000
AXPZ20 KNHC 231644 AAA
TWDEP 

TROPICAL WEATHER DISCUSSION...AMENDED
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU OCT 23 2008

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1530 UTC.

UPDATED TO INCLUDE TROPICAL DEPRESSION SEVENTEEN-E

...SPECIAL FEATURES...
TROPICAL DEPRESSION SEVENTEEN-E HAS FORMED NEAR 13.1N 104.9W AT 
23/1615 UTC OR ABOUT 360 NM SOUTH OF MANZANILLO MEXICO MOVING N 
AT 5 KT. MAXIMUM SUSTAINED WIND SPEED IS 30 KT WITH GUSTS TO 40 
KT. ESTIMATED MINIMUM CENTRAL PRESSURE IS 1008 MB. SEE LATEST 
NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 
KNHC FOR MORE DETAILS. THE DEPRESSION IS MAINTAINING A WELL 
DEFINED BUT RATHER SMALL AREA OF MODERATE TO STRONG CONVECTION 
FROM 13N-16N BETWEEN 104W-107W. THIS SYSTEM IS FORECAST TO 
BECOME A TROPICAL STORM LATER TODAY AND TONIGHT BEFORE STEADILY 
WEAKENING AS AN UPPER TROUGH DIGS SOUTH...INCREASING THE 
VERTICAL WIND SHEAR. 

...TROPICAL WAVES...
TROPICAL WAVE IS ALONG 84W N OF 04N MOVING W 10-15 KT. A LARGE 
AREA OF SCATTERED MODERATE CONVECTION...PARTIALLY ASSOCIATED 
WITH THIS FEATURE...IS OVER PORTIONS OF CENTRAL AMERICA AND THE 
WESTERN CARIBBEAN. SIMILAR WEATHER IS EVIDENT NEAR THE BASE OF 
THE WAVE EMBEDDED WITHIN THE ITCZ.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 09N84W TO 07N95W TO 11N104W TO 
08N131W TO 09N140W. SCATTERED MODERATE CONVECTION FROM 03N TO 
08N BETWEEN 78W AND 84W. SCATTERED MODERATE TO STRONG WITHIN 180 
NM N AND 120 NM S OF AXIS BETWEEN 115W AND 125W.  
 
...DISCUSSION...

QSCAT PASS AROUND 12Z TODAY SHOWED 20 KT N WINDS IN THE GULF OF 
TEHUANTEPEC...DUE TO THE ENHANCED N FLOW ON THE W PERIPHERY OF 
LOW PRES OVER THE GULF OF MEXICO. WINDS ARE EXPECTED TO RAMP UP 
TO GALE FORCE TONIGHT AS A COLD FRONT PUSHES SE INTO THE BAY OF 
CAMPECHE WITH HIGH PRES SURGING S OVER MEXICO. MODEL GUIDANCE 
IS IN GOOD AGREEMENT IN INDICATING A RATHER SHORT-LIVED 
GALE...EXPECTED TO SUBSIDE FRI NIGHT. LOOKING FURTHER 
AHEAD...THE COMBINATION OF A POTENT COLD FRONT AND A LARGE 
STRONG CANADIAN HIGH PRES AREA WILL CAUSE A STRONGER GAP 
EVENT...POSSIBLY STORM FORCE...EARLY NEXT WEEK. 

THE TIGHT PRES PATTERN OVER THE SW U.S. IS RESULTING IN STRONG N 
WINDS FUNNELING THRU THE N PORTION OF THE GULF OF CALIFORNIA. 
THERE IS A WIDE RANGE OF SFC WIND REPORTS IN THE AREA RANGING 
FROM 10 KT TO NEAR GALE FORCE. BASED ON THE LARGE SCALE PRES 
PATTERN IT APPEARS THAT WINDS SHOULD QUICKLY DIMINISH TONIGHT 
AND TOMORROW. 

AN OCCLUDED LOW PRES SYSTEM PRODUCING GALE FORCE WINDS IS 
LOCATED JUST NW OF THE DISCUSSION ZONE.  THIS FEATURE IS CUT OFF 
AND IS NOW MOVING SW...AWAY FROM THE ZONE...STEERED BY THE E 
PERIPHERY OF AN UPPER HIGH. WHILE WINDS ARE NOT EXPECTED TO BE 
AN ISSUE OVER THE NW CORNER...ASSOCIATED NW SWELLS WILL ELEVATE 
SEAS TO 10 FT OVER THE NEXT FEW DAYS. 

AN UPPER DIFFLUENT PATTERN...BETWEEN A PAIR OF HIGHS NEAR 
13N134W AND OVER THE NW CARIBBEAN AND A LARGE TROUGH EXTENDING 
THROUGH N MEXICO AND WELL S INTO THE TROPICS....IS ENHANCING AN 
AREA OF SCATTERED MODERATE TO STRONG CONVECTION WITHIN THE ITCZ 
FROM 08N-13N BETWEEN 116W-123W. 

$$
CANGIALOSI