000 AXNT20 KNHC 181745 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST FRI JAN 18 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 6N10W 3N21W 1N30W EQ40W 1S52W. WIDELY SCATTERED MODERATE CONVECTION IS WITHIN 50 NM EITHER SIDE OF AXIS BETWEEN 16W-24W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE NEAR 2N41W AND WITHIN 80 NM N OF AXIS BETWEEN 46W-50W. ...DISCUSSION... GULF OF MEXICO... A GALE CENTER IS TAKING SHAPE OVER THE SW CORNER OF THE GULF. AS A RESULT...A GALE WARNING HAS BEEN ISSUED. AS OF 1500 UTC...A 1012 MB SFC LOW WAS ANALYZED NEAR 21N94W. A STATIONARY FRONT EXTENDS FROM THE LOW NEWD TO SOUTH-CENTRAL FLORIDA NEAR LAKE OKEECHOBEE. SATELLITE IMAGERY REVEALS THAT CLOUDS AND CONVECTION ARE ON THE INCREASE OVER THE WESTERN HALF OF THE GULF...WITH LIGHTNING DATA SHOWING SCATTERED TSTMS...MAINLY NE OF THE LOW CENTER. ANOTHER AREA OF SHOWERS IS OVER THE SE PORTION OF THE GULF NEAR 25N85W ASSOCIATED WITH THE FRONTAL BOUNDARY...WHILE LOW LEVEL CLOUDS WITH EMBEDDED LIGHT RAIN IS SEEN ALONG THE MEXICAN GULF COAST JUST EAST OF THE SIERRA MADRE MOUNTAINS. A SFC TROUGH ALSO EXTENDS NWD FROM THE LOW CENTER TO NEAR 28N95W. A QUIKSCAT PASS FROM AROUND 12Z INDICATED MODERATE TO STRONG ELY WINDS OVER MOST OF THE WESTERN GULF...LIGHTER OVER THE REMAINDER OF THE AREA. ALOFT...A LONGWAVE TROUGH OVER THE CENTRAL CONUS IS SUPPORTING THE DEVELOPING OF THIS GALE CENTER...WHILE THE UPPER LEVEL FLOW REMAINS FROM THE SW OVER THE GULF. THE AFOREMENTIONED FRONTAL BOUNDARY SHOULD BEGIN RETURNING AS A WARM FRONT IN RESPONSE TO THE NEW CYCLOGENESIS PREVIOUSLY MENTIONED. BY TONIGHT THE FRONT WILL EXTEND FROM CENTRAL FLORIDA TO A 1012 MB GALE CENTER NEAR 27N89W AND CONTINUE SW TO NEAR TAMPICO MEXICO. BY SATURDAY AFTERNOON THE LOW WILL MOVE OVER NE FLORIDA WITH A TRAILING COLD FRONT EXTENDING SW TO THE BAY OF CAMPECHE. THE FRONT WILL MOVE ACROSS THE SOUTH FLORIDA AND THE YUCATAN PENINSULA EARLY SUNDAY. IN THE WAKE OF THE FRONT...EXPECT STRONG NLY WINDS AND BUILDING SEAS AS HIGH PRES INVADES THE GULF. CARIBBEAN SEA... A STRONG MID-TO UPPER-LEVEL RIDGE...ANCHORED ON A HIGH OVER COLOMBIA CONTINUES TO DOMINATE THE WEATHER PATTERN ACROSS THE BASIN. THE RIDGE AXIS EXTENDS NWD ALONG 75W TO BEYOND THE BAHAMAS. STRONG SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED WITHIN THE RIDGE AXIS COVERING THE ENTIRE AREA...INCLUDING ALSO CENTRAL AMERICA AND NORTHERN COLOMBIA AND VENEZUELA. DESPITE THIS...A MODERATELY STRONG TRADE WIND FLOW CONTINUES TO PRODUCE SCATTERED BANDS OF SHOWERS FROM PORTIONS OF THE LESSER ANTILLES TO THE GULF OF HONDURAS. THE SHOWERS ARE MORE CONCENTRATED OVER THE NE CARIBBEAN AFFECTING THE UK/US VIRGIN ISLANDS AND PUERTO RICO. IN FACT...THE SAN JUAN DOPPLER RADAR SHOWS SCATTERED TO NUMEROUS SHOWERS MOVING WWD ACROSS THOSE ISLANDS AND REGIONAL COASTAL WATERS. ADDITIONAL CONCENTRATED BANDS OF SHOWERS ARE ALSO OBSERVED IN THE WEST-CENTRAL CARIBBEAN...LIKELY RELATED TO THE SHEAR OF THE LOW-LEVEL WIND/SPEED CONVERGENCE. STRONG TRADES ARE BLOWING ACROSS THE CENTRAL CARIBBEAN WITH AN EARLIER QUIKSCAT PASS SHOWING 20 TO 30 KT JUST OFFSHORE THE COLOMBIAN COAST. A STRONG COLD FRONT IS EXPECTED TO MOVE INTO THE NW CARIBBEAN SAT NIGHT ACCOMPANIED BY STRONG N WINDS AND BUILDING SEAS. ATLANTIC OCEAN... A COLD FRONT IS OVER THE FAR NW PORTION OF THE FORECAST REGION CROSSING SOUTH-CENTRAL FLORIDA AND THE SE QUADRANT OF THE GULF OF MEXICO. ANOTHER COLD FRONT ENTERS THE DISCUSSION AREA NEAR 32N37 THEN CONTINUES SW ACROSS THE OCEAN TO NEAR 21N58W. A BAND OF BROKEN TO OVERCAST LOW CLOUDS AND A FEW SHOWERS ARE WITHIN 90NM EITHER SIDE OF THIS FRONT. SCATTERED MODERATE CONVECTION LIES WITHIN 200 NM E OF THE FRONT FROM 26N TO BEYOND 32N. BETWEEN FRONTS...A 1029 MB SFC HIGH CENTERED WELL N OF AREA DOMINATES. IN THE ERN ATL...A 1036 MB LOCATED OVER PORTUGAL EXTENDS A RIDGE SW TO 25N35W. AT UPPER LEVELS...A BROAD LONGWAVE TROUGH LIES EAST OF THE CARIBBEAN HIGH CENTER...COVERING MUCH OF THE CNTRL AND ERN ATL. AROUND THE BASE OF THE TROUGH...A STRONG 70-90KT JET IS TRANSPORTING CONSIDERABLE UPPER-LEVEL MOISTURE/ HIGH CLOUDS FROM NORTHERN SOUTH AMERICA ALL THE WAY NE TO THE WEST COAST OF AFRICA...PASSING THROUGH THE CAPE VERDE ISLANDS. $$ GR