000 AXNT20 KNHC 072359 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 07 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC... ...SPECIAL FEATURES... A 1007 MB LOW IS CENTERED IN THE WESTERN GULF OF MEXICO NEAR 24N94W AND EXTENDS A SURFACE TROUGH FROM THE LOW TO THE TEXAS COAST NEAR FREEPORT...OR 29N95W. THIS EVENING THE SYSTEM CONTINUES TO ORGANIZE WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION LOCATED FROM 20N-27N BETWEEN 91W-97W. MAXIMUM DAYTIME HEATING AND INSTABILITY HAVE ALSO GENERATED SCATTERED STRONG CONVECTION FARTHER SE AWAY FROM THE LOW-LEVEL CIRCULATION CENTER OVER THE WESTERN YUCATAN PENINSULA FROM 17N-22N BETWEEN 88W-92W. SCATTERED SHOWERS AND ISOLATED TSTMS ARE ELSEWHERE OVER THE WESTERN GULF W OF 88W AND STRETCH INLAND OVER LOUISIANA AND EASTERN TEXAS. WITH THE LOW FORECAST TO TRACK NW OVER THE NEXT 24-36 HOURS...UPPER LEVEL WIND SHEAR VALUES REMAIN LOW AND UPPER LEVEL DIVERGENCE REMAINS HIGH OVER MUCH OF THE WESTERN GULF... PROVIDING THE SYSTEM WITH A FAVORABLE ENVIRONMENT FOR DEVELOPMENT. ...TROPICAL WAVES... TROPICAL WAVE IS FROM 04N15N ALONG 16W MOVING W AT 10-15 KT. UPPER AIR TIME-SECTION ANALYSES FROM DAKAR SENEGAL INDICATES A DEEP LAYER WAVE THAT IS VERY CLOSE TO PASSING THE STATION IN DAKAR. TOTAL PRECIPITABLE WATER IMAGERY AND GLOBAL MODEL GUIDANCE ALSO INDICATES A NORTHERN LOW-LEVEL VORTICITY MAXIMUM HAS EMERGED OFF THE W AFRICA COAST AND IS LOCATED WEST OF THE AXIS NEAR 12N20W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 05N-10N BETWEEN 12W-20W. TROPICAL WAVE EXTENDS FROM 18N42W TO 04N45W MOVING W AT 15-20 KT. BROAD LOW-LEVEL CYCLONIC FLOW IS NEAR THE WAVE AXIS EVIDENT IN SATELLITE IMAGERY AND ALSO LIES WITHIN A DEEP LAYER MOISTURE MAXIMUM INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY BETWEEN 35W-43W. CONVECTION REMAINS SOMEWHAT LIMITED WITH THE WAVE DUE TO A SAHARAN AIR LAYER EAST OF THE WAVE AXIS TO THE W AFRICA COAST...HOWEVER ISOLATED MODERATE CONVECTION IS FROM 09N-14N BETWEEN 43W-50W...AND SCATTERED SHOWERS ARE WITHIN 120 NM EITHER SIDE OF THE WAVE AXIS. TROPICAL WAVE EXTENDS FROM 12N55W TO 06N60W MOVING W AT 10-15 KT. CYCLONIC LOW-LEVEL FLOW IS ABOUT THE WAVE AXIS INDICATED BY SATELLITE IMAGERY AND AN EARLIER WINDSAT SCATTEROMETER PASS. THE WAVE ALSO LIES WITHIN AN AREA OF DEEP LAYER MOISTURE S OF 13N BETWEEN 55W-63W. SCATTERED MODERATE CONVECTION IS FROM 08N-12N BETWEEN 54W-64W. TROPICAL WAVE EXTENDS FROM EASTERN CUBA NEAR 20N75W TO NORTHERN COLOMBIA NEAR 10N75W MOVING W AT 15 KT. THE WAVE CONTINUES TO BE ASSOCIATED WITH AN AREA OF MAXIMUM TOTAL PRECIPITABLE WATER ADVECTING ACROSS THE CENTRAL CARIBBEAN SEA WITH SCATTERED MODERATE AND ISOLATED STRONG CONVECTION FROM 15N-22N BETWEEN 73W-78W. ISOLATED MODERATE TO STRONG CONVECTION IS ALSO FROM 10N-21N BETWEEN 73W-76W. ...ITCZ... ITCZ AXIS IS CENTERED ALONG 08N18W 05N30W 05N43W 08N57W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM 01N-06N BETWEEN 25W-30W...AND FROM THE EQUATOR TO 06N BETWEEN 35W-43W. ...DISCUSSION... GULF OF MEXICO... SIGNIFICANT DEEP LAYER MOISTURE CONTINUES TO IMPACT THE WESTERN GULF DUE TO AN AREA OF LOW PRESSURE CENTERED NEAR 24N94W. A SURFACE TROUGH EXTENDS NORTHWARD TO THE TEXAS COAST NEAR FREEPORT WITH SCATTERED SHOWERS