000
AXPZ20 KNHC 012222 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...CORRECTED   
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN APR 01 2012

CORRECTED DESCRIPTION OF CONVECTION ASSOCIATED WITH E PACIFIC 
TROUGH  

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...

THE INTERTROPICAL CONVERGENCE ZONE AXIS EXTENDS FROM 05N120W TO 
04N140W. NO SIGNIFICANT CONVECTION IS NOTED NEAR THE ITCZ AXIS.

A SURFACE TROUGH EXTENDS FROM 10N85W TO 06N92W TO 05N103W. 
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 240 NM S 
OF THE TROUGH BETWEEN 85W-92W.

...DISCUSSION...

A FAIRLY AMPLIFIED AND WINTER TYPE PROGRESSIVE UPPER PATTERN 
REMAINS IN PLACE N OF 25N OVER THE NE PACIFIC. THE LONG WAVE 
TROUGH HAS SHIFTED TO INLAND THE U.S. W COAST THIS AFTERNOON AS 
A LARGE DEEP LAYER RIDGE ADVANCES EWD IN ITS WAKE. WATER VAPOR 
IMAGERY SHOWS MODERATE SUBSIDENCE BEHIND THE TROUGH E OF 126W. 
UPPER LEVEL CENTRAL PACIFIC MOISTURE IS RIDING NEWD ACROSS THE 
CREST OF THE RIDGE...AND SPREADING SEWD INTO THE FAR NRN 
BOUNDARY OF THE DISCUSSION AREA W OF 123W. THE MOISTURE IS 
MATERIALIZING INTO SCATTERED TO BROKEN HIGH LEVEL CLOUDS.

TO THE SE OF THE RIDGE AND TROUGH...A MID/UPPER LEVEL SHORT WAVE 
MOVING EWD ACROSS CENTRAL BAJA CALIFORNIA AND INTO NRN MEXICO
BARELY SUSTAINS A RAPIDLY DISSIPATING COLD FRONT THAT STRETCHES
FROM FAR NW MEXICO NEAR 32N112W SW ACROSS THE CENTRAL BAJA 
CALIFORNIA PENINSULA TO 23N120W AND TO 20N135W. BROKEN PATCHES
OF STRATOCUMULUS CLOUDS MARKING VERY STABLE AND DRY CONDITIONS
BEHIND THE FRONT ARE SEEN NW OF THE FRONT W OF 128W...AND ALSO
WITHIN 180 NM N OF THE FRONT E OF 128W. A 1032 MB SURFACE HIGH 
PRES CENTER IS ANALYZED AT 32N134W. THE FRONT WILL DISSIPATE 
TONIGHT INTO MON...WHILE THE HIGH CENTER SHIFTS EWD. THE 
ASSOCIATED RIDGE WILL DOMINATE THE AREA N OF ABOUT 15N...BUT 
WILL WEAKEN THROUGH MON.

RECENTLY RECEIVED ASCAT DATA FROM NEAR 19 UTC REVEALED FRESH TO 
STRONG N TO NE SURFACE WINDS BEHIND THE FRONT TO 135W...AND NW 
TO N 20 KT WINDS OFF THE NORTHERN AND CENTRAL BAJA CALIFORNIA 
PENINSULA. A BROAD AREA OF FRESH TO STRONG TRADE WINDS IS ALSO
NOTED BY THE SAME ASCAT PASS TO EXIST ALONG THE SRN PERIPHERY
OF THE RIDGE W OF A LINE FROM 06N131W TO 14N126W TO 21N118W.
A FEW SHIP OBSERVATIONS FROM TODAY ALONG WITH EARLIER ALTIMETER 
DATA NOTED COMBINED SEA HEIGHTS IN THE RANGE OF 13 TO 21 FT
OVER THE NE AND N/CENTRAL PORTIONS OF N OF 20N DUE TO LONG 
PERIOD NW SWELLS PROPAGATING SE INTO THE AREA BEHIND THE 
FRONT. COMBINED SEAS TO 9 FT PERSIST S OF 20N IN MIXED SW AND NE 
SWELL...BUT ARE EXPECTED TO BUILD UP TO 12 FT MON AS THE NW SWELL
PRESSES SWD.

