000
AXPZ20 KNHC 231010
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON APR 23 2012

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

MONSOON TROUGH NO LONGER EVIDENT. ITCZ AXIS EXTENDS FROM 03N89W 
TO 05N104W TO 04N122W TO BEYOND 04N140W. SCATTERED MODERATE 
ISOLATED STRONG WITHIN 180 NM EITHER SIDE OF AXIS BETWEEN 91W 
AND 108W. SCATTERED MODERATE TO STRONG FROM 07N TO 12N BETWEEN 
116W AND 124W. 

...DISCUSSION...

A WEAKENING MIDDLE/UPPER LEVEL LOW LIES OFF THE W COAST OF BAJA 
CALIFORNIA NEAR 30N118W. THIS LOW IS LIFTING NORTHWARD ON THE 
LEADING EDGE OF A DEEP LAYER TROUGH CENTERED OVER THE PORTION OF 
THE DISCUSSION AREA N OF 23N ALONG 140W. FARTHER EAST...A 
BLOCKING UPPER RIDGE LIES OVER NORTHERN MEXICO AND EXTENDS INTO 
THE SOUTHWESTERN UNITED STATES. BROADLY DIFFLUENT UPPER LEVEL 
FLOW IS FOUND IN MUCH OF THE REGION BETWEEN 10N AND 20N W OF 
110W AND N OF 15N E OF 110W...SOUTH OF THE DEEP LAYER TROUGH AND 
THE UPPER RIDGE. IN THE DEEP TROPICS...AN UPPER LEVEL CYCLONIC 
CIRCULATION IS CENTERED NEAR 01N108W AND A RIDGE AXIS LIES TO 
ITS NE...EAST OF 110W. 

A 1019 MB HIGH IS CENTERED NEAR 23N117W AND DRIFTING SLOWLY E. 
THIS HIGH AND THE RESULTING PRES GRADIENT HAS BEEN WEAKENED BY 
THE TROUGHING ALOFT. THIS HAS RESULTED IN TRADE WINDS S OF THE 
HIGH AT LESS THAN 20 KT OVER THE FORECAST AREA. A COLD FRONT 
ASSOCIATED WITH THE DEEP LAYER TROUGH EXTENDS FROM 30N132W TO 
23N140W. SCATTERED LIGHT TO MODERATE SHOWERS ARE ALONG THE 
FRONT...WHILE NW TO N WINDS TO 20 KT PREVAIL WEST OF THE FRONT. 
THESE CONDITIONS WILL CONTINUE OVER NW WATERS BEHIND THIS SLOW 
MOVING COLD FRONT OVER THE NEXT FEW DAYS...WITH SEAS BUILDING TO 
12 FT IN NW SWELL. 

THE DEEP LAYER TROUGH OVER NW WATERS IS EXPECTED TO CUT OFF FROM 
THE NORTHERN STREAM AND APPROACH N WATERS BY WED. THE UPPER JET 
ON THE LEADING EDGE OF THIS TROUGH WILL INTENSIFY AS THE TROUGH 
AMPLIFIES. THE REAR RIGHT QUADRANT OF THIS JET WILL LIE NEAR THE 
MOISTURE RICH REGION NEAR THE ITCZ BY LATE TUE. THIS AREA WILL 
BE FAVORED FOR CONVECTION. THE MODEL GUIDANCE SUGGESTS THAT A 
WEAK SURFACE TROUGH MAY ALSO DEVELOP NEAR THE ITCZ. THIS SHOULD 
ALLOW FOR THE PRES GRADIENT TO INCREASE ENOUGH TO SUPPORT FRESH 
NE WINDS PRIMARILY FROM 08N TO 14N BETWEEN 120W AND 130W BY 
EARLY TUE.

GAP WINDS...
GULF OF TEHUANTEPEC...HIGH PRES OVER THE WESTERN GULF OF MEXICO 
BEHIND A STRONG LATE SEASON COLD FRONT HAS TIGHTENED THE PRES 
GRADIENT ACROSS SOUTHERN MEXICO RESULTING IN WINDS TO GALE FORCE 
THROUGH THE GULF OF TEHUANTEPEC. NORTH-NORTHEASTERLY GALE FORCE 
WINDS TO 40 KT ARE EXPECTED THERE THIS MORNING AND WILL DIMINISH 
BELOW GALE FORCE BY TUE AFTERNOON.

GULF OF PAPAGAYO...THE COLD FRONT THAT USHERED IN THE HIGH PRES 
OVER THE WESTERN GULF OF MEXICO THAT INCREASED THE PRES GRADIENT 
OVER THE GULF OF TEHAUNTEPEC WILL DO THE SAME OVER THE GULF OF 
PAPAGAYO OVERNIGHT TONIGHT AFTER THE COLD FRONT MOVES INTO COSTA 
RICA. WINDS ARE EXPECTED TO REMAIN FRESH TO STRONG DOWNWIND OF 
PAPAGAYO THROUGH THE END OF THE FORECAST PERIOD ON TUE AFTERNOON 
AND WILL LIKELY CONTINUE INTO WEDNESDAY.

GULF OF PANAMA...FRESH NORTHERLY WINDS FROM THE CARIBBEAN WILL 
FUNNEL INTO THE GULF OF PANAMA BEHIND THE AFOREMENTIONED COLD 
FRONT BY TUE MORNING. 

$$
STRIPLING