000
AXPZ20 KNHC 221558
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT SEP 22 2007

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 
1500 UTC.

...SPECIAL FEATURE...
TROPICAL STORM IVO AT 1500 UTC AT 21.3N 112.7W...OR ABOUT 235 NM 
SW OF SRN TIP OF BAJA CALIFORNIA MEXICO...MOVING N-NE AT 5 
KT. MAXIMUM SUSTAINED WIND 50 GUSTS TO 60 KT.  ESTIMATED MINIMUM 
CENTRAL PRESSURE 997 MB.  UPPER LEVEL CYCLONIC VORTEX JUST AT 
34N122W MAINTAINS A STRONG HOSTILE SWLY SHEAR OVER IVO MAKING IT 
HARD TO DEVELOP OR EVEN MAINTAIN ITS PRESENT INTENSITY... 
ALTHOUGH DEEP CONVECTION AROUND CENTER HAS INCREASED WITHIN LAST 
4-6 HRS.  IVO EXPECTED TO DRIFT CLOSER TO BAJA CALIFORNIA AND 
THE POSSIBILITY OF TROPICAL STORM ADVISORIES MIGHT BE NECESSARY 
LATER ON THIS AFTERNOON OR TONIGHT.  REFER TO LATEST NHC 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/WTPZ22 KNHC 
FOR MORE DETAILS. 
  
...TROPICAL WAVES...
TRPCL WAVE ALONG 100W N OF 6N MOVING W 10 KT.  MODERATE NELY 
SHEAR LIKELY TO INCREASE AS WAVE MOVES W AND CHANCES OF ANY 
DEVELOPMENT ARE VERY SLIM.  MOST CONVECTION IS FROM 11N TO 14N
W OF AXIS SHOWS EFFECT OF SHEAR ALOFT.  

...ITCZ...
ITCZ AXIS ALONG  8N78W  13N120W  13N140W.  SCATTERED MODERATE 
CONVECTION WITHIN 90 NM N OF AXIS FROM 94W-120W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION WITHIN 45 NM OF AXIS E OF 
96W.

...DISCUSSION...
DECAYING REMNANTS OF TROPICAL DEPRESSION 13-E NEAR 17N128W... 
OVER 1200 NM W-SW OF SRN TIP OF BAJA CALIFORNIA CONTINUES MOVING 
W PRESENTS NO THREAT TO LAND AREAS.  WITH DECREASING W SHEAR 
ABOVE IT...A BURST OF CONVECTION DEVELOPED EARLY THIS MORNING.  
NEVERTHELESS CLUSTER LIKELY TO ENCOUNTER VERY HOSTILE INCREASING 
NW WINDS ALOFT WHICH LIKELY SPELL SYSTEMS DEMISE.  

ENTIRE E PAC W OF 110W UNDER ABSOLUTE CONTROL OF LARGE AMPLITUDE 
UPPER LEVEL TROUGH FROM 34N122W TO 5N133W.  MODERATE SUBSIDENCE 
W OF TROUGH AXIS KEEPS DRY AND STABLE AIR MASS SUPPRESSING 
CONVECTION.  ON THE OTHER HAND...TROUGH ADVECTING PLENTY OF 
TROPICAL MOISTURE DEBRIS FROM ITCZ NW INTO WRN MEXICO BUT 
LIMITED LOW LEVEL UPLIFT AVAILABLE.  

AT THE SURFACE...ONLY ONE TROPICAL WAVE WHICH APPEARS DOOMED TO 
PRESENT STATUS WITHOUT CHANCES OF DEVELOPMENT APPEAR ON 1200 UTC 
ANALYSIS.  

HIGH PRES CENTER NW OF E PAC MAINTAINS MODERATE NE TRADES OVER 
NW CORNER OF BASIN.  CROSS EQUATORIAL SWELLS AFFECTING E PAC S 
OF 10N E OF 125W EXPECTED TO REMAIN THROUGH NEXT COUPLE OF DAYS. 

$$
WALLY BARNES