000
AXPZ20 KNHC 070949
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI JAN 07 2011

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS CENTERED FROM 04N80W TO 
08N99W TO 05N117W TO 08N140W. NO SIGNIFICANT CONVECTION IS NOTED.

...DISCUSSION...

A 994 MB LOW IS CENTERED NW OF THE AREA NEAR 32N148W WITH 
ASSOCIATED COLD FRONT WEST OF THE AREA. STATIONARY HIGH PRESSURE 
1026 MB IS CENTERED N OF THE AREA NEAR 38N131W. THE PRESSURE 
GRADIENT BETWEEN THESE FEATURES IS PRODUCING FRESH TO STRONG SE 
TO S WINDS IN THE FAR NW PART OF THE FORECAST AREA. A BLOCKING 
PATTERN OVER THE NEXT COUPLE OF DAYS WILL KEEP THE LOW FROM 
MAKING MUCH EASTWARD PROGRESS...MAINTAINING FRESH 20 KT SE TO S 
WINDS OVER THE FAR NW PART OF THE AREA THROUGH 48 HOURS. NW 
SWELLS GENERATED FROM THE LOW WILL PROPAGATE ACROSS THE AREA W 
OF 100W OVER THE NEXT 48 HOURS.  

A WEAK 1021 MB HIGH PRESSURE IS CENTERED NEAR 28N121W. THE 
PRESSURE GRADIENT BETWEEN THIS FEATURE AND TROUGHING OVER 
WESTERN MAINLAND MEXICO IS MAINTAINING A SMALL AREA OF FRESH 
WINDS OVER THE SOUTHERN PORTION OF THE GULF OF CALIFORNIA. THAT 
HIGH PRESSURE CENTER WILL DISSIPATE OVER THE NEXT 24 
HOURS...AND WINDS OVER THE GULF OF CALIFORNIA WILL DIMINISH 
BELOW 20 KT. 

A TROUGH FROM 13N123W TO 08N125W WAS EVIDENT IN THE LATEST 
WINDSAT PASS. THE PRESSURE GRADIENT BETWEEN THE TROUGH AND WEAK 
HIGH PRESSURE TO THE N MENTIONED IN THE PREVIOUS PARAGRAPH IS 
MAINTAINING FRESH WINDS ON EITHER SIDE OF THE TROUGH AS 
INDICATED BY THE LATEST SCATTEROMETER AND RADIOMETER PASSES. THE 
TROUGH WILL DAMPEN OUT OVER THE NEXT 24 HOURS...WITH ASSOCIATED 
WINDS DIMINISHING BELOW 20 KT. 

A WEAK STATIONARY 1011 MB LOW IS CENTERED OVER THE FAR EASTERN 
PORTION OF THE AREA NEAR 05N80W. THERE ARE NO SIGNIFICANT WINDS 
OR SEAS ASSOCIATED WITH THIS LOW. 

GAP WINDS...
BASED ON THE MOST RECENT HOURLY OBSERVATIONS AT THE LAND BASED 
STATION IXTEPEC IN OAXACA MEXICO AND THE LATEST ASCAT 
PASS...WINDS OVER THE GULF OF TEHUANTEPEC APPEAR TO HAVE PEAKED. 
THE LAST OBSERVATION AT IXTEPEC AT 04 UTC WAS 20 KT...DOWN FROM 
35 KT AT 22 UTC THU. THE LATEST HIGH RESOLUTION ASCAT PASS AT 03 
UTC INDICATE WINDS OF 25 KT OVER THE GULF OF TEHUANTEPEC. 
ADDITIONALLY...LATEST ASCAT PASS INDICATES WINDS OVER THE GULF 
OF MEXICO HAVE ALREADY STARTED TO VEER...WHICH WOULD REDUCE THE 
WINDS FUNNELING THROUGH THE CHIVELA PASS INTO THE GULF OF 
TEHUANTEPEC. WINDS OVER THE GULF OF TEHUANTEPEC ARE FORECAST TO 
DIMINISH BELOW 20 KT BY TONIGHT.   

$$
AL