000 AXNT20 KNHC 071748 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1700 UTC... ...SPECIAL FEATURE... A BROAD AREA OF LOW PRESSURE IS NW OF THE YUCATAN PENINSULA ANALYZED AS A SURFACE TROUGH EXTENDING FROM 28N95W NEAR HOUSTON TEXAS TO A 1007 MB LOW CENTER NEAR 23N93W TO 21N92W...AS OF 1500 UTC. SCATTERED MODERATE/STRONG CONVECTION IS NEAR THE LOW CENTER FROM 21N-24N BETWEEN 89W-94W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO S OF LOUISIANA/TEXAS FROM 26N-31N BETWEEN 90W-96W...AND FROM 24N-27N BETWEEN 93W-94W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ALONG THE SRN TEXAS COASTLINE. THE SHOWER/THUNDERSTORM ACTIVITY HAS BECOME A LITTLE MORE ORGANIZED NEAR THE LOW CENTER. ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE AND A TROPICAL DEPRESSION COULD FORM BEFORE THE SYSTEM REACHES NE MEXICO OR SE TEXAS AS IT MOVES WNW AT 10-15 KT. ...TROPICAL WAVES... TROPICAL WAVE IS APPROACHING THE W AFRICA COAST ALONG 15W/16W S OF 17N. A NORTHERN LOW-LEVEL DRY VORTICITY CENTER IS NEAR THE NRN EXTEND OF THE WAVE AXIS ANALYZED AS A 1006 MB LOW NEAR 17N15W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 5N-9N BETWEEN 12W-19W. TROPICAL WAVE IS ALONG 41W/42W S OF 18N MOVING W 15-20 KT. BROAD CYCLONIC FLOW IS ABOUT THE WAVE AXIS EVIDENT IN VISIBLE SATELLITE IMAGERY. THE WAVE ALSO LIES AHEAD OF A DEEP LAYER MOISTURE MAXIMUM INDICATED BY TOTAL PRECIPITABLE WATER IMAGERY. ISOLATED MODERATE/STRONG CONVECTION IS W OF THE AXIS FROM 9N-14N BETWEEN 42W-48W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO S OF THE AXIS FROM 1S-5N BETWEEN 34W-44W. IT IS UNCERTAIN WHETHER THE ACTIVITY S OF THE AXIS IS SOLELY INFLUENCED BY THE TROPICAL WAVE. TROPICAL WAVE EXTENDS FROM 12N54W TO 6N60W MOVING W 10-15 KT. CYCLONIC FLOW IS ABOUT THE WAVE AXIS INDICATED BY VISIBLE SATELLITE IMAGERY AND WINDSAT SCATTEROMETER DATA. WAVE LIES AHEAD OF A SLIGHT BULGE IN DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 9N-12N BETWEEN 54W-57W...AND FROM 9N-12N BETWEEN 59W-63W. TROPICAL WAVE EXTENDS FROM S OF ERN CUBA NEAR 20N75W TO NRN COLOMBIA NEAR 10N72W MOVING W NEAR 15 KT. WAVE IS AHEAD OF A DEEP LAYER MOISTURE MAXIMUM EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS INLAND OVER COLOMBIA FROM 7N-10N BETWEEN 74W-76W. ISOLATED MODERATE/STRONG CONVECTION IS FROM 16W-21W BETWEEN 73W-77W. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N13W 4N27W 9N42W 10N56W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 2N-5N BETWEEN 24W-29W. ...DISCUSSION... GULF OF MEXICO... SIGNIFICANT DEEP LAYER MOISTURE CONTINUES TO IMPACT THE CENTRAL AND NW GULF OF MEXICO TODAY DUE TO A BROAD AREA OF LOW PRESSURE NW OF THE YUCATAN PENINSULA ANALYZED AS A SURFACE TROUGH EXTENDING FROM 28N95W NEAR HOUSTON TEXAS TO A 1007 MB LOW CENTER NEAR 23N93W TO 21N92W...AS OF 1500 UTC. SCATTERED MODERATE/STRONG CONVECTION IS NEAR THE LOW CENTER FROM 21N-24N BETWEEN 89W-94W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS ALSO S OF LOUISIANA/TEXAS FROM 26N-31N BETWEEN 90W-96W...AND FROM 24N-27N BETWEEN 93W-94W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ALONG THE SRN TEXAS COASTLINE. THE STRONG PRESSURE GRADIENT BETWEEN THE LOW PRESSURE IN THE GULF AND HIGH PRESSURE ACROSS THE ERN UNITED STATES IS SUPPORTING SE-S WINDS OF 20-30 KT E OF THE TROUGH AXIS TO 86W. SEE SPECIAL FEATURES ABOVE FOR MORE DETAILS ON THIS SYSTEM. ALOFT...AN UPPER LEVEL LOW IS CENTERED S OF BROWNSVILLE TEXAS