000 AXNT20 KNHC 210003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUN 20 2012 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...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL ANALYSIS. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...SPECIAL FEATURES... TROPICAL STORM CHRIS IS CENTERED NEAR 38.5N 49.0W AT 20/2100 UTC MOVING E AT 18 KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. MAXIMUM SUSTAINED WIND SPEED IS 50 KT WITH GUSTS TO 60 KT. SCATTERED MODERATE CONVECTION IS OCCURRING WITHIN 120 NM OF CENTER IN ALL QUADRANTS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT3/WTNT23 KNHC FOR MORE DETAILS. AN ELONGATED SURFACE TROUGH EXTENDS FROM THE CENTRAL FLORIDA PENINSULA TO THE NORTHERN YUCATAN PENINSULA ALONG 27N82W TO 21N88W. MARINE AND SURFACE OBSERVATIONS REGISTER A SHARP CYCLONIC TURNING ALONG THE TROUGH AXIS WITH SE WINDS ON THE ERN SIDE OF THE AXIS GUSTING TO 25 KT. LAST VISIBLE PICTURES OF THE DAY REVEALED A LOW LEVEL CIRCULATION EMBEDDED IN THE TROUGH AXIS NEAR 25N85W. DOPPLER RADAR IMAGERY INDICATED SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS S OF 29N E OF 85W INCLUDING THE STRAITS OF FLORIDA. STRONG UPPER-LEVEL WINDS OVER THE GULF OF MEXICO ARE EXPECTED TO GRADUALLY DIMINISH...AND SOME SLOW DEVELOPMENT IS POSSIBLE. THIS SYSTEM HAS A MEDIUM CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS. HEAVY RAINS AND LOCALIZED FLOODING ARE POSSIBLE ACROSS WESTERN CUBA...SOUTHERN FLORIDA...THE CENTRAL BAHAMAS...AND THE YUCATAN PENINSULA THROUGH FRIDAY. ...TROPICAL WAVES... TROPICAL WAVE EXTENDS FROM 16N19W TO 7N23W MOVING W AT 5-10 KT. THE WAVE IS EMBEDDED WITHIN A SURGE OF DEEP MOISTURE ON TOTAL PRECIPITABLE WATER IMAGERY. HOWEVER...NO SIGNIFICANT CONVECTION IS ASSOCIATED WITH THE WAVE AT THIS TIME...DUE TO SAHARAN DUST COVERING MUCH OF THE TROPICAL NORTH ATLC WATERS. ANY CONVECTION TO THE SW OF THE WAVE AXIS IS LIKELY ASSOCIATED WITH THE MONSOON TROUGH AXIS. TROPICAL WAVE EXTENDS FROM 19N64W TO 13N66W MOVING W-NW AT 20-25 KT. THE WAVE IS QUICKLY BECOMING EMBEDDED WITHIN THE LOW-LEVEL TROUGHING THAT IS LOCATED ACROSS THE SW NORTH ATLC. LAST VISIBLE SATELLITE IMAGES OF THE DAY SHOWED NO ACTIVITY IN THE VICINITY OF THE TROUGH AXIS. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE AFRICAN COAST NEAR 11N15W TO 10N19W. THEN IT REAPPEARS W OF A TROPICAL WAVE FROM 8N24W ALONG 6N33W TO 7N41W. THE ITCZ AXIS EXTENDS FROM THIS POINT TO 5N54W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 150 NM ON EITHER SIDE OF THE ITCZ W OF 50W...AND WITHIN 90 NM ON EITHER SIDE OF THE MONSOON TROUGH BETWEEN 25W-40W AND E OF 20W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH AXIS OVER N MEXICO IS HELPING TO ADVECT TROPICAL MOISTURE FROM THE ERN PACIFIC ACROSS MEXICO AND INTO THE WESTERN GULF W OF 90W. UPPER LEVEL DIFFLUENCE IS NOTICED IN THIS REGION BETWEEN THE UPPER TROUGH AND ANTICYCLONIC FLOW CENTERED OVER THE YUCATAN PENINSULA. THIS IS GENERATING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS IN THIS REGION W OF 92W...ESPECIALLY WITHIN 150 NM OFF THE MEXICAN COAST N OF TAMPICO TO THE TEXAS COAST NEAR CORPUS CHRISTI. THE SECOND REGION OF ACTIVE WEATHER IS ASSOCIATED TO AN ELONGATED SURFACE TROUGH DISCUSSED IN THE SPECIAL FEATURES SECTION ABOVE. COMPUTER MODELS SUGGEST THIS SYSTEM WILL CONTINUE TO MOVE WESTWARD AT A SLOW RATE WITH CONVECTION AFFECTING A GREAT PORTION OF THE GULF E OF 90W. CARIBBEAN SEA... SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS REMAIN OVER THE NW CARIBBEAN WATERS N OF 19N W OF 78W...ASSOCIATED TO THE BROAD SURFACE CYCLONIC WIND FIELD FROM THE SURFACE TROUGH OVER ERN GULF OF MEXICO. UPPER LEVEL DIFFLUENT FLOW IS ALSO OVER THIS REGION SUPPORTING THE RAINFALL ACTIVITY. AS THE SURFACE TROUGH SLOWLY MOVES WESTWARD...PERSISTENT CONVECTION IS FORECAST TO CONTINUE ACROSS THE NW CARIBBEAN DURING THE NEXT FEW DAYS. LOCALLY HEAVY RAINFALL WITH THE HIGH POTENTIAL FOR FLOODING AND MUDSLIDES IS LIKELY OVER PORTIONS OF CUBA AND THE YUCATAN PENINSULA DURING THE FORECAST PERIOD. FAIR WEATHER CONDITIONS ARE ACROSS THE REMAINDER OF THE CARIBBEAN THIS EVENING...WITH 10-20 KT EASTERLY TRADES OBSERVED E OF 80W. ATLANTIC OCEAN... WATER VAPOR IMAGERY SHOWS A SHORTWAVE DEVELOPING OVER THE SRN PORTION OF A BROAD UPPER LEVEL TROUGH THAT COVERS THE WESTERN NORTH ATLC W OF 37W SUPPORTING A SURFACE TROUGH ANALYZED FROM 33N65W TO 24N71W. THIS SYSTEM ALONG WITH STRONG DIFFLUENCE ALOFT IS GENERATING A BROAD AREA OF SCATTERED MODERATE TO HEAVY SHOWERS AND THUNDERSTORMS 22N-31N BETWEEN 57W-69W...AS WELL AS FROM 21N-28N BETWEEN 69W-80W. HEAVY RAINS AND LOCALIZED FLOODING ARE POSSIBLE ACROSS THE CENTRAL AND NW BAHAMAS THROUGH FRIDAY. OTHERWISE THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A PAIR OF 1024 MB HIGHS...ONE CENTERED NEAR 27N55W AND THE OTHER CENTERED NEAR 30N37W. THE FAIR WEATHER OVER THIS REGION IS ALSO ASSOCIATED TO SAHARAN DUST DEPICTED ON THE THE METEOSAT-9 SAHARAN AIR LAYER TRACKING PRODUCT. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ GARCIA