000
AXPZ20 KNHC 180317
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT NOV 18 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 IS CENTERED NEAR 14.5N 103.1W...OR 210 NM 
SSW OF ZIHUATANEJO MEXICO...AT 18/0300 UTC MOVING NW 6 KT. 
MAXIMUM SUSTAINED WIND SPEED IS 40 KT WITH GUSTS TO 50 KT. 
ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB. EVEN THOUGH THE 
LOW-LEVEL CENTER OF SERGIO HAD BECOME EXPOSED DUE TO W/SW SHEAR 
EARLIER IN THE DAY...DEEP CONVECTION HAS ONCE AGAIN DEVELOPED 
NEAR THE CENTER AND IS KEEPING THE CYCLONE AT THE SAME 
INTENSITY. NUMEROUS MODERATE/STRONG CONVECTION IS FROM 14N-16N 
BETWEEN 100W-104W. SCATTERED MODERATE IS ELSEWHERE FROM 12N-15N 
BETWEEN 99W-101W. SEE LATEST NHC FORECAST/ADVISORY UNDER 
AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS. 

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N84W 8N86W 14N100W 9N120W 8N140W. 
SCATTERED MODERATE WITHIN 180 NM OF AXIS BETWEEN 106W-118W.

...DISCUSSION...

LARGE-SCALE MID/UPPER RIDGE PATTERN CONTINUES OVER THE 
SUBTROPICAL E PACIFIC WATERS WITH TWO EMBEDDED CUT-OFF 
LOWS/TROUGHS. ONE TROUGH EXTENDS FROM 30N128W TO 18N140W AND IS 
SURROUNDED BY AN AREA OF MODERATE/STRONG SUBSIDENCE...AND THE 
OTHER (AN UPPER LOW) IS CENTERED NEAR 20N116W ALSO SURROUNDED BY 
ABUNDANT DRY AIR. A 1020 MB SURFACE HIGH IS PLANTED BENEATH 
THESE FEATURES NEAR 29N135W WITH GENERALLY BENIGN WEATHER N OF 
20N.

THE ITCZ IS QUITE LINEAR AND NOT VERY CONVECTIVE W OF 120W WITH 
THE ABSENCE OF ANY DEEP UPPER TROUGHS IN THE VICINITY. E OF 120W 
HOWEVER...THE UPPER LOW NEAR 20N116W IS PRODUCING A HIGHLY 
DIFFLUENT ENVIRONMENT SW OF THE MEXICAN COAST. A 1008 MB LOW IS 
EMBEDDED ALONG THE ITCZ NEAR 11N115W AND HAS ACQUIRED A GOOD 
AMOUNT OF DEEP CONVECTION...WITH SCATTERED MODERATE/STRONG 
WITHIN 150 NM S SEMICIRCLE. UPPER FLOW EMANATING AWAY FROM THIS 
AREA OF CONVECTION IS SCREAMING EWD RIGHT OVER T.S. SERGIO AND 
CONTRIBUTING TO THE CYCLONE'S DEMISE. ANOTHER AREA OF LOW 
PRESSURE...1009 MB...IS STILL LOCATED SW OF THE NICOYA PENINSULA 
OF COSTA RICA NEAR 8N88W BUT HAS MINIMAL CONVECTION.

THE GALE EVENT OVER THE GULF OF TEHUANTEPEC HAS ENDED FOR THE 
TIME BEING...BUT IT APPEARS LIKELY THAT ANOTHER GALE WILL BEGIN 
IN ABOUT 48 HRS (OR SUN EVENING) AS ANOTHER PUSH OF COLD AIR 
SURGES THROUGH THE GULF OF MEXICO. THIS EVENT LOOKS AS THOUGH IT 
COULD BE STRONGER THAN THE PREVIOUS EVENT...POSSIBLY CLOSE TO 
STORM FORCE BY MON EVENING.

$$
BERG