[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 141755
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 14 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.

...TROPICAL WAVES...
THE TROPICAL WAVE THAT WAS PREVIOUSLY ANALYZED ALONG 20W IS NO
LONGER ON THE SURFACE AND IS NOT ON THE 1200 UTC MAP.
PRECIPITABLE WATER DOES INDICATE AN ABUNDANCE OF MOISTURE BUT
THERE IS NO EVIDENCE OF ROTATION OR CURVATURE IN THE FIELDS AT
THE LOW OR UPPER LEVELS.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 3N17W ALONG THE EQUATOR
BETWEEN 32W-44W TO JUST S OF THE EQUATOR AND INLAND OVER NE
BRAZIL NEAR 0.5S50W. SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS WITHIN 125 NM ON EITHER SIDE OF THE ITCZ BETWEEN
42W-50W. THE REMAINDER OF THE ITCZ IS RATHER QUIET WITH CLEAR
SKIES N OF 4N W OF 20W TO INLAND OVER W AFRICA.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE ANCHORED IN THE E PACIFIC REGION COVERS THE GULF
WITH A LITTLE TROPICAL MOISTURE BEING ADVECTED AND ONLY HIGH
THIN CLOUDS OVER THE NE GULF REMAINING. ELSEWHERE...FAIR WEATHER
DOMINATES THE AREA WITH SHIP AND BUOY OBSERVATIONS INDICATING
MODERATE/STRONG SE TO S WINDS OVER THE W GULF AND E TO SE WINDS
OVER THE E GULF IN RESPONSE TO THE RETURN FLOW TO A SURFACE
RIDGE EXTENDING FROM THE W ATLC TO OVER THE SE US. THIS PATTERN
IS EXPECTED TO REMAIN FOR THE NEXT FEW DAYS UNTIL THE NEXT FRONT
ENTERS THE NW GULF ON LATE SAT/EARLY SUN.

CARIBBEAN SEA...
THE CARIBBEAN IS DOMINATED BY AN UPPER TROUGH THAT EXTENDS FROM
THE W/CENTRAL ATLC THROUGH AN UPPER LOW JUST N OF THE WINDWARD
PASSAGE SW TO THE PANAMA/COSTA RICA BORDER COVERING THE AREA W
OF 67W. THIS UPPER TROUGH IS SUPPORTING A SURFACE TROUGH THAT
EXTENDS ACROSS THE TURKS AND CAICOS AND W HAITI ALONG 73W TO 18N
GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS N OF 18N
BETWEEN 69W-75W. AN UPPER RIDGE IS ANCHORED OF E BRAZIL COVERING
THE REMAINDER OF THE CARIBBEAN AND INTO THE W TROPICAL ATLC.
UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER RIDGE AND TROUGH IS
SUPPORTING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ACROSS
THE SW CARIBBEAN S OF 10N BETWEEN 78W-83W TO INLAND OVER PANAMA
AND PRODUCING A BAND OF CIRRUS CLOUDS THAT EXTENDS FROM 10N80W
TO OVER PUERTO RICO. MEANWHILE...SURFACE HIGH PRESSURE N OF THE
CARIBBEAN IS RESULTING IN MODERATE/STRONG ELY TRADE WINDS WHICH
ARE FORECAST TO PERSIST THROUGH FRI. THE ABUNDANCE OF TROPICAL
MOISTURE BEING ADVECTED OVER THE E CARIBBEAN COULD PRODUCE
ISOLATED LOW LEVEL SHOWERS MAINLY N OF 16N E OF 69W TO OVER THE
LEEWARD/VIRGIN ISLANDS AS WELL AS PUERTO RICO.

ATLANTIC OCEAN...
A SURFACE TROUGH EXTENDS FROM THE NE COAST OF FLORIDA NEAR
DAYTONA BEACH NORTHWARD TO INLAND OVER SOUTH CAROLINA NEAR
CHARLESTON TO JUST N OF WILMINGTON NORTH CAROLINA GENERATING
HEAVY SHOWERS WITH EMBEDDED THUNDERSTORMS WITHIN 60 NM OF LINE
FROM 31N80W TO 34N77W AND SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS FROM 25N TO 31N W OF 79W INCLUDING THE E PORTION
OF FLORIDA. AN UPPER TROUGH EXTENDS FROM AN UPPER LOW WELL NE OF
BERMUDA THROUGH 32N63W SW TO 25N68W THEN TO AN UPPER LOW JUST N
OF THE WINDWARD PASSAGE...CONTINUING INTO THE CARIBBEAN. A COLD
FRONT ENTERS THE W/CENTRAL ATLC NEAR 32N53W EXTENDING SW TO
28N64W WHERE IT BECOMES STATIONARY ALONG 28N71W TO 31N77W. AS
THIS FRONTAL BOUNDARY IS MOVING INTO AN AREA OF DRIER STABLE AIR
IT CAN ONLY SUPPORT LOW LEVEL ISOLATED SHOWERS WITHIN 60 NM
EITHER SIDE OF THE COLD FRONT. A SURFACE RIDGE ASSOCIATED WITH A
1037 MB HIGH JUST OFF SHORE OF THE CANADIAN MARITIMES EXTENDS SW
BRIDGING THE FRONT DISCUSSED ABOVE THUS WEAKENING IT. A SECOND
SURFACE TROUGH IS IN THE SW ATLC EXTENDING FROM 24N72W ACROSS
THE TURKS AND CAICOS TO OVER W HAITI GENERATING SCATTERED
SHOWERS SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 20N-23N
BETWEEN 70W-77W INCLUDING THE NE COAST OF CUBA. ALTHOUGH THERE
IS AN UPPER TROUGH IN THE E/CENTRAL ATLC...IT IS NOT PRODUCING
ANY SIGNIFICANT WEATHER. IN FACT THE REMAINDER OF THE ATLC W OF
60W IS ENJOYING FAIR WEATHER THIS AFTERNOON AS A SURFACE RIDGE
COVERS THE AREA EXTENDING FROM A PAIR OF 1029 MB HIGH LOCATED
NEAR THE AZORES.

$$
WALLACE





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