000 AXNT20 KNHC 010002 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN JUN 30 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... TROPICAL WAVE IS ALONG 20N37W TO 10N38W MOVING WEST AT 15 KT. THE WAVE IS ILL-DEFINED AT THE SURFACE PER A 2022 UTC ASCAT PASS. THE WAVE IS WELL DEFINED AT 700 MB AND IS ALIGNED WITH A TROUGH AXIS AT THAT LEVEL. NO DEEP CONVECTION IS ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 21N65W TO 12N67W MOVING WEST AT 10 KT. THE WAVE LIES WITHIN A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION REMAINS AT THE FAR NORTHERN END OF THE WAVE AT THE BASE OF AN UPPER LEVEL TROUGH...GENERALLY FROM 19N-21N BETWEEN 62W-65W. TROPICAL WAVE IS MOVING SLOWLY THROUGH THE WESTERN CARIBBEAN ALONG 20N85W TO THE COAST OF HONDURAS ALONG 85W...MOVING WEST AT 5-10 KT. THE WAVE LIES WITHIN A BROAD AREA OF ENHANCED MOISTURE OVER MUCH OF THE WESTERN CARIBBEAN. SCATTERED STRONG CONVECTION IS EAST OF THE AXIS FROM 20N EXTENDING NORTHWARD OVER WESTERN CUBA AND THE STRAITS OF FLORIDA BETWEEN 82W-85W. SCATTERED MODERATE CONVECTION IS ALSO FROM 13N-19N BETWEEN 80W-84W. A SHARP UPPER TROUGH OVER THE CENTRAL GULF OF MEXICO AND ASSOCIATED STRONG DIFFLUENT FLOW ALOFT IS ENHANCING THIS CONVECTION AND ADVECTING THE MOISTURE NORTHWARD. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF MAURITANIA NEAR 15N17W TO 11N20W TO 10N22W. THE ITCZ BEGINS NEAR 10N22W AND CONTINUES ALONG 9N30W 4N40W TO THE COAST OF SOUTH AMERICA NEAR 2N51W. ISOLATED MODERATE CONVECTION IS FROM 3N-6N BETWEEN 37W- 41W. NO SIGNIFICANT CONVECTION ELSEWHERE ALONG THE AXIS. ...DISCUSSION... GULF OF MEXICO... A VERY SHARP UPPER LEVEL TROUGH FOR LATE JUNE CONTINUES TO DIG SOUTHWARD INTO THE CENTRAL GULF OF MEXICO WITH AXIS EXTENDING FROM EASTERN LOUISIANA NEAR 29N90W TO THE SW GULF NEAR 19N91W. THE UPPER TROUGH SUPPORTS A COLD FRONT THAT AS OF 2100 UTC EXTENDS FROM NEAR PENSACOLA FLORIDA THROUGH 28.5N90W TO 28N93W. A PRE-FRONTAL SURFACE TROUGH EXTENDS FROM NEAR APALACHICOLA FLORIDA TO 26N91W. COMPOSITE RADAR IMAGERY AND LIGHTNING DATA INDICATE SCATTERED SHOWERS/THUNDERSTORMS ARE OCCURRING THROUGHOUT THE GULF GENERALLY E OF 90W AND THE PRE-FRONTAL SURFACE TROUGH. THE STRONGEST ACTIVITY IS OVER WESTERN CUBA...THE FLORIDA STRAITS AND STREAMING NORTHWARD OVER THE FLORIDA PENINSULA. TOTAL PRECIPITABLE WATER IMAGERY AND INDICATED THAT DEEP LAYERED TROPICAL MOISTURE IS BEING ADVECTED FROM THE CARIBBEAN NORTHWARD ACROSS FLORIDA AND ALONG THE EAST COAST OF THE U.S. MOST OF THE GULF W OF 90W IS DOMINATED BY DRY AIR ALOFT WITH POCKETS OF MID TO UPPER LEVEL MOISTURE NOTED. SOUTH TO SOUTHWEST WINDS ARE IMPACTING THE GULF INCREASING FROM 5-10 KT IN THE SOUTHERN GULF TO 15-20 KT NEAR THE SURFACE TROUGH. WINDS SHIFT TO THE NORTHWEST TO THE WEST OF THE COLD FRONT AND SURFACE TROUGH. THE FRONTAL BOUNDARY/SURFACE TROUGH WILL REMAIN ACROSS THE NORTHERN GULF WITH MOIST CONDITIONS REMAINING OVER MUCH OF THE EASTERN GULF OVER THE NEXT SEVERAL DAYS. CARIBBEAN SEA... A TROPICAL WAVE CONTINUES TO MOVE SLOWLY THROUGH THE WESTERN CARIBBEAN ALONG 85W. IT IS HELPING ENHANCE SCATTERED SHOWERS/THUNDERSTORMS OVER WESTERN CUBA AND UP TO 300 NM EAST OF THE AXIS. