000 AXNT20 KNHC 201140 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN MAR 20 2011 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTION 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...ITCZ... THE ITCZ AXIS EXTENDS ALONG 02N21W TO THE EQUATOR NEAR 25W THEN ALONG 01S32W TO 01S41 THEN INTO NE BRAZIL NEAR 01S46W. EAST OF 21W...A LOW-LEVEL CYCLONIC CIRCULATION IS OVER W AFRICA NEAR 12N16W WITH STRONG SOUTHWESTERLY FLOW ON THE SOUTHERN PERIPHERY OF THIS CIRCULATION. SCATTERED MODERATE TO STRONG CONVECTION IS FROM 02N-07N BETWEEN 06W-16W. ELSEWHERE...ISOLATED MODERATE CONVECTION IS FROM 01-03N BETWEEN 21W-25W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER CENTRAL MEXICO NEAR 19N99W THAT EXTENDS A RIDGE AXIS NE ACROSS THE WESTERN GULF AND PORTIONS OF THE SE CONUS. MOSTLY SUBSIDENT NORTHWESTERLY FLOW ALOFT IS NOTED ON WATER VAPOR IMAGERY WHICH IS SUPPORTIVE OF A 1025 MB SURFACE HIGH CENTERED OVER THE NE GULF NEAR 28N86W. SHIP AND BUOY OBSERVATIONS INDICATE EAST TO SOUTHEAST WINDS IN THE RANGE OF 10 TO 20 KT ARE ACROSS THE GULF CURRENTLY AND THIS WIND REGIME IS FORECAST TO PERSIST THROUGH WEDNESDAY AS THE HIGH REMAINS STATIONARY WITH AXIS ALONG 28N. SKIES ARE EXPECTED TO REMAIN CLEAR THROUGH THE MORNING HOURS WITH AREAS OF PATCHY TO DENSE FOG POSSIBLE ALONG THE IMMEDIATE GULF COAST WATERS...LIFTING BY LATE MORNING. CARIBBEAN SEA... MOST OF THE CARIBBEAN SEA BASIN IS UNDER THE INFLUENCE OF A BROAD UPPER LEVEL RIDGE CENTERED OVER THE TROPICAL ATLC WITH ASSOCIATED DRY AIR AND SUBSIDENCE. THIS OVERALL PATTERN IS LIMITING ANY SIGNIFICANT DEEP CONVECTION...WITH ONLY A FEW AREAS OF TRADEWIND SHOWERS NOTED ON SATELLITE IMAGERY THIS MORNING. OF NOTE...AN AREA OF ISOLATED SHOWERS REMAINS FOCUSED IN THE VICINITY OF A SHEAR LINE ANALYZED FROM 15N55W TO 11N64W ACROSS THE WINDWARD ISLANDS. THE ACTIVITY COVERS THE AREA FROM 11N-17N BETWEEN 56W-65W. ANOTHER AREA OF ISOLATED SHOWERS IS OCCURRING IN THE GULF OF HONDURAS AND SURROUNDING WATERS FROM 15N-18N BETWEEN 82W-91W...INCLUDING INTERIOR PORTIONS OF HONDURAS... BELIZE...AND GUATEMALA. ALSO...LOW-LEVEL SPEED CONVERGENCE OF THE TRADES OVER THE SW CARIBBEAN IS GENERATING ISOLATED SHOWERS S OF 11N W OF 80W ALONG THE COSTA RICA AND WESTERN PANAMA COAST. ATLANTIC OCEAN... SURFACE HIGH PRESSURE LOCATED OVER THE FLORIDA PENINSULA AND NE GULF OF MEXICO EXTENDS EASTWARD OVER THE SW NORTH ATLC WATERS MAINTAINING OVERALL FAIR CONDITIONS THIS MORNING W OF 58W. A WEAK COLD FRONT IS ANALYZED INTO THE DISCUSSION AREA NEAR 32N65W NEAR BERMUDA TO 30N78W BECOMING STATIONARY TO JACKSONVILLE FLORIDA NEAR 30N81W. VERY LITTLE MIDDLE TO UPPER LEVEL MOISTURE IS ASSOCIATED WITH THE FRONT...HOWEVER...POSSIBLE ISOLATED SHOWERS ARE WITHIN 90 NM NORTH OF AND 120 NM SOUTHEAST OF THE FRONT AS IT CONTINUES TO DRIFT S-SE. AN AREA OF STRONGER NE WINDS IN THE RANGE OF 20 TO 25 KT RESIDES NORTH OF THE FRONT AS DEPICTED BY AN EARLIER 20/0144 UTC ASCAT PASS. FARTHER EAST...AN UPPER LEVEL SHORTWAVE TROUGH IS ALONG 48W AND SUPPORTS A 1009 MB LOW CENTERED NEAR 28N49W. A SURFACE TROUGH EXTENDS S-SW FROM THE LOW ALONG 20N51W TO 16N55W BECOMING A SHEAR LINE TO THE WINDWARD ISLANDS NEAR 13N61W. A WARM FRONT ALSO EXTENDS EAST FROM THE LOW TO 27N44W. LOW-LEVEL CONVERGENCE GENERATED NEAR THE BOUNDARIES ALONG WITH AMPLE MIDDLE TO UPPER LEVEL DIFFLUENCE IN ASSOCIATION WITH THE UPPER LEVEL TROUGH IS GENERATING WIDELY SCATTERED SHOWERS FROM 17N-30N BETWEEN 40W-51W. AN EARLIER ASCAT PASS FROM 20/0000 UTC DEPICTED THE CIRCULATION OF THE LOW WITH STRONG E TO SE WINDS IN THE RANGE OF 20 TO 30 KT COVERING A LARGE AREA WITHIN 360 NM OF THE EASTERN SEMICIRCLE OF THE LOW. THE REMAINDER OF THE EASTERN ATLC IS DOMINATED BY A SURFACE RIDGE ANCHORED ON A 1024 MB HIGH CENTERED NEAR 35N40W SUPPORTING OVERALL FAIR WEATHER CONDITIONS. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN