000
AXPZ20 KNHC 280317
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT FEB 28 2009

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 
0300 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 05N77W 
TO 03N100W TO 06N130W TO 06N140W. NO SIGNIFICANT CONVECTION 
NOTED ALONG ITCZ.

...DISCUSSION...

W OF 115W...A CUTOFF UPPER CYCLONE THAT WAS LOCATED NE OF HAWAII 
IS NOW LIFTING OUT TO THE NE AS A DEEP MID/UPPER TROUGH DIGS N 
OF THE AREA ALONG 140W. STRONG NORTHERLY UPPER FLOW MOVING INTO 
THE BASE OF THE TROUGH IS SUPPORTING A 1011 MB SURFACE LOW PRES 
CENTER NEAR 31N140W. A COLD FRONT IS ANALYZED FROM THE LOW TO 
23N140W THEN TO THE SE OF HAWAII. SCATTEROMETER DATA SHOW 20 TO 
30 KT SOUTHERLY WINDS AHEAD OF THE FRONT...MAINLY N OF 25N. IR 
SATELLITE IMAGERY SHOWS SCATTERED CONVECTION AHEAD OF THE FRONT 
AS WELL. STRONG GUSTS ARE PROBABLE AMID THIS CONVECTION. THE 
PATTERN BECOMES HIGHLY AMPLIFIED OVER THE NEXT COUPLE OF DAYS AS 
THE TROUGH CUTOFF N OF THE AREA AND STRONG RIDGING BUILDS OVER 
THE WESTERN U.S. THE FRONT MAKES ONLY MODEST EASTWARD 
PROGRESSION AS THE SUPPORTING UPPER TROUGH CUTS OFF...BUT 
SOUTHERLY WINDS TO 30 KT PERSIST INTO SAT BETWEEN THE SURFACE 
LOW AND HIGH PRES OFF THE CALIFORNIA COAST. THE EMERGENCE OF THE 
TROUGH/FRONT E OF 140W ALLOWS PERSISTENT TRADES S OF 15N TO 
DIMINISH SLIGHTLY FRI INTO SAT. CONTINUING NW SWELL WILL BE 
REINFORCED HOWEVER INTO SUN MAINLY W OF 120W. FRESH NORTHERLY 
FLOW BETWEEN THE BAJA COAST AND THE SURFACE HIGH PRES DIMINISHES 
AS THE HIGH PRES SHIFTS FURTHER NORTH. 

E OF 115W...LIGHT FLOW OVER GULF OF TEHUANTEPEC WILL PICK UP 
DRAMATICALLY BY EARLY SUN IN RESPONSE TO A COLD FRONT PUSHING 
INTO THE GULF OF MEXICO AND THROUGH THE TEHUANTEPEC ISTHMUS BY 
SAT NIGHT. WINDS WILL REACH GALE FORCE SUN DUE THE COLD DENSE 
AIR FUNNELING THROUGH THE GAP. PERSISTENT FRESH TO STRONG FLOW 
THROUGH PAPAGAYO SHOWS NO SIGNS OF ABATING AS WELL THROUGH THE 
WEEKEND. WINDS IN GULF OF CALIFORNIA INCREASE TO 20 TO 25 KT SAT 
AS WELL...AS STRONG HIGH PRES BUILDS OVER THE GREAT BASIN. THE 
HIGH PRES SHIFTS EASTWARD THROUGH THE ROCKIES THROUGH LATE 
SUNDAY...ALLOWING WINDS FUNNELING INTO THE NORTHERN GULF OF 
CALIFORNIA TO DIMINISH.

$$
CHRISTENSEN