000
AXPZ20 KNHC 121558
TWDEP 

TROPICAL WEATHER DISCUSSION      
NWS NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 12 2012

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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1445 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...MONSOON 
TROUGH EXTENDS FROM 09N84W TO 10N96W TO 1008 MB LOW PRES AT 
09N105W TO SECOND LOW PRES AT 10N113W TO 06N120W THEN ITCZ TO 
04N140W.  ISOLATED MODERATE CONVECTION WITHIN 150 NM S OF TROUGH 
FROM 94W TO 100W. 

ALOFT...DEEP LAYERED CYCLONE AT 30N137W WITH UPPER LEVEL TROUGH 
EXTENDING TO 21N140W ASSOCIATED WITH SURFACE LOW PRES 1014 MB AT 
29N138W WITH SURFACE TROUGH EXTENDING TO 25N138W.  VERY DRY 
SUBSIDING AIR MASS ENCROACH INTO BASIN N OF 24N W OF 130W.  WEAK 
DOWNSTREAM MID TO UPPER LEVEL RIDGE WITH AXIS ALONG 120W SUPPORT 
SURFACE 1020 MB HIGH PRES AT 25N128W.  W SIDE OF RIDGE ADVECTS 
MOISTURE ON 60 KT SW JET CORE.  

LONGWAVE TROUGH EXTEND FROM TIP OF BAJA CALIFORNIA TO 10N118W 
ALSO MAINTAINING DRY SLOT BETWEEN ITS AXIS AND RIDGE.  BROAD 
ANTICYCLONE OVER GUATEMALA EXTEND ITS FLOW W ALONG 09N PROVIDING 
MODERATE TO STRONG DIVERGENCE OVER MONSOON TROUGH AXIS E OF 116W.
SEVERAL LOW PRES CENTERS TAKING ADVANTAGE OF FAVORABLE 
ENVIRONMENT ALOFT TO ENHANCE SCATTERED MODERATE TO STRONG 
CONVECTION.  LOW PRES CENTER1009 MB AT 06N112W...PREVIOUSLY 
LABELED 91E...HAS ENTRAINED DRY AIR AND LOST MOST OF ITS 
CONVECTION.  SECOND LOW PRES AT 10N113W IS VERY CLOSE TO DRY 
SLOT AND ONLY HAS ISOLATED TSTMS ASSOCIATED WITH IT.  MAIN 
FEATURE IS 1008 MB LOW PRES AT 10N105W...90E...WHICH CONTINUES 
EMBEDDED IN MONSOON TROUGH BUT STILL HAS LOW LEVEL CIRCULATION 
...SST ABOVE 29 DEGREES AND FAVORABLE UPPER LEVEL ENVIRONMENT TO 
MAINTAIN SCATTERED MODERATE TO STRONG CONVECTION.  MODEL 
GUIDANCE HAVE BECOME MORE IN TUNE WITH DEVELOPMENT THIS FEATURE 
INTO TROPICAL CYCLONE.  PLEASE REFER TO NFDHSFEP2 OR NHCTWOEP 
FOR DETAILS OF FORECAST POSITIONS AND ASSOCIATED CONDITIONS. 

ELSEWHERE AT LOWER LEVELS...
WEAK 1020 MB HIGH PRES REMAINS WELL ANCHORED NEAR 26N128W WITH 
LIGHT TO MODERATE BREEZE AND LOW LEVEL STRATIFIED CLOUDINESS N 
OF 12N W OF 110W.  HIGH PRES CENTER EXPECTED TO DRIFT SE AND 
STRENGTHEN KEEPING AREA WITH LITTLE CHANGE.   

LONG PERIOD SWELLS YIELDING SEAS UP TO 9 FT PRODUCED BY PREVIOUS 
GALE EVENT N OF BASIN EXPECTED TO SUBSIDE BELOW 8 FT LATE SAT. 

WEAK TROUGH EXPECTED TO MOVE OVER YUCATAN PENINSULA FORCING N 
WINDS ACROSS ISTHMUS INTO GULF OF TEHUANTEPEC EARLY SUN.  STRONG 
TO NEAR GALE FORCE N WINDS WITH SEAS TO 10 FT EXPECTED THROUGH 
TUE. 

BUILDING PRES GRADIENT INCREASING E WINDS ACROSS CARIBBEAN SEA 
EXPECTED TO FUNNEL STRONG E WINDS INTO GULF OF PAPAGAYO EARLY 
SUN THROUGH FORECAST PERIOD.

$$
WALLY BARNES