000 AXNT20 KNHC 122344 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED MAR 12 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND THE 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... ITCZ AXIS IS CENTERED ALONG 5N10W 2N20W CROSSING THE EQUATOR AT 26W THEN ALONG 2S30W 4S40W. LARGE CLUSTERS OF MODERATE TO STRONG CONVECTION ARE OVER LIBERIA...N BRAZIL AND SURINAME. SCATTERED MODERATE CONVECTION IS EITHER SIDE OF THE ITCZ AXIS FROM THE EQUATOR TO 6N BETWEEN 8W-26W. SIMILAR CONVECTION IS NEAR EQ34W. ...DISCUSSION... GULF OF MEXICO... A VIGOROUS SHORTWAVE TROUGH OVER THE N-CENTRAL GULF WATERS WILL MOVE EWD ACROSS N CENTRAL FLORIDA TONIGHT AND TOWARD THE W ATLC THU HELPING TO DEVELOP A SFC LOW JUST E OF THE BAHAMAS. THIS LOW IS EXPECTED TO MOVE ALONG THE WEAK FRONTAL BOUNDARY THAT CURRENTLY CROSSES SOUTH FLORIDA AND THE SE PORTION OF THE GULF INTO THE BAY OF CAMPECHE. A STATIONARY FRONT REMAINS ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS OF MEXICO WHERE SATELLITE IMAGERY SHOWS A RATHER UNIFORM STRATUS CLOUDS COVER. THE REMAINDER OF THE GULF IS UNDER THE INFLUENCE OF A WEAK 1018 MB HIGH LOCATED NEAR 29N93W GIVING THE AREA LIGHT NELY WINDS. MODERATE TO STRONG SUBSIDENCE AND DRY STABLE AIR ARE ACROSS THE N GULF WATERS LIMITING ANY SHOWER ACTIVITY. UPPER LEVEL MOISTURE AHEAD OF ANOTHER SHORT-WAVE TROUGH OVER THE FOUR CORNER AREA AND NW MEXICO IS REACHING THE FAR W GULF AS SEEN ON WV IMAGERY. A JETSTREAM BRANCH WITH CORE WINDS OF 90 TO 110 KT EXTENDS FROM NE MEXICO TO CENTRAL FLORIDA INTO THE W ATLC WHERE IT BECOMES STRONGER. SLY RETURN FLOW WILL INCREASE AHEAD OF THE NEXT COLD FRONT EXPECTED TO MOVE OFF THE TEXAS COAST SAT. CARIBBEAN SEA... BROAD UPPER LEVEL RIDGE DOMINATES THE CARIBBEAN SEA WITH THE RIDGE AXIS EXTENDING FROM CENTRAL AMERICA ACROSS HISPANIOLA INTO THE TROPICAL N ATLANTIC. WATER VAPOR IMAGERY INDICATES THAT STRONG SUBSIDENCE ALOFT ASSOCIATED WITH THIS FEATURE COVERS THE REGION. LIGHT TO MODERATE NE TO E TRADE WINDS CONTINUE TO DOMINATE THE ENTIRE CARIBBEAN COURTESY OF A WEAK HIGH PRES LOCATED N OF AREA. MOIST ONSHORE FLOW IS PRODUCING BROKEN TO OVERCAST LOW LEVEL CLOUDS WITH EMBEDDED LIGHT RAIN BETWEEN WEST PANAMA AND SOUTHERN NICARAGUA. FRAGMENTS OF LOW LEVEL CLOUDS ARE BETWEEN HAITI AND JAMAICA. NO MAJOR CHANGES ARE EXPECTED ON THE WEATHER PATTERN ACROSS THE BASIN THROUGH FRI. ATLANTIC OCEAN... THE DEEP LAYERED TROUGH IS ALONG THE EASTERN SEABOARD MAINLY N OF 30N. THE ATTENDANT COLD FRONT EXTENDS FROM A 1013 MB LOW NEAR 29N78W ACROSS THE NW BAHAMAS AND SOUTH FLORIDA INTO THE SE GULF AND THE BAY OF CAMPECHE. AN AREA OF SHOWERS WITH ISOLATED TSTMS IS WELL AHEAD OF THE FRONT AFFECTING BERMUDA. A WARM FRONT EXTENDS NE FROM THE LOW TO 30N76W...THEN CONTINUES NEWD AS A COLD FRONT TO A DEVELOPING STORM OFF THE NEW ENGLAND COAST. A WEAK FRONTAL BOUNDARY REMAINS OVER THE CENTRAL ATLC ALONG 31N42W 28N52W 30N62W. WEAK RIDGE DOMINATES THE FORECAST AREA EAST OF 70W WITH A COUPLE OF 1020 MB HIGHS NEAR 25N48W AND 30N50W. ALOFT...A BROAD UPPER RIDGE COVERS THE REMAINDER OF THE W ATLC AND INTO THE CENTRAL ATLC WITH MODERATE/STRONG SUBSIDENCE AND DRY STABLE AIR. AS A RESULT...ONLY SCATTERED LOW CLOUDS ARE PRESENT. A SURFACE RIDGE COVERS THE E ATLC E OF 35W ANCHORED BY A 1025 MB HIGH CENTERED MIDWAY BETWEEN THE AZORES AND PORTUGAL. AN UPPER HIGH PERSISTS IN THE TROPICAL ATLC S OF THE CAPE VERDE ISLANDS EXTENDING A RIDGE ALONG WESTERN AFRICA. $$ GR