[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101721
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAY 10 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
1645 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 6N9W 3N19W 1N28W CROSSING THE
EQUATOR NEAR 37W EXTENDING TO NE BRAZIL NEAR 2S46W. SCATTERED
MODERATE CONVECTION IS FROM 3N-5N BETWEEN 4W-6W. SCATTERED
MODERATE CONVECTION IS ALSO S OF 6N BETWEEN 11W-29W. SIMILAR
CONVECTION IS S OF 2N BETWEEN 49W-51W.

...DISCUSSION...

GULF OF MEXICO...
SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT AND DEEP LAYER DRY AIR
ARE PRESENT ACROSS MUCH OF THE GULF REGION. THIS SUBSIDENCE IS
BEING SUPPORTED BY A SURFACE RIDGE OVER THE N GULF THAT EXTENDS
WESTWARD FROM A SURFACE HIGH OVER THE CENTRAL ATLC...AS WELL AS
A 1020 MB SURFACE HIGH OVER THE N GULF NEAR 29N85W. DURING THE
NEXT DAY...THE SURFACE HIGH OVER THE N GULF IS EXPECTED TO
REMAIN STATIONARY AND BE A 1019 MB SURFACE HIGH AT 11/1200 UTC.
THE SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS ARE RESULTING
IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE GULF
REGION. HOWEVER...UPPER LEVEL MOISTURE CONTINUES MOVING
SOUTHEASTWARD ACROSS THE W GULF...WHERE HIGH LEVEL CLOUD
COVERAGE IS INCREASING. THE RETURN FLOW AROUND THE
AFOREMENTIONED SURFACE HIGHS AND SURFACE RIDGE IS RESULTING IN
SE SURFACE WINDS OF 10 TO 15 KT ACROSS MUCH OF THE GULF.
HOWEVER...NE TO E SURFACE WINDS OF 15 TO 20 KT ARE EXPECTED
ACROSS PORTIONS OF THE SW GULF DURING THE NEXT DAY.

CARIBBEAN SEA...
SURFACE HIGH PRESSURE N OF THE CARIBBEAN SEA IS RESULTING IN
FRESH E TRADE WINDS ACROSS THE CARIBBEAN SEA. THESE FRESH E
TRADE WINDS ARE FORECAST TO PERSIST ACROSS THE CARIBBEAN SEA
THROUGH THE WEEK. THE STRONGEST WINDS ARE FOUND NEAR THE COAST
OF COLOMBIA...WHERE NE TO E WINDS OF 20 TO 25 KT ARE OCCURRING.
THE TRADE WINDS ARE ADVECTING POCKETS OF LOW LEVEL MOISTURE WITH
ISOLATED SHOWERS WESTWARD ACROSS THE CARIBBEAN. THE GREATEST
CONCENTRATION OF THESE SHOWERS IS FROM 15N-18N BETWEEN 63W-67W.
ALSO...A BROAD UPPER LEVEL RIDGE IS PRESENT ACROSS THE CARIBBEAN
SEA. ATMOSPHERIC STABILITY ASSOCIATED WITH THIS RIDGE IS
RESULTING IN GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF
THE CARIBBEAN. HOWEVER...UPPER LEVEL DIVERGENCE ASSOCIATED WITH
THE UPPER LEVEL RIDGE IS RESULTING IN SCATTERED SHOWERS AND
ISOLATED THUNDERSTORMS OVER THE SW CARIBBEAN S OF 12N BETWEEN
76W-84W INCLUDING PORTIONS OF COSTA RICA...PANAMA....AND NW
COLOMBIA. ALSO...UPPER LEVEL MOISTURE AND HIGH LEVEL CLOUDS
CONTINUE TO STREAM NORTHEASTWARD ACROSS THE E AND S CARIBBEAN.

ATLANTIC OCEAN...
A SURFACE RIDGE ASSOCIATED WITH A 1025 MB SURFACE HIGH OVER THE
CENTRAL ATLC NEAR 31N49W IS AFFECTING MUCH OF THE ATLC PORTION
OF THE DISCUSSION AREA. THIS SURFACE HIGH IS FORECAST TO MOVE
SOUTHEASTWARD DURING THE NEXT DAY AND BE LOCATED NEAR 30N48W AS
A 1024 MB SURFACE HIGH AT 11/1200 UTC. SUBSIDENCE ASSOCIATED
WITH THE SURFACE HIGH AND SURFACE RIDGE ARE RESULTING IN
GENERALLY FAIR WEATHER CONDITIONS ACROSS MUCH OF THE ATLC
PORTION OF THE DISCUSSION AREA. HOWEVER...POCKETS OF LOW LEVEL
MOISTURE WITH ISOLATED SHOWERS ARE MOVING WESTWARD ACROSS
PORTIONS OF THE SW NORTH ATLC...WITH THE GREATEST OF THESE
SHOWERS S OF 25N BETWEEN 73W-80W INCLUDING PORTIONS OF CUBA AND
THE BAHAMAS. THIS ACTIVITY IS BEING SUPPORTED BY ATMOSPHERIC
INSTABILITY ASSOCIATED WITH AN UPPER LEVEL TROUGH WITH AN AXIS
EXTENDING FROM 23N82W TO 26N78W TO 29N75W. ALSO...A
MID/UPPER-LEVEL TROUGH N OF THE DISCUSSION AREA IS ASSOCIATED
WITH A SURFACE COLD FRONT OVER THE E ATLC THAT EXTENDS FROM
30N35W TO 30N29W TO 32N21W TO NE OF THE DISCUSSION AREA. THIS
COLD FRONT IS DISSIPATING W OF 24W. LOW LEVEL CONVERGENCE IS
SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS
COLD FRONT. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS
PRESENT S OF 11N E OF 57W...WITH AN UPPER LEVEL HIGH NEAR 7N38W.
UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER LEVEL RIDGE AND
UPPER LEVEL HIGH IS ENHANCING THE CONVECTION ASSOCIATED WITH THE
ITCZ.

$$
COHEN


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