000
AXPZ20 KNHC 031603
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC WED DEC 03 2008

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 
1500 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...07N78W TO 
05N100W TO 09N122W TO 07N140W. SCATTERED MODERATE CONVECTION 
WITHIN 150 NM S OF AXIS E OF 81W. NUMEROUS STRONG CONVECTION 
WITHIN 75 NM S AND 120 NM N OF AXIS BETWEEN 121W AND 126W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 90 NM 
EITHER SIDE OF LINE FROM 135W AND 139W. 

...DISCUSSION...

A DEEP TROUGH OF LOW PRESSURE...WHICH DOVE INTO THE SOUTHEAST 
U.S. EARLY THIS WEEK...LEFT A STRONG RIDGE OF SURFACE HIGH 
PRESSURE IN ITS WAKE OVER THE CAROLINAS.  WITH THE RIDGE 
EXTENDING SOUTHWARD THROUGH THE EASTERN GULF AND WESTERN 
CARIBBEAN...AN ASSOCIATED...STRONG PRESSURE GRADIENT BOTH ACROSS 
SOUTHERN MEXICO AND CENTRAL AMERICA ARE SUSTAINING TWO 
SIGNIFICANT GAP WIND EVENTS...ONE IN THE GULF OF TEHUANTEPEC AND 
THE OTHER IN THE GULF OF PAPAGAYO. 

A 1219 UTC QUIKSCAT PASS OVER THE GULF OF TEHUANTEPEC REVEALED N 
TO NE WINDS OF 30 TO 40 KT WITHIN ABOUT 90 NM OF THE COAST... 
WITH A BAND OF NEAR 20 KT WINDS FANNING OUT SOUTHWEST FROM THERE 
TO NEAR 11N98W. NOAA WAVEWATCH GUIDANCE SUGGESTS WAVE HEIGHTS OF 
UP TO 9 FT DOWNWIND OF THIS REGION IN MIXED SW AND N SWELL. A 
SHORTWAVE TROUGH MOVING OUT OF THE SOUTHERN ROCKIES HAS ALREADY 
INDUCED...BROAD LOW PRESSURE OVER THE SOUTHERN PLAINS. AS LOW 
PRESSURE CREEPS BACK INTO THE GULF OF MEXICO...THE LARGE-SCALE 
PATTERN WILL NO LONGER SUSTAIN CONDITIONS WHICH FAVOR A GULF OF 
TEHUANTEPEC GAP WIND EVENT. AS A RESULT...MODELS INSIST ON THE 
CURRENT EVENT WINDING DOWN IN EARNEST WITHIN 24 HOURS. HOWEVER...
THE SAME SHORTWAVE TROUGH SHOULD LEAVE A COLD FRONT BEHIND OVER 
THE CENTRAL AND NORTHERN GULF WATERS BY FRI...WITH ANOTHER STRONG
SURFACE RIDGING BUILDING BEHIND IT.  THE CHANGING PATTERN WILL
AGAIN FAVOR THE FORMATION OF ANOTHER GAP WIND EVENT IN THE GULF
OF TEHUANTEPEC WITHIN ABOUT 36 TO 48 HOURS.

DOWNWIND OF THE GULF OF PAPAGAYO...A 1218 UTC QUIKSCAT PASS 
CONFIRMED THE PRESENCE OF NE 20 TO 25 KT WINDS WITHIN ABOUT 60 
NM EITHER SIDE OF 10.5N E OF 88.5W. A BROADER AREA OF 15 TO 20 
KT WINDS SURROUNDS THIS AREA...RUNNING GENERALLY FROM 08N TO 12N 
E OF 91W. THE SURFACE RIDGE EXTENDING INTO THE WESTERN CARIBBEAN 
SUSTAINING THIS EVENT WILL GRADUALLY WEAKEN OVER THE NEXT DAY OR 
TWO...WHICH SHOULD RESULT IN THE END OF THE EVENT WITHIN ABOUT 
24 TO 36 HOURS. HOWEVER...JUST AS WAS THE CASE IN THE GULF...THE
REAPPEARANCE OF STRONG SURFACE HIGH PRESSURE BUILDING FROM THE 
SOUTHERN STATES SOUTHWARD BY FRI SHOULD CAUSE WINDS DOWNWIND OF 
THE GULF OF PAPAGAYO TO REDEVELOP.  NOAA WAVEWATCH GUIDANCE 
INDICATES SEAS OF 8 TO 12 FT OVER MUCH OF THE ABOVE AREA...WITH
NE SWELL LIKELY SPREADING FARTHER W OVER THE NEXT DAY OR TWO 
BEFORE DECAYING FURTHER.

ELSEWHERE...A BAND OF ENHANCED TRADES EXISTS FROM 08N TO 15N W 
OF 130W...A RESULT OF STRONGER-THAN-AVERAGE SUBTROPICAL RIDGING 
JUST NW OF THE AREA. MODELS FORECAST TRADES TO INCREASE A BIT 
FURTHER FROM N TO S W OF 130W OVER THE NEXT 24 HOURS AT THE SAME 
TIME THAT 8 TO 12 FT NW SWELL ARRIVES OVER THE NW PART OF THE 
AREA AND BEGINS TO SPREAD SE. THE SWELL SHOULD RAPIDLY SUBSIDE 
GOING INTO FRI ALONG WITH THE WINDS.

$$
KIMBERLAIN