[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230002
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT MON SEP 22 2008

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.

...SPECIAL FEATURES...
A BROAD AREA OF LOW PRESSURE CONTINUES BRINGING HEAVY RAINS TO
PUERTO RICO...E HISPANIOLA...AND ADJACENT WATERS. A 1009 MB
SURFACE LOW HAS BEEN ANALYZED OVER E HISPANIOLA...NEAR
19N68W...BASED ON SAN JUAN WEATHER SERVICE DOPPLER RADAR AND
SATELLITE IMAGERY. SCATTERED MODERATE TO STRONG CONVECTION IS
FROM 14N-20N BETWEEN 64W-70W. THIS ACTIVITY IS BEING ENHANCED BY
UPPER LEVEL DIFFLUENCE IN NORTHWESTERLY FLOW ALOFT. HEAVY
RAINFALL...LIFE-THREATENING FLASH FLOODS...AND MUDSLIDES ARE
EXPECTED TO CONTINUE IMPACTING PUERTO RICO AND THE U.S. VIRGIN
ISLANDS AND HISPANIOLA INTO TUESDAY. UPPER-LEVEL WINDS ARE
EXPECTED TO BECOME A LITTLE MORE FAVORABLE FOR DEVELOPMENT
DURING THE NEXT DAY OR SO...AND THIS SYSTEM STILL HAS THE
POTENTIAL TO BECOME A TROPICAL DEPRESSION AS IT MOVES SLOWLY TO
THE NORTH OR NORTH-NORTHWEST.

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 30W S OF 18N MOVING W 10-15 KT. WAVE
IS EMBEDDED WITHIN A BROAD AREA OF DEEP LAYER MOISTURE AS
INDICATED BY MIMIC TOTAL PRECIPITABLE WATER ANIMATION. RECENT
SATELLITE TRENDS DEPICT WEAK...BROAD LOW/MID-LEVEL CIRCULATION
IN THE VICINITY OF THE WAVE AXIS NEAR 14N. SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION IS E OF THE WAVE AXIS FROM 11N-16N
BETWEEN 25W-30W.

LOW AMPLITUDE TROPICAL WAVE IS ALONG 47W S OF 14N MOVING WEST
10-15 KT. CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION ARE FROM 7N-10N BETWEEN 44W-49W...NEAR THE
INTERSECTION OF THE WAVE AND THE ITCZ.

TROPICAL WAVE IS ALONG 64W S OF 18N MOVING W 10 KT. THIS WAVE
IS MOVING INTO THE AREA OF THE BROAD LOW PRESSURE DESCRIBED IN
THE SPECIAL FEATURES SECTION. SURFACE WINDS AROUND THE LESSER
ANTILLES HAVE VEERED UPON WAVE PASSAGE.

TROPICAL WAVE IS ALONG 80W S OF 16N MOVING W 10-15 KT. AN
INVERTED-V PATTERN IN THE CLOUD ELEMENTS IS NOTED. ISOLATED
SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS.

TROPICAL WAVE IS OVER CENTRAL AMERICA ALONG 90W S OF 20N MOVING
W NEAR 10-15 KT. THIS WAVE EXTENDS S TO THE E PACIFIC. SCATTERED
MODERATE TO ISOLATED STRONG CONVECTION IS FROM 8N-22N BETWEEN
87W-93W.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N13W 8N17W 12N30W 8N40W 11N62W.
BESIDES THE CONVECTION MENTIONED IN THE TROPICAL WAVE SECTION...
SCATTERED MODERATE CONVECTION IS ALONG THE COAST OF W AFRICA
FROM 10N-13N BETWEEN 12W-16W. SIMILAR CONVECTION IS FROM 3N-8N
BETWEEN 35W-39W. ISOLATED MODERATE CONVECTION IS FROM 10N-13N
BETWEEN 36W-43W.

...DISCUSSION...

GULF OF MEXICO...
A SURFACE TROUGH EXTENDS FROM NEAR BROWNSVILLE TEXAS TO THE BAY
OF CAMPECHE ALONG 26N97W 19N95W. WIDELY SCATTERED MODERATE
CONVECTION IS FROM 17N-27N BETWEEN 90W-95W. THIS ACTIVITY IS
BEING ENHANCED BY DIFFLUENCE IN NORTHWESTERLY FLOW ALOFT EAST OF
AN UPPER HIGH NEAR 22N97W. AN UPPER RIDGE EXTENDS EASTWARD FROM
THIS HIGH INTO THE SE GULF NEAR 25N80W. SCATTERED SHOWERS AND
THUNDERSTORM OVER THE E GULF FROM 23N-28N BETWEEN 80W-90W TO
INCLUDE CENTRAL FLORIDA. EXPECT CONTINUED CONVECTION OVER THE
GULF FOR THE NEXT 24 HOURS.

CARIBBEAN SEA...
THE MAIN CONCERN FOR THE NEXT FEW DAYS IS THE AREA OF LOW
PRESSURE DESCRIBED IN THE SPECIAL FEATURES SECTION. THREE
TROPICAL WAVES ARE ALSO OVER THE CARIBBEAN AND CENTRAL AMERICA.
SEE ABOVE. IN ADDITION...SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION IS INLAND OVER N COLOMBIA FROM 3N-12N BETWEEN
70W-78W. SCATTERED MODERATE CONVECTION IS OVER E HONDURAS...AND
E NICARAGUA FROM 13N-17N BETWEEN 84W-86W. SIMILAR CONVECTION IS
OVER CUBA FROM 19N-21N BETWEEN 75W-79W...AND FROM 22N-23N
BETWEEN 80W-83W. AN UPPER HIGH IS OVER THE E CARIBBEAN CENTERED
NEAR 15N62W. THIS UPPER HIGH IS ENHANCING CONVECTION OVER THE E
CARIBBEAN...DISCUSSED IN THE SPECIAL FEATURES SECTION.

ATLANTIC OCEAN...
A SURFACE TROUGH EXTENDS FROM 31N78W TO THE E FLORIDA COAST NEAR
28N80W. SURFACE CONVERGENCE WITH THIS TROUGH IS PROMOTING
SCATTERED SHOWERS OVER THE WESTERN ATLANTIC N OF 29N BETWEEN 76W
AND THE FLORIDA W COAST. A 1023 MB SUBTROPICAL HIGH IS NEAR
33N54W PRODUCING FAIR WEATHER. A 1015 MB LOW IS OVER THE E
ATLANTIC NEAR 32N28W. A SURFACE TROUGH EXTENDS SW FROM THE LOW
TO 30N33W. A WEAK 1018 MB HIGH IS FURTHER S NEAR 26N29W. IN THE
UPPER LEVELS...A RIDGE IS OVER THE W ATLANTIC N OF 20N AND W OF
70W. AN UPPER LEVEL LOW IS CENTERED NEAR 29N63W. ANOTHER UPPER
LEVEL LOW IS CENTERED NEAR 23N43W. AN UPPER LEVEL HIGH IS OVER
THE TROPICAL E ATLANTIC NEAR 16N28W.

$$
FORMOSA


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