000
AXPZ20 KNHC 260948
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC WED JUN 26 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0945 UTC.

...SPECIAL FEATURES...

HURRICANE COSME AT 18.4N 114.5W 981 MB AT 0900 UTC JUN 26 MOVING 
WNW OR 290 DEGREES AT 12 KT. MAXIMUM SUSTAINED WINDS ARE 70 KT 
WITH GUSTS TO 85 KT. NUMEROUS STRONG CONVECTION IS OBSERVED 
WITHIN 90 NM OVER THE SE SEMICIRCLE. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS NOTED ELSEWHERE WITHIN 150 NM EITHER SIDE 
OF A LINE FROM 22N116W TO 17N113W TO 14N114W. COSME IS FORECAST 
TO MAINTAIN HURRICANE STRENGTH THROUGH THIS MORNING...THEN WILL 
WEAKEN TO A TROPICAL STORM THIS AFTERNOON AS IT MOVES OVER 
COOLER SEA SURFACE TEMPERATURES. COSME IS FORECAST TO WEAKEN TO 
TROPICAL REMNANT LOW PRESSURE SAT NIGHT. SEE THE LATEST 
FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMEP3/WTNT23 KNHC 
FOR MORE DETAILS.

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH... 
           
THE MONSOON TROUGH AXIS EXTENDS W FROM COLOMBIA AT 08N76W TO 
ACROSS THE PANAMA TO THE COAST OF COSTA RICA AT 08N85W TO 07N97W 
THEN TURNS WNW TO 11N105W WHERE THE TROUGH LOSES IDENTITY IN 
BROAD CYCLONIC CIRCULATION ASSOCIATED WITH TROPICAL CYCLONE 
COSME. THE MONSOON TROUGH RESUMES WELL SW OF COSME NEAR 12N118W 
AND CONTINUES WSW TO BEYOND 08N140W. SCATTERED MODERATE ISOLATED 
STRONG CONVECTION IS OBSERVED WITHIN 150 NM OF 09N98W AND 
11N107W. ISOLATED MODERATE TO OCCASIONALLY STRONG CONVECTION IS 
NOTED ALONG THE WESTERN SEGMENT OF THE MONSOON TROUGH...ROUGHLY 
WITHIN 30 NