000
AXPZ20 KNHC 231553
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SUN SEP 23 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 DEPRESSION IVO AT 22.1N 111.4W...OR 100 NM W-SW OF CABO 
SAN LUCAS MEXICO...AT 1500 UTC MOVING ENE AT 4 KT.  MAXIMUM 
SUSTAINED WIND 25 GUSTS TO 35 KT.  ESTIMATED MINIMUM CENTRAL 
PRESSURE 1007 MB.  IVO CONTINUES UNDER STRONG SWLY SHEAR WINDS 
AND THE EFFECTS ARE FELT IN THE DECREASE OF ITS DEEP CONVECTION
AND ASSOCIATED WINDS.  IT IS EXPECTED THAT IVO BECOMES A REMNANT 
LOW PRES WITHIN 12 HRS AND BE DISSIPATED WITHIN 72 HRS.  SEE  
LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP2/ 
WTPZ22 KNHC FOR MORE DETAILS.
  
...TROPICAL WAVES...
TROPICAL WAVE ALONG 104W FROM 5N TO 15N MOVING W 10-15 KT HAS 
SCATTERED CONVECTION MOSTLY ASSOCIATED WITH ITCZ AXIS.  ALTHOUGH 
PRESENT WINDS ALOFT NOT UNFAVORABLE AND NOT LIKELY TO BE IN ITS 
IMMEDIATE PROJECTED PATH...NOT DEVELOPMENT OF CYCLONIC 
ORGANIZATION IS EXPECTED. 

TROPICAL WAVE ALONG 82W JUST ENTERED E PAC N OF 5N MOVING W 15 
KT HAS SCATTERED MODERATE CONVECTION MAINLY OVER COSTA RICA AND 
NICARAGUA.  WAVE CARRIES PLENTY OF TROPICAL MOISTURE BUT NELY 
WINDS ALOFT TOO STRONG TO ENHANCE DEEP CONVECTION AT THIS TIME.  

...ITCZ...
ITCZ AXIS ALONG  6N77W  6N83W  10N90W  12N114W  14N122W  11N133W 
12N140W.  SCATTERED MODERATE WITHIN 120 NM S OF AXIS E OF 79W 
ALONG COLOMBIAN COAST.  SCATTERED MODERATE WITHIN 180 NM N OF 
AXIS AND WITHIN 60 NM S OF AXIS FROM 110W TO 117W. 

...DISCUSSION...
LARGE AMPLITUDE UPPER LEVEL TROUGH DIGS INTO E PAC FROM 32N117W 
TO 13N135W WITH VERY DRY STABLE AIR MASS NW OF AXIS LIMITING 
CONVECTIVE DEVELOPMENT.  STRONG WINDS AROUND ITS BASE CURTAILING 
DEEP CONVECTION ON ALL SYSTEMS UNDER ITS PATH...IVO AND REMNANTS 
OF T.D. 13-E.  

SHARP RIDGE DOWNSTREAM ALONG 110W IS CAUGHT BETWEEN ABOVE 
MENTIONED TROUGH AND CYCLONIC VORTEX OVER NE MEXICO TRAPPING 
MOST OF ITS MOISTURE CHANNELING IT INTO NWRN MEXICO...ARIZONA 
AND NEW MEXICO.  CONVERGING AIR FLOW ALOFT BETWEEN RIDGE AND 
VORTEX DRIES PART OF ITCZ AND NRN HALF OF TRPCL WAVE ALONG 104W 
CURTAILING DEEP CONVECTION.

SECOND UPPER LEVEL RIDGE FROM YUCATAN TO 10N102W MAINTAINS 
STRONG NE WINDS ALOFT S OF 10N E OF 100W ALSO PREVENTING 
DEVELOPMENT OF DEEP CONVECTION ALONG TRPCL WAVE. 

AT THE SURFACE...
HIGH PRES CENTER 1028 MB WELL NW OF E PAC MAINTAINS MODERATE 
FLOW OF NE TRADES N OF 20N W OF 125W WITH MINOR NE SWELL TRAINS 
ENCROACHING INTO NW CORNER OF BASIN.  

LARGER SLY SWELLS CROSS EQUATOR FROM S PAC AFFECTING E PAC S OF 
12N FROM 90W TO 125W. 

$$
WALLY BARNES