000
AXPZ20 KNHC 170308
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI NOV 17 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...

HURRICANE SERGIO IS CENTERED NEAR 13.8N 102.7W...OR 245 NM SW OF 
ACAPULCO MEXICO...AT 17/0300 UTC MOVING N AT 4 KT. MAXIMUM 
SUSTAINED WIND SPEED IS 70 KT WITH GUSTS TO 85 KT. ESTIMATED 
MINIMUM CENTRAL PRESSURE IS 982 MB. SERGIO BEGAN PRODUCING A 
LARGE BURST OF DEEP CONVECTION NEAR ITS CENTER AROUND 2300 UTC 
BUT OVER THE PAST HOUR OR SO THE WESTERLY SHEAR IS WINNING OUT 
AS THE CLOUD CANOPY DRIFTS EWD...WITH THE WRN EDGE ACQUIRING A 
SHARP EDGE (INDICATIVE OF SHEAR). A SHARP MID/UPPER LEVEL 
SHORTWAVE TROUGH IS JUST NW OF SERGIO ALONG 105W AND IS 
PRODUCING THE SHEAR...AS WELL AS PROVIDING DIFFLUENCE TO HELP 
THE CONVECTION OCCASIONALLY REGENERATE. NUMEROUS MODERATE/STRONG 
CONVECTION IS FROM 12N-16N BETWEEN 99W-103W. RADAR IMAGERY FROM 
ACAPULCO HAS SHOWN WAVES OF LIGHT/MODERATE RAIN MOVING INLAND 
ALONG THE SW MEXICAN COAST AND TOTAL ACCUMULATIONS OF 3-5" ARE 
EXPECTED IN THE AREA WITH ISOLATED AMOUNTS UP TO 8" IN THE 
MOUNTAINS. SEE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO 
HEADERS MIATCMEP1/WTPZ21 KNHC FOR MORE DETAILS.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N83W 7N90W 12N99W 7N118W 6N140W. 
SCATTERED MODERATE CONVECTION FROM 8N-13N BETWEEN 102W-119W.

...DISCUSSION...

UPPER LEVEL FLOW OVER THE E PACIFIC WATERS IS DOMINATED BY A 
LARGE-SCALE RIDGE ALONG 128W WHICH IS PROPELLING THE MOST ACTIVE 
WEATHER ACROSS THE NW UNITED STATES. RIDGE EXTENDS INTO THE 
DISCUSSION AREA WITH A CUT-OFF LOW EMBEDDED ROUGHLY NEAR 
18N140W. THIS LOW IS PULLING SOME MOISTURE NWD BETWEEN 125W-135W 
TO 24N...BUT OVERALL THE REGION W OF 115W IS DOMINATED BY DRY 
AIR AND SUBSIDENCE. THIS HAS IN EFFECT KEPT THE ITCZ QUIET AT 
THE MOMENT.

FARTHER E...A 1008 MB LOW IS CENTERED NEAR 11N117W BUT IS UNDER 
STRONG WLY SHEAR WITH THE DEEPEST CONVECTION SHIFTED E OF THE 
CENTER. THE DEEPEST MOISTURE CONTINUES EWD TOWARDS HURRICANE 
SERGIO...WHICH IS LIKELY ENHANCING RAINFALL ALONG THE MEXICAN 
COAST BETWEEN THE GULF OF TEHUANTEPEC AND MANZANILLO. RAINFALL 
GUIDANCE SUGGESTS THAT BETWEEN 3-6"/DAY IS FALLING ALONG THE SW 
MEXICAN COAST...ESPECIALLY ON THE S FACING SLOPES OF THE COASTAL 
MOUNTAIN RANGE. 

A GALE EVENT IS CURRENTLY UNDERWAY OVER THE GULF OF TEHUANTEPEC 
DUE TO STRONG HIGH PRES OVER THE GULF OF MEXICO...AND THESE 
CONDITIONS ARE EXPECTED TO LAST FOR ANOTHER 12 HRS. ANOTHER LOW 
IS LOCATED JUST W OF THE NICOYA PENINSULA OF COSTA RICA NEAR 
9N87W BUT CONVECTION IS MEAGER AND DISORGANIZED. THIS FEATURE 
IS ALSO SURROUNDED BY A LARGE AREA OF DRY AIR WHICH WOULD 
PRECLUDE DEVELOPMENT IN THE NEAR TERM.

$$
BERG