000
AXPZ20 KNHC 171543
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC MON MAY 17 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 
1515 UTC.

...TROPICAL WAVES...
TROPICAL WAVE ALONG 84W FROM 04N-09N MOVING W AT 10 KT. NORTHERN 
HALF OF WAVE UNDER FAVORABLE MOIST ANTICYCLONIC FLOW ALOFT 
WHICH ENHANCES ITS SCATTERED DEEP CONVECTION BUT MIGHT DRIFT 
INTO MORE ADVERSE ENVIRONMENT WITHIN NEXT 36-48 HRS.

TROPICAL WAVE ALONG 113W FROM 05N-13N REMAINS UNDER MOIST 
ENVIRONMENT BUT IS AT THE EDGE OF DRY AIR MASS.  ASSOCIATED 
NUMEROUS MODERATE AND SCATTERED STRONG DEEP CONVECTION IS WITHIN 
180 NM OF AXIS.  WITH SOUTHERLY ANTICYCLONIC FLOW ALOFT...WAVE 
COULD CONTINUE STRENGTHENING UNLESS DRY AIR INTRUDES INTO IT. 

...ITCZ...
AXIS ALONG 08N78W TO 07103W TO 10N111W TO 07N127W TO 07N140W.  
ISOLATED MODERATE CONVECTION WITHIN 360 NM OF AXIS E OF 100W.  
ISOLATED MODERATE TO STRONG CONVECTION WITHIN 120 NM S OF AXIS 
FROM 119W-125W.

...DISCUSSION...
UPPER LEVEL TROUGH EXTENDS FROM 32N115W TO 21N126W THEN W TO 
21N140W.  CONFLUENT WINDS WITHIN 120 NM W OF TROUGH AXIS 
MAINTAIN MODERATE TO STRONG SUBSIDENCE AND DRY AIR...BUT 
UPSTREAM ANTICYCLONE AT 23N140W BRING ABUNDANT MOISTURE OVER  
ITS CREST INTO E PAC ELSEWHERE N OF 23N W OF TROUGH AXIS.

UPPER LEVEL ANTICYCLONE GYRE AT 10N102W WITH BROAD RIDGE AXIS 
EXTENDING ALONG 09-10N FROM 131W TO COSTA RICA.  RIDGE IN GOOD 
POSITION TO ENHANCE DEEP CONVECTION ALONG ITCZ AND ADVECT ITS 
MOIST CONVECTIVE DEBRIS W OF 110W ALL THE WAY ACROSS INTO MEXICO 
RIDING ON JET STREAM BRANCH WITH 95 KT CORE. 

ELSEWHERE AT THE SURFACE...
BROAD RIDGE WITH CENTER WELL W OF BASIN MAINTAINS AREA OF FRESH 
TRADES FROM 09N-15N W OF 120W DIMINISHING IN COVERAGE TUE THEN 
GROWING AGAIN AS RIDGE EXTEND FURTHER E.  VERY WEAK COLD FRONT 
JUST ENTERED NW CORNER OF BASIN WILL SHIFT N OF AREA TONIGHT AND 
ITS ASSOCIATED FRESH SW BREEZE FALLS BELOW 20 KT.

AS RIDGE MOVES E...PRES GRADIENT WITH 1004 MB LOW PRES OVER 
SOUTHERN CALIFORNIA PRODUCE FRESH NW BREEZE WITHIN 120 NM OF W 
COAST OF BAJA CALIFORNIA EARLY WED.

CROSS EQUATORIAL SW SWELL SEEP INTO BASIN S OF 09N W OF 110W 
TODAY AND EXTEND FARTHER E TO 95W.  

$$
WALLY BARNES