000
AXPZ20 KNHC 282202
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC MON FEB 28 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 
2145 UTC.

...ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 07N77W 
TO 00N98W...THEN RE-ENTERS THE NORTHERN HEMISPHERE AT 00N105W 
CONTINUING NW TO 07N122W...TURNS SW TO 03N133W...THEN NW TO 
BEYOND 06N140W. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS 
NOTED WITHIN 120 NM EITHER SIDE OF A LINE FROM 07N78W TO 
04N91W...AND ALSO A LINE FROM 07N122W TO 04N130W. SCATTERED 
MODERATE CONVECTION IS NOTED WITHIN 30 NM OF 02N94W.
 
...DISCUSSION...

TWO UPPER SHORT WAVES ARE PASSING E THROUGH THE AREA N OF 25N 
BETWEEN 125W AND 140W AND DENSE DEBRIS MOISTURE IS SPREADING NE 
ACROSS THIS AREA AS WELL. AN UPPER LEVEL ANTICYCLONE IS CENTERED 
OVER OLD MEXICO AT 20N102W WITH AN UPPER RIDGE EXTENDING SW TO A 
SHARP CREST AT 10N118W. A TROPICAL MOISTURE PLUME IS ADVECTED NE 
ALONG THE NW PERIPHERY OF THIS UPPER RIDGE...ROUGHLY WITHIN 360 
NM EITHER SIDE OF LINE FROM 10N132W TO 30N113W WHERE THE 
MOISTURE IS EVAPORATING AS IT CROSSES OVER THE NORTHERN BAJA 
CALIFORNIA PENINSULA. DEBRIS MOISTURE...ORIGINATING FROM ITCZ 
CONVECTION...IS NOTED WITHIN 120 NM EITHER SIDE OF A LINE FROM 
04N136W TO 05N124W TO 10N118W. DENSE DEBRIS MOISTURE ORIGINATING 
FROM CONVECTION OVER COLOMBIA AND THE ITCZ CONVECTION PREVIOUSLY 
DESCRIBED...IS SPREADING W OVER THE AREA S OF 10N E OF 96W. 
OTHERWISE THE UPPER LEVELS ARE VERY DRY S OF 24N E OF 113W.  

AT THE SURFACE...A COLD FRONT IS APPROACHING THE NW PORTION WITH 
SOUTHERLY FLOW ALREADY AT 15 TO 20 KT OVER THE AREA N OF 24N W 
OF 136W. EXPECT THIS FRONT TO REACH ALONG 30N137W TO 29N140W ON 
TUE WITH THE SOUTHERLY FLOW INCREASING TO 20 TO 30 KT JUST AHEAD 
OF THE FRONT. THE LOW LEVEL FLOW E OF THE FRONT WILL DIMINISH 
WED AS THE FRONT SLOWS ITS EASTWARD PROGRESS...BUT A NEW TRAIN 
OF LONG PERIOD NW SWELLS WILL MOVE INTO THE NW PORTION W OF THE 
FRONT. FURTHER E...HIGH PRESSURE DOMINATES THE SUBTROPICS 
WITH THE GRADIENT SW OF THE RIDGE AND TO THE N OF THE ITCZ 
MAINTAINING A SMALL AREA OF 15 TO 20 KT NE WINDS...ROUGHLY FROM 
07N TO 13N BETWEEN 115W AND 133W. THESE TRADES WILL SPREAD N TO 
THE AREA FROM 07N TO 15N BETWEEN 115W AND 132W ON TUE AS THE 
LONG PERIOD N SWELLS DIMINISH OVER THE SUBTROPICAL PACIFIC.  

GULF OF CALIFORNIA...NW WINDS AT 15 TO 20 KT ARE OBSERVED OVER 
THE GULF S OF 30N...BUT EXPECTED TO SHRINK TO THE WATERS S OF 
27N ON TUE AND S OF 25N ON WED.

GULF OF PAPAGAYO...NE TO E WINDS WILL CONTINUE TO PULSE AT 15 TO 
20 KT THROUGH TUE MORNING THEN INCREASE TO 20 TO 25 KT ON WED 
MORNING.

GULF OF TEHUANTEPEC...A COLD FRONT IS SWEEPING SE ACROSS THE 
GULF OF MEXICO AND THE POST FRONTAL NORTHERLY WINDS AT 15 TO 20 
KT WILL SURGE INTO THE GULF OF TEHUANTEPEC EARLY TONIGHT...
INCREASING TO MINIMAL GALE FORCE JUST AFTER SUNRISE TUE 
MORNING...CONTINUING TO JUST AFTER SUNRISE WED MORNING...THEN 
QUICKLY DIMINISHING WED AFTERNOON.       

$$
NELSON