000
AXPZ20 KNHC 180933
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAR 18 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 
0845 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE AXIS WAS ANALYZED FROM 03N99W TO 
04N112W TO 07N122W TO 03N140W. SCATTERED MODERATE CONVECTION WAS 
NOTED WITHIN 150 NM N AND 45 NM S OF THE ITCZ AXIS W OF 132W AS 
WELL AS WITHIN 90 NM N OF THE ITCZ AXIS BETWEEN 108W AND 110W. A 
TROUGH IS EMBEDDED IN THE ITCZ FROM 12N119W TO 04N126W. 
SCATTERED MODERATE CONVECTION LIES WITHIN 150 NM EITHER SIDE OF 
THE TROUGH N OF 06N. 

...DISCUSSION...

AN UPPER TROUGH ENTERS THE FORECAST AREA NEAR 32N124W AND 
EXTENDS THROUGH 22N130W TO 17N140W. A BROAD 40-60 KT 
SOUTHWESTERLY JET EXTENDS ACROSS THE AREA E OF THE FRONT AND N 
OF 16N. UPPER LEVEL MOSITURE TRANSPORTED BY THE BROAD JET IS 
GENERATING SCATTERED CIRRUS WITHIN 60 NM EITHER SIDE OF LINE 
FROM FAR NORTHERN BAJA CALIFORNIA NEAR 32N116W TO 23N130W ON THE 
BACK EDGE OF THE STRONG WINDS AS WELL AS ON THE E EDGE OF THE 
JET WITHIN 210 NM EITHER SIDE OF A LINE FROM CENTRAL MEXICO NEAR 
22N102W TO THE NORTHERN END OF A SURFACE TROUGH EMBEDDED IN THE 
ITCZ 10N120W. A WEAK UPPER RIDGE AXIS EXTENDS FROM AN 
ANTICYCLONE NEAR 12N102W THROUGH 12N120W TO 10N140. DIFFLUENCE 
ASSOCIATED WITH THIS RIDGE AXIS IS ENHANCING CONVECTION ALONG 
THE ITCZ W OF THE EMBEDDED TROUGH. THIS CONVECTION IS DESCRIBED 
IN THE ITCZ SECTION. WATER VAPOR IMAGERY SHOWS MOSTLY DRY AIR IN 
THE MID TO UPPER LEVEL IMPLYING SUBSIDENT CONDITIONS OVER MUCH 
OF THE AREA S OF 15N E OF 105W. 

THE BROAD UPPER TROUGH DOMINATING THE NORTHERN PORTION OF THE 
FORECAST AREA WILL BE RELOADED WITH NORTHERN STREAM ENERGY OVER 
THE NEXT FEW DAYS AS AN UPPER LOW CURRENTLY OFF THE U.S. PACIFIC 
NW COAST MOVES INTO THIS BROAD TROUGH AND AMPLIFIES IT. WHILE 
HIGH PRES WILL DOMINATE THE NORTHERN WATERS THROUGH SAT...A COLD 
FRONT ASSOCIATED WITH THIS REINFORCING ENERGY WILL MOVE INTO 
NORTHERN WATERS EARLY SUN MORNING AND IS EXPECTED TO BRING GALE 
FORCE WINDS INTO N WATERS JUST AHEAD OF THE FRONT.

A 1036 MB HIGH CENTER NEAR 34N151W EXTENDS A RIDGE INTO THE 
FORECAST AREA NEAR 32N140W THROUGH 28N120W TO 18N115W. FRESH TO 
STRONG TRADE WINDS LIE S OF THE RIDGE AXIS FROM 05N TO 25N W OF 
125W. THE RIDGE WILL SHIFT SOUTHWARD OVER N WATERS SAT AND 
WEAKEN CONSIDERABLY BY SUN IN ADVANCE OF THE COLD FRONT. THE 
AREA OF TRADES WILL SHIFT S AND DIMINISH A NOTCH OVER THE NEXT 
FEW DAYS IN RESPONSE. FRESH TO STRONG NW WINDS LIE NE OF THE 
RIDGE ALONG THE COAST OF THE BAJA CALIFORNIA PENINSULA. THESE 
WINDS ARE EXPECTED TO SHRINK CLOSER TO THE COAST OVER THE NEXT 
FEW DAYS AND SHIFT S TO THE CENTRAL BAJA CALIFORNIA COAST ON SUN.

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS WILL CONTINUE TO FUNNEL THROUGH 
THE ISTHMUS OF TEHUANTEPEC THROUGH THE FORECAST PERIOD AWAY FROM 
HIGH PRES IN THE GULF OF MEXICO TOWARD LOWER PRES OVER SE 
WATERS. WINDS WILL PULSE TO 25 KT IN THE MORNING HOURS WHEN 
DRAINAGE FLOW THROUGH THE PASS WILL BE AT ITS DIURNAL MAXIMUM. 
THE 0400 UTC ASCAT PASS CONFIRMED WINDS TO 25 KT HERE THIS 
MORNING.

GULF OF PAPAGAYO...THE PRES GRADIENT WILL ALSO REMAIN STRONG 
ACROSS THE GULF OF PAPAGAYO WHERE LITTLE CHANGE IS EXPECTED IN 
THE STRONG NE TO E WINDS CURRENTLY FOUND IN THE GULF THROUGH THE 
REST OF THE PERIOD.

GULF OF PANAMA...THE PRES GRADIENT CONTINUES TO STRENGTHEN 
BETWEEN THE COLOMBIAN LOW AND HIGH PRES OVER CENTRAL AMERICA 
WITH N WINDS EXPECTED TO REACH 25 KT LATER THIS MORNING AND 
REMAIN AT THAT STRENGTH THROUGH THE END OF THE FORECAST PERIOD 
ON SUN MORNING. 

$$
SCHAUER