000
AXPZ20 KNHC 280928
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC THU FEB 28 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

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

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH FROM 9N84W 4N90W TO 2N110W. ITCZ FROM 2N110W TO 
4N120W TO 1N140W. NO SIGNIFICANT CONVECTION.

...DISCUSSION...
NEARLY STATIONARY UPPER LEVEL TROUGH OVER THE FAR NW PORTION OF 
THE DISCUSSION AREA WITH AXIS EXTENDING FROM FROM A BROAD 
CYCLONIC CIRCULATION CENTERED NEAR 30N133W SW TO 22N140W. A 
BROAD FLAT UPPER LEVEL RIDGE IS E OF THE TROUGH N OF 20N BETWEEN 
110W AND 130W. A 95-105 KT JETSTREAM OVER THE TOP OF THE RIDGE 
FROM  28N133W TO TO NORTHERN BAJA CALIFORNIA WHERE WINDS 
INCREASE TO 120-130 KT. A DENSE LAYER OF OVERCAST CLOUDS ARE 
WITHIN 660 NM S OF THE JET WITH EMBEDDED SHOWERS W OF 130W. IN 
THE DEEP TROPICS AN UPPER LEVEL TROUGH EXTENDS FROM 10N116W SE 
TO 2N100W. MODERATE TO STRONG SUBSIDENCE WITH DRY AND STABLE AIR 
AT THE MIDDLE AND UPPER LEVELS IS FROM 10N-20N E OF 110W.

SURFACE RIDGE IS N OF 15N W OF 115W. THE PRES GRADIENT ALONG THE 
SOUTHERN PERIPHERY OF THE RIDGE IS STRONG ENOUGH TO SUPPORT ELY 
20-25 KT WINDS FROM 15N-20N W OF 130W. THE RIDGE IS FORECAST TO 
WEAKEN SOME WITH AN DECREASING TO 20 KT OR LESS SAT. HOWEVER 
LARGE NLY SWELLS WILL CONTINUE THROUGH THE WEEKEND.

NLY WIND 20-30 KT CONTINUE TO BLOW THROUGH THE GULF OF 
CALIFORNIA AND ARE FORECAST TO CONTINUE THROUGH SAT.

STRONG HIGH PRES BUILDING SOUTHWARD BEHIND A COLD FRONT MOVING 
THROUGH THE GULF OF MEXICO WILL TIGHTEN THE PRES GRADIENT ACROSS 
SOUTHERN MEXICO. AS A RESULT NLY WIND INCREASE TO 20-25 KT IN 
THE GULF OF TEHUANTEPEC TODAY. THE GRADIENT MAY TIGHTEN EVEN 
FURTHER FRI AND GALE FORCE WINDS ARE FORECAST THROUGH THE GULF 
OF TEHUANTEPEC. WINDS MAY INCREASE TO STORM FORCE OVER THE 
WEEKEND.

$$
DGS