000 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