[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 211134
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT FEB 21 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1115 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 1N20W 1N30W CROSSING THE
EQUATOR NEAR 40W AND INTO NE BRAZIL NEAR 2S46W. NO DEEP
CONVECTION IS ALONG THE ITCZ AXIS. MUCH OF THE CONVECTIVE
ACTIVITY IS CONCENTRATED SOUTH OF THE EQUATOR TO 6S AND BETWEEN
15W-21W.

...DISCUSSION...

GULF OF MEXICO...
SFC HIGH PRES CENTERED OVER THE SE CONUS EXTENDS A RIDGE SW
TOWARDS THE YUCATAN PENINSULA COVERING MOST OF THE GULF REGION.
NE WINDS OF 20 TO 25 KT ARE NOTED AROUND THE PERIPHERY OF THIS
HIGH AFFECTING THE SE GULF WATERS S OF 25N AND THE YUCATAN
CHANNEL. SOUTHERLY RETURN FLOW IS ALREADY PICKING UP TO 20 KT IN
THE WESTERN GULF OF MEXICO AHEAD OF THE NEXT COLD FRONT
PRESENTLY  MOVING THROUGH THE CENTRAL PLAINS. MULTI-LEVELS
CLOUDS WITH EMBEDDED SHOWERS ARE ALONG THE MEXICAN COAST AND THE
WESTERN PORTION OF THE BAY OF CAMPECHE. THIS CLOUDINESS IS
ASSOCIATED WITH A SHORTWAVE TROUGH LOCATED OVER N-CENTRAL
MEXICO. STRONG W-SW FLOW ALOFT COVERS THE GULF. ACROSS THE
EASTERN GULF...MOSTLY FAIR WEATHER PREVAILS UNDER THE INFLUENCE
OF THE ABOVE MENTIONED SFC HIGH WHICH HAS A PAIR OF 1025 MB
CENTERS...ONE IS OVER NE FLORIDA AND THE OTHER ALONG THE
GEORGIA/ALABAMA BORDER NEAR 33.5N85.5W. THESE CENTERS ARE
EXPECTED TO MERGE THEN THE HIGH WILL SLIDE NE OF THE AREA
THROUGH SAT NIGHT AS A NEW COLD FRONT PUSHES INTO THE NW WATERS
SAT EVENING FOLLOWED BY FRESH TO STRONG NLY WINDS.

CARIBBEAN SEA...
AS OF 0900 UTC...A SFC TROUGH...REMNANTS OF A COLD FRONT...
EXTENDS FROM THE YUCATAN PENINSULA ACROSS THE NW CARIBBEAN INTO
CENTRAL CUBA. SATELLITE IMAGERY SHOWS A NARROW BAND OF CLOUDS
WITH ISOLATED SHOWERS ASSOCIATED WITH THIS TROUGH. NE WINDS OF
20 TO 25 KT ARE EITHER SIDE OF THE TROUGH AXIS. FRESH TO STRONG
TRADE WINDS ARE BLOWING ACROSS THE REMAINDER OF THE BASIN. THESE
WINDS ARE FORECAST TO CONTINUE INTO TUESDAY WITH AN INCREASED
PRESSURE GRADIENT ACROSS THE CARIBBEAN AS HIGH PRESSURE SETTLES
IN BEHIND THE WEAKENING COLD FRONT/TROUGH. GALE CONDITIONS CAN
BE FOUND NEAR THE COAST OF COLOMBIA AND ARE EXPECTED TO CONTINUE
FOR AT LEAST THE NEXT 48 HOURS. PATCHES OF LOW LEVEL MOISTURE
WITH EMBEDDED SHOWERS CONTINUE TO BE ADVECTED WWD ACROSS THE
BASIN ON EASTERLY TRADE WINDS. ALOFT...A RIDGE EXTENDING N FROM
NRN SOUTH AMERICA DOMINATES MUCH OF THE REGION. SWLY FLOW ON THE
WESTERN SIDE OF THE RIDGE ARE NOTED OVER CENTRAL AMERICA...THE
NW CARIBBEAN AND CUBA. THESE WINDS ARE TRANSPORTING SOME
MID/UPPER LEVEL MOISTURE ACROSS THE CENTRAL AND EASTERN
CARIBBEAN. MODERATE TO STRONG SUBSIDENCE IS SEEN OVER CUBA AND
THE FAR NW CARIBBEAN.

ATLANTIC OCEAN...
A DEEP-LAYERED TROUGH ALONG THE EASTERN SEABOARD SUPPORTS A COLD
FRONT THAT ENTERS THE FORECAST AREA NEAR 32N60W THEN CONTINUES
SW ACROSS THE CENTRAL BAHAMAS INTO CENTRAL CUBA WHERE IT IS O
DISSIPATING. LOW LEVEL CONVERGENCE ALONG THE FRONTAL BOUNDARY IS
PROMOTING THE DEVELOPMENT OF SCATTERED SHOWERS WITHIN 60 NM
EITHER SIDE OF THE FRONT. FARTHER TO THE E...A 1032 MB SURFACE
HIGH CENTERED W OF THE AZORES NEAR 39N36W EXTENDS A RIDGE OVER
THE REMAINDER OF THE CENTRAL AND E ATLC. AROUND THE SOUTHERN
PERIPHERY OF THIS RIDGE...MODERATE TO FRESH TRADE WINDS ARE
ADVECTING POCKETS OF LOW LEVEL MOISTURE ACROSS THE TROPICAL
ATLANTIC INTO THE CARIBBEAN SEA. IN THE UPPER-LEVELS...A TROUGH/
RIDGE/TROUGH PATTERN DOMINATES THE ATLANTIC DISCUSSION AREA. THE
RIDGE EXTENDS FROM THE CARIBBEAN INTO THE CENTRAL ATLC TO BEYOND
31N52W. AN UPPER-LEVEL LOW IS NEAR 28N28W GENERATING SCATTERED
SHOWERS N OF 27N BETWEEN 24W-30W. AN UPPER-LEVEL TROUGH
STRETCHES FROM THE LOW TO NEAR 15N45W. STRONG SWLY FLOW IS SEEN
AHEAD OF THIS TROUGH BETWEEN THE CANARY AND THE CAPE VERDE
ISLANDS. AT THE SURFACE...A TROUGH IS ALSO ANALYZED IN THAT AREA
AND RUNS FROM 28N24W TO 32N28W.

$$
GR




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