000 AXNT20 KNHC 252333 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT WED OCT 25 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 IS ALONG 47W S OF 19N MOVING W NEAR 15 KT OVER THE PAST 24 HOURS. THIS WAVE HAS BECOME BETTER ORGANIZED TODAY WITH A LARGE ENVELOPE OF CYCLONIC TURNING EVIDENT IN THE LOW AND MID LEVEL CLOUDS AND APPARENT IN SFC OBSERVATIONS. A 1011 MB LOW IS ALONG THE WAVE NEAR 12N...HOWEVER THE LOW LEVEL CIRCULATION IS NOT EASILY IDENTIFIABLE IN SATELLITE IMAGES. SCATTERED MODERATE CONVECTION IS WITHIN 180 NM EITHER SIDE OF THE AXIS S OF 16N. THE WAVE IS CURRENTLY BENEATH AN UPPER ANTICYCLONE WHICH LIKELY ALLOWED THIS FEATURE TO BECOME BETTER ORGANIZED TODAY...HOWEVER SIGNIFICANT DEVELOPMENT IS NOT EXPECTED. A SFC TROUGH IS ANALYZED ALONG 13N55W 20N57W. SFC OBSERVATIONS HELPED CONSIDERABLY IN DEFINING THIS AXIS. A 3 DAY SATELLITE ANIMATION AND 850 MB RELATIVE VORTICITY ANALYSIS FROM UW-CIMSS SUGGESTS THAT THIS FEATURE MAY BE A TROPICAL WAVE...HOWEVER BECAUSE MUCH OF ITS ENERGY IS NOW MOVING NW AND DUE TO THE FEATURE LOSING SOME IDENTITY IT REMAINS ANALYZED AS A TROF. CONVECTION HAS BEEN ON THE DECREASE OVER THE LAST SEVERAL HOURS AND CURRENTLY ISOLATED MODERATE WITHIN 240 NM EITHER SIDE OF THE TROUGH AXIS. A TROPICAL WAVE IS IN THE ERN CARIBBEAN ALONG 63W S OF 20N MOVING W NEAR 10 KT. SLIGHT LOW AND MID LEVEL CYCLONIC TURNING IS EVIDENT WITH A HINT OF A WEAK INVERTED V SIGNATURE. THE WAVE IS EMBEDDED IN A DRY STABLE ENVIRONMENT. ONLY ISOLATED SHOWERS ARE WITHIN 120 NM OF THE AXIS. A LOW AMPLITUDE TROPICAL WAVE IS ALONG 76W S OF 16N DRIFTING W AS IT REMAINS IN AN AREA OF WEAK STEERING. THIS WAVE WAS RELOCATED EARLIER TODAY DUE TO SOME ROTATION IN THE CLOUDS...WHICH BECAME MORE EVIDENT...ABOUT THE ANALYZED AXIS. SHOWER ACTIVITY IS MINIMAL AND LIKELY ASSOCIATED WITH THE ITCZ AND THE UPPER TROUGH TO ITS W. ...THE ITCZ... ITCZ AXIS IS ALONG 8N14W 5N30W 12N46W 11N53W 14N60W. BESIDES FOR THE CONVECTION OUTLINED IN THE TROPICAL WAVES SECTION...ISOLATED MODERATE IS WITHIN 300 NM N AND 240 NM S OF THE AXIS BETWEEN 29W-41W. ...DISCUSSION... THE GULF OF MEXICO... FAIR WEATHER CONTINUES ACROSS THE MAJORITY OF THE GULF SUPPORTED BY A SFC HIGH PRES RIDGE CENTERED ACROSS THE SE U.S. AND MODERATELY DRY AIR ALOFT. SFC WINDS ARE FLOWING ANTICYCLONICALLY AROUND THE RIDGE AND ARE GENERALLY FROM THE E IN THE ERN GULF TURNING SE-S IN THE WRN GULF. SEVERAL BUOYS IN THE WRN GULF ARE REPORTING WINDS NEAR 20 KT. THE ONLY AREA OF ANY ACTIVITY IS IN THE SW GULF WHERE SCATTERED SHOWERS AND ISOLATED TSTMS ARE FROM 19N-24N BETWEEN 93W-96W. THIS IS ASSOCIATED WITH RETURN FLOW MOISTURE AND A WEAK SFC TROUGH WHICH BROKE OFF FROM THE LARGE FRONT IN THE ATLC AND CARIB. THE SFC RIDGE IS EXPECTED TO SLIDE EASTWARD AS A COLD FRONT PUSHES OFF THE TEXAS COAST EARLY FRI. GFS SUGGESTS THAT THIS FRONT WILL BE QUITE STRONG...BUT NOT AS STRONG AS THE PREVIOUS ONE...POSSIBLY CLEARING THE ENTIRE AREA LATE THIS WEEKEND...BRINGING AN INCREASE IN WINDS AND SEAS BEHIND IT. THE CARIBBEAN SEA... THE TAIL END OF THE ATLC FRONTAL BOUNDARY EXTENDS FROM ERN CUBA TO NRN BELIZE. SCATTERED SHOWERS AND TSTMS ARE WITHIN 90 NM EITHER SIDE OF THE STATIONARY FRONT. SOME TROPICAL MOISTURE IS BEING ADVECTED NWD BETWEEN 77W AND 82W BY S-SWLY FLOW BETWEEN THE UPPER TROUGH MENTIONED AND A UPPER HIGH CENTERED NEAR 13N77W. SCATTERED MODERATE CONVECTION HAS BLOSSOMED THIS EVENING ACROSS HISPANIOLA INFLUENCED BY THE MOIST SWLY FLOW AND SOME LOW-LEVEL CONVERGENCE AHEAD OF THE COLD FRONT...AS WELL AS LOCAL TOPOGRAPHIC LIFT. OTHERWISE...THE CENTRAL AND ERN CARIB IS QUIET WITH PLENTY OF DRY STABLE AIR ALOFT GENERATED BY AN UPPER HIGH OVER THE LEEWARD ISLANDS. A TROPICAL WAVE IS CURRENTLY EMBEDDED IN THIS STABLE ENVIRONMENT SQUEEZING OUT A SMALL AREA OF SCATTERED SHOWERS ACROSS THE NRN LESSER ANTILLES. THE ATLANTIC OCEAN... A STRONG COLD FRONT HAS PUSHED ACROSS MUCH OF THE WRN ATLC AND IS NOW ANALYZED ALONG 32N53W 23N65W ACROSS THE SE BAHAMAS. COLD AIR STRATOCUMULUS CLOUDS...STRONG WLY UPPER WINDS AND DRY AIR ALOFT ARE WIDESPREAD ACROSS THE OCEAN BEHIND THE BOUNDARY. SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM E OF THE FRONT. AN AMPLIFIED RIDGING PATTERN EXISTS IN THE CENTRAL ATLC FROM AN ANTICYCLONE IN THE TROPICAL ATLC NEAR 14N48W TO THE MAIN SUBTROPICAL ANTICYCLONE NEAR 27N38W. THIS HIGH PRES IS ALSO ANALYZED AT THE SFC WITH A 1020 MB HIGH NEAR 29N35W AND A 1019 MB HIGH NEAR 23N40W. NLY FLOW ON THE E SIDE OF THIS SFC RIDGE IS PRESSING THE ITCZ FAR S IN THE E ATLC. A WEAK UPPER LOW...E OF THE WRN ATLC TROUGH AND W OF THE SUBTROPICAL RIDGE IS ERODING THE WRN EDGE OF THE AMPLIFIED RIDGE. SCATTERED SHOWERS AND TSTMS ARE MAINLY S OF 18N BETWEEN 42W AND 60W ASSOCIATED WITH THE TROPICAL WAVES. VERY DRY AIR IS ASSOCIATED WITH THE MAIN ANTICYCLONE BETWEEN 30W-45W. THE LARGE STRONG TROUGH THAT HAS BEEN IN THE E ATLC OVER THE PAST COUPLE OF DAYS IS PULLING E OF THE AREA EXCEPT FOR AN UPPER LOW WHICH CUT OFF FROM THE TROUGH AND IS MOVING W CENTERED NEAR 15N30W. MOISTURE ASSOCIATED WITH THIS UPPER LOW IS MINIMAL. IN FACT...NEARLY ALL OF THE SHOWER ACTIVITY IN THE E/CENTRAL ATLC IS CONFINED TO THE ITCZ AND TROPICAL WAVES. $$ CANGIALOSI