000
AXPZ20 KNHC 291606
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC FRI OCT 29 2010

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 1545 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG 9N85W 9N97W 11N108W
10N116W 13N124W 9N140W. SCATTERED STRONG CONVECTION IS WITHIN 
120 NM N OF THE AXIS BETWEEN 110W-116W...AND WITHIN 30 NM OF AXIS
BETWEEN 87W-89W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION
IS WITHIN 60 NM OF AXIS BETWEEN 117W-120W. SCATTERED MODERATE 
CONVECTION IS WITHIN 120 NM S OF AXIS BETWEEN 124W-127W 
...WITHIN  60 NM N OF AXIS BETWEEN 105W-108W AND BETWEEN
125W-132W.

...DISCUSSION...

A HIGHLY AMPLIFIED NORTHERN STREAM PATTERN HAS USHERED A SURFACE 
COLD FRONT INTO THE NW PORTION ALONG A POSITION FROM WATERS FROM 
NEAR 32N124W TO 26N130W AND DISSIPATING TO 23N140W. OVERCAST TO 
BROKEN LOW AND MID CLOUDS WITH POSSIBLE ISOLATED SHOWERS ARE 
INDICATED BY SATELLITE IMAGERY TO WITHIN 60 NM EITHER SIDE OF 
THE FRONT. WINDS ARE LESS THAN 20 KT ON EITHER SIDE OF THE FRONT 
...HOWEVER THE MAIN PROBLEM WILL BE LARGE NW SWELLS OF UP TO 15 
FT BEHIND THE FRONT N OF 27N...AND IN THE RANGE OF 9 TO 14 FT 
ELSEWHERE W OF FRONT.  WITHIN 120 NM AHEAD OF THE FRONT N OF 26N 
SEAS ARE 8 TO 10 FT ALSO IN NW SWELLS. THE FRONT IS FORECAST TO 
BEGIN TO DISSIPATE THIS AFTERNOON...AND REACH FROM 32N120W TO 
24N130W TO 21N140W IN 24 HOURS THEN MOVE E OF AREA AND DISSIPATE 
IN 48 HOURS AS SEAS SLOWLY SUBSIDE IN DIMINISHING SWELLS.

A 1012 MB SURFACE LOW IS EMBEDDED IN THE ITCZ NEAR 14N122W ALONG 
A SURFACE TROUGH EXTENDING FROM 18N121W TO THE LOW. ONLY 20 KT 
ARE OCCURRING WITHIN 120 NM IN THE NE QUADRANT. THE LOW IS 
FORECAST TO DISSIPATE IN ABOUT 24 HOURS AS WEAK RIDGING BUILDS 
SE ACROSS THE CENTRAL AND NW PORTIONS AS THE FRONT DISSIPATES 
AND ALLOWING FOR WEAK TRADES TO CONTINUE.

AN UPPER LEVEL ANTICYCLONE MOVING E IS OVER FAR NW TEXAS WITH A 
RIDGE EXTENDING SW TO NEAR 21N106W. VERY DRY AIR IS PREVALENT 
UNDER THIS RIDGE N OF 15N BETWEEN 100W AND 118W. A DEEP UPPER 
TROUGH EXTENDS FROM 32N131W TO 26N133W TO 22N140W. SW FLOW 
EXISTS AHEAD OF THIS TROUGH AND W OF THE UPPER RIDGE WITH MID TO 
UPPER LEVEL MOISTURE BEING ADVECTED FROM THE TROPICS UP INTO THE 
SW UNITED STATES. ANOTHER ANTICYCLONE IS CENTERED NEAR 09N139W 
WITH A RIDGE EXTENDING NW TO THE BIG ISLAND OF HAWAII AND E TO 
NEAR 10N126W. UPPER LEVEL DIFFLUENCE ON THE E TO SE SIDE OF THIS 
RIDGE IS AIDING IN THE DEVELOPMENT OF CONVECTION ALONG THE ITCZ.

GAP WINDS...
NORTHERLY WINDS ARE SURGING FROM THE SOUTHERN GULF OF MEXICO 
THROUGH THE CHIVELAS PASS AND INTO THE GULF OF TEHUANTEPEC.
GALE FORCE WINDS HAVE BEGUN THROUGH ISTHMUS OF TEHUANTEPEC. WINDS
ARE EXPECTED TO PEAK AT AROUND 40 KT TONIGHT INTO SAT MORNING
...THEN DIMINISH TO LESS THAN GALE FORCE LATE SAT NIGHT INTO SUN
MORNING. SEAS ARE FORECAST TO BUILD TO 14 FT TONIGHT INTO SAT
MORNING...THEN GRADUALLY SUBSIDE LATER ON SAT THROUGH SUN.

$$
AGUIRRE