000 AXNT20 KNHC 171748 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT SUN MAY 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 42W/43W S OF 12N MOVING W NEAR 15 KT. A SUBTLE CYCLONIC CURVATURE TO THE LOW-LEVEL CLOUDS IS OBSERVED ON VISIBLE IMAGERY NEAR THE WAVE AXIS AS SURFACE TO 700 MB MODEL DATA ALSO POINTS TO A CYCLONIC PERTURBATION IN THE WIND FIELD. WAVE REMAINS VOID OF ANY DEEP CONVECTION...WITH SCATTERED TO BROKEN MULTILAYERED CLOUDS FROM 3N-9N BETWEEN 38W-45W. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 8N12W 2N20W CROSSING THE EQUATOR NEAR 24W TO NE BRAZIL NEAR 4S39W. SCATTERED MODERATE CONVECTION IS S OF 4N BETWEEN 14W-29W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER-LEVEL TROUGH IS ACROSS THE CENTRAL CONUS AND SUPPORTS A COLD FRONT THAT AS OF 1500 UTC ENTERS THE GULF ALONG THE CENTRAL LOUISIANA COAST NEAR 29N91W AND CONTINUES ALONG 27N95W 23N96W TO TAMPICO MEXICO AND INLAND ACROSS E/CENTRAL MEXICO AS A STATIONARY FRONT. SCATTERED SHOWERS AND TSTMS ARE WITHIN 60 NM EITHER SIDE OF THE COLD FRONT. ANOTHER CONCENTRATED AREA OF SCATTERED SHOWERS AND TSTMS IS OVER THE WRN BAY OF CAMPECHE FROM 20N-23N W OF 95W. A PRE-FRONTAL SURFACE TROUGH EXTENDS INTO THE GULF FROM MOBILE BAY SWD ACROSS THE CENTRAL GULF TO THE YUCATAN PENINSULA NEAR 21N89W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE MAINLY E OF THE SURFACE TROUGH N OF 24N BETWEEN 85W-88W. CONTINUED MOIST SE SURFACE FLOW N OF A SURFACE TROUGH ACROSS CENTRAL CUBA EXTENDING INTO THE WRN CARIBBEAN IS GENERATING SCATTERED SHOWERS ACROSS THE STRAITS OF FLORIDA...SRN FLORIDA PENINSULA AND SE GULF. EXPECT THE FRONT TO CONTINUE MOVING SEWD AND WEAKEN BY MONDAY INTO TUESDAY. EARLY NEXT WEEK AS THE FRONT LIFTS NEWD...MANY OF THE GLOBAL MODELS ARE SHOWING LOW PRESSURE DEVELOPING OVER CUBA OR THE FLORIDA STRAITS... EITHER EXTRATROPICAL OR SUBTROPICAL...AND MOVING GENERALLY N. DEVELOPMENT AND TRACK IS UNCERTAIN BUT MODELS ARE IN ENOUGH AGREEMENT TO WARRANT GALE HEADLINES OVER A PORTION OF THE E AND MIDDLE WATERS FOR EARLY NEXT WEEK. CARIBBEAN SEA... A MIDDLE TO UPPER TROUGH OVER THE WRN CARIBBEAN ALONG WITH A SURFACE TROUGH EXTENDING FROM CENTRAL CUBA ALONG 79W TO NEAR 16N IS PRODUCING SCATTERED SHOWERS AND TSTMS N OF 16N BETWEEN 74W-79W. LIGHTNING DATA SHOWS THE GREATEST CONCENTRATION OF STRIKES OVER THE ADJACENT WATERS BETWEEN ERN JAMAICA AND SW HISPANIOLA. LATEST VISIBLE SATELLITE IMAGES AND GLOBAL MODEL DATA INDICATE CYCLONIC ROTATION IN THE MID-LEVEL FIELDS ALONG 79W JUST S OF CUBA. THIS FEATURE MAY BUILD CLOSER TO THE SURFACE OVER THE NEXT COUPLE OF DAYS AND DRIFT GENERALLY NWD... CONTINUING THE THREAT FOR SCATTERED SHOWERS AND TSTMS OVER THE N/CENTRAL CARIBBEAN. STRONG SWLY UPPER FLOW ON THE E SIDE OF THE AFOREMENTIONED UPPER TROUGH IS ADVECTING MOISTURE ACROSS THE SE CARIBBEAN AND LESSER ANTILLES. THIS FLOW COMBINED WITH A LOW- LEVEL TROUGH A COUPLE HUNDRED NM E OF THE AREA OVER THE TROPICAL N ATLC IS GENERATING SCATTERED SHOWERS ACROSS THE NE CARIBBEAN N OF 14N AND E OF 65W. MEANWHILE...HIGH PRESSURE CENTERED W OF BERMUDA IS MAINTAINING 15-20 KT TRADES ACROSS THE MUCH OF THE AREA E OF 78W AS CAPTURED ON AN EARLIER QSCAT PASS. THESE WINDS ARE EXPECTED TO REMAIN SIMILAR OVER THE ERN ONE-THIRD OF THE CARIBBEAN THROUGH WED AS THE HIGH WEAKENS IN PLACE OVER THE NEXT DAY OR TWO. ATLANTIC OCEAN... AN OCCLUDED 1005 MB LOW IS QUASI-STATIONARY ALONG THE NRN BORDER OF THE DISCUSSION AREA NEAR 32N52W. A COLD FRONT EXTENDS FROM 32N47W TO 27N47W CONTINUING SW TO 22N51W AND CONTINUING AS A STATIONARY FRONT TO 19N55W. FROM 19N55W THE BOUNDARY WEAKENS TO A SURFACE TROUGH AND EXTENDS SW TO 15N59W. ASSOCIATED SCATTERED SHOWERS AND ISOLATED TSTMS ARE CONFINED TO THE ERN SEMICIRCLE OF THE LOW N OF 27N BETWEEN 42W AND 49W. S OF 27N...SCATTERED SHOWERS ARE OBSERVED WITHIN 90/120 NM EITHER SIDE OF THE FRONTAL BOUNDARY. A SECONDARY WAVE OF ENERGY...ANALYZED AS A DEVELOPING COLD FRONT EXTENDS FROM 30N48W TO 27N51W TO 27N56W WITH ENHANCED CLOUDINESS AND POSSIBLE ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE OF THE FRONT. DEEP LAYER RIDGING W OF THE LOW IS PROVIDING MAINLY FAIR WEATHER ACROSS MUCH OF THE W ATLC. HOWEVER...WITH THE PROXIMITY OF THE AFOREMENTIONED SURFACE TROUGH ACROSS CENTRAL CUBA...SCATTERED SHOWERS AND TSTMS SPREAD N OF 18N BETWEEN 72W-81W OVER THE GREATER ANTILLES...BAHAMAS AND NEARBY WATERS. SEE CARIBBEAN SECTION FOR MORE DETAILS. SURFACE HIGH PRESSURE RIDGING AND MAINLY ZONAL FLOW ALOFT DOMINATE MUCH OF THE E ATLC...SUPPORTING MAINLY FAIR WEATHER. $$ HUFFMAN