000 AXNT20 KNHC 220002 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED APR 21 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 2315 UTC... ...THE ITCZ... FROM THE SOUTHERN COAST OF GUINEA TO 4N20W...CROSSING THE EQUATOR ALONG 26W...1S30W...INTO NORTHEASTERN BRAZIL NEAR 4S40W...TO 4S50W. STRONG SHOWERS AND THUNDERSTORMS ARE IN COASTAL LIBERIA. ISOLATED SHOWERS ARE TO THE SOUTH OF 8N TO THE EAST OF 50W. ...DISCUSSION... THE GULF OF MEXICO... AN UPPER LEVEL TROUGH ON TOP OF CALIFORNIA IS DEEPENING...WITH THE BASE OF THE TROUGH REACHING THE EASTERN PACIFIC OCEAN JUST TO THE WEST OF THE NORTHERN BAJA CALIFORNIA PENINSULA. THE DEEPENING TROUGH IS HELPING TO BUILD THE UPPER LEVEL RIDGE AND ITS ACCOMPANYING ANTICYCLONIC FLOW ACROSS MEXICO. A BROAD MIDDLE LEVEL TO UPPER LEVEL TROUGH EXTENDS FROM THE NORTHWESTERN CARIBBEAN SEA JUST OFF THE NORTHEASTERN TIP OF THE YUCATAN PENINSULA BEYOND NORTH CENTRAL FLORIDA AND COASTAL GEORGIA. A SURFACE TROUGH EXTENDS FROM THE CENTRAL STRAITS OF FLORIDA TO THE EAST CENTRAL FLORIDA COAST...STRADDLING THE COAST...AND THEN BEYOND NORTHEASTERN COASTAL FLORIDA. POSSIBLE SHOWERS ARE IN ISOLATED CELLS OF CLOUDS IN THE NORTHEASTERN YUCATAN PENINSULA. SHOWERS ARE POSSIBLE IN THE ATLANTIC OCEAN TO THE NORTH OF 25N BETWEEN 70W AND THE FLORIDA EAST COAST. WEAK SURFACE ANTICYCLONIC FLOW MOVES AROUND A 1016 MB HIGH PRESSURE CENTER THAT IS NEAR 27N88W. THE CARIBBEAN SEA... A SMALL AMOUNT OF MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW FROM THE GULF OF MEXICO TROUGH SPILLS OVER INTO THE NORTHWESTERN CARIBBEAN SEA...TO THE NORTH OF 18N TO THE WEST OF JAMAICA. THE WESTWARD FLOW EVENTUALLY COMBINES WITH THE COMPARATIVELY BROADER UPPER LEVEL SOUTHWESTERLY WIND FLOW THAT HAS BEEN IN PLACE IN THE CARIBBEAN SEA FOR THE LAST FEW DAYS. THE UPPER LEVEL SOUTHWESTERLY WIND FLOW IS ON THE WESTERN SIDE OF LARGE- SCALE ANTICYCLONIC FLOW THAT COVERS THE ATLANTIC OCEAN. IT IS POSSIBLE THAT AFTERNOON HEATING IN BROAD AND WEAK SURFACE LOW PRESSURE MAY HAVE BEEN HELPING TO START SOME SHOWERS AND THUNDERSTORMS IN THE EASTERN DOMINICAN REPUBLIC AND IN THE COASTAL PLAINS OF NORTHERN PUERTO RICO...AND FARTHER AWAY IN COASTAL AREAS OF NORTH CENTRAL VENEZUELA AND JUST TO THE WEST OF LAKE MARACAIBO IN EXTREME NORTHWESTERN VENEZUELA. THE ATLANTIC OCEAN... PRACTICALLY ALL THE MIDDLE LEVEL TO UPPER LEVEL CYCLONIC FLOW IN THE AREA IS ALONG AND TO THE NORTH OF 32N BETWEEN 35W AND 65W. THE TROUGH THAT IS TO THE NORTH OF THE AREA SUPPORTS THE COLD FRONT THAT PASSES THROUGH 32N41W TO 26N50W 24N57W TO A 1010 MB LOW PRESSURE CENTER THAT IS NEAR 26N63W. THE COLD FRONT CONTINUES FROM THE LOW PRESSURE CENTER TO 23N69W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND POSSIBLE SHOWERS ARE WITHIN 60 NM TO 90 NM ON EITHER SIDE OF THE LINE THAT PASSES THROUGH 31N38W 25N50W 23N60W 20N66W. BROKEN TO OVERCAST MULTILAYERED CLOUDS COVER THE AREA FROM 25N TO 30N BETWEEN 55W AND 70W. BROAD UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA TO THE SOUTH OF 32N BETWEEN 20W AND 70W. SURFACE ANTICYCLONIC FLOW COVERS THE AREA TO THE NORTH OF 10N BETWEEN AFRICA AND 44W... AROUND A 1018 MB HIGH PRESSURE CENTER THAT IS NEAR 26N28W. FOR ADDITIONAL INFORMATION PLEASE VISIT HTTP://WWW.HURRICANES.GOV/MARINE $$ MT