000
AXPZ20 KNHC 010411
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT DEC 01 2007

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 
0315 UTC.
 
...ITCZ...
ITCZ AXIS IS ALONG 8N77W 5N90W 10N120W 8N140W. SCATTERED 
MODERATE IS FROM 8N-10N BETWEEN 130W AND 138W. 

...DISCUSSION...
A SHORTWAVE RIDGE HAS ITS MEAN AXIS ALONG THE WESTERN BOUNDARY 
OF THE DISCUSSION AREA...ROUGHLY 142W...WITH THE UPPER FLOW 
ANTICYCLONIC FROM THE NW DIVING INTO A DEEP LAYER TROUGH WITH 
ITS MEAN AXIS N OF 10N ALONG 128W AT THE MOMENT. A SECOND UPPER
TROUGH...OR DRY SURGE...IS MOVING INTO THE PATTERN AND IS 
CURRENTLY ALONG 35N124W 33N130W. A SURFACE LOW IS NEAR 25N123W 
1011 MB WITH TOWERING CUMULUS OBSERVED NEAR THE CENTER. A BAND 
OF UPPER MOISTURE IS NOTED WITHIN 90 NM EITHER SIDE OF LINE 
35N120W 31N127W 35N140W AND EXTENDS S OVER THE W SEMICIRCLE OF 
THE SURFACE LOW MERGING WITH THE DEBRIS FROM THE CONVECTION 
DIRECTLY ASSOCIATED WITH THE SURFACE LOW. OTHERWISE...THE UPPER 
LEVELS ARE VERY DRY N OF 12N W OF 120W. THE SURFACE LOW IS 
EXPECTED RESPOND TO THE APPROACHING SECOND UPPER TROUGH AND 
RAPIDLY LIFT NE OF THE AREA TONIGHT. 

A TROPICAL UPPER CYCLONE IS NEAR 3N103W WITH ITS ENVELOP OF 
CYCLONIC FLOW NOTED WITHIN 420 NM OF THE CENTER. IMMEDIATELY TO 
THE N...AN UPPER ANTICYCLONE IS NEAR 14N106W WITH AN UPPER RIDGE 
EXTENDING NW TO A CREST ALONG 32N119W 35N117W. SOME OF THE 
DEBRIS MOISTURE FROM ITCZ CONVECTION BETWEEN 125W AND 140W IS 
ADVECTED SE BUT SEEMS TO EVAPORATE BEFORE REACHING THE EQUATOR. 
SOME OF THE DEBRIS MOISTURE IS ADVECTED NE BETWEEN THE UPPER 
TROUGH AND ALONG THE W PERIPHERY OF THE UPPER RIDGE. THIS 
MOISTURE MERGES WITH ADDITIONAL DEBRIS MOISTURE FROM SCATTERED 
MODERATE ISOLATED STRONG CONVECTION...NOTED WITHIN 60 NM EITHER 
SIDE OF LINE 23N113W 14N117W. THE RESULT IS A TROPICAL PLUME 
WITHIN 470 NM EITHER SIDE LINE 12N115W 23N112W TO BEYOND 
32N108W.      

GAP WINDS...EXPECT DRAINAGE WINDS AT 20 TO 25 KT FROM JUST AFTER 
SUNRISE TIL ABOUT MID MORNING ON SAT IN BOTH THE GULF OF 
TEHUANTEPEC AND GULF OF PAPAGAYO AREAS. EXPECT WINDS TO DIMINISH 
IN BOTH AREAS BY SUNSET SAT.

NEXT CONCERN IS SOUTHERLY FLOW BEGINS EXTREME NW PORTION LATE 
SAT AND INCREASES TO 35 KT GALE CONDITIONS IN 48 HOURS.

$$
FORMOSA