000 AXNT20 KNHC 152323 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT SUN APR 15 2007 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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 5N9W 1N20W EQ30W CROSSING THE EQ NEAR 40W INTO NE BRAZIL NEAR 1S46W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM EITHER SIDE OF THE AXIS BETWEEN 14W-17W AND 26W-32W. ...DISCUSSION... GULF OF MEXICO... A MUCH COLDER AND DRIER AIRMASS HAS NOW SETTLED IN AS THE STRONG COLD FRONT HAS PUSHED THROUGH. A FAIRLY TIGHT PRES GRADIENT BETWEEN A MODERATE HIGH PRES RIDGE OVER TEXAS AND ERN MEXICO AND A RAPIDLY DEEPENING LOW PRES SYSTEM IN THE MID-ATLANTIC STATES IS PRODUCING STRONG N-NWLY WINDS IN THE GULF ESP E OF 90W. THESE WINDS ARE PRODUCING SEAS IN THE 8 TO 14 FT RANGE. WIDESPREAD BROKEN COLD AIR STRATOCUMULUS CLOUDS ARE CLEARLY SEEN ON SAT IMAGES INDICATING THE COLD AIR. THE ONLY AREA OF THICKER LOW CLOUDS IS OVER THE HIGH TERRAIN OF THE LOWER SIERRA MADRE MOUNTAINS IN MEXICO WHERE THE TAIL END OF THE STATIONARY FRONT IS STILL HUNG UP. IN THE MID AND UPPER LEVELS...CONFLUENCE ON THE S SIDE OF AN UPPER TROUGH IS PROVIDING ABUNDANT SUBSIDENCE N OF 25N. ELSEWHERE SCATTERED HIGH CLOUDS ARE FILTERING IN BY S AND SWLY UPPER FLOW BETWEEN A STRONG RIDGE IN THE CARIB AND A SHARP SHORTWAVE TROUGH OVER NRN BAJA. OVER THE NEXT COUPLE OF DAYS...WINDS AND SEAS WILL SUBSIDE AS HIGH PRES MOVES E CENTERING ITSELF ACROSS THE AREA LATE MON AND TUES. CARIBBEAN SEA... THE STRONG COLD FRONT HAS JUST ENTERED THE NW CARIB EXTENDING FROM THE FL KEYS ACROSS WRN CUBA TO THE YUCATAN PENINSULA ALONG 24N81W 20N86W 17N91W. A NARROW LINE...ABOUT 90 NM....OF SHOWERS AND TSTMS ARE AHEAD OF THE FRONT N OF 20N WITH THE STRONGEST ACTIVITY OVER WRN CUBA AND THE NEARBY WATERS AS CLOUD TOP TEMPS ARE APPROACHING -80 C. THIS FRONT HAS BROUGHT MUCH COOLER AIR TO THE NRN YUCATAN WITH TEMPS AT LEAST 20 F DEG COOLER THAN YESTERDAY AT THIS TIME. THE REMAINDER OF THE REGION CONTINUES ITS TRANQUIL WEATHER UNDER THE INFLUENCE OF A STRONG UPPER HIGH CENTERED NEAR 16N72W AND ABUNDANT DRY STABLE AIR ALOFT. THE TRADES ARE LIGHT TO MODERATE ACROSS MUCH OF THE AREA DUE TO THE WEAK PRES GRADIENT. HOWEVER...BEHIND THE FRONT N-NW WINDS INCREASE TO 20-25 KT ADVECTING IN THE COOLER AIRMASS. OVER THE NEXT COUPLE OF DAYS...THE FRONT IS EXPECTED TO PUSH E AND SLOWLY WEAKEN. WHILE THE CONVECTIVE ACTIVITY SHOULD BECOME LESS OF AN ISSUE...A FAIR AMOUNT OF LOW-LEVEL MOISTURE WILL LIKELY LINGER IN THE VICINITY OF THE FRONT. WESTERN ATLANTIC... A STRONG COLD FRONT...ASSOCIATED WITH A RAPIDLY DEEPENING LOW PRES SYSTEM OVER THE MID-ATLANTIC STATES...IS PUSHING E ACROSS THE EXTREME WRN ATLC FROM THE CAROLINA COASTLINE ACROSS S FLORIDA/THE STRAITS AND INTO THE NW CARIB. A SWATH OF SHOWERS AND TSTMS ARE WITHIN 90-120 NM AHEAD OF THE FRONT. THE STRONGEST ACTIVITY IS IN THE NW CARIB...REFER TO THE CARIB SECTION FOR DETAILS. THE BIGGEST STORY IS PROBABLY THE STRONG WINDS BOTH AHEAD AND BEHIND THE FRONT. A GALE WARNING IS IN EFFECT N OF 27N FROM 75W TO THE FRONT FOR SLY WINDS IN THE 30-40 KT RANGE. THE W TO NW WINDS BEHIND THE FRONT ARE ALMOST AS STRONG...30-35 KT. THESE VERY BRISK WINDS ARE BUILDING HAZARDOUS SEAS IN THE AREA. THE REMAINDER OF THE REGION...W OF 60W...IS COVERED BY VERTICALLY STACKED RIDGING. THE MID/UPPER LEVEL RIDGE AXIS EXTENDS FROM A STRONG ANTICYCLONE IN THE CARIB NWD ALONG 21N72W 32N69W. THE SFC HIGH IS ANALYZED 1020 MB NEAR BERMUDA. BESIDES FOR DEBRIS CIRRUS BEING ADVECTED E BY THE UPPER WLYS...THE REGION IS FREE OF ORGANIZED CLOUD COVER. THE FRONT IS EXPECTED TO CONTINUE ITS RATHER QUICK EWD PROGRESSION OVER THE NEXT FEW DAYS. WINDS SHOULD REMAIN STRONG AHEAD AND BEHIND THE FRONT AS LOW PRES DEEPENS AND MOVES SLOWLY OFF THE MID-ATLANTIC COAST. CENTRAL AND EASTERN ATLANTIC... A VERTICALLY STACKED TROUGH/RIDGE PATTERN IS ESTABLISHED ACROSS THIS REGION. A 997 MB LOW PRES SYSTEM LOCATED WELL N OF THE AREA NEAR 41N44W HAS A WEAK DISSIPATING FRONT/REMNANT THAT ENTERS THE AREA NEAR 32N36W AND CONTINUES SW TO 21N56W. THIS BOUNDARY IS NOTHING MORE THAN A NARROW LINE OF LOW CLOUDS INDICATING A RATHER PRONOUNCED WIND SHIFT. THE UPPER AXIS IS HIGHLY ELONGATED EXTENDING ALONG 32N39W 20N55W 9N60W. THE ASSOCIATED DEEPEST MOISTURE...WHICH IS LIKELY IN THE FORM OF SCATTERED SHOWERS ARE MOSTLY CONTAINED W OF THE AXIS N OF 27N BETWEEN 50W-55W. FARTHER E...A MODEST RIDGE IS IN CONTROL. THE MID/UPPER AXIS RUNS FAIRLY N-S ALONG 29W WITH A PAIR OF SFC HIGHS BENEATH IT ANALYZED 1021 MB NEAR 31N28W AND 1020 MB NEAR 24N34W. THIS HIGH PRES...BOTH AT THE SFC AND ALOFT...IS ALLOWING FAIR WEATHER TO PREVAIL ACROSS NEARLY THE ENTIRE AREA. NWP MODELS SHOW THIS RIDGE FLATTENING OVER THE NEXT DAY OR TWO IN RESPONSE TO LOW PRES TO ITS W. $$ CANGIALOSI