000
AXPZ20 KNHC 151555
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 15 2010

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.

...TROPICAL WAVES...
WEAK TROPICAL WAVE ALONG 93W FROM 03N-09N MOVING W AT 10 KT. 
SCATTERED DEEP CONVECTION WITHIN 210 NM W AMD 90 NM E OF AXIS.
CONVECTION UNDER INCREASING N-NE WIND SHEAR NOT EXPECTED TO 
DEVELOP ANY CYCLONIC ORGANIZATION WITHIN NEXT TWO DAYS. 

...ITCZ...
AXIS ALONG 04N77W TO 09N114W TO 08N133W TO 07N140W.  SCATTERED 
MODERATE TO ISOLATED STRONG CONVECTION FROM WITHIN 120 NM N AND 
75 NM S OF AXIS E OF 87W.  ISOLATED MODERATE CONVECTION WITHIN 
120 NM N OF AXIS FROM 110W-113W.

...DISCUSSION...
UPPER LEVEL TROUGH EXTENDS FROM 32N112W TO 25N115W KEEP VERY DRY 
AIR MASS N OF 20N ACROSS ENTIRE BASIN WITH HELP OF UPSTREAM MID 
TO UPPER LEVEL RIDGE ALONG 125W N OF 23N.  MOISTURE SWATH RIDES 
ON QUASI ZONAL WESTERLY 95 KT JET CORE RUNNING ALONG 20N ACROSS 
ENTIRE E PAC.  

WELL ANCHORED MID TO UPPER ANTICYCLONE CENTERED AT 10N103W WITH 
E-W RIDGE EXTENDING ALONG 10N MAINTAINS GOOD OUTFLOW ENVIRON FOR 
WEAK 1010 MB SURFACE LOW PRES CENTER PRESENTLY AT 09N103W.  
ALTHOUGH LOW PRES LACKS ANY SIGNIFICANT DEEP CONVECTION AT THIS 
TIME...MODEL GUIDANCE AGREES ON WESTWARD TO DRIFT ALONG 09N-10N 
UNDER RIDGE ENHANCING ITS CHANCES OF DEVELOPING SOME CYCLONIC 
ORGANIZATION.

FINALLY...UPPER LEVEL TROUGH OVER WESTERN CARIBBEAN DIGS S INTO 
EXTREME SE CORNER OF E PAC WITH SMALL AREA OF DIFFLUENT FLOW 
ENHANCING SCATTERED MODERATE ISOLATED STRONG CONVECTION E OF 
87W. 

ELSEWHERE AT THE SURFACE...HIGH PRES CENTER 1025 MB AT 33N138W 
HAS RIDGE EXTEND SE TO 15N110W.  AREA OF FRESH TO STRONG TRADE 
WINDS ON ITS SOUTHERN PERIPHERY SHRINKS IN SIZE AND STRENGTH AS 
HIGH PRES WEAKENS AND IS FORCED SE BY APPROACHING COLD FRONT DUE 
TO ENTER E PAC LATE SUN.  NE SWELL FROM TRADES W OF 120W SUBSIDE 
BY LATE MON AND CROSS EQUATORIAL SW SWELL...NOW E OF 120W... 
TAKE OVER BY MON AS DOMINATING TRAIN THROUGHOUT MOST OF BASIN.

GAP WINDS...FRESH NE-E WINDS THROUGH GULF OF PAPAGAYO E OF 90W 
EXPECTED TO DIMINISH BELOW 20 KT IN 18 HOURS AS SOURCE OF STRONG 
WINDS IN WESTERN CARIBBEAN IS CUT OFF. 

NOTE...TODAY MARKS BEGINNING OF 2010 EASTERN NORTH PACIFIC 
HURRICANE SEASON WHICH RUNS THROUGH NOVEMBER 30.  ON AVERAGE... 
SIXTEEN TROPICAL STORMS FORM EVERY YEAR...NINE OF WHICH WILL 
BECOME HURRICANES WITH 4 REACHING MAJOR STATUS.  FIRST TROPICAL 
STORM THIS SEASON WILL BE NAMED AGATHA.

$$
WALLY BARNES