000
AXPZ20 KNHC 310339
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU DEC 31 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 
0315 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS CENTERED ALONG 4N77W 7N90W
5N110W 5N120W 5N125W 7N140W. NO SIGNIFICANT CONVECTION IS NOTED.
  
...DISCUSSION...

A SHORTWAVE RIDGE EXTENDS OVER THE EXTREME NW CORNER OF THE 
DISCUSSION OF THE AREA WITH UPPER LEVEL MOISTURE SPILLING OVER
THE TOP OF THE RIDGE SOUTHEASTWARD INTO THE FAR NW PART. A LARGE 
MID/UPPER TROUGH EXTENDS FROM THE GREAT PLAINS REGION OF THE 
U.S. SW ACROSS NORTHERN MEXICO TO A DEVELOPING UPPER LEVEL LOW
NEAR 24N115W...THEN SW TO 18N125W THEN S TO 11N122W. THE UPPER 
LOW IS FORECAST TO MOVE NE TOWARDS SOUTHERN BAJA THEN BECOME 
DIFFUSE. CONFLUENT FLOW INTO THE BACK SIDE OF THE TROUGH IS 
RESULTING IN MODERATE SUBSIDENCE WITH ASSOCIATED DRY STABLE 
CONDITIONS TO THE N OF THE TROUGH. SOME HIGH LEVEL MOISTURE IN 
THE FORM OF SCATTERED CIRRUS CLOUDS IS SPREADING S OVER THE FAR 
NE PORTION OF THE AREA.

AN UPPER RIDGE ORIGINATING OVER S AMERICA RIDGES NW OVER THE 
WESTERN CARIBBEAN AND MOST OF CENTRAL AMERICA. UPPER MOISTURE 
ORIGINATING FROM ITCZ CONVECTION BETWEEN 115W AND 135W IS BEING 
ADVECTED NE VIA A STRONG SUBTROPICAL JET STREAM NORTHEASTWARD 
TOWARDS CENTRAL MEXICO AND WELL NE ACROSS THE SE U.S. MAXIMUM
JET STREAM CORE WINDS ARE IN THE RANGE OF 60-110 KT FROM 13N-19N
BETWEEN 107W-115W.

AN UPPER LEVEL TROUGH EXTENDS FROM 12N102W TO NEAR 1N103W...
AND EARLIER WAS ENHANCING CONVECTION FROM 7N-10N BETWEEN 97W
-101W. PLENTY OF SURROUNDING DRY AIR ALOFT IS HAS DRIED MUCH
OF THE REMAINING DEBRIS MOISTURE.

AT THE SURFACE...HIGH PRES OF 1025 MB IS CENTERED NEAR 30N128W
WITH A RIDGE SE TO NEAR 21N115W. HIGH PRES COVERS THE AREA N OF 
12N W OF 110W. 

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS OF 20 TO 30 KT ARE FORECAST TO 
DIMINISH TO LESS THAN 20 KT LATE THU NIGHT...THEN RAPIDLY 
INCREASE TO GALE FORCE LATE FRI AFTERNOON INTO FRI EVENING AS 
STRONG HIGH PRES PRESSES SOUTHWARD OVER SOUTHERN TEXAS INTO 
EASTERN MEXICO ALLOWING FOR THE PRES GRADIENT TO SIGNIFICANTLY
TIGHTEN ACROSS SE MEXICO. LATEST MODEL WIND GUIDANCE SUGGESTS
THAT WINDS COULD INCREASE UP TO 40 KT...MAYBE POSSIBLY SLIGHTLY
HIGHER...FRI NIGHT.

GULF OF PAPAGAYO...NE TO E WINDS OF 20 TO 25 KT ARE EXPECTED TO 
CONTINUE THROUGH THU...THEN INCREASE POSSIBLY UP TO 30 KT 
THROUGH FRI EVENING.

GULF OF CALIFORNIA...NW WINDS ARE EXPECTED TO 20 KT ARE POSSIBLE
OVER THE SOUTHERN TIER OF THE GULF. THESE WINDS ARE EXPECTED
TO THROUGHOUT THE GULF BY THU NIGHT WITH LITTLE CHANGE INTO 
FRI NIGHT.

SEA CONDITIONS ARE DOMINATED BY LONG PERIOD NW SWELL (WAVE 
PERIODS OF UP TO 16 SECONDS) WITH SIGNIFICANT WAVE HEIGHTS AS 
HIGH AS 12 FT. 

FOR ADDITIONAL INFORMATION PLEASE VISIT 
HTTP://WWW.HURRICANES.GOV/MARINE
  
$$
AGUIRRE