000
AXPZ20 KNHC 221605
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED APR 22 2009

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.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 05N77W TO 07N86W TO 04N110W TO 
03N126W 04N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 180 
NM OF AXIS BETWEEN 78W AND 87W.  ISOLATED MODERATE WITHIN 180 NM 
N OF AXIS BETWEEN 136W AND 140W.

...DISCUSSION...

GAP WINDS...THE TEHUANTEPECER EVENT PICKED UP AGAIN THIS MORNING 
WITH TWO SHIPS REPORTING 35 KT WINDS...SO GALE WARNINGS WERE 
REINITIATED.  THIS RESTRENGTHENING MAY BE DIURNALLY FORCED AND 
IT IS ANTICIPATED THAT IT WILL DROP BELOW GALE FORCE BY THIS 
AFTERNOON OR EVENING.  COMPLICATING THE SITUATION IS THAT LOCAL 
NE WIND WAVES ARE ALSO INTERACTING WITH A SIGNIFICANT SW SWELL 
ADVECTING IN FROM THE SOUTHERN HEMISPHERE.  THIS GAP EVENT 
SHOULD FADE COMPLETELY BY THURSDAY AFTERNOON.

IN CONTRAST...THE 20 TO 25 KT NE GAP WINDS IN THE GULF OF 
PAPAGAYO SHOULD CONTINUE FOR THE NEXT FEW DAYS AS A STRONG 
SURFACE PRESSURE GRADIENT EXISTS OVER THE CARIBBEAN AND 
SUBTROPICAL NORTH ATLANTIC.

ELSEWHERE...THE NE TRADES SOUTH OF A FAIRLY WEAK 1021 MB HIGH AT 
27N132W ARE PRODUCING WINDS OF ONLY UP TO 20 KT...MAINLY IN THE 
WESTERN PORTION OF OUR REGION.  NEARLY OUR ENTIRE DOMAIN IS 
DOMINATED BY SW SWELL THAT HAS PEAK SIGNIFICANT WAVES HEIGHTS 
CURRENTLY UP TO 10 FT...BUT THESE WILL BE GRADUALLY DECREASING 
OVER THE NEXT FEW DAYS.

A MODEST COLD FRONT IS JUST WEST OF OUR REGION EXTENDING FROM A 
1006 MB LOW AT 33N152W TO 30N142W DOWN TO A DECAYING STATIONARY 
FRONT AT 17N151W.  THIS FRONT SHOULD JUST BRUSH THE NW CORNER OF 
OUR AREA THURSDAY AFTERNOON...BUT IS NOT ANTICIPATED TO BRING 
WITH IT 20 KT OF WIND OR GREATER.  

THERE HAS BEEN A FLAREUP OF DEEP CONVECTION ALONG THE ITCZ EAST 
OF 90W OVER THE LAST DAY OR SO.  HOWEVER...NO SIGNIFICANT 
SURFACE TROUGH OR WAVE IS APPARENT AT THIS TIME.  THE LOW 
LATITUDE AND STRONG VERTICAL SHEAR WOULD LIKELY PRECLUDE ANY 
TROPICAL CYCLONE ASPIRATIONS AT THIS TIME.

IN THE UPPER LEVELS...ZONAL WESTERLIES PREVAIL WITH THE 
SUBTROPICAL JET REACHING SPEEDS OF 90 KT AT 200 MB WITH THE CORE 
OF THE JET ALONG 22N INTO MEXICO.  

$$
LANDSEA