000
AXPZ20 KNHC 081511
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU JAN 08 2009

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...06N78W TO 
06N96W TO 07N106W TO 09N118W TO 08N131W TO 07N140W. SCATTERED 
MODERATE CONVECTION IS WITHIN 30 NM OF THE POINTS 05N78W AND 
09N125W. SCATTERED MODERATE IS WITHIN 30 NM EITHER SIDE OF ITCZ 
AXIS BETWEEN 129W AND 136W.

OTHER CONVECTION NEAR THE ITCZ...SCATTERED MODERATE CONVECTION 
IS FROM 10N TO 12N BETWEEN 121W AND 125W.

...DISCUSSION...

TRADES...
AN AMPLIFIED AND PROGRESSIVE UPPER PATTERN IS FORECAST TO 
CONTINUE FOR THE REMAINDER OF THIS WEEK. A PAIR OF UPPER RIDGES 
AND AN UPPER TROUGH WILL TRANSLATE EASTWARD OVER THE CENTRAL AND 
EASTERN PACIFIC THROUGH THIS WEEKEND. AT THE SURFACE...A 1031 MB 
SURFACE HIGH IS CENTERED IN THE CENTRAL PACIFIC NEAR 39N142W. NE 
TRADE WINDS OF 20 KT...OCCASIONALLY TO 25 KT...ARE AFFECTING 
AREAS S OF THE SURFACE HIGH. HOWEVER...WITH THIS HIGH WELL NORTH 
OF THE AREA AND WITH THE APPROACH OF A REMNANT COLD FRONT FROM 
THE N... THESE TRADE WINDS WILL CONTINUE TO SLOWLY DECREASE IN 
AREAL COVERAGE AND INTENSITY. THE TRADE WINDS CONTINUE TO RESULT 
IN SEA HEIGHTS OF 8 TO 11 FT...WHICH WILL CONTINUE TO SUBSIDE 
THROUGH LATE WEEK. ADDITIONALLY...A MID/UPPER-LEVEL LOW IS 
CENTERED NEAR 23N125W. HOWEVER...SUBSIDENCE ASSOCIATED WITH THE 
SURFACE HIGH IS CURRENTLY INHIBITING THE DEVELOPMENT OF A 
SURFACE TROUGH ASSOCIATED WITH THE LOW. HOWEVER...IT IS POSSIBLE 
THAT THE PHASING OF THE LOW WITH THE AFOREMENTIONED UPPER TROUGH 
COULD RESULT IN THE OCCASIONAL DEVELOPMENT OF A SURFACE TROUGH 
DURING THE NEXT FEW DAYS. THIS COULD CAUSE TEMPORARY 
ENHANCEMENTS TO THE TRADE WINDS ACROSS THE NORTHERN PERIPHERY OF 
ANY SURFACE TROUGHS THAT DEVELOP.

GULF OF PAPAGAYO...
THE INCREASING CARIBBEAN TRADES ARE RESULTING IN 20 KT WINDS 
FUNNELING INTO THE GULF OF PAPAGAYO. DURING THE NEXT COUPLE OF 
DAYS...THESE WINDS WILL INCREASE IN AREAL COVERAGE AND INTENSITY 
AS THE CARIBBEAN TRADES STRENGTHEN...AND AS A BROAD SURFACE 
TROUGH DEVELOPS SW OF COSTA RICA. ALSO...THESE WINDS WILL BE 
ENHANCED BY DOWNSLOPE FLOW AT NIGHT OVER THE HIGHER TERRAIN OF 
COSTA RICA.

GULF OF CALIFORNIA...
A HIGHLY AMPLIFIED UPPER RIDGE IS FORECAST TO BUILD OVER THE E 
PACIFIC AND W CONUS THIS WEEKEND...WITH A STRONG SURFACE RIDGE 
EXTENDING FROM THE GREAT BASIN TO THE NORTHERN ROCKIES. IN 
FACT...NUMERICAL MODEL GUIDANCE SUGGESTS THAT A 1045 MB SURFACE 
HIGH COULD SET UP OVER SE IDAHO BY SATURDAY. THIS PATTERN WILL 
BE PARTICULARLY FAVORABLE FOR THE DEVELOPMENT OF STRONG 
NORTHWESTERLY GALES THROUGH THE GULF OF CALIFORNIA THIS WEEKEND.

GULF OF TEHUANTEPEC...
A STRONG COLD FRONT WILL SURGE SOUTHWARD ACROSS THE WESTERN GULF 
THIS WEEKEND...FOLLOWED BY A 1032 MB SURFACE HIGH OVER SE TEXAS. 
THIS WILL QUICKLY INCREASE THE PRESSURE GRADIENT BETWEEN THE BAY 
OF CAMPECHE AND THE GULF OF TEHUANTEPEC. CORRESPONDINGLY... 
STRONG WINDS WILL FUNNEL THROUGH THE ISTHMUS OF TEHUANTEPEC... 
RESULTING IN STRONG GALE FORCE WINDS...POSSIBLY STORM FORCE 
WINDS...ACROSS THE GULF OF TEHUANTEPEC LATE THIS WEEKEND AND 
EARLY NEXT WEEK.

$$
COHEN/CANGIALOSI