000
AXPZ20 KNHC 100326
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON MAY 10 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...
AXIS ALONG 06N77W TO 03N92W TO 09N112W TO 05N126W TO 04N140W.  
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM OF 
AXIS 115W-130W.    

...DISCUSSION...
UPPER TROUGH EXTENDS S FROM 32N116W TO 10N132W. TROPICAL 
MOISTURE FROM ITCZ RIDES 65 KT JET CORE NE UNTO BAJA CALIFORNIA 
AND NORTHWESTERN MEXICO AND EVENTUALLY INTO TEXAS. AIR MASS 
REMAINS FAIRLY DRY W OF TROUGH AXIS DUE TO MODERATE TO STRONG 
SUBSIDENCE. DOWNSTREAM...MID TO UPPER LEVEL ANTICYCLONIC GYRE AT 
11N113W HAS BROAD RIDGE EXTEND E TO 107W. GOOD DIFFLUENT FLOW 
ALOFT ENHANCES SCATTERED MODERATE ISOLATED STRONG CONVECTION 
UNDER GYRE.

SHARP UPPER LEVEL TROUGH EXTEND FROM 18N100W TO 02N94W WITH VERY 
DRY SUBSIDING AIR MASS WITHIN 6 DEG OF AXIS DUE TO STRONG 
SUBSIDENCE. FINALLY...SMALL ANTICYCLONIC GYRE AT 04N77W ALSO 
PROVIDING GOOD OUTFLOW FOR SCATTERED CONVECTION ASSOCIATED WITH 
WEAK SURFACE TROUGH PRESENTLY ALONG 77W.

MODEL GUIDANCE HAVING HARD TIME WITH SURFACE TROUGH ORGANIZATION 
AS GFS HAS ADVERSE UPPER LEVEL CONDITIONS OVER IT...WHILE NOGAPS 
AND NAM MAINTAIN IT FAVORABLE WITH WEAK CIRCULATION. ECMWF TAKES 
MIDDLE OF THE ROAD APPROACH KEEPING WEAK TROUGH MEANDERING IN SE 
CORNER OF BASIN. DISAGREEMENT EXTENDS TO POSITION...TIMING AND 
STRENGTH OF SYSTEM. FORECAST MAINTAINS IT AS WEAK TROUGH UNTIL 
MORE FAVORABLE ENVIRONMENT IS NOTED.

AT THE SURFACE...HIGH PRES CENTER 1030 MB AT 34N142W DRIFTING E 
HAS RIDGE EXTEND TO 15N110W. FRESH NE TRADES ON RIDGE SOUTHERN 
PERIPHERY EXPECTED TO EXPAND IN AREA AND INCREASE TO STRONG 
BREEZE WITH SEAS BUILDING TO 11 FT. SIMILARLY WINDS ALONG W 
COAST OF BAJA CALIFORNIA DIG S TO 23N BY END OF FORECAST PERIOD.

GAP WINDS...WITH WEAK TROUGH OVER GULF OF PANAMA AND TIGHT 
GRADIENT ACROSS WESTERN CARIBBEAN...STRONG NE TO E WINDS SEEP 
ACROSS GULF OF PAPAGAYO WITH SEAS TOPPING 10 FT. WINDS EXPECTED 
TO CONTINUE WELL BEYOND END OF FORECAST PERIOD.

WEAK SURFACE TROUGH OVER BAY OF CAMPECHE FUNNELING FRESH N WINDS 
ACROSS ISTHMUS CAUSED SURGE OF STRONG WINDS ACROSS GULF OF 
TEHUANTEPEC WITH 25 KT WINDS BUILDING SEAS TO 8 FT. TROUGH HAS 
MOVED W OUT OF AREA AND WINDS EXPECTED TO DIMINISH BELOW 20 KT 
TONIGHT. SEAS SUBSIDE JUST AS FAST.  

NEW CROSS EQUATORIAL SWELL TRAINS THREATEN E PAC VERY LATE IN 
FORECAST PERIOD AS 10-12 FT COVERING S OF 05N BY END OF FORECAST 
PERIOD...BUT EVENTUALLY SPREADING AS FAR N AS 20N LATER ON.

$$
WALLY BARNES