000
AXPZ20 KNHC 020334
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI JAN 02 2009

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE WAS ALONG THE LINE...04N77W 
TO 03N83W TO 05N93W TO 09N108W TO 11N123W TO 08N130W TO 08N140W. 
NUMEROUS MODERATE WITH SCATTERED STRONG CONVECTION WAS OCCURRING 
FROM 09N TO 15N AND BETWEEN 117W AND 107W. NUMEROUS MODERATE 
WITH ISOLATED STRONG CONVECTION WAS OCCURRING WITHIN 120 NM N OF 
AXIS...BETWEEN 130W AND 120W.

...DISCUSSION...

AN UPPER LOW HAS BECOME CUT OFF FROM THE MEAN FLOW TO THE SW OF 
THE HAWAIIAN ISLANDS...WHILE A TUTT AXIS HAS BECOME ESTABLISHED 
DURING THE PAST 24 HOURS FROM THE SW U.S. WEST SOUTHWESTWARD TO 
28N143W. ZONAL FLOW ALOFT CAN BE FOUND WITHIN 5 TO 10 DEGREES N 
OF THE TUTT AXIS...AND ALSO S OF THIS AXIS BETWEEN 15N AND 25N 
EXTENDING EASTWARD ACROSS MEXICO. TWO SHORT WAVE TROUGHS 
EMBEDDED WITHIN THIS WESTERLY UPPER FLOW ACROSS THE TROPICS ARE 
SLIGHTLY NEGATIVELY TILTED...AND ARE VENTING ZONES OF ACTIVE 
CONVECTION MENTIONED ABOVE...AND ASSOCIATED WITH LOW LEVEL WAVES 
IN THE EASTERLIES. VERY DRY AND STABLE CONDITIONS PREVAIL ACROSS 
THE EXTREME EASTERN TROPICAL PACIFIC TONIGHT...E OF 105W...WHERE 
MILD AND RELATIVELY DRY AIR CONTINUES TO MOVE FROM THE CARIBBEAN 
AND ACROSS CENTRAL AMERICA.  

DESCENDING PASSES OF QUIKSCAT DATA HAVE JUST BECOME AVAILABLE 
THIS EVENING FOR THE ATLANTIC AND CARIBBEAN...AND WILL COVER THE 
EASTERN PACIFIC IN THE NEXT 6 TO 8 HOURS...AND RETURN CONFIDENCE 
AND SPECIFICITY TO THE FORECASTS. GALE CONDITIONS ACROSS THE 
GULF OF TEHUANTEPEC REGION ENDED THIS AFTERNOON.

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....JUST 
MILD FLUCTUATIONS IN INTENSITY AND AREAL EXTENT. THE CURRENT 
PATTERN OF LOW-LEVEL RIDGING ARCING FROM NORTHEAST MEXICO INTO 
CENTRAL AMERICA FAVORS A CONTINUATION OF GULF OF PAPAGAYO WINDS 
THROUGH 48 HOURS...WITH RECENT GUIDANCE SUGGESTING A POSSIBLE 
STRENGTHENING OF THE FLOW THERE AFTER 48 HOURS. NORTHERLY WINDS 
OF 20 KT ARE EXPECTED TO CONTINUE ACROSS THE GULF OF PANAMA AND 
DOWNWIND TO 06N...BEFORE SUBSIDING BY 24 HOURS...AND POTENTIAL 
RESURGENCE AFTER 48 HOURS.  

ENHANCED LOW-LEVEL SUBTROPICAL RIDGING NORTH OF THE AREA...WITH 
A 1030 MB SURFACE HIGH CENTERED NEAR 33N134W...SHOULD SHIFT 
SLOWLY WEST DURING THE NEXT DAY OR TWO...AS A COLD FRONT 
DESCENDS TO NEAR 30N OVERNIGHT FRI/EARLY SAT. THE STRONG 
PRESSURE GRADIENT SOUTH OF THIS RIDGE HAS BEEN MAINTAINING NE TO 
E 20 TO 25 KT WINDS ROUGHLY FROM 10N TO 22N W OF 128W THE LAST 
SEVERAL 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 9 TO 11 FT IN A MIXTURE OF NW SWELL AND NE WIND 
WAVES OVER THE WESTERN PORTIONS OF THIS AREA. ONLY MODEST 
CHANGES TO THIS PATTERN ARE INDICATED DURING THE NEXT FEW 
DAYS...EXCEPT FOR THE ARRIVAL OF MORE RECENTLY GENERATED NW 
SWELL OVER THE NORTHERN WATERS...AND LONG PERIOD SW SWELL 
ARRIVING FROM THE SOUTHERN HEMISPHERE...WITH PEAK ENERGY 
FOCUSED AT CENTRAL AMERICA AND NW SOUTH AMERICA. 

FINALLY...ISOLATED TO SCATTERED TRADE WIND SHOWERS OF LIGHT TO 
MODERATE INTENSITY WILL CONTINUE DURING THE NEXT 12 HOURS ACROSS 
CENTRAL AMERICA FROM THE YUCATAN TO COSTA RICA...MAINLY ALONG 
THE CARIBBEAN COASTS AND EASTERN SLOPES OF THE MOUNTAINS.

$$
STRIPLING