000
AXPZ20 KNHC 120920
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE APR 12 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0645 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS WAS ANALYZED FROM AXIS 
FROM 09N84W TO 06N93W TO 08N102W TO 01N112W TO EQUATOR AT 120W 
THEN CONTINUES FROM 04N122W TO 07N130W. SCATTERED MODERATE WITH 
ISOLATED STRONG CONVECTION WAS S OF THE ITCZ AXIS TO 06N BETWEEN 
80W AND 85W. SCATTERED MODERATE CONVECTION E OF THE ITCZ AXIS 
FROM 04N TO 08N BETWEEN 120W AND 127W. ISOLATED MODERATE 
CONVECTION WITHIN 270 NM N AND 150 NM S OF THE ITCZ AXIS BETWEEN 
100W AND 110W.


...DISCUSSION...

THE AXIS OF AN UPPER TROUGH EXTENDS INTO THE FORECAST AREA FROM 
32N136W TO 27N140W. A 50-70 KT WEST-SOUTHWESTERLY JET LIES ON 
THE E SIDE OF THIS TROUGH AND IS TRANSPORTING SOME MID TO UPPER 
LEVEL MOISTURE INTO THE NW PORTION OF THE AREA WHICH IS 
MARKED BY MULTI-LAYERED CLOUDINESS PRIMARILY N OF 23N W OF 129W 
AS A RESULT. A DISSIPATING STATIONARY FRONT ASSOCIATED WITH THIS 
BROAD UPPER TROUGH LIES OVER FAR THE NW PORTION OF THE AREA AND 
SHOULD ERODE THIS MORNING. SUBTROPICAL HIGH PRES IS EMANATING 
FROM A 1034 MB HIGH PRES SYSTEM WELL NW OF THE FRONT NEAR 
40N157W. THIS HIGH PRES WILL WEAKEN AS IT SHIFTS 
EAST-SOUTHEASTWARD WITH LITTLE CHANGE IN THE RIDGING OVER THE 
FORECAST AREA THROUGH WED MORNING. OVERNIGHT WED NIGHT...THE 
HIGH WILL SKIRT JUST N OF THE AREA. FRESH TO STRONG TRADE WINDS 
LIE OVER MUCH OF THE W CENTRAL PORTION OF THE FORECAST AREA 
ACCORDING TO THE 0526 UTC ASCAT PASS AND THE 0228 UTC WINDSAT 
PASS. AS THE HIGH PRES MOVES EASTWARD JUST N OF THE AREA LATE 
WED...LOOK FOR THE AREA OF TRADES TO SHIFT E IN RESPONSE.

THE PRES GRADIENT BETWEEN TROUGHING EXTENDING FROM ALONG THE 
SOUTHERN CALIFORNIA COAST INTO THE NORTHERN GULF OF CALIFORNIA 
AND INTO CENTRAL MEXICO AND A RIDGE AXIS THAT EXTENDS INTO THE 
AREA NEAR 32N127W TO 15N110W IS GENERATING FRESH NW TO N WINDS 
OFF THE W COAST OF BAJA CALIFORNIA AS SEEN IN THE 0528 UTC ASCAT 
PASS. THE EASTWARD MOVING SUBTROPICAL RIDGE WILL TIGHTEN THE 
PRES GRADIENT HERE BY LATE WED...INCREASING WINDS TO 25 KT AND 
ALLOWING THE AREA OF FRESH TO STRONG NW TO N WINDS TO EXPAND TO 
WITHIN 450 NM OF BAJA CALIFORNIA.

AN ANTICYCLONE ALOFT NEAR 17N105W EXTENDS A RIDGE AXIS SE TO 
05N100W AND SW TO 04N124W. THE INTERSECTION OF THE ITCZ AND EACH 
OF THESE RIDGE AXES LIES WITHIN MAXIMA OF LOW TO MID LEVEL 
MOISTURE ACCORDING TO PRECIPITABLE WATER SATELLITE IMAGERY. 
CONVECTION LIES IN EACH OF THESE REGIONS AND IS DESCRIBED IN THE 
ITCZ SECTION ABOVE. FARTHER E...MODERATE UPPER DIFFLUENCE 
BETWEEN THIS ANTICYCLONE AND AN UPPER TROUGH THAT EXTENDS 
THROUGH HISPANIOLA AND PANAMA TO NEAR 05N80W IS ENHANCING 
CONVECTION ON THE E EDGE OF THE ITCZ ALONG THE COAST OF COSTA 
RICA.

GAP WINDS...
GULF OF PAPAGAYO...THE 0342 UTC ASCAT PASS CONTINUES TO SHOW 
FRESH NE TO E WINDS IN THE GULF OF PAPAGAYO. THESE WINDS WILL 
CONTINUE TO PULSE TO 20 KT THE NEXT COUPLE OF DAYS WITH SEAS 
REMAINING JUST BELOW 8 FT. THE LARGEST AREAL EXTENT OF THE 20 KT 
WINDS WILL BE IN THE EARLY MORNING HOURS WITH THE AID OF 
NOCTURNAL DRAINAGE FLOW.
 
GULF OF TEHUANTEPEC...A WEAK COLD FRONT IN THE GULF OF MEXICO 
WILL PASS THROUGH THE ISTHMUS OF TEHUANTEPEC THIS EVENING AND 
BRIEFLY BRING FRESH TO STRONG N WINDS TO THE GULF OF TEHUANTEPEC 
ENDING WED AFTERNOON.

$$
SCHAUER