000
AXPZ20 KNHC 071604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON JAN 07 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 
1500 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE ALONG...8N78W 5N97W 7N113W 
7N140W. SCATTERED MODERATE WITHIN 120 NM N OF AXIS FROM 118W TO 
133W. 

...DISCUSSION...
UPPER LEVELS...
DEEP LAYER LONGWAVE TROUGH FROM 32N110W DIGS SW TO 14N130W WITH 
VERY DRY AIR MASS WITHIN 240 NM FROM AXIS.  WEAK JTST 75 KT 
CARRY WHAT LITTLE MOISTURE RISE FROM ITCZ NE INTO CENTRAL MEXICO 
ALONG CREST OF MID/UPPER LEVEL RIDGE LOCATED JUST DOWNSTREAM. 
RIDGE AXIS FROM 17N104W TO 5N119W.  

ANOTHER UPPER LEVEL TROUGH EXTENDS FROM CYCLONIC VORTEX AT 
15N99W SW TO 3N103W.  AIR MASS ALSO DRY ALONG TROUGH AXIS DUE TO 
MODERATE TO STRONG SUBSIDENCE.  BROAD MID/UPPER LEVEL RIDGE 
COMPLETES PICTURE OVER E PAC COVERING FROM SOUTH AMERICA ACROSS 
CENTRAL AMERICA INTO GULF OF MEXICO.  CONDITIONS MODERATELY DRY 
UNDER RIDGE WITH ONLY MINOR TROPICAL MOISTURE SWATH ADVECTED 
BETWEEN RIDGE AND TROUGH IN 45 KT JET CORE. 

AT THE SURFACE...
COLD FRONT DENTS NRN EDGE OF BASIN FROM 32N118W 29N124W 
29N130W.  STRONG W-NW WIND N OF SYSTEM WILL DIMINISH WITHIN 24 
HRS AS FRONT MOVES INLAND.  NE TRADES W OF 120W CAUSED BY HIGH 
PRES 1025 MB CENTERED AT 27N144W WILL REMAIN THROUGH FORECAST 
PERIOD.

WEAKENING GULF OF PAPAGAYO GAP WINDS EXPECTED TO WEAKEN WITHIN 
24 HRS AND GET BELOW 20 KT WITHIN 48 HRS.

$$
WALLY BARNES