000 AXNT20 KNHC 041035 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT THU APR 04 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...THE ITCZ/THE MONSOON TROUGH... THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL ATLC NEAR 12N16W AND CONTINUES ALONG 5N16W TO 1N23W WHERE THE ITCZ BEGINS AND CONTINUES ALONG 1N30W THEN S OF THE EQUATOR NEAR 36W. CLUSTERS OF SCATTERED MODERATE/ISOLATED STRONG CONVECTION ARE FROM 6N TO JUST S OF THE EQUATOR BETWEEN THE PRIME MERIDIAN AND 27W. ...DISCUSSION... GULF OF MEXICO... A BROAD UPPER TROUGH DIPS S FROM THE CENTRAL PLAIN STATES OVER MEXICO AND THE FAR NW GULF WHILE A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE GULF ANCHORED OVER SOUTH AMERICA. A COMPLEX LOW PRESSURE SYSTEM REMAINS OVER THE GULF AT 04/0900 UTC WITH A 1009 MB LOW OFF THE COAST OF FLORIDA NEAR 29N86W AND A COLD FRONT EXTENDING SW ALONG 27N90W 25N93W WHERE IT BECOMES STATIONARY TO INLAND OVER MEXICO NEAR TAMPICO. A WARM FRONT EXTENDS E FROM THE 1009 MB LOW TO INLAND OVER FLORIDA NEAR CEDAR KEY TO 28N82W. THE SECOND LOW HAS DISSIPATED WITH A SURFACE TROUGH REMAINING FROM 24N92W EXTENDING S TO THE BAY OF CAMPECHE NEAR 19N95W. SCATTERED TO HEAVY SHOWERS WITH SCATTERED THUNDERSTORMS ARE WITHIN 240 NM E OF THE COLD FRONT N OF 24N. A SURFACE RIDGE IS BEGINNING TO BUILD S OVER TEXAS INTO THE FAR W GULF ANCHORED BY A 1025 MB HIGH OVER OKLAHOMA. DENSE LOW LEVEL CLOUDS WITH PATCHES OF FOG BEING REPORTED OVER THE AREA NW OF LINE FROM PENSACOLA FLORIDA TO MEXICO NEAR 25N97W. THE LOW WILL MOVE NE ACROSS N FLORIDA TODAY. A COLD FRONT WILL REACH FROM SW FLORIDA TO THE YUCATAN PENINSULA FRI AND EXIT THE REGION FRI NIGHT. HIGH PRESSURE BEHIND THE FRONT WILL SHIFT E SAT AND ALLOW SOUTHERLY RETURN FLOW LATE SAT THROUGH MON. CARIBBEAN SEA... A BROAD UPPER RIDGE DOMINATES THE CARIBBEAN AND MOST OF THE GULF OF MEXICO ANCHORED INLAND OVER SOUTH AMERICA. RELATIVE TIGHT PRESSURE GRADIENT EXISTS BETWEEN THE LOWER PRESSURE OF SOUTH AMERICA AND THE SURFACE RIDGE OVER THE W ATLC PRODUCING FRESH TO STRONG EASTERLY TRADE WINDS ACROSS THE S/CENTRAL CARIBBEAN WITH MODERATE TO FRESH TRADE WINDS ELSEWHERE. THE MONSOON TROUGH EXTENDS ACROSS THE SW CARIBBEAN FROM COLOMBIA TO COSTA RICA INTO THE E PACIFIC REGION. ISOLATED SHOWERS ARE S OF 13N BETWEEN 76W- 84W. WATER VAPOR IMAGERY INDICATES STRONG SUBSIDENCE ACROSS MOST OF THE BASIN GIVING THE CARIBBEAN FAIR CONDITIONS ACROSS THE REMAINDER OF THE AREA. FRESH TO STRONG SE WINDS IN THE GULF OF HONDURAS WILL DIMINISH TONIGHT. THE REMAINDER OF THE TRADE WINDS WILL PERSIST THROUGH MON. A COLD FRONT WILL MOVE THROUGH THE YUCATAN CHANNEL TONIGHT WILL GRADUALLY WEAKEN IN THE NW CARIBBEAN FRI THEN DISSIPATE SAT. ATLANTIC OCEAN... SCATTERED SHOWERS/ISOLATED THUNDERSTORMS ARE OVER THE FAR W ATLC N OF 28N W OF 72W ASSOCIATED WITH THE FRONTAL SYSTEM IN THE GULF OF MEXICO. BROAD UPPER RIDGE FROM THE CARIBBEAN COVERS THE W ATLC. A WEAK SURFACE RIDGE COVERS THE ATLC ANCHORED BY A 1024 MB HIGH NEAR BERMUDA NEAR 32N66W. AN UPPER TROUGH EXTENDS OVER THE W/CENTRAL ATLC N OF 23N FROM 42W-56W SUPPORTING A WEAKENING COLD FRONT THAT ENTERS THE REGION NEAR 32N52W TO 25N62W. ISOLATED SHOWERS ARE POSSIBLE WITHIN 60 NM E OF THE FRONT. A LARGE SURFACE RIDGE DOMINATES THE REMAINDER OF THE ATLC ANCHORED BY A 1028 MB HIGH NEAR 31N39W GIVING THE REMAINDER OF THE ATLC FAIR WEATHER THIS MORNING. SOUTHERLY WINDS WILL INCREASE TODAY AHEAD OF A LOW PRESSURE SYSTEM IN THE GULF OF MEXICO. THE LOW WILL MOVE N OF THE AREA LATE TONIGHT AND DRAG A COLD FRONT INTO REGION FRI. THE FRONT WILL REACH FROM 32N74W TO THE STRAITS OF FLORIDA FRI AND FROM BERMUDA TO THE WINDWARD PASSAGE SAT. THE FRONT IS EXPECTED TO STALL AND WEAKEN SUN THEN DISSIPATE MON. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ PAW