000
AXPZ20 KNHC 311538
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED MAR 31 2010

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...
AXIS IS CENTERED ALONG 04N77W 02N95W 05N123W 03N140W. SCATTERED 
MODERATE CONVECTION IS WITHIN 120 NM OF THE AXIS BETWEEN 79W AND 
83W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS WITHIN 120 
NM EITHER SIDE OF THE AXIS BETWEEN 116W AND 137W.

AN AREA OF SCATTERED MODERATE ISOLATED STRONG CONVECTION IS  
OCCURRING WITHIN 120 NM OF A SURFACE TROUGH EMBEDDED WITHIN THE 
AXIS AND ANALYZED ALONG 08N121W TO 03N124W. 

...DISCUSSION...
A LONG WAVE UPPER LEVEL TROUGH DOMINATES THE NE PACIFIC WITH AN 
AXIS EXTENDING FROM JUST OFFSHORE OF SOUTHERN CALIFORNIA NEAR 
34N124W TO 19N140W THAT CONTINUES MOVING EASTWARD ACROSS THE 
NORTHERN PORTION OF THE DISCUSSION AREA. REMNANTS OF A 
PREVIOUSLY DISSIPATED FRONTAL BOUNDARY ARE ACROSS NW PORTIONS... 
FROM NEAR 30N115W TO BEYOND 21N140W CONTAINING WITHIN IT A NEW 
PULSE OF LARGE NW SWELL ENTERING THE AREA FROM THE NW WITH SEAS 
12 TO 19 FT. SOUTH OF THIS BOUNDARY AND W OF 130W NE WINDS OF 20 
TO 25 KT WERE DEPICTED BY AN EARLIER ASCAT PASS AROUND 0700 
UTC...EXTENDING S TO NEAR 06N. SEA IN THIS REGION WERE BETWEEN 9 
TO 15 FT IN A MIX OF NE WIND WAVES AND LONG PERIOD NW SWELL. SE 
OF THE UPPER LEVEL TROUGH...AN UPPER RIDGE CONTROLS THE AREA W 
OF 105W...WITH AN UPPER HIGH CENTERED NEAR 08N111W. WITHIN THE 
VICINITY OF THE ITCZ...UPPER LEVEL DIFFLUENCE WAS MAINTAINING 
ACTIVE CONVECTION FROM THE EQUATOR TO 11N BETWEEN 116W AND 131W 
FOCUSED ALONG A BROAD LOW LEVEL EASTERLY WAVE. LARGE AMOUNTS OF 
MIDDLE TO UPPER LEVEL MOISTURE ARE BEING ADVECTED NE AND E OVER 
THE UPPER LEVEL RIDGE TO NEAR 110W...WITH A SOUTHERN STREAM 
UPPER LEVEL JET MERGING WITH THE MID-LATITUDE JET EAST OF THE 
UPPER TROUGH OVER SOUTHERN CALIFORNIA. AN ELONGATED MIDDLE TO 
UPPER TROUGH EXTENDS FROM NORTHERN FLORIDA SW ACROSS THE GULF OF 
MEXICO TO A MID-LEVEL LOW NEAR 22N94W...DIGGING VERY SLOWLY SE. 
STRONG SUBSIDENCE IS NOTED ON WATER VAPOR IMAGERY SW OF THE LOW 
ACROSS CENTRAL MEXICO AND OFF THE MEXICO WESTERN COAST N OF 15N 
E OF 112W.

ELSEWHERE AT THE SURFACE...
A 1030 MB HIGH IS LOCATED OVER THE E CENTRAL PACIFIC NEAR 
32N154W WITH A RIDGE AXIS EXTENDING E-SE TO NEAR 24N120W. THE 
PRESSURE GRADIENT ALONG THE SOUTHERN CALIFORNIA COAST AND 
NORTHERN BAJA WAS YIELDING NW TO N WINDS OF 20-25 KT AND 
MAINTAINING SEAS 9 TO 15 FT. OTHERWISE...NE TRADES OF AROUND 20 
KT INDUCED BY THE HIGH AGAINST LOWER PRESSURE ASSOCIATED WITH 
THE ITCZ WERE CONFINED S OF 26N W OF 130W. THE UPPER LEVEL 
TROUGH ACROSS THE NE PACIFIC IS FORECAST TO SHIFT EASTWARD 
REMAINING LARGELY N OF 22N AS IT APPROACHES THE WESTERN U.S. 
LATE WEDNESDAY INTO THURSDAY AND TRAVERSE THE INTERMOUNTAIN WEST 
THURSDAY INTO FRIDAY. A 1008 MB SURFACE LOW CURRENTLY NORTH OF 
THE AREA NEAR 40N129W IS FORECAST TO SLIDE SE AND WEAKEN OVER 
THE NEXT 24 HOURS AS IT APPROACHES THE SOUTHERN CALIFORNIA COAST 
NEAR THE LOS ANGELES BASIN. THIS WILL INDUCE GALE FORCE WINDS IN 
THE WESTERN SEMICIRCLE OF THE LOW AND BRING 25-30 KT NW WINDS 
INTO FAR NE PORTIONS OF THE AREA LATE WEDNESDAY INTO EARLY 
THURSDAY. IT WILL CONTINUE TO DOMINATE THE AREA N OF 27N AND E 
OF 128W WITH FRESH NW WINDS THROUGH FRIDAY...MAINTAINING SEAS 
THERE 12 TO 18 FT THROUGH FRIDAY MORNING. THE HIGH OVER THE E 
CENTRAL PACIFIC WILL NUDGE E-SE ALONG 30N DURING THIS TIME AND 
REINFORCE THE GRADIENT TO THE S AND SE...EXPANDING THE AREA OF 
20-25 KT NE TRADES S OF 25N AND W OF 122W BY EARLY FRIDAY. 

OTHERWISE...LONG PERIOD NWLY SWELL WILL CONTINUE TO MOVE SE 
THROUGH THE ENTIRE AREA THROUGH THE PERIOD.

WINDS IN GULF OF TEHUANTEPEC HAVE DIMINISHED TO A SMALL AREA OF 
20 KT AND ARE EXPECTED BELOW 20 KT BY THIS AFTERNOON. NE GAP 
WINDS THROUGH THE GULF OF PAPAGAYO ARE EXPECTED TO PULSE 
DIURNAL/NOCTURNAL PATTERNS THROUGHOUT THE NEXT FEW DAYS...BUT 
REMAIN AT OR BELOW 25 KT.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
HUFFMAN