000 AXNT20 KNHC 271112 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU JUN 27 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 14N44W TO 02N46W MOVING WEST NEAR 10 KT. THE WAVE COINCIDES WITH A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 03N-12N BETWEEN 39W-49W. TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN ALONG 21N71W TO 12N71W MOVING WEST NEAR 5 KT. A SURGE OF MODERATE MOISTURE IS AT THE LOWER LEVELS EAST OF THE WAVE AXIS AND WRAPS AROUND THE NORTHERN PORTION OF THE AXIS. DRIER AIR HAS UNDERCUT THIS MOISTURE TO THE NORTH SO THAT NO DEEP CONVECTION IS AROUND THE SOUTHERN PORTION OF THE WAVE. SCATTERED MODERATE CONVECTION IS S OF HAITI FROM 17N-18N BETWEEN 72W-75W...ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE NORTHERN PUERTO RICO AND LA HISPANIOLA. WEAK TROPICAL WAVE IS MOVING INTO THE WESTERN CARIBBEAN ALONG 22N82W TO 10N82W MOVING WEST NEAR 5 KT. THE WAVE HAS A WEAK MOISTURE SIGNAL WITH IT OVER THE NORTHERN PORTION AND A STRONGER SIGNAL TO THE SOUTH WITH RELATIVELY DRY AIR NEAR THE CENTRAL PORTION. SCATTERED MODERATE CONVECTION IS OVER WESTERN CUBA EXTENDING WITHIN 50 NM S OF THE COASTLINE BETWEEN 80W-84W. CLUSTERS OF MODERATE CONVECTION AND THUNDERSTORMS ARE S OF 12N WEST OF 79W IN THE SOUTHERN CARIBBEAN. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COASTAL WEST AFRICA NEAR 12N16W TO 08N23W. THE ITCZ BEGINS NEAR 08N23W AND CONTINUES ALONG 05N33W 07N42W. CLUSTERS OF MODERATE/STRONG CONVECTION ARE FROM 03N-08N BETWEEN 27W-37W AND FROM 03N-12N BETWEEN 38W-49W. ISOLATED SHOWERS/THUNDERSTORMS ARE FROM 08N-11N EAST OF 19W. ...DISCUSSION... GULF OF MEXICO... THE AZORES HIGH EXTENDS A RIDGE AXIS SW ALL THE WAY THROUGH THE GULF WHICH IS GENERATING RETURN FLOW IN THE RANGE OF 10-15 KT ACROSS THE BASIN...EXCEPT IN THE BAY OF CAMPECHE WHERE A MAXIMUM OF 25 KT IS POSSIBLE AS INDICATED BY THE LATEST ASCAT PASS. ALOFT...AN UPPER LEVEL TROUGH SPREADS OVER THE GULF WITH AN EMBEDDED CYCLONIC CIRCULATION W OF 88W. THE UPPER TROUGH IS PROVIDING MOIST SOUTHWESTERLY AND DIFFLUENT FLOW ALOFT ACROSS MOST OF THE S-SE GULF. THE UPPER CYCLONIC CIRCULATION IS SUPPORTING A SURFACE TROUGH IN THE BAY OF CAMPECHE FROM 22N90W TO 18N93W WHICH IS GENERATING ISOLATED SHOWERS S OF 23N EAST OF 95W. WITHIN A 24 HOUR PERIOD A HIGH PRESSURE WILL BUILD NEAR THE NORTHERN CENTRAL GULF...OTHERWISE LITTLE CHANGE IS EXPECTED. CARIBBEAN SEA... TWO TROPICAL WAVES ARE ACROSS THE CARIBBEAN. THE FIRST IS NEAR 83W WHERE DRY AIR IS LIMITING CONVECTION S OF 21N. SCATTERED MODERATE CONVECTION IS OVER WESTERN CUBA EXTENDING WITHIN 50 NM S OF THE COASTLINE BETWEEN 80W-84W. CLUSTERS OF MODERATE CONVECTION AND THUNDERSTORMS ARE S OF 12N WEST OF 79W IN THE SOUTHERN CARIBBEAN ASSOCIATED WITH THE MONSOON TROUGH. THE SECOND WAVE IS APPROACHING 72W. MOISTURE WITH THIS WAVE IS MAINLY TO THE NORTH AND EAST OF THE AXIS. SCATTERED MODERATE CONVECTION IS S OF HAITI FROM 17N-18N BETWEEN 72W-75W...ISOLATED SHOWERS/THUNDERSTORMS ARE OVER THE NORTHERN PUERTO RICO AND LA HISPANIOLA. ALOFT...BROAD UPPER RIDGING COVERS THE MAJORITY OF THE BASIN. TRADEWIND FLOW OF 15-20 KT IS THROUGHOUT THE AREA. BOTH WAVES ARE EXPECTED TO REMAIN WEAK/VANISH WHILE CONTINUING MOVING WEST WITHIN THE NEXT 48 HOURS. HISPANIOLA... CURRENT DRY SURFACE CONDITIONS ARE INDICATED ACROSS THE ISLAND IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS S OF HAITI FROM 17N-18N BETWEEN 72W-75W ASSOCIATED WITH THE WEAK TROPICAL WAVE MOVING OVER THE ISLAND. THE WAVE AXIS IS EXPECTED TO EXIT HAITI THURSDAY AFTERNOON BUT TRAILING MOISTURE ASSOCIATED WITH THE WAVE IS EXPECTED TO ENHANCE RAINSHOWERS THROUGHOUT THURSDAY EVENING. ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE WEST ATLC AROUND A 1021 MB HIGH NEAR 29N62W. ALOFT...AN UPPER RIDGE IS ALONG 78W...WHILE AN UPPER LOW SPINS TO THE EAST NEAR 25N63W. DIFFLUENT FLOW S OF THAT LOW IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 18N- 21N BETWEEN 62W-68W. OTHERWISE...BROAD SURFACE RIDGING DOMINATES THE REMAINDER OF THE BASIN N OF 13N EXTENDING FROM A 1038 MB HIGH NEAR 46N20W. THE METEOSAT-9 SAL TRACKING PRODUCT DEPICTS A TONGUE OF SAL DRY AIR EXTENDING FROM THE COAST OF AFRICA TO NEAR 58W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ NR