000
AXPZ20 KNHC 050954
TWDEP 

TROPICAL WEATHER DISCUSSION   
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN JUN 05 2011

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0845 UTC.
 
...SPECIAL FEATURE...
.TROPICAL LOW PRES CENTER 1008 MB AT 10N98W HAS FRESH TO STRONG 
WINDS WITHIN 120 NM AROUND N SEMICIRCLE WITH SEAS 6-8 FT. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION WITHIN 120 NM OF 
LINE FROM 13N99W TO 11N96W.  LOW PRES EXPECTED TO DRIFT NW TO 
NEAR 11N100W LATE SUN WITH PRES DROPPING TO 1003 MB BY EARLY 
TUE.  SURFACE WINDS EXPECTED TO INCREASE TO STRONG BREEZE WITHIN 
180 NM AROUND NW AND 240 NM OVER SE SEMICIRCLES WITH POSSIBLE 
TROPICAL CYCLONE FORMATION BY TUE.  

...ITCZ/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 15N93W TO LOW PRES AT 10N98W THEN 
CONTINUE W THROUGH ANOTHER LOW PRES 1010 MB AT 11N115W.  TROUGH 
CONTINUES SW TO 06N123W THEN AS ITCZ TO 06N140W.  SCATTERED 
MODERATE CONVECTION WITHIN 90 AND 150 NM IN NORTHEAST QUADRANT 
OF LOW PRES.   

...DISCUSSION...
DEEP LAYERED CYCLONE JUST N OF E PAC AT 36N126W HAS LARGE 
AMPLITUDE LONGWAVE TROUGH DIG S TO 32N126W THEN TO 08N130W.  
TROUGH SUPPORTS HEALTHY COLD FRONT EXTENDING FROM 32N120W TO 
23N130W TO 24N138W.  TROUGH KEEPS VERY DRY AIR MASS OVER BASIN W 
OF 120W.  DOWNSTREAM RIDGE ANCHORED BY ANTICYCLONIC GYRE AT  
10N115W PROVIDE LOW SHEAR UPPER LEVEL ENVIRONMENT TO WEAK LOW 
PRES 1012 MB AT 11N115W.  IN SPITE OF FAVORABLE ENVIRONMENT 
MODEL GUIDANCE PAYS LITTLE ATTENTION TO THIS FEATURE AND WEAKENS 
IT EVENTUALLY DISSIPATING IT BEYOND FORECAST PERIOD.  

SECOND CYCLONIC VORTEX...THIS ONE OVER  BAY OF CAMPECHE...DIGS 
SW ACROSS SOUTHERN MEXICO INTO E PAC TO ANOTHER VERY ILL-DEFINED 
VORTEX NEAR 12N104W.  UPSTREAM RIDGE SUPPLIES PLENTY OF TROPICAL 
MOISTURE ALOFT FOR VORTEX TO USE ALONG WITH VERY HIGH SEA 
SURFACE TEMPERATURES MAKE MODEL GUIDANCE FAVOR INTENSIFICATION 
OF FEATURE WITHIN 48 HRS.  WEAK STEERING CURRENTS AND 
VARIABILITY IN WIND SHEAR FORECAST ADDS UNCERTAINTY TO FORECAST. 

LASTLY...ANTICYCLONIC GYRE OVER COLOMBIA ADVECTS MORE TROPICAL 
MOISTURE INTO EASTERN SIDE OF BASIN WITH SCATTERED MODERATE 
CONVECTION NOTED E OF 95W.

...AT THE SURFACE...
COLD FRONT EXTENDS FROM 32N120W TO 23N130W TO 24N138W.  WINDS 
HAVE DIMINISHED N OF COLD FRONT BUT NW SWELLS 8-10 FT SPREAD 
INTO E PAC N OF 25N E OF 130W.  PRES GRADIENT EXPECTED TO RELAX 
TODAY WITH FRESH NE TRADES DIMINISHING IN STRENGTH AND COVERAGE 
W OF 134W. 

CROSS EQUATORIAL SWELL WITH SEAS TO 8 FT MOVE INTO WATERS S OF 
10N E OF 125W MON.
 
GAP WINDS...FRESH N BREEZE EXPECTED ACROSS CHIVELA PASS INTO AND 
DOWNWIND OF GULF OF TEHUANTEPEC ASSOCIATED WITH PRES GRADIENT 
CAUSED BY LOW PRES AT 10N98W.  DURATION AND STRENGTH OF EVENT 
HEAVILY DEPENDENT OF INTENSITY AND TRACK OF LOW PRES.  

$$
WALLY BARNES