000
AXPZ20 KNHC 130322
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC TUE JAN 13 2009

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 
0230 UTC.

...ITCZ...
ITCZ IS ALONG 6N76W 5N91W 9N112W 5N140W. NUMEROUS MODERATE TO 
SCATTERED STRONG CONVECTION FROM 05N TO 13N BETWEEN 96W AND 
110W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION FROM 08N 
TO 13N BETWEEN 110W TO 119W.

...DISCUSSION...
NARROW UPPER LEVEL TROUGH BETWEEN TWO UPPER RIDGES EXTENDS INTO 
THE FAR NW PORTION OF THE DISCUSSION AREA THROUGH 32N135W TO 
25N126W. THE UPPER RIDGE TO THE S OF THE TROUGH COVERS THE AREA 
W OF 128W. VERY BROAD UPPER HIGH IS TO THE NE OF THE UPPER 
TROUGH ANCHORED NEAR 39N128W COVERING THE AREA N OF 26N W OF 
110W. MODERATE TO STRONG SUBSIDENCE WITH DRY STABLE AIR COVERS 
THE AREA N OF 23N TO OVER BAJA PENINSULA AND NW MEXICO. AN UPPER 
LEVEL TROUGH OVER THE CENTRAL U.S. IS E OF THE BROAD UPPER HIGH 
AND EXTENDS S TO OVER N MEXICO. SLY UPPER FLOW S OF MEXICO E OF 
110W COMBINED WITH THE DIFFLUENCE ALOFT S OF THIS UPPER TROUGH 
IS SUPPORTING CONVECTION ASSOCIATED WITH THE ITCZ. 

A SURFACE RIDGE DOMINATES MUCH OF THE AREA N OF 20N BETWEEN 120W 
AND 145W ANCHORED BY A 1037 MB HIGH OFF THE NW U.S. COAST. A 
SURFACE RIDGE EXTENDS OVER N MEXICO AND IS MAINTAINING A STRONG 
PRES GRADIENT ACROSS SOUTHERN MEXICO AND WITH THE PASSAGE OF 
FRONT IN THE GULF OF MEXICO IS PRODUCING GALE FORCE WINDS 
CONTINUING THROUGH THE GULF OF TEHAUNTEPEC. 

$$
WALLACE