000
AXPZ20 KNHC 271521
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC THU DEC 27 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...5N77W 7N105W 
8N115W 7N125W 8N140W. SCATTERED MODERATE TO STRONG CONVECTION IS 
WITHIN 90 NM OF THE POINT 12N113.3W. SCATTERED MODERATE 
CONVECTION IS WITHIN 60 NM OF THE POINT 12.4N117W.

...DISCUSSION...
UPPER LEVELS...
MIDDLE AND UPPER LEVEL TROUGH IS NORTH OF A LINE 23N140W 22N110W 
TO BEYOND 25N100W. THE AREA IS DRY AND CLOUD FREE IN THE MIDDLE 
AND UPPER LEVELS. THE TROUGH IS FORECAST TO BE IN PLACE THROUGH 
48 HOURS. A PLUME OF MIDDLE AND UPPER LEVEL MOISTURE WITH THIN 
BROKEN MAINLY UPPER LEVEL CLOUDS EXTENDS WITHIN 500 NM SE OF THE 
TROUGH LINE EAST OF 120W AND IS ADVECTING NORTHEASTWARD OVER 
CENTRAL MEXICO.

ANOTHER MAINLY UPPER LEVEL TROUGH IS SOUTH OF THE ITCZ ACROSS 
MOST OF THE AREA. THIS TROUGH IS FORECAST TO PERSIST THROUGH 48 
HOURS ALSO.  THE AREA IS ALSO DRY AND CLOUD FREE IN THE MIDDLE 
AND UPPER LEVELS.

EXCEPT FOR SOME ITCZ CONVECTION THE AREA EAST OF A LINE 20N96W 
15N105W TO THE ITCZ NEAR 110W IS DRY AND CLOUD FREE IN THE 
MIDDLE AND UPPER LEVELS.

REMAINDER OF UPPER LEVELS IS WEAK ANTICYCLONIC FLOW. HOWEVER A 
SHORTWAVE IS EMBEDDED IN THE REGION ALONG 120W SOUTH OF 17N AND 
THIS FEATURE IS ENHANCING CONVECTION IN THE AREA FROM 11N TO 14N 
FROM 110W TO 120W. THIS CONVECTION IS CONTRIBUTING TO THE 
MOISTURE PLUME ADVECTING OVER CENTRAL MEXICO.

SURFACE...
STRONG RIDGE IS NORTH OF THE ITCZ WEST OF 115W. STRONG TRADE 
WINDS OF 20 TO 25 KNOTS OCCASIONALLY TO 30 KNOTS ARE ASSOCIATED 
WITH THIS RIDGE.  ELSEWHERE BROAD TROUGH IS ANALYZED.

GAP WINDS TO 20 KNOTS WILL CONTINUE AT LEAST THROUGH 48 HOURS 
IN THE GULF OF PAPAGAYO REGION. 

EXTENDED OUTLOOK...APPEARS A MAJOR WIND EVENT IS SETTING UP FOR 
THE GULF OF TEHUANTEPEC GAP IN THE WAKE OF A STRONG COLD FRONT 
IN THE GULF OF MEXICO TUE EVENING.

NORTHWEST WINDS IN THE GULF OF CALIFORNIA WILL FLUCTUATE AROUND 
20 KT DURING THE NEXT 48 HOURS.

$$
LL