000 AXNT20 KNHC 090002 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED AUG 08 2012 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 WWW UTC. ...SPECIAL FEATURE... TROPICAL STORM ERNESTO IS CENTERED NEAR 18.7N 91.5W...AS OF 0000 UTC...OR ABOUT 15 NM ENE OF CIUDAD DEL CARMEN MEXICO. ERNESTO IS MOVING W AT 7 KT. MINIMUM CENTRAL PRESSURE IS 994 MB WITH MAXIMUM SUSTAINED WINDS OF 45 KT WITH GUSTS TO 55 KT. ERNESTO IS ABOUT TO EMERGE BACK OVER WATER AND THERE IS A SMALL WINDOW FOR SOME STRENGTHENING BEFORE MOVING BACK OVER LAND LATER TOMORROW. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT5/WTNT25 KNHC AND THE PUBLIC ADVISORY UNDER AWIPS/WMO MIATCPAT5/WTNT35 KNHC FOR MORE DETAILS. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 17N-20N BETWEEN 87W-97W...AND FROM 20N-25N BETWEEN 91W-97W. TROPICAL WAVE IS ALONG 18N35W TO A 1010 MB SURFACE LOW AT 14N36W MOVING W NEAR 12 KT. LOW-LEVEL CYCLONIC FLOW IS AROUND THE LOW CENTER AND THE WAVE. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS MAINLY W OF THE LOW CENTER FROM 14N-16N BETWEEN 37W-40W...AND FROM 13N-14N BETWEEN 34W-36W. THE SYSTEM HAS BECOME SLIGHTLY BETTER ORGANIZED AND UPPER LEVEL CONDITIONS COULD BECOME MORE CONDUCIVE FOR FURTHER DEVELOPMENT OF THE SYSTEM OVER THE NEXT COUPLE OF DAYS. ...TROPICAL WAVES... TROPICAL WAVE IS ALONG 23N54W TO 17N59W MOVING NW NEAR 20 KT. THIS OPEN WAVE IS THE REMNANTS OF T.S. FLORENCE THAT DISSIPATED SEVERAL DAYS AGO. SATELLITE IMAGERY INDICATES BROAD LOW-LEVEL CYCLONIC FLOW IS AROUND THE WAVE AXIS. THE WAVE ALSO LIES IN THE MIDDLE OF A SURGE OF DEEP LAYER MOISTURE PRESENT IN TOTAL PRECIPITABLE WATER IMAGERY. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 19N-23N BETWEEN 56W-61W. TROPICAL WAVE IS MOVING THROUGH THE CENTRAL CARIBBEAN ALONG 20N71W TO 12N74W MOVING W NEAR 15-20 KT. A LARGE AREA OF ENHANCED DEEP LAYER MOISTURE IS PRESENT ACROSS THE CENTRAL AND EASTERN CARIBBEAN ASSOCIATED WITH THE WAVE AS WELL AS AN UPPER LEVEL LOW CENTERED N OF JAMAICA NEAR 19N77W. THE UPPER LEVEL LOW IS PROVIDING A LARGE AREA OF DIFFLUENCE ALOFT ACROSS THE CENTRAL AND EASTERN CARIBBEAN. IT IS HARD TO DIFFERENTIATE WHAT AREAS OF CONVECTION ARE ASSOCIATED WITH THE WAVE AND WITH THE UPPER LOW. REGARDLESS OF THE CAUSE...SCATTERED STRONG CONVECTION IS FROM 15N-17N BETWEEN 67W-74W...AND FROM 19N-21N BETWEEN 71W-75W. SCATTERED MODERATE CONVECTION IS FROM 17N-20N BETWEEN 66W-71W. HEAVY RAINFALL AND FLOODING ALONG WITH MUDSLIDES ARE POSSIBLE ACROSS MUCH OF THE NORTHERN CARIBBEAN ISLANDS. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST OF MAURITANIA AT 18N16W WHERE IT CONTINUES OVER WATER ALONG 16N24W 15N31W. THE ITCZ BEGINS ON THE W SIDE OF A TROPICAL WAVE/LOW ALONG 12N38W 9N48W 9N57W. SCATTERED MODERATE CONVECTION IS FROM 10N-11N BETWEEN 39W-43W. SCATTERED STRONG CONVECTION IS FROM 7N-9N BETWEEN 46W-50W. ...DISCUSSION... THE GULF OF MEXICO... TROPICAL STORM ERNESTO IS BRINGING WIND AND RAIN TO THE SW GULF OF MEXICO. SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE S OF 25N BETWEEN 90W-98W. SEE SPECIAL FEATURES FOR MORE DETAILS ABOUT ERNESTO. THE REMAINDER OF THE GULF WATERS ARE MOSTLY CLEAR DUE TO DRY AIR ALOFT AROUND AN UPPER LEVEL RIDGE...OUTFLOW FROM ERNESTO...THAT COVERS THE NORTHERN HALF OF THE BASIN. AN UPPER LEVEL TROUGH TO THE N OVER THE EASTERN CONUS IS HELPING SUPPORT SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE NE GULF COAST AND ACROSS PORTIONS OF THE FLORIDA PENINSULA. CYCLONIC FLOW IS ACROSS THE SOUTHERN GULF AROUND ERNESTO...WHILE LIGHT ANTI-CYCLONIC FLOW IS ACROSS THE NORTHERN GULF AROUND A WEAK SURFACE RIDGE. STRONG WINDS AND RAIN WILL REMAIN OVER THE SW GULF AS ERNESTO EMERGES OVER WATER AND MAKES A SECOND LANDFALL LATER TOMORROW. WEAK SURFACE RIDGING WILL BUILD ACROSS THE BASIN WITH SHOWERS/THUNDERSTORMS REMAINING OVER THE NE GULF COAST. THE CARIBBEAN SEA... A FEW SHOWERS REMAIN OVER THE FAR NW CARIBBEAN ASSOCIATED WITH TROPICAL STORM ERNESTO MOVING ACROSS THE YUCATAN PENINSULA. AN UPPER LEVEL LOW COVERS MUCH OF THE BASIN CENTERED N OF JAMAICA NEAR 19N77W. DRY AIR ALOFT IS WRAPPING AROUND THE NW SIDE OF THE LOW...WHILE MOISTURE FROM ERNESTO IS BEGIN DRAWN AROUND THE SOUTHERN PORTION AND INTO THE DIFFLUENT E SIDE OF THE LOW. A TROPICAL WAVE IS ALSO ACROSS THE CENTRAL CARIBBEAN FROM CENTRAL HISPANIOLA TO N OF COLOMBIA. THE COMBINATION OF THE WAVE AND THE UPPER LOW IS SUPPORTING SHOWERS/THUNDERSTORMS ACROSS MUCH OF THE NORTHERN CARIBBEAN INCLUDING PUERTO RICO...HISPANIOLA...AND EASTERN CUBA. HEAVY RAINFALL...FLOODING...AND MUDSLIDES ARE POSSIBLE IN AREAS THAT HAVE ALREADY RECEIVED LARGE AMOUNTS OF PRECIPITATION. SHOWERS/THUNDERSTORMS ARE ALSO ACROSS THE SW CARIBBEAN INCLUDING COSTA RICA AND PANAMA ASSOCIATED WITH THE E PACIFIC MONSOON TROUGH THAT EXTENDS THROUGH BOTH COUNTRIES TO NORTHERN COLOMBIA. EXPECT MOIST CONDITIONS TO REMAIN OVER THE CENTRAL CARIBBEAN AND BEGIN TO SPREAD OVER THE WESTERN CARIBBEAN AS THE WAVE CONTINUES WESTWARD. THE ATLANTIC OCEAN... BROAD SURFACE RIDGING COVERS THE ATLC ANCHORED BY A 1025 MB HIGH NEAR 33N48W. DRY AIR ALOFT BETWEEN AN UPPER LEVEL RIDGE CENTERED NEAR 34N69W AND AN UPPER LEVEL LOW OVER THE N CENTRAL CARIBBEAN IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE W ATLC. AN AREA OF SHOWERS/THUNDERSTORMS IS JUST OFFSHORE OF N FLORIDA ASSOCIATED WITH AN UPPER LEVEL TROUGH OVER THE EASTERN CONUS. SCATTERED SHOWERS/POSSIBLE THUNDERSTORMS ARE ALSO N OF THE CENTRAL CARIBBEAN TIED TO THE UPPER LEVEL LOW MENTIONED ABOVE...AND A TROPICAL WAVE IN THE CENTRAL CARIBBEAN. AN UPPER LEVEL TROUGH ALONG 34N53W TO 27N60W IS SUPPORTING A SURFACE TROUGH ALONG 30N64W TO 26N67W. ISOLATED SHOWERS ARE WITHIN 100 NM E OF THE AXIS. A TROPICAL WAVE NE OF THE NORTHERN LEEWARD ISLANDS IS SUPPORTING SCATTERED SHOWERS/THUNDERSTORMS FROM 19N-23N BETWEEN 55W-62W. BROAD UPPER LEVEL RIDGING COVERS THE REMAINDER OF THE TROPICAL ATLC EXCEPT FOR A BROAD UPPER TROUGH ALONG 27W. VISIBLE SATELLITE IMAGERY INDICATES THAT A BROAD AREA OF AFRICAN DUST EXTENDS ACROSS THE ATLC AROUND THE TWO TROPICAL WAVES SUPPORTING FAIR CONDITIONS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ WALTON