000
AXPZ20 KNHC 272157
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC SUN FEB 27 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 06N77W 
TO 00N98W...REMAINS S OF THE EQUATOR ALONG 02S BETWEEN 100W AND 
109W...THEN CROSSES THE EQUATOR AT 110W CONTINUING W TO BEYOND 
04N140W. SCATTERED MODERATE AND ISOLATED STRONG CONVECTION IS 
CONFIRMED BY LIGHTNING DATA OVER THE DISCUSSION AREA FROM 03N TO 
09N BETWEEN 79W AND 91W.

...DISCUSSION...

AN UPPER LEVEL CYCLONE IS NEAR 30N146W WITH A NEGATIVE TILT 
UPPER TROUGH EXTENDING SE TO 27N132W. CONVECTION WAS ENHANCED 
EARLIER JUST W OF THE AREA AT 25N144W. THE DEBRIS MOISTURE IS 
NOW SPREADING NE ALONG THE UPPER TROUGH...ROUGHLY COVERING THE 
DISCUSSION AREA FROM 22N TO 29N BETWEEN 126W AND 146W.

A DEEP LAYERED CYCLONE IS LIFTING NE ACROSS NORTHWESTERN NEW 
MEXICO TRAILING A MID TO UPPER TROUGH SW FROM 32N111W TO A BASE 
NEAR 26N125W. DRY UPPER AIR IS OBSERVED N OF 29N E OF 130W. THE 
ASSOCIATED SURFACE COLD FRONT EXTENDS ACROSS THE GULF OF 
CALIFORNIA FROM 27N111W TO THE BAJA CALIFORNIA PENINSULA AT 
26N112W...AND CONTINUES WSW TO NEAR 24N130W. THE POST FRONTAL 
GRADIENT WILL INCREASE THE NW SURFACE WINDS TO 20 KT OVER THE 
GULF OF CALIFORNIA THROUGH EARLY MON NIGHT. NORTHERLY WINDS AT 
15 TO KT ALSO ACCOMPANY THE FRONT ALONG THE W COAST OF THE BAJA 
CALIFORNIA PENINSULA TONIGHT...WITH SEAS 8 TO 14 FT IN LONG 
PERIOD NW SWELL OVER THE PACIFIC WATERS N OF 22N BETWEEN 112W 
AND 140W. THESE SEAS ARE FORECAST TO SUBSIDE TO LESS THAN 8 FT 
IN 48W HOURS OVER THE E PORTION...BUT WILL INCREASE OVER THE NW 
PORTION AS A SECOND FRONT ARRIVES TUE PRECEDED BY SOUTHERLY 
WINDS OF 20 TO 25 KT...PERHAPS EVEN 30 KT...AND ANOTHER BOUT OF 
NW LONG PERIOD SWELLS. 

AN UPPER RIDGE EXTENDS NE FROM THE SOUTHERN HEMISPHERE OVER THE 
DEEP TROPICS ALONG 02N138W TO A SHARP CREST AT 09N127W AND IS 
ACCOMPANIED BY DRY UPPER AIR. AN UPPER TROUGH IS NOTED OVER THE 
DEEP TROPICS FROM 00N125W TO 08N119W. A FEW CLUSTERS OF MODERATE 
CONVECTION WAS ENHANCED EARLIER ALONG THIS TROUGH WITH THE 
DEBRIS MOISTURE NOW EVAPORATING WITHIN 90 NM OF LINE 08N117W TO 
02N127W. AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 19N96W WITH 
AN UPPER RIDGE EXTENDING SW TO 10N125W. A WELL DEFINED TROPICAL 
MOISTURE PLUME IS ADVECTED NE IN A SOUTHWESTERLY JET ALONG THE 
NW PERIPHERY OF THE UPPER RIDGE...ALL WITHIN 360 NM EITHER SIDE 
OF LINE FROM 12N148W TO 25N123W. THE PLUME THEN NARROWS AND 
ALMOST COMPLETELY EVAPORATES JUST BEFORE CROSSING OVER THE THE 
BAJA CALIFORNIA PENINSULA AT 26N112W. DENSE DEBRIS MOISTURE 
ORIGINATING FROM CONVECTION OVER COLOMBIA AND THE ITCZ 
CONVECTION PREVIOUSLY DESCRIBED...IS NOTED S OF 10N E OF 92W. 
OTHERWISE THE UPPER LEVELS ARE VERY DRY S OF 22N E OF 120W.     
 
ELSEWHERE AT THE SURFACE...A RIDGE IS BRIDGING THE DECAYING COLD 
FRONT ALONG 24N BETWEEN 120W AND 130W. THE PRESSURE GRADIENT SW 
OF THE RIDGE AND N OF THE ITCZ IS MAINTAINING A SMALL AREA OF 
FRESH TRADE NE WINDS FROM 07N TO 11N W OF 120W. THESE TRADES 
WILL MIGRATE N TO THE AREA FROM 07N TO 17N W OF 125W ON 
MON...THEN MIGRATE E TO THE AREA FROM 08N TO 14N BETWEEN 115W 
AND 130W ON TUE.

GULF OF PAPAGAYO...NE TO E WINDS WILL CONTINUE TO PULSE AT 15 TO 
20 KT THROUGH TUE MORNING...WITH ENHANCED DRAINAGE FLOW OFF 
THE CENTRAL AMERICA LANDMASS LATE AT NIGHT THROUGH EARLY 
MORNING.

GULF OF TEHUANTEPEC...A COLD FRONT WILL SWEEP SE ACROSS THE GULF 
OF MEXICO ON MON. NORTHERLY WINDS WILL INCREASE TO 15 TO 20 KT 
IN THE GULF OF TEHUANTEPEC EARLY MON NIGHT...FURTHER INCREASING 
TO MINIMAL GALE FORCE JUST AFTER SUNRISE TUE MORNING... 
CONTINUING TO JUST AFTER SUNRISE WED MORNING....THEN QUICKLY 
DIMINISH WED AFTERNOON.       

$$
NELSON