OVER THE SW PORTION OF THE AREA...A SHARP DEEP LAYER TROUGH 
CURRENTLY NW OF HAWAII AND WEST OF DEEP LAYER RIDGE MENTIONED
ABOVE WILL SHIFT EWD AND DISPLACING THE RIDGE TOWARDS THE U.S. 
WEST COAST. AN ASSOCIATED COLD FRONT WILL PUSH THROUGH THE N 
CENTRAL PACIFIC...REACHING THE NW CORNER OF THE DISCUSSION AREA 
NEAR 30N140W BY MON AFTERNOON ERODING THE SURFACE HIGH PRES N OF 
THE AREA. THIS WILL ALLOW THE TRADE WINDS TO THE SOUTH AND THE 
MORE NORTHERLY FLOW CLOSER TO THE BAJA COAST TO DIMINISH. THE 
COLD FRONT WILL WEAKEN AS IT MOVES INTO THE NW PART OF THE AREA
FROM 32N132W TO 29N140W BY TUE AFTERNOON. NW SWELLS WILL ALLOW 
FOR SEAS IN THE RANGE OF 8 TO 11 FT TO BE WITHIN THE AREA BOUNDED
FROM 05N TO 20N W OF 105W BY TUE AS YET ANOTHER LARGE BATCH OF 
NW SWELLS POISES TO SPREAD ACROSS THE FAR NW WATERS BEHIND THE 
FRONT. WAVEWATCH GUIDANCES SUGGEST THAT THIS BATCH OF SWELLS 
WILL BUILD SEAS INTO THE RANGE OF 9 TO 12 FT.

FURTHER EAST...CLUSTERS OF SHOWERS AND THUNDERSTORMS PERSIST 
ALONG A STATIONARY TROUGH THAT EXTENDS FROM NEAR CENTRAL
PANAMA TO 06N90W...AND THEN SW T0 04N95W. THE TROUGH MAY 
ACTUALLY BE AN INCIPIENT WEAK MONSOON TROUGH...BUT SCATTEROMETER 
DATA CONTINUE TO SHOW ONLY VERY LIGHT AND OFTEN VARIABLE FLOW S 
OF THE AXIS. CONVECTIVE GROWTH CONTINUES TO BE AIDED BY A BROAD 
NEGATIVELY TILTED UPPER TROUGH EXTENDING FROM 09N85W TO 05N82W 
AND TO 02N80W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS 
WITHIN 240 NM S OF THE TROUGH BETWEEN 85W-92W. LARGE CLUSTERS OF
SCATTERED STRONG CONVECTION ARE OCCURRING FROM 05N TO 08N 
BETWEEN 81W AND 85W MAINLY DUE TO CONVERGENCE OF MODERATE 
NORTHERLY FLOW ACROSS THE PANAMANIAN ISTHMUS AND LIGHT TO 
MODERATE SW FLOW TO THE SOUTH. ALSO...LONG TERM SATELLITE 
IMAGERY INDICATES THAT A POSSIBLE WEAK LOW LEVEL PERTURBATION
MOVED HAS MOVED INTO THAT PORTION OF THE ERN PACIFIC FURTHER
ENHANCING THE DEEP CONVECTION CLUSTERS THERE.

GULF OF CALIFORNIA...A DISSIPATING COLD FRONT PRESSING SE 
ACROSS THE CENTRAL WATERS OF THE GULF. A STRONG PRES GRADIENT 
BETWEEN HIGH PRES BUILDING EWD IN ITS WAKE AND LOW PRES OVER 
NRN MEXICO HAS LEAD TO NW WINDS OF 20 KT OVER THE FAR NRN GULF. 
THESE WINDS WILL INCREASE TO 20 TO 25 KT BY EARLY MON AS THE 
HIGH PRES CENTER N OF THE AREA AND THE ASSOCIATED RIDGE SHIFT
EWD. THE HIGH THEN WEAKENS LATER MON INTO TUE ALLOWING FOR THE
PRES GRADIENT TO SLACKEN...AND THUS DIMINISHING THE WINDS TO 
LESS THAN 20 KT BY EARLY TUE.

$$
AGUIRRE