000 AXNT20 KNHC 152353 TWDAT TROPICAL WEATHER DISCUSSION NWS NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT TUE MAR 15 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...ITCZ... ITCZ AXIS IS ANALYZED FROM 05N05W CROSSING THE EQUATOR NEAR 15W TO 01S24W AND INTO NE BRAZIL NEAR 07S35W. SCATTERED MODERATE CONVECTION IS FROM 01N-06N BETWEEN 13W-19W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS FROM THE EQUATOR TO 02N BETWEEN 21W-27W. ...DISCUSSION... GULF OF MEXICO... WATER VAPOR IMAGERY INDICATES AN MIDDLE TO UPPER LEVEL LOW CENTERED OVER THE OHIO RIVER VALLEY THIS EVENING WITH AN UPPER LEVEL TROUGH AXIS EXTENDING SW ACROSS THE LOWER MISSISSIPPI RIVER VALLEY AND EASTERN TEXAS NEAR 29N99W. THE ASSOCIATED COLD FRONT AS OF 15/2100 UTC ENTERS THE NE GULF NEAR PENSACOLA FLORIDA AND EXTENDS SW TO 28N90W WHERE IS BECOMES STATIONARY TO THE TEXAS COAST NEAR 26N97W. LAST FEW VISIBLE SATELLITE IMAGES OF THE DAY INDICATE THE FRONTAL BOUNDARY IS WEAKENING AND BECOMING DIFFUSE WITH VERY LITTLE ISOLATED SHOWER ACTIVITY REMAINING ALONG THE FRONT. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM 30N86W TO 26N88W WITH ISOLATED SHOWERS OCCURRING WITHIN 60 NM EAST OF THE BOUNDARY THIS EVENING. THE FRONT IS FORECAST TO WEAKEN OVER THE NE GULF WITHIN THE NEXT 24 HOURS. THE REMAINDER OF THE GULF THIS EVENING SE OF THE COLD FRONT IS EXPERIENCING RELATIVELY LIGHT EASTERLY WINDS. AS THE CURRENT FRONTAL BOUNDARY EXITS NE OF THE REGION BY EARLY WEDNESDAY... SURFACE HIGH PRESSURE IS EXPECTED TO BUILD BACK IN ACROSS THE GULF AND SE CONUS THROUGH THE REMAINDER OF THE WEEK. CARIBBEAN SEA... AN UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED EAST OF THE LEEWARD ISLANDS NEAR 12N44W THAT EXTENDS AN UPPER LEVEL RIDGE AXIS WESTWARD TO 17N76W WHICH IS PROVIDING THE CARIBBEAN SEA BASIN WITH DRY AIR AND MODERATE SUBSIDENCE ALOFT THIS EVENING. AT THE SURFACE...MODERATE TO FRESH E-NE TRADES ARE EXPECTED TO PREVAIL THROUGH FRIDAY WITH GLOBAL MODEL GUIDANCE INDICATING THE TRADES WILL GRADUALLY INCREASE THROUGH THE WEEKEND DUE TO STRONGER HIGH PRESSURE SETTLING INTO THE SW NORTH ATLC LATE FRIDAY INTO EARLY SATURDAY. TOTAL PRECIPITABLE WATER IMAGERY THIS EVENING INDICATES HIGHER VALUES OF LOW-LEVEL MOISTURE IN THE ATMOSPHERE MOSTLY ACROSS PORTIONS OF THE NW CARIBBEAN S OF 20N W OF 83W...AND AN AREA OVER THE SOUTH-CENTRAL CARIBBEAN S OF 16N BETWEEN 71W-76W. ISOLATED SHOWERS ACCOMPANY THESE AREAS AND WILL ARE EXPECTED TO CONTINUE MOVING WESTWARD THROUGH THE OVERNIGHT HOURS. ATLANTIC OCEAN... MOSTLY WESTERLY ZONAL FLOW ALOFT IS LOCATED OVER THE SW NORTH ATLC W OF 55W. THIS FAIRLY BENIGN UPPER LEVEL PATTERN IS SUPPORTIVE OF A 1027 MB SURFACE HIGH CENTERED NEAR 30N70W WHICH IS PROVIDING MUCH OF THE REGION W OF 60W WITH FAIR CONDITIONS THIS EVENING. FARTHER EAST...A DISSIPATING STATIONARY FRONT ENTERS THE DISCUSSION AREA NEAR 32N53W AND EXTENDS SW ALONG 30N57W TO 27N59W. ISOLATED SHOWERS ARE OCCURRING WITHIN 75 NM EITHER SIDE OF THE BOUNDARY. SOUTH OF THIS DISSIPATING BOUNDARY A WEAK 1017 MB LOW IS CENTERED NEAR 24N58W. A SURFACE TROUGH EXTENDS FROM THE LOW TO 26N56W WITH ISOLATED SHOWERS WITHIN 60 NM OF THE SURFACE TROUGH. ANOTHER SURFACE TROUGH IS ANALYZED EAST OF THE LOW FROM 22N48W TO 26N53W. THIS BOUNDARY LIKELY CURLS INTO THE AFOREMENTIONED LOW HOWEVER...THE STRONGER WIND FIELD OF 20 TO 25 KT E-SE WINDS REMAINS APPROXIMATELY 180 NM NE OF THE BOUNDARY AS CAPTURED BY AN EARLIER MORNING ASCAT PASS. ISOLATED SHOWERS ARE ALSO OCCURRING NE OF THE BOUNDARY FROM 21N-28N BETWEEN 44W-50W. THE REMAINDER OF THE CENTRAL AND EASTERN ATLC IS UNDER THE INFLUENCE OF A SURFACE RIDGE ANCHORED BY A 1027 MB HIGH CENTERED NEAR 33N30W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ HUFFMAN