000
AXPZ20 KNHC 141515
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU MAY 14 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 
1500 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...06N77W TO 
07N105W TO 09N120W TO 04N140W. SCATTERED MODERATE WITH ISOLATED 
STRONG CONVECTION IS WITHIN 60 NM OF THE POINT 06N81W. SCATTERED 
MODERATE TO STRONG CONVECTION IS WITHIN 90 NM OF THE POINT 
05.5N89W. SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS 
WITHIN 60 NM OF THE POINT 06.5N97W AND THE POINT 07N101.5W.
SCATTERED MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN THE 
AREA 120 NM EITHER SIDE OF THE ITCZ FROM 106W TO 115W. SCATTERED 
MODERATE WITH ISOLATED STRONG CONVECTION IS WITHIN 60 NM OF THE 
POINT 09.5N120W.

OTHER CONVECTION...SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN THE AREA N OF 12.5N FROM 93W TO 95W.

...DISCUSSION...

LARGE MAINLY UPPER LEVEL TROUGH IS OVER THE AREA NORTH OF A LINE 
FROM 14N140W TO 18N120W TO BEYOND 25N100W. THE TROUGH EXTENDS 
NORTH TO A WEAK RIDGE ALONG THE NORTHERN PART OF THE AREA NORTH 
OF A LINE FROM 27N140W TO BEYOND 32N128W. AN ILL DEFINED 
CYCLONIC CIRCULATION IS NEAR 24N132. THIS FEATURE EXTENDS OVER A 
DEEPER LAYER OF THE ATMOSPHERE OVER MEXICO NORTH OF 30N AND THE 
SOUTHWEST UNITED STATES. THIS FEATURE IS FORECAST TO PERSIST 
THROUGH THE NEXT SEVERAL DAYS.  A SMALL AREA OF BROKEN MIDDLE 
LEVEL CLOUDS IS FROM 21N TO 23N FROM 121W TO 131W OTHERWISE THE 
MIDDLE AND UPPER LEVELS ARE DRY AND CLOUD FREE IN THIS AREA. 
ONLY SCATTERED THIN HIGH CLOUDS ARE NORTH OF THE TROUGH. THE 
LOWER LEVELS ARE ALSO MOSTLY CLEAR IN THIS AREA.

SOUTH OF THE TROUGH A LARGE PLUME OF DEEP LAYER MOISTURE WITH 
AREAS OF MULTI LEVEL CLOUDS IS OBSERVED. WEST OF 110W THE 
MOSITURE IS CONFINED TO NORTH OF THE ITCZ HOWEVER EAST OF 110W 
NORTHERLY FLOW OVER THE ITCZ BRINGS SOME OF THE CLOUDINESS 
SOUTH OF THE ITCZ BUT THE CLOUDS DISSIPATE RATHER QUICKLY AS 
THEY MOVE TOWARD THE EQUATOR. ENHANCED CONVECTION IS OBSERVED IN 
THIS CLOUDY AREA MAINLY FROM 107W TO 115W SOUTH OF 14N. ALSO 
CONVECTION WITHIN THE ITCZ IS SOMEWHAT ACTIVE EAST OF 117W.

A WEAK MAINLY UPPER TROUGH IS LOCATED NORTH OF THE ITCZ EAST OF 
95W. SUBSIDENCE IS OBSERVED OVER CENTRAL AMERICA BUT DIFFLUENT 
NORTHERLY FLOW OVER THE OCEAN IS ENHANCING CONVECTION IN AND 
SOUTH OF THE GULF OF TEHUANTEPEC REGION. 

WEAK SURFACE RIDGE IS NORTH OF 12N WEST OF 100W. ELSEWHERE A 
BROAD TROUGH IS ANALYZED AT THE SURFACE.

$$
LL