000 AXNT20 KNHC 281736 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 PM EST WED NOV 28 2007 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 5N15W 6N30W 4N47W 2N51W. SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM EITHER SIDE OF THE AXIS BETWEEN 17W-38W. DISCUSSION... GULF OF MEXICO... STALLED FRONTAL BOUNDARY HAS BECOME DIFFUSE ACROSS THE SE GULF...FROM S FLORIDA TO JUST N OF THE YUCATAN PENINSULA NEAR 22N90W...AS ITS UPPER SUPPORT PULLS AWAY. IN AGREEMENT...TEMPS AND WINDS ACROSS THE REGION ARE MORE UNIFORM AS COMPARED TO YESTERDAY AT THIS TIME. VISIBLE IMAGERY SHOWS PATCHY LOW TO MID LEVEL CLOUDS WHICH COULD CONTAIN ISOLATED SHOWERS WITHIN 90 NM OF THE FRONT. SLIGHTLY THICKER CLOUDINESS IS IN THE BAY OF CAMPECHE S OF 21N W OF 93W POSSIBLY ENHANCED BY SOMEWHAT DIFFLUENT FLOW ALOFT. FAIRLY TRANQUIL CONDITIONS ARE THE RULE ELSEWHERE UNDER THE INFLUENCE OF A MID-UPPER RIDGE DIRECTLY OVERHEAD AND SFC HIGH PRES EXTENDING SW FROM THE MID-ATLANTIC/NORTHEAST. THE MOST STABLE ENVIRONMENT IS OVER THE NE GULF IN AN UPPER CONFLUENT AREA NEAR A SHORTWAVE IN THE W ATLC. CARIBBEAN SEA... THE ENTIRE CARIBBEAN IS RATHER QUIET TODAY...WHICH IS QUITE A CHANGE FROM THE PAST DAY OR SO FOR THE SW CARIB. A MID TO UPPER RIDGE HAS SHIFTED SWD SLIGHTLY CENTERED NEAR JAMAICA AND MUCH OF THE E CARIB LIES ON THE W END OF A LARGE CUT OFF IN THE CENTRAL ATLC. THIS HAS ALLOWED VERY DRY AND STABLE MID-UPPER AIR TO POUR INTO THE ERN HALF OF THE REGION WHILE THIN PATCHY HIGH LEVEL CLOUDINESS LIES OVER THE SW PORTION. AT THE SFC...NE TO E TRADES ARE STILL ON THE STRONG SIDE...AROUND 25 KT NEAR THE COAST OF COLOMBIA AS NOTED IN AN 11Z QSCAT PASS. THESE BRISK WINDS ARE CARRYING STREAMS OF LOW-LEVEL MOISTURE...BENEATH THE MID-LEVEL CAP...WHICH CONTAIN ISOLATED QUICK MOVING SHOWERS AS REVEALED IN SAN JUAN'S DOPPLER RADAR. THE BEST CHANCE FOR THESE SHALLOW SHOWERS IS OVER THE NE CARIB CLOSER TO THE ATLC WATERS. ATLANTIC OCEAN... A WEAKENING FRONT CUTS ACROSS THE NW PORTION OF THE AREA MAINLY STATIONARY FROM 32N70W TO SOUTH CENTRAL FLORIDA. DOPPLER RADAR IS DETECTING ISOLATED TO SCATTERED SHOWER ACTIVITY ALONG THE E COAST OF FLA ROUGHLY BETWEEN PALM BEACH AND DAYTONA BEACH OUT INTO THE NW BAHAMAS. SIMILAR ACTIVITY IS LIKELY OCCURRING ELSEWHERE WITHIN 60 NM OF THE FRONT. A LARGE WELL DEFINED MID TO UPPER CUT OFF LOW IS SITUATED IN THE CENTRAL ATLC NEAR 23N55W. A LOW-LEVEL TROUGH IS LOCATED BENEATH THE CUT OFF ALONG 50W/51W FROM 16N-30N. WHILE QSCAT DATA SHOWS LITTLE DIRECTIONAL CHANGE IN THE SFC WINDS THERE IS EASILY A 5 KT INCREASE IN SPEED NEAR THE TROUGH AND A WELL DEFINED KINK IN THE ISOBARIC PATTERN. THE COMBINATION OF THE UPPER LOW AND LOW-LEVEL BOUNDARY IS PRODUCING SCATTERED SHOWERS AND TSTMS FROM 17N-28N BETWEEN 47W-56W...WITH A BIT MORE CONCENTRATION NEAR THE UPPER LOW CENTER. ISOLATED SHOWERS LIE FURTHER E IN AN UPPER DIFFLUENT AREA FROM 21N-27N BETWEEN 37W-47W. THE REMAINDER OF THE AREA W OF 56W IS TRANQUIL UNDER A FAIRLY DRY MID-UPPER ENVIRONMENT ASSOCIATED WITH ELONGATED RIDGING. UNINTERRUPTED STRONG SFC RIDGING DOMINATES THE TROPICAL AND SUBTROPICAL E ATLC EXTENDING SW FROM A HEALTHY 1036 MB HIGH JUST W OF THE AZORES NEAR 39N36W. THIS IS ALLOWING MODERATE TO STRONG ELY TRADES TO CONTINUE ACROSS THE REGION...STRONGEST NEAR THE COAST OF AFRICA WHICH IS TYPICAL BECAUSE OF THE TIGHTENED GRADIENT BETWEEN THE HIGH AND LOW PRES OVER THE CONTINENT. THE MID AND UPPER FLOW IS FAIRLY ZONAL AND QUITE STRONG ESPECIALLY FROM 10N-20N. THIS FLOW IS ADVECTING PATCHY HIGH LEVEL CLOUDS...BUT NOT MUCH SENSIBLE WEATHER. $$ CANGIALOSI