[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 081748
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT SUN MAR 08 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W CROSSING THE EQUATOR NEAR
20W EXTENDING TO 1S40W AND INTO NE BRAZIL NEAR 3S44W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-6N BETWEEN
2W-10W. ISOLATED MODERATE CONVECTION IS S OF 1N BETWEEN 18W-23W
AND BETWEEN 33W-39W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER LEVEL RIDGE DOMINATES MUCH OF THE GULF AND SE CONUS
WITH MODERATE TO STRONG SUBSIDENCE IN PLACE OVER THE REGION SE
OF A LINE FROM NEW ORLEANS LOUISIANA TO BROWNSVILLE TEXAS.
SOUTHEASTERLY SURFACE RETURN FLOW OF UP TO 25 KT RESIDES ON THE
WRN PERIPHERY OF A SURFACE RIDGE THAT EXTENDS FROM A 1027 MB
HIGH IN THE W ATLC NEAR 29N71W. FRESH EASTERLIES CONTINUE TO
FILTER THROUGH THE STRAITS OF FLORIDA AND INTO THE FAR SE GULF.
THESE WINDS ARE TRANSPORTING PATCHES OF LOW-LEVEL CLOUDS WITH
POSSIBLE ISOLATED SHOWERS ACROSS THE FLORIDA KEYS AND ADJACENT
COASTAL WATERS. THE SURFACE HIGH IS FORECAST TO REMAIN NEARLY
STATIONARY AND AS A RESULT...THE OVERALL WEATHER PATTERN ACROSS
THE GULF WILL CHANGE LITTLE THROUGH LATE TUESDAY. LOOKING
AHEAD...THE NEXT COLD FRONT IS POSITIONED TO IMPACT THE GULF
LATE WEDNESDAY AND WILL LIE EAST-WEST ALONG THE NRN GULF COAST.

CARIBBEAN SEA...
FRESH TO STRONG WINDS ASSOCIATED WITH A 1027 MB SURFACE HIGH
CENTERED IN THE W ATLC NEAR 29N71W ARE ADVECTING POCKETS OF
SHALLOW MOISTURE WITH EMBEDDED ISOLATED LIGHT SHOWERS ACROSS THE
GREATER ANTILLES ISLANDS AND MUCH OF THE CARIBBEAN SEA. AN
EARLIER QUIKSCAT PASS SHOWED E-NE WINDS OF 20-30 KT OVER MUCH OF
THE REGION. ALSO...A GALE WARNING REMAINS IN EFFECT FOR THE SW
CARIBBEAN FROM 10N-13N BETWEEN 74W-77W OFF THE COLOMBIAN COAST.
THE INCREASED SURFACE WINDS ARE THE RESULT OF A TIGHT SURFACE
PRESSURE GRADIENT BETWEEN THE AFOREMENTIONED HIGH OVER THE W
ATLC AND LOWER PRESSURE OVER NRN SOUTH AMERICA. ALOFT...STRONG
SUBSIDENCE IS RESULTING FROM CONFLUENCE IN WESTERLY UPPER LEVEL
FLOW...MAXIMIZED OVER THE ERN CARIBBEAN...AND IT IS THIS UPPER
LEVEL REGIME THAT CONTINUES TO LIMIT ANY DEEP CONVECTION ACROSS
THE BASIN.

ATLANTIC OCEAN...
A DEEP LAYERED TROUGH IS OVER THE CENTRAL ATLC WITH AN ELONGATED
UPPER-LEVEL LOW CENTERED NEAR 28N49W. THIS TROUGH SUPPORTS A
1004 MB OCCLUDED SURFACE LOW CENTERED NEAR 27N51W. THE ATTENDANT
COLD FRONT EXTENDS FROM 29N48W ALONG 24N45W 20N45W SW TO 10N53W.
SCATTERED SHOWERS ARE WITHIN 90 NM OF THE COLD FRONT WHILE UPPER
LEVEL DIFFLUENCE TO THE NE OF THE LOW IS AIDING IN GENERATING
SCATTERED MODERATE CONVECTION E OF THE COLD FRONT FROM 22N-33N E
OF 38W. ACROSS THE W ATLC...A RELATIVELY COOLER AND DRIER
AIRMASS REMAINS IN PLACE WITH A 1027 MB SURFACE HIGH CENTERED
NEAR 29N71W. BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE NOTED ON
SATELLITE IMAGERY ACROSS THE W ATLC INTO THE BAHAMAS AND CUBA
UNDER PREVAILING E-NE FLOW. FARTHER TO THE EAST...AN UPPER-LEVEL
LOW CONTINUES TO SPIN OVER THE E ATLC JUST NORTH OF THE CANARY
ISLANDS. A WEAK 1013 MB SURFACE LOW IS CENTERED NEAR 29N16N WITH
A SURFACE TROUGH ANALYZED FROM THE LOW ALONG 28N14W 25N14W TO
19N17W. ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS TROUGH IS
SUPPORTING AN AREA OF SCATTERED SHOWERS OVER SRN MOROCCO. ACROSS
THE TROPICAL ATLC...A BROAD UPPER-LEVEL RIDGE CENTERED NEAR
6N17W IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ.

$$
HUFFMAN




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