000 AXNT20 KNHC 082333 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAY 08 2013 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 2315 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS FROM THE COAST OF SENEGAL NEAR 14N17W TO 5N25W. THE ITCZ BEGINS NEAR 5N25 AND CONTINUES ALONG 4N36W EQ42W 1S45W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS FROM 4N-6N BETWEEN 23W-29W. SIMILAR ACTIVITY IS FROM EQ-4N BETWEEN 33W-39W. ...DISCUSSION... GULF OF MEXICO... SURFACE HIGH PRESSURE DOMINATES THE GULF OF MEXICO CENTERED AROUND A 1020 MB HIGH NEAR 28N86W...AS OF 2100 UTC. THE RIDGE IS PROVIDING MOSTLY FAIR CONDITIONS ACROSS THE BASIN WITH CLEAR SKIES AND LIGHT ANTI-CYCLONIC WINDS AROUND THE HIGH. ONLY A FEW LOW LEVEL CLOUDS AND POSSIBLE ISOLATED SHOWERS ARE FROM 23N-25N BETWEEN 88W-93W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE CURRENTLY TO THE WEST OVER TEXAS AND MEXICO. AN UPPER LEVEL TROUGH PRESENTLY RESIDES OVER THE MAJORITY OF THE GULF WITH AXIS EXTENDING ALONG 83W. THE RIDGE IS EXPECTED TO DOMINATE THE BASIN THROUGHOUT THE WEEK AS IT GRADUALLY SHIFTS EAST ALLOWING RETURN FLOW TO INCREASE ACROSS THE WESTERN GULF. CARIBBEAN SEA... A SURFACE TROUGH DOMINATES THE WEATHER PATTERN ACROSS THE CARIBBEAN EXTENDING FROM SOUTH OF HAITI NEAR 18N74W TO THE COAST OF COLOMBIA NEAR 9N76W. THE UPPER TROUGH OVER THE GULF OF MEXICO CONTINUES INTO THE WESTERN CARIBBEAN PROVIDING DIFFLUENCE ALOFT THAT COINCIDES WITH THE SURFACE TROUGH. THIS COMBINATION IS PRODUCING SHOWERS AND THUNDERSTORMS WITHIN 200 NM WEST OF THE TROUGH AXIS...AND WITHIN 90 NM EAST. STRONG SHOWERS AND THUNDERSTORMS ARE ALSO OVER PORTIONS OF PUERTO RICO...ALL OF HISPANIOLA...AND CENTRAL AND EASTERN CUBA. SOME OF THE ACTIVITY NEAR HISPANIOLA IS ALSO CONNECTED TO ANOTHER SURFACE TROUGH NORTH OF THE ISLANDS AS WELL AS A SHEAR AXIS THAT EXTENDS TO JUST NORTH OF THE LEEWARD ISLANDS. THE FAR WESTERN AND FAR EASTERN CARIBBEAN REMAIN MOSTLY CLEAR TO EITHER SIDE OF THE TROUGH. TRADEWIND FLOW OF 15-20 KT IS PRESENT ACROSS THE EASTERN CARIBBEAN BEFORE FLOWING CYCLONICALLY AROUND THE TROUGH. THE TROUGH IS EXPECTED TO DRIFT WESTWARD WITH CONTINUED SHOWER ACTIVITY NEAR IT. HISPANIOLA MAY BE AT RISK OF FLOODING DUE TO THE HEAVY AMOUNTS OF RAINFALL OCCURRING CURRENTLY AND THE POSSIBILITY OF CONTINUED SHOWER ACTIVITY OVER THE NEXT DAY OR SO. ATLANTIC OCEAN... BROAD LOW PRESSURE COVERS THE FAR WEST ATLC ASSOCIATED WITH A DEEP LAYERED TROUGH CENTERED OVER SOUTHERN PENNSYLVANIA. A SURFACE TROUGH ENTERS THE AREA NEAR 32N75W AND EXTENDS TO 29N77W. ISOLATED SHOWERS AND THUNDERSTORMS ARE UP TO 120 NM EAST OF THE AXIS. THE UPPER TROUGH IS ALSO PROVIDING DIFFLUENCE ALOFT NORTH OF THE EASTERN CARIBBEAN SUPPORTING A SURFACE TROUGH ALONG 24N68W TO 20N70W ALONG WITH SCATTERED SHOWERS AND THUNDERSTORMS WITHIN 300 NM TO EITHER SIDE OF THE AXIS. THE REMAINDER OF THE WEST ATLC IS DOMINATED BY SURFACE RIDGING AROUND A 1031 MB HIGH NEAR 38N56W. THE RIDGE IS SUPPORTED BY AN UPPER LEVEL RIDGE ALONG 60W. BROAD UPPER TROUGHING COVERS THE MAJORITY OF THE EASTERN ATLC SUPPORTING A DISSIPATING COLD FRONT ALONG 32N22W 23N28W WITH ISOLATED SHOWERS UP TO 45 NM EITHER SIDE OF THE AXIS. A SURFACE TROUGH TRAILS TO THE WEST FROM A 1016 MB LOW NEAR 32N33W. THE TROUGH CONTINUES ALONG 31N30W 25N34W. POSSIBLE ISOLATED SHOWERS ARE NEAR THE AXIS. A SHEAR AXIS ALSO EXTENDS TOWARDS THE SW OF THE FRONTAL BOUNDARY ALONG 20N36W 16N51W 19N64W. ISOLATED SHOWERS ARE WITHIN 120 NM OF THE AXIS. THE WESTERN PORTION OF THE AXIS IS ALSO CONTRIBUTING TO THE LARGE AREA OF SHOWERS AND THUNDERSTORMS ACROSS THE NORTHERN CARIBBEAN ISLANDS. MOIST CONDITIONS ARE EXPECTED TO REMAIN NEAR AND NORTH OF THE EASTERN AND CENTRAL CARIBBEAN. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE AT THE REQUEST OF METEO-FRANCE AND THE METEOROLOGICAL SERVICES OF HAITI AND THE DOMINICAN REPUBLIC...THE TROPICAL ANALYSIS AND FORECAST BRANCH (TAFB) WILL BEGIN PROVIDING...ON A TEMPORARY BASIS...A SEPARATE DETAILED SECTION WITHIN THE ATLANTIC TROPICAL WEATHER DISCUSSION (TWDAT). IT WILL COVER BOTH HAITI AND THE DOMINICAN REPUBLIC DUE TO THE SHARED GEOGRAPHY OF BOTH COUNTRIES ON THE ISLAND OF HISPANIOLA. THE SECTION BEGINS ON MAY 15 2013 AT 1800 UTC...2 PM EDT. IT WILL PROVIDE GUIDANCE FOR SIGNIFICANT WEATHER EVENTS THAT ARE EXPECTED TO IMPACT THE REGION THROUGH 48 HOURS...WITH THE FOCUS ON ASSESSING THE POTENTIAL FOR HEAVY RAINFALL. $$ WALTON