000 AXNT20 KNHC 291109 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU MAY 29 2014 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 1045 UTC. ...TROPICAL WAVES... TROPICAL WAVE IS OVER THE EASTERN TROPICAL ATLC WITH AXIS ALONG 32W S OF 9N MOVING W AT 15-20 KT. THE WAVE IS ON THE WESTERN PERIPHERY OF A SAHARAN DUST OUTBREAK NOTED ON METEOSAT PSEUDO NATURAL COLOR IMAGERY. THE SOUTHERN PORTION OF THE WAVE IS EMBEDDED WITHIN THE ITCZ AXIS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 120 NM E AND 60 NM W OF THE WAVE FROM 04N-05N. A TROPICAL WAVE IS ALONG 45W S OF 08N MOVING NEAR 15 KT. DURING THE LAST 24 HOURS. AN INVERTED-V CLOUD PATTERN IS NOTED ON IR SHORTWAVE IMAGERY ANIMATION. SCATTERED MODERATE/ISOLATED CONVECTION IS WITHIN 120 NM E OF THE WAVE FROM 04N TO 05N. SIMILAR ACTIVITY IS RACING OUT AHEAD OF THE WAVE WITHIN 30 NM OF LINE FROM 05N46W TO 04N51W. THE 24 HOUR FORECAST WILL BRING THE WAVE TO INLAND EASTERN VENEZUELA AND GUYANA...ATTENDANT BY ABUNDANT MOISTURE ALONG WITH SCATTERED TO NUMEROUS SHOWERS AND TSTMS WITH GUSTY WINDS. A TROPICAL WAVE IS MOVING ACROSS THE SOUTHERN CARIBBEAN BASIN WITH AXIS ALONG 70W S OF 14N MOVING W NEAR 20 KT. DURING THE LAST 24 HOURS. STRONG UPPER LEVEL SW WINDS OVER THE EASTERN CARIBBEAN CONTINUE TO LIMIT THE CONVECTION ASSOCIATED WITH THE WAVE TO SCATTERED SHOWERS AND ISOLATED WEAK TSTMS E OF THE WAVE TO 64W. AS THE WAVE CONTINUES WESTWARD OVER THE NEXT 24 HOURS...IT WILL COME UNDER A SUBSTANTIAL AMOUNT SUBSIDENCE/DRY AIR ALOFT THAT WILL KEEP ANY SHOWER/TSTM ACTIVITY THAT OCCURS TO A MINIMUM. A TROPICAL WAVE IS OVER THE SW CARIBBEAN ALONG 81W S OF 15N MOVING W NEAR 15 KT. IT IS PRESENTLY ENHANCING SCATTERED MODERATE/ISOLATED STRONG CONVECTION S OF 10N W OF 80W. THIS WAVE IS FORECAST TO MOVE ACROSS CENTRAL AMERICA S OF THE HONDURAS/NICARAGUA BORDER OVER THE NEXT 24 HOURS...WITH ASSOCIATED TSTM ACTIVITY EXPECTED TO BE CONFINED TO MAINLY FROM SOUTHERN NICARAGUA ON SOUTHWARD AS DRY AIR ALOFT WILL KEEP THE ACTIVITY TO AT MOST ISOLATED IN CONVERGE N OF SOUTHERN NICARAGUA. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH AXIS EXTENDS FROM A 1008 MB LOW ALONG THE AFRICAN COAST NEAR 13N16W SW TO 0522W WHERE THE ITCZ AXIS CONTINUES TO 04N30W. THE ITCZ RESUMES W OF A TROPICAL WAVE FROM 04N33W TO 03N38W TO 03N45W...THEN AGAIN W OF A SECOND TROPICAL WAVE FROM 03N46W TO THE COAST OF S AMERICA NEAR 0N51W. BESIDES THE CONVECTION MENTIONED WITH THE TROPICAL WAVES...SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS