[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 101732
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT TUE MAR 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
1715 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N7W 1N20W CROSSING THE EQUATOR
NEAR 28N THEN ALONG 2S35W AND INTO NE BRAZIL NEAR 3S45W.
SCATTERED MODERATE TO STRONG CONVECTION IS WITHIN 60 NM EITHER
SIDE OF THE AXIS BETWEEN THE AFRICAN COAST AND 17W.

...DISCUSSION...

GULF OF MEXICO...
DEEP LAYER RIDGING CONTINUES TO DOMINATE THE GULF THIS
AFTERNOON. A 1022 MB SFC HIGH IN APALACHICOLA BAY IS PROVIDING
LIGHT WINDS OVER THE NE GULF. SOUTHERLY RETURN FLOW OF 15-20 KT
ON THE WESTERN PERIPHERY OF THE SFC RIDGE COVERS THE REMAINDER
OF THE REGION. ALOFT...STRONG SOUTHWESTERLY FLOW IS ADVECTING
MOISTURE ACROSS MEXICO AND INTO THE EASTERN CONUS...
HOWEVER...LITTLE OF THIS MOISTURE IS MAKING ITS WAY INTO THE
GULF AS DRY AIR IS PRESENT ACROSS THE ENTIRE REGION AT ALL
LEVELS. EXPECT LITTLE CHANGE OVER THE NEXT FEW DAYS AS THE DEEP
LAYER RIDGE REMAINS IN PLACE.

CARIBBEAN SEA...
THE PRESSURE GRADIENT BETWEEN A 1023 MB HIGH OVER THE BAHAMAS
AND LOWER PRESSURE OVER SOUTH AMERICA IS GENERATING FRESH TO
STRONG TRADE WINDS ACROSS THE CARIBBEAN. THE TRADE WIND FLOW IS
EXPECTED TO DIMINISH LATER IN THE WEEK AS THE HIGH PRESSURE TO
THE NORTH WEAKENS. LOW-LEVEL CLOUDS AND ISOLATED SHOWERS ARE
RIDING THE TRADE WIND FLOW ACROSS THE EASTERN CARIBBEAN...MAINLY
E OF 72W. THIS CONVECTION IS SHALLOW IN NATURE AS STRONG
SUBSIDENCE AND DRY AIR COVER THE REGION AT THE BASE OF AN UPPER
TROUGH THAT EXTENDS ACROSS THE WINDWARD PASSAGE TO NEAR 14N80W.
LITTLE CHANGE IN THE LARGE SCALE WEATHER PATTERN IS ANTICIPATED
OVER THE NEXT DAY OR SO.

ATLANTIC OCEAN...
THE PREMIER WEATHER FEATURE IN THE DISCUSSION AREA CONTINUES TO
BE THE DEEP-LAYER LOW SPINNING IN THE CENTRAL ATLC. THE 1001 MB
SFC LOW IS CENTERED NEAR 31N41W. A SFC TROUGH EXTENDS AHEAD OF
THE LOW CENTER FROM 30N37W ALONG 25N36W TO 11N47W. MULTI-LEVEL
CLOUDS AND SCATTERED SHOWERS ARE WITHIN 50 NM OF THIS BOUNDARY.
A SECONDARY TROUGH EXTENDS FROM THE LOW CENTER ALONG 28N39W TO
24N41W. CLOUDINESS AND EMBEDDED SHOWERS ARE OBSERVED BETWEEN THE
TWO TROUGHS. SHIP OBSERVATIONS AS WELL AS QUIKSCAT INDICATE GALE
FORCE WINDS ARE STILL PRESENT IN THE EASTERN SEMICIRCLE OF THE
LOW PRESSURE SYSTEM. AS SUCH...A GALE WARNING REMAINS IN EFFECT
WITHIN 240 NM E OF THE LOW CENTER. IN THE W ATLC...A 1023 MB SFC
HIGH OVER THE BAHAMAS CONTINUES TO WEAKEN AS LOW PRESSURE
APPROACHES FROM THE NORTH. A 998 MB SFC LOW CENTERED NEAR 36N60W
EXTENDS A COLD FRONT THAT CLIPS THE NRN PORTION OF THE
DISCUSSION AREA ALONG 32N61W 30N64W 30N70W TO 32N78W. WINDS
CONTINUE TO INCREASE AS THE LOW PRESSURE MOVES SOUTHEASTWARD AND
A GALE WARNING IS EXPECTED WITHIN 24 HOURS N OF 28N BETWEEN
57W-62W. A SFC RIDGE EXTENDS ACROSS THE AZORES TO THE CAPE VERDE
ISLANDS MAINTAINING TRANQUIL CONDITIONS ACROSS THE EAST ATLC.

$$
WADDINGTON




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