000
AXPZ20 KNHC 110939
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC TUE JAN 11 2011

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 AXIS IS ALONG 07N78W TO 
04N95W TO 11N110W THEN RESUMES AT 10N115W TO 07N130W TO 06N140W. 
SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS NOTED FROM 
05N TO 07N BETWEEN 78W AND 81W. SCATTERED MODERATE CONVECTION IS 
NEAR 09N115W...AND NEAR 08N125W.

...DISCUSSION...

WELL DEFINED MID TO UPPER LEVEL LOW AND ASSOCIATED TROUGH WELL 
N OF THE AREA EXTENDS FROM 40N135W SE TO 32N134W. THIS TROUGH 
IS PROVIDING MARGINAL SUPPORT FOR A WEAKENING STATIONARY FRONT 
WHICH EXTENDED FROM 30N136W TO 26N140W. THE FRONT IS FORECAST TO 
DISSIPATE OVER FORECAST WATERS LATE TODAY. THE S TO SW WINDS OF 
20 KT FOUND N OF 28N BETWEEN 130W AND 136W WILL GRADUALLY WEAKEN 
AS THE FRONT DISSIPATES. ANOTHER COLD FRONT WILL APPROACH TO THE 
FAR NW CORNER OF THE AREA TUE NIGHT INTO WED INCREASING WINDS TO 
20 TO 25 KT.

A SURFACE RIDGE CONTINUES TO DOMINATES THE REMAINDER OF THE 
REGION N OF 15N. THE GRADIENT BETWEEN THE RIDGE AND LOWER 
PRESSURES OVER MEXICO HAS WEAKENED AND THE AREA OF 20 KT WINDS 
ALONG THE BAJA CALIFORNIA COAST HAS DIMINISHED. HOWEVER AS 
STRONG HIGH PRESSURE BUILDS OVER THE GREAT BASIN OVER THE NEXT 
24 TO 48 HOURS NW TO N WINDS WILL INCREASE TO 20 TO 25 KT IN THE 
GULF OF CALIFORNIA WITHIN 24 HOURS...AND TO 30 KT BY 48 HOURS. 

AN AREA OF FRESH TRADE WINDS CAN BE FOUND ON THE SOUTHERN 
PERIPHERY OF THE RIDGE FROM 07N TO 20N W OF 115W. THE 0506 UTC 
ASCAT PASS CORROBORATED THE PRESENCE OF THESE WINDS. THIS 
WEATHER PATTERN WILL PERSIST OVER THE NEXT COUPLE OF DAYS. THE 
AERIAL EXTENT AND STRENGTH OF THE TRADES WILL INCREASE BY 48 
HOURS AS HIGH PRES STRENGTHENS. A 1029 MB HIGH WILL BE LOCATED 
NEAR 32N126W. 
 
A SURFACE TROUGH EXTENDS FROM 14N111W TO 08N114W. NE WINDS OF 20 
KT ARE OCCURRING WITHIN 150 NM W OF THE TROUGH AXIS FROM 08N TO 
13N. THE ASCAT PASS FROM 0506 UTC SHOWED NE WINDS OF 20 KT NEAR 
THE NORTHERN END OF THE TROUGH AXIS. 

ELSEWHERE IN THE AREA...LONG PERIOD NW SWELL CONTINUES TO 
PROPAGATE SE ACROSS THE EAST PACIFIC COVERING MOST OF THE AREA W 
OF 90W. PERIOD OF 18 TO 20 SECONDS ARE NOTED AT THE LEADING EDGE 
OF THE SWELL TRAIN WHICH IS IMPACTING THE GALAPAGOS ISLANDS. 
A NEW SWELL TRAIN HAS ENTERED THE FAR NW PORTION OF THE AREA AND 
WILL TRAVERSE THE AREA LATER TODAY AND WED. 

GAP WINDS...
STRONG ARCTIC HIGH PRESSURE IS EXPECTED TO BUILD DOWN THE COAST 
OF MEXICO EAST OF THE SIERRA MADRE LATER TODAY. THE ASSOCIATED 
SURGE OF DENSE COLD AIR IS EXPECTED TO FUNNEL THROUGH THE 
CHIVELA PASS INTO THE GULF OF TEHUANTEPEC RESULTING IN GALE 
FORCE WINDS WITHIN 18 HOURS. THE NAM AND THE GFS MODELS FORECAST 
NLY WINDS OF 30 TO 45 KT WED AFTERNOON...AND A FURTHER INCREASE 
OF THE WINDS TO STORM FORCE...50 KT...BY WED NIGHT WITH SEAS 
BUILDING UP TO 18 FT. A STORM WARNING HAS BEEN ISSUED FOR THE 
GULF OF TEHUANTEPEC WITHIN 48 HOURS. 

WINDS ARE BEGINNING TO INCREASE ACROSS THE GULF OF PAPAGAYO AS 
EASTERLY SURGES IN THE SOUTHWESTERN CARIBBEAN SEA BLOW THROUGH 
THE PASSES. THE 0324 ASCAT PASS SHOWED A FEW WIND BARBS OF 20 KT 
THERE. THE WINDS WILL BECOME MORE ENHANCED AND INCREASE TO 25 KT 
BY LATE WED AS THE COLD SURGE IN THE TEHUANTEPEC MAKES ITS WAY 
DOWN THROUGH CENTRAL AMERICA.  

$$
GR