000
AXPZ20 KNHC 280345
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC THU MAR 28 2013

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. THE FOLLOWING INFORMATION IS 
BASED ON SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND 
METEOROLOGICAL ANALYSIS.

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0330 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
THE MONSOON TROUGH EXTENDS NW FROM THE COAST OF COLOMBIA AT 
08N78W TO ACROSS SOUTHERN PANAMA...THEN TURNS SW TO 04N93W WHERE 
SCATTEROMETER WINDS INDICATE A TRANSITION TO AN ITCZ. THE ITCZ 
THEN EXTENDS SW TO 01N110W...THEN WIGGLES W TO BEYOND 02N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED WITHIN 
60 NM EITHER SIDE OF A LINE FROM 07N85W TO 04N90W...AND WITHIN 
90 NM EITHER SIDE OF A LINE FROM 06N106W TO 02N112W TO 04N120W.

...DISCUSSION...

GULF OF TEHUANTEPEC...WEAKENING HIGH PRESSURE OVER THE GULF OF
MEXICO WILL MAINTAIN MINIMAL GALE CONDITIONS IN AND DOWNSTREAM 
OF THE GULF OF TEHUANTEPEC THROUGH SUNRISE THU...THEN QUICKLY 
DIMINISH TO 20 TO 25 KT LATE THU AFTERNOON. ALTHOUGH THE 
NORTHERLY WINDS WILL FURTHER DIMINISH TO 10 TO 15 KT EARLY THU 
NIGHT...EXPECT ANOTHER N SURGE TO 20 TO 25 KT LATE THU NIGHT 
CONTINUING THROUGH SUNRISE FRI. ONE LAST SURGE AT ONLY 15 TO 20 
KT IS EXPECTED LATE FRI NIGHT INTO MID MORNING ON SAT. LIGHT AND 
VARIABLE WINDS EXPECTED FROM SAT NIGHT THROUGH MON NIGHT.  
  
GULF OF PAPAGAYO...ENE WINDS ARE AT 20 TO 25 KT THROUGHOUT THE 
GULF OF PAPAGAYO AND EXTENDING AS FAR W AS 09N93W. THE GRADIENT 
WILL INCREASE SUPPORTING 20 TO 30 KT BY SUNRISE THU WITH THE 
WESTERN EXTENT NEAR 08N95W...WITH SEAS GRADUALLY BUILDING TO 12 
FT. THE GRADIENT WILL WEAKEN THU NIGHT WITH WINDS DIMINISHING TO 
20 TO 25 KT...WITH LITTLE CHANGE THEN EXPECTED THROUGH SAT. THE 
GRADIENT WILL RELAX ON SAT NIGHT WITH 15 TO 20 KT WINDS THE 
DOMINATE CONDITIONS...BUT PULSES AT 20 TO 25 KT ARE EXPECTED 
LATE EACH NIGHT TILL JUST AFTER SUNRISE EACH MORNING.

GULF OF PANAMA...NORTHERLY WINDS AT 15 TO 20 KT WILL PERSIST 
THROUGH LATE SAT THEN DIMINISH TO 10 TO 15 KT SAT NIGHT.

THE LARGE SWELLS GENERATED IN AND DOWNSTREAM OF THE GULFS OF 
TEHUANTEPEC AND PAPAGAYO WILL MERGE COVERING THE TROPICAL WATERS 
FROM 04 TO 11N BETWEEN 95W AND 115W BY FRI...WITH COMBINED SEAS 
OF 7 TO 10 FT. THESE SWELLS WILL PROPAGATE W OVER THE WEEKEND 
ACROSS THE WATERS FROM 04N TO 11N BETWEEN 95W AND 120W ON 
SAT...AND BETWEEN 110W AND 130W ON SUN.

A NEGATIVE TILT UPPER TROUGH IS SWINGING E ACROSS THE N PORTION 
WITH ITS MEAN AXIS FROM 32N127W TO A BASE AT 17N118W. THE NEARLY 
ZONAL UPPER FLOW IS ADVECTING UPPER MOISTURE ACROSS THE AREA N 
OF 15N WITH THE PLUME TURNING NE ACROSS THE SOUTHERN TIP OF THE 
BAJA PENINSULA AND THE SOUTHERN GULF OF CALIFORNIA...THEN 
CONTINUING NE ACROSS CENTRAL OLD MEXICO. AN UPPER TROUGH IS 
NOTED S OF 10N ALONG ROUGHLY 113W...AND CONTINUES TO SEPARATE 
THE UPPER FLOW OVER THE DEEP TROPICAL PORTION. WEAK UPPER 
DIFFLUENCE IS ENHANCING THE CONVECTION PREVIOUSLY MENTIONED 
BETWEEN 106W AND 120W...WITH THE RESULTANT UPPER DEBRIS MOISTURE 
ADVECTED NE WITHIN 150 NM EITHER SIDE OF A LINE FROM 05N109W TO 
OVER OLD MEXICO AT 20N98W WHERE THE MOISTURE SEEMS TO EVAPORATE. 
A BROAD UPPER RIDGE DOMINATES THE TROPICS E OF 105W...WITH WEAK 
UPPER DIFFLUENCE ALSO ENHANCING THE CONVECTIVE CLUSTERS NEAR 
05N87W.

A SURFACE HIGH PRESSURE ANALYZED AT 29N121W WILL CONTINUE TO 
SHIFT NE ALLOWING A COLD FRONT TO MOVE INTO THE FAR NW WATERS 
TONIGHT. THE FRONT WILL REACH FROM 32N132W TO 24N140W EARLY FRI 
AS THE POST FRONTAL FLOW INCREASES TO 20 TO 25 KT AND DRIVES 
LARGE NW SWELL INTO THE AREA WITH COMBINED SEAS BUILDING 7 TO 10
FT W OF THE FRONT OVER THE WEEKEND.

$$
NELSON