000 AXNT20 KNHC 172353 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST FRI NOV 17 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A TROPICAL WAVE ALONG 52W S OF 21N IS NEARLY STATIONARY AS IT APPROACHES A LARGE CUT OFF LOW CENTERED NEAR 25N57W. STRONG SWLY UPPER LEVEL WINDS...ASSOCIATED WITH THIS CUT OFF LOW..IS SHEARING ALL OF THE DEEP CLOUDINESS AND SHOWER ACTIVITY WELL TO THE E/NE OF THE WAVE EXPOSING A SMALL ELONGATED LOW-LEVEL CLOUD SWIRL ALONG THE AXIS NEAR 17N. SHOWERS AND TSTMS EXTEND FROM 12N-21N BETWEEN 46W-51W. THE UPPER LOW/WAVE INTERACTION IS GENERATING MORE ACTIVITY FARTHER N...REFER TO THE ATLC DISCUSSION FOR MORE DETAILS. THIS WAVE WILL BEGIN TO MOVE W AGAIN AS IT BECOMES INCREASINGLY SHALLOW AND IS STEERED BY THE LOW-LEVEL FLOW. A TROPICAL WAVE IS IN THE CENTRAL CARIBBEAN ALONG 70W S OF 20N MOVING W 10 TO 15 KT. THIS WAVE IS VERY WEAK WITH ONLY A HINT OF SOME CYCLONIC TURNING IN THE LOW-LEVEL CLOUDS. NO ORGANIZED CLOUDINESS OR SHOWER ACTIVITY IS ASSOCIATED WITH THIS WAVE. ...THE ITCZ... THE ITCZ AXIS IS CENTERED ALONG 11N15W 6N31W 6N51W 7N58W. ISOLATED MODERATE IS WITHIN 180 NM EITHER SIDE OF THE AXIS BETWEEN 25W-34W AND WITHIN 150 NM N OF THE AXIS BETWEEN 42W-48W. ...DISCUSSION... THE GULF OF MEXICO... PLENTY OF DRY STABLE AIR ALOFT ALONG WITH SFC HIGH PRES IS PRODUCING FAIR AND PLEASANTLY COOL/DRY CONDITIONS WITH LIGHT LOW-LEVEL WINDS ACROSS NEARLY THE ENTIRE GULF. HOWEVER...THE EXTREME SRN GULF HAS NOT COMPLETELY CLEARED OUT AS A PLUME OF MOISTURE IS ADVECTED ENE...FROM WEAKENING T.S. SERGIO AND THE ITCZ IN THE EPAC...ACROSS SRN MEXICO TO EXTREME S FLORIDA. MOST OF THIS MOISTURE IS MAINLY IN THE FORM OF MID-HIGH LEVEL CLOUDINESS ALTHOUGH DOPPLER RADAR IS INDICATING SOME SHOWER ACTIVITY IN THE FL STRAITS. THIS MOISTURE IS SLOWLY SEEPING SE AND WILL LIKELY CLEAR THE AREA BY EARLY TOMORROW. FAIR AND COOL CONDITIONS ARE EXPECTED TO CONTINUE THIS WEEKEND AS STABLE AIR ALOFT REMAINS IN PLACE AND STRONG SFC HIGH PRES BUILDS INTO THE CNTRL U.S. THE BUILDING OF THIS STRONG RIDGE WILL LIKELY INCREASE THE WINDS/SEAS IN THE GULF THIS WEEKEND AND ESPECIALLY EARLY NEXT WEEK. THE CARIBBEAN SEA... THE TAIL END OF AN ATLC FRONTAL BOUNDARY HAS BECOME STATIONARY FROM CENTRAL CUBA TO THE NW COAST OF HONDURAS. LOW-LEVEL LIFT NEAR THE BOUNDARY ALONG WITH UPPER DIFFLUENCE BETWEEN AN UPPER HIGH NEAR 13N83W AND THE BASE OF THE TROUGH IN THE GULF IS PRODUCING A FAIR AMOUNT OF MOISTURE IN THE WRN CARIBBEAN. SCATTERED SHOWERS AND TSTMS ARE EMBEDDED IN THIS MOISTURE FROM 16N-21N BETWEEN 81W-86W AND IN THE SW CARIBBEAN FROM 12N-16N BETWEEN 77W-83W. THE CENTRAL AND ERN CARIBBEAN IS QUIET WITH STABLE AIR ALOFT...ESPECIALLY THE ERN CARIB...ON THE TYPICAL DRY W SIDE OF THE UPPER LOW IN THE CENTRAL ATLC. THIS STABLE AIR IS SUPPRESSING ANY SIGNIFICANT CONVECTION FROM FORMING. TRADE WINDS ARE LIGHT ACROSS THE AREA...EXCEPT FOR STRONGER 15-20 KT N TO NE WINDS BEHIND THE FRONT. NO BIG CHANGES ARE EXPECTED TOMORROW. THEREAFTER WINDS AND SEAS ARE LIKELY TO INCREASE IN THE W CARIB IN RESPONSE TO A REINFORCING COLD FRONT MOVING THROUGH THE GULF OF MEXICO AND STRONG SFC HIGH PRES BEHIND IT. THE ATLANTIC OCEAN... A LARGE AMPLITUDE MID/UPPER LEVEL PATTERN IS ESTABLISHED ACROSS THE WRN AND PART OF THE CNTRL ATLC. THE BASE OF A BROAD UPPER TROUGH EXTENDS ACROSS THE ERN GULF AND THE SW ATLC. AN ASSOCIATED COLD FRONT STRETCHES FROM 32N72W ACROSS THE WRN BAHAMAS AND CENTRAL CUBA. INSTABILITY ASSOCIATED WITH THE SFC BOUNDARY ALONG WITH UPPER DIFFLUENT AIR BETWEEN THE TROUGH MENTIONED AND NARROW SLIGHT RIDGING TO THE E IS GENERATING AN ABUNDANT AMOUNT OF MOISTURE BETWEEN 68W-80W EXCEPT NW OF A LINE FROM S FL TO 32N73W WHERE THE DRY AIR HAS WORKED ITS WAY IN. THIS MOISTURE DOES NOT APPEAR VERY DEEP IN NATURE...BASED ON IR IMAGERY...WITH ONLY SCATTERED SHOWERS EMBEDDED. A LARGE CUT OFF UPPER LOW IS CENTERED NEAR 27N56W. VERY DRY AIR LIES TO THE W AND S OF THE UPPER LOW EXTENDING INTO THE ERN CARIBBEAN. A LARGE AREA OF SCATTERED SHOWERS AND TSTMS EXISTS FROM 12N-32N BETWEEN 42W-55W ASSOCIATED WITH MOIST SLY UPPER LEVEL FLOW TO THE E OF THE LOW AND ENHANCED BY A TROPICAL WAVE ALONG 52W. A SMALL 1012 MB LOW IS LOCATED TO THE W OF THE LARGE AREA OF UNSETTLED WEATHER NEAR 29N58W PRODUCING ISOLATED SHOWERS WITHIN 300 NM OF ITS CENTER. THE FLOW THEN BECOMES FAIRLY ZONAL E OF 40W BETWEEN SLIGHT RIDGING IN THE TROPICS AND SLIGHT TROUGHING IN THE SUBTROPICS. SFC RIDGING IS WELL ESTABLISHED IN THE CNTRL AND ERN ATLC HELPING TO PRODUCE FAIR WEATHER E OF 40W. $$ CANGIALOSI