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. AN UPPER TROUGH EXTENDS FROM EASTERN CUBA TO NEAR 16N80W. THE NORTHERN PART OF THE TROPICAL WAVE AND ASSOCIATED CONVECTION IS NOW BEING ENHANCED BY A VERY SHARP UPPER LEVEL TROUGH IN THE CENTRAL GULF OF MEXICO. SOUTH OF THE WAVE...THE MONSOON TROUGH EXTENDS FROM NORTHERN COLOMBIA TO THE BORDER OF COSTA RICA AND NICARAGUA. WEAK UPPER RIDGING COVERS THE CENTRAL CARIBBEAN WITH ONLY HIGH LEVEL MOISTURE NOTED. DRY AIR AT THE REMAINING LEVELS IS KEEPING THIS PORTION OF THE BASIN RATHER CLEAR. THE EASTERN CARIBBEAN IS IMPACTED BY A SECOND TROPICAL WAVE NEAR 65W/66W. CONVECTION NEAR THE WAVE IS BEING SHEARED TO THE EAST DUE TO SOUTHWESTERLY FLOW ALOFT AROUND AN UPPER TROUGH AND ELONGATED UPPER LOW NEAR 26N64W. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE EAST OF THE WAVE THROUGH THE LESSER ANTILLES. A FEW CLUSTERS OF SHOWERS/THUNDERSTORMS ARE WEST OF THE WAVE OVER WESTERN PUERTO RICO AND THE DOMINICAN REPUBLIC. EXCEPT FOR THE SLIGHT CYCLONIC FLOW NEAR THE TWO WAVES...TRADEWIND FLOW OF 15-20 KT DOMINATES ELSEWHERE. BOTH WAVES ARE EXPECTED TO MOVE WEST OVER THE NEXT SEVERAL DAYS. WIDESPREAD MOISTURE WILL REMAIN OVER THE FAR WESTERN GULF AND CENTRAL AMERICA. HISPANIOLA... DIURNALLY ENHANCED CONVECTION IS OCCURRING OVER HISPANIOLA WITH LIGHTNING DATA INDICATING FREQUENT CLOUD TO GROUND STRIKES. MOISTURE AHEAD OF THE TROPICAL WAVE IN THE EASTERN CARIBBEAN AND PRECIPITABLE WATER MAXIMA IN THE GLOBAL MODELS SHOULD REACH THE ISLAND OVERNIGHT INTO MON...INCREASING THE CHANCES OF MORE WIDESPREAD THUNDERSTORM ACTIVITY. MOISTURE DECREASES TUE AND WED AS THE TROPICAL WAVE MOVES W OF THE AREA. ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE WEST AND CENTRAL ATLC AROUND A 1031 MB HIGH NEAR 41N46W. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS MUCH OF THE NW BAHAMAS NORTH OF 26N BETWEEN 77W-80W ASSOCIATED WITH MOIST AND DIFFLUENT FLOW ALOFT BETWEEN AN UPPER TROUGH OVER THE GULF OF MEXICO AND A NARROW UPPER LEVEL RIDGE TO THE EAST ALONG 74W. A BROAD UPPER LOW IS CENTERED NEAR 26N64W. THE UPPER LOW IS ENHANCING SHOWER ACTIVITY ASSOCIATED WITH A WEAK SURFACE TROUGH ALONG 36N56W TO 28N54W. A FEW ISOLATED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE TROUGH. A LARGER UPPER LOW IS TO THE EAST NEAR 33N47W...BUT IS NOT CAUSING ANY ACTIVE WEATHER. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY BROAD SURFACE RIDGING EXTENDING FROM A 1032 MB AZORES HIGH. BROAD UPPER RIDGING SUPPORTS THE SURFACE RIDGE EXTENDS FROM THE AZORES TO NEAR 19N32W 11N57W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ COBB