000 AXNT20 KNHC 030006 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE JUL 02 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2345 UTC. ...TROPICAL WAVES... A NEW TROPICAL WAVE HAS COME OFF THE WEST AFRICAN COAST. ITS AXIS IS EMBEDDED WITHIN THE MONSOON TROUGH AND IS CURRENTLY ALONG 16N18W TO 06N17W. TOTAL PRECIPITABLE WATER IMAGERY SHOW HIGH MOISTURE WITHIN ITS ENVIRONMENT AT THE LOWER LEVELS AND WATER VAPOR IMAGERY MODERATE MOISTURE AT THE MIDDLE LEVELS. HOWEVER...NO DEEP CONVECTION IS CURRENTLY ASSOCIATED WITH THE WAVE AT THIS TIME. TROPICAL WAVE IS ALONG 19N31W TO 12N32W MOVING WEST NEAR 5 KT. SAL DRY AIR SPREADS OVER THE WAVE ENVIRONMENT AS INDICATED IN THE METEOSAT-9 SAL TRACKING PRODUCT WHICH IS HINDERING ANY CONVECTIVE ACTIVITY. TROPICAL WAVE MOVING TOWARDS THE EASTERN CARIBBEAN...WITH AXIS ALONG 19N55W TO 11N55W. IT IS MOVING NEAR 15 KT WITHIN A LOWER LEVELS DRY ENVIRONMENT. THE METEOSAT-9 SAL TRACKING PRODUCT SHOW THIS WAVE IS EMBEDDED WITHIN SAL DRY AIR WHICH IS INHIBITING CONVECTION AT THIS TIME. TROPICAL WAVE AXIS OVER THE WESTERN CARIBBEAN ALONG 23N82W TO 17N82W MOVING NEAR 20 KT. EVEN THAT THIS WAVE IS ENHANCING NUMEROUS MODERATE/ISOLATED STRONG CONVECTION N OF 18N WEST OF 78W...ITS STRUCTURE HAS WEAKENED WITH ITS SOUTHERN PART BEING TRANSITIONED TO A SURFACE TROUGH ALONG THE COASTS OF HONDURAS...NICARAGUA AND COASTA RICA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE WEST AFRICAN COAST NEAR 11N15W TO 09N21W. THE ITCZ BEGINS NEAR 09N21W AND CONTINUES ALONG 10N30W 07N40W 02N50W. ISOLATED MODERATE CONVECTION IS WITHIN 250 NM S OF THE ITCZ AXIS AND WITHIN 120 NM N OF THE AXIS BETWEEN 33W-51W. ...DISCUSSION... GULF OF MEXICO... A DEEP AND BROAD UPPER LEVEL TROUGH EXTENDING AN AXIS ACROSS CENTRAL U.S. INTO THE GULF IS SUPPORTING A WEAK STATIONARY FRONT THAT ENTERS THE BASIN BY SOUTHERN ALABAMA NEAR 30N88W TO 27N89W WHERE IT TRANSITIONS TO A SURFACE TROUGH TO 24N93W. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 40 NM EITHER SIDE OF THE FRONTAL BOUNDARY AND EXTENDS TO THE SW GULF FROM 21N-24N BETWEEN 93W-97W. ADVECTION OF LOWER AND MIDDLE LEVELS MOISTURE FROM THE WEST CARIBBEAN TO THE EASTERN GULF COMBINED WITH UPPER LEVEL DIFFLUENCE CONTINUE ENHANCING SCATTERED MODERATE CONVECTION AND THUNDERSTORMS ACROSS FLORIDA AS WELL AS S OF 26N EAST OF 83W...INCLUDING THE STRAITS OF FLORIDA. SIMILAR CONVECTION IS S OF 23N BETWEEN THE YUCATAN CHANNEL AND THE YUCATAN PENINSULA. WINDS ARE FAIRLY LIGHT ACROSS MUCH OF THE AREA WITH STRONGER SOUTHERLY WINDS ACROSS THE SE GULF REACHING UP TO 15 KT. HIGH MOISTURE ADVECTION TO THE GULF WILL CONTINUE WITHIN THE NEXT 48 HOURS AS WELL AS A DIFFLUENT UPPER LEVEL PATTERN WHICH WILL CONTINUE TO ENHANCE PRECIPITATION AND THUNDERSTORMS. THESE WILL EXTENDS TO THE CENTRAL GULF AS THE UPPER LEVEL RIDGE OVER WESTERN CARIBBEAN AND PORTIONS OF CUBA DRIFTS WESTWARD. BROAD SURFACE TROUGHING WILL DOMINATES MUCH OF THE GULF AND A LOW MAY FORM IN THE NE GULF. CARIBBEAN SEA... A TROPICAL WAVE WITH AXIS CURRENTLY OVER WESTERN CUBA AND UPPER LEVEL DIVERGENCE IS ENHANCING NUMEROUS MODERATE/ISOLATED STRONG CONVECTION AND THUNDERSTORMS ACROSS CUBA AND FROM 17N-22N BETWEEN 78W-85W. THE SOUTHERN PORTION OF THIS TROPICAL WAVE TRANSITIONED TO A SURFACE TROUGH THAT IS ALONG THE COASTLINES OF HONDURAS AND NICARAGUA. ISOLATED MODERATE CONVECTION/THUNDERSTORMS ARE WITHIN 130 NM N OF THE HONDURAS COASTLINE BETWEEN 82W-85W ASSOCIATED WITH THE NORTHERN PART OF THIS TROUGH. SIMILAR CONVECTION IS OCCURRING IN THE SOUTHERN CARIBBEAN WITHIN 80 NM N OF THE MONSOON TROUGH AXIS BETWEEN 79W- 81W. UPPER LEVEL DIFFLUENCE FROM THE RIDGE OVER THE WEST CARIBBEAN AND A CYCLONIC CIRCULATION OVER THE WEST ATLC IS ENHANCING SHOWERS AND THUNDERSTORMS ACROSS LA HISPANIOLA. SIMILAR CONVECTION IS OCCURRING ACROSS THE MONA PASSAGE. OTHERWISE...TRADEWINDS UP TO 20 KT ABOUND ACROSS THE BASIN WITH THE MAXIMUM WINDS BEING IN THE CENTRAL CARIBBEAN DUE TO A TIGHTER PRESSURE GRADIENT. A NEW TROPICAL WAVE WILL MOVE INTO THE EASTERN CARIBBEAN WEDNESDAY MORNING. HISPANIOLA... UPPER LEVEL DIFFLUENCE FROM THE RIDGE OVER THE WEST CARIBBEAN AND A CYCLONIC CIRCULATION OVER THE WEST ATLC IS ENHANCING SHOWERS AND THUNDERSTORMS ACROSS LA HISPANIOLA. A COMBINATION OF A PERSISTENT UPPER LEVEL SYNOPTIC PATTERN AND PATCHES OF LOW LEVEL MOISTURE MOVING ACROSS THE ISLAND WILL CONTINUE TO ENHANCE RAINSHOWERS/THUNDERSTORMS WITHIN THE NEXT 48 HOURS. ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE WEST AND CENTRAL ATLC AROUND A 1029 MB HIGH NEAR 35N61W. SCATTERED SHOWERS/THUNDERSTORMS ARE OFF THE COAST OF FLORIDA WEST OF 78W ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE GULF OF MEXICO. A WEAK SURFACE IS ALONG 30N64W TO 27N62W WITH NO CONVECTION ASSOCIATED WITH IT. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY BROAD SURFACE RIDGING EXTENDING FROM A PAIR OF 1029 MB AZORES HIGHS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR