000 AXNT20 KNHC 212351 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI JUN 21 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 2245 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS FROM 15N31W TO 5N31W MOVING WEST AT 20-25 KT. THE WAVE COINCIDES WITH A SMALL SURGE IN DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. THERE IS ALSO A CLEARING IN THE SAHARAN AIR LAYER IMMEDIATELY AROUND THE WAVE. SCATTERED MODERATE IS FROM 2N-8N BETWEEN 29W-33W. TROPICAL WAVE IS FROM 17N45W TO 8N46W MOVING WEST NEAR 15 KT. THE WAVE LIES ON THE WESTERN SIDE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. NO DEEP CONVECTION IS ASSOCIATED WITH THE WAVE. TROPICAL WAVE OVER THE CARIBBEAN HAS BEEN SPLIT WITH THE SOUTHERN PORTION EXTENDING FROM 21N79W TO 11N80W MOVING WEST NEAR 15 KT. THE NORTHERN PORTION IS BEING ANALYZED AS A SURFACE TROUGH AND WILL BE DISCUSSION IN THE ATLC SECTION. THE WAVE ALIGNS WITH AN AREA OF MAXIMUM MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/STRONG CONVECTION IS ACROSS SOUTHERN CUBA...AND IS ALONG THE WAVE NEAR 18N. SIMILAR ACTIVITY IS FROM 10N-15N BETWEEN 81W-84W IMPACTING EASTERN NICARAGUA. MORE ACTIVITY IS TO THE SOUTH ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS ALONG 10N. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 13N17W TO 9N20W. THE ITCZ BEGINS NEAR 9N20W AND CONTINUES ALONG 6N38W 6N54W. NO DEEP CONVECTION IS NOTED BESIDES NEAR TROPICAL WAVES. ...DISCUSSION... THE GULF OF MEXICO... MOISTURE STILL REMAINS OVER THE FAR SW GULF ASSOCIATED WITH THE REMNANTS OF BARRY THAT HAVE DISSIPATED. ISOLATED SHOWERS AND THUNDERSTORMS ARE SOUTH OF 24N WEST OF 95W. WEAK HIGH PRESSURE IS OVER THE MAJORITY OF THE BASIN CENTERED AROUND A 1020 MB HIGH NEAR 29N91W...AS OF 2100 UTC. A WEAK FRONTAL BOUNDARY STILL IMPACTS THE NE CORNER WITH A WARM FRONT EXTENDING THROUGH THE FLORIDA PANHANDLE ALONG 31N88W TO 29N82W BECOMING STATIONARY TO THE EAST...ALSO AS OF 2100 UTC. ISOLATED SHOWERS/THUNDERSTORMS ARE NORTH OF 27N EAST OF 92W WITH MORE SCATTERED ACTIVITY OVER FLORIDA. ALOFT...UPPER LEVEL RIDGING COVERS THE WESTERN GULF WHILE AN UPPER TROUGH DIPS SOUTH OVER THE NE GULF SUPPORTING THE FRONTAL BOUNDARY. A SECOND INVERTED UPPER TROUGH COVER THE SE GULF. WATER VAPOR IMAGERY ALSO INDICATES DRY AIR IS ACROSS THE CENTRAL PORTIONS OF THE AREA...WHICH IS HELPING SUPPORT FAIR WEATHER. THE FRONT IS EXPECTED TO CONTINUE LIFTING NORTH WITH MOISTURE REMAINING OVER THE NE CORNER OF THE BASIN AND WILL LIKELY CONTINUE TO PRODUCE SHOWERS/THUNDERSTORMS. A SURFACE TROUGH IN THE ATLC WILL DRIFT WEST TOWARDS FLORIDA AND LIKELY BRING MORE MOISTURE TO THE STATE. THE CARIBBEAN SEA... A TROPICAL WAVE NEAR 80W IS SUPPORTING SHOWERS/THUNDERSTORMS OVER SOUTHERN CUBA...AND ACROSS THE SW CARIBBEAN. SEE TROPICAL WAVE SECTION ABOVE FOR MORE DETAILS. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO SOUTH OF 10N COVERING COSTA RICA AND PANAMA ASSOCIATED WITH BOTH THE TROPICAL WAVE AND THE MONSOON TROUGH THAT EXTENDS ALONG 10N TO NORTHERN COLOMBIA. ALOFT...AN UPPER LEVEL TROUGH EXTENDS FROM THE WINDWARD PASSAGE TO NORTHERN COLOMBIA DRAWING DRY AIR OVER A GOOD PORTION OF THE WESTERN AND CENTRAL CARIBBEAN...WHILE MOIST SOUTHWESTERLY FLOW ALOFT COVERS THE EASTERN SIDE. ISOLATED SHOWERS ARE MOVING THROUGH THE LEEWARD ISLANDS IN AN AREA OF SLIGHTLY INCREASED MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. TRADEWIND FLOW OF 20-25 KT IS PRESENT THROUGHOUT MUCH OF THE BASIN. THE WAVE IS EXPECTED TO CONTINUE MOVING WEST AND WILL IMPACT CENTRAL AMERICA. LITTLE CHANGE IS EXPECTED ELSEWHERE. HISPANIOLA... ONLY A FEW WIDELY ISOLATED SHOWERS/THUNDERSTORMS ARE OVER HAITI FROM 18N-19N BETWEEN 71W-73W. THIS REDUCTION IN ACTIVITY IS DUE TO A DRY AND STABLE AIRMASS SITUATED OVER THE CENTRAL CARIBBEAN. THERE IS AN AREA OF INCREASED MOISTURE TO THE EAST CURRENTLY OVER THE NE CARIBBEAN...WHICH IS EXPECTED TO SHIFT WEST AND WILL LIKELY BRING MORE ACTIVITY TO THE ISLANDS OVER THE WEEKEND. THE ATLANTIC OCEAN... A WEAK FRONTAL BOUNDARY OVER THE NE GULF COAST CONTINUES INTO THE ATLC TO NEAR 32N78W. ISOLATED SHOWERS ARE NEAR THE AXIS. A SURFACE TROUGH IS THE SOUTH ORIGINATING FROM A TROPICAL WAVE IN THE CARIBBEAN. THE WAVE HAS SPLIT AS THE SOUTHERN PORTION CONTINUES WESTWARD WHILE THIS NORTHERN PORTION WAS MOVING MORE NW. THE TROUGH IS CURRENTLY ALONG 28N71W TO 22N74W PRODUCING SCATTERED SHOWERS/THUNDERSTORMS UP TO 140 NM TO THE WEST. THE TROUGH IS EXPECTED TO CONTINUE MOVING NW TOWARDS FLORIDA...AND WILL LIKELY INCREASE SHOWER/THUNDERSTORM ACTIVITY OVER THE WEEKEND ACROSS THE STATE. ALOFT...AN UPPER LEVEL RIDGE IS ACROSS THE FAR WESTERN ATLC...WHILE AN UPPER LEVEL LOW SPINS NORTH OF HISPANIOLA NEAR 21N72W. THE REMAINDER OF THE BASIN IS DOMINATED BY BROAD SURFACE RIDGING ANCHORED BY A 1034 MB AZORES HIGH. BROAD UPPER RIDGING OVER THE NE ATLC SUPPORTS THE SURFACE RIDGE...AS DOES BROAD UPPER RIDGING OVER THE TROPICAL ATLC. TWO UPPER LOWS ARE IN THE MIDDLE NEAR 30N46W AND 25N27W. NEITHER IS CAUSING ANY ACTIVE WEATHER IN THE BASIN. A STABLE DRY AIRMASS COVERS MUCH OF THE EASTERN ATLC INDICATED BY THE LARGE AREA OF DUST THAT EXTENDS FROM THE COAST OF AFRICA AROUND THE TROPICAL WAVES TO NEAR 49W. 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