000 AXNT20 KNHC 041749 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE JUN 04 2013 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...SPECIAL FEATURES... A SURFACE TROUGH IS IMPACTING THE GULF OF MEXICO ALONG 29N88W TO 19N90W. THE CYCLONIC FLOW IS MOST CONCENTRATED NEAR 25N89W...BUT NO CLEAR DEFINED LOW CENTER HAS FORMED YET. CONVECTION IS LOCATED ONLY EAST OF THE TROUGH...WHICH IS BEING ENHANCED BY AN UPPER LEVEL TROUGH 87W. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS IN THE NW CARIBBEAN FROM 17N-23N BETWEEN 83W-87W. ISOLATED MODERATE CONVECTION IS FROM 23N-28N BETWEEN 80W-87W. THIS SYSTEM HAS A MEDIUM CHANCE OF DEVELOPING INTO A TROPICAL CYCLONE OVER THE NEXT 48 HOURS AS IT SLOWLY MOVES NORTHWARD OR NORTHEASTWARD. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 17N35W TO 9N37W MOVING WEST NEAR 10 KT. THE WAVE LIES ON THE WEST SIDE OF A SURGE OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS ALSO A CLEARING IN THE AREA OF AFRICAN DUST THAT IS NORTH...WEST...AND NOW EAST OF THE WAVE. THE WAVE ALSO COINCIDES WITH A 700 MB TROUGH AXIS. SCATTERED MODERATE CONVECTION IS FROM 8N-11N BETWEEN 36W-40W. TROPICAL WAVE IS ALONG 21N64W 12N65W MOVING WEST-NORTHWEST NEAR 15 KT. THE WAVE LIES WITHIN A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. IT ALSO IS JUST WEST OF A LARGE AREA OF DUST THAT EXTENDS AROUND THE EASTERNMOST WAVE AND CONTINUES TO ABOUT 60W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 17N-23N BETWEEN 61W-67W. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF GUINEA-BISSAU NEAR 12N15W TO 8N19W. THE ITCZ BEGINS NEAR 8N19W AND CONTINUES TO 5N33W AND PICKS UP IN THE WEST SIDE OF A TROPICAL WAVE ALONG 8N40W 5N50W. ISOLATED MODERATE CONVECTION IS FROM 3N-9N BETWEEN 13W-18W...FROM 4N-9N BETWEEN 22W-28W. SCATTERED MODERATE CONVECTION IS FROM 5N-8N BETWEEN 40W-44W. ...DISCUSSION... GULF OF MEXICO... SURFACE TROUGHING CONTINUES TO DOMINATE THE WEATHER PATTERN ACROSS THE GULF OF MEXICO WITH AXIS FROM NEAR 29N88W TO 19N90W. DEEP TROPICAL MOISTURE IS BEING DRAWN ACROSS THE EASTERN GULF SUPPORTING WIDESPREAD SHOWERS AND ISOLATED THUNDERSTORMS SOUTH OF 28N EAST OF 88W. SEE SPECIAL FEATURES FOR MORE DETAILS. AS THIS MOISTURE REMAINS OVER THE AREA FOR THE NEXT SEVERAL DAYS...PORTIONS OF SOUTH AND CENTRAL FLORIDA COULD RECEIVE LARGE AMOUNTS OF RAIN. WEST OF THE TROUGH AXIS...FAIRLY DRY AIR AND CLEAR SKIES ARE PRESENT. DRY AIR ALOFT IS SINKING INTO THIS AREA AROUND AN UPPER LEVEL TROUGH ALONG 87W. THE UPPER TROUGH IS ALSO PROVIDING A DIFFLUENT REGION OVER THE EASTERN GULF HELPING SUPPORT THE LARGE AREA OF SHOWER AND THUNDERSTORMS ACTIVITY. LIGHT CYCLONIC WIND FLOW IS AROUND THE SURFACE TROUGH...EXCEPT ON THE EASTERN SIDE OF THE TROUGH WHERE SE FLOW OF 15-25 KT IS PRESENT. BROAD SURFACE TROUGHING WILL REMAIN OVER THE GULF THROUGHOUT THE WEEK WITH DEEP TROPICAL MOISTURE IMPACTING MUCH OF THE EASTERN GULF. A SURFACE LOW MAY FORM ALONG THE TROUGH AXIS. CARIBBEAN SEA... ABUNDANT DEEP LAYER MOISTURE IS THROUGHOUT THE NORTHWESTERN CARIBBEAN EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SOUTHEAST FLOW CONTINUES TO DRAW TROPICAL