000 AXNT20 KNHC 202354 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAY 20 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. ...TROPICAL WAVES... A WEAK TROPICAL WAVE IS ALONG 64W S OF 12N MOVING WEST NEAR 15 KT. ALTHOUGH THE WAVE IS DIFFICULT TO DISCERN ON VISIBLE SATELLITE IMAGERY...ISOLATED SHOWERS ACCOMPANY THE WAVE ACROSS VENEZUELA. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 10N14W 5N20W...CROSSING THE EQUATOR NEAR 28W AND INTO NE BRAZIL NEAR 3S42W. CLUSTERS OF WIDELY SCATTERED MODERATE CONVECTION ARE S OF 6N BETWEEN 21W-29W. ...DISCUSSION... GULF OF MEXICO... AS OF 2100 UTC...A 1006 MB LOW IS CENTERED NEAR 25N85W IN THE SE GULF. A SURFACE TROUGH EXTENDS FROM NEAR SARASOTA TO HOMESTEAD FLORIDA AND ACROSS THE ERN STRAITS OF FLORIDA INTO THE WRN CARIBBEAN. DOPPLER RADAR MOSAIC AND LIGHTNING DATA INDICATE NUMEROUS SHOWERS AND SCATTERED TSTMS COVER MUCH OF FLORIDA AND THE ERN GULF WATERS N OF 23N E OF 90W. THIS SURFACE LOW CONTINUES TO SPIN UNDER AN UPPER LEVEL LOW CENTERED NEAR 26N82W WITH WATER VAPOR IMAGERY SHOWING A NARROW RIBBON OF DRIER AIR ROUGHLY 150 TO 200 NM WIDE WRAPPING AROUND THE WRN AND SRN EXTENT OF THE UPPER LOW. AS THE SURFACE LOW MOVES INTO THE CENTRAL GULF...STRONG N TO NE WINDS TO GALE FORCE ARE EXPECTED N OF 27N E OF 88W. A NARROW SURFACE RIDGE OF HIGH PRESSURE IS CURRENTLY ACROSS THE FAR WRN GULF WITH AXIS ALONG 96W AND WILL GRADUALLY WEAKEN THROUGH EARLY FRIDAY AS THE LOW DRIFTS N-NW TO THE N/CENTRAL GULF COAST BY LATE SATURDAY. CARIBBEAN SEA... A SURFACE TROUGH EXTENDS FROM THE ERN STRAITS OF FLORIDA ACROSS CENTRAL CUBA INTO THE NW CARIBBEAN ALONG 22N80W 18N82W 14N83W. WHILE MOST OF THE CONVECTIVE ACTIVITY REMAINS NORTH OF CUBA... LOW-LEVEL CONVERGENCE ALONG AND E OF THE SURFACE TROUGH IS GENERATING ISOLATED SHOWERS WITHIN 120 NM OF THE BOUNDARY WITH MORE SCATTERED SHOWERS AND TSTMS ACROSS THE N-CENTRAL CARIBBEAN N OF 15N BETWEEN 64W-78W. ALOFT...THIS AREA OF CONVECTION IS BEING AIDED BY THE PRESENCE OF UPPER LEVEL DIFFLUENCE ACROSS FAR ERN CUBA...HISPANIOLA AND THE N/CENTRAL CARIBBEAN SEA. LOCALIZED FLOODING IS EXPECTED TO CONTINUE ACROSS MUCH OF HAITI AND THE DOMINICAN REPUBLIC OVER THE NEXT 24 HOURS. ELSEWHERE...SCATTERED MODERATE TO STRONG CONVECTION IS OVER INLAND PANAMA AND NRN COLOMBIA AS THE ITCZ AXIS EXTENDS FROM THE E PACIFIC REGION ALONG 7N TO A 1007 MB COLOMBIAN LOW NEAR 11N72W. ATLANTIC OCEAN... THE AFOREMENTIONED UPPER LOW ACROSS THE ERN GULF OF MEXICO IS CREATING A LARGE AREA OF UPPER DIFFLUENCE ACROSS THE W ATLC N OF 26N E OF 67W. NUMEROUS SHOWERS AND ISOLATED TSTMS ARE ACROSS THE NW BAHAMAS...FLORIDA PENINSULA AND NEARBY W ATLC WATERS DUE TO LOW LEVEL CONVERGENCE AND MIDDLE TO UPPER LEVEL ATMOSPHERIC INSTABILITY. GALE FORCE ELY WINDS ARE PRESENTLY N OF 28N W OF 76W. AN ABUNDANCE OF LOW-LEVEL TROPICAL MOISTURE AND UPPER DIFFLUENCE IS GENERATING NUMEROUS SHOWERS AND ISOLATED TSTMS ACROSS HISPANIOLA...PUERTO RICO AND THE W ATLC FROM 18N-27N BETWEEN 64W-73W. A LINGERING SURFACE TROUGH IS OVER THE CENTRAL ATLANTIC ALONG 26N45W 23N50W 21N57W 21N63W. SCATTERED SHOWERS ARE OBSERVED WITHIN 60 NM EITHER SIDE OF THE TROUGH. THIS TROUGH IS ASSOCIATED WITH AN UPPER LOW CENTERED NEAR 31N50W AND A 1014 MB SURFACE LOW CENTERED NEAR 30N55W THAT IS GENERATING SCATTERED SHOWERS N OF 27N BETWEEN 42W-54W. ACROSS THE E ATLC...AN UPPER TROUGH IS N OF THE AREA WITH AXIS ALONG 36N23W 24N33W. A SURFACE COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N22W AND CONTINUES ALONG 30N24W 28N30W 29N35W. SCATTERED SHOWERS ARE LOCATED WITHIN 60 NM EITHER SIDE OF THE FRONTAL BOUNDARY. ELSEWHERE...SURFACE RIDGING REMAINS ACROSS THE CENTRAL AND ERN ATLC S OF 25N E OF 45W WITH NELY WINDS OF 10 TO 15 KT NOTED ACROSS THE TROPICAL ATLC WATERS. $$ HUFFMAN