000
AXPZ20 KNHC 182153
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2130 UTC.

...SPECIAL FEATURE...

TROPICAL STORM SERGIO IS CENTERED NEAR 15.6N 104.7W...OR 215 NM 
S OF MANZANILLO MEXICO...AT 18/2100 UTC MOVING NW 6 KT. MAXIMUM 
SUSTAINED WIND SPEED IS 45 KT WITH GUSTS TO 55 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 1000 MB. THE CENTER OF SERGIO IS 
PARTIALLY EXPOSED ON THE SW SIDE OF THE DEEP CONVECTION WITH THE 
SYSTEM STILL UNDER W/SWLY SHEAR NEXT TO AN UPPER LEVEL SHORTWAVE 
TROUGH. MEXICAN RADAR IMAGERY FROM ACAPULCO AND CUYUTLAN BOTH 
INDICATE BANDS OF SHOWERS/TSTMS MOVING INLAND OFF THE OCEAN AND 
THE HEAVIEST RAIN IS LIKELY TO OCCUR IN THE MOUNTAINS WITH 
ENHANCED LIFTING. SCATTERED MODERATE/STRONG CONVECTION FROM 
14N-18N BETWEEN 100W-106W. SEE LATEST NHC FORECAST/ADVISORY 
UNDER AWIPS/WMO HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N78W 9N90W 13N100W 14N110W 9N120W 
8N140W. ISOLATED MODERATE/STRONG N OF 4N E OF 92W AND WITHIN 120 
NM OF LINE 12N105W 8N117W 9N132W...AND WITHIN 120 NM OF 12N139W.

...DISCUSSION...

MID/UPPER LEVEL RIDGE EXTENDING FROM THE SUBTROPICS TO ALONG THE 
OREGON/WASHINGTON COAST HAS BEGUN TO FLATTEN OUT OVER THE PAST 
DAY OR SO BUT THE JET STREAM CONTINUES TO PENETRATE INLAND 
ACROSS THE NW UNITED STATES. THIS LEAVES THE EPAC DISCUSSION 
AREA UNDER WEAKER FLOW WITH AN UPPER TROUGH EXTENDING FROM 
30N122W TO 12N140W...AND WIDESPREAD SUBSIDENCE N OF 10N W OF 
110W AND EXTENDING ACROSS N MEXICO. SFC HIGH IS LOCATED JUST N 
OF THE AREA NEAR 32N128W WITH THE SUBTROPICAL WATERS COVERED BY 
PATCHES OF STRATOCUMULUS. ITCZ REMAINS MAINLY FLAT W OF 120W 
WITH ONLY SCATTERED SHOWERS.

E OF 120W...A 1008 MB LOW HAS PARTIALLY BROKEN AWAY FROM THE 
ITCZ NEAR 11N115W BUT HAS RELATIVELY LITTLE DEEP CONVECTION AS 
COMPARED TO YESTERDAY. THE BIGGER FEATURE IS TS SERGIO JUST SW 
OF MANZANILLO MEXICO WHICH HAS BEEN ABLE TO WITHSTAND MODERATE 
W/SWLY SHEAR JUST ENOUGH TO CONTINUE TO PRODUCE DEEP CONVECTION. 
THE SUBTROPICAL JET APPEARS AS THOUGH IT WILL NOT MOVE MUCH OVER 
THE NEXT FEW DAYS...WHICH WOULD KEEP A STATIC ENVIRONMENT OVER 
SERGIO AND HIGHER THAN NORMAL UNCERTAINTY IN THE STORM'S 
ULTIMATE FATE. FARTHER E...1008 MB LOW PRES HAS DRIFTED FARTHER 
W OF THE COSTA RICAN COAST NEAR 8N89W BUT STILL HAS LITTLE DEEP 
CONVECTION.

WINDS OVER THE GULF OF TEHUANTEPEC ARE CURRENTLY IN THE 20-25 KT 
RANGE BUT ARE EXPECTED TO INCREASE TO GALE FORCE WITHIN 24-30 
HRS (SUN EVENING). CONDITIONS COULD EVEN WORSEN BY MON EVENING 
WITH THE POTENTIAL OF STORM FORCE WINDS DEVELOPING...AND THE 
GALE FORCE WINDS EXPANDING OVER A WIDER SWATH OF REAL ESTATE.

$$
BERG