000
AXPZ20 KNHC 302157
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON MAR 30 2009

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 2130 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N82W 2N93W 2N104W 2N120W 6N130W
6N140W. SCATTERED MODERATE CONVECTION IS BETWEEN 120-180 NM 
N OF THE AXIS W OF 137W.

...DISCUSSION...

SATELLITE WATER VAPOR IMAGERY SHOWS A DEEP LAYER TROUGH 
STRETCHING FROM THE WRN U.S. INTO THE AREA THROUGH 32N122W...AND 
EXTENDING TO A DIFFUSING UPPER CYCLONIC CIRCULATION NEAR 26N132W 
AND EXITING THE AREA THROUGH 25N140W. N OF THE TROUGH RATHER 
PRONOUNCED NLY FLOW IS PRESSING SWD INTO THE DISCUSSION AREA. AT 
THE SURFACE...A STRONG SURGE OF NW TO N WINDS IS RESULTING GALE 
FORCE N OF THE AREA OFF CALIFORNIA WITH MOMENTUM OF THESE WINDS 
CARRIED S INTO THE NE PART OF THE AREA AS NE WINDS OF 20-25 KT N 
OF 27N BETWEEN 121W AND 131W. THE LOW SHOULD DISSIPATE TONIGHT. 
THE TROUGH WILL PULL TO WELL E OF THE AREA THROUGH WED. THESE 
WINDS THEN BECOME MORE NW TO N WITHIN 48 HRS AS LOW PRES 
DEEPENING OVER THE SW U.S. COMBINES WITH HIGH PRES OVER THE 
DISCUSSION AREA. EXPECT SEAS TO BUILD UP TO 14 FT IN THIS AREA 
ON WED. THE HIGH PRES...WHICH IS PRESENT BOTH ALOFT AND AT THE 
SURFACE WITH A RIDGE INTO THE AREA THROUGH 32N135W TO 26N129W TO 
NEAR 20N117W...HAS ITS PARENT HIGH CENTER OF 1037 MB NW OF THE 
AREA NEAR 37N144W. THE PRES GRADIENT ATTRIBUTED TO THIS FEATURE 
IS ALLOWING FOR NE WINDS OF 20-25 KT WITH SEAS IN THE 8-10 FT 
RANGE ELSEWHERE N OF 13N W OF 132W. UPPER FLOW PATTERN BECOMES 
RATHER ZONAL N OF 18N TUE AND WED WITH LITTLE CHANGE IN SURFACE 
WEATHER CONDITIONS ANTICIPATED. LATEST VISIBLE SATELLITE IMAGERY 
IS SHOWING PATCHES OF BROKEN STRATOCUMULUS CLOUDS WITH POSSIBLE 
ISOLATED SHOWERS MOVING WSW IN THE NE FLOW N OF LINE FROM 
25N115W TO 22N127W TO 18N140W.

TO THE S OF THE TROUGH...BROAD ANTICYCLONIC FLOW IS EVIDENT 
ALOFT WITH ITS ASSOCIATED CENTER LOCATED NEAR 10N110W. A RIDGE
AXIS EXTENDS FROM THE ANTICYCLONIC CENTER NW TO 14N113W...THEN 
TO 20N115W...AND N TO 28N115W. ANOTHER RIDGE EXTENDS FROM THIS 
CENTER NE TO OVER CENTRAL MEXICO. MODERATE SUBSIDENCE IS 
MAINTAINING RATHER DRY STABLE CONDITIONS S OF 17N E OF 120W WITH 
ONLY NARROW LINES OF LOW CLOUDS WITH ISOLATED LIGHT SHOWERS 
NOTED THERE. THE TAIL END OF A MID/UPPER LEVEL TROUGH OVER THE
FAR WRN CARIBBEAN SEA STRETCHES S TO BORDER OF COSTA RICA AND 
PANAMA. THESE CONDITIONS ARE EXPECTED TO CHANGE VERY LITTLE OVER 
THE NEXT 48 HRS.

TO THE W OF THE ANTICYCLONIC FLOW AREA...A RATHER SHARP MID/UPPER
LEVEL TROUGH EXTENDS FROM 12N133W SE TO 6N130W TO S OF THE
EQUATOR AT 129W. A DIFFLUENT UPPER FLOW PATTERN E OF THE TROUGH 
IS SUSTAINING THE AREA OF SCATTERED MODERATE CONVECTION 
DESCRIBED ABOVE UNDER ITCZ. STRONGER CONVECTION IS JUST W OF THE
AREA. THIS CONVECTION SHOULD LIKELY PERSIST IN THAT GENERAL AREA 
THROUGH THE NEXT 24-36 HRS AS THE TROUGH IS FORECAST SLOWLY MOVE
E AND DAMPEN OUT. UPPER LEVEL MOISTURE INDUCED FROM THIS 
CONVECTION IS MERGING WITH A LARGE SWATH OF UPPER LEVEL MOISTURE 
THAT IS STREAMING ENE INTO THE AREA FROM 12N TO 23N W OF 134W. 
THE MOISTURE PLUME THEN TURNS MORE NE AROUND THE NRN PERIPHERY
OF THE LARGE ANTICYCLONE S OF THE TROUGH MENTIONED EARLIER...AND
IS BEING DRIVEN BY A STRONG JET STREAM BRANCH THAT ENTERS THE 
AREA FROM 21N140W TO 24N130W TO 28N120W TO ACROSS NORTHERN BAJA 
CALIFORNIA AND NRN MEXICO. THE MOISTURE IS BEING ADVECTED TOWARDS
BAJA CALIFORNIA AND WRN MEXICO AS SCATTERED TO BROKEN HIGH 
CLOUDS.

$$
AGUIRRE