000 AXNT20 KNHC 072304 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN JAN 07 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 ALONG 2N AT THE PRIME MERIDIAN...2N20W 1N30W CROSSING THE EQUATOR AT 39W INTO NORTHEASTERN BRAZIL AT 2S45W. SCATTERED MODERATE CONVECTION IS FROM 3N-5N BETWEEN 31W-37W AND FROM 2S-3S BETWEEN 33W-36W. ...DISCUSSION... THE GULF OF MEXICO... THE FRONTAL BOUNDARY...WHICH WAS STATIONARY YESTERDAY AT THIS TIME...HAS BEEN ON THE MOVE OVER THE PAST 18 HOURS AS ITS UPPER LEVEL SUPPORT HAS NEARED THE SFC BOUNDARY. AS OF 21 UTC...THE COLD FRONT WAS ANALYZED FROM THE MS/LA BORDER TO S MEXICO ALONG 30N89W 24N94W 20N97W. DOPPLER RADAR DEPICTS A LINE OF SHOWERS AND TSTMS WITHIN 60 NM AHEAD OF THE FRONT N OF 28N WITH THE STRONGEST ACTIVITY OVER LAND...MOSTLY IN ALABAMA...WHERE INSTABILITY IS GREATER. SINCE THERE IS NOT MUCH RADAR COVERAGE S OF 28N...IT IS DIFFICULT TO TELL IF CONDITIONS ARE SIMILAR BUT BASED ON THE UNIFORMITY OF CLOUD TOPS IN IR IMAGERY IT IS ASSUMED TO BE SO...AT LEAST N OF 25N. MUCH OF THE CENTRAL AND E GULF AHEAD OF THE FRONT IS EXPERIENCING CONTINUED UNSEASONABLY WARM AND HUMID WEATHER UNDER 10 TO 20 KT S-SE FLOW AND DRY STABLE AIR SUPPORTED BY A STRONG MID TO UPPER LEVEL RIDGE EXTENDING NWD FROM THE W CARIB. BEHIND THE FRONT...CLOUDS AND ISOLATED SHOWERS ARE LINGERING WITHIN 200 NM. STRONG NLY WINDS ARE USHERING IN A MORE SEASONABLE AIRMASS WITH TEMPS FALLING THRU THE 60'S F AND QUICKLY FALLING DEW POINTS TOWARD THE 30'S F IN SE TX. THESE NLY WINDS WILL INCREASE TONIGHT WITH GUSTS TO GALE FORCE IN THE SW GULF AS SFC HIGH PRES MOVES SE TIGHTENING THE PRES GRAD. THE COLD FRONT WILL CONTINUE TO MOVE TO THE SE CLEARING THE ENTIRE AREA BY LATE TUE SPREADING THE COOLER MORE SEASONABLE AIRMASS EWD. THE CARIBBEAN SEA... A PRONOUNCED UPPER LEVEL RIDGE/TROUGH PATTERN HAS SET UP. THE RIDGE COVERS THE REGION W OF 77W WITH THE BASE OF A SHARP CENTRAL ATLC TROUGH DOMINATING THE REST OF THE CARIB. THIS UPPER LEVEL PATTERN IS HELPING TO FURTHER SINK AND DRY THE AIR IN THE MID AND UPPER LEVELS. THE STABLE AIR COVERS THE ENTIRE AREA...WITH THE DRIEST AIR IN THE STRONGEST CONFLUENT ZONE BETWEEN 72W-80W. TRADE WINDS ARE ON THE STRONG SIDE GENERALLY BETWEEN 20-30 KT. THESE STIFF WINDS ARE STIRRING UP ENOUGH INSTABILITY TO GENERATE AND STEER PATCHES OF LOW-LEVEL MOISTURE WITH POSSIBLE ISOLATED SHOWERS ACROSS THE SEA AND PORTIONS OF CENTRAL AMERICA. THE TRADES WILL BEGIN TO RELAX TOMORROW AND TUE AS HIGH PRES N OF THE AREA SHIFTS E IN RESPONSE TO A FAST MOVING LOW PRES TROUGH CURRENTLY ACROSS THE OHIO VALLEY. THE UPPER LEVEL FLOW WILL GRADUALLY BECOME MORE ZONAL OVER THE NEXT COUPLE OF DAYS. THIS WILL LIKELY HELP MOISTEN THE ATMOSPHERE SOME...BUT MODELS ARE NOT SUGGESTING MUCH IN THE WAY OF DEEP MOISTURE THRU TUE. THE ATLANTIC OCEAN... A BROAD SFC HIGH PRES RIDGE COVERS MUCH OF THE ATLC BASIN WITH TWO CORES ANALYZED...A 1025 MB JUST E OF BERMUDA NEAR 31N63W AND A 1033 MB S OF THE AZORES NEAR 35N23W. HOWEVER...A SFC TROUGH ALIGNED NE-SW FROM 15N57W TO 26N51W IS INTERRUPTING THE STRONG RIDGE. THIS SFC FEATURE IS A REFLECTION OF A WELL-DEFINED UPPER LEVEL TROUGH WITH TWO EMBEDDED CYCLONIC CIRCULATIONS COVERING THE AREA BETWEEN 48W-66W. SCATTERED SHOWERS ARE LIKELY OCCURRING FROM 22N-25N BETWEEN 48W-56W. GFS HAS HAD A GOOD HANDLE ON THE EVOLUTION OF THIS SYSTEM OVER THE PAST DAY OR TWO AND ITS CURRENT SOLUTION SHOWS THE UPPER LEVEL LOW CUTTING OFF...WEAKENING AND BECOMING ABSORBED BY A MUCH LARGER TROUGH OVER THE NEXT FEW DAYS. THIS WILL LIKELY DRIVE THE ASSOCIATED MOISTURE NWD. THE WRN ATLC IS DOMINATED BY NLY UPPER LEVEL FLOW ON THE E SIDE OF A RIDGE IN THE W CARIB AND SE GULF. THIS DRY FLOW IS PRODUCING STABLE CONDITIONS ACROSS THE REGION... BASICALLY W OF 58W. THE ERN ATLC LIES ON THE N SIDE OF A VERY BROAD UPPER LEVEL RIDGE CENTERED ROUGHLY NEAR 7N35W. WLY FLOW AND PATCHES OF MID AND HIGH LEVEL CLOUDS AND EMBEDDED ISOLATED SHOWERS DOT THE AREA. THE THICKEST CLOUDS ARE FROM 6N-20N BETWEEN 37W-60W. THIS IS THE AREA OF HIGHEST UPPER LEVEL DIFFLUENCE BETWEEN THE RIDGE TO THE SE AND THE CENTRAL ATLC TROUGH TO THE NW. THIS DIFFLUENT PATTERN IS ALSO ENHANCING SCATTERED MODERATE CONVECTION N OF THE ITCZ FROM 4N-8N BETWEEN 32W-45W. $$ CANGIALOSI