AND ISOLATED TSTMS COVERING MUCH OF THE WESTERN GULF W OF 88W. EAST OF THE SURFACE TROUGH...A STRONG PRESSURE GRADIENT EXISTS IN THE NE QUADRANT OF THE LOW N OF 24N BETWEEN 87W-94W ENHANCING SE WINDS OVER THE BASIN. ALOFT...AN UPPER LEVEL LOW IS CENTERED NEAR 25N97W AND CONTINUES TO SUPPORT THE BROAD SURFACE LOW PRESSURE TO THE SE. WEAK UPPER LEVEL RIDGING COVERS THE NORTH-CENTRAL GULF WITH A NARROW UPPER LEVEL RIDGE AXIS EXTENDING FROM LOUISIANA TO 24N90W. ELSEWHERE THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A SURFACE RIDGE EXTENDING SOUTH TO 27N FROM THE SE CONUS. GENERALLY FAIR WEATHER AND CLEAR SKIES ARE ASSOCIATED WITH THE SURFACE RIDGE... HOWEVER...A FEW ISOLATED SHOWERS AND TSTMS ARE EMBEDDED WITHIN EASTERLY FLOW OVER THE SE GULF AND SOUTHERN FLORIDA PENINSULA THIS EVENING FROM 24N-27N E OF 84W. CARIBBEAN SEA... UPPER LEVEL TROUGHING RESIDES ACROSS MUCH OF THE WESTERN CARIBBEAN AS AN EXTENSION OF AN UPPER LEVEL LOW LOCATED OVER THE SW NORTH ATLC. THE UPPER LEVEL TROUGH AXIS EXTENDS ACROSS EASTERN CUBA AND DIPS SOUTHWARD TO THE SW CARIBBEAN NEAR 12N79W. EVEN THOUGH MOSTLY NORTHERLY FLOW IS NOTED ON WATER VAPOR IMAGERY WEST OF THE TROUGH AXIS...LOW-LEVEL SOUTHEASTERLY FLOW CONTINUES TO ADVECT MOISTURE NW INTO THE SURFACE CIRCULATION LOCATED IN THE WESTERN GULF OF MEXICO WITH ISOLATED SHOWERS POSSIBLE W OF 80W. A TROPICAL WAVE EXTENDS ACROSS THE CENTRAL CARIBBEAN FROM EASTERN CUBA TO NORTHERN COLOMBIA AND CONTINUES TO ENHANCE SCATTERED SHOWERS AND TSTMS FROM 15N-22N BETWEEN 73W-78W. MAXIMUM DAYTIME HEATING AND INSTABILITY IS ALSO GENERATING SCATTERED SHOWERS AND TSTMS OVER CUBA AND HISPANIOLA THIS EVENING. THE REMAINDER OF THE CARIBBEAN IS UNDER GENERALLY CLEAR SKIES DUE TO AN UPPER LEVEL RIDGE COVERING THE EASTERN CARIBBEAN. THE UPPER LEVEL RIDGE AXIS EXTENDS ALONG 12N TO 73W FROM AN UPPER LEVEL ANTICYCLONE CENTERED NEAR 12N61W. ATLANTIC OCEAN... AN UPPER LEVEL LOW IS LOCATED N OF THE DISCUSSION AREA CENTERED NEAR 33N70W WITH AN UPPER LEVEL TROUGH AXIS EXTENDING SOUTHWARD TO THE CENTRAL BAHAMAS AND OVER CENTRAL CUBA. THIS UPPER LEVEL TROUGHING SUPPORTS TWO AREAS OF LOW-LEVEL TROUGHING ACROSS THE W ATLC. THE FIRST IS A SURFACE TROUGH ANALYZED FROM 23N-27N ALONG 78W THAT IS IMPACTING THE NW BAHAMAS WITH SCATTERED SHOWERS AND ISOLATED TSTMS FROM 23N-28N BETWEEN 74W-80W. FARTHER EAST... ANOTHER SURFACE TROUGH EXTENDS INTO THE DISCUSSION AREA NEAR 32N70W TRAILING SOUTHWARD INTO A WEAK 1014 MB LOW NEAR 27N71W THEN CONTINUING SOUTH TO THE CAICOS ISLANDS NEAR 22N72W. SCATTERED SHOWERS AND TSTMS ARE EAST OF THIS SURFACE TROUGH COVERING THE AREA FROM 22N-30N BETWEEN 62W-70W. FARTHER EAST... A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A 1028 MB HIGH CENTERED NEAR 35N44W PROVIDING FOR GENERALLY FAIR CONDITIONS THIS EVENING OVER THE CENTRAL AND EASTERN ATLC. HOWEVER...A SURFACE TROUGH EXTENDS FROM 31N49W TO 24N52W. POSSIBLE ISOLATED SHOWERS ARE WITHIN 200 NM EAST OF THE TROUGH AXIS. ALOFT...AN UPPER LEVEL LOW IS CENTERED NEAR 25N49W THAT EXTENDS TROUGHING TO 15N BETWEEN 45W-60W. EAST OF THE UPPER LEVEL LOW IS AN ANTICYCLONIC CIRCULATION CENTERED NEAR 19N36W THAT ENCOMPASSES THE EASTERN ATLC E OF 42W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN