[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 052245
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT THU 05 MAY 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA... GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN
SECTIONS OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN
COAST FROM THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...
AND METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2215 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 61W DRIFTING WESTWARD. THE WAVE IS EMBEDDED
WITHIN MODERATE NW FLOW ALOFT WHICH IS DISPLACING MOST OF THE
SHOWER/THUNDERSTORM ACTIVITY TO THE E OF THE LESSER ANTILLES AND
APPEARS TO BE ELONGATING AS IT PASSES OVER THE ISLANDS.
CURRENTLY...SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE FROM
11N-14N BETWEEN 56W-60.5W INCLUDING BARBADOS. THIS ACTIVITY WILL
BE SPREADING ACROSS THE LEEWARD/WINDWARD ISLANDS OVER THE NEXT 6
TO 12 HOURS BRINGING LOCALLY HEAVY RAINFALL AND GUSTY WINDS TO
THE ISLANDS,

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 9N10W 7N18W 3N33W 3N45W 2N52W.
SCATTERED THUNDERSTORMS ARE WITHIN 120 NM EITHER SIDE OF AXIS
FROM 35W-42W AND WITHIN 90 NM S OF THE AXIS FROM 23W-26W.

...DISCUSSION...

GULF OF MEXICO...
ANOTHER ACTIVE DAY FOR CONVECTION OVER THE E GULF AND THE
FLORIDA PENINSULA TODAY AS A POTENT MID/UPPER LEVEL SHORTWAVE
TROUGH FROM N ALABAMA S TO THE FLORIDA KEYS INTERACTS WITH THE
PRE-EXISTING FRONTAL BOUNDARY WHICH HAS PERSISTED ACROSS FLORIDA
AND THE SE GULF DURING THE LAST FEW DAYS. THE BOUNDARY CURRENTLY
EXTENDS ACROSS CENTRAL FLORIDA NEAR ORLANDO WESTWARD TO A 1015
MB LOW NEAR 28N85W. COLD FRONT TRAILS SW FROM THE LOW TO 22N89W
WHERE IT BECOMES STATIONARY INTO THE BAY OF CAMPECHE NEAR THE
ISTHMUS OF TEHUANTEPEC. SATELLITE IMAGERY INDICATES THE LOW HAS
BECOME BETTER ORGANIZED OVER THE PAST FEW HOURS AND WILL BEGIN
TO MOVE NE OVERNIGHT AND SHOULD MOVE ACROSS N FLORIDA BY
MORNING. AS IT DOES...IT WILL DRAG THE PREVIOUSLY STATIONARY
FRONT OVER THE E GULF WITH WIDESPREAD SHOWERS/THUNDERSTORMS
CLEARING FLORIDA BY FRIDAY NIGHT. LATEST SATELLITE AND RADAR
IMAGERY SHOWS AN AREA OF ACTIVE CONVECTION OVER THE SE GULF S OF
THE LOW MOVING TOWARD THE FLORIDA KEYS. SCATTERED SHOWERS WITH
ISOLATED THUNDERSTORMS ARE MOVING E ACROSS THE FLORIDA PENINSULA
FROM W CUBA TO JUST E OF LAKE OKEECHOBEE. WITH THE FRONTAL
PASSAGE...EXPECT DRYING THROUGH ALL LEVELS OF THE ATMOSPHERE
WHICH WILL PRODUCE RAPID CLEARING FROM WEST TO EAST FINALLY
BRINGING AN END TO THE UNSETTLED/WET PATTERN OVER THE E GULF AND
FLORIDA DURING THE LAST SEVERAL DAYS.

