000
AXPZ20 KNHC 042203
TWDEP 

TROPICAL WEATHER DISCUSSION     
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU JAN 4 2007

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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...ITCZ...
AXIS IS CENTERED ALONG 5N77W 5N90W 6N100W 6N110W 6.5N120W
6N130W 6N140W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION 
IS WITHIN 45 NM EITHER SIDE OF THE AXIS BETWEEN 121W-125W.

...DISCUSSION....

STRONG 1045 MB HIGH PRES LOCATED NEAR 38N148W CONTINUES TO SHIFT 
E TOWARD THE CALIFORNIA COAST IS PUSHING A COLD FRONT TO THE NW 
CORNER OF THE DISCUSSION AREA. AS THE SURFACE HIGH SLIDES 
FURTHER E...THE PRES GRADIENT WILL TIGHTEN CONSIDERABLY FROM THE 
CALIFORNIA COAST SWWD THROUGH THE DISCUSSION AREA WITH GALE 
CONDITIONS EXPECTED TO DEVELOP IN THE NORTHERN TRADES BY LATE 
THU NIGHT...NW OF A LINE FROM 30N118W TO ABOUT 20N140W. THIS 
AREA OF GALE FORCE WINDS IS THEN EXPECTED TO SHIFT SWD THROUGH 
THE NEXT 48 HRS. GALE FORCE CONDITIONS...IN THE RANGE OF 25-35 
NW WINDS ARE ALSO EXPECTED TO BEGIN TO IMPACT THE NRN PORTION OF 
THE GULF OF CALIFORNIA IN ABOUT 36 HRS AND LAST FOR ABOUT 48 HRS 
ONCE THE COLD FRONT HAS MOVED INLAND ACROSS THE DESERT SW AND 
HIGH PRES OVER THE GREAT BASIN INTERACTS WITH LOWER PRESSURE 
ALONG THE PACIFIC COAST OF MEXICO.

A MID TO UPPER LEVEL TROUGH EXTENDS FROM CENTRAL TEXAS SW THROUGH
NORTHERN MEXICO...AND CONTINUES SW TO SOUTHERN BAJA CALIFORNIA.
UPPER LEVEL CONVERGENCE NEAR THE TROUGH AXIS CONTINUES TO RESULT
IN STRONG SUBSIDENCE FROM 18N-30N E OF 120W. A SUBTROPICAL JET
STREAM BRANCH EXTENDS FROM 16N122W ENE THROUGH 17N115W THEN
TURNS MORE NE THROUGH 18N108W AND ACROSS CENTRAL MEXICO. THE
JET STREAM IS ADVECTING EXTENSIVE UPPER LEVEL PACIFIC MOISTURE 
FROM THE ITCZ. THIS MOISTURE EXTENDS WITHIN 360-500 NM SE OF THE 
JET STREAM...AND IS BEING CHANNELED ACROSS CENTRAL MEXICO AND
NE WELL ACROSS THE WESTERN AND NORTHERN PORTIONS OF THE GULF OF 
MEXICO.

A MID/UPPER LEVEL CYCLONIC CIRCULATION MOVING WESTWARD ABOUT 
15-20 KT IS CENTERED NEAR 13N129W WITH A TROUGH EXTENDING SW 
TO 8N132W. DIFFLUENT FLOW PATTERN OCCURRING WITHIN 480 NM SE OF 
THIS CIRCULATION IS ENHANCING ITCZ CONVECTION BETWEEN 121W-125W. 
A MID/UPPER LEVEL NEARLY STATIONARY ANTICYCLONIC CIRCULATION IS 
LOCATED NEAR 25N122W. OVER THE EASTERN PORTION OF THE REGION...
MID/UPPER LEVEL RIDGING EXTENDS ALONG 11N E OF 101W. MODERATE
TO STRONG SUBSIDENCE AND ASSOCIATED DRY AIR COVERS THE REMAINDER
OF THE REGION. FRESH TO STRONG WINDS WILL CONTINUE OVER THE GULF 
OF PAPAGAYO THROUGH THE NEXT 24 HRS...THEN DIMINISH TO 15-20 KT
IN 48 HRS OR SHORTLY AFTERWARDS AS GRADIENT OVER THE CARIBBEAN 
WEAKENS.

$$
AGUIRRE