NOTED WITHIN 120 NM S OF THE ITCZ BETWEEN 24W-28W...AND ALSO S OF 02N W OF 46W. ISOLATED MODERATE CONVECTION EXISTS ELSEWHERE FROM 01N TO 07N W OF 29W. SCATTERED MODERATE CONVECTION IS WELL S OF THE MONSOON TROUGH FROM 02N TO 06N E OF 17W. ...DISCUSSION... GULF OF MEXICO... UPPER LEVELS...THE EASTERN PERIPHERY OF A BROAD AREA OF MID/UPPER RIDGING COVERS THE MUCH OF THE GULF. A JET STREAM IS EVIDENT ACROSS THE EASTERN PERIPHERY OF THE RIDGING EXTENDING FROM NE TEXAS AT 28N97W SE TO THE NE YUCATAN CHANNEL. NW WINDS OF 60-90 KT SW OF THIS JET STREAM BRANCH ARE ADVECTING DEBRIS MOISTURE...IN THE FORM OF BROKEN CIRRUS CLOUDS...FROM EARLIER DEEP CONVECTION THAT WAS OVER EASTERN MEXICO SEWD TO THE S CENTRAL GULF AND YUCATAN CHANNEL AREA. A PERSISTENT DEEP LAYER LOW IS OVER SOUTHERN ARKANSAS WITH SPOKES OF VORTICITY ROTATING AROUND IT. ITS CORRESPONDING SURFACE LOW OF 1009 MB IS OVER NE LOUISIANA NEAR 33N92W WITH A TROUGH EXTENDING FROM IT SW TO LAKE CHARLES...AND TO 27N96W. LATEST NWS DOPPLER RADAR IMAGERY ALONG WITH SATELLITE ANIMATION SHOW SCATTERED MODERATE/ISOLATED STRONG CONVECTION REMAINING QUITE ACTIVE OUT AHEAD OF THE TROUGH N OF 27N BETWEEN 87W AND 91W. ELSEWHERE AT THE SURFACE...WEAK ATLANTIC RIDGING STRETCHES WESTWARD ROUGHLY ALONG 31N AND W TO NEAR 88W. THE PRES GRADIENT S OF THE RIDGE IS ALLOWING FOR GENERALLY SE TO S 10-15 KT WINDS OVER THE EASTERN GULF...WHILE A LITTLE STRONGER GRADIENT BETWEEN THE RIDGE AND THE SURFACE TROUGH IS ALLOWING FOR S 15-20 KT WINDS OVER THE NORTHERN PORTION OF THE CENTRAL GULF. LIGHT NORTHERLY WINDS ARE W OF THE TROUGH. THE DEEP LAYER LOW WILL REMAIN NEARLY STATIONARY THROUGH MOST OF TODAY BEFORE IT BEGINS TO RETROGRADE BACK TO THE WSW LATER TODAY AND TONIGHT...AND THEN TO THE VICINITY OF EASTERN TEXAS ON FRI AS THE WEAK RIDGE WEAKENS FURTHER. THIS WILL ALLOW FOR THE ATMOSPHERE OVER MUCH OF THE EASTERN AND CENTRAL GULF WILL DESTABILIZE ALLOWING FOR SHOWERS AND TSTMS TO DEVELOP. SOME OF THIS ACTIVITY WILL BE ACCOMPANIED BY GUSTY WINDS. CARIBBEAN SEA... TWO LOW AMPLITUDE TROPICAL WAVES ARE OVER THE SOUTHERN CARIBBEAN SEA AS DESCRIBED ABOVE UNDER TROPICAL WAVE. IN THE UPPER LEVELS....THE SE PERIPHERY OF THE RIDGE MENTIONED ABOVE UNDER GULF OF MEXICO COVERS THE WESTERN CARIBBEAN SEA W OF ABOUT 80W. STRONG NW FLOW OVER THE TOP OF THIS RIDGE IS SENDING HIGH LEVEL MOISTURE...IN THE FORM OF SCATTERED TO BROKEN CIRRUS CLOUDS... SEWD TO THE FAR NW CARIBBEAN. A PERSISTENT UPPER LEVEL TROUGH IS OVER THE REMAINDER OF THE CARIBBEAN