000
AXPZ20 KNHC 151548
TWDEP 

TROPICAL WEATHER DISCUSSION  
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC TUE MAR 15 2011

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1545 UTC.

...ITCZ...
THE INTERTROPICAL CONVERGENCE ZONE AXIS IS ANALYZED FROM 04N77W 
TO 02N85W TO 05N105W TO 04N140W. SCATTERED MODERATE CONVECTION 
IS FLARING WITHIN 30 NM EITHER SIDE OF A LINE FROM 08N84W TO 
04N89W TO 07N105W. SCATTERED MODERATE AND ISOLATED STRONG 
CONVECTION IS OBSERVED FROM 03N TO 10N BETWEEN 108W AND 144W. 

...DISCUSSION...
A COUPLE OF UPPER TROUGHS ARE PASSING E ACROSS THE NORTHERN 
PORTION. THE WESTERNMOST TROUGH EXTENDS FROM 32N120W TO 17N131W. 
THE EASTERNMOST TROUGH EXTENDS INTO THE DISCUSSION AREA FROM 
32N96W TO 12N100W. AN UPPER ANTICYCLONE IS CENTERED AT 10N111W 
WITH AN UPPER RIDGE EXTENDING N AND CRESTING BETWEEN THE TWO 
AFOREMENTIONED TROUGHS AT 23N116W. UPPER MOISTURE IS SPREADING E 
OVER THE AREA N OF 28N W OF 111W WITH SOME MOISTURE NOW PASSING 
E ACROSS WESTERN NEW MEXICO. DEBRIS MOISTURE FROM THE ITCZ 
CONVECTION BETWEEN 110W AND 150W SPREADS N BETWEEN 120W AND 145W 
CONCENTRATING INTO A BAND THAT CONTINUES NE TO NEAR 18N112W 
WHERE THE MOISTURE EVAPORATES. A BAND OF VERY DRY AIR ALOFT IS 
INDICATED WITHIN 180 NM OF LINE 20N140W TO 24N120W T0 20N105W 
MERGING WITH UPPER DRY AIR DOMINATING THE DISCUSSION AREA TO THE 
S OF 20N E OF 110W. THE UPPER RIDGE IS EXPECTED TO COLLAPSE 
FURTHER S...ALLOWING THE WESTERNMOST TROUGH TO CONTINUE EASTWARD 
WITH A NEW UPPER RIDGE BUILDING E ALONG 20N W OF 120W WED. A 
THIRD UPPER TROUGH WILL SWING SE INTO THE NW PORTION TO THE N OF 
THE RIDGE THU WHILE THE SECOND TROUGH FILLS SLIGHTLY ACROSS 
NORTHERN OLD MEXICO AND THE SOUTHERN BAJA CALIFORNIA PENINSULA.

AT THE LOW LEVELS HIGH PRESSURE IS CENTERED AT 28N131W RIDGING 
SE TO NEAR 17N110W AND RIDGING SW TO NEAR 27N140W. THE HIGH IS 
FORECAST TO DRIFT S AND BE ABSORBED BY A DEEP LAYERED RIDGE 
BUILDING E ALONG 28N OVER THE NEXT COUPLE OF DAYS. A COLD FRONT 
WILL RACE INTO THE NW WATERS TONIGHT...AND CONTINUE E TO THE N 
OF THE RIDGE AXIS...DISSIPATING WED NIGHT. NORTHERLY WINDS ARE 
AT 20 TO 25 KT N OF 25N E OF 122W TO THE WESTERN COAST OF THE 
BAJA CALIFORNIA PENINSULA. ALTHOUGH CLOCKING WINDS ARE LESS THAN 
20 KT ELSEWHERE IN THE SUBTROPICS...LONG PERIOD NW SWELLS RESULT 
IN SEAS TO 14 FT. NE TRADES ARE ENHANCED AT 15 TO 20 KT SW OF 
THE RIDGE...GENERALLY FROM 06N TO 21N W OF 120W WITH SEAS 8 TO 
12 FT IN MIXED NE AND NW SWELL. ELSEWHERE FROM 05N TO 21N W OF 
106W SEAS ARE 7 TO 11 FT IN MIXED NE AND NW SWELL. SOUTHWESTERLY 
SWELL IS EXPECTED TO CROSS THE EQUATOR MIXING WITH THE CROSS NW 
AND NE SWELL OVER THE WATERS S OF THE ITCZ TO THE W OF 100W 
DURING THE NEXT FEW DAYS. A NEW TRAIN 0F LONG PERIOD NW 
SWELLS...DRIVING SEAS UP TO 18 FT...WILL PUSH INTO THE NW 
PORTION TONIGHT AND SPREAD SE ACROSS THE WATERS W OF 100W 
THROUGH THE END OF THE WEEK.

GAP WINDS...
GULF OF TEHUANTEPEC...N WINDS WILL FUNNEL THROUGH THE ISTHMUS OF 
TEHUANTEPEC AT 20 TO 25 KT...MOSTLY DURING THE MORNING HOURS... 
WITH LITTLE CHANGE EXPECTED THROUGH FRI MORNING.

GULF OF PAPAGAYO...DRAINAGE FLOW OFF THE LANDMASS WILL MAINTAIN 
WINDS AT 20 KT DURING THE EARLY MORNING HOURS FOR THE NEXT FEW 
DAYS.

GULF OF PANAMA...THERE IS FAINT EVIDENCE OF A WEAK SURFACE LOW 
OVER THE GULF OF PANAMA THIS MORNING WITH A COUPLE OF SHIPS 
REPORTING NW WINDS AT ABOUT 20 KT. EXPECT THE LOW PRES TO FILL 
TONIGHT AS N TO NE WINDS BEGIN TO SURGE AGAIN AT 15 TO 20 KT.

$$
NELSON