000
AXPZ20 KNHC 131013
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAY 13 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 0900 UTC.

...ITCZ...
ALONG 08N78W 08N82W 10N95W 04N109W 05N119W 06N130W 03N140W. 
SCATTERED MODERATE SHOWERS ISOLATED STRONG CONVECTION WITHIN 180 
NM N OF AXIS FROM 125W-133W.

...DISCUSSION...
MID TO UPPER LEVEL TROUGH EXTEND FROM 32N113W TO 26N123W TO 
30N140W.  FAIRLY DRY AIR MASS WITHIN 120 NM OF AXIS BUT PRETTY 
MOIST ELSEWHERE N OF TROUGH BROUGHT IN BY 90 KT JET CORE 
ROUNDING TROUGH BASE.  ON S AND SE SIDE OF TROUGH...85 KT WINDS 
ADVECTING SWATH ABUNDANT TRPCL MOISTURE ACROSS ENTIRE E PAC INTO 
SRN HALF OF BAJA CALIFORNIA SPILLING INTO N AND CENTRAL MEXICO.

S OF TROUGH BROAD MID-UPPER RIDGE MAINTAINS GOOD ANTICYCLONIC 
FLOW S OF 20N W OF 118W.  UPPER LEVEL ANTICYCLONIC CIRCULATION 
CENTER AT 07N134W HELPS WITH CONVECTIVE DEBRIS OUTFLOW FOR 
SURFACE TROUGH NOW ALONG 131W FROM 04N TO 10N.  TROUGH SHOULD 
FADE AWAY W OF 140W WITHIN NEXT 48 HRS. 

SECOND WELL-DEFINED MID TO UPPER LEVEL ANTICYCLONIC CIRCULATION 
CENTER OVER SRN MEXICO CONTINUES BRINGING TRPCL MOISTURE FROM 
SOUTH AMERICA CONTINENT INTO E PAC THEN TURN IT NORTH INTO GULF 
OF MEXICO.  DEFORMATION ZONE BETWEEN THE TWO ANTICYCLONES ALONG 
115W WITH ITS ATTENDANT DIFFLUENT FLOW FAILS TO DEVELOP ANY 
SIGNIFICANT CONVECTION DUE TO DRYNESS OF SURFACE AIR MASS.  ONLY 
MINOR ISOLATED CONVECTION IS DETECTED BY SATELLITE.  

AT THE SURFACE...
WEAKENING HIGH PRES 1029 MB AT 34N137W HAS RIDGE EXTEND TO 
12N106W.  GLOBAL MODELS DIMINISH STRONG NE TRADES FROM 08N-15N
W OF 128W WITHIN NEXT 24 HRS AS HIGH PRES IS FORCED E BY 
INCOMING COLD FRONT WELL N OF BASIN.  LONG FETCH N FRESH WINDS 
BUILD LARGE N SWELL E OF 125W WHICH SUBSIDE BY END OF FORECAST 
PERIOD.  

WEAK TROUGH ALONG 131W HAS FAVORABLE UPPER LEVEL ENVIRON AS IT 
TRAVEL W OF 140W WITHIN NEXT 48 HRS.  SCATTERED MODERATE 
ISOLATED STRONG CONVECTION ASSOCIATED WITH TROUGH BOUNDARY. 

SECOND SURFACE TROUGH ALONG 104W HAS MINOR ISOLATED CONVECTION 
AS IT MOVES AWAY FROM FAVORABLE UPPER FLOW.

$$
WALLY BARNES