[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 201049
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED 20 APR 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 0600 UTC SURFACE ANALYSIS AND
SATELLITE IMAGERY THROUGH 0945 UTC.

...THE ITCZ...

ITCZ 9N5W 7N10W 3N20W 1N30W 2N40W 5N50W 5N60W. STRONG SHOWERS
AND THUNDERSTORMS FROM 1N TO 2N BETWEEN 22W AND 25W. WARMING
CLOUD TOP TEMPERATURES BUT LINGERING SHOWERS AND THUNDERSTORMS
FROM 2N TO 6N BETWEEN 20W AND 27W. WIDELY SCATTERED MODERATE
TO ISOLATED STRONG SHOWERS AND THUNDERSTORMS FROM THE EQUATOR
TO 7N BETWEEN 40W AND 50W. SCATTERED MODERATE TO ISOLATED
STRONG SHOWERS AND THUNDERSTORMS WITHIN 15 TO 20 NM ON EITHER
SIDE OF 3N7W 3N13W...DECREASING IN COVERAGE AND INTENSITY
WITHIN 15 TO 20 NM ON EITHER SIDE OF 3N7W TO 5N1W.

...DISCUSSION...

THE GULF OF MEXICO...
THE SMALL SCALE CYCLONIC CIRCULATION CENTER IN WEST TEXAS SIX
HOURS AGO HAS MOVED TO 31N101W...AND WEAKENED. BROAD MIDDLE TO
UPPER LEVEL ANTICYCLONIC FLOW WITH A RIDGE COVERS THE AREA FROM
THE EASTERN PACIFIC OCEAN TO INTERIOR MEXICO TO THE GULF OF
MEXICO. THE RIDGE IS ALONG 99W. SURFACE RIDGE THROUGH 34N58W TO
1025 MB HIGH PRESSURE CENTER NEAR 31N72W TO 31N80W TO 1021 MB
HIGH PRESSURE CENTER NEAR 32N86W IN SOUTHEASTERN ALABAMA. A
BROAD RIDGE ALSO CONTINUES TO THE SOUTHWESTERN CORNER OF THE
AREA NEAR 21N98W. THERE IS NO INDICATION OF A FRONT MOVING INTO
THE AREA THROUGH THURSDAY. GFS CURRENTLY INDICATING A BACK-DOOR
TYPE FRONT MAY REACH NORTH FLORIDA LATE THURSDAY INTO
FRIDAY...POSSIBLY INTRODUCING SHOWERS OR THUNDERSTORMS TO THAT
AREA. A SHORTWAVE TROUGH GOES FROM SOUTHEASTERN LOUISIANA TO
27N86W IN THE GULF WATERS. MIDDLE TO UPPER LEVEL DRY AIR ALSO IS
PUSHING SOUTHEASTWARD FROM LOUISIANA TO THE SOUTHWESTERN COAST
OF FLORIDA. THIS SHORTWAVE WILL CONTINUE TO DROP SOUTHEASTWARD
ACROSS FLORIDA TODAY WITH POSSIBLE SHOWERS AND THUNDERSTORMS.
MAINLY DRY AND TRANQUIL CONDITIONS WILL PREVAIL ELSEWHERE
ESPECIALLY TOWARD THE END OF THE WEEK AS AN UPPER LEVEL LONGWAVE
TROUGH SETS UP JUST EAST OF FLORIDA. THIS WOULD PUT MUCH OF THE
EASTERN GULF AND FLORIDA WITHIN THE DRY AND CONFLUENT SIDE OF
THE TROUGH ESPECIALLY AS STRONG MIDDLE TO UPPER LEVEL RIDGING
DEVELOPS OVER MEXICO ON FRIDAY. SUBTROPICAL SURFACE RIDGE WILL
MOVE LITTLE DURING THE NEXT SEVERAL DAYS KEEPING MUCH OF THE
AREA UNDER LIGHT TO MODERATE EAST TO SOUTHEAST WIND FLOW.

THE CARIBBEAN SEA...
PURELY UPPER LEVEL SOUTHWESTERLY WIND FLOW MOVES ACROSS
THE AREA...FROM THE SOUTHWESTERN CORNER TO AND BEYOND THE
NORTHEASTERN CORNER. THIS SOUTHWESTERLY WIND FLOW COMES FROM
AN UPPER LEVEL RIDGE OVER SOUTH AMERICA...AND COMBINES WITH
MIDDLE TO UPPER LEVEL WESTERLY TO NORTHWESTERLY FLOW IN A
TROUGH WHICH RUNS FROM HONDURAS TO 120 NM SOUTH OF
JAMAICA...ACROSS HISPANIOLA...BEYOND 30N62W.

THE ATLANTIC OCEAN...
CLOSED OFF MIDDLE LEVEL CYCLONIC CIRCULATION CENTER NEAR 30N64W.
LARGE SCALE TROUGH FROM THIS CYCLONIC CENTER TO A POINT ABOUT
120 NM EAST OF THE SOUTHERN BAHAMAS. THIS TROUGH STILL SUPPORTS
THE PERSISTENT FRONTAL BOUNDARY...COLD FRONT THROUGH 32N41W TO
27N50W TO 23N57W. STATIONARY FRONT CONTINUES FROM 23N57W TO
20N64W...THROUGH THE MONA PASSAGE TO 17N74W. EASTERN ATLANTIC
OCEAN SURFACE RIDGE FROM 1024 MB MADEIRA ISLANDS HIGH PRESSURE
CENTER TO 27N38W AND 21N49W. MIDDLE TO UPPER LEVEL TROUGH GOES
FROM A CYCLONIC CIRCULATION CENTER NEAR 21N31W TO 14N31W TO
3N36W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE
PRECIPITATION ARE CURVING NORTHWARD...FROM 7N TO 24N BETWEEN
20W AND 29W...ON THE EASTERN SIDE OF THIS TROUGH.

$$
MT




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