[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 272342
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON APR 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.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 5N9W 2N20W CROSSING THE EQUATOR
AT 25W TO 2S35W INTO NE BRAZIL NEAR 3S46W. CLUSTERS OF MODERATE
TO STRONG CONVECTION ARE NOTED OVER SW AFRICA AND NE BRAZIL.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM THE
EQUATOR TO THE COAST OF AFRICA BETWEEN 3W-6W.

...DISCUSSION...

GULF OF MEXICO...
A LARGE 1032 MB SURFACE HIGH LOCATED OVER THE W ATLC NEAR 33N73W
EXTENDS A RIDGE ACROSS THE FLORIDA STATE INTO THE ENTIRE GULF OF
MEXICO. THIS FEATURE IS PRODUCING FRESH TO STRONG E TO SE FLOW
ACROSS GULF REGION. AN ASCAT PASS FROM AROUND 1600 UTC CONFIRMED
THESE WIND SPEEDS. THE SFC HIGH WILL REMAIN STATIONARY OVER THE
NEXT 24 TO 36 HOURS WHILE GRADUALLY WEAKENING. ALOFT...A DEEP
LAYERED TROUGH EXTENDS ACROSS CENTRAL TEXAS AND NE MEXICO. AN
AREA OF STRONG SHOWERS AND TSTMS IS NOTED OVER TEXAS AHEAD OF
FRONT AND DRY LINE COMPLEX...BUT THIS ACTIVITY SHOULD REMAIN N
OF THE GULF. SOME SHOWER/TSTM ACTIVITY IS ALSO NOTED OVER NE
MEXICO... PARTICULARLY OVER THE STATE OF COAHUILA. OTHERWISE A
SHARP MID/UPPER LEVEL RIDGE EXTENDS FROM THE BAY OF CAMPECHE TO
THE SE CONUS. A NARROW BAND OF MID/UPPER LEVEL MOISTURE IS
BETWEEN THE TROUGH AND THE RIDGE AND GOES FROM CENTRAL MEXICO TO
SE LOUISIANA. GENERALLY SCATTERED CLOUDS PERSIST OVER THE
AREA... EXCEPT FOR BROKEN LOW CLOUDS NEAR THE TEXAS COAST.

CARIBBEAN SEA...
HIGH PRES LOCATED N OF AREA MAINTAINS FRESH TO STRONG SURFACE
WIND ACROSS MUCH OF THE BASIN WITH THE STRONGEST WINDS IN THE
TYPICAL AREA NEAR THE COAST OF COLOMBIA. THIS WEATHER PATTERN
WILL PERSIST DURING THE NEXT 24 HOURS. THE HIGH IS FORECAST TO
GRADUALLY WEAKEN TUE THROUGH FRI. AS A RESULT...THE TRADE WINDS
ARE EXPECTED TO DIMINISH DURING THIS TIME-FRAME. A BROAD UPPER
LEVEL RIDGE COVERS MOST OF THE CARIBBEAN...WITH MOSTLY SW TO W
UPPER LEVEL WINDS. THESE WINDS ARE TRANSPORTING ABUNDANT
MID/UPPER LEVEL MOISTURE FROM THE EPAC REGION ACROSS N CENTRAL
AMERICA INTO THE CARIBBEAN SEA...THEN OVER E CUBA...JAMAICA AND
HISPANIOLA. A SHORT-WAVE TROUGH IS OVER WESTERN CUBA AND THE NW
CARIBBEAN. THIS TROUGH IS HELPING TO INDUCE SOME SHOWER/TSTM
ACTIVITY OVER CUBA. IN ADDITION...LOW-TOPPED TRADE WIND SHOWERS
ARE OBSERVED ACROSS THE REGION...MORE CONCENTRATED OVER THE
EASTERN CARIBBEAN AND JAMAICA. PATCHES OF LOW-LEVEL MOISTURE
WILL CONTINUE TO PROPAGATE ACROSS THE CARIBBEAN SEA PRODUCING
ISOLATED TO SCATTERED PASSING SHOWERS.

ATLANTIC OCEAN...
AS PREVIOUSLY MENTIONED...A LARGE 1032 MB SURFACE HIGH IS JUST N
OF THE AREA NEAR 33N73W. THIS SYSTEM HAS TIGHTENED THE PRES
GRADIENT OVER THE W ATLC WITH 20-25 KT ELY WINDS FROM 20N-27N W
OF 63W INCLUDING THE BAHAMAS AND THE STRAITS OF FLORIDA. A SFC
TROUGH...REMNANTS OF A FRONTAL BOUNDARY...IS ANALYZED ALONG
31N47W 27N51W 24N52W. ISOLATED SHOWERS ARE JUST AHEAD OF THE
TROUGH AXIS MAINLY NEAR 27N51W. THE REMAINDER OF THE DISCUSSION
AREA IS UNDER THE INFLUENCE OF A RIDGE ANCHORED ON A HIGH NEAR
THE AZORES. A BELT OF FRESH TO STRONG NLY WINDS IS BETWEEN THE
CANARY AND THE CAPE VERDE ISLANDS DUE TO THE TIGHT PRES GRADIENT
BETWEEN THIS HIGH AND LOWER PRES OVER AFRICA. A LONG-WAVE TROUGH
OVER THE E-CENTRAL ATLC ENTERS THE FORECAST AREA NEAR 31N45W TO
A CLOSED LOW LOCATED 29N48W...THEN THE TROUGH EXTENDS MAINLY E-W
TO ANOTHER CLOSED LOW LOCATED NE OF THE BAHAMAS NEAR 30N70W.
THIS UPPER-LEVEL PATTERN IS FORECAST TO PERSIST OVER THE NEXT
COUPLE OF DAYS WITH THE WESTERNMOST UPPER LOW MOVING EWD AND THE
ASSOCIATED TROUGH DIGGING SWD INTO THE NORTHERN CARIBBEAN.
COMPUTER MODEL ALREADY ANTICIPATES AN INCREASE IN MOISTURE
ACROSS THE GREATER ANTILLES FROM EASTERN CUBA TO PUERTO RICO AND
OVER THE SE BAHAMAS DUE TO THE PRESENCE OF THIS UPPER-LEVEL
TROUGH.

$$
GR





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