000
AXPZ20 KNHC 200228 CCA
TWDEP 

TROPICAL WEATHER DISCUSSION...CORRECTED 
NWS NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC WED JUN 20 2012

CORRECTED SATELLITE VALID TIME 

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 
0215 UTC.

...SPECIAL FEATURES...
THE LAST VISIBLE SATELLITE IMAGE SHOWED THAT THE LOW LEVEL 
CIRCULATION ASSOCIATED WITH THE LOW PRES NEAR 18N107W REMAINS 
EXPOSED DUE TO MODERATE NE WIND VERTICAL SHEAR ALOFT. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 90 NM OF THE LOW 
IN THE SW QUADRANT. THE LOW REMAINS EMBEDDED IN THE NE PORTION 
OF THE MONSOON TROUGH...WITH STRONG SW TO S WINDS CONTINUING 
ACROSS A BROAD AREA SE OF THE LOW AND THE MONSOON TROUGH. 
UPPER-LEVEL WINDS REMAIN MARGINALLY CONDUCIVE FOR DEVELOPMENT.
SATELLITE IMAGERY OVER THE PAST FEW HOURS REVEALED THAT 
CONVECTION DIRECTLY ASSOCIATED WITH THE LOW HAS DIMINISHED BOTH
IN AREAL AND INTENSITY COVERAGE. THIS SYSTEM NOW HAS A MEDIUM
CHANCE OF BECOMING A TROPICAL CYCLONE DURING THE NEXT 48 HOURS 
AS IT REMAINS NEARLY STATIONARY. DEEP TROPICAL MOISTURE MOSTLY
ASSOCIATED WITH THE MONSOON TROUGH TO THE SE OF THE LOW IS BEING 
ADVECTED ENE TOWARDS SRN MEXICO. THIS MOSITURE WILL CONTINUE TO
BRING LOCALLY HEAVY RAINFALL PRIMARILY ALONG THE SOUTHERN COAST 
OF MEXICO DURING THE NEXT 48 HRS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...
MONSOON TROUGH EXTENDS FROM 15N105W TO THE 1005 MB LOW AT 
18N107W...AND SW TO 11N118W TO 10N125W. THE ITCZ AXIS EXTENDS 
FROM 10N125W TO 07N131W AND TO BEYOND 05N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 60-75 NM SE OF 
THE MONSOON TROUGH. SCATTERED MODERATE CONVECTION IS WITHIN 
60 NM S OF THE ITCZ.

...DISCUSSION...
A MID TO UPPER LEVEL CUT OFF LOW MOVING NNW IS NEAR 28.5N135W. 
AN INVERTED TROUGH...REFLECTION OF THIS LOW...IS ANALYZED AT THE 
SURFACE EXTENDING FROM 30N132W SW TO 21N140W. UPPER RIDGING 
GENERALLY PREVAILS BETWEEN THIS LOW AND NW MEXICO...INCLUDING 
THE BAJA CALIFORNIA PENINSULA. THE RIDGE IS ANCHORED ON AN  
ANTICYCLONIC CIRCULATION LOCATED NEAR 24N118W. UPPER DIFFLUENCE 
ON THE SE AND S PARTS OF THIS SYSTEM IS CONTINUING TO INDUCE 
CONVECTION NEAR THE LOW PRES AT 18N107W AND ALONG THE MONSOON 
TROUGH. THE RIDGE ALSO EXTENDS SE ALONG THE MEXICAN COAST. UPPER 
LEVEL NE WINDS PREVAIL E OF 100W. WATER VAPOR IMAGERY SHOWS 
ABUNDANT SUBSIDENCE MAINTAIN RATHER DRY AND STABLE ATMOSPHERIC 
CONDITIONS OVER MUCH OF THE AREA TO THE NW OF MONSOON TROUGH 
ASSOCIATED MOISTURE AND CONVECTION DESCRIBED ABOVE.

ELSEWHERE AT THE SURFACE...A RIDGE EXTENDS INTO THE AREA TO THE 
E OF THE ABOVE SURFACE TROUGH FROM 32N133W AND TO NEAR 24N122W. 
A VERY TIGHT PRES GRADIENT CONTINUES BETWEEN THE SURFACE TROUGH 
MENTIONED ABOVE AND THE RIDGE ALLOWING FOR FRESH TO STRONG NELY 
WINDS ACROSS THE NW PORTION OF THE DISCUSSION AREA REA...MAINLY
N OF 25N TO THE NW OF THE TROUGH AXIS WITH SEAS OF 8 TO 11 FT. 
GLOBAL MODELS INDICATE THAT THE TROUGH WILL DRIFT WWD AND 
GRADUALLY WEAKEN AS THE RIDGE STRENGTHENS...RESULTING IN A 
GRADUAL DECREASE IN WINDS AND SEAS ACROSS THE NW WATERS OVER THE 
NEXT 48 HOURS.

AS MENTIONED ABOVE...SW WINDS OF 20 TO 25 KT ARE NOTED IN A 
LARGE AREA SE OF LOW PRES CENTER NEAR 18N107W...AND ALONG AND SE 
OF THE MONSOON TROUGH THERE...COVERING ROUGHLY FROM 14N TO 17N 
BETWEEN 102W AND 110W. THE SW FLOW EXTENDS FARTHER E AND BECOMES 
WLY ALONG THE PACIFIC COAST OF MEXICO TO OFFSHORE OF THE GULF OF 
TEHUANTEPEC. THIS FLOW IS CONTINUES TO PUMP ABUNDANT TROPICAL 
MOISTURE ACROSS THESE AREAS...RESULTING IN SCATTERED TO NUMEROUS 
SHOWERS AND TSTMS WITH PERIODS OF LOCALLY HEAVY RAINFALL AS 
WELL. THIS PATTERN IS EXPECTED TO REMAIN IN PLACE FOR THE NEXT 
FEW DAYS...AND WILL MAINTAIN A WET WEATHER PATTERN ACROSS MOSTLY 
THE NRN PART OF CENTRAL AMERICA AND SOUTHERN MEXICO.

$$
AGUIRRE