NEAR 25N97W SUPPORTING THE BROAD SURFACE LOW PRESSURE TO THE SE. THE UPPER LOW IS ACCOMPANIED BY DRY AIR ALOFT KEEPING THE REMAINDER OF THE SW CARIBBEAN UNDER GENERALLY FAIR CONDITIONS. WEAK UPPER LEVEL RIDGING COVERS THE CENTRAL GULF WITH A NARROW UPPER LEVEL TROUGH COVERING THE ERN GULF EXTENDING FROM AN UPPER LEVEL LOW IN THE W ATLC WITH AXIS EXTENDING ACROSS THE BAHAMAS OVER THE SE GULF TO THE NE FLORIDA PANHANDLE. WATER VAPOR IMAGERY INDICATES DRY AIR INTRUDING OVER THE NE GULF BEHIND THIS UPPER TROUGH KEEPING SURFACE CONDITIONS FAIR. EXPECT SHOWER/THUNDERSTORM ACTIVITY TO CONTINUE ACROSS THE WRN GULF DUE TO THE AREA OF LOW PRESSURE WHICH IS FORECAST TO MOVE WNW TOWARDS SE TEXAS/NE MEXICO OVER THE NEXT DAY OR SO. CARIBBEAN SEA... POSSIBLE ISOLATED SHOWERS ARE ACROSS THE NW CARIBBEAN AND CUBA THIS AFTERNOON DUE TO MOISTURE LEFT BEHIND BY THE AREA OF LOW PRESSURE NOW NW OF THE YUCATAN PENINSULA. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN DUE TO SURFACE CONVERGENCE NEAR A PORTION OF THE ITCZ THAT EXTENDS ACROSS COSTA RICA TO THE NRN COLOMBIA COAST ALONG 10N84W 11N80W 9N75W. THE REMAINDER OF THE WRN CARIBBEAN IS EXPERIENCING GENERALLY FAIR WEATHER DUE TO AN AREA OF DRY AIR ALOFT AROUND A WEAK UPPER LEVEL TROUGH OVER THE S CENTRAL CARIBBEAN. A TROPICAL WAVE EXTENDING FROM ERN CUBA TO THE NRN COLOMBIA COAST IS ENHANCING SCATTERED SHOWERS/THUNDERSTORMS ACROSS ERN CUBA AND THE WATERS TO THE S FROM 16W-21W BETWEEN 73W-77W. ISOLATED SHOWERS/THUNDERSTORMS ARE ALSO E OF THE WAVE S OF HISPANIOLA FROM 14N-17N BETWEEN 68W-76W. THE REMAINDER OF THE BASIN IS UNDER MAINLY CLEAR SKIES AND FAIR WEATHER UNDER THE INFLUENCE OF AN UPPER LEVEL RIDGE COVERING THE ERN CARIBBEAN CENTERED NEAR 13N63W. DRY AIR IS ALSO FILTERING IN FROM THE ATLC. EXPECT SHOWER ACTIVITY TO REMAIN NEAR THE TROPICAL WAVE AS IT PROGRESSES WWD. SHOWERS/THUNDERSTORMS WILL START IMPACTING THE WINDWARD ISLANDS AND ERN CARIBBEAN AS A TROPICAL WAVE E OF THE BASIN APPROACHES THE AREA OVER THE NEXT 24 HRS. ATLANTIC OCEAN... AN UPPER LEVEL LOW SPINNING N OF THE DISCUSSION AREA NEAR 33N68W WITH AXIS CONTINUING ACROSS THE BAHAMAS TO THE STRAITS OF FLORIDA AND INTO THE SE GULF IS SUPPORTING SEVERAL WAVES OF ENERGY ACROSS THE W ATLC ANALYZED AS A PAIR OF SURFACE TROUGHS. THE FIRST IS ANALYZED FROM 30N65W TO 27N75W. THE SECOND IS ALONG 27N64W 24N71W. THE COMBINATION OF THESE FEATURES IS ENHANCING NUMEROUS STRONG CONVECTION FROM 22N-26N BETWEEN 68W-71W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO FROM 22N-27N BETWEEN 64W-68W...AND FROM 26N-33N BETWEEN 59W-65W. SCATTERED SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE NW BAHAMAS FROM 23N-26N BETWEEN 76W-80W SUPPORTED BY THE NARROW EXTENSION OF THE UPPER LEVEL TROUGH TOWARDS THE SE GULF. POSSIBLE ISOLATED SHOWERS ARE ACROSS THE REMAINDER OF THE W ATLC. FARTHER E...A BROAD SURFACE RIDGE DOMINATES ANCHORED BY A PAIR OF 1029 AND 1028 MB HIGHS LOCATED NEAR 40N30W AND 37NM45W RESPECTIVELY KEEPING CONDITIONS FAIR ACROSS THE ERN ATLC. HOWEVER...A SURFACE TROUGH EXTENDS FROM 31N46W TO 22N46W. POSSIBLE ISOLATED SHOWERS ARE ALONG THE TROUGH AXIS. ALOFT...AN UPPER LEVEL TROUGH IS BETWEEN 42W-58W CENTERED NEAR 25N48W...WITH AN UPPER LEVEL RIDGE TO THE E BETWEEN 22W-42W CENTERED NEAR 19N34W. AN UPPER LEVEL TROUGH EXTENDING FROM THE PORTUGAL COAST COVERS THE FAR ERN ATLC E OF THE CAPE VERDE ISLANDS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON