000
AXPZ20 KNHC 102201
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2305 UTC MON DEC 10 2007

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE AXIS IS ALONG 7N78W 9N106W 5N123W 
7N140W. SCATTERED MODERATE ISOLATED STRONG WITHIN 15 NM EITHER 
SIDE OF LINE 7N77W 6N84W AND WITHIN 120 NM EITHER SIDE OF LINE 
8N100W 12N106W.

...DISCUSSION...
AN UPPER LONGWAVE TROUGH LIES ALONG THE W COAST N AMERICA WITH 
ITS AXIS ALONG 115W INTO THE E PAC TO A BASE NEAR 10N122W. AN 
EMBEDDED DEEP LAYERED CYCLONE IS AT 30N114W AND APPEARS TO BE 
SHIFTING E WITH TIME. A BAND OF DRY UPPER AIR IS ROTATING 
THROUGH THE UPPER TROUGH WITHIN 120 NM EITHER SIDE OF POINTS 
25N110W 18N120W 27N130W. AT THE SURFACE LOW PRES IS ANALYZED AT 
32N111W 1007 MB AND A SECOND LOW PRES AT 29N115W 1011 MB. SOME 
UPPER MOISTURE CONTINUES TO WRAP AROUND THE W PERIPHERY OF THE 
UPPER CYCLONE WITHIN ABOUT 120 NM OF CENTER. ANOTHER BAND OF 
MOISTURE LIES WITHIN 90 NM EITHER SIDE OF LINE 23N119W 32N124W.  

A LOW LEVEL TROUGH IS ANALYZED FROM 14N102W TO 7N108W. 
CONVECTION FLARED EARLIER WITH THE RESULTANT DEBRIS MOISTURE 
MERGING WITH A TROPICAL PLUME NOTED ROUGHLY WITHIN 270 NM EITHER 
SIDE OF LINE 9N117W TO BEYOND 32N101W.

JUST TO THE W OF THE UPPER LONGWAVE TROUGH...AN UPPER SHORTWAVE 
RIDGE LIES ALONG 136W AND ORIGINATES FROM AN UPPER ANTICYCLONE 
NEAR 4S138W. SOME UPPER MOISTURE IS SPILLING ACROSS THE RIDGE 
OVER THE DISCUSSION AREA FROM 9N TO 24N W OF 132W. 

THE E PORTION OF THE DISCUSSION AREA IS DOMINATED BY A SHORTWAVE 
RIDGE THAT EXTENDS ACROSS CENTRAL AMERICA AND THE WESTERN GULF 
OF MEXICO. AN UPPER ANTICYCLONE APPEARS TO BE FORMING ALONG THE 
RIDGE NEAR 13N82W. THIS MAY BE IN RESPONSE TO AN ATLC UPPER 
TROUGH EXTENDING SW INTO THE W CARIBBEAN THAT MAY EFFECTIVELY 
SPLIT THE UPPER RIDGE INTO TWO COMPONENTS. 

SOME DEBRIS MOISTURE FROM ITCZ CONVECTION ALONG 6N E OF 84W AND 
DEBRIS FROM TOWERING CUMULUS OVER COSTA RICA AND NICARAGUA IS 
ALL TRAPPED UNDER THE RIDGE. OTHERWISE THE UPPER LEVELS ARE DRY 
SE OF LINE 28N92W 6N90W.    

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS INTO THE AREA LONG 
32N137W 22N113W.

GAP WINDS...STRONG CARIBBEAN WINDS EXPECTED TO SURGE THROUGH THE 
GULF OF PAPAGAYO THROUGH NEXT 48 HRS. N WINDS SURGED INTO THE 
GULF OF TEHUANTEPEC AT ABOUT 20 KT EARLIER TODAY. EXPECT N 
DRAINAGE SURGES IN THE 15 KT RANGE JUST AFTER SUNRISE FOR THE 
NEXT FEW DAYS.  

$$
NELSON