000
AXPZ20 KNHC 041617
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE MAR 04 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 
1445 UTC.
 
...ITCZ...
ITCZ AXIS ALONG...6N78W  3N83W  1N102W  7N118W  5N132W  6N140W.  
ISOLATED MODERATE WITHIN 60 NM OF AXIS E OF 90W.

...DISCUSSION...
UPPER LEVELS...
BROAD WELL ANCHORED ANTICYCLONE REMAINS STEADY IN POSITION AT 
18N89W WITH LITTLE...IF ANY...FURTHER ELY MOVEMENT.  UPPER LEVEL 
TROUGH THAT FORCED IT HERE HAS WEAKENED AND APPEARS TO BE LAYING 
FLAT N OF 20N AS RIDGE EXTENSION TO THE W GETS STRONGER WITH 
SECOND ANTICYCLONE DEVELOPING AT 8N128W.  TROUGH AXIS FROM FROM 
N CENTRAL MEXICO TO 18N114W TO AND SECOND UPSTREAM TROUGH FROM 
32N115W TO 19N140W MERGING AND FLATTENING.  VERY DRY AIR MASS 
ALONG TROUGH AXIS DUE TO MODERATE TO STRONG SUBSIDENCE.  MINOR 
AMOUNT OF TRPCL MOISTURE ADVECTED NORTHEASTWARD BY BROAD RIDGE 
CROSSING CENTRAL MEXICO INTO GULF OF MEXICO FEEDING COLD FRONT 
IN THAT BASIN.  

AT THE SURFACE...
HIGH PRES 1032 MB AT 36N134W HAS RIDGE EXTEND SE TO 15N110W 
LIMITING CLOUD VERTICAL DEVELOPMENT UNDER IT.  
 
GULF OF CALIFORNIA NW WINDS DIMINISH BELOW 20 KT THIS AFTERNOON.

GULF OF TEHUANTEPEC...DIFFERENCES IN MODEL GUIDANCE UNDERMINE 
CONFIDENCE IN ISSUED DEVELOPING GALE WARNING THIS AFTERNOON... 
BUT SUDDEN BURST OF VERY STRONG WINDS IS EXPECTED DUE TO PASSAGE 
OF COLD FRONT ACROSS BAY OF CAMPECHE.  CULPRIT MIGHT BE THE 
SHALLOWNESS OF COLD AIR MASS MAKING IT HARDER FOR MODELS TO 
IDENTIFY BOUNDARY AND ABILITY TO CROSS ISTHMUS GAP.  BURST OF 
GALE WINDS WILL BE SHORT LIVED AND OF QUICK DEVELOPMENT AND 
DEMISE.  AS OF LATEST RUN MODELS GRAVITATE TOWARDS ISSUANCE OF 
WARNING. 
 
$$
WALLY BARNES