000
AXPZ20 KNHC 040954
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC WED DEC 04 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
MONSOON TROUGH FROM 08N78W TO 10N88W TO 08N96W TO 08N116W TO 
06N124W THEN ITCZ TO 10N134W TO BEYOND 09N140W.  SCATTERED
MODERATE ISOLATED STRONG CONVECTION WITHIN 60 NM OF AXIS
FROM 114W TO 118W.

...DISCUSSION...
WEAKENING DEEP LAYER CYCLONE AT 25N128W HAS MID TO UPPER LEVEL
TROUGH EXTEND S TO 10N128W. VERY DRY STABLE AIR MASS W OF TROUGH
BUT MOISTURE ENCROACHING INTO NW CORNER OF BASIN ON TOP OF RIDGE
CREST NOW ALONG 140W.  DOWNSTREAM OF TROUGH...100 KT JETSTREAM
ADVECTS ABUNDANT MOISTURE OVER BAJA CALIFORNIA...NORTHERN MEXICO
AND TEXAS FEEDING DEVELOPING LOW PRES CENTER OVER SOUTHERN
CALIFORNIA AND ITS ASSOCIATED FRONTAL BOUNDARY. 

LARGE MID TO UPPER LEVEL ANTICYCLONE OVER MEXICO AT 18N93W 
CONTRIBUTES CONVECTIVE DEBRIS MOISTURE FROM WEAK SURFACE TROUGH
ALONG 115W TO ABOVE SCENARIO.  OTHERWISE...RIDGE CAPS VERY DRY
AIR MASS OVER BASIN S OF 20N E OF 110W.

...ELSEWHERE AT THE LOWER LEVELS...
SURFACE LOW PRES 1012 MB AT 21N133W TIGHTENS PRES GRADIENT WITH
HIGH PRES N OF AREA BRINGING FRESH NE TRADES N OF 23N W OF 133W.  
LOW PRES EXPECTED TO DISSIPATE AS CYCLONE ALOFT OPEN INTO TROUGH
AND SHIFTS NE DIMINISHING TRADES TO A MODERATE NE BREEZE.  BUT
THIS ALLOWS VIGOROUS HIGH PRES TO MOVE OVER NORTHERN PART OF BASIN
BRINGING STRONG NE-E WINDS BACK AGAIN N OF 20N W OF 125W. 

WEAK TROUGH EMBEDDED IN MONSOON TROUGH HAS FRESH E-SE BREEZE AND
8-9 FT SEAS ASSOCIATED WITH IT.  TROUGH EXPECTED TO DISSIPATE BY
THU WITH MARINE CONDITIONS IMPROVING IMMEDIATELY.

$$
WALLY BARNES