CARIBBEAN SEA...
BROAD MID/UPPER LEVEL RIDGE COVERS THE CARIBBEAN SEA WITH MEAN
AXIS EXTENDING FROM AN UPPER HIGH ALONG THE NW COAST OF COLOMBIA
NE ACROSS HISPANIOLA INTO THE CENTRAL ATLC. THE MID/UPPER LEVELS
REMAIN RELATIVELY DRY WITH MODERATE SUBSIDENCE COVERING ALL BUT
THE EXTREME W PORTION OF THE AREA WHERE THE UPSTREAM TROUGH IS
PRODUCING SOME MOISTURE ADVECTION FROM THE SW. AT THE SURFACE...
COLD FRONT OVER THE E GULF IS PRODUCING AN AREA OF CLOUDINESS
WITH SCATTERED SHOWERS/THUNDERSTORMS MOVING FROM THE SE GULF
INTO THE YUCATAN CHANNEL AND W CUBA N OF 20N W OF 82W. THIS
ACTIVITY HAS BEEN ADVANCING SE TODAY AND THE FRONT IS EXPECTED
TO MOVE SE DURING THE NEXT 24 HOURS ENTERING THE EXTREME NW
CARIBBEAN FRIDAY. THE BULK OF THE UPPER LEVEL DYNAMICS ARE
EXPECTED TO BE N OF THE AREA. HOWEVER...SCATTERED SHOWERS/
THUNDERSTORMS ARE POSSIBLE ALONG AND AHEAD OF THE FRONT
ESPECIALLY OVER THE YUCATAN PENINSULA WHERE SEA BREEZE ACTIVITY
MAY CONTRIBUTE. FRONT WILL LIKELY BECOME DIFFUSE FRI NIGHT INTO
SAT WITH ASSOCIATED SHOWER/THUNDERSTORM ACTIVITY MAINLY OVER
CENTRAL AND E CUBA. ELSEWHERE...TROPICAL WAVE CURRENTLY ENTERING
THE AREA OVER THE LEEWARD/WINDWARD ISLANDS WITH ASSOCIATED AREA
OF SCATTERED SHOWERS/THUNDERSTORMS TO THE EAST. EXPECT HIGHER
THAN USUAL SHOWERS/THUNDERSTORMS OVER THE E CARIBBEAN DURING THE
NEXT DAY OR TWO AS THIS FEATURE MOVES THROUGH THE AREA.

ATLANTIC OCEAN...
AMPLIFYING MID/UPPER LEVEL TROUGH AND ASSOCIATED SURFACE LOW
OVER THE E GULF OF MEXICO AND THE 1015 MB LOW OFF THE NE COAST
OF FLORIDA NEAR 30N79W WILL BE THE BIG WEATHER MAKER DURING THE
NEXT 48 HOURS. THE GULF LOW WILL TRACK ACROSS N FLORIDA TONIGHT
THEN MOVE ALONG THE SE COAST OF THE UNITED STATES ON FRIDAY WITH
THE W ATLC LOW MOVING NE OUT OF THE AREA LATER TONIGHT. THIS
WILL SWEEP A LATE SEASON COLD FRONT ACROSS FLORIDA TONIGHT INTO
FRIDAY WITH SCATTERED TO LOCALLY NUMEROUS SHOWERS/THUNDERSTORMS
IN ADVANCE. IN FACT...ASSOCIATED SHOWERS/THUNDERSTORMS ARE
ALREADY OVER THE NE BAHAMA ISLANDS AND ARE SPREADING E ACROSS
CUBA. THIS ACTIVITY WILL CONTINUE TO EXPAND EASTWARD ACROSS THE
W ATLC TONIGHT WITH LOCALLY HEAVY RAINFALL AND GUSTY WINDS
POSSIBLE MAINLY OVER THE BAHAMAS. THE CORE OF THE STRONGEST
UPPER DYNAMICS LIFT N OF THE AREA DURING THE DAY ON FRIDAY.
HOWEVER...GOOD LOW LEVEL MOISTURE POOLING AND DIFFLUENT FLOW
ALOFT WILL CONTINUE TO SUPPORT SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ALONG THE FRONT AS IT PUSHES THROUGH THE BAHAMAS
FRIDAY AFTERNOON. ELSEWHERE ACROSS THE CENTRAL AND WESTERN
ATLC...STRONG MID/UPPER LEVEL RIDGING IN ADVANCE OF THIS
SYSTEM...FROM HISPANIOLA TO BEYOND 32N55W...IS PRODUCING DRY AND
TRANQUIL CONDITIONS. OVER THE E ATLC...THE DEEP LAYERED LOW NEAR
31N30W WITH THE UPPER LOW NEAR 33N34W CONTINUES TO LIFT SLOWLY
NWD. MOST OF THE SIGNIFICANT CLOUDINESS AND SHOWERS/
THUNDERSTORMS WITH THIS SYSTEM IS NOW N OF 32N. ONLY LOW LEVEL
CLOUDS WITH A FEW ISOLATED SHOWERS ACCOMPANY THE TRAILING
WEAKENING COLD FRONT ALONG 31N25W TO 21N28W THEN DISSIPATING
NEAR 15N37W. A SURFACE TROUGH EXTENDS W OF THE FRONT FROM 31N27W
SW TO 22N33W. EXPECT THE LOW TO BE N OF THE AREA BY FRI
AFTERNOON AS THE ASSOCIATED HIGH WINDS HAVE ALREADY DIMINISHED.
OVER THE TROPICAL ATLC...AREAS OF DUST NOTED S OF A LINE FROM
THE CANARY ISLANDS W OF THE CAPE VERDE ISLANDS ALONG THE ABOVE
FRONTAL BOUNDARY TO THE ITCZ.

$$
WALLACE


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