000
AXPZ20 KNHC 201001
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE MAR 20 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 ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

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

NO ITCZ AXIS WAS IDENTIFIED. NO SIGNIFICANT CONVECTION.

...DISCUSSION...

A HIGH AMPLITUDE AND VERY SLOW MOVING DEEP LAYER TROUGH LIES 
OVER THE WESTERN U.S. AND EXTENDS S-SE INTO N CENTRAL MEXICO. A 
STRONG COLD FRONT ASSOCIATED WITH THIS TROUGH LIES OVER N 
CENTRAL MEXICO WHILE A SECONDARY IMPULSE IS DIVING INTO THE BASE 
OF THE TROUGH FROM THE NORTHWEST...AND HAS ENTERED NE PORTIONS 
OF THE AREA...SUPPORTING A WEAK LOW PRES CENTER INTO THE W COAST 
OF BAJA CALIFORNIA NORTE ALONG 29N AND DRAGGING ANOTHER WEAKER 
COLD FRONT WITH IT. FRESH TO STRONG W TO NW WINDS NEAR THIS LOW 
AND S OF THE WEAK FRONT CAN BE FOUND AS FAR AS 360 NM W OF THE 
BAJA PENINSULA N OF 26N BASED ON A 0534 ASCAT PASS. FARTHER SE 
AND AWAY FROM THE CYCLONIC CIRCULATION AROUND THE LOW...COLD AIR 
ADVECTION BEHIND A PREVIOUS FRONTAL PASSAGE IS ALLOWING NWLY 
WINDS TO FUNNEL DOWN THE LENGTH OF THE GULF OF CALIFORNIA...WITH 
A 0350 UTC ASCAT PASS DEPICTING THIS FRESH FLOW INSIDE THE GULF 
BETWEEN 22N AND 26S. SIMILAR WINDS ARE LIKELY OCCURRING WITHIN 
90 NM OF THE W COAST OF THE BAJA PENINSULA S OF 25N. NORTHWEST 
SWELL IN THE PACIFIC CONTINUES TO GENERATE SEAS AS HIGH AS 11 
FEET OFF THE W COAST OF BAJA CALIFORNIA. THESE SEAS WILL 
GRADUALLY SUBSIDE TO 9 FEET OR LESS AS THEY TRAVEL SOUTH OF 15N 
AND WELL OFFSHORE OF MEXICO AND CENTRAL AMERICA BY WED EVENING.

A VERY BROAD AND DEEP LAYERED RIDGE CONTINUES TO DOMINATE MUCH 
OF THE NE PACIFIC S OF 35N AND E OF THE HAWAIIAN ISLANDS THIS 
MORNING...WITH THE SURFACE RIDGE ANCHORED ON A 1026 MB HIGH NEAR 
30N142W...EXTENDING SOUTHEASTWARD TO 23N110W. THIS RIDGE 
CONTINUES TO SUPPORT A LARGE AREA OF FRESH TRADE WINDS TO ITS 
SOUTH FROM FROM 06N TO 20N W OF 127W AND FROM 08N TO 16N BETWEEN 
115W AND 127W. THE SUBTROPICAL HIGH WILL BE WEAKENED AND PUSHED 
EASTWARD BY AN ENCROACHING COLD FRONT OVER THE NEXT FEW DAYS. 
THE AREA OF FRESH TRADES WILL THIN OUT FROM NORTH TO SOUTH TUE 
AND THEN SHRINK WESTWARD THROUGH WED EVENING IN RESPONSE TO 
CHANGES IN THE SUBTROPICAL HIGH.

S OF 20N AND E OF 110W...WEAK WINDS GENIALLY PREVAIL AND A 
CLEARLY DEFINED ITCZ IS NOT PRESENT. A WEAK TROUGH HAS REMAINED 
ACROSS E PORTIONS OF THE AREA FOR THE PAST COUPLE OF DAYS...FROM 
NEAR THE COAST OF NW COSTA RICA TO THE DEEP TROPICS NW OF THE 
GALAPAGOS ISLANDS...WITH PULSING CONVECTION. AN ELONGATED ZONE 
OF SPEED CONVERGENCE S THROUGH SE OF THE SUBTROPICAL RIDGE 
EXTENDS FROM NEAR 10N104W TO 05N140W...AND ISOLATED CLUSTERS OF 
MODERATE TO DEEP CONVECTION ARE FOUND ALONG THIS ZONE.

GAP WINDS...
GULF OF PAPAGAYO...THE PRES GRADIENT BETWEEN RIDGING OVER THE NW 
CARIBBEAN AND LOW PRES ACROSS COLOMBIA AND THE FAR EPAC HAS 
RELAXED ENOUGH FOR WINDS IN THE GULF OF PAPAGAYO TO DIMINISH 
BELOW 20 KT. WINDS MAY PULSE TO 20 KT IN THE EARLY MORNING HOURS 
OF THE NEXT FEW DAYS...WHEN DRAINAGE FLOW OFF THE LAND IS AT A 
MAXIMUM. 

$$
STRIPLING