to impact Bermuda Sunday night into Monday. The 
threat of flash flooding will continue to diminish this evening 
across South Florida, but urban flooding will continue. Flash and 
urban flooding is possible across the northwestern Bahamas.

2. Tropical storm conditions are expected in the warning area in
in the northwestern Bahamas for the next several hours, and are 
possible on Bermuda on Monday..


FORECAST POSITIONS AND MAX WINDS

INIT  04/2100Z 27.8N  79.8W   40 KT  45 MPH...POTENTIAL TROP CYCLONE
 12H  05/0600Z 29.2N  77.6W   45 KT  50 MPH...TROPICAL CYCLONE
 24H  05/1800Z 31.1N  74.0W   45 KT  50 MPH
 36H  06/0600Z 32.8N  69.8W   45 KT  50 MPH
 48H  06/1800Z 34.4N  64.9W   45 KT  50 MPH
 60H  07/0600Z 35.3N  59.6W   45 KT  50 MPH
 72H  07/1800Z 36.9N  54.3W   40 KT  45 MPH...POST-TROP/EXTRATROP
 96H  08/1800Z 40.0N  44.5W   40 KT  45 MPH...POST-TROP/EXTRATROP
120H  09/1800Z 44.5N  35.0W   30 KT  35 MPH...POST-TROP/EXTRATROP

$$
Forecaster Beven



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