000
AXPZ20 KNHC 210942
TWDEP 

TROPICAL WEATHER DISCUSSION    
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC SAT FEB 21 2009

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 
0930 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE FROM 05N77W 
T0 03N90W TO 06N120W TO 07N140W. NO SIGNIFICANT CONVECTION 
NOTED. 

...DISCUSSION...

RATHER SHARP MID-UPPER LEVEL TROUGH EXTENDS FROM A STRONG 
COMPLEX CUTOFF LOW CENTERED WELL N OF THE AREA NEAR 38N137W 
JUST NW OF THE AREA TO ANOTHER UPPER LEVEL CYCLONE AT THE BASE 
OF THE TROUGH NEAR 32N143W. STRONG UPPER LEVEL SUBSIDENCE WAS 
WRAPPING AROUND THE W SIDE OF THE BASE OF THE TROUGH JUST W OF 
THE FAR NW CORNER OF THE DISCUSSION AREA. THE CUTOFF LOW AND 
TROUGH WILL CONTINUE THROUGH THE NEXT SEVERAL DAYS WITH THE 
TROUGH SWEEPING ACROSS THE NORTHWEST PORTION OF THE DISCUSSION 
AREA BY 48 HOURS. 

A BROAD AMPLIFYING MID-UPPER LEVEL RIDGE COVERS THE REMAINDER
OF THE AREA WEST OF 110W. ALTHOUGH THE UPPER LEVEL FLOW WAS 
DIFFLUENT OVER THE SW PORTION OF THE RIDGE...THERE WAS VERY 
LITTLE IN THE WAY OF ITCZ RELATED CONVECTION. A BROAD AREA
OF STRONG SW FLOW AT THE UPPER LEVELS WAS ADVECTING A PLUME OF 
MOISTURE WITH SOME MIDDLE AND UPPER LEVEL CLOUDS WITHIN 
4800 NM EITHER SIDE OF A LINE FROM 17N140W TO CENTRAL BAJA 
CALIFORNIA PENINSULA. THIS MOISTURE IS EMANATING FROM ITCZ 
CONVECTION LOCATED WEST OF 140W TO A VERY DEEP TROPICS TROUGH S 
OF THE HAWAIIAN ISLANDS. ANOTHER AREA OF MOISTURE AND MULTI 
LEVEL BROKEN TO OVERCAST CLOUDS IS MOVING OVER CENTRAL MEXICO 
BETWEEN 20N AND 26N. THIS MOISTURE ALSO ORIGINATED FROM ITCZ 
CONVECTION AND WAS BEING ENHANCED DOWNSTREAM OF AN UPPER LEVEL 
TROUGH LOCATED OVER MEXICO ALONG 103W. 

SURFACE COLD FRONT IS OVER THE NORTHWEST PART OF THE AREA 
EXTENDING FROM 30N134W TO 25N140W AND WAS MOVING SE AT 10-15 KT. 
THIS FRONT IS ASSOCIATED WITH THE MIDDLE AND UPPER LEVEL TROUGH 
AND CUTOFF NOTED ABOVE. THE SURFACE FRONT SHOULD CONTINUE E AND 
WEAKEN OVER THE NEXT SEVERAL DAYS. OTHERWISE WEAK RIDGE IS NORTH 
OF 15N W OF 105W. 

GAP WINDS...
A 2350 UTC HIGH RESOLUTION QUIKSCAT PASS INDICATED NE TO E 
GAP WINDS OF 20 TO 30 KNOTS WITHIN 90-120 NM OF THE GULF OF 
PAPAGAYO. WINDS SHOULD CONTINUE THROUGH THE DAY TODAY THEN  
DIMINISH TO 20 TO 25 KT SUNDAY. 

ALTHOUGH SCATTEROMETER PASSES MISSED THE REGION...NORTHERLY GAP 
WINDS CONTINUE IN THE GULF OF TEHUANTEPEC REGION BASED ON 
RAPID COOLING OF GOES DERIVED HOURLY SEA SURFACE TEMPERATURES
IN THE AREA SUGGESTING STRONG UPWELLING DUE TO THE NORTHERLY 
WINDS. WINDS WILL DROP OFF RAPIDLY OVER THE NEXT 12 HOURS THEN 
INCREASE AGAIN EARLY SUNDAY AND REACHING GALE FORCE BY SUNDAY 
EVENING RESULTING IN THE FIRST GALE EVENT IN TWO WEEKS. 

$$
COBB