000
AXPZ20 KNHC 192132
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC WED JAN 19 2011

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS CENTERED ALONG 06N77W 
TO 04N100W TO 10N120W TO 09N140W. ISOLATED MODERATE CONVECTION 
NEAR 04N79W AND WITHIN 60 NM S OF AXIS FROM 85W TO 88W.  

...DISCUSSION...
A 1032 MB HIGH PRES CENTERED NEAR 40N136W EXTENDS A RIDGE SE 
OVER THE FORECAST WATERS TO NEAR 19N110W. THE PRES GRADIENT 
BETWEEN THIS HIGH AND LOWER PRESSURE ASSOCIATED WITH THE ITCZ 
SUPPORTS FRESH TRADE WINDS TO 20 KT FROM 09N TO 13N W OF 132W. 
THE SURFACE HIGH PRESSURE IS FORECAST TO REMAIN STATIONARY OVER 
THE NEXT 24 HOURS WHICH WILL MAINTAIN THIS AREA OF FRESH TRADES. 
THE PRESSURE GRADIENT BETWEEN THE SURFACE HIGH MENTIONED ABOVE 
AND THE CALIFORNIA COASTAL TROUGH IS SUPPORTING FRESH TO STRONG 
N TO NE WINDS N OF 25N W OF 122W. THESE WINDS ARE FORECAST TO 
REMAIN THROUGH 24 HOURS...THEN DIMINISH TO 20 KT WITHIN 48 
HOURS. 

LARGE LONG PERIOD NW SWELLS WITH PERIODS OF 15-17 SEC ARE 
PRODUCING SEAS OF 8 TO 12 FT OVER THE NW PART OF THE AREA. A 
SECOND SET OF NW SWELLS WILL FURTHER INCREASE THE SEAS TO NEAR 
15 FT OVER THE FAR NW PART OF THE AREA BY FRI MORNING. 

GAP WINDS...
BASED ON VISIBLE SATELLITE IMAGERY THAT REVEALS A WELL DEFINED 
ROPE CLOUD MOVING DOWNSTREAM OF THE GULF OF TEHUANTEPEC...WHICH 
LIKELY DELINEATES THE LEADING EDGE OF THE CURRENT GAP WIND EVENT 
AND SURFACE OBSERVATIONS FROM IXTEPEC MEXICO WHICH IS REPORTING 
SUSTAINED WINDS OF 25 TO 30 KT SINCE 1600 UTC...DECIDED TO 
INCLUDE A GAP WIND EVENT THROUGH THE GULF OF TEHUANTEPEC ON THIS 
PACKAGE. WINDS ARE FORECAST TO DIMINISH TO 20 KT BY THU AS WINDS 
ACROSS THE GULF OF MEXICO VEER TO THE SOUTH. 

THE NEXT GULF OF TEHUANTEPEC EVENT IS THEN FORECAST TO BEGIN ON 
FRI AS HIGH PRES BUILDS S ACROSS MEXICO AND THE WESTERN GULF OF 
MEXICO IN THE WAKE OF A COLD FRONT THAT MOVES THROUGH THE BAY OF 
CAMPECHE AND SOUTHEASTERN MEXICO WITH THE POSSIBILITY OF A BRIEF 
EPISODE OF WINDS REACHING MINIMAL GALE FORCE.

WINDS ARE EXPECTED TO INCREASE TO 20 KT OVER THE FAR NORTHERN 
PORTION OF THE GULF OF CALIFORNIA BEGINNING ON THU AS STRONG 
HIGH PRES BUILDS OVER THE GREAT BASIN REGION. 

$$
GR