000 AXNT20 KNHC 221050 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SUN OCT 22 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 1045 UTC. ...TROPICAL WAVES... A HIGH AMPLITUDE TROPICAL WAVE IS ALONG 46W S OF 24N MOVING W NEAR 10 KT. THIS WAVE HAS DEVELOPED A CLASSIC INVERTED V SIGNATURE. THE WEAK SFC LOW PREVIOUSLY ANALYZED ALONG THIS WAVE HAS BEEN DROPPED DUE TO THE LACK OF A CLOSED CIRCULATION BASED ON SATELLITE IMAGES AND QUIKSCAT DATA. ASSOCIATED CONVECTION IS MINIMAL AND MAINLY EMBEDDED IN THE ITCZ EXCEPT FOR A PATCH OF SCATTERED MODERATE CONVECTION FROM 18N-21N BETWEEN 42W-44W. GLOBAL MODELS...THAT HAVE THIS FEATURE INITIALIZED...CONTINUE TO TRACK IT WNW AS AN OPEN WAVE. THE WEAK TROPICAL WAVE THAT WAS PREVIOUSLY ANALYZED NEAR THE LESSER ANTILLES HAS BEEN REMOVED FROM THE SFC ANALYSIS DUE TO THE LACK OF EVIDENCE OVER THE PAST SEVERAL DAYS. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 13N17W 7N30W 6N41W 8N48W 7N59W. SCATTERED MODERATE CONVECTION IS WITHIN 300 NM S OF THE AXIS E OF 20W. SIMILAR CONVECTION IS WITHIN 240 NM EITHER SIDE BETWEEN 21W-45W. SOME OF THIS CONVECTION IS BEING ENHANCED BY THE LARGE TROPICAL WAVE ALONG 46W. ...DISCUSSION... THE GULF OF MEXICO... QUIET WEATHER EXISTS ACROSS MUCH OF THE GULF OF MEXICO THIS MORNING THANKS TO DRY STABLE AIR ALOFT GENERATED BY AN ELONGATED UPPER RIDGE STRETCHED ACROSS THE AREA ORIGINATING FROM A HIGH CENTER IN THE SW GULF. AT THE SFC...A WARM FRONT EXTENDS ACROSS N FLORIDA FROM NEAR DAYTONA BEACH TO THE MS/FL BORDER NEAR 31N 86.5W. SFC FLOW IS GENERALLY LIGHT FROM THE SE TO S ACROSS MOST OF THE GULF PRODUCING TYPICAL EARLY FALL WARM AND HUMID CONDITIONS. HOWEVER A CHANGE IN AIRMASS IS IN STORE FOR THE AREA AS A STRONG COLD FRONT HAS PUSHED OFF THE SE TEXAS COASTLINE. AS OF 09 UTC...THE COLD FRONT WAS ANALYZED FROM CENTRAL LOUISIANA TO S TEXAS. TEMPS HAVE FALLEN INTO THE 40'S AND 50'S BEHIND THE BOUNDARY IN TEXAS AND NRN LOUISIANA WITH DEWPOINTS IN THE 30'S. S AND E OF THE FRONT THESE VALUES ARE IN THE 70'S. A TROUGH WAS ANALYZED AHEAD OF THE FRONT EARLIER THIS MORNING...BUT BECAUSE OF THE FAST MOTION OF THE COLD FRONT IT APPEARS THAT THESE FEATURES HAVE MERGED. A LINE OF SHOWERS AND TSTMS ARE WITHIN 90 NM AHEAD OF THE BOUNDARY. THIS FRONTAL SYSTEM WILL LIKELY CLEAR THE ENTIRE AREA LATE MON BRINGING MODIFIED COOLER AND MUCH DRIER AIR WITH IT. AN INCREASE IN NLY WINDS AND SEAS WILL FOLLOW THE BOUNDARY AS SFC HIGH PRES BUILDS IN BEHIND IT. THE CARIBBEAN SEA... THE WEATHER IN THE CARIBBEAN HAS BECOME MUCH LESS ACTIVE THIS MORNING COMPARED TO THE PAST COUPLE OF DAYS. ONLY ISOLATED SHOWERS AND TSTMS ARE EMBEDDED IN A THINNING UPPER LEVEL MOISTURE PLUME E OF 70W. THIS MOISTURE IS MAINLY ASSOCIATED WITH DEBRIS TROPICAL MOISTURE ROTATING AROUND