000 AXNT20 KNHC 251730 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST THU JAN 25 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 6N10W 3N28W 2N36W CROSSING THE EQUATOR AT 44W. ISOLATED MODERATE CONVECTION IS WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 25W-31W. ...DISCUSSION... GULF OF MEXICO... A COLD FRONT IS PRESSING S AND E ACROSS THE SRN GULF. AT 15Z...A WEAK 1014 MB LOW WAS ANALYZED IN S FLA WITH A COLD FRONT EXTENDING SW ALONG 24N86W 22N91W THEN STATIONARY TO S MEXICO NEAR 18N92W. THIS SFC ANALYSIS IS CONSIDERABLY DIFFERENT FROM THE PAST FEW WHICH INDICATED THAT THE COLD FRONT CLEARED THE YUCATAN PENINSULA. INDEED...A CLOUD LINE/WIND SHIFT IS CLEARLY SEEN AHEAD OF THE CURRENT PSN BUT BASED ON THIS MORNING OBS...IT APPEARS THAT IT IS BETTER REPRESENTED AS A PREFRONTAL TROUGH WHICH NOW EXTENDS FROM 24N83W SW INTO THE NW CARIB. DOPPLER RADAR SHOWS A SWATH OF SHOWERS AND TSTMS MOVING ACROSS EXTREME S FL AND THE KEYS. THICK CLOUDINESS AND ISOLATED SHOWERS EXIST BEHIND THE FRONT WITHIN 180 NM...WITH CLEARING BEHIND THAT ACROSS THE NRN GULF. MUCH COLDER AIR IS FILTERING SWD BEHIND THE FRONT WITH TEMPS IN THE 40'S AND LOW 50'S F ACROSS THE GULF COAST. STRONG NLY WINDS CONTINUE TO BLOW IN THE SW GULF WHERE A GALE WARNING IS IN EFFECT...REFER TO THE HIGH SEAS FORECAST UNDER HEADER MIAHSFAT2 FOR DETAILS. FARTHER W...A PERSISTENT FRONT REMAINS STATIONARY IN THE MEXICAN PLATEAU. THIS FRONT IS WELL DEFINED BY THE WRN EDGE OF LOW CLOUDINESS WHICH REMAINS BANKED IN THE REGION...ALTHOUGH IT IS NOW SHOWING SIGNS OF THINNING. THE COLD LOW-LEVEL AIR E OF THE FRONT HAS BEEN VERY IMPRESSIVE FOR MEXICO AND IN FACT 3 CM OF SNOW WAS REPORTED ON THE GROUND THIS MORNING IN CHIHUAHUA. CARIBBEAN SEA... MOST OF THE CARIBBEAN IS IN A VERY STABLE REGIME AS A MID TO UPPER LEVEL RIDGE REMAINS ANCHORED ACROSS THE REGION. ABUNDANT DRY AIR/SUBSIDENCE IS SUPPRESSING CONVECTIVE ACTIVITY...ALTHOUGH A FEW SMALL CLUSTERS LOCATED OVER W COLOMBIA AND S OF PANAMA MAY HOLD TOGETHER AS THEY ARE DRAWN NWD BY THE SLY BRANCH OF THE BROAD RIDGE. A SLIGHT CHANGE IN THE PATTERN IS BEGINNING TO AFFECT THE NW CARIB AS A PREFRONTAL TROUGH AND COLD FRONT MOVE ACROSS THE NW PORTION. AS OF 15Z...THE PREFRONTAL TROF WAS ANALYZED FROM THE SE GULF ACROSS W CUBA TO THE NW COAST OF HONDURAS. LIKE MOST FRONTS IN THE CARIB...THIS ONE IS EXPECTED TO WEAKEN BUT IT WILL BE DEFINED ENOUGH TO TURN THE FLOW NLY ADVECTING IN SOME COOLER WEATHER FOR THE NW CORNER OVER THE NEXT DAY OR TWO. ELSEWHERE EASTERLY TRADES ARE MAINLY IN THE 15-25 KT RANGE...STRONGEST N OF THE COLOMBIAN COAST...WHICH IS TYPICAL DUE TO THE LOWER PRES OVER COLOMBIA. BROKEN PATCHES OF LOW LEVEL MOISTURE ARE DRIVEN W BY THE TRADES IN THE ERN CARIB AND THEN STEERED TO THE N-NE AHEAD OF THE PREFRONTAL TROF ACROSS JAMAICA...THE CAYMAN ISLANDS AND CUBA. ATLANTIC OCEAN... A FRONTAL SYSTEM HAS BECOME MORE DEFINED IN THE W ATLC. AS OF 15 UTC...A 1010 MB LOW IS LOCATED NEAR 30N71W WITH A COLD FRONT EXTENDING SW TO THE BAHAMAS NEAR 27N78W. THE FRONT THEN BECOMES STATIONARY TO S FLA CONNECTING TO A 1014 MB LOW...OR FRONTAL WAVE. DENSE CLOUDINESS AND STRATIFORM PRECIP IS WIDESPREAD N OF THE BOUNDARY. MORE CONVECTIVE WEATHER IS ALONG THE FRONT...MAINLY IN THE SE GULF. GFS SHOWS THE LOW NEAR 30N MOVING TO THE NE AND BECOMING ABSORBED BY A LARGER LOW TO THE NW...CREATING A VERY LARGE STRONG STORM SYSTEM IN THE N ATLC TOMORROW. ALOFT...THE STRONG RIDGE CENTERED IN THE CARIB COVERS MOST OF THE AREA W OF 50W. A SUBTROPICAL JET...WITH CORE WINDS NEAR 150 KT...IS RIDING ALONG THE N PERIPHERY OF THE RIDGE SPREADING A LARGE SWATH OF MOISTURE ACROSS THE AREA N OF 27N. WIDESPREAD DRY AIR EXISTS S OF THERE. MUCH OF THIS MOISTURE THEN CURVES AROUND THE BASE OF A HIGHLY ELONGATED UPPER TROUGH NEAR 32N34W. THIS UPPER TROUGH SUPPORTS A WEAKENING FRONTAL BOUNDARY WHICH WAS ANALYZED STATIONARY AT 12Z...BUT NOW DOES APPEAR TO BE SLOWLY MOVING ALONG 32N41W 26N50W 24N60W. FARTHER E...A WEAK 1014 MB LOW IS LOCATED JUST N OF THE CANARY ISLANDS WITH A COLD FRONT EXTENDING SW ALONG 25N17W 23N THEN BACK N AS A WARM FRONT TO 30N32W. WEAK SFC RIDGING LIES TO THE S OF THE FRONTS MENTIONED...A 1020 MB HIGH IS CENTERED NEAR 20N30W...A 1018 MB NEAR 18N58W AND A 1017 MB NEAR 23N66W. THE WEAK RIDGING ALONG WITH LARGE FRONTAL BOUNDARIES HAVE CREATED A WEAK SFC PATTERN ACROSS MUCH OF THE ATLC. $$ CANGIALOSI