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Eastern Pacific Tropical Weather Discussion (Text)

000
AXPZ20 KNHC 180320
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC TUE JUN 18 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 
0300 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...            
MONSOON TROUGH AXIS EXTENDS FROM 09N84W TO 08N88W TO 12N100W TO 
TO 1009 MB LOW 11N104W TO 09N110W TO 11N118W. ITCZ AXIS 
CONTINUES FROM 11N118 TO 10N127W TO BEYOND 08N140W. SCATTERED 
MODERATE/ISOLATED STRONG CONVECTION EXISTS FROM 11N TO 13N 
BETWEEN 104W AND 106W. SIMILAR CONVECTION IS ALSO FROM 10N TO 
13N BETWEEN 121W AND 129W.

...DISCUSSION...                                                
ALOFT...SW TO W FLOW IS EVIDENT ACROSS THE NORTH WATERS MAINLY N 
OF 22N AHEAD OF AN UPPER TROUGH THAT STRETCHES FROM A LARGE 
CYCLONE VORTEX WELL N OF THE AREA SWWD TO THE CENTRAL TROPICAL 
PACIFIC REGION. MODERATE TO STRONG SUBSIDENCE PREVAILS ACROSS 
THIS PORTION OF THE AREA LEADING TO RATHER DRY AND STABLE 
ATMOSPHERIC CONDITIONS. THE ANTICYCLONE THAT WAS LOCATED 
YESTERDAY NEAR THE SOUTHERN TIP OF BAJA CALIFORNIA HAS MIGRATED 
SW AND NOW IS CENTERED NEAR 19N119W WITH AN ASSOCIATED RIDGE 
EXTENDING SEWD TO NEAR 05N105W. UPPER DIFFLUENCE ALONG THE 
SOUTHERN PERIPHERY OF THIS RIDGE CONTINUES TO ENHANCE CONVECTION 
NEAR THE MONSOON TROUGH/ITCZ AXIS AS DESCRIBED ABOVE. ANOTHER 
RIDGE EXTENDS NEWD FROM THE AFOREMENTIONED ANTICYCLONE ACROSS 
SOUTHERN BAJA CALIFORNIA AND NORTHERN MEXICO INTO THE WESTERN 
GULF OF MEXICO. AN UPPER LOW IS IDENTIFIED NEAR 12N98W WITH A 
TROUGH EXTENDING NWD ACROSS THE BAY OF CAMPECHE INTO THE CENTRAL 
GULF OF MEXICO. ELY FLOW ALOFT ON THE SOUTH SIDE OF AN UPPER 
ANTICYCLONE OVER THE CARIBBEAN SEA IS ADVECTING MID TO UPPER 
LEVEL MOISTURE ACROSS THE FAR EASTERN PORTION OF THE AREA N OF 
05N AND E OF ABOUT 90W. 

A DIFFLUENT PATTERN ALOFT BETWEEN THE ANTICYCLONE NEAR 19N119W 
AND AN INVERTED UPPER TROUGH TO ITS SOUTH IS HELPING TO INDUCE 
THE AREA OF MODERATE TO ISOLATED STRONG CONVECTION THAT COVERS 
FROM 10N TO 13N BETWEEN 121W AND 129W. 

ELSEWHERE AT THE SURFACE...HIGH PRES LOCATED NEAR 32N137W 
EXTENDS A RIDGE SE ACROSS THE N WATERS TO NEAR 20N115W. THE HIGH 
PRES IS FORECAST TO GRADUALLY DISSIPATE OVER THE NEXT 12-24 HRS 
AND BE REPLACED BY STRONGER HIGH PRES THAT BUILDS EWD JUST TO 
THE N OF THE FORECAST REGION THROUGH WED. AS THIS HIGH PRES 
BUILDS EWD...THE RESULTING PRES GRADIENT BETWEEN IT AND 
GENERALLY LOWER PRES OVER THE WRN U.S. W COAST WILL SUPPORT 
FRESH TO STRONG WINDS NEAR THE COAST OF CALIFORNIA. NW TO N 
SWELLS GENERATED BY THESE WINDS ARE EXPECTED TO INVADE THE NE 
WATERS LATER TONIGHT AND LAST INTO WED NIGHT. THE FORECAST CALLS 
FOR INCREASING WINDS TO 20-25 KT AND BUILDING SEAS OF UP TO 10 
FT BY TUE NIGHT OVER THE AREA N OF 28N BETWEEN 116W AND 122W

THE MOST RECENT SCATTEROMETER DATA SHOW THAT NE TRADES OF 20-25 
KT ARE PRESENT S OF THE AFOREMENTIONED RIDGE FROM 11N TO 19N W 
OF 125W WITH SEAS TO 9 FT. EXPECT LITTLE CHANGE TO THESE MARINE 
CONDITIONS OVER THE NEXT 48 HRS. 

AN EARLIER ASCAT PASS SHOWED NLY WINDS OF 20-25 KT ACROSS THE 
GULF OF TEHUANTEPEC LIKELY IN ASSOCIATION WITH THE CIRCULATION 
OF TROPICAL DEPRESSION TWO THAT FORMED OVER THE GULF OF HONDURAS 
MON MORNING. IN ADDITION...SALINA CRUZ IN THE STATE OF OAXACA 
REPORTED N WINDS UP TO 24 KT MON AFTERNOON. BASED ON THE 
OFFICIAL FORECAST TRACK...THAT MOVES THE CENTER OF TROPICAL 
DEPRESSION TWO OVER BELIZE AND NORTHERN GUATEMALA TONIGHT AND 
EARLY TUESDAY...OVER EASTERN MEXICO LATER ON TUESDAY AND ACROSS 
THE SOUTHERN BAY OF CAMPECHE BY EARLY WEDNESDAY...DECIDE TO KEEP 
THE NLY WINDS OF 20-25 KT ACROSS THE GULF OF TEHUANTEPEC THROUGH 
48 HOURS. HOWEVER...THIS FORECAST IS HIGHLY DEPENDENT OF THE 
TRACK AND INTENSITY OF CURRENT T.D. TWO.

ADDITIONAL PULSES OF CROSS EQUATORIAL SW SWELLS ARE PROPAGATING 
THROUGH THE SOUTH-CENTRAL WATERS...RAISING SEAS TO 8 FT S OF 03N 
BETWEEN 116W AND 127W. THESE SWELLS ARE FORECAST BY WAVEWATCH 
GUIDANCES TO REACH THE COASTLINES OF CENTRAL AMERICA AND MEXICO 
THROUGH WED AS THEY WILL BE REINFORCED BY YET ANOTHER BATCH OF 
LONG PERIOD SW SWELLS WITH PERIODS OF 18-20 SEC. THESE SWELLS 
COULD LEAD TO ROUGH SURF NEAR AND ALONG THE ABOVE COASTLINES. 

$$ 
GR