[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 240551
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT SUN MAY 24 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.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 48W S OF 10N MOVING W NEAR 18 KT. THIS
WAVE IS ASSOCIATED WITH A MAXIMUM IN DEEP LAYER MOISTURE BASED
ON THE TOTAL PRECIPITABLE WATER PRODUCT FROM CIMSS. SATELLITE
IMAGERY INDICATES THAT THE WAVE IS EMBEDDED WITHIN AN INVERTED-V
CLOUD SIGNATURE...WITH CYCLONIC CIRCULATION IN THE MOTION OF THE
LOW LEVEL CLOUDS IN THE VICINITY OF THE WAVE AXIS. ISOLATED
MODERATE CONVECTION IS WITHIN 250 NM EITHER SIDE OF THE WAVE
AXIS S OF 5N.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 8N12W 4N19W 1N28W CROSSING THE
EQUATOR NEAR 32W EXTENDING JUST S OF THE EQUATOR TO THE COAST OF
NE BRAZIL NEAR 1S47W. ISOLATED MODERATE CONVECTION IS S OF 6N
BETWEEN 14W-21W. SCATTERED MODERATE CONVECTION IS ALSO S OF 3N
BETWEEN 34W-51W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYER TROUGH IS PRESENT ACROSS THE GULF WITH AN AXIS
EXTENDING FROM AN UPPER LOW OVER LOUISIANA NEAR 31N93W TO THE
ERN STRAITS OF FLORIDA NEAR 24N80W. AN ASSOCIATED 1006 MB
SURFACE LOW IS LOCATED INLAND ACROSS SRN MISSISSIPPI NEAR
32N89W...WITH A SURFACE TROUGH EXTENDING FROM THE LOW THROUGH
MOBILE BAY TO 23N86W. LOW LEVEL CONVERGENCE ALONG THE SURFACE
TROUGH...AS WELL AS UPPER LEVEL DIFFLUENCE NE OF THE UPPER
TROUGH AXIS...ARE SUPPORTING SCATTERED SHOWERS AND ISOLATED
TSTMS ACROSS THE BIG BEND REGION OF FLORIDA N OF 29N E OF 85W
AND ALSO FROM 24N-27N BETWEEN 83W-85W IN THE E GULF. UPPER
DIFFLUENCE NEAR THE BASE OF THE UPPER TROUGH IS GENERATING
SCATTERED SHOWERS AND TSTMS ACROSS THE FLORIDA STRAITS E OF 83W.
AS THE SURFACE LOW CONTINUES MOVING NW MAINLY LIGHTLY SOUTHERLY
SURFACE FLOW WILL PREVAIL ACROSS THE ENTIRE GULF THROUGH TUES.
ACROSS THE SW GULF...DEEP LAYER DRY AIR AND SUBSIDENCE
ASSOCIATED WITH W-NW FLOW ALOFT IS SUPPORTING GENERALLY FAIR
WEATHER CONDITIONS.

CARIBBEAN SEA...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING ACROSS THE
CARIBBEAN N OF 17N E OF 80W. THIS ACTIVITY IS BEING SUPPORTED BY
UPPER LEVEL DIFFLUENCE IN MOIST WESTERLY FLOW ALOFT BETWEEN AN
UPPER LEVEL TROUGH EXTENDING FROM THE GULF OF MEXICO TO OVER THE
NW CARIBBEAN...AND AN UPPER LEVEL RIDGE ACROSS THE SW NORTH
ATLC. THIS SYNOPTIC PATTERN HAS PERSISTED FOR THE PAST FEW DAYS
AND IS RESULTING IN CONTINUED PRECIPITATION ACROSS CUBA...
JAMAICA...HISPANIOLA...PUERTO RICO AND THE NEARBY COASTAL WATERS
ACROSS THE NRN CARIBBEAN. THE UPPER TROUGH IS FORECAST TO DRIFT
SLOWLY EWD AND BEGIN WEAKENING BY LATE MONDAY. ADDITIONAL
SCATTERED SHOWERS AND TSTMS ARE OCCURRING ACROSS CENTRAL AMERICA
AND THE SW CARIBBEAN WATERS SW OF A LINE FROM 15N83W TO 10N76W.
THIS ACTIVITY IS BEING SUPPORTING BY UPPER LEVEL DIFFLUENCE ON
THE EXTENSION OF AN UPPER LEVEL RIDGE FROM THE E PACIFIC REGION
EWD TO 67W. MEANWHILE...THE SURFACE PRESSURE GRADIENT S OF A
SURFACE RIDGE OVER THE W ATLC IS MAINTAINING ELY WINDS OF 20 TO
25 KT ACROSS PORTIONS OF THE ERN CARIBBEAN.

ATLANTIC OCEAN...
SCATTERED SHOWERS AND ISOLATED TSTMS ARE OCCURRING SW OF A LINE
FROM 32N81W NEAR THE SRN SOUTH CAROLINA COAST TO N OF THE
LEEWARD ISLANDS NEAR 20N61W. THIS AREA INCLUDES THE BAHAMAS...
TURKS AND CAICOS ISLANDS...GREATER ANTILLES AND ADJACENT NEARBY
COASTAL WATERS ALONG THE ERN FLORIDA PENINSULA. THIS ACTIVITY IS
BEING SUPPORTED BY UPPER LEVEL DIFFLUENCE IN MOIST SWLY FLOW
ALOFT BETWEEN AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO AND
AN UPPER LEVEL RIDGE ACROSS THE SW NORTH ATLC. FARTHER TO THE
E...AN UPPER LEVEL TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM
AN UPPER LEVEL LOW NEAR 32N47W TO 27N55W TO 26N65W. ATMOSPHERIC
INSTABILITY NEAR THE UPPER LEVEL LOW AND TROUGH...AS WELL AS
UPPER LEVEL DIFFLUENCE IN MOIST SOUTHWESTERLY FLOW ALOFT...ARE
SUPPORTING SCATTERED MODERATE CONVECTION N OF 27N BETWEEN
37W-49W. ALSO...A SURFACE TROUGH EXTENDS FROM 31N47W INTO A 1021
MB SURFACE LOW NEAR 29N48W CONTINUING SW INTO A 1017 MB LOW NEAR
23N55W AND CONTINUING ALONG 20N61W TO N OF PUERTO RICO NEAR
19N65W. LOW LEVEL CONVERGENCE NEAR THE SURFACE LOWS AND TROUGH
IS SUPPORTING SCATTERED SHOWERS WITHIN 120/150 NM OF THE TROUGH
AXIS. ACROSS THE E ATLC...A SURFACE RIDGE IS PRESENT WHERE
MAINLY ZONAL FLOW ALOFT IS OCCURRING AND FAIR WEATHER CONDITIONS
PERSIST. ACROSS THE TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF
10N E OF 55W. UPPER LEVEL DIVERGENCE ASSOCIATED WITH THE UPPER
LEVEL RIDGE IS ENHANCING CONVECTION ASSOCIATED WITH THE ITCZ AND
THE TROPICAL WAVE ALONG 48W.

$$
HUFFMAN




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