000
AXPZ20 KNHC 112150
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC THU JUL 11 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2145 UTC.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...   
     
THE MONSOON TROUGH AXIS EXTENDS W FROM THE NW COAST OF COLOMBIA 
AT 11N76W ACROSS COSTA RICA TO THE COAST OF COSTA RICA AT 
11N85W...THEN TURNS NW TO 12N92W...THEN SW TO 11N107W WHERE 
SCATTEROMETER WINDS INDICATE A TRANSITION TO AN INTERTROPICAL 
CONVERGENCE ZONE. THIS ITCZ THEN CONTINUES NW TO 13N115W...THEN 
TURNS ABRUPTLY SW TO 07N130W...THEN WESTWARD TO BEYOND 07N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED S OF 
THE MONSOON TROUGH WITHIN 150 NM EITHER SIDE OF A LINE FROM 
06N82W TO 10N103W ...S OF THE ITCZ WITHIN 15 NM EITHER SIDE OF A 
LINE FROM 08N104W TO 09N110W TO 07N120W. ISOLATED MODERATE TO 
OCCASIONALLY STRONG CONVECTION IS NOTED ELSEWHERE N OF 10N 
BETWEEN 90W AND 99W...AND WELL N OF THE ITCZ WITHIN 90 NM EITHER 
SIDE OF A LINE FROM 13N115W TO 13N130W TO 12N137W...AND ALONG 
THE ITCZ WITHIN 30 NM OF 06N131W.

...DISCUSSION... 

AN UPPER TROUGH EXTENDS SW INTO THE NW PORTION OF THE DISCUSSION 
AREA ALONG 32N128W TO 25N132W. AN INVERTED MID-UPPER TROUGH IS 
FILLING FROM 17N126W TO 21N120W. AN UPPER ANTICYCLONE W OF THE
AREA NEAR 23N147W HAS A RIDGE EXTENDING E TO A CREST AT 21N130W.
THESE THREE UPPER LEVEL SYSTEMS COMBINE TO DRY OUT THE UPPER 
LEVELS OF THE DISCUSSION AREA N OF 18N TO THE W OF 117W.

A BROAD INVERTED UPPER TROUGH...ACCOMPANIED BY DRY AIR ALOFT... 
DOMINATES THE DEEP TROPICS S OF 07N BETWEEN 110W-130W AND IS 
SHIFTING W WITH TIME. THE UPPER FLOW IS SLIGHTLY DIFFLUENT S OF 
THE PREVIOUSLY MENTIONED SUBTROPICAL UPPER RIDGE AND TO THE N OF 
THIS BROAD TROUGH...AND IS ENHANCING THE CONVECTION PREVIOUSLY 
DESCRIBED BETWEEN 115W-140W. THE RESULTANT DEBRIS MOISTURE 
APPEARS THIN...AND IS ADVECTED W ACROSS THE TROPICS FROM 10N-15N 
BETWEEN 115W-140W.

A SMALL UPPER ANTICYCLONE IS CENTERED NEAR 21N114W WITH AN
UPPER RIDGE EXTENDING SE TO 15N104W WITH UPPER MOISTURE TRAPPED 
WITHIN THE RIDGE.  

AN UPPER CYCLONE IS OVER CENTRAL OLD MEXICO AT 22N99W WITH AN
UPPER TROUGH EXTENDING SW TO A BASE NEAR 14N108W. AN UPPER
ANTICYCLONE IS OVER NICARAGUA WITH ITS ENVELOPE OF ANTICYCLONIC
FLOW DOMINATING THE TROPICAL PACIFIC E OF THE JUST DESCRIBED 
UPPER TROUGH. THE ASSOCIATED DIFFLUENCE IS ENHANCING THE 
CONVECTION ACROSS THE WATERS E OF 110W. THE RESULTANT DEBRIS 
MOISTURE FROM THIS CONVECTION HAS MOISTENED THE UPPER LEVELS 
N OF 03N BETWEEN 73W-105W. 

AT THE LOW LEVELS A RIDGE EXTENDS FROM 30N140W TO 15N108W WITH 
NE TRADES AT 15-20 KT ACROSS THE TROPICS FROM 13N-20N W OF 120W 
WITH SEAS OF 5-7 FT IN MIXING NE AND S SWELL.  

SOUTHERLY CROSS EQUATORIAL SWELL IS MAINTAINING COMBINED SEAS OF
6-8 FT ACROSS THE TROPICAL WATERS S OF 08N BETWEEN 108W-118W. 
THESE SWELLS ARE FORECAST TO CONTINUE TO SUBSIDE WITH COMBINED
SEAS BELOW 8 FT BY FRI AFTERNOON.
 
$$ 
NELSON