000
AXPZ20 KNHC 292205
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN MAR 29 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 6N80W 2N91W 2N104W 2N115W 4N125W 
6N140W. SCATTERED STRONG CONVECTION EXISTS FROM 6N-9N BETWEEN
133W-136W.

...DISCUSSION...

DEEP LAYER TROUGH STRETCHES FROM THE WRN U.S. INTO THE AREA
THROUGH 32N124W...AND EXTENDS TO AN ELONGATED UPPER LEVEL CUT-OFF
CYCLONIC CIRCULATION NEAR 25N137W AND W OF THE AREA THROUGH 
24N140W. N OF THE TROUGH RATHER PRONOUNCED N FLOW IS PRESSING 
SWD INTO THE DISCUSSION AREA. AT THE SURFACE...THE LEADING EDGE 
OF THIS SURGE IS MARKED BY A COLD FRONT THAT EXTENDS ROUGHLY 
ALONG 32N BETWEEN 115W-131W. NE WINDS OF 20-25 KT ARE FUNNELING 
INTO THE NRN AND NW SECTIONS OF THE AREA WITH STRONGER WINDS OF 
GALE FORCE OVER WATERS TO THE N. THE LOW IS FORECAST TO QUICKLY 
MOVE TO FAR NE PART OF THE AREA THROUGH TUE AS THE TROUGH PULLS 
TO WELL E OF THE AREA...AND BECOME ABSORBED INTO A SHORTWAVE 
TROUGH THAT DROPS SE ACROSS THE SW U.S. HIGH PRES...BOTH ALOFT 
AND AT THE SURFACE WITH THE PARENT HIGH CENTER N OF THE 
AREA...THEN DOMINATES THE NORTHERN PORTION OF THE AREA 
MAINTAINING N-NE WINDS IN THE GENERAL RANGE OF 20-25 KT WITH 
SEAS BUILDING TO 10-14 FT IN A N SWELL N OF 28N BETWEEN 
121W-129W. UPPER FLOW PATTERN BECOMES RATHER ZONAL N OF 
18N BY TUE WITH LITTLE CHANGE IN SURFACE WEATHER CONDITIONS 
ANTICIPATED.

TO THE S OF THE TROUGH...BROAD ANTICYCLONIC FLOW IS EVIDENT 
ALOFT WITH ITS ASSOCIATED CENTER LOCATED NEAR 4N107W. A MEAN
RIDGE AXIS EXTENDS FROM THE CENTER NW TO 14N115W...THEN N TO
20N116W TO 27N118W. ANOTHER RIDGE EXTENDS FROM THIS CENTER 
NE TO ACROSS SRN NICARAGUA INTO THE FAR SW CARIBBEAN SEA.
MODERATE SUBSIDENCE IS MAINTAIN RATHER DRY STABLE CONDITIONS S 
OF 18N E OF 120W WITH ONLY NARROW LINES OF LOW CLOUDS WITH 
ISOLATED SHOWERS SEEN HERE...WITH THE EXCEPTION OF A SMALL AREA 
OF SCATTERED SHOWERS AND TSTMS WITHIN 45 NM OF LINE FROM 8N82W 
TO 5N85W ENHANCED BY A MID/UPPER LEVEL TROUGH THAT EXTENDS S 
FROM THE SW CARIBBEAN SEA ACROSS PANAMA TO 6N85W. LITTLE CHANGE
IS EXPECTED WITH THESE CONDITIONS OVER THE NEXT 48 HRS.

TO THE W OF THE ANTICYCLONIC FLOW AREA...A RATHER SHARP MID/UPPER
LEVEL TROUGH EXTENDS FROM 13N140W SE TO 9N137W TO S OF THE 
EQUATOR AT 131W. A DIFFLUENT UPPER FLOW PATTER E OF THE TROUGH 
IS SUSTAINING THE AREA OF SCATTERED STRONG CONVECTION NOTED 
ABOVE UNDER ITCZ. THIS CONVECTION SHOULD LIKELY PERSIST IN THAT 
GENERAL AREA THROUGH THE NEXT 24-48 HRS AS THE TROUGH IS 
FORECAST TO ONLY SLOWLY PROGRESS EWD. UPPER LEVEL MOISTURE 
INDUCED FROM THIS CONVECTION IS MERGING WITH A LARGE SWATH OF 
UPPER LEVEL MOISTURE THAT STREAMS ENE INTO THE AREA FROM 7N TO 
21N W OF 133W. THE MOISTURE IS THEN BEING ADVECTED ENE TOWARDS 
BAJA CALIFORNIA AND WRN MEXICO AS IT RIDES IN FAST WSW UPPER 
FLOW THAT IS SQUEEZED IN BETWEEN THE UPPER TROUGH AND THE 
ANTICYCLONIC FLOW TO ITS S. A SURFACE RIDGE EXTENDS INTO THE 
AREA THROUGH 32N135W AND REACHES TO 22N123W. HIGH PRES COVERS 
THE AREA N OF 17N W OF 120W. PATCHES OF STRATOCUMULUS CLOUDS WITH
POSSIBLE ISOLATED SHOWERS ARE MOVING WSW IN MODERATE NE FLOW N 
OF 16N AND W OF 120W.

GULF OF TEHUANTEPEC N WINDS OF 20 KT ARE FORECAST TO DIMINISH IN 
ABOUT 6 HRS AS WRN GULF OF MEXICO WINDS VEER TO THE SE.

$$
AGUIRRE