000 AXNT20 KNHC 232315 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT FRI APR 23 2010 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...METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2245 UTC... ...THE ITCZ... FROM THE COAST OF SIERRA LEONE NEAR 8N13W TO 5N20W TO 3N30W 3N40W...INTO THE NORTHEASTERN COAST OF BRAZIL NEAR 2N51W. CONVECTIVE DEBRIS CLOUDS FROM EARLIER PRECIPITATION COVERS THE AREA FROM 7N TO 10N BETWEEN 55W AND 60W. THE CLOUDS ARE IN AN AREA OF A SURFACE TROUGH THAT IS ALONG 56W/57W TO THE SOUTH OF 10N. ISOLATED MODERATE SHOWERS ARE TO THE SOUTH OF 8N13W 6N20W 7N45W 6N52W. ...DISCUSSION... THE GULF OF MEXICO... UPPER LEVEL CYCLONIC FLOW COVERS A LARGE AREA OF THE U.S.A.... AROUND A TROUGH THAT GOES FROM THE EASTERN PACIFIC OCEAN NEAR 24N120W...ACROSS BAJA CALIFORNIA AND NORTHWESTERN MEXICO BEYOND 30N110W...INTO A CYCLONIC CIRCULATION CENTER THAT IS IN NORTHEASTERN COLORADO. UPPER LEVEL SOUTHWESTERLY WIND FLOW AND DRY AIR IN SUBSIDENCE ARE TO THE NORTH OF THE LINE THAT GOES FROM THE SOUTHERN TIP OF BAJA CALIFORNIA BEYOND THE TEXAS/MEXICO BORDER THAT IS NEAR 27N100W. A COLD FRONT RUNS THROUGH TEXAS FROM 29N101W NORTHEASTWARD BEYOND 31N97W. A BROAD AREA OF LOW PRESSURE/SURFACE TROUGH IS IN MEXICO ALONG 25N100W 20N97W BEYOND 16N91W INTO GUATEMALA. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS MEXICO TO THE SOUTH OF THE BAJA-27N100W LINE...AND ACROSS THE OPEN WATERS OF THE GULF OF MEXICO. SOME OF THE FLOW IN THE EASTERN GULF OF MEXICO BECOMES PURE WESTERLY AND IT EVENTUALLY MOVES ACROSS FLORIDA INTO THE WESTERN ATLANTIC OCEAN. HIGH CLOUDS ACCOMPANY THE UPPER LEVEL ANTICYCLONIC FLOW ACROSS PRACTICALLY THE ENTIRE AREA...EXCEPT FOR A LITTLE BIT OF THE EAST CENTRAL GULF. A COLD FRONT IS FORECAST TO MOVE OFF THE TEXAS GULF COAST LATE TONIGHT. THE FRONT WILL STRETCH FROM SOUTHEASTERN LOUISIANA TO VERACRUZ MEXICO ON SATURDAY EVENING. IT WILL WEAKEN RAPIDLY INTO A FRONTAL TROUGH WHILE IT EXTENDS FROM THE FLORIDA PANHANDLE TO THE SOUTHEASTERN BAY OF CAMPECHE ON SUNDAY EVENING. IT WILL MOVE TO THE SOUTHEAST OF THE GULF BY MONDAY EVENING. A WEAK TROUGH WILL DEVELOP IN THE BAY OF CAMPECHE ON SUNDAY NIGHT AND MONDAY WITH HIGH PRESSURE ACROSS THE REMAINDER OF THE GULF BY LATE TUESDAY. THE CARIBBEAN SEA... UPPER LEVEL SOUTHWESTERLY WIND FLOW COVERS THE ENTIRE AREA. HIGH CLOUDS ARE SPILLING INTO THE AREA TO THE NORTHWEST OF THE LINE FROM HONDURAS TO THE CUBA COAST NEAR 21N78W. THESE CLOUDS ARE COMING FROM THE ANTICYCLONIC FLOW THAT IS CURVING FROM MEXICO INTO THE SOUTHERN GULF OF MEXICO AND BEYOND INTO THE NORTHWESTERN CORNER OF THE AREA. BROAD SURFACE CYCLONIC FLOW IS IN THE LOW CLOUD FIELD TO THE SOUTH OF 17N TO THE EAST OF 82W. SHOWERS AND THUNDERSTORMS IN AFTERNOON HEATING AND ATMOSPHERIC INSTABILITY ARE IN CENTRAL PUERTO RICO AND IN THE EASTERN DOMINICAN REPUBLIC. THE SURFACE PRESSURE GRADIENT IS COMPARATIVELY WEAK RIGHT NOW. TRADEWINDS WILL INCREASE IN THE CENTRAL AND SOUTHWESTER CARIBBEAN SEA AS HIGH PRESSURE BUILDS TO THE NORTH OF THE AREA. SOUTHEASTERLY WINDS WILL INCREASE IN THE GULF OF HONDURAS THROUGH EARLY NEXT WEEK. A WEAK TROUGH OF LOW PRES MAY DEVELOP IN THE SOUTHWESTERN CARIBBEAN SEA ON MONDAY. A SERIES OF WEAK FRONTAL TROUGHS WILL MOVE SOUTHEASTWARD THROUGH THE NORTHERN PART OF THE TROPICAL NORTH ATLANTIC OCEAN WITH BUILDING NORTHWESTERLY SWELL ARRIVING LATE SUNDAY AND MONDAY. TRADEWINDS AND SEAS WILL INCREASE IN THE SOUTHERN PART OF THE TROPICAL NORTH ATLANTIC OCEAN ON MONDAY AND TUESDAY. THE ATLANTIC OCEAN... BROAD AND GENTLE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW WITH A TROUGH COVERS THE AREA TO THE NORTH OF 26N TO THE WEST OF 30W. A COLD FRONT PASSES THROUGH 32N52W TO 28N56W TO 25N62W. SHOWERS ARE IN A CLOUD CLUSTER THAT IS WITHIN A 30 NM RADIUS OF 22N46.5W. OTHER SHOWERS ARE TO THE NORTH OF 31N BETWEEN 44W AND 48W. SURFACE ANTICYCLONIC WIND FLOW COVERS THE AREA TO THE NORTH OF 22N BETWEEN 67W AND THE SOUTHEASTERN U.S.A. AN EASTERN ATLANTIC OCEAN COLD FRONT PASSES THROUGH 32N24W TO 28N30W TO 24N42W. THIS FRONT IS BEING SUPPORTED BY AN UPPER LEVEL TROUGH THAT PASSES THROUGH 34N25W TO 30N30W. A 1018 MB SURFACE HIGH PRESSURE CENTER IS NEAR 29N37W. SURFACE PRESSURE IS WITHIN 200 NM TO 240 NM ON EITHER SIDE OF A RIDGE THAT PASSES THROUGH A 1017 MB HIGH PRESSURE CENTER THAT IS NEAR 33N15W TO A 1018 MB HIGH PRESSURE CENTER THAT IS NEAR 23N29W...TO 17N45W AND 18N56W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT