000
AXPZ20 KNHC 190949
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN NOV 19 2006

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0245 UTC.

...SPECIAL FEATURE...
TROPICAL STORM SERGIO AT 15.7N 105.1W...210 NM S OF MANZANILLO 
MEXICO...AT 0900 UTC MOVING WNW 5 KT.  MAXIMUM SUSTAINED WIND 
SPEED HAS DECREASED TO 40 GUSTS TO 50 KT.  ESTIMATED MINIMUM 
CENTRAL PRESSURE 1002 MB.  STRONG SWLY SHEAR CONTINUES TO POUND 
THE SYSTEM BLOWING DEEP CONVECTION NE OF LOW LEVEL CENTER AND 
EXPOSING IT...ALTHOUGH NUMEROUS TSTMS STILL CONTINUE.  SERGIO IS 
DRIFTING W APPROACHING A DRY AIR MASS WHICH SHOULD SHOULD SPELL 
THE LAST OF THE STORM.  UNTIL THEN...NUMEROUS MODERATE/STRONG 
CONVECTION FROM 15N-17N BETWEEN 102W-105W.  SEE LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC 
FOR MORE DETAILS.

...ITCZ...
ITCZ AXIS ALONG  8N82W  8N92W  14N104W  7N126W  7N140W.  
SCATTERED MODERATE CONVECTION WITHIN 60 NM OF AXIS FROM 122W TO 
130W.  ISOLATED MODERATE WITHIN 90 NM OF AXIS E OF 86W.

...DISCUSSION...
WEAK MID/UPPER LEVEL CYCLONIC VORTEX AT 23N121W HAS UPPER LEVEL 
TROUGH DIG SW TO 15N140W BREAKING THE STRONGHOLD THE BROAD UPPER 
LEVEL RIDGE HAD W OF 130W.  TROUGH IS IMPACTING NEGATIVELY IN 
ITCZ DEVELOPMENT AS MODERATE 40 KT WIND SHEARS OFF DEEP 
CONVECTION.  ONLY EXCEPTION IS LOW PRES 1008 NEAR 11N115W WHERE 
WEAK DEFORMATION ZONE DIVERGES WIND ALOFT ENHANCING DEEP 
CONVECTION.  SECOND NEGATIVE INFLUENCE OF TROUGH IS BRINGING DRY 
AIR S OF 20N.  SERGIO IS ABOUT TO ENTRAIN SOME OF THIS DRY AIR 
AND WITH SW SHEAR ALOFT HAS THE CARDS STACKED AGAINST IT. 

OTHERWISE BROAD MID/UPPER LEVEL RIDGE SITS OVER REMAINDER OF 
BASIN...CENTRAL AMERICA AND CARIBBEAN BASIN.  RIDGE ADVECTING 
ABUNDANT TROPICAL MOISTURE INTO WRN CARIBBEAN WHERE DEEP LAYER 
TROUGH ALONG ERN SEABOARD IS LIKELY TO PROMPT SOME CONVECTION.  

AT THE SURFACE...HEALTHY BURST OF COLD AIR MASS FORCED S BY LOW 
PRES OVER SW N ATLC BRINGS STRONG WINDS ALL THE WAY INTO GULF OF 
MEXICO AND WRN CARIBBEAN.  GULF OF TEHUANTEPEC EXPECTED TO 
SUDDENLY INCREASE TO GALE FORCE WITHIN 12 HRS WHILE GULFS OF 
PAPAGAYO AND FONSECA WILL BECOME STRONG SLIGHTLY LATER AS COLD 
AIR MASS REACHES FAR INTO THE TROPICS.

ELSEWHERE...HIGH PRES RIDGE CENTERED AT 32N128W WILL MAINTAIN 
MODERATELY STRONG NE TRADES W OF 120W BUT WEAKEN NEXT 24 HRS AS 
RIDGE IS FORCED EWD BY INCOMING COLD FRONT APPROACHING NW CORNER 
OF E PAC. 

$$
WALLY BARNES