000
AXPZ20 KNHC 310319
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC MON JAN 31 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 03N77W TO 
03N96W TO 08N121W TO 07N140W. NO SIGNIFICANT DEEP CONVECTION.

...DISCUSSION...
AT THE SURFACE...THE SEMI-PERMANENT NE PACIFIC HIGH IS CENTERED 
AT THE BORDER OF OUR AREA AT 31N 131W WITH A CENTRAL PRESSURE OF 
1028 MB.  THE GRADIENT BETWEEN THIS HIGH AND THE LOW PRESSURE OF 
THE ITCZ ARE GENERATING FRESH BREEZE NE TRADEWINDS.  THESE ARE 
ANTICIPATED TO CHANGE LITTLE OVER THE NEXT TWO DAYS.  IN THE 
NORTHWEST CORNER OF OUR AREA...SURFACE WINDS ARE ANTICIPATED TO 
BRIEFLY REACH 20 KT FROM THE SOUTH ON MONDAY AHEAD OF A COLD 
FRONT.  HOWEVER...FORCING OF THE COLD FRONT SHOULD MOVE 
NORTHEASTWARD ON TUESDAY...PREVENTING THE FRONT FROM REACHING 
140W SOUTH OF 32N.

AS A LOW PRESSURE SYSTEM DEVELOPS EAST OF THE ROCKIES OVER THE 
NEXT DAY OR SO...THE SURFACE GRADIENT WILL BE ENHANCED ALONG 
BOTH SIDES OF BAJA CALIFORNIA.  NW WINDS HAVE CURRENTLY REACHED 
20 KT WEST OF BAJA AND SHOULD DO THE SAME IN THE GULF OF 
CALIFORNIA BY MONDAY MORNING.  THIS PATTERN WILL BE SHORT-LIVED 
WITH WINDS DIMINISHING BELOW OUR 20 KT THRESHOLD BY TUESDAY 
MORNING WEST OF BAJA AND BY TUESDAY NIGHT IN THE GULF OF 
CALIFORNIA.  IN THE LONGER RANGE...A VERY STRONG GULF OF 
CALIFORNIA WIND EVENT...PERHAPS OF GALE-FORCE INTENSITY...IS 
LIKELY TO BEGIN ON WEDNESDAY.

A SURFACE TROUGH EMBEDDED IN THE ITCZ ALONG 123W BETWEEN 06N AND 
12N IS PRODUCING SOME CONVECTION...THOUGH THE COVERAGE AND DEPTH 
HAS DIMINISHED OVER THE LAST FEW HOURS.  THIS FEATURE IS 
ANTICIPATED TO MOVE TOWARD THE WEST OVER THE NEXT COUPLE OF 
DAYS...THOUGH FURTHER TROPICAL DEVELOPMENT IS UNLIKELY DUE TO 
STRONG VERTICAL SHEAR AND ONLY MODEST CONVECTIVE INSTABILITY.

NW SWELL BLANKETS NEARLY OUR ENTIRE AREA OF RESPONSIBILITY. ALL 
OF THIS LONG-PERIOD SWELL SHOULD REMAIN UNDER 12 FEET 
SIGNIFICANT WAVE HEIGHTS...WITH THE EXCEPTION OF N OF 21N W OF 
138W WITH UP TO 15 FT.

GAP WINDS...A WEAK GULF OF PAPAGAYO GAP WIND EVENT CONTINUED 
THIS EVENING WITH NE TO E WINDS OF 20 KT...THOUGH NO IN-SITU 
OBSERVATIONS WERE AVAILABLE.  THIS SHOULD CONTINUE AT THE SAME 
STRENGTH THROUGH TUESDAY NIGHT.

THE GULF OF PANAMA GAP WINDS NOTED EARLIER FADED BELOW OUR 20 KT 
CRITERIA THIS EVENING.

THE NEXT STRONG GAP WIND EVENT...IN THE GULF OF TEHUANTEPEC... 
SHOULD COMMENCE WEDNESDAY NIGHT AND WILL LIKELY REACH GALE FORCE.

ALOFT...
A LARGE UPPER LEVEL TROUGH IS LOCATED ALONG 28N137W TO 21N140W.  
WHILE THIS IS NOT ASSOCIATED WITH ANY SIGNIFICANT SURFACE 
WEATHER AT THIS TIME...STRONG SOUTHWESTERLY WINDS ALOFT ARE 
INHIBITING ANY FURTHER DEVELOPMENT OF THE AFOREMENTIONED SURFACE 
TROUGH.

$$
LANDSEA