000
AXPZ20 KNHC 011458
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI MAY 01 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 
1430 UTC.

...ITCZ...

ITCZ AXIS IS ALONG 05N77W TO 07N89W TO 03N107W TO 04N120W TO 
03N130W TO 05N140W. NO SIGNIFICANT CONVECTION NOTED. SCATTERED 
SHOWERS/THUNDERSTORMS DOT THE AREA S OF 10N ACROSS THE ENTIRE 
BASIN. 

...DISCUSSION...

EAST OF 110W...
A BROAD MID TO UPPER LEVEL LOW IS SITUATED JUST W OF THE ISTHMUS 
OF TEHUANTEPEC DRAWING DRY UPPER AIR SOUTHWARD OFF THE W COAST 
OF MEXICO W OF PUERTO ANGEL AND ALONG THE E COAST OF THE BAJA 
PENINSULA GIVING THAT AREA CLEAR SKIES TODAY. THIS UPPER LOW IS 
DRAWING TROPICAL MOISTURE N OVER THE GULF OF TEHUANTEPEC AND 
OVER CENTRAL AMERICA INTO THE W CARIBBEAN BUT IS ONLY ABLE TO 
PRODUCE ISOLATED SHOWERS. 

WEST OF 110W...
AN UPPER LEVEL TROUGH COVERS THE AREA N OF 25N BETWEEN 125W AND 
135W WITH A SHEAR AXIS CONTINUING S ALONG 25N128W TO NEAR 
13N140W. A COLD FRONT ASSOCIATED WITH THIS UPPER TROUGH ENTERS 
THE REGION NEAR 32N135W SW TO 29N140W PRODUCING MODERATE SW TO W 
WINDS AND SEAS TO 10 FT W OF THE FRONT. AN UPPER HIGH IS LOCATED 
IN THE TROPICS SE OF THE SHEAR AXIS NEAR 10N118W WITH THE RIDGE 
AXIS EXTENDING N OVER THE CENTRAL BAJA PENINSULA THUS BLOCKING 
THE UPPER TROUGH. UPPER LEVEL MOISTURE FROM THE TROPICS IS BEING 
CHANNELED NNE WITHIN THE SHEAR AXIS AND PRODUCING SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION WITHIN 60/90 NM OF A LINE 
FROM 11N134W TO 18N128W AND DENSE OVERCAST MULTILAYERED CLOUDS 
WITH SCATTERED SHOWERS WITHIN 90/120 NM OF LINE FROM 16N128W 
ALONG 30N120W TO OVER THE N BAJA PENINSULA AND SOUTHERN 
CALIFORNIA. A VERY BROAD UPPER RIDGE ANCHORED W OF THE HAWAIIAN 
ISLANDS DOMINATES THE REMAINDER OF THE REGION KEEPING THE AREA W 
OF 135W UNDER FAIR WEATHER CONDITIONS. 

$$
WALLACE