000
AXPZ20 KNHC 010916
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU JAN 01 2009

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 
0900 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...04N77W TO 
05N95W TO 08N110W TO 08N120W TO 07N130W TO 09N140W. NUMEROUS 
MODERATE ISOLATED STRONG CONVECTION BETWEEN 75 AND 240 NM N OF 
AXIS BETWEEN 133W AND 140W.

...DISCUSSION...

AFTER NEARLY 36 HOURS OF GALE CONDITIONS NEAR AND DOWNWIND OF 
THE GULF OF TEHUANTEPEC...A QUIKSCAT PASS YESTERDAY MORNING 
INDICATED THAT WINDS HAD DIMINISHED BELOW GALE FORCE. HOWEVER... 
A VIGOROUS SHORTWAVE TROUGH CURRENTLY DIGGING INTO THE WESTERN 
ATLANTIC HAS INTRODUCED A COLD FRONT IN THE GULF OF MEXICO AND 
NORTHEAST MEXICO...FOLLOWED BY A FRESH SURGE OF HIGH PRESSURE. 
THE CONFIGURATION OF BUILDING HIGH PRESSURE TO THE NORTH AND 
RELATIVE LOW PRESSURE TO THE SOUTH OF THE GULF OF TEHUANTEPEC 
FAVORS A RESURGENCE OF GALE CONDITIONS. A 0046 UTC QUIKSCAT PASS 
SUGGESTED AT LEAST 30 KT OF N TO NE WINDS NEAR THE COAST...AND 
IT IS ASSUMED THAT WINDS TO GALE FORCE ARE LIKELY NOW OCCURRING. 
SEAS OVER THIS AREA HAD ONLY JUST BEGUN TO SUBSIDE YESTERDAY 
MORNING WITH THE DECREASE IN WIND...BUT THE REVIVAL OF GALE 
CONDITIONS IS LIKELY KEEPING PEAK WAVE HEIGHTS OF AT LEAST 9 TO 
10 FT WITHIN ABOUT 240 NM SOUTH OF THE GULF OF TEHUANTEPEC. 

AS THE SHORTWAVE TROUGH OVER THE EASTERN CONUS AND WESTERN 
ATLANTIC EXITS EAST...TRANSIENT SHORTWAVE RIDGING IN THE 
SOUTHERN STREAM SHOULD CAUSE THE FRONT OVER THE GULF OF MEXICO 
TO BEGIN LIFTING NORTH AS A WARM FRONT BY FRI. THIS CHANGEABLE 
WEATHER PATTERN WILL LEAD TO A DEMISE OF THE CURRENT GAP WIND 
EVENT IN THE GULF OF TEHUANTEPEC...WITH WINDS FORECAST TO DROP 
BELOW GALE FORCE BY THIS EVENING. WINDS SHOULD DIMINISH EVEN 
MORE RAPIDLY FRI...AND NO SIGN OF STRONG WINDS WILL BE EVIDENT 
BY FRI AFTERNOON OR EVENING. WELL-DEVELOPED SEAS OF UP TO 9 TO 
10 FT SHOULD BEGIN SUBSIDING EARLY FRI...WITH A MORE RAPID DROP 
OFF LIKELY LATER IN THE DAY.

ELSEWHERE...GAP WINDS NEAR AND DOWNWIND OF THE GULF OF PAPAGAYO 
HAVE BEEN ACTIVE FOR WELL MORE THAN A WEEK NOW...AND THERE ARE 
NO SIGNS OF AN END TO THE CURRENT EVENT ANY TIME SOON. IN FACT...
THE CURRENT PATTERN OF LOW-LEVEL RIDGING ARCING FROM NORTHEAST 
MEXICO INTO CENTRAL AMERICA FAVORS A CONTINUATION OF GULF OF 
PAPAGAYO WINDS IN THE SHORT-TERM. QUIKSCAT AND ASCAT PASSES 
DURING THE LAST 6 TO 12 HOURS SUGGESTED NE TO E WINDS OF 20 TO 
25 KT...THOUGH THESE WINDS WERE IN A VERY NARROW AREA ABOUT 45 
NM EITHER SIDE OF A LINE FROM 10.5N85.5W TO 10.5N88W. SEAS ARE 
ESTIMATED TO BE UP TO 8 OR 9 FT. STRONG SURFACE RIDGING 
EXTENDING FROM THE EASTERN CONUS INTO THE WESTERN HALF OF THE 
CARIBBEAN AND CENTRAL AMERICA THE NEXT FEW DAYS SHOULD MAINTAIN 
GAP WINDS THROUGH THE GULF OF PAPAGAYO THROUGH AT LEAST 48 HOURS.

FINALLY...ENHANCED LOW-LEVEL SUBTROPICAL RIDGING NORTH OF THE 
AREA NEAR 34N134W SHOULD SHIFT SLOWLY WEST DURING THE NEXT DAY 
OR TWO...AS A COLD FRONT DESCENDS TO NEAR THE NORTHERN BORDER BY 
EARLY SAT. THE STRONG PRESSURE GRADIENT SOUTH OF THE RIDGE HAS 
BEEN MAINTAINING NE TO E 20 TO 25 KT WINDS ROUGHLY FROM 11N TO 
22N W OF 130W THE LAST FEW DAYS...WITH SPOTTIER NE TO E 20 KT 
WINDS OVER AN EVEN LARGER EXPANSE FROM 10N TO 25N W OF 115W. 
WAVE HEIGHTS ARE ESTIMATED TO BE 8 TO 12 FT IN A MIXTURE OF NW 
SWELL AND NE WIND WAVES OVER THE WESTERN PART OF THIS AREA. 
LITTLE CHANGE TO THIS PATTERN IS INDICATED THE NEXT FEW 
DAYS...EXCEPT FOR THE ARRIVAL OF MORE RECENTLY-GENERATED NW 
SWELL OVER THE NORTHERN WATERS AND LONG PERIOD SW SWELL ARRIVING 
AND LATER COVERING THE AREA S OF 10N W OF 110W.

$$
KIMBERLAIN