Eastern Pacific Tropical Weather Discussion

000
AXPZ20 KNHC 200257
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
0405 UTC THU JUN 20 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 10N86W TO 11N95W TO 09N101W TO 1007 MB LOW PRES 
NEAR 10N110W TO 10N125W. ITCZ CONTINUES FROM 10N125W TO 11N130W 
TO 10N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION 
WITHIN 120 NM S OF THE MONSOON TROUGH E OF 100W. SCATTERED 
MODERATE ISOLATED STRONG CONVECTION FROM 09N TO 12N BETWEEN 105W 
AND 115W.

...DISCUSSION... 

AN UPPER TROUGH EXTENDS FROM AN UPPER CYCLONE CENTERED NEAR 
16N112W TO 15N100W. THIS IS SUPPORTING A 1007 MB SURFACE LOW 
PRES AREA NEAR 10N110W ALONG THE MONSOON TROUGH. E OF THE 
LOW...SCATTEROMETER DATA INDICATE A SURGE OF MODERATE TO FRESH 
SW FLOW INTO THE MONSOON TROUGH. THIS IS SUPPORTING CLUSTERS OF 
MODERATE TO STRONG CONVECTION WITHIN 120 NM S OF THE MONSOON 
TROUGH E OF 100W. RECENT CRYOSAT DATA ALSO INDICATE SEAS TO 8 FT 
IN THIS AREA.

FRESH N FLOW WAS NOTED IN THE GULF OF TEHUANTEPEC SEVERAL HOURS 
AGO RELATED TO BROAD SCALE FLOW AHEAD OF THE DEVELOPING T.S. 
BARRY IN THE SW GULF OF MEXICO. BARRY HAS SINCE SHIFTED FARTHER 
W TOWARD VERACRUZ...ALLOWING WINDS TEHUANTEPEC AREA TO DIMINISH 
AND SHIFT MORE SOUTHERLY. T.S. BARRY IS FORECAST TO MOVE ACROSS 
THE FAR SE GULF OF MEXICO...MAKING LANDFALL TOMORROW MORNING AND 
DISSIPATING OVER CENTRAL MEXICO BY FRI. NO MAJOR IMPACT IS 
ANTICIPATED TO THE PACFIC WATERS...BUT HEAVY RAINFALL IS LIKELY 
OVER S CENTRAL MEXICO THROUGH FRI.

THROUGH THE NEXT 48 TO 72 HOURS...OPERATIONAL MODELS ARE IN 
REASONABLE AGREEMENT INDICATING THE LOW NEAR 10N110W WILL DRIFT 
SLOWLY W. MEANWHILE...A SECOND SURFACE LOW WILL FORM NEAR 
12N100W THROUGH SAT UNDER THE INFLUENCE OF THE QUASI-STATIONARY 
UPPER TROUGH. AN ASCAT PASS FROM 1545 UTC INDICATED SOME HINT OF 
THIS POSSIBLY ALREADY STARTING TO FORM ALONG THE MONSOON TROUGH. 

FARTHER WEST...BROAD TROUGH IS EVIDENT IN THE LOWER LEVELS OF 
THE ATMOSPHERE ALONG 130W AS NOTED IN GOES DERIVED WIND FIELDS. 
THE SURFACE WINDS INDICATE THAT THERE IS A KINK IN THE ITCZ IN 
THIS AREA. SCATTEROMETER AND ALTIMETER DATA FROM THE PAST 12 
HOURS ALSO INDICATES POCKETS OF 20 TO 25 KT WINDS IN THE 
GRADIENT BETWEEN THE INCIPIENT TROUGH AND HIGH PRES N OF THE 
AREA WITH SEAS TO 9 FT. GLOBAL MODELS INDICATE THE TROUGH WILL 
MIGRATE W OF 140W THROUGH LATE FRI.

A SURFACE RIDGE EXTENDS FROM 35N145W TO SOUTH OF THE BAJA 
PENINSULA. SHIP OBSERVATIONS AND ASCAT DATA INDICATE FRESH NW TO 
N WINDS BETWEEN THE HIGH PRES AND THE COAST OF BAJA...MAINLY N 
OF 23N E OF 125W. 

$$ 
CHRISTENSEN