000
AXPZ20 KNHC 250319
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT APR 25 2009

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...

ITCZ AXIS IS CENTERED ALONG 4N78W 5N90W 5N102W 5N115W 7N125W 
5N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM N OF THE
AXIS BETWEEN 90W-93W AND 60 NM S OF THE AXIS BETWEEN 106W-109W.

...DISCUSSION...

MID/UPPER LEVEL RIDGE EXTENDS FROM THE SW U.S. SW ACROSS 
NORTHWESTERN MEXICO TO NEAR SRN BAJA CALIFORNIA AND SW TO
18N114W TO 11N119W. THIS FEATURE CONTINUES TO PREDOMINATE IN 
THE AREA SEPARATING THE REGION FROM TROUGHS TO ITS E AND NW. THE 
TROUGH TO THE E STRETCHES FROM NE MEXICO SW TO 19N102W TO 
10N105W TO NEAR 06N107W. A STRONG DEEP LAYER TROUGH IS W OF THE 
REGION DIGGING SSE TOWARDS HAWAII. ALTHOUGH THIS CLEARLY DEFINED 
FEATURE IS W OF THE AREA...THE DIFFLUENT PATTERN OBSERVED TO ITS 
ESE IS ENHANCING CONVECTION WITHIN 300 NM SE OF THE TROUGH. DUE 
TO THE CURRENT PLACEMENT OF THE TROUGH AND RIDGE...THE RESULTANT 
MODERATE TO STRONG UPPER FLOW BETWEEN THESE TWO FEATURES IS 
ADVECTING ABUNDANT MID AND UPPER LEVEL CLOUDINESS RELATED TO 
CONVECTION W OF THE AREA UNDER THE DIFFLUENT ENE TO JUST E OF 
140W N OF 15N.

THE TROUGH OVER THE ERN PART OF THE AREA IS ONLY SLIGHTLY 
ENHANCING ITCZ CONVECTION BETWEEN 90W-103W DUE TO MODERATE 
SUBSIDENCE AND STABLE ENVIRONMENTAL CONDITIONS FOUND THERE. THE 
COMBINATION BETWEEN THIS TROUGH AND BROAD MID/UPPER LEVEL 
RIDGING TO ITS E FROM COLOMBIA NW ACROSS MUCH OF CENTRAL AMERICA 
IS ALLOWING FOR HIGH DEBRIS CLOUDINESS FROM ITCZ CONVECTION TO 
ADVECT NNE TOWARDS CENTRAL AMERICA. SPORADIC SMALL CLUSTERS OF 
WEAK CONVECTION ARE NOTED N OF THE ITCZ E OF THE TROUGH TO 83W.

THE MID/UPPER LEVEL RIDGE MENTIONED ABOVE WILL BE NUDGED EWD AND 
GRADUALLY DAMPEN OUT THROUGH SUN AS THE TROUGH AND LOW W OF THE 
AREA LIFT N INTO A LARGER TROUGH THAT DIGS SEWD.

AT THE SURFACE...A WEAK SURFACE TROUGH ENTERS THE AREA THROUGH 
32N131W...AND CONTINUES SW TO W OF THE AREA NEAR 26N140W. MOSTLY 
BROKEN LOW AND MID CLOUDS WITH POSSIBLE WIDELY SCATTERED SHOWERS 
ARE WITHIN 30 NM OF THE TROUGH. THIS TROUGH WILL DISSIPATE 
THROUGH SAT NIGHT.

A 1022 MB HIGH CENTERED NEAR 28N131W EXTENDS A RIDGE SE TO 
22N119W TO 19N109W. HIGH PRES COVERS THE AREA N OF 14N AND W OF 
110W. AS HIGH PRES STRENGTHEN THROUGH SUN...THE PRES GRADIENT 
TIGHTENS OVER THE NE WATERS LEADING TO AN INCREASE IN NW-N WINDS 
(ABOUT 20 KT) NEAR THE BAJA CALIFORNIA COAST...AND ALSO OVER THE
NW WATERS WITHIN THE NEXT 24-48 HRS LEADING TO SE 20-25 KT WINDS
AS LOW PRES...SUPPORTED BY THE STRONG DEEP LAYER TROUGH...FORMS 
W OF THE AREA AND COMBINES WITH THE STRENGTHENING HIGH PRES.

A WEAK SURFACE TROUGH VOID OF ANY DEEP CONVECTION IS ALONG 100W
FROM 4N-7N IS MOVING W 10-15 KT. 

SCATTERED TO BROKEN STRATOCUMULUS CLOUDS ARE NOTED NW OF LINE 
FROM 26N114W TO 20N125W TO 20N137W.

GAP WINDS...
NE WINDS OF 20-25 KT IN THE GULF OF PAPAGAYO ARE FORECAST TO 
WEAKEN TO 20 KT IN 48 HRS WITH SEAS CURRENTLY IN THE 8 TO 10 FT 
RANGE FORECAST TO SUBSIDE TO 8 FT OR LESS.

$$
AGUIRRE