[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 041041
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...THE ITCZ...

THE ITCZ AXIS IS ALONG 6N10W 1N20W CROSSING THE EQUATOR NEAR 23W
AND CONTINUING ALONG 1S30W 1S40W AND INTO NE BRAZIL NEAR 2S44W.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 150 NM N
OF THE AXIS BETWEEN 14W-25W. SIMILAR CONVECTION IS LOCATED FROM
3S TO 3N BETWEEN 30W-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 STATIONARY
FRONT ACROSS SRN ALABAMA...MISSISSIPPI...AND LOUISIANA THAT
CONTINUES TO PRODUCE SCATTERED SHOWERS AND TSTMS INLAND OVER THE
SE CONUS. A COLD FRONT IS ALSO POSITIONED ALONG THE IMMEDIATE
TEXAS GULF COAST. THIS FRONT IS FORECAST TO BRUSH 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 OFF TO THE NE. ONLY A FEW BANDS 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 U.S. VIRGIN ISLANDS SWD ALONG 65W TO THE NE COAST OF
VENEZUELA. SCATTERED SHOWERS ARE AFFECTING THE LESSER ANTILLES
AND NE CARIBBEAN MAINLY N OF A SAINT LUCIA TO WRN 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 AND GUATEMALA. UPPER DIFFLUENCE IS GENERATING A FEW
ISOLATED SHOWERS AND TSTMS ACROSS THE SW CARIBBEAN S OF 11N WITH
MORE SCATTERED ACTIVITY INLAND ACROSS NRN SOUTH AMERICA. DEBRIS
MOISTURE FROM THE CONVECTION OVER COLOMBIA AND VENEZUELA...IN
THE FORM OF SCATTERED CIRRUS CLOUDS...IS SPREADING NE ACROSS
MUCH OF THE CARIBBEAN.

ATLANTIC OCEAN...
THE ATLANTIC IS DOMINATED BY A SURFACE HIGH PRESSURE CENTERED
WELL NORTH OF THE DISCUSSION AREA NEAR 46N21W WITH RIDGING
EXTENDING WEST-SOUTHWESTWARD TO 34N54W 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 NE OF PUERTO RICO ALONG 69W FROM ROUGHLY 21N TO
29N. 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 28N70W. SCATTERED SHOWERS AND ISOLATED
TSTMS ARE PRESENT WITHIN 90 NM OF A LINE FROM 21N62W TO 28N69W.
THE SURFACE WINDS ARE ENHANCED E OF THE TROUGH AXIS WITH E TO SE
WINDS OF UP TO 25 KT. THE SECOND FEATURE IS A SURFACE TROUGH
EXTENDING FROM 25N38W TO BEYOND 32N43W. SCATTERED SHOWERS ARE
OCCURRING E OF THE SURFACE TROUGH FROM 28N-34N BETWEEN 35W-41W.
A BROAD UPPER LOW CENTERED NEAR 31N38W 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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