000
AXPZ20 KNHC 041522
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE DEC 04 2007

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN
FROM THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1500 UTC.
 
...ITCZ...
INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...6N77W 6N100W 
7N120W 6N140W. SCATTERED MODERATE CONVECTION IS WITHIN 60 NM OF 
THE POINTS 6N90W AND 7N109.5W. SCATTERED MODERATE TO STRONG 
CONVECTION IS WITHIN THE AREA 90 NM EITHER SIDE OF THE ITCZ AXIS 
FROM 111W TO 119W.

...DISCUSSION...
UPPER LEVELS...
BROAD DEEP LAYER TROUGH COVERS THE CENTRAL PACIFIC WELL NW OF 
THE AREA. A NARROW MID TO UPPER LEVEL RIDGE AXIS WAS E OF THE 
BROAD TROUGH WITH AXIS ALONG 32N131W SWWD TO NEAR 22N140W. 
FURTHER E...AN UPPER LEVEL ANTICYCLONE WAS NEAR 20N119W AND 
DOMINATED THE FLOW OVER THE AREA FROM 15N TO 25N BETWEEN 100W 
AND 128W. A NARROW UPPER LEVEL TROUGH AXIS WAS NOTED BETWEEN THE 
TWO AREAS OF ANTICYCLONIC FLOW WITH AN AXIS ALONG 32N127W SSWWD 
TO AN UPPER LEVEL CYCLONIC CIRCULATION NEAR 14N137W THEN 
CONTINUING SE TO NEAR TO 9N131W. 

ANOTHER UPPER LOW IS IN THE DEEP TROPICS NEAR 6N118W WITH UPPER 
TROUGH AXIS EXTENDING NWD TO 15N123W. A NARROW CHANNEL OF SE 
UPPER LEVEL FLOW IS NOTED BETWEEN THIS UPPER TROUGH...THE UPPER 
CYCLONIC CIRCULATION/LOW TO THE W AND ANTICYCLONE TO THE N 
DRAWING TROPICAL MOISTURE NWWD TO 25N BETWEEN 123W AND 133W.

FURTHER N...AN UPPER LEVEL SHEAR/TROUGH AXIS FROM SE TEXAS 
ACROSS NORTH CENTRAL MEXICO THEN ALONG THE WEST COAST OF 
MAINLAND MEXICO THEN ACROSS THE GULF OF CALIFORNIA AND CENTRAL 
BAJA CALIFORNIA. STRONG SUBSIDENCE IN ITS WAKE WAS SWEEPING SWD 
AT 15 KT AND WAS IMPINGING UPON THE ANTICYCLONE NEAR 20N119W.   
AN UPPER LEVEL CYCLONIC CIRCULATION WAS NOTED NEAR 30.5N118.5W 
WITH DRY AIR WITHIN 200 NM OF THE CENTER.

AT THE SURFACE...A STATIONARY FRONT OVER THE EXTREME NW PART OF 
THE AREA WAS BECOMING INCREASINGLY ILL-DEFINED WITH ONLY MODEST 
SHOWER ACTIVITY WITHIN 60-90 NM E OF THE FRONT. RIDGE COVERS THE 
REMAINDER OF THE AREA N OF THE ITCZ W OF 113W. BROAD TROUGH IS 
ANALYZED ELSEWHERE.

GAP WINDS OF 20 TO 25 KT IN THE GULF OF TEHUANTEPEC AREA. THESE 
WINDS ARE FORECAST WINDS TO DROP TO LESS THAN 20 KT IN 24 HOURS.
ALSO IN THE GULF OF PAPAGAYO AREA EAST WINDS OF NEAR 20 KT ARE 
EXPECTED OVER THE NEXT 12 HOURS. 

NW TO N WINDS OF 20 KT OVER THE N PORTION OF THE GULF OF 
CALIFORNIA. THESE WINDS ARE EXPECTED TO SUBSIDE TO LESS THAN 20 
KT WITHIN 18 HOURS. 

LARGE NORTHWEST SWELLS OF UP TO 25 FT OBSERVED OVER THE 
NORTHWEST PART OF THE AREA WILL SPREAD SOUTHEAST THROUGH 48 
HOURS AND IMPACT MOST OF THE AREA NORTH OF THE EQUATOR
AND WEST OF 115W. 

$$
LL