MOISTURE INTO THIS AREA AND INTO THE SE GULF. CURRENTLY...A LARGE BURST OF STRONG SHOWERS/SCATTERED THUNDERSTORMS IS FROM 16N-23N BETWEEN 83W-87W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE ALSO FROM 21N-23N BETWEEN 80W-83W ACROSS WESTERN CUBA. THE REMAINDER OF THE CARIBBEAN IS FAIRLY DRY IN COMPARISON EXCEPT FOR SOME ACTIVITY NEAR A TROPICAL WAVE. THE WAVE IS ALONG 65W AND SUPPORTS SCATTERED SHOWERS/THUNDERSTORMS FROM 17N-19N BETWEEN 63W- 67W...INCLUDING AREAS OF PUERTO RICO. ONLY A FEW ISOLATED SHOWERS ARE EMBEDDED ELSEWHERE WITHIN TRADEWIND FLOW OF 20-25 KT. VISIBLE SATELLITE IMAGERY ALONG WITH SURFACE OBSERVATIONS INDICATE AN AREA OF SAHARAN DUST HAS REACHED THE EASTERN CARIBBEAN EAST OF THE TROPICAL WAVE...WHICH IS LIMITING THE EFFECTS OF THE MOISTURE NEAR THE WAVE. ALOFT...AN UPPER LEVEL RIDGE COVERS THE WESTERN HALF OF THE BASIN WITH AXIS ALONG 80W. THE BASE OF AN UPPER TROUGH EXTENDS TO THE NE CARIBBEAN...WHICH IS PROVIDING DIFFLUENT FLOW ALOFT NEAR THE TROPICAL WAVE. THE NW CARIBBEAN WILL REMAIN UNDER VERY MOIST CONDITIONS FOR THE NEXT COUPLE OF DAYS. THE TROPICAL WAVE IN THE EASTERN CARIBBEAN WILL CONTINUE TO DRIFT WEST-NORTHWEST FOR THE NEXT 24 HOURS BEFORE DISSIPATING. MOISTURE ASSOCIATED WITH THE WAVE WILL STILL REMAIN OVER THE EASTERN/CENTRAL CARIBBEAN. HISPANIOLA... HISPANIOLA IS FAIRLY DRY FOR THE TIME BEING WITH ONLY A FEW ISOLATED SHOWERS/THUNDERSTORMS OVER THE EASTERN HALF OF THE ISLAND. AFTERNOON ACTIVITY WILL LIKELY INCREASE AS THE DAY CONTINUES. A TROPICAL WAVE IS JUST EAST OF PUERTO RICO WITH AN INCREASED MOISTURE FIELD THAT HAS REACHED EASTERN HISPANIOLA. AN UPPER TROUGH IS ENHANCING CONVECTION NEAR THE NORTHERN EXTENT OF THE WAVE...WHICH IS STILL EAST OF THE ISLAND. AS THE WAVE MOVES WEST OVER THE NEXT 24 HOURS IT COULD INCREASE THE AMOUNT OF PRECIPITATION OVER HISPANIOLA. HOWEVER...A LARGE AREA OF DRY SAHARAN DUST IS IMMEDIATELY EAST OF THE WAVE AND WILL LIKELY REACH THE HISPANIOLA BY 48 HOURS. ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE WEST AND CENTRAL ATLC AROUND A 1029 MB HIGH NEAR 34N50W. MOISTURE ASSOCIATED WITH THE BROAD SURFACE TROUGH IN THE GULF OF MEXICO IS FILTERING OVER INTO THE FAR WEST ATLC ISOLATED SHOWERS AND POSSIBLE THUNDERSTORMS WEST OF 72W. A TROPICAL WAVE IN THE EASTERN CARIBBEAN IS ALSO SUPPORTING AN AREA OF SHOWERS/THUNDERSTORMS FROM 19N-23N BETWEEN 61W-68W. THIS ACTIVITY IS BEING ENHANCED BY AN UPPER LEVEL TROUGH ALONG 30N57W TO 19N69W. UPPER LEVEL RIDGING ALONG 80W COVERS THE FAR WEST ATLC. BROAD UPPER RIDGING ALSO COVERS THE CENTRAL ATLC ALONG 35W SUPPORTING THE SURFACE RIDGE. AN UPPER TROUGH IS ALONG 32N20W TO 22N25W...BUT IS NOT CAUSING ANY ACTIVE WEATHER IN THE DISCUSSION AREA. SURFACE RIDGING ALSO DOMINATES THE EASTERN ATLC EXTENDING FROM A 1022 MB HIGH NEAR 37N21W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CENTERED OVER AFRICA NEAR 18N4W. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW A LARGE AREA OF SAHARAN DUST EXTENDING AROUND THE TROPICAL WAVE IN THE EASTERN ATLC AND CONTINUING TO NEAR 64W IN THE EASTERN CARIBBEAN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON