000 AXNT20 KNHC 220002 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED JUL 21 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 FEATURE... A SURFACE TROUGH IS ALONG 26N70W IN THE ATLANTIC OCEAN TO THE DOMINICAN REPUBLIC NEAR 18N72W. BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE AREA BETWEEN 60W AND 77W. STRONG SHOWERS AND THUNDERSTORMS COVER THE CARIBBEAN SEA AND ATLANTIC OCEAN FROM 17N TO 22N BETWEEN 64W IN THE VIRGIN ISLANDS AND 77W IN JAMAICA. AN UPPER LEVEL TROUGH GOES FROM 31N72W TO A 27N73W CYCLONIC CIRCULATION CENTER...TO SOUTHEASTERN CUBA NEAR 20N77W TO JUST TO THE SOUTH OF JAMAICA NEAR 17N77W. UPPER LEVEL ANTICYCLONIC FLOW CURVES SOUTHEASTWARD...EVENTUALLY RUNNING INTO THE CYCLONIC FLOW OF THE TROUGH/CYCLONIC FLOW THAT IS BETWEEN 50W AND 60W. DATA FROM THE NOAA G-IV JET INDICATE THAT UPPER-LEVEL WINDS ARE NOT CONDUCIVE FOR DEVELOPMENT AT THIS TIME...ALTHOUGH THEY MAY BECOME MARGINALLY FAVORABLE IN A DAY OR TWO. LOCALLY HEAVY SHOWERS AND GUSTY WINDS ASSOCIATED WITH THIS AREA OF WEATHER WILL SPREAD ACROSS THE BAHAMAS...SECTIONS OF CUBA...AND SOUTHERN FLORIDA DURING THE NEXT COUPLE OF DAYS AS THE SYSTEM MOVES WESTWARD OR WEST-NORTHWESTWARD 10 TO 15 MPH. THE CHANCE THAT THIS SYSTEM MAY BECOME A TROPICAL CYCLONE DURING THE NEXT 48 HOURS IS MEDIUM. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 15N37W TO 7N36W TO 3N35W...MOVING WEST 10 KT. IT IS NOT EASY TO DETERMINE WHICH PRECIPITATION IS JUST ASSOCIATED WITH THIS WAVE AND WHICH PRECIPITATION JUST IS ASSOCIATED WITH THE ITCZ. NO SIGNIFICANT AND ORGANIZED DEEP CONVECTIVE PRECIPITATION IS NEAR THE WAVE. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 77W/78W TO THE SOUTH OF 17N AND JAMAICA...MOVING WESTWARD 10 KT. NO SIGNIFICANT AND ORGANIZED DEEP CONVECTIVE PRECIPITATION IS NEAR THE WAVE. ...THE ITCZ... 13N17W 9N28W 7N34W 7N44W 8N53W 10N61W. CYCLONIC FLOW IN THE LOW CLOUDS OF THE DAY'S LAST VISIBLE IMAGERY BETWEEN 23W AND 27W IS BEING RELATED TO A TROPICAL WAVE THAT IS ALONG 25W/26W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS ARE FROM 8N TO 10N BETWEEN 26W AND 32W...FROM 1N TO 2N BETWEEN 33W AND 35W...AND FROM 9N TO 12N BETWEEN 53W AND 57W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE TO THE SOUTH OF 10N BETWEEN 36W AND 50W. ...DISCUSSION... THE GULF OF MEXICO... A SURFACE TROUGH CURVES FROM THE COASTAL PLAINS OF MEXICO... IN THE SOUTHWESTERN GULF OF MEXICO...TO 24N96W AND 29N95W. STRONG SHOWERS AND THUNDERSTORMS ARE IN THE NORTHEASTERN COASTAL AREA OF THE YUCATAN PENINSULA...TO MEXICO AND WESTERN-BORDERING GUATEMALA...INTO THE SOUTHWESTERN CORNER OF THE GULF OF MEXICO WITHIN A 60 NM RADIUS OF 20N93W...NORTHWARD BETWEEN 90W AND 100W IN THE GULF WATERS. AN UPPER LEVEL CYCLONIC CENTER IS NEAR 27N99W ALONG THE TEXAS/MEXICO BORDER. UPPER LEVEL ANTICYCLONIC OUTFLOW MOVES SOUTHEASTWARD...COVERING THE GULF OF MEXICO BETWEEN 84W AND 90W. THE CARIBBEAN SEA... CLOUDS...SHOWERS...AND THUNDERSTORMS COVER THE ATLANTIC OCEAN AND THE CARIBBEAN SEA FROM 10N TO 17N BETWEEN 58W AND 67W... INCLUDING THE EASTERN CARIBBEAN SEA ISLANDS. THE 24-HOUR RAINFALL TOTAL FOR GUADELOUPE FOR 21/1200 UTC WAS 2.26 INCHES. THIS AREA IS TO THE SOUTHWEST OF THE UPPER LEVEL 19N57W CYCLONIC CIRCULATION CENTER...IN AN AREA OF DIFFLUENT UPPER LEVEL WIND FLOW THAT IS HELPING TO INCREASE THE CLOUDS AND PRECIPITATION. STRONG SHOWERS AND THUNDERSTORMS HAVE BEEN OCCURRING IN NORTHWESTERN VENEZUELA TO THE EAST OF LAKE MARACAIBO...AND IN NORTHERN COASTAL COLOMBIA TO THE NORTH OF 10N...IN BROAD LOW PRESSURE THAT RUNS FROM THE SURFACE INTO THE LOWER LEVELS OF THE ATMOSPHERE. THE ATLANTIC OCEAN... AN UPPER LEVEL TROUGH IS ALONG 29N53W 23N56W...TO A POSSIBLE CYCLONIC CENTER NEAR 19N57W...TO 11N54W. DRY AIR IN SUBSIDENCE SURROUNDS THIS TROUGH. A SURFACE TROUGH IS ALONG 30N46W 24N44W 18N42W. BROKEN LOW CLOUDS AND POSSIBLE SHOWERS ARE TO THE NORTH OF 12N BETWEEN 40W AND 50W. THIS SURFACE TROUGH USED TO BE THE NORTHERN EXTENSION OF THE 15N37W 3N35W TROPICAL WAVE. AN UPPER LEVEL TROUGH IS ALONG 31N10W TO 25N22W TO 22N27W...SURROUNDED BY DRY AIR IN SUBSIDENCE. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT