000 AXNT20 KNHC 032320 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST SUN DEC 03 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... METEOROLOGICAL ANALYSIS...WEATHER OBSERVATIONS...AND RADAR. BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 7N10W 5N25W 5N35W 5N45W 5N53W. THE ITCZ IS FAIRLY QUIET WITH ONLY A FEW AREAS OF CONVECTION. SCATTERED MODERATE IS FROM 3N-8N BETWEEN 34W-43W. ISOLATED MODERATE IS FROM 1N-4N E OF 13W. ...DISCUSSION... GULF OF MEXICO... A STRONG MID/UPPER LEVEL RIDGE REMAINS PARKED IN THE NW CARIBBEAN. THIS LEAVES THE GULF UNDER A MOIST SWLY UPPER LEVEL FLOW REGIME PRODUCING CONSIDERABLE MID-HIGH LEVEL CLOUDINESS. AT THE SFC...A FRONTAL BOUNDARY IS STATIONARY FROM N CENTRAL FLORIDA INTO THE BAY OF CAMPECHE ALONG 29N83W 25N88W 19N93W. LOW-LEVEL LIFT ALONG WITH UPPER LEVEL MOISTURE IN PLACE IS GENERATING ISOLATED TO SCATTERED SHOWERS WITHIN 180 NM EITHER SIDE OF THE SFC BOUNDARY. STRONG HIGH PRES IS BUILDING SWD BEHIND THE FRONT ANALYZED AT AN IMPRESSIVE 1044 MB IN NRN KANSAS. THE TIGHT PRES GRAD BETWEEN THE STRONG HIGH AND THE FRONT IS GENERATING STRONG N-NE WINDS W OF THE FRONT ADVECTING MUCH COOLER AND DRIER AIR. THESE NLY WINDS ARE NOW MAINLY IN THE 20-30 KT RANGE BUT ARE STRONGER IN THE SW GULF WHERE A GALE WARNING IS IN EFFECT. THIS STRONG FLOW IS POOLING AND BANKING THICK LOW-LEVEL CLOUDS AND DRIZZLE E OF THE SLOPES OF THE SIERRA MADRE IN MEXICO. BECAUSE OF THIS THICK CLOUDINESS AND A TEMP GRAD NOTED A STATIONARY FRONT WAS ADDED TO THE 21Z MAP ALONG THE E SLOPES. AS A SHORTWAVE TROUGH...CURRENTLY ACROSS THE PLAINS...MOVES E IT WILL ERODE THE STRONG UPPER HIGH IN THE CARIB AND FORCE THE SFC FRONT SWD DOWN THE FLORIDA PENINSULA OVER THE NEXT DAY OR TWO. THE STRONG SFC HIGH WILL ALSO MOVE E KEEPING WINDS STRONG...ESPECIALLY IN THE SW GULF...OVER THE NEXT COUPLE DAYS. CARIBBEAN SEA... A LARGE STRONG MID/UPPER LEVEL HIGH CENTERED IN THE NW CARIBBEAN NEAR THE CAYMAN ISLANDS COVERS THE REGION W OF 65W. VERY DRY AIR ALOFT EXISTS EVERYWHERE PROVIDING A STRONG MID-LEVEL CAP NOT ALLOWING ANY OF THE TYPICAL TRADE WIND SHOWERS ACQUIRE MUCH DEPTH. A LARGE UPPER LEVEL LOW IS MOVING W CENTERED NE OF THE LEEWARD ISLANDS NEAR 19N59W. THE LESSER ANTILLES IS ON THE DRY W SIDE OF THE SYSTEM WHICH IS KEEPING CONDITIONS QUIET. HOWEVER...AS THE UPPER LOW/SFC TROUGH MOVES W INTO THE ERN CARIB OVER THE NEXT COUPLE DAYS SOME SHOWER AND TSTM ACTIVITY WILL LIKELY SPREAD INTO THE AREA. AT THE SFC...MODERATE TO STRONG HIGH PRES TO THE N ALONG WITH THE LOW PRES TROUGH TO THE E IS PRODUCING TRADE WINDS IN THE 20-25 KT RANGE ACROSS MUCH OF THE AREA. THE COMBINATION OF THESE STRONG WINDS AND NE SWELL IS GENERATING HAZARDOUS MARINE CONDITIONS. SFC WINDS WILL INCREASE IN THE NW CARIB AS THE STRONG HIGH OVER THE U.S. SRN PLAINS MOVES E. ELSEWHERE THE WINDS WILL GRADUALLY SUBSIDE AS THE PRES GRAD WEAKENS. THE ATLANTIC OCEAN... AN AMPLIFIED RIDGE/TROUGH/RIDGE PATTERN DOMINATES MUCH OF THE SUBTROPICAL AND TROPICAL ATLC. A STRONG BROAD MID/UPPER LEVEL RIDGE CENTERED IN THE NW CARIBBEAN HAS RIDGING THAT EXTENDS NEWARD TO BERMUDA. A LARGE UPPER LEVEL LOW CENTERED NE OF THE LEEWARD ISLANDS NEAR 19N59W HAS CARVED OUT A PRONOUNCED WEAKNESS IN THE RIDGING. THIS LOW HAS ITS HIGHEST MAGNITUDE AT UPPER LEVELS BUT IT DOES HAVE A CLEAR SFC SIGNATURE WITH WINDS VEERING IN SHIPS REPORTS AND AN EARLIER QSCAT PASS...ANALYZED AS A SFC TROF ALONG 57W FROM 10N-24N. SCATTERED SHOWERS AND TSTMS ARE LOCATED ON THE MOIST E SIDE OF THE UPPER LOW FROM 11N-23N BETWEEN 50W-60W. THERE IS A SMALL WEAK UPPER LOW AND POSSIBLY A RELATED SFC TROUGH NE OF THE MAIN ONE NEAR 29N48W GENERATING ISOLATED SHOWERS WITHIN 120 NM E OF THE ILL-DEFINED CENTER. DRY AIR ALOFT COVERS THE AREA W OF THE UPPER LOW NEAR THE LEEWARD ISLANDS...WHICH INCLUDES ALL OF THE WRN ATLC...WITH THE EXCEPTION OF THE NW CORNER JUST E OF THE N CENTRAL FLORIDA WHERE THERE IS FORCING NEAR A FRONTAL BOUNDARY. AN UPPER LEVEL RIDGE LIES IMMEDIATELY E OF THE UPPER LOW WITH THE RIDGE AXIS ROUGHLY ALONG 40W CONTAINED S OF 25N EXTENDING DEEP INTO THE TROPICS. SW-WLY WINDS AROUND THIS RIDGE HAS ADVECTED DEBRIS UPPER LEVEL MOISTURE FROM THE SHOWERS AND TSTMS IN THE CENTRAL ATLC ASSOCIATED WITH THE UPPER LOW. BROKEN TO OVERCAST MID-HIGH LEVEL CLOUDINESS AND SCATTERED SHOWERS LIKELY EXISTS BETWEEN THE MAIN UPPER LOW MENTIONED AND 30W S OF 28N. THE ERN MOST ATLC IS UNDER A HIGHLY ELONGATED INVERTED TROUGH. AT THE SURFACE...MODERATE TO STRONG HIGH PRES RIDGING DOMINATES THE ATLC. THIS RIDGING IS BLEMISHED A BIT BY THE SFC TROUGH IN THE CNTRL CARIB. THE FAIRLY TIGHT PRES GRAD IS GENERATING A LARGE AREA OF STIFF NE-E WINDS AND HIGH SEAS. $$ CANGIALOSI