AN ANTICYCLONE CENTERED OVER THE LEEWARD ISLANDS. MORE IMPRESSIVE CONVECTION IS ON THE N SIDE OF THE RIDGE ASSOCIATED WITH A SFC LOW LOCATED ABOUT 300 NM NNE OF PUERTO RICO. THE CENTRAL AND WRN CARIBBEAN REMAIN QUIET WITH ONLY WIDELY SCATTERED SHOWERS. HOWEVER THE ATMOSPHERE ALOFT IS NOT AS STABLE AS IT WAS OVER THE PAST FEW DAYS DUE TO AN UPPER LOW...WHICH IS MOISTENING THE AIR SLIGHTLY...TRACKING WWD NOW CENTERED ABOUT 150 NM SW OF JAMAICA. A WEAK SFC TROUGH IS ANALYZED FROM THE LOW NE OF PUERTO RICO TO HISPANIOLA CONTINUING SOUTHWESTWARD TO THE BORDER OF HONDURAS/NICARAGUA. SFC WINDS ARE LIGHT AND VARIABLE NEAR THE TROUGH BUT APPEAR TO BE FROM A MORE TYPICAL EAST DIR ELSEWHERE. THESE WINDS ARE EXPECTED TO BECOME MORE UNIFORM FROM THE E AND INCREASE SLIGHTLY OVER THE NEXT DAY OR TWO. THE ATLANTIC OCEAN... IN THE WRN ATLC...AN UPPER HIGH IN THE SW GULF OF MEXICO HAS RIDGING THAT EXTENDS NE ACROSS THE NRN BAHAMAS. ANOTHER UPPER LEVEL RIDGE IS CENTERED OVER THE ERN CARIBBEAN AND CENTRAL ATLC WITH TWO HIGH CENTERS ONE NEAR 28N50W...WHICH IS GETTING PUSHED QUICKLY ESE...AND THE OTHER DRIFTING W OVER THE LEEWARD ISLANDS. A SLIGHT WEAKNESS IN THE RIDGE EXISTS OVER THE SRN BAHAMAS DUE TO THE UPPER LOW IN THE WRN CARIBBEAN. THIS PATTERN HAS PRODUCED PLENTY OF VERY DRY STABLE AIR N OF 25N W OF 45W. A THINNING MOISTURE PLUME EXISTS S OF 26N BETWEEN 53W AND 70W. MOST OF THE MOISTURE IN THIS REGION IS NOT DEEP IN NATURE EXCEPT FOR ONE AREA OF CONVECTION THAT HAS BEEN PERSISTING FROM 22N TO 25N BETWEEN 61W AND 65W. THIS CONVECTION IS ASSOCIATED WITH A 1011 MB SFC LOW PRES SYSTEM NEAR 24N65W WITH A TROUGH EXTENDING FROM THIS LOW SOUTHWESTWARD TO HISPANIOLA AND NORTHEASTWARD TO 29N61W. THE SFC CIRCULATION IS CLEARLY EXPOSED...LOCATED ABOUT 30-50 NM W OF THE WRN EDGE OF THE DEEP CONVECTION. WLY UPPER LEVEL WINDS...ON THE N PERIPHERY OF THE ANTICYCLONE OVER THE LEEWARD ISLANDS...IS PROVIDING UNFAVORABLE CONDITIONS RESTRICTING THE CONVECTION TO WRAP AROUND THE SFC LOW. THE UPPER LEVEL ENVIRONMENT MAY BECOME SLIGHTLY LESS HOSTILE OVER THE NEXT DAY OR SO BEFORE BECOMING VERY UNFAVORABLE AS A LARGE TROUGH MOVES OFF THE U.S. COAST. THE TROPICAL ERN ATLC IS DOMINATED BY UPPER RIDGING WITH AN ANTICYCLONE CENTERED A COUPLE HUNDRED NM SSW OF THE CAPE VERDE ISLANDS. UPPER LEVEL EASTERLY FLOW ON THE S SIDE OF THE RIDGE IS ENHANCING CONVECTION IN THE ITCZ E OF 45W. AN ELONGATED TROUGH STRETCHES FROM THE CANARY ISLANDS WSW ALONG 26N25W TO A DEVELOPING CUT OFF NEAR 24N35W. THE SFC PATTERN IS DOMINATED BY E-W RIDGING...WHICH IS FAIRLY FAR S IN THE SUBTROPICS...FROM A 1019 MB HIGH NEAR 28N53W TO A 1018 MB HIGH NEAR 25N30W. THIS RIDGE IS BLEMISHED BY THE LARGE TROPICAL WAVE IN THE REGION AND A BENIGN SFC TROUGH ALONG 32N38W 28N41W. $$ CANGIALOSI