000
AXPZ20 KNHC 131604
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAR 13 2010

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...

THE ITCZ AXIS WAS CENTERED ALONG 08N77W TO 04N90W TO 05N120W TO 
06N140W.

...DISCUSSION...

MOST SIGNIFICANT FEATURE TODAY IS THE TEHUANTEPEC GAP WIND EVENT 
ONGOING THIS MORNING.  AN EARLIER 0318 UTC ASCAT PASS SHOWED A 
FEW N 35 KT WIND VECTORS.  GIVEN THE UNSTABLE SST-BOUNDARY LAYER 
CONDITIONS...ALL MODELS...GFS...ECMWF...AND NAM...ARE SHOWING 
JUST BELOW GALE FORCE...AND THE TYPICAL DIURNAL CYCLE OF THESE 
EVENTS PEAKING LATE NIGHT-EARLY MORNING...I ADDED THIS AS A GALE 
WARNING FOR 12 UTC.  FORCING FOR THE EVENT COLLAPSES IMMEDIATELY 
AND ALONG WITH THE TYPICAL DIURNAL WEAKENING DURING THE DAY 
MEANS THAT IT SHOULD DROP BELOW GALE FORCE BY THIS AFTERNOON AND 
BELOW OUR 20 KT THRESHOLD BY TOMORROW MORNING.  NO OTHER GAP 
WIND EVENTS ARE ONGOING OR ANTICIPATED TO OCCUR UNTIL TUESDAY 
NIGHT WHEN THE NEXT TEHUANTEPEC EVENT IS LIKELY TO BEGIN.

MODERATE NW TO N WINDS IN THE GULF OF CALIFORNIA ARE ANTICIPATED 
TO WEAKEN TODAY AS THE PRESSURE GRADIENT FORCING SLACKENS.  BUT 
THIS IS SHORT-LIVED AS HIGH PRESSURE REBUILDS JUST WEST OF 
CALIFORNIA AND CYCLOGENESIS OCCURS OVER NORTHERN MEXICO...NEW 
MEXICO AND TEXAS.  NW TO NW 20 TO 25 KT WINDS PARALLELING THE 
GULF SHOULD CONTINUE OVER AT LEAST THE NEXT TWO DAYS.  WEST OF 
BAJA NW TO N 20 TO 25 KT WINDS SHOULD GENERALLY CONTINUE FOR THE 
NEXT DAY BEFORE WEAKENING.

A LARGE AREA OF NE MODERATE TRADEWINDS ARE OCCURRING GENERALLY 
BETWEEN 07N AND 20N W OF 120W THAT WILL CONTINUE WITH LITTLE 
CHANGE FOR THE NEXT COUPLE OF DAYS.  

MOST OF OUR AREA OF RESPONSIBILITY IS COVERED BY SEAS OF AT 
LEAST 8 FT WITH THE HIGHEST UP TO 13 FT OCCURRING W OF BAJA AND 
UP TO 14 FT IN MIXED NW SWELL AND NE WIND WAVES IN THE TRADEWIND 
BELT.  MODERATE NW SWELL WILL CONTINUE TO IMPACT THE WESTERN 
HALF OF OUR AREA OVER THE NEXT FEW DAYS.

IN THE UPPER LEVELS...A SHARP ENE-WSW ORIENTED TROUGH STRETCHES 
FROM 30N118W TO 23N140W AND IS ASSOCIATED WITH A STATIONARY 
SURFACE FRONT ALONG OUR NORTHERN BOUNDARY NEAR 130W.  FARTHER 
SOUTH...AN UPPER HIGH IS CENTERED NEAR 09N104W.  A MODERATE 
UPPER LEVEL JET IS SITUATED A COUPLE HUNDRED NM SOUTH OF THE 
UPPER TROUGH AXIS AND IS ASSOCIATED WITH UPPER LEVEL MOISTURE 
AND SOME HIGH CLOUDINESS BEGIN ADVECTED OVER SOUTHERN BAJA 
CALIFORNIA AND MAINLAND MEXICO.

ONE CURIOUS NOTE IS THE LACK OF SIGNIFICANT ORGANIZED DEEP 
CONVECTION ANYWHERE IN OUR AREA OF RESPONSIBILITY.  EVEN THE 
ITCZ IS SUPPRESSED SUCH THAT NO DEEP CONVECTION BEYOND 
SMALL...TRANSIENT THUNDERSTORMS ARE TO BE SEEN TODAY.  THIS IS 
NOT...HOWEVER...COMPLETELY ATYPICAL OF SPRING CONDITIONS.

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE

$$
LANDSEA