000 AXNT20 KNHC 210558 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 AM EDT SAT OCT 21 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 0530 UTC. ...TROPICAL WAVES... A TROPICAL WAVE IS ALONG 42W S OF 21N MOVING W 10 TO 15 KT. A 1010 MB LOW IS ALONG THE WAVE NEAR 14N. THIS LOW PRES AREA IS ONLY A ROTATION OF LOW CLOUDS WELL REMOVED FROM THE ASSOCIATED ISOLATED MODERATE CONVECTION A FEW HUNDRED NM TO ITS E. OBVIOUSLY THIS WAVE IS STILL FEELING EFFECTS OF STRONG W-SWLY SHEAR. ISOLATED MODERATE CONVECTION IS ALSO OCCURRING WITHIN 300 NM EITHER SIDE OF THE WAVE AXIS S OF 9N. THIS FEATURE WILL REMAIN IN AN UNFAVORABLE ENVIRONMENT OVER THE NEXT COUPLE OF DAYS. A WEAK TROPICAL WAVE IS ALONG 55W S OF 16N MOVING W 10 TO 15 KT. THIS WAVE DOES NOT EXHIBIT ANY SIGNATURE ON SATELLITE IMAGERY OR IN AVAILABLE SFC DATA...THEREFORE THE PSN IS BASED ON CONTINUITY. THIS FEATURE WILL LIKELY BECOME ABSORBED INTO THE BROAD TROUGH IN THE CARIBBEAN. ...THE ITCZ... ITCZ AXIS IS CENTERED ALONG 9N14W 6N32W 8N40W 9N54W 9N62W. THE ERN PORTION OF THE AXIS HAS BECOME A LITTLE MORE ACTIVE... SCATTERED MODERATE CONVECTION IS E OF 18W FROM 6N-12N. SCATTERED MODERATE IS WITHIN 180 NM S OF THE AXIS BETWEEN 17W-26W. ISOLATED MODERATE IS FROM 6N-12N BETWEEN 30W-35W. NUMEROUS MODERATE IS ALONG THE N COAST OF S AMERICA DRIFTING NWD FROM 11N-13N BETWEEN 63W-68W. ...DISCUSSION... THE GULF OF MEXICO... A WEAK SHORTWAVE TROUGH ACROSS THE NRN PORTION OF THE AREA HAS FLATTENED WITH UPPER LEVEL FLOW BECOMING MORE ZONAL ACROSS THE SRN U.S. AND NRN GULF. THIS HAS MADE THE ASSOCIATED FRONTAL BOUNDARY NEARLY STATIONARY ACROSS THE GULF. AS OF 03 UTC...THE FRONT WAS STILL ANALYZED AS A COLD FRONT FROM NEAR ST. AUGUSTINE TO 27N86W THEN STATIONARY TO A 1008 MB LOW NEAR 25N96W. THE FRONT THEN CONTINUES SWD TO 19N96W AND THEN NWD ALONG THE E SLOPES OF THE SIERRA MADRE MOUNTAINS IN MEXICO. THIS SFC BOUNDARY IS SLOWLY WEAKENING IN THE CENTRAL AND WRN GULF WITH WINDS VEERING FROM N-NE TO ENE N OF THE BOUNDARY OVER THE PAST SEVERAL HOURS. ONLY ISOLATED SHOWERS ARE FOUND WITHIN 150 NM N OF THE BOUNDARY AND NEAR THE LOW. TRANQUIL WEATHER CONTINUES ACROSS THE SRN PORTION OF THE GULF...THANKS TO DRY STABLE AIR ALOFT IN PLACE GENERATED BY A HIGHLY NE-SW ELONGATED MID/UPPER RIDGE. THE SFC FRONT IS EXPECTED TO LIFT NWD AS A WARM FRONT LATER TODAY BEFORE THE NEXT COLD FRONT...CURRENTLY DRAPED ACROSS THE CNTRL U.S....PUSHES OFF THE GULF COAST EARLY SUN. GFS ANTICIPATES THIS SECOND FRONT TO DIG MUCH FURTHER S POSSIBLY CLEARING THE ENTIRE AREA BY LATE MON. THE CARIBBEAN SEA... SOME UNSETTLED WEATHER IS