000 AXNT20 KNHC 301745 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1645 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 19N35W TO 10N36W MOVING WEST AT 15 KT. THE WAVE IS ILL-DEFINED AT THE SURFACE...BUT ALIGNS WELL WITH A 700 MB TROUGH AXIS. NO DEEP CONVECTION IS ASSOCIATED WITH THE WAVE. TROPICAL WAVE IS ALONG 21N64W TO 12N66W MOVING WEST AT 10 KT. THE WAVE LIES WITHIN A LARGE SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE CONVECTION IS FROM 12N-18N BETWEEN 59W-65W. ISOLATED MODERATE CONVECTION IS FROM 19N-22N BETWEEN 58W-63W. THIS ACTIVITY IS ALSO BEING ENHANCED BY DIFFLUENT FLOW ALOFT AROUND AN UPPER LEVEL TROUGH OVER THE EASTERN CARIBBEAN. TROPICAL WAVE IS MOVING SLOWLY THROUGH THE WESTERN CARIBBEAN ALONG 20N84W TO 12N83W MOVING WEST AT 5-10 KT. THE WAVE LIES WITHIN A BROAD AREA OF ENHANCED MOISTURE OVER MUCH OF THE WESTERN CARIBBEAN. SCATTERED MODERATE/STRONG CONVECTION IS EAST OF THE AXIS FROM 16N-20N BETWEEN 82W-84W. SIMILAR ACTIVITY IS FROM 9N-15N BETWEEN 77W-80W. SCATTERED MODERATE CONVECTION IS ALSO FROM 15N-23N BETWEEN 79W-83W. A SHORTWAVE UPPER TROUGH EXTENDING FROM EASTERN CUBA TO NEAR 16N80W MAY BE ENHANCING SOME OF THIS CONVECTION. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF MAURITANIA NEAR 19N16 TO 12N19W 10N23W. THE ITCZ BEGINS NEAR 10N23W AND CONTINUES ALONG 8N33W 4N41W EQ52W. ISOLATED MODERATE CONVECTION IS FROM 9N-13N BETWEEN 17W-23W. SIMILAR ACTIVITY IS WITHIN 140 NM SOUTH OF THE AXIS BETWEEN 25W-32W. SCATTERED MODERATE CONVECTION IS WITHIN 160 NM SOUTH OF THE AXIS BETWEEN 35W-42W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL TROUGH CONTINUES TO DIG SOUTHWARD INTO THE GULF OF MEXICO WITH AXIS EXTENDING FROM EASTERN LOUISIANA NEAR 29N90W TO THE SW GULF NEAR 20N93W. THE UPPER TROUGH SUPPORTS A FRONTAL BOUNDARY THAT STILL BORDERS THE NW GULF COAST. A PRE-FRONTAL SURFACE TROUGH IS OUT AHEAD OF THE FRONT ALONG 31N85W 28N90W 28N95W...AS OF 1500 UTC. RADAR IMAGERY AND LIGHTNING DATA INDICATE SCATTERED SHOWERS/THUNDERSTORMS ARE THROUGHOUT THE NE GULF NORTH OF 26N TO THE SURFACE TROUGH...EAST OF 94W. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO IN THE SE GULF. ONLY THE SW GULF REMAINS RELATIVELY CLEAR. MAINLY WEST TO SOUTHWEST WINDS ARE IMPACTING THE GULF INCREASING FROM 5-10 KT IN THE SOUTHERN GULF TO 15-20 KT NEAR THE SURFACE TROUGH. THE FRONTAL BOUNDARY/SURFACE TROUGH WILL REMAIN ACROSS THE NORTHERN GULF WITH MOIST CONDITIONS REMAINING OVER MUCH OF THE EASTERN GULF. CARIBBEAN SEA... A TROPICAL WAVE CONTINUES TO MOVE SLOWLY THROUGH THE WESTERN CARIBBEAN ALONG 84W. 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...WHICH IS LIKELY ENHANCING SOME OF THE ACTIVITY NEAR THE WAVE. SOUTH OF THE WAVE...THE MONSOON TROUGH EXTENDS FROM COSTA RICA TO NORTHERN COLOMBIA. WEAK UPPER RIDGING COVERS THE CENTRAL CARIBBEAN ALONG WITH DRY AIR ALOFT...WHICH IS KEEPING THIS PORTION OF THE BASIN RATHER CLEAR. THE EASTERN CARIBBEAN IS IMPACTED BY A SECOND TROPICAL WAVE NEAR 65W. CONVECTION NEAR THE WAVE IS BEING SHEARED TO THE EAST DUE TO SOUTHWESTERLY FLOW ALOFT AROUND AN UPPER TROUGH ALONG 68W. 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 SOUTH OF 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... HISPANIOLA IS FAIRLY DRY AT THIS TIME WITH NO NOTABLE SHOWERS OR THUNDERSTORMS AT THIS TIME. AS HEATING CONTINUES THROUGHOUT THE DAY SHOWER ACTIVITY WILL LIKELY INCREASE. MOISTURE AHEAD OF THE TROPICAL WAVE IN THE EASTERN CARIBBEAN HAS ALSO ALMOST REACHED THE INLAND...WHICH WILL INCREASE THE CHANCE OF RAIN. 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 75W-80W ASSOCIATED WITH MOIST AND DIFFLUENT FLOW ALOFT BETWEEN AN UPPER TROUGH OVER THE GULF OF MEXICO AND AN UPPER LEVEL RIDGE TO THE EAST NEAR 34N74W. A BROAD UPPER LOW IS CENTERED NEAR 26N63W. THE UPPER LOW SUPPORTS A WEAK SURFACE TROUGH ALONG 37N55W TO 28N54W. A FEW ISOLATED SHOWERS ARE WITHIN 75 NM EITHER SIDE OF THE AXIS. A STRONGER 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 $$ WALTON