[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 210543
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0615 UTC.

...THE ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N12W CROSSING THE EQUATOR NEAR
18W EXTENDING TO 4S30W AND INTO NE BRAZIL NEAR 5S36W. MUCH OF
THE CONVECTIVE ACTIVITY IS CONCENTRATED SOUTH OF THE EQUATOR TO
5S AND BETWEEN 15W-21W.

...DISCUSSION...

GULF OF MEXICO...
STRONG WESTERLY FLOW ALOFT COVERS THE GULF IN THE BASE OF A DEEP
TROUGH OVER THE ERN CONUS AND W ATLC. THIS TROUGH SUPPORTS A
COLD FRONT OVER THE W ATLC AND THE CENTRAL BAHAMAS WHICH IS
DISSIPATING OVER CENTRAL CUBA AND THE NW CARIBBEAN. AT THE
SURFACE...A HIGH PRES CENTERED OVER THE SE CONUS DOMINATES THE
ENTIRE GULF. NE WINDS OF 20 TO 25 KT ARE NOTED AROUND THE
PERIPHERY OF THIS HIGH AFFECTING THE SOUTHERN GULF WATERS S OF
25N AND THE YUCATAN CHANNEL. ABUNDANT LOW/MID LEVEL CLOUDS WITH
EMBEDDED LIGHT RAIN ARE BANKING UP AGAINST THE SIERRA MADRE
MOUNTAINS IN MEXICO. ACROSS THE N GULF...MOSTLY CLEAR SKIES ARE
NOTED DUE TO THE PRESENCE OF THE ABOVE MENTIONED SFC HIGH
ANALYZED 1025 MB OVER SRN ALABAMA/WESTERN FLORIDA PANHANDLE.
THIS 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...
A DYING COLD FRONT IS OVER THE NW CARIBBEAN AND CENTRAL CUBA
EXTENDING FROM 20N87W TO 22N78W. SATELLITE IMAGERY SHOWS A
NARROW BAND OF CLOUDS WITH ISOLATED SHOWERS ASSOCIATED WITH THE
FRONTAL BOUNDARY. NE WINDS OF 20 TO 25 KT ARE BEHIND THE FRONT.
FRESH TO STRONG TRADE WINDS ARE BLOWING ACROSS 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. THE STRONGEST WINDS ARE
FOUND ALONG THE COAST OF COLOMBIA...WHERE A GALE WARNING IS
ALREADY IN EFFECT. PATCHES OF LOW LEVEL MOISTURE WITH EMBEDDED
SHOWERS CONTINUE TO BE ADVECTED WWD ACROSS THE BASIN ON EASTERLY
TRADE WINDS. ALOFT...A RIDGE EXTENDING FROM NRN SOUTH AMERICA
DOMINATES MUCH OF THE REGION. SWLY FLOW ON THE WESTERN SIDE OF
THE RIDGE ARE TRANSPORTING SOME MID/UPPER LEVEL MOISTURE ACROSS
THE CENTRAL AND EASTERN CARIBBEAN. MODERATE TO STRONG SUBSIDENCE
IS NOTED OVER CUBA AND THE NW CARIBBEAN.

ATLANTIC OCEAN...
THE DEEP TROUGH OVER THE ERN CONUS AND W ATLC CONTINUES TO
SLOWLY PROGRESS EWD. THE ATTENDANT COLD FRONT ENTERS THE
FORECAST AREA NEAR 31N63W THEN CONTINUES SW ACROSS THE CENTRAL
BAHAMAS INTO CENTRAL CUBA WHERE IT BEGINS TO DISSIPATE. LOW
LEVEL CONVERGENCE IS SUPPORTING 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 38N37W 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 28N30W GENERATING SOME SHOWER
ACTIVITY. A 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.

$$
GR





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