[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 152345
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT FRI MAY 15 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 3N10W 1N26W CROSSING THE
EQUATOR NEAR 31W AND CONTINUING INTO NE BRAZIL NEAR 3S40W.
SCATTERED MODERATE TO STRONG CONVECTION IS ALONG THE W AFRICA
COAST FROM 7N-12N BETWEEN 11W-15W. ELSEWHERE...SCATTERED
MODERATE CONVECTION IS S OF 3N BETWEEN 36W-47W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER RIDGE ANCHORED IN THE E PACIFIC REGION COVERS MOST OF
THE GULF THIS EVENING WITH ONLY A MIDDLE TO UPPER LEVEL SHORT-
WAVE TROUGH OVER THE NE GULF MOVING ACROSS THE FLORIDA
PENINSULA. THIS TROUGH SUPPORTS A SURFACE TROUGH THAT AT 2100
UTC EXTENDS FROM SARASOTA FLORIDA ACROSS WRN CUBA INTO THE WRN
CARIBBEAN. LOW-LEVEL CONVERGENCE ALONG WITH UPPER DIFFLUENCE IS
GENERATING SCATTERED SHOWERS AND TSTMS ALONG THE IMMEDIATE
FLORIDA GULF COAST AS WELL AS OVER CUBA AND ADJACENT SE GULF
WATERS. THIS CONVECTIVE ACTIVITY EXTENDS NW OVER THE FLORIDA
PANHANDLE AND SRN SE CONUS INLAND FROM THE GULF COAST WITHIN 90
NM. ELSEWHERE...FAIR WEATHER DOMINATES THE REGION WITH SHIP AND
BUOY OBSERVATIONS INDICATING 10-15 KT E TO SE WINDS OVER THE WRN
GULF AND LIGHTER WINDS OVER THE NE GULF DUE TO PROXIMITY OF THE
SURFACE RIDGE AXIS ORIENTED ALONG THE NRN GULF. THIS PATTERN IS
EXPECTED TO REMAIN IN PLACE FOR THE NEXT FEW DAYS UNTIL THE NEXT
FRONT ENTERS THE NW GULF LATE SAT/EARLY SUN.

CARIBBEAN SEA...
THE WRN CARIBBEAN IS DOMINATED BY AN UPPER TROUGH WITH AXIS
ALONG 77W. THIS UPPER TROUGH IS SUPPORTING A SURFACE TROUGH THAT
AT 2100 UTC EXTENDS FROM SARASOTA FLORIDA ACROSS WRN CUBA TO
NEAR 18N80W. THIS SURFACE TROUGH CONTINUES TO MOVE W-NW AND
GENERATE SCATTERED SHOWERS AND TSTMS N OF 16N BETWEEN 70W AND
THE TROUGH AXIS ALONG 82W. THIS INCLUDES THE GREATER ANTILLES
AND THE ADJACENT NEARBY COASTAL WATERS. UPPER DIFFLUENCE LOCATED
E OF THE UPPER TROUGH IS ALSO PROVIDING SUPPORT FOR SCATTERED
SHOWERS ACROSS THE ERN CARIBBEAN BETWEEN 63W-73W. AN UPPER RIDGE
IS ANCHORED N OF BRAZIL OVER THE TROPICAL ATLC NEAR 6N42W AND
EXTENDS AN UPPER RIDGE W-NW OVER NRN SOUTH AMERICA. UPPER LEVEL
DIFFLUENCE BETWEEN THE UPPER RIDGE AND TROUGH IS SUPPORTING
SCATTERED SHOWERS ACROSS THE SW CARIBBEAN S OF 11N TO INLAND
OVER PANAMA AND COSTA RICA. A BAND OF CIRRUS CLOUDS IS ALSO
OBSERVED THAT EXTENDS FROM 11N75W TO OVER PUERTO RICO AND THE
LEEWARD ISLANDS. FOR NOW...SURFACE HIGH PRESSURE N OF THE
CARIBBEAN IS RESULTING IN MODERATE TO FRESH ELY TRADE WINDS
WHICH ARE FORECAST TO PERSIST OVER THE NEXT FEW DAYS. POCKETS OF
TROPICAL MOISTURE CONTINUE ADVECTING FROM THE TROPICAL ATLC INTO
THE ERN CARIBBEAN AND COULD RESULT IN ISOLATED LOW LEVEL SHOWERS
MAINLY E OF 72W INCLUDING PORTIONS OF THE LESSER ANTILLES.

ATLANTIC OCEAN...
A MIDDLE TO UPPER LEVEL SHORTWAVE TROUGH IS OVER THE NE GULF OF
MEXICO AND CONTINUES MOVING NE ACROSS NRN FLORIDA GENERATING AN
AREA OF UPPER DIFFLUENCE OVER THE W ATLC. THIS UPPER DIFFLUENCE
IS GENERATING SCATTERED SHOWERS W OF 75W RIDING E-SE SURFACE
WIND FLOW. THIS ACTIVITY IS ALSO FOCUSED ON THE ERN SIDE OF A
SURFACE TROUGH THAT EXTENDS FROM SARASOTA FLORIDA ACROSS WRN
CUBA INTO THE WRN CARIBBEAN. A DEEP LAYERED LOW CENTERED NEAR
34N53W SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA
NEAR 32N51W AND EXTENDS ALONG 28N53W 25N60W 25N69W. SCATTERED
SHOWERS ARE OBSERVED WITHIN 60 NM EITHER SIDE OF THE FRONT. ALSO
A PRE-FRONTAL TROUGH IS ANALYZED FROM 23N60W TO 30N50W AND
BEYOND 32N50W. LOW-LEVEL CONVERGENCE ALONG WITH MIDDLE TO UPPER
LEVEL DIFFLUENCE IS GENERATING SCATTERED SHOWERS WITH EMBEDDED
TSTMS N OF 27N WITHIN 90/120 NM E OF THE SURFACE TROUGH.
SCATTERED SHOWERS ARE WITHIN 60NM EITHER SIDE OF THE TROUGH S OF
27N. THE REMAINDER OF THE ATLC W OF 50W IS EXPERIENCING FAIR
WEATHER AS A SURFACE RIDGE COVERS THE AREA EXTENDING FROM A 1026
MB HIGH LOCATED SW OF THE AZORES NEAR 35N31W.

$$
HUFFMAN



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