[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 040546
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT MON MAY 04 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
0515 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 4N7W 1N20W TO THE EQUATOR AT 35W AND INTO
NE BRAZIL NEAR 2S45W. SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS ALONG THE COAST OF LIBERIA AND ADJACENT COASTAL
WATERS FROM 1N-7N BETWEEN 6W-9W. SIMILAR CONVECTION IS FROM THE
EQUATOR TO 3N BETWEEN 31W-36W.

...DISCUSSION...

GULF OF MEXICO...
THE COMBINATION OF BROAD SURFACE LOW PRESSURE ACROSS THE MEXICAN
PLATEAU AND A SURFACE RIDGE EXTENDING FROM THE W ATLC ACROSS THE
FLORIDA PENINSULA INTO THE NRN GULF IS PRODUCING SE WINDS FROM
10 TO 20 KT. NO ORGANIZED AREAS OF DEEP CONVECTION ARE OCCURRING
OVER THE GULF...HOWEVER A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH
IS MOVING ACROSS THE SE CONUS AND IS SUPPORTING A COLD FRONT
THAT IS POSITIONED INLAND ALONG THE TEXAS GULF COAST. THIS FRONT
IS FORECAST TO GRAZE THE NW GULF WATERS OVER THE NEXT 24 HOURS
BEFORE WEAKENING SLIGHTLY AND LIFTING NORTHWARD AS A STATIONARY
BOUNDARY. UPPER LEVEL WINDS WILL CONTINUE TO TRANSITION TO MORE
OVERALL ZONAL FLOW AS THE SHORTWAVE TROUGH LIFTS TO THE NE. ONLY
A BAND OF CIRRUS CLOUDS STRETCH ACROSS THE NE GULF ON DIFFLUENT
FLOW LOCATED ACROSS THE ERN GULF AND FLORIDA.

CARIBBEAN SEA...
FRESH TRADEWINDS REMAIN ACROSS THE CARIBBEAN AS THE ANALYZED
PRESSURE FIELD CONTINUES TO EXHIBIT A RELATIVELY RELAXED
GRADIENT. A SURFACE TROUGH EXISTS IN THE ERN CARIBBEAN EXTENDING
FROM THE ANEGADA PASSAGE SWD ALONG 64W TO THE NE COAST OF
VENEZUELA. SCATTERED SHOWERS ARE AFFECTING THE LESSER ANTILLES
AND NE CARIBBEAN MAINLY N OF A SAINT LUCIA TO ERN PUERTO RICO
LINE...AS OBSERVED FROM THE GUADELOUPE...MARTINIQUE AND PUERTO
RICO RADARS. ELSEWHERE...AN UPPER LEVEL HIGH CENTERED OVER NRN
COLOMBIA EXTENDS RIDGING TO THE NW ACROSS CENTRAL AMERICA AS FAR
N AS BELIZE. UPPER DIFFLUENCE IS GENERATING A FEW ISOLATED
SHOWERS AND TSTMS ACROSS CENTRAL AMERICA WITH MORE SCATTERED
ACTIVITY INLAND ACROSS NRN SOUTH AMERICA. DEBRIS MOISTURE FROM
THE DEEP CONVECTION OVER COLOMBIA AND VENEZUELA...IN THE FORM OF
CIRRUS CLOUDS...IS SPREADING NE ACROSS THE CARIBBEAN S OF 18N.

ATLANTIC OCEAN...
THE ATLANTIC IS DOMINATED BY A SURFACE HIGH PRESSURE CENTERED
WELL NORTH OF THE DISCUSSION AREA NEAR 46N23W WITH RIDGING
EXTENDING WEST-SOUTHWESTWARD TO 32N58W AND TO THE FLORIDA
PENINSULA. TWO SMALLER SCALE FEATURES ARE OF INTEREST WHICH ARE
EMBEDDED WEAKNESSES WITHIN THE SURFACE RIDGE. THE FIRST IS A
SURFACE TROUGH N OF PUERTO RICO ALONG 67W FROM ROUGHLY 19N TO
27N. THIS TROUGH HAS BEEN PROGRESSING W-NW WITH A MIDDLE TO
UPPER LEVEL LOW OBSERVED ON WATER VAPOR IMAGERY W OF THE SURFACE
TROUGH CENTERED NEAR 27N70W. SCATTERED SHOWERS ARE PRESENT
WITHIN 90 NM OF A LINE FROM 21N62W TO 28N68W. THE SURFACE WINDS
ARE ENHANCED E OF THE TROUGH AXIS WITH E TO SE WINDS OF UP TO 20
KT. THE SECOND FEATURE IS A SURFACE TROUGH EXTENDING FROM 26N38W
TO BEYOND 32N42W. SCATTERED SHOWERS ARE OCCURRING WITHIN 300 NM
E OF THE TROUGH AXIS N OF 27N. A BOARD UPPER LOW CENTERED NEAR
32N38W ASSOCIATED WITH THE SURFACE TROUGH DOMINATES THE UPPER
LEVEL WINDS OVER MOST OF THE CENTRAL ATLC WITH CYCLONICALLY
TURNING WINDS OBSERVED AS FAR S AS 10N. FINALLY...THERE IS AN
ENHANCEMENT OF NELY SURFACE WINDS OF 20-25 KT NORTHEAST OF THE
CAPE VERDE ISLANDS TO THE WEST COAST OF MAURITANIA AND SENEGAL.
OVER THE NEXT FEW DAYS...THE SURFACE TROUGH N OF PUERTO RICO IS
FORECAST TO CONTINUE MOVING NORTHWESTWARD...WHILE THE TROUGH IN
THE CENTRAL ATLANTIC SHOULD GRADUALLY FILL.

$$
HUFFMAN


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