000
AXPZ20 KNHC 020936
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SUN JAN 02 2011

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 
0900 UTC.

...ITCZ...
AXIS IS ALONG 5N77W 8N115W 7N130W 7N140W. SCATTERED MODERATE 
ISOLATED STRONG CONVECTION WITHIN 60 NM N OF AXIS FROM 137W-140W.

...DISCUSSION...
BROAD UPPER LEVEL RIDGE OVER THE NW PORTION OF THE DISCUSSION 
AREA N OF 20N W OF 130W. DOWNSTREAM UPPER LEVEL TROUGH EXTENDS 
FROM AN UPPER LEVEL CYCLONIC CIRCULATION OFF THEN NORTHERN 
CALIFORNIA COAST TO 32N119W THEN SW TO 25N128W. A 90-115 JET 
STREAM SE OF THE TROUGH FROM 27N123W TO ACROSS NORTHERN MEXICO. 
BROKEN CIRRUS CLOUDS ARE WITHIN 300 NM S OF THE JET. IN THE DEEP 
TROPICS AN UPPER LEVEL TROUGH EXTENDS FROM 16N112W TO THE 
EQUATOR AT 113W. SW FLOW E OF THE TROUGH AXIS IS ADVECTING UPPER 
LEVEL MOISTURE INTO CENTRAL MEXICO. AN UPPER LEVEL RIDGE IS S OF 
15N W OF 125W...EXCEPT FOR SOME SCATTERED CONVECTIVE ACTIVITY 
ALONG THE ITCZ...MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE 
AIR AT THE MIDDLE AND UPPER LEVELS IS S OF 20N W OF 125W.

A WEAK COLD FRONT IS MOVING INTO THE FAR N PORTION OF THE AREA 
FROM 32N129N TO 30N135W THEN TO 31N138W. LITTLE WEATHER IS 
ASSOCIATED WITH THE FRONT. AS THE FRONT MOVES EWD IT WILL 
STRENGTHEN AND LARGE NW SWELLS WILL PROPAGATE SWD. A 1025 MB 
HIGH PRES IS ANALYZED NEAR 29N121W. ELY WINDS ALONG THE SOUTHERN 
PERIPHERY OF THE HIGH UP TO 20 KT FROM 11N-23N BETWEEN 
115W-130W.  

HIGH PRES BUILDING SWD ACROSS MEXICO WILL TIGHTEN THE PRES 
GRADIENT PRODUCING NLY TO 20-25 KT LATER TODAY IN THE GULF OF 
TEHUANTEPEC THEN INCREASE TO 30 KT TONIGHT. THE GRADIENT WEAKENS 
AND WINDS DECREASE MON NIGHT.

$$
DGS