000
AXPZ20 KNHC 040952
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED FEB 04 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 
0945 UTC.

...ITCZ...

ITCZ AXIS EXTENDS FROM S AMERICA AT 02N78W TO S OF THE EQUATOR 
AT 01S94W THEN W NW ACROSS THE EQUATOR AT 100W TO 03N140W. 
ISOLATED MODERATE AND STRONG CONVECTION IS OBSERVED WITHIN 60 NM 
OF 06.5N77.5W AND ALSO WITHIN 120 NM OF 06N82W. OTHERWISE... 
LOCALLY OVERCAST LOW CLOUDS WITH EMBEDDED WEAK SHOWERS WERE 
NOTED FROM 07N TO THE EQUATOR E OF 116W. 

...DISCUSSION...

A QUASI STATIONARY UPPER ANTICYCLONE IS CENTERED OVER THE DEEP 
TROPICS NEAR 10N104W WITH ITS ASSOCIATED RIDGE SHIFTED S...AND 
NOW CRESTING ALONG 10N110W TO 17N100W TO 15N85W. UPPER DEBRIS 
MOISTURE...FROM CONVECTION THAT FLARED EARLIER TO THE S OF 10N E 
OF 85W...AND THE LINGERING CONVECTION DESCRIBED ABOVE...IS NOTED 
SE OF LINE FROM 03N88W TO THE SW CARIBBEAN NEAR 11N87W. THE 
EASTERN CONUS IS DOMINATED BY A LONG WAVE TROUGH THAT HAS DUG S 
TO BASE OVER THE BAY OF CAMPECHE AND IS ACCOMPANIED BY VERY DRY 
UPPER AIR THAT MERGES WITH DRY UPPER AIR ASSOCIATED WITH 
TROPICAL RIDGE...RESULTING IN VERY DRY UPPER AIR OVER THE ENTIRE 
AREA N OF 20N E OF 110W AND S OF 20N E OF 120W.

A NEGATIVE TILT LONG WAVE UPPER TROUGH EXTENDS ACROSS THE AREA 
FROM 32N133W TO THE EQUATOR AT 118W. AN EMBEDDED SHORT WAVE 
TROUGH HAS ITS AXIS TO THE N OF 18N ALONG 137W...WITH BAND OF 
DRY UPPER AIR NOTED WITHIN 120 NM EITHER SIDE OF LINE 27N125W TO 
22N140W. SMALL EMBEDDED UPPER CYCLONES ARE NOTED NEAR 12N120W 
AND 03N119W. AN EMBEDDED SHORTWAVE ANTICYCLONE IS NOTED NEAR 
11N127W WITH A SHORTWAVE RIDGE EXTENDING NE TO NEAR 
26N117W...WITH A BAND OF UPPER MOISTURE NOTED WITHIN 180 NM 
EITHER SIDE OF LINE 16N133W TO 24N117W TO BEYOND 32N120W...AND 
SPREADING NE ACROSS SOUTHERN CALIFORNIA. A TROPICAL RIDGE OVER 
THE CENTRAL PACIFIC EXTENDS E INTO THE AREA TO THE S OF 13N W OF 
130W...AND IS ACCOMPANIED BY DENSE DEBRIS MOISTURE TRAPPED 
WITHIN ITS ENVELOPE OF ANTICYCLONIC UPPER FLOW. 

AT THE LOW LEVELS...WEAK RIDGING CONTINUES OVER THE AREA N OF 
20N E OF 125W. A COLD FRONT EXTENDS FROM 32N134W TO 24N140W 
WHERE IT IS ALREADY LOSING IDENTITY. THE UPPER SUPPORT REMAINS 
N OF THE AREA...BUT WILL DRIVE A SERIES OF COLD FRONTS ACROSS 
THE SUB TROPICS THROUGH FRI...THEN A STRONGER COLD FRONT WILL 
MOVE IN THE N CENTRAL PORTION. LARGE NW SWELLS WILL PROPAGATE SE 
OVER MOST OF THE AREA IN THE WAKE OF THE DECAYING FRONTS.   

CENTRAL AMERICAN GAPS...
GULF OF TEHUANTEPEC...STORM FORCE WINDS TO 55 KT EXPECTED TO 
PERSIST THROUGH MID MORNING FRI WITH GALE CONTINUING TO MID 
MORNING SAT. NE WINDS IN AND DOWNSTREAM OF THE GULF OF PAPAGAYO 
HAVE BEEN SURGING AT 20 KT. EXPECT THESE NE WINDS TO RAPIDLY 
INCREASE TO MINIMAL GALE THIS MORNING...SPREADING OVER THE 
ENTIRE AREA N OF 09N E OF 93W THROUGH LATE SAT. NE WINDS ALSO 
EXPECTED TO INCREASE TO 20 TO 25 KT OVER THE PACIFIC COASTAL 
WATERS OF COSTA RICA BY TONIGHT...WITH THESE CONDITIONS 
SPREADING E TO THE PANAMA WATERS THU. MODEL GUIDANCE SUGGEST 
MINIMAL GALE S OF PANAMA...BUT N WINDS TO 30 KT BY LATE THU.  

$$
NELSON