000
AXPZ20 KNHC 220312
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI APR 22 2011

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 
0315 UTC.

...ITCZ...

AXIS IS CENTERED ALONG 6N77W 7N91W TO LOW NEAR 7N96W 1009 
MB...THEN CONTINUES TO 4N112W TO 4N122W TO 5N140W. SCATTERED 
MODERATE CONVECTION EXISTS FROM 3N-8N BETWEEN 112W-118W...AND
WITHIN 120 NM N OF AXIS BETWEEN 132W-135W.

...DISCUSSION...

ZONAL FLOW ALOFT CONTINUES TO DOMINATE THE AREA N OF 20N...WHILE 
A DEEP LAYER TROUGH EXTENDS FROM THE WESTERN U.S. SW TO NEAR 
28N123W. SATELLITE WATER VAPOR IMAGERY SHOWS MODERATE SUBSIDENCE
WITH ASSOCIATED DRY STABLE CONDITIONS FROM 26N TO 31N TO AS FAR
E AS NW MEXICO. SCATTERED TO BROKEN STRATOCUMULUS TYPE CLOUDS ARE
WITHIN THIS AREA. S OF 20N...UPPER LEVEL RIDGING CONTINUES TO BE 
MAINTAINED BY ACTIVE CONVECTION ALONG THE ITCZ BETWEEN 95W AND 
137W. AN UPPER LEVEL HIGH-LOW COUPLET WAS NOTED WITH CENTERS 
NEAR 15N115W AND 3N124W RESPECTIVELY. NE OF THE RIDGE...A BROAD 
MID TO UPPER LEVEL TROUGH HAS MOVED TO EASTERN MEXICO WITH ITS 
AXIS STRETCHING SSW TO NEAR 11N102W.

AT LOWER LEVELS...MODEST HIGH PRESSURE RIDGING DOMINATES MOST OF 
THE AREA N OF THE ITCZ AND W OF 100W...WITH THE ASSOCIATED 
PARENT HIGH OF 1022 MB CENTERED WELL N OF THE DISCUSSION AREA 
NEAR 40N139W. A RIDGE EXTENDS FROM THIS HIGH SOUTHEASTWARD TO 
30N128W TO NEAR 17N108W. A TIGHT PRES GRADIENT PERSISTS NE OF 
THIS RIDGE WITH TROUGHING LOCATED INLAND OVER CENTRAL MEXICO. AS 
A RESULT OF THIS PRES PATTERN...NW WINDS OF 20-25 KT WINDS ARE 
PRESENT N OF 24N E OF 119W TO THE COAST OF BAJA CALIFORNIA. THESE
WINDS ARE FORECAST TO SHRINK IN AREAL THROUGH THE NEXT 48 HOURS.

NE TO E 20 KT TRADE WINDS SW OF THE RIDGE ARE CONFINED FROM 
8N TO 17N W OF 128W...AND FROM 7N TO 15N BETWEEN 121W AND 128W.
THESE TRADES WILL SHIFT SLIGHTLY WWD DURING THE NEXT 24 HOURS 
THEN EXPAND N AND NE BY 48 HOURS AS NEW HIGH PRES BUILDS ACROSS 
THE AND NW PORTIONS OF THE AREA.

IN THE TROPICS...A RATHER WEAK 1009 MB LOW IS LOCATED NEAR 
7N96W. CONVECTION NOTED EARLIER WITH THIS LOW HAS RECENTLY 
JUST ABOUT ALL DISSIPATED. CONVECTION MAY FORM AGAIN LATER 
TONIGHT INTO FRI MORNING AS THE LOW TRACKS IN A GENERAL WESTWARD 
DIRECTION.

A WEAK SURFACE TROUGH MOVING W ABOUT 10 KT IS ALONG 121W FROM 4N 
TO 12N. DEEP C0CONVECTION EARLIER NOTED WITH THIS TROUGH HAS 
SINCE WEAKENED. GLOBAL MODELS TEND TO GRADUALLY DAMPEN OUT THE 
TROUGH OVER THE NEXT 24 TO 48 HOURS AS IT ALSO TRACKS W.

VERY LONG PERIOD 19-21 SECOND CROSS-EQUATORIAL SW SWELL 
CONTINUES TO PROPAGATE NE ACROSS THE WATERS WITH COMBINED SEAS 
OF 8 FT CONFINED S OF 4N IN THE CENTRAL PORTION. THIS HIGH 
ENERGY SWELL HAS BEGUN TO REACH THE COASTLINES OF SOUTHERN 
CALIFORNIA...MEXICO AND CENTRAL AMERICA TODAY AND SHOULD
ALLOW FOR SEAS HEIGHTS OF 3 TO 6 FT DURING THE NEXT 36 TO 48 
HOURS. THESE VERY LONG PERIOD SWELLS ARE EXPECTED TO POSSIBLY 
PRODUCE VERY HAZARDOUS SURF CONDITIONS ALONG THOSE COASTS.

$$
AGUIRRE