[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 270002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT TUE MAY 26 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
2330 UTC.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 70W S OF 14N MOVING W 15-20 KT. WAVE
POSITION BASED ON PROPAGATION CONTINUITY AS IT REMAINS DIFFICULT
TO DEPICT ON SATELLITE IMAGERY. TOTAL PRECIPITABLE WATER PRODUCT
FROM CIMSS SHOWS DECREASING MOISTURE AS THE WAVE CONTINUES
WESTWARD ACROSS NORTHERN VENEZUELA.

...THE ITCZ...
THE ITCZ AXIS IS CENTERED ALONG 7N12W 5N20W 1N30W CROSSING THE
EQUATOR NEAR 34W AND INTO NE BRAZIL NEAR 2S45W. ISOLATED
MODERATE CONVECTION IS WITHIN 30 NM OF THE AXIS BETWEEN 19W-26W.
A LARGE CLUSTER OF SCATTERED MODERATE/ISOLATED STRONG
CONVECTION IS FROM 5S-3N BETWEEN 26W-35W.

...DISCUSSION...

GULF OF MEXICO...
SCATTERED SHOWERS AND THUNDERSTORMS CONTINUE TO IMPACT THE NE
GULF THIS EVENING. AN UPPER LEVEL TROUGH PRESENT ACROSS THE NE
GULF EXTENDS OVER FLORIDA AND INTO THE W ATLC. ASSOCIATED
DIFFLUENCE IN THE MID AND UPPER LEVELS COMBINED WITH LOW-LEVEL
MOISTURE CONVERGENCE IS SUPPORTING THIS CONVECTIVE ACTIVITY N OF
26N AND E OF 87W. SCATTERED SHOWERS MOVING OFF THE TEXAS COAST
CONTINUE TO DISSIPATE ACROSS THE NW GULF AS THEY ENCOUNTER DRIER
AIR ALOFT IN THE SUBSIDENT ATMOSPHERE ON THE BACK SIDE OF THE
AFOREMENTIONED UPPER TROUGH. ACROSS THE SRN GULF... DEEP LAYER
DRY AIR IN WLY FLOW ALOFT IS SUPPORTING GENERALLY FAIR WEATHER.
LIGHT SLY RETURN FLOW IS OBSERVED ACROSS THE SW GULF AND BAY OF
CAMPECHE. AREAS OF SMOKE AND HAZY CONDITIONS S OF 25N W OF 86W
ARE A RESULT OF WILDFIRES ACROSS SRN MEXICO AND THE YUCATAN
PENINSULA.

CARIBBEAN SEA...
HIGH PRESSURE IN THE W ATLC IS MAINTAINING STRONG E TO SE WIND
FLOW ACROSS THE CARIBBEAN. THE SOUTHEASTERLY FLOW IS GENERATING
AFTERNOON SHOWERS AND THUNDERSTORMS ACROSS THE GREATER ANTILLES
AND NORTHERN LEEWARD ISLANDS.THIS ACTIVITY IS BEING SUPPORTED BY
UPPER LEVEL DIVERGENCE AND DEEP LAYER MOISTURE NEAR AND TO THE
EAST OF THE BASE OF AN UPPER LEVEL TROUGH EXTENDING FROM THE ERN
GULF OF MEXICO TO THE BAHAMAS. AN UPPER LEVEL DIFFLUENT PATTERN
AROUND AN UPPER HIGH OVER THE EAST PACIFIC IS GENERATING
ISOLATED SHOWERS AND THUNDERSTORMS IN THE SW CARIBBEAN S OF 12N.
THE NW CARIBBEAN REMAINS RELATIVELY CLEAR UNDER MODERATE
SUBSIDENCE ALOFT. IN ADDITION...A TROPICAL WAVE IS OVER THE
S/CENTRAL CARIBBEAN ALONG 70W. PLEASE SEE TROPICAL WAVE SECTION
ABOVE FOR FURTHER INFORMATION.

ATLANTIC OCEAN...
SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS ARE OBSERVED ALONG
A SURFACE TROUGH THAT EXTENDS FROM 32N77W INTO A 1010 MB LOW
NEAR 31N75W AND CONTINUES TO 26N74W. THIS CONVECTION IS BEING
ENHANCED BY UPPER LEVEL DIVERGENCE ALONG THE LEADING EDGE OF AN
UPPER TROUGH. THE LOW AND ASSOCIATED SFC TROUGH ARE FORECAST TO
MOVE NORTH OF THE DISCUSSION AREA OVER THE NEXT 24 HOURS.
ADDITIONAL CONVECTION IS FLARING UP OVER THE EASTERN BAHAMAS AT
THE EXIT REGION OF A WEAK WESTERLY JET ALONG THE BASE OF THE
AFOREMENTIONED TROUGH. FURTHER EAST...A 1023 MB SFC HIGH IS
CENTERED NEAR 31N62W. THE PRESENCE OF THIS HIGH PRESSURE IS
LIMITING THE SOUTHWARD EXTEND OF A COLD FRONT NORTH OF THE
REGION. STRONG SUBSIDENCE IS MAINTAINING FAIR WEATHER IN THE
VICINITY OF THIS HIGH. UPPER LEVEL TROUGHING IS PRESENT ACROSS
THE CENTRAL ATLC. AN ASSOCIATED WEAK 1019 MB SURFACE LOW IS
CENTERED NEAR 29N50W...HOWEVER...LITTLE CONVECTION IS OBSERVED.
A SURFACE RIDGE IS PRESENT ACROSS THE E ATLC. UPPER LEVEL
DIVERGENCE ASSOCIATED WITH AN UPPER HIGH NEAR 5N30W IS ENHANCING
CONVECTION ALONG THE ITCZ.

$$
WADDINGTON





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