000 AXNT20 KNHC 191758 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI AUG 19 2011 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 1715 UTC. ...SPECIAL FEATURE... TROPICAL DEPRESSION EIGHT HAS NOW BEEN UPGRADED TO TROPICAL STORM HARVERY AS OF 19/1800. HARVEY IS CENTERED NEAR 16.3N 84.2W OR ABOUT 135 NM E OF ISLA ROATAN HONDURAS. HARVEY IS MOVING W NEAR 9 KT. MINIMUM CENTRAL PRESSURE IS 1005 MB. MAXIMUM SUSTAINED WIND SPEED IS 35 KT WITH GUSTS TO 45 KT. FOR MORE DETAILS REFER TO PUBLIC ADVISORIES ISSUED UNDER WMO HEADER WTNT33 KNHC AND UNDER AWIPS HEADER MIATCPAT3. FORECAST/ADVISORIES ARE ISSUED UNDER WMO HEADER WTNT22 KNHC AND UNDER AWIPS HEADER MIATCMAT3. NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS MAINLY N OF THE CENTER FROM 15N-18N BETWEEN 81W-88W IMPACTING EXTREME NRN HONDURAS. THE HEAVY RAINFALL ACROSS NRN HONDURAS...GUATEMALA...AND BELIZE OVER THE NEXT COUPLE OF DAYS COULD CAUSE POTENTIAL FLOODING AND MUDSLIDES. A WELL-DEFINED TROPICAL WAVE IS JUST OFF THE WRN COAST OF AFRICA ALONG 17N19W MOVING W AT 10-15 KT. LOW-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS CONCENTRATED NEAR 13N AROUND A 1006 MB SURFACE LOW. TOTAL PRECIPITABLE WATER IMAGERY INDICATES HIGH MOISTURE VALUES SURROUND THE WAVE. SCATTERED MODERATE/STRONG CONVECTION IS FROM 14N-16N BETWEEN 17W-23W....AND FROM 9N-12N BETWEEN 24W-30W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 8N-12N BETWEEN 17W-24W. WHILE THE CONVECTION IS DISORGANIZED AT THIS TIME...THE UPPER-LEVEL ENVIRONMENT IS FAVORABLE FOR FURTHER DEVELOPMENT. ANOTHER WELL-DEFINED WAVE IS IN THE CENTRAL TRPCL ATLC ALONG 17N48W TO 9N47W WITH CYCLONIC FLOW CONCENTRATED ALONG THE AXIS AROUND A 1006 MB LOW NEAR 13N. THIS SYSTEM IS MOVING W NEAR 20 KT. CONVECTION NEAR THE WAVE HAS INCREASED OVER THE PAST 24 HOURS. CURRENTLY NUMEROUS MODERATE/SCATTERED STRONG CONVECTION IS MAINLY W OF THE WAVE FROM 13N-17N BETWEEN 47W-53W...AND SE OF THE AXIS FROM 6N-9N BETWEEN 42W-47W. UPPER LEVEL CONDITIONS ARE EXPECTED TO BECOME MORE CONDUCIVE FOR FURTHER DEVELOPMENT OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... SEE SPECIAL FEATURES SECTION FOR DETAILS ON THE TROPICAL WAVES. ...THE ITCZ/THE MONSOON TROUGH... THE ACTIVE TRPCL WAVE OVER THE FAR ERN TRPCL ATLC HAS SPLIT THE MONSOON TROUGH. ONE SECTION REMAINS INLAND OVER AFRICA...WHILE THE OTHER CONTINUES ON THE W SIDE OF THE TRPCL WAVE ALONG 13N22W 11N35W TO THE TRPCL WAVE IN THE CENTRAL TRPCL ATLC NEAR 13N48W. CONVECTION NEAR THE MONSOON TROUGH HAS BEEN ASSOCIATED WITH THE TROPICAL WAVES AND IS DISCUSSED IN THE SPECIAL FEATURES SECTION. ...DISCUSSION... THE GULF OF MEXICO... UPPER LEVEL RIDGING COVERS MUCH OF THE GULF OF MEXICO CENTERED OVER WRN TEXAS. WATER VAPOR IMAGERY ALSO INDICATES MOSTLY DRY AIR ALOFT COVERING THE AREA. THIS IS MAINTAINING MOSTLY FAIR WEATHER AND LIGHT SURFACE FLOW. WEAK HIGH PRESSURE IS CENTERED OVER ERN MEXICO NEAR 21N98W. A FEW ISOLATED SHOWERS/THUNDERSTORMS ARE NOTED OVER THE SE GULF S OF 27N E OF 83W ASSOCIATED WITH AN AREA OF DEEP LAYER MOISTURE EVIDENT IN TOTAL PRECIPITABLE WATER IMAGERY. EXPECT WEAK RIDGING TO FORM OVER THE NE GULF WITH RELATIVELY LIGHT ANTI-CYCLONIC FLOW AROUND IT. THE CARIBBEAN SEA... T.S. HARVERY IS CURRENTLY IMPACTING NRN HONDURAS AND HEADING WWD TOWARDS THE BAY ISLANDS OF HONDURAS AND BELIZE. SEE SPECIAL FEATURES SECTION FOR MORE DETAILS. SCATTERED SHOWERS/THUNDERSTORMS ARE ACROSS THE SW CARIBBEAN FROM 10N-12N BETWEEN 81W-83W...AND S OF 12N TO PANAMA BETWEEN 75W-80W ASSOCIATED WITH THE MONSOON TROUGH THAT EXTENDS FROM THE E PACIFIC ACROSS COSTA RICA AND PANAMA TO NRN COLOMBIA. ALOFT...AN UPPER LEVEL RIDGE IS CENTERED OVER THE FAR NW CARIBBEAN NEAR 20N85W. UPPER LEVEL TROUGHING COVERS THE ERN ATLC EXTENDING FROM THE ATLC ACCOMPANIED BY MODERATE DRY AIR ALOFT. THIS IS MAINTAINING MOSTLY FAIR CONDITIONS ACROSS THE ERN CARIBBEAN WITH AREAS OF ISOLATED SHOWERS EMBEDDED WITHIN THE TRADEWIND FLOW. EXPECT T.S. HARVEY TO CONTINUE TO IMPACT PORTIONS OF THE NW CARIBBEAN. AN ACTIVE TROPICAL WAVE STILL E OF THE LESSER ANTILLES MAY BEGIN IMPACTING THE ERN ISLANDS WITHIN THE NEXT 24-36 HOURS. SEE SPECIAL FEATURES FOR MORE DETAILS ON THIS WAVE. THE ATLANTIC OCEAN... A LARGE AREA OF SCATTERED SHOWERS/THUNDERSTORMS IS OVER THE WRN ATLC W OF 73W ACROSS THE NW BAHAMAS AND REACHING S FLORIDA ASSOCIATED WITH A SHORTWAVE UPPER TROUGH EXTENDING FROM 35N74W TO 28N80W. A WEAK UPPER RIDGE IS TO THE E ACROSS THE CENTRAL BAHAMAS TO 31N65W. ANOTHER UPPER LEVEL TROUGH IS FROM 31N57W TO THE ERN CARIBBEAN. THIS UPPER TROUGH IS SUPPORTING A WEAK SURFACE TROUGH ALONG 32N54W TO 28N57W WITH ISOLATED SHOWERS WITHIN 90 NM EITHER SIDE THE AXIS. THE REMAINDER OF THE BASIN IS DOMINATED BY SURFACE RIDGING AROUND A 1026 MB HIGH NEAR 39N29W PROVIDING MOSTLY FAIR WEATHER. ALOFT...A PAIR OF UPPER RIDGES ARE CENTERED NEAR 25N48W...AND 34N33W SUPPORTING THE SURFACE RIDGE. AN UPPER LEVEL TROUGH IS TO THE E ALONG 15W N OF 25N. VISIBLE SATELLITE IMAGERY CONTINUES TO SHOW AN AREA OF DUST E OF 50W TO THE N OF THE TROPICAL WAVES. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON