000 AXNT20 KNHC 290003 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAR 28 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 2345 UTC. ...ITCZ/MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS W AFRICA TO THE COAST LIBERIA AT 6N10W AND CONTINUES TO 3N21W...WHERE LOW LEVEL WINDS SUGGEST THE ITCZ THEN CONTINUES FROM 3N21W TO 3N31W TO THE EQUATOR NEAR 41W AND TO THE COAST OF BRAZIL. SCATTERED MODERATE CONVECTION IS ALONG AND WITHIN 60 NM S OF THE ITCZ BETWEEN 21W-23W...AND ALSO BETWEEN 38W-40W. ...DISCUSSION... GULF OF MEXICO... ALOFT...UPPER LEVEL RIDGING EXISTS OVER MUCH OF THE AREA E OF 94W. IT IS REFLECTED AT THE SURFACE AS A RIDGE THAT EXTENDS FROM A 1023 MB HIGH CENTER OVER FAR SW GEORGIA W TO ERN TEXAS. SHORTWAVE ENERGY OVER CENTRAL TEXAS IS TRANSLATING EWD WITH TIME. WITH IT...UPPER LEVEL MOISTURE IN THE FORM OF SCATTERED TO BROKEN HIGH LEVEL CLOUDS IS SEEN ON WATER VAPOR IMAGERY ADVECTING EWD ACROSS MOST OF THE WRN GULF AND INTO THE FAR WESTERN PART OF THE CENTRAL GULF. ELSEWHERE...MOSTLY MODERATE SUBSIDENCE REMAINS IN PLACE MAINTAIN PRETTY MUCH STABLE ATMOSPHERIC CONDITIONS. A MOIST SE SURFACE WIND FLOW CONSISTING OF 10-15 KT AROUND THE SRN PERIPHERY OF THE RIDGE IS MARKED BY A FEW SMALL PATCHES OF BROKEN LOW TO MID LEVEL CLOUDS MOVING NWD WITH ISOLATED SHOWERS OVER THE CENTRAL AND ERN PORTIONS OF THE GULF AND THOROUGH THE STRAITS OF FLORIDA. THESE PATCHES OF MOISTURE ARE ATTRIBUTED TO A DECAYING ATLC FRONTAL BOUNDARY SE OF THE BAHAMAS. ELSEWHERE ...FAIR TO MOSTLY CLEAR SKIES ARE NOTED. BESIDES THE UPPER LEVEL MOISTURE GRADUALLY SPREADING EWD ACROSS THE WRN AND CENTRAL SECTIONS THROUGH THE NEXT COUPLE OF DAYS...LITTLE OVERALL CHANGES CAN BE EXPECTED OTHERWISE. CARIBBEAN SEA... ALOFT...MAINLY SW FLOW UNDER MODERATE CONDITIONS COVERS MUCH OF THE WRN SECTION OF THE SEA. THE ASSOCIATED RATHER TRANQUIL ATMOSPHERIC CONDITIONS ARE CONTINUING...AND ARE EXPECTED TO CHANGE LITTLE THROUGH THE NEXT 48 HRS. A LIGHT SURFACE PRES GRADIENT EXISTS THROUGHOUT INDUCING NE-E TRADE WINDS OF 15 KT. WITH THIS WIND FLOW...SCATTERED LOW CLOUDS WITH ISOLATED SHOWERS MOVING WWD ARE SEEN PRIMARILY S OF 17N. SMALL PATCHES OF BROKEN LOW CLOUDS WITH ISOLATED SHOWERS ARE MOVING NWD OVER THE FAR NW PART OF THE CARIBBEAN...AND THROUGH THE YUCATAN CHANNEL INTO THE FAR SRN GULF OF MEXICO. A STRONGER PRES GRADIENT IN THE SW PORTION OF THE SEA IS ALLOWING FOR NE 20-25 KT WINDS THERE. THE RESULTANT LOW-LEVEL SPEED CONVERGENCE ALONG THE COASTS OF COSTA RICA AND PANAMA IS BRINGING ISOLATED SHOWERS TO THOSE PARTICULAR COAST LINES. THE NRN CARIBBEAN ISLANDS INCLUDING PUERTO RICO AND HISPANIOLA ARE ALSO EXPERIENCING SHOWERS DUE TO A WEAKENING COLD FRONT TO THE N OF THE AREA. VISIBLE SATELLITE IMAGERY ALONG WITH GOES-R DUST ENHANCEMENTS INDICATE THAT AN AREA OF AFRICAN DUST CONTINUES TO MOVE OVER THE ERN CARIBBEAN WHERE SOME OF THE SURFACE STATIONS ARE REPORTING DUST. EXPECT LITTLE CHANGE OVER THE NEXT 24-48 HOURS. ATLANTIC OCEAN... NOW THAT THE DEEP LAYER TROUGH THAT WAS PRESENT OVER THE WRN ATLC HAS SHIFTED EWD...UPPER LEVEL RIDGING IS FILLING IN BEHIND IT COVERING THIS PART OF THE ATLC. IT SUPPORTS SURFACE RIDGING GENERALLY TO THE W OF 62W WHICH IS ANCHORED BY A 1024 MB HIGH CENTER AT 31N72W. THE RIDGE COMBINED WITH DRY AIR ALOFT IS PROVIDING STABLE CONDITIONS ACROSS THE W ATLC. THE DEEP LAYER TROUGH IS NOW OVER THE CENTRAL PART OF THE ATLC N OF 24N BETWEEN 40W AND 56W WITH ITS AXIS ROUGHLY 50W. IT SUPPORTS A COLD FRONT THAT ENTERS THE DISCUSSION AREA THROUGH 32N47W...AND EXTENDS SW TO 25N50W TO 21N60W WHERE BEGINS TO DISSIPATE AROUND THE SRN PERIPHERY OF THE RIDGE AS IT BARELY IDENTIFIABLE ON SATELLITE IMAGERY AS IT REACHES TO NE DOMINICAN REPUBLIC. SCATTERED SHOWERS ARE WITHIN 75 NM E OF THE FRONT N OF 26N...AND WITHIN 30 NM OF THE FRONT W OF 61W. AN ACTIVE PRE-FRONTAL TROUGH UNDER AN UPPER LEVEL DIFFLUENT PATTERN E OF THE DEEP LAYER TROUGH IS IDENTIFIED TO THE E OF THE COLD FRONT EXTENDING FROM A PSN AT 29N46W TO 25N48W TO 20N53W. SCATTERED TO NUMEROUS SHOWERS AND ISOLATED TSTMS ARE WITHIN 300 NM E OF THE TROUGH. AN UPPER LEVEL SHORTWAVE RIDGE IS NOTED TO THE E OF THE DEEP LAYER TROUGH COVERING THE ERN ATLC REGION WITH A MEAN AXIS ALONG 40W. IT SUPPORTS A 1021 MB SURFACE HIGH JUST N OF THE DISCUSSION AT 33N28W...WHICH IS PROVIDING FAIR CONDITIONS ACROSS THE REMAINDER OF THE ATLC. OVER THE FAR ERN ATLC...AN UPPER LEVEL TROUGH IS JUST APPROACHING THE COAST OF AFRICA ALONG 18W. IT IS HELPING TO KEEP IN PLACE A SURFACE LOW OVER NW AFRICA JUST N OF THE AREA AT 33N8W. A SURFACE TROUGH EXTENDS FROM THE LOW CENTER TO THE CANARY ISLANDS NEAR 27N16W. OVER THE TROPICAL ATLC BROAD UPPER LEVEL RIDGING IS PRESENT S OF 24N BETWEEN 39W AND 68W. STRONG WLY WINDS ALOFT ARE ALONG THE NORTHERN CREST OF THIS RIDGE AS A JET STREAM BRANCH RIDES UP FROM FAR ERN PACIFIC...NEWD ACROSS THE SW CARIBBEAN SE AND NE TO OVER THE CREST OF THE RIDGE AND ACROSS THE BASE OF THE CENTRAL ATLC DEEP LAYER TROUGH. UPPER LEVEL MOISTURE IN THE FORM OF SCATTERED TO BROKEN HIGH CIRRUS CLOUDS ARE BEING CHANNELED NE AND E UP OVER THE RIDGE IN THE WLY FLOW. LAST VISIBLE SATELLITE IMAGERY ALONG WITH GOES-R DUST ENHANCEMENTS REVEALED THAT AN AREA OF AFRICAN DUST EXTENDED ACROSS THE TROPICAL ATLC TO THE ERN CARIBBEAN MOSTLY S OF 20N REACHING...BUT EXTENDING FARTHER N ALONG THE AFRICAN COAST. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ AGUIRRE