[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 102348
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2315 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N9W 3N20W 1N30W CROSSING THE
EQUATOR NEAR 36W AND INTO NE BRAZIL NEAR 2S45W. A CLUSTER OF
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE
EQUATOR TO 4N BETWEEN 14W-18W.

...DISCUSSION...

GULF OF MEXICO...
SUBSIDENCE IN NORTHWESTERLY FLOW ALOFT AND DEEP LAYER DRY AIR
ARE PRESENT ACROSS MUCH OF THE GULF...RESULTING IN GENERALLY
FAIR CONDITIONS THROUGHOUT THE REGION. THIS STABLE ATMOSPHERE IS
BEING SUPPORTED BY A BROAD SURFACE RIDGE THAT EXTENDS FROM THE
CENTRAL ATLC WESTWARD ACROSS THE GULF TO CENTRAL MEXICO. A
1021MB SFC HIGH PRESSURE IS CENTERED IN THE NW GULF NEAR 28N86W.
THIS HIGH IS EXPECTED TO REMAIN STATIONARY BUT WEAKEN OVER THE
NEXT DAY OR TWO. SOUTHERLY RETURN FLOW OF 10-15 KT IS OBSERVED
ACROSS THE GULF. ALOFT...ANTICYCLONIC FLOW IS ADVECTING UPPER
LEVEL MOISTURE FROM THE E PACIFIC ACROSS MEXICO AND THE WESTERN
GULF...WHERE HIGH LEVEL CLOUD COVERAGE CONTINUES TO INCREASE.

CARIBBEAN SEA...
SURFACE HIGH PRESSURE IN THE ATLANTIC IS MAINTAINING FRESH TO
STRONG EASTERLY TRADE WINDS ACROSS THE CARIBBEAN SEA. POCKETS OF
LOW LEVEL MOISTURE WITH ISOLATED TRADE WIND SHOWERS ARE MOVING
ACROSS THE CARIBBEAN N OF 13N. LOW LEVEL WIND SPEED CONVERGENCE
COUPLED WITH UPPER LEVEL DIVERGENCE IS GENERATING SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS IN THE SW CARIBBEAN S OF 12N
W OF 77W. ELSEWHERE IN THE CARIBBEAN...ATMOSPHERIC STABILITY
AROUND AN UPPER LEVEL RIDGE IS PROVIDING FAIR WEATHER CONDITIONS.

ATLANTIC OCEAN...
A BROAD SURFACE RIDGE ASSOCIATED WITH A 1025 MB NEAR 30N49W
CONTINUES TO DOMINATE THE WEATHER PATTERN ACROSS THE ATLANTIC.
THE SURFACE HIGH IS FORECAST TO MOVE SOUTHEASTWARD DURING THE 24
HOURS. POCKETS OF LOW LEVEL MOISTURE WITH ISOLATED SHOWERS ARE
OBSERVED MOVING WESTWARD ALONG THE SOUTHERN PERIPHERY OF THE SFC
RIDGE. A CLUSTER OF LOW-MID LEVEL CLOUDS IS OBSERVED ON VISIBLE
SATELLITE IMAGERY FROM 14N-19N BETWEEN 51W-56W. THE 2000 UTC
SFC OBSERVATION FROM A BUOY IN THE REGION SHOWS A DISTINCT NE-SE
WIND SHIFT...INDICATING THE POSSIBILITY OF A LOW-LEVEL TROUGH IN
THE AREA. FURTHER EAST...A DISSIPATING COLD FRONT LIES ACROSS
THE NORTHERN PORTION OF THE DISCUSSION AREA FROM 30N22W ALONG
28N29W TO 30N35W. SCATTERED CLOUDS AND POSSIBLE EMBEDDED SHOWERS
ARE WITHIN 60 NM OF THE BOUNDARY. ACROSS THE TROPICAL ATLC...AN
UPPER LEVEL RIDGE IS PRESENT S OF 10N E OF 56W...WITH AN UPPER
LEVEL HIGH NEAR 6N35W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH
THESE FEATURES IS ENHANCING THE CONVECTION ASSOCIATED WITH THE
ITCZ.

$$
WADDINGTON





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