000 AXNT20 KNHC 271119 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 AM EST MON NOV 27 2006 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1100 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 8N13W 5N30W 4N47W 3N53W. SCATTERED MODERATE CONVECTION IS WITHIN 120 NM N AND 180 NM S OF THE AXIS E OF 22W. THE REMAINDER OF THE AXIS IS RATHER QUIET WITH ONLY ONE AREA OF SCATTERED MODERATE WITHIN 60 NM EITHER SIDE BETWEEN 32W-35W. ...DISCUSSION... THE GULF OF MEXICO... THE WEATHER ACROSS THE GULF REMAINS FAIRLY UNEVENTFUL AS SFC HIGH PRES CONTINUES TO DOMINATE THE AREA. BREEZY 15-20 KT NE TO E WINDS IN THE ERN AND CNTRL GULF IS ADVECTING SOME LOW-LEVEL CLOUDS AND ISOLATED SHOWERS ACROSS CENTRAL AND SOUTH FLORIDA ON THE BREEZE WITH SOME BROKEN CLOUDS PUSHING W ACROSS THE GULF WATERS. HOWEVER...BECAUSE OF THE WIDESPREAD STRONG SUBSIDENCE ABOVE THE LOW-LAYER OF MOISTURE THERE IS LIMITED DEPTH TO THE CLOUDS. THE SFC FLOW IS A LITTLE LIGHTER AND IS MORE ESELY IN THE WRN GULF FLOWING CLOCKWISE AROUND THE 1028 MB SFC HIGH CENTERED IN NE GEORGIA. IN THE UPPER LEVELS...A PRONOUNCED RIDGE CENTERED IN THE SW GULF HAS RIDGING THAT EXTENDS ACROSS THE CENTRAL GULF AND INTO THE OHIO VALLEY. SLIGHT UPPER TROUGHING IS LIFTING OUT BUT STILL LIES ABOVE SE FLORIDA. GFS SHOWS THE UPPER AND SFC RIDGE BUILDING E. THIS WILL ALLOW TEMPS TO REMAIN SLIGHTLY ABOVE NORMAL VALUES OVER THE NEXT FEW DAYS. THE NEXT AIRMASS CHANGE IS ANTICIPATED TO AFFECT THE AREA LATE IN THE WEEK AS A POTENTIAL STRONG COLD FRONT APPROACHES THE NW PORTION ON THU. GALE CONDITIONS ARE FORECAST BEHIND THE FRONT AS STRONG HIGH PRES BUILDS IN. THE CARIBBEAN SEA... THE UNSETTLED WEATHER THAT HAS BEEN IN THE SW CARIBBEAN OVER THE PAST SEVERAL DAYS...ASSOCIATED WITH A NEARLY STATIONARY SFC LOW PRES TROUGH ALONG 77W FROM 10N-16N...HAS DIMINISHED. THE FEATURE IS STILL EVIDENT...BARELY...BUT IS NOW VERY SHALLOW WITH ONLY LOW TO MID-LEVEL CLOUDS VEERING ABOUT THE AXIS. THE TAIL END OF A SLOWLY WEAKENING STATIONARY FRONT EXTENDS ACROSS THE WINDWARD PASSAGE TO JUST W OF JAMAICA NEAR 17N76W. DEEP MOISTURE IS VERY LIMITED ALONG THE FRONT WITH ONLY ISOLATED SHOWERS WITHIN 120 NM OF THE SFC BOUNDARY. S-SWLY UPPER LEVEL FLOW...ASSOCIATED WITH A VERY BROAD FLAT RIDGE CENTERED OVER VENEZUELA...IS DRAWING SOME MOISTURE FROM THE ITCZ AND SPREADING IT ABOVE THE SFC FRONT INTO THE ATLC. HOWEVER...AS MENTIONED...THE MOISTURE PLUME IS SIGNIFICANTLY THINNER THAN IT HAS BEEN WITH ONLY BROKEN MID-HIGH LEVEL CLOUDINESS AND EMBEDDED ISOLATED SHOWERS NOTED BETWEEN 72W-83W. VERY DRY AIR/STRONG SUBSIDENCE LIES ABOVE THE ERN AND THE EXTREME WRN CARIB SUPPRESSING ANY DEEP CLOUDINESS. TRADES ARE MODERATE AND WILL LIKELY REMAIN THAT WAY OVER THE NEXT COUPLE DAYS. LATER THIS WEEK...THESE WINDS WILL LIKELY INCREASE AS THE FRONTAL BOUNDARY PULLS NE AND STRONG HIGH PRES DEVELOPS TO THE N TIGHTENING THE PRES GRAD. THE ATLANTIC OCEAN... WEAK UPPER TROUGHING...VERY DRY AIR ALOFT AND PATCHES OF LOW-LEVEL MOISTURE UNDERNEATH THE STRONG MID-LEVEL CAP COVERS THE AREA W OF A PERSISTENT FRONTAL BOUNDARY IN THE CNTRL/WRN ATLC. THE FRONT IS ASSOCIATED WITH AN OCCLUDED 1012 MB LOW NEAR 33N56W AND IS PROGRESSIVE...COLD FRONT...FROM A TRIPLE POINT NEAR 33N53 SOUTHWESTWARD TO 25N60W THEN STATIONARY TO THE WINDWARD PASSAGE. MULTILAYERED CLOUDS WITH EMBEDDED SCATTERED SHOWERS ARE ASSOCIATED WITH THE WEAK LOW/FRONTAL BOUNDARY AND EXTEND WITHIN 300 NM E OF THE FRONT N OF 27N AND WITHIN 150 NM EITHER SIDE S OF 27N. A SHORTWAVE UPPER TROUGH STRETCHES FROM 32N26W 23N40W TO AN UPPER LOW IN THE DEEP TROPICS NEAR 9N53W. ELONGATED RIDGING LIES E OF THE SHORTWAVE AND COVERS THE REMAINDER OF THE E ATLC. THIS UPPER LEVEL PATTERN IN THE E ATLC HAS SIGNIFICANTLY FLATTENED TODAY AS THE NRN EXTENSION OF THE SHORTWAVE TROUGH HAS HELPED TO BREAK DOWN THE ONCE AMPLIFIED UPPER LEVEL RIDGE. AN UPPER LEVEL HIGH IS LOCATED IN THE TROPICAL ATLC E OF THE UPPER LOW NEAR 7N37W. UPPER LEVEL DIFFLUENCE BETWEEN THE UPPER LOW AND HIGH IS GENERATING ISOLATED SHOWERS FROM 12N-16N BETWEEN 37W-43W...BUT THIS ACTIVITY IS MUCH WEAKER THAN IT HAS BEEN THE PAST FEW DAYS DUE TO THE FLATTENING PATTERN. PLENTY OF DRY STABLE AIR ALOFT IS LOCATED E OF 30W ENHANCED BY UPPER LEVEL CONFLUENT FLOW W OF AN UPPER TROUGH OVER AFRICA. SWLY UPPER LEVEL FLOW IS ENHANCING CONVECTION IN THE ITCZ E OF 22W. AT THE SFC...WEAK TO MODERATE HIGH PRES RIDGING IS THE RULE ACROSS THE SUBTROPICAL ATLC SUPPORTED BY A 1022 MB HIGH NEAR 29N25W. THIS RIDGING IS INTERRUPTED BY THE BOUNDARY/FRONTAL LOW MENTIONED IN THE CNTRL ATLC. $$ CANGIALOSI