[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272356
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST FRI FEB 27 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.

...ITCZ...

FROM THE SOUTHERN COAST OF LIBERIA TO THE EQUATOR ALONG 16W...
TO 2S25W...TO THE EQUATOR ALONG 40W...AND INTO NORTHEASTERN
BRAZIL NEAR 2S49W. ISOLATED AND DISORGANIZED MODERATE SHOWERS
ARE SOUTH OF 5N EAST OF 52W.

...DISCUSSION...

THE GULF OF MEXICO...
THIS AREA IS ON THE EASTERN SIDE OF AN UPPER LEVEL RIDGE
THAT IS CENTERED OVER MEXICO. THIS MEANS THAT WESTERLY-TO-
NORTHWESTERLY WINDS PREVAIL. HIGH CLOUDS ARE NORTH OF 26N
MOVING EASTWARD. DRY AIR IN SUBSIDENCE AT THE UPPER LEVELS
IS EVERYWHERE ELSE. ONE PART OF A SURFACE RIDGE EXTENDS FROM
NORTHERN FLORIDA INTO THE NORTH CENTRAL GULF WATERS. ANOTHER
PART OF A RIDGE EXTENDS FROM NORTHERN FLORIDA INTO THE
NORTHWESTERN CORNER OF THE CARIBBEAN SEA. THE NEXT COLD
FRONT TO AFFECT THIS AREA WILL NOT ARRIVE FOR ANOTHER 24 HOURS
OR SO AND MOVE THROUGH THE AREA DURING THE NEXT 24 TO 30 HOURS
AFTER THAT.

THE CARIBBEAN SEA...
MIDDLE TO UPPER LEVEL NORTHWESTERLY FLOW MOVES INTO THE
NORTHWESTERN CORNER OF THE AREA...FROM THE GULF OF MEXICO.
IT RUNS INTO LARGE SCALE UPPER LEVEL SOUTHWESTERLY-TO-WESTERLY
WIND FLOW WHICH STARTS FROM EL SALVADOR AND NORTHWESTERN
NICARAGUA AND MOVES ACROSS THE WATERS IMMEDIATELY SOUTH OF
THE DOMINICAN REPUBLIC AND ACROSS THE NORTHEASTERN ISLANDS
INTO THE ATLANTIC OCEAN. BROAD LARGE SCALE LOW LEVEL CYCLONIC
FLOW IN THE LOW CLOUD FIELD MOVES UNDER THE UPPER LEVEL FLOW.
PART OF THE MIDDLE TO UPPER LEVEL NORTHWESTERLY FLOW THAT IS
REACHING THE NORTHWESTERN CORNER OF THE AREA EVENTUALLY IS
MOVING THROUGH THE BASE OF THE STILL-EVIDENT MIDDLE TO UPPER
LEVEL TROUGH THAT HAS BEEN DRIVING THE CURRENT ATLANTIC OCEAN
COLD/STATIONARY FRONT. THE BASE OF THIS TROUGH REMAINS ACROSS
THE AREA FROM THE TURKS ISLANDS TO HISPANIOLA.

THE ATLANTIC OCEAN...
A CENTRAL-TO-SOUTHWESTERN NORTH ATLANTIC OCEAN DEEP LAYER
TROUGH IS DRIVING A COLD FRONT THAT PASSES THROUGH 33N40W
TO 30N49W. A STATIONARY FRONT CONTINUES FROM 30N49W TO 26N66W
AND CURVING TO HAITI NEAR 19N73W. BEYOND 25N66W 28N60W 32N54W
ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS ARE WITHIN 120 NM
ON EITHER SIDE OF THE LINE 25N66W 28N60W BEYOND 32N54W.
A SURFACE RIDGE TO THE NORTHWEST OF THE FRONT PASSES THROUGH
33N73W TO NORTHERN FLORIDA INTO THE NORTH CENTRAL GULF OF MEXICO.
SURFACE ANTICYCLONIC FLOW TO THE EAST OF THE FRONT IS AROUND
A RIDGE THAT EXTENDS FROM A 1024 MB HIGH PRESSURE CENTER NEAR
32N34W TO 24N48W TO 17N60W. A TROUGH ON WATER VAPOR IMAGERY
EXTENDS FROM A BROAD CYCLONIC CIRCULATION CENTER NEAR 31N11W
TO 24N15W TO 14N26W. A SURFACE TROUGH EXTENDS FROM A 1012 MB
LOW PRESSURE CENTER NEAR 27N18W TO 25N20W TO 25N24W. THIS IS
WHAT IS LEFT OF THE FRONT FROM THE LAST FEW DAYS.

$$
MT





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