000
AXPZ20 KNHC 171518
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI FEB 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1330 UTC.

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

THE MONSOON TROUGH EXTENDS FROM 02N90W TO 06N104W TO 02N120W TO 
02N125W. THE ITCZ EXTENDS FROM 02N125W TO BEYOND 03N140W. 
SCATTERED MODERATE CONVECTION LIES WITHIN 120 NM EITHER SIDE OF 
AXIS E OF 104W AND WITHIN 210 NM S OF AXIS BETWEEN 107W AND 125W.

...DISCUSSION...

A BROAD UPPER TROUGH EXTENDS FROM A LOW OVER SOUTHERN ARIZONA 
NEAR 23N111W THROUGH 20N120W TO ANOTHER WEAKER LOW NEAR 15N140W. 
A BELT OF SCATTERED CIRRUS LIES AHEAD OF THE TROUGH AND IS 
CENTERED FROM 10N130W THROUGH CENTRAL MEXICO. THE NORTHERN UPPER 
LOW WILL MIGRATE EASTWARD INTO TEXAS ON SAT...DISTANCING ITSELF 
FROM THE WEAKER LOW OVER WESTERN WATERS. THIS WESTERN LOW WILL 
PHASE WITH A NEW TROUGH DROPPING S ALONG THE CALIFORNIA COAST BY 
SUN. 

AT THE SURFACE...THE RIDGE AXIS EXTENDING FROM 1033 MB HIGH PRES 
CENTERED NEAR 35N145W SOUTHEASTWARD TO NEAR 16N105W IS DICTATING 
THE PREVAILING FRESH TO STRONG NORTHEASTERLY WINDS ACROSS MUCH 
OF THE AREA BETWEEN THE RIDGE AND THE ITCZ/MONSOON TROUGH. THE 
AFOREMENTIONED UPPER LOW OVER WESTERN WATERS IS ASSOCIATED WITH 
A SURFACE TROUGH FROM 11N117W TO 05N114W. THE 0450 UTC ASCAT 
PASS SHOWS FRESH NE WINDS EXTEND EASTWARD TO THE AREA N OF THIS 
TROUGH. THIS TROUGH LIES UNDER AN AREA OF BROAD UPPER DIFFLUENCE 
ALONG A RIDGE AXIS FROM AN ANTICYCLONE CENTERED NEAR 07S131W TO 
A COL NEAR 06N110W. THIS DIFFLUENCE IS ENHANCING SCATTERED 
MODERATE CONVECTION FROM 06N TO 13N BETWEEN 107W AND 116W E OF 
THE TROUGH. 

FRESH NW TO N WINDS LIE JUST N OF THE RIDGE AXIS NEAR THE COAST 
OF CABO CORRIENTES MEXICO WHERE THE PRES GRADIENT IS TIGHT 
BETWEEN THE RIDGE AND TROUGHING OVER CENTRAL MEXICO ASSOCIATED 
WITH THE UPPER LOW CENTERED OVER SOUTHERN ARIZONA. THIS GRADIENT 
WILL REMAIN STRONG THROUGH SAT MORNING AND THEN DIMINISH AS THE 
REMAINS OF THE LOW ARE EJECTED EASTWARD AND ITS ASSOCIATED COLD 
FRONT MOVES INTO THE WESTERN GULF OF MEXICO.

AS THE NEW UPPER TROUGH DROPS S ALONG THE CALIFORNIA COAST EARLY 
ON SUN...THE REMNANTS OF ITS ASSOCIATED SURFACE COLD FRONT WILL 
MOVE INTO NW WATERS BRINGING FRESH NW TO N WINDS AND NW SWELL TO 
12 FEET. 

...GAP WINDS...

NE TO E WINDS AT 20 KT THROUGH THE GULF OF PAPAGAYO WILL 
CONTINUE UNTIL SAT AFTERNOON WHEN A COLD FRONT MOVES INTO THE 
GULF OF MEXICO DISTURBING THE PRES GRADIENT BETWEEN HIGH PRES TO 
THE N AND LOWER PRES ALONG THE MONSOON TROUGH TO THE S. THE 
STRONGEST WINDS WILL OCCUR DURING EARLY MORNING HOURS WITH THE 
AID OF DRAINAGE FLOW. 

THE NORTHERLY WINDS OF 20 KT THAT WERE PASSING INTO THE GULF OF 
PANAMA YESTERDAY APPEAR TO BE GRADUALLY DIMINISHING...WITH THE 
0308 UTC ASCAT PASS ONLY SHOWING ONE BARB OF 20 KT WINDS IN THE 
AREA. 

LOOKING AHEAD...EXPECT INCREASING WINDS AND SEAS ACROSS THE GULF 
OF TEHUANTEPEC BY SUN AFTERNOON AS A STRONG COLD FRONT MOVES 
ACROSS THE WESTERN GULF OF MEXICO. THE NORTHERLY WINDS THROUGH 
THE PASS INTO THE GULF OF TEHUANTEPEC MAY BRIEFLY REACH GALE 
FORCE SUN EVENING.
 
$$
SCHAUER