000 AXNT20 KNHC 290542 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 105 AM EST WED NOV 29 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 0515 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N14W 6N30W 5N44W 4N53W. THE AXIS IS MORE ACTIVE TODAY THAN THE PAST COUPLE DAYS WITH SCATTERED MODERATE CONVECTION WITHIN 240 NM N AND 150 NM S OF THE AXIS BETWEEN 20W-48W. SOME OF THIS ACTIVITY MIGHT BE ASSOCIATED WITH A TROPICAL WAVE ALONG 40W...THIS WILL BE EXAMINED CLOSER AND IF NECESSARY WILL BE ADDED TO THE 0600 UTC MAP. ...DISCUSSION... THE GULF OF MEXICO... MAINLY FAIR WEATHER CONTINUES ACROSS THE GULF AS SFC HIGH PRES REMAINS IN CONTROL. BREEZY 15-20 KT ELY WINDS IN THE ERN AND CNTRL GULF IS ADVECTING PATCHES OF LOW-LEVEL CLOUDS AND EMBEDDED ISOLATED SHOWERS ACROSS CENTRAL AND SOUTH FLORIDA ON THE BREEZE. SOME OF THIS LOW-LEVEL MOISTURE IS BEING DRIVEN ACROSS THE GULF AND TOWARDS THE GULF COAST BY SELY RETURN FLOW AROUND THE 1028 MB SFC HIGH WHICH IS SLIDING E OFFSHORE OF THE MID-ATLANTIC STATES. IN THE UPPER LEVELS...A STRONG RIDGE IS ALSO SHIFTING E OF THE AREA...NOW CENTERED OVER SOUTH FLORIDA...IN RESPONSE TO A SHARP UPPER TROUGH OVER THE WRN U.S. WIDESPREAD STRONG SUBSIDENCE EXISTS EVERYWHERE ABOVE THE GULF. THIS STRONG CAP IS PREVENTING THE LOW-LAYER MOISTURE TO ACQUIRE MUCH DEPTH. GFS SHOWS THE SFC AND UPPER RIDGE CONTINUING ITS EASTWARD MOVEMENT AS THE UPPER TROUGH APPROACHES. TEMPS WILL REMAIN ABOVE NORMAL OVER THE NEXT DAY OR TWO BEFORE A COLD FRONT ENTERS THE AREA ON THU. GALE FORCE WINDS WILL ADVECT A MUCH COLDER AIRMASS INTO THE WRN AND CNTRL GULF BEHIND THE FRONT. GFS STALLS THE FRONT ON FRI ACROSS N FLORIDA AND EVENTUALLY A SHORTWAVE GIVES IT A PUSH ALLOWING IT TO MOVE ACROSS CNTRL AND S FLORIDA LATE THIS WEEKEND/EARLY NEXT WEEK. THE CARIBBEAN SEA... A WELL-DEFINED HIGHLY ELONGATED UPPER LEVEL TROUGH STRETCHES ACROSS PUERTO RICO SOUTHWESTWARD TOWARDS THE SOUTH AMERICAN COAST NEAR 15N76W. THE ASSOCIATED COLD FRONT HAS PULLED NE OF THE AREA. MULTILAYERED CLOUDINESS AND ISOLATED SHOWERS ARE LOCATED E OF THE UPPER TROUGH AXIS...MAINLY E OF 66W...WHICH INCLUDES THE LESSER ANTILLES. LOW-LEVEL CLOUDS AND ISOLATED SHOWERS EXIST ACROSS PUERTO RICO...AS DEPICTED ON SAN JUAN'S 88-D...AND LIKELY HISPANIOLA AND CUBA AS MODERATE NELY LOW-LEVEL FLOW ACROSS THE ATLC WATERS STIRS UP ENOUGH INSTABILITY. HOWEVER DUE TO THE VERY DRY STABLE UPPER LEVEL AIR ALOFT ACROSS MUCH OF THE CARIBBEAN ...W OF THE TROUGH AXIS...THE ACTIVITY IS STAYING SHALLOW. S-SWLY UPPER LEVEL FLOW IS DRAWING SOME MOISTURE FROM THE ITCZ AND SPARKING SCATTERED SHOWERS AND TSTMS S OF 14N W OF 73W. TRADE WINDS HAVE INCREASED A LITTLE THIS MORNING BUT REMAIN MODERATE. THESE WINDS WILL CONTINUE TO STRENGTHEN AS THE FRONTAL BOUNDARY IN THE ATLC PULLS AWAY AND HIGH PRES STRENGTHENS TIGHTENING THE PRES GRAD. THE ATLANTIC OCEAN... MODERATE TO STRONG HIGH PRES BOTH AT THE SFC AND ALOFT COVERS THE WRN ATLC. VERY DRY AIR ALOFT IS WIDESPREAD W OF 60W SUPPRESSING ANY DEEP CLOUDINESS. HOWEVER...BELOW THE SINKING INVERSION MODERATE NE-ELY FLOW IS GENERATING SMALL PATCHES OF LOW CLOUDS AND ISOLATED SHOWERS ACROSS THE SEA...SIMILAR TO THE CONDITIONS IN THE GULF AND NW CARIB. THE ONLY LOW PRES FEATURE IS IN THE CNTRL ATLC WHERE A COLD FRONT EXTENDS FROM AN OCCLUDED 994 MB LOW NEAR 38N37W ALONG 32N42W 24N48W 18N57W. SWLY UPPER LEVEL FLOW...ON THE E SIDE OF A HIGHLY ELONGATED MID/UPPER LEVEL TROUGH...AND LOW-LEVEL LIFT NEAR THE SFC BOUNDARY IS PRODUCING MULTILAYERED CLOUDS WITH EMBEDDED SCATTERED SHOWERS WITHIN 300 NM EITHER SIDE OF THE FRONT. MODELS SHOW THE SFC LOW QUICKLY RACING TO THE NE WHICH SHOULD HELP TO SLOWLY THIN THE MOISTURE PLUME IN THIS AREA OVER THE NEXT DAY OR TWO. AN ELONGATED RATHER HIGH AMPLITUDE MID/UPPER LEVEL RIDGE LIES E OF THE TROUGH AND COVERS THE AREA E OF 40W N OF 20N. SLIGHT UPPER LEVEL TROUGHING STILL EXISTS IN THE TROPICAL ATLC PROVIDING A FAVORABLE PATTERN FOR CONVECTION IN THE ITCZ. DEEP MOISTURE IS VERY LIMITED OUTSIDE OF THE ITCZ AND FRONTAL BOUNDARY/UPPER TROUGH. PLENTY OF DRY STABLE AIR ALOFT IS LOCATED E OF 30W S OF 25N ENHANCED BY UPPER LEVEL CONFLUENT FLOW W OF AN UPPER TROUGH OVER AFRICA. AT THE SFC...WEAK TO MODERATE HIGH PRES RIDGING IS THE RULE ACROSS THE ERN AND WRN SUBTROPICAL ATLC SUPPORTED BY A 1030 MB HIGH NE OF THE AZORES NEAR 40N16W AND A 1028 MB HIGH OFFSHORE OF THE MID-ATLANTIC U.S. A PRONOUNCED WEAKNESS IN THIS RIDGING LIES IN THE CNTRL ATLC DUE TO THE SFC LOW AND FRONTAL BOUNDARY MENTIONED. $$ CANGIALOSI