CONTINUING IN THE ERN CARIBBEAN DUE TO A SLOW MOVING PERSISTENT DEEP LAYER TROUGH. A 1007 MB LOW IS ANALYZED OVER HISPANIOLA NEAR 19N70W WITH A SFC TROUGH EXTENDING SOUTHWESTWARD ALONG 16N74W 14N79W. DESPITE THE RATHER LOW SFC PRESSURES...THE LOW MENTIONED IS VERY BROAD AND POORLY STRUCTURED WITH ONLY ISOLATED SHOWERS IN ITS VICINITY. MOST OF THE MORE IMPRESSIVE RAINFALL IS OCCURRING FARTHER E ASSOCIATED WITH THE MOIST SWLY FLOW ON THE E SIDE OF THE MID/UPPER TROUGH DRAWING DEEP TROPICAL MOISTURE NWD. SCATTERED SHOWERS AND TSTMS ARE ACROSS THE WINDWARD...LEEWARD AND VIRGIN ISLANDS. SCATTERED TO NUMEROUS MODERATE CONVECTION IS MOVING NWD OFF THE NRN S AMERICA COAST FROM 11N-13N BETWEEN 63W-68W. GFS SHOWS THIS MOISTURE SLOWLY THINNING OUT AND DRIFTING W OVER THE NEXT FEW DAYS AS THE UPPER TROUGH MOVES W AND A WEAK UPPER RIDGE BUILDS OVER THE AREA. THE WRN CARIBBEAN REMAINS QUIET WITH VERY DRY AIR ALOFT BEING ADVECTED IN THE REGION FROM AN ELONGATED UPPER RIDGE TO THE N. SFC WINDS ARE LIGHT AND VARIABLE ACROSS THE CARIBBEAN DUE TO THE PRESENCE OF THE SFC TROUGH. EASTERLY TRADES WILL LIKELY RESUME LATE SAT/EARLY SUN. THE ATLANTIC OCEAN... A FAIRLY COMPLEX MID/UPPER LEVEL PATTERN EXISTS ACROSS THE ATLC. IN THE WRN ATLC...AN UPPER HIGH IN THE GULF OF MEXICO HAS RIDGING THAT EXTENDS NE ACROSS THE NRN BAHAMAS. ANOTHER UPPER HIGH IS CENTERED E OF BERMUDA NEAR 31N58W. VERY DRY STABLE AIR IS NOTED N OF 25N GENERATED BY THESE ANTICYCLONES. DEEP LAYER TROUGHING EXISTS BETWEEN THESE UPPER RIDGES WITH THE SFC BOUNDARY EXTENDING FROM A 1007 MB LOW OVER HISPANIOLA TO 24N67W. A LARGE AREA OF MOISTURE WITH EMBEDDED AREAS OF DEEP CONVECTION EXISTS S OF THE LARGE ANTICYCLONE NEAR BERMUDA AND E OF THE DEEP LAYER TROUGH IN THE CNTRL CARIBBEAN...NAMELY S OF 25N BETWEEN 50W AND 70W. THE DEEPEST BLOB OF CONVECTION IS NE OF PUERTO RICO FROM 19N TO 23N BETWEEN 61W AND 65W. DEBRIS UPPER LEVEL MOISTURE IS THEN ADVECTED EASTWARD BY A WLY JET N OF AN UPPER HIGH IN THE TROPICAL N ATLC...AS WELL AS ANOTHER FARTHER E NEAR 16N46W...AND S OF AN UPPER LOW NEAR 26N42W. THIS JET HAS CORE WINDS NEAR 80 KT BASED ON UW-CIMSS SATELLITE DERIVED WINDS. THE TROPICAL ERN ATLC IS DOMINATED BY UPPER RIDGING WITH AN ANTICYCLONE CENTERED OVER THE CAPE VERDE ISLANDS. THE E ATLC SFC PATTERN IS DOMINATED BY WEAK E-W RIDGING IN THE SUBTROPICS FROM A 1018 MB NEAR 31N57W TO A 1020 MB HIGH NEAR 27N32W TO A 1017 MB HIGH OVER MOROCCO. THIS RIDGE IS BLEMISHED A SFC TROUGH EXTENDING FROM A 1010 MB ALONG 32N48W 26N54W AND POSSIBLY ANOTHER TROUGH ASSOCIATED WITH THE UPPER LEVEL LOW NEAR 26N42W. $$ CANGIALOSI