[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 231752
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU APR 23 2009

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N9W 1N20W CROSSING THE EQUATOR NEAR
24W TO 1S40W AND INLAND OVER NE BRAZIL NEAR 2S44W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 5N
BETWEEN 18W-22W. SCATTERED MODERATE CONVECTION IS FROM 1N-3N
BETWEEN 32W-43W.

...DISCUSSION...

GULF OF MEXICO...
A 1025 MB SURFACE HIGH PRESSURE...CURRENTLY CENTERED JUST EAST
OF DAYTONA BEACH FLORIDA NEAR 29N81W...IS SHIFTING E. ACCORDING
TO AN EARLIER QSCAT PASS AROUND 1120 UTC...WINDS ARE LIGHT AND
VARIABLE ACROSS MUCH OF FLORIDA AND THE NE GULF WHILE SLY WINDS
HAVE INCREASED TO 20 KT OVER THE WRN WATERS IN RESPONSE TO LOW
PRESSURE OVER THE S CENTRAL PLAINS. E TO SE WINDS ARE EXPECTED
TO INCREASE TO 20-25 KT OVER MUCH OF THE GULF TONIGHT AND FRI AS
HIGH PRESSURE STRENGTHENS OFF THE SE CONUS COAST IN THE W ATLC.
DRY AIR IN THE MID AND UPPER LEVELS IS SUPPORTING FAIR WEATHER
ACROSS THE ENTIRE REGION. OF NOTE HOWEVER ARE HAZY CONDITIONS
OBSERVED ACROSS THE SW GULF AND BAY OF CAMPECHE AS SMOKE IS
ADVECTING N-NW FROM WILDFIRES ACROSS THE YUCATAN PENINSULA AND
SRN MEXICO. MAINLY FAIR WEATHER IS EXPECTED TO CONTINUE OVER THE
NEXT COUPLE OF DAYS...THOUGH ISOLATED SHOWERS WILL LIKELY
DEVELOP IN THE STRONG LOW-LEVEL FLOW.

CARIBBEAN SEA...
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS LOCATED OVER
THE EXTREME SW CARIBBEAN S OF 12N W OF 81W. LOW-LEVEL LIFT FROM
SURFACE WIND CONVERGENCE OF THE ELY TRADES AND UPPER DIFFLUENCE
APPEAR TO BE THE PRIMARY FACTORS FUELING THE CONVECTION. SWLY
FLOW ALOFT IS SPREADING MOISTURE NE THOUGH IT APPEARS TO REMAIN
IN THE FORM OF MID-HIGH LEVEL CLOUDINESS. MORE DENSE CLOUDINESS
AND POSSIBLE ISOLATED SHOWERS ARE OBSERVED OVER HISPANIOLA AND
ADJACENT COASTAL WATERS ASSOCIATED WITH A WEAK STATIONARY FRONT
LOCATED NORTH OF THE ISLAND IN THE W ATLC AND LIKELY ENHANCED BY
UPSLOPE FLOW. TRADE WINDS ARE IN THE 20-25 KT RANGE OVER THE WRN
CARIBBEAN...EXCEPT FOR 25-30 KT NEAR THE COAST OF COLOMBIA...AND
MAINLY 15-20 KT ELSEWHERE. THESE WINDS ARE EXPECTED TO PERSIST
THROUGH THE WEEKEND AS HIGH PRESSURE STRENGTHENS OVER THE W ATLC
GRADUALLY REINFORCING THE PRESSURE GRADIENT ALREADY IN PLACE
OVER THE REGION.

ATLANTIC OCEAN...
SCATTERED SHOWERS AND TSTMS ARE WITHIN 200 NM E OF A COLD FRONT
EXTENDING FROM 32N64W TO 24N69W THEN STATIONARY TO NORTHWEST
HISPANIOLA. THIS ACTIVITY IS BEING ENHANCED BY STRONG SWLY UPPER
FLOW AND A DIFFLUENT PATTERN BETWEEN THE ASSOCIATED TROUGH ALONG
THE ERN CONUS SEABOARD AND AN AMPLIFIED RIDGE OVER THE CENTRAL
ATLC. FARTHER TO THE W...A 1025 MB SURFACE HIGH PRESSURE
CENTERED JUST E OF DAYTONA BEACH FLORIDA IS DRIFTING E...
BRINGING FAIR WEATHER CONDITIONS TO THE W ATLC IN THE WAKE OF
THE FRONT. OVER THE E CENTRAL ATLC...DEEP LAYER TROUGHING
REMAINS WELL DEFINED ON WATER VAPOR IMAGERY PROVIDING SOME
SUPPORT FOR POSSIBLE SCATTERED SHOWERS COVERING THE AREA FROM
23N-30N BETWEEN 33W-39W. THE TIGHT PRESSURE GRADIENT INDUCED
OVER THIS AREA IS CAUSING STRONG NE 20-30 KT FLOW WITH HIGHER
GUSTS. AN UPPER JET EXTENDING NE FROM 13N37W TO N OF THE CAPE
VERDE ISLANDS IS ADVECTING SOME MOISTURE WITHIN 300 NM E OF THE
JET AXIS.

$$
HUFFMAN


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