WITH AXIS ROUGHLY ALONG 75W. SW FLOW ALOFT E OF THE TROUGH CONTINUES TO ADVECT MAINLY OVERCAST MID/HIGH LEVEL CLOUDS NEWD ACROSS THE EASTERN CARIBBEAN TO THE SE OF A LINE FROM THE VIRGIN ISLANDS SW TO THE COAST OF COLOMBIA AT 12N73W. THE SCATTERED SHOWERS AND ISOLATED TSTMS THAT EARLIER WERE UNDERNEATH THESE CLOUDS HAVE RECENTLY DIMINISHED TO MOSTLY ISOLATED. THE REMAINDER OF THE SEA REMAINS UNDER GENERALLY FAIR CONDITIONS WITH JUST WESTWARD MOVING LOW CLOUDS IN THE TRADE WIND FLOW WITH POSSIBLE ISOLATED SHOWERS. THE UPPER TROUGH IS FORECAST TO CONTINUE TO MOVE E THROUGH THE NEXT 24 HOURS WHILE WEAKENING AS HIGH BECOMES MORE OF THE DOMINANT SYNOPTIC FEATURE OVER THE SEA. ...HISPANIOLA... WESTWARD MOVING LOW LEVEL MOISTURE IN PATCHES ALONG THE BASE OF AN UPPER TROUGH OVER THE ISLAND WILL ALLOW FOR ISOLATED SHOWERS OR TSTMS OVER MOST OF THE ISLAND THROUGH THE NEXT 24 HOURS. ISOLATED TSTMS MAY FORM AGAIN OVER THE WATERS JUST W OF HAITI LATER TODAY AND INTO TONIGHT. STRONG UPPER LEVEL WESTERLY WINDS ACROSS THE BASE OF THE TROUGH WILL TEND TO SHEAR OFF THE TOPS OF THE SHOWER AND TSTM ACTIVITY NOT ALLOWING FOR THEN TO ATTAIN A LONG DURATION OF OCCURRENCE THROUGH FRI NIGHT. ATLANTIC OCEAN... UPPER LEVEL HIGH PRES IS OVER THE CENTRAL ATLANTIC BETWEEN 35W AND 58W WITH THE ASSOCIATED ANTICYCLONE CENTER NEAR 10N53W. TO ITS E...AN UPPER LEVEL TROUGH IS OVER THE EASTERN ATLANTIC N OF 09N. AN UPPER LEVEL LOW IS OVER THE WESTERN ATLANTIC NEAR 27N61W MOVING QUICKLY EASTWARD. A TROUGH EXTENDS FROM THE LOW SW TO HISPANIOLA. A JET STREAM BRANCH WITH A 60-90 KT WIND MAX EXTENDS FROM THE VIRGIN ISLANDS NEWD TO 24N57W...AND TO 27N45W. WATER VAPOR IMAGERY SHOWS A 360 NM WIDE BAND OF BROKEN TO OVERCAST MID/HIGH LEVEL CLOUDS STREAMING NE TO E TO THE S OF THE JET. AT THE SURFACE...A 1028 MB HIGH CENTER IS LOCATED OVER THE EASTERN ATLANTIC NEAR 34N29W WITH A RIDGE EXTENDING SW TO 32N41W TO 27N56W. THE COMBINATION OF THE RIDGE AND UPPER LEVEL HIGH PRES OVER THE AREA IS KEEPING THE EASTERN ATLANTIC PORTION UNDER VERY STABLE ATMOSPHERIC CONDITIONS. A SHORTWAVE TROUGH OVER THE FAR WESTERN PORTION OF THE AREA ALONG 78W IS TRIGGERING OFF A SMALL POCKET OF SCATTERED MODERATE CONVECTION FROM 22N TO 25N BETWEEN 77W AND 79W. THIS ACTIVITY WILL SHIFT EASTWARD OVER THE CENTRAL BAHAMAS AND MOST OF THE SE BAHAMAS THROUGH FRI. E TO SE WINDS OF 10-15 KT ARE NOTED ACROSS THE BASIN N OF 18N W OF 45W...WHILE NE TO E WINDS OF 15-20 KT ARE ELSEWHERE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE