000 AXNT20 KNHC 271746 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI FEB 27 2009 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...ITCZ... THE ITCZ AXIS IS CENTERED ALONG 5N8W CROSSING THE EQUATOR NEAR 16W EXTENDING TO 2S25W EQ40W INTO NE BRAZIL NEAR 2S49W. SCATTERED MODERATE CONVECTION IS FROM THE EQUATOR TO 5N BETWEEN 43W-50W. A DIFFLUENT PATTERN ALOFT IS HELPING TO INDUCE THIS CONVECTIVE ACTIVITY. SCATTERED MODERATE CONVECTION IS ALSO NOTED ALONG LINE FROM 5N13W TO 4N16W. ...DISCUSSION... GULF OF MEXICO... GENERALLY FAIR WEATHER PERSISTS EARLY THIS AFTERNOON ACROSS MUCH OF THE GULF REGION...WHERE NWLY FLOW ALOFT IS SUPPORTING ATMOSPHERIC SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS. HOWEVER...SOME UPPER LEVEL MOISTURE IS STREAMING SOUTHEASTWARD ACROSS PORTIONS OF THE N AND CENTRAL GULF. THE SUBSIDENCE IS ALSO BEING SUPPORTED BY A SURFACE RIDGE EXTENDING SWWD FROM THE W ATLC ACROSS THE E GULF INTO THE YUCATAN PENINSULA. ACROSS PORTIONS OF THE W GULF...SE TO S SURFACE WINDS OF 20 TO 25 KT ARE PRESENT AROUND THE SURFACE RIDGE. A DEEP LAYERED TROUGH IS ACROSS THE CENTRAL AND SOUTHERN PLAINS OF THE CONUS. THE ATTENDANT STRONG COLD FRONT WILL APPROACH THE TEXAS COAST LATE TONIGHT AND EXTEND FROM THE FLORIDA PANHANDLE TO NEAR TAMPICO MEXICO SAT EVENING...AND FROM TAMPA BAY TO THE YUCATAN PENINSULA EARLY SUN. IN THE WAKE OF THE COLD FRONT...INCREASED NORTHERLY WINDS ARE FORECAST TO OCCUR OVER THE GULF...WITH GALE CONDITIONS EXPECTED SATURDAY NIGHT AND SUNDAY OVER PORTIONS OF THE SW GULF. ALSO...A RELATIVELY COOLER AND DRIER AIR MASS WILL FOLLOW THE FRONT BRINGING ANOTHER ROUND OF COLDER TEMPERATURES ACROSS SOUTH FLORIDA...PARTICULARLY MONDAY AND TUESDAY MORNINGS. CARIBBEAN SEA... A DEEP LAYERED TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A STATIONARY FRONT THAT EXTENDS FROM THE WINDWARD PASSAGE NEAR 29N74W NORTHEASTWARD TO NEAR 30N52W. AT THIS POINT...THE FRONT CONTINUES AS A COLD FRONT OVER THE CENTRAL ATLC. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THIS FRONT. GENERALLY FAIR WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF THE CARIBBEAN REGION...WHERE CONFLUENCE IN W-SW FLOW ALOFT IS PRESENT. AS USUAL...SHALLOW MOISTURE EMBEDDED IN THE TRADE WIND FLOW IS MOVING ACROSS THE BASIN PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. THE GREATEST CONCENTRATION OF THESE SHOWERS IS NOTED JUST N OF THE ABC ISLANDS. ALSO...SOME HIGH CLOUDS ARE OBSERVED ACROSS THE REGION ASSOCIATED WITH A JET STREAM BRANCH WITH CORE WINDS OF 70-90 KT WHICH EXTENDS FROM JAMAICA AND THE WINDWARD PASSAGE ENE OVER THE WEST-CENTRAL ATLC. ATLANTIC OCEAN... AS PREVIOUSLY MENTIONED...A STATIONARY FRONT STRETCHES FROM THE WINDWARD PASSAGE NORTHEASTWARD TO NEAR 30N52W. TO THE W OF THIS FRONT...FAIR WEATHER CONDITIONS PREVAIL THANKS TO 1036 MB SFC HIGH LOCATED NEAR 42N51W. A RIDGE EXTENDS FROM THIS HIGH SWWD ACROSS THE W ATLC INTO FLORIDA AND THE EASTERN GULF. THIS RIDGE ALSO ENVELOPS MOST OF CUBA AND THE NW CARIBBEAN. SE OF THE STATIONARY FRONT...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS SUPPORTING FAIR WEATHER CONDITIONS. A DEEP LAYERED TROUGH DOMINATES THE E ATLC AND EXTENDS FROM AN UPPER-LEVEL LOW SITUATED JUST EAST OF THE MADEIRA ISLANDS NEAR 32N15W TO THE CAPE VERDE ISLANDS. A JET-STREAM BRANCH WITH MAXIMUM WINDS OF 90 KT ROUNDS THE BASE OF THIS TROUGH WHICH IS SUPPORTING A PAIR OF 1012 MB SFC LOWS. ONE IS NEAR 29N19W...THE OTHER IS NEAR 25N18W. THE FIRST ONE IS BETTER DEFINED ON VIS SATELLITE PHOTOS...AND AN EARLIER QSCAT PASS. HOWEVER...BOTH SFC LOWS ARE EXPECTED TO DISSIPATE IN ABOUT 24 HOURS OR SO AS THE UPPER-LEVEL TROUGH MOVES EWD INLAND OVER AFRICA. LOW LEVEL CONVERGENCE AND ATMOSPHERIC INSTABILITY IN THE VICINITY OF THE SURFACE LOWS AND THE ASSOCIATED SURFACE TROUGHS ARE HELPING TO INDUCE ISOLATED TO SCATTERED SHOWERS N OF 25N E OF 21W. AN UPPER LEVEL RIDGE COVERS THE REMAINDER OF THE TROPICAL ATLC ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ. $$ GR/AC