000 AXNT20 KNHC 262338 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 PM EDT THU OCT 26 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 ADDED TO THE 18 Z ANALYSIS ALONG 35W/36W S OF 13N MOVING W 10 TO 15 KT. SOME LOW TO MID LEVEL CLOUD TURNING IS APPARENT ON THE LAST FEW VIS IMAGES THIS EVENING EMBEDDED IN A LARGE MASS OF MOISTURE...ASSOCIATED WITH THE ITCZ AND ENHANCED BY AN UPPER LOW TO ITS N. DUE TO THE ABUNDANT HIGH LEVEL MOISTURE IN THE REGION IT IS DIFFICULT TO FIND THE LOCATION OF THE LOW-LEVEL WAVE AXIS. HOWEVER...THERE IS A FAIR AMOUNT OF CONFIDENCE IN INTRODUCING THIS WAVE BASED ON A TRACKABLE FEATURE IN THE MET-9 HOVMOLLER DIAGRAMS AND LOW-LEVEL VORTICITY ANALYSIS. A TROPICAL WAVE IS ALONG 52W/53W S OF 20N MOVING W 10 TO 15 KT. A 1010 MB LOW IS ALONG THE WAVE NEAR 13N. THIS LOW PRES SYSTEM HAS BECOME BETTER DEFINED WITH THE LOW-LEVEL CENTER NOW FAIRLY EASY TO LOCATE ON SATELLITE IMAGES. DESPITE THE FAIR STRUCTURE OF THIS SYSTEM...SHOWERS AND TSTMS REMAIN MINIMAL AND DISORGANIZED FROM 11N-16N BETWEEN 50W-56W...THEREFORE FURTHER DEVELOPMENT IS NOT ANTICIPATED AT THIS TIME. A WEAK TROPICAL WAVE IS ALONG 68W S OF 19N MOVING W 10 TO 15 KT. CYCLONIC WIND SHIFTS ARE EVIDENT IN THE LOW-LEVELS BASED UPON SFC OBSERVATIONS...QSCAT AS WELL AS SAT IMAGES. THE WAVE IS EMBEDDED IN A DRY ENVIRONMENT JUST SE OF THE STRONG ATLC FRONTAL BOUNDARY...PRODUCING ONLY ISOLATED SHOWERS. ...THE ITCZ... ITCZ AXIS IS ALONG 10N14W 7N26W 6N37W 12N50W. A LARGE AREA OF ISOLATED MODERATE CONVECTION...PARTLY ASSOCIATED WITH THE TROPICAL WAVE ALONG 35W/36W...IS FROM 1N-12N BETWEEN 30W-44W. SCATTERED MODERATE IS WITHIN 90 NM N OF THE AXIS BETWEEN 20W-30W. ...DISCUSSION... THE GULF OF MEXICO... MOST OF THE AREA IS SLIGHTLY WARMER AND MORE HUMID TODAY THAN THE PAST FEW DAYS AS RETURN FLOW HAS BECOME MORE UNIFORMLY ESTABLISHED ACROSS THE GULF. S AND SE WINDS ARE IN THE 15-20 KT RANGE ACROSS THE REGION. NEARLY THE ENTIRE GULF OF MEXICO IS RAIN-FREE...DUE TO SFC HIGH PRES AND MODERATE AIR ALOFT IN PLACE...EXCEPT FOR SCATTERED SHOWERS AND TSTMS MOVING NWD IN THE YUCATAN CHANNEL AND NUMEROUS SHOWERS AND TSTMS ACROSS THE U.S. GULF COAST AND COASTAL WATERS. THE LATTER IS ASSOCIATED WITH THE NEXT FRONTAL SYSTEM THAT WILL ENTER THE NW PORTION OF THE REGION LATE TONIGHT OR TOMORROW MORNING. THIS FRONT WILL BRING AN INCREASE IN MOISTURE AHEAD OF IT AND COOLER/DRIER AIR BEHIND IT. NLY WINDS WILL INCREASE WITH GUSTS TO GALE FORCE BUILDING HIGH SEAS AS STRONG SFC RIDGING BUILDS IN BEHIND THE FRONT. THE CARIBBEAN SEA... THE TAIL END OF A STRONG ATLC FRONTAL BOUNDARY IS LOSING ITS IDENTITY IN THE CARIBBEAN AND IS ANALYZED AS A TROUGH AT 21 Z FROM HISPANIOLA TO THE NE PART OF THE YUCATAN PENINSULA. A BROKEN LINE OF SCATTERED SHOWERS AND TSTMS ARE WITHIN 120 NM S OF THE BOUNDARY E OF 78W AND WITHIN 120 NM EITHER SIDE W OF 78W. THE WRN PORTION OF THIS BOUNDARY IS BEING DRIVEN NWD BY SFC RETURN FLOW. SCATTERED SHOWERS AND TSTMS ARE ALSO OCCURRING ACROSS A GOOD PORTION OF CENTRAL AMERICA AND THE SW CARIBBEAN S OF 16N W OF 80W. THIS ACTIVITY IS ASSOCIATED WITH MOIST SLY UPPER LEVEL FLOW BETWEEN A WEAKENING SMALL UPPER TROUGH IN THE NW CARIB AND AN UPPER HIGH CENTERED NEAR 14N78W. THE ERN CARIBBEAN IS MAINLY DRY WITH MODERATE DRY AIR ALOFT...BUT THE AIR IS MOISTENED UP SLIGHTLY WITH NLY UPPER LEVEL FLOW SPREADING SOME MOISTURE INTO THE REGION FROM THE DEEP LAYER TROUGH TO THE N. SCATTERED SHOWERS EXISTS IN THE LESSER ANTILLES AND ISOLATED SHOWERS ARE IN THE VICINITY OF THE WEAK TROPICAL WAVE ALONG 68W. MOISTURE WILL LIKELY BE ON THE INCREASE IN THE ERN CARIB THIS WEEKEND AS A TROPICAL WAVE AND WEAK AREA OF LOW PRES...CURRENTLY 450 NM E OF THE LESSER ANTILLES...MOVES INTO THE AREA. THE ATLANTIC OCEAN... A HIGHLY AMPLIFIED PATTERN IS ESTABLISHED ACROSS THE ATLC. HIGH PRES RIDGING EXISTS ACROSS THE ERN U.S. AND A PORTION OF THE WRN ATLC W OF 73W. A LARGE STRONG TROUGH LIES TO THE E OF THE RIDGE. THE HIGHEST AMPLITUDE OF THE TROUGH IS ASSOCIATED WITH A POLAR LOW BUT STILL 80-100 KT SW-WLY UPPER LEVEL JET...BASED ON CIMSS DERIVED WINDS...EXTENDS ACROSS THE N PORTION OF THE DISCUSSION AREA BETWEEN 45W-73W. AN ASSOCIATED COLD FRONT REMAINS WELL DEFINED ALONG 32N47W 24N60W TO THE DOMINICAN REPUBLIC. SCATTERED SHOWERS AND TSTMS ARE WITHIN 180 NM E OF THE FRONT. BEHIND THE FRONT...A DRIER AND COOLER AIRMASS EXISTS. SEVERAL SHIPS ARE REPORTING SEAS 8 TO 13 FT IN NLY SWELL. REFER TO MIAHSFAT2 AND OFFNT3 FOR DETAILS. A LARGE STRONG MID/UPPER LEVEL RIDGE IS LOCATED E OF THE TROUGH CENTERED IN THE SUBTROPICS NEAR 29N31W. THIS RIDGE COVERS THE REMAINDER OF THE ATLC E OF 45W WITH DRY STABLE AIR ALOFT WIDESPREAD IN THE REGION. SFC HIGH PRES IS ALSO ANALYZED UNDERNEATH THE MID/UPPER RIDGE WITH A 1022 MB HIGH NEAR 32N29W AND A 1018 MB HIGH NEAR 24N40W. SWIFT NLY LOW LEVEL FLOW ON THE E SIDE OF THE SFC RIDGE IS PRESSING THE ITCZ FAIRLY FAR S IN THE E ATLC. AN UPPER LOW...WHICH CUT OFF FROM THE STRONG TROUGH THAT WAS IN THE E ATLC EARLIER THIS WEEK...IS TRACKING W CENTERED NEAR 16N35W. UPPER DIFFLUENCE ON THE SE SIDE OF THIS LOW IS GENERATING A LARGE AREA OF HIGH LEVEL MOISTURE IN THE ITCZ BETWEEN 30W-45W. $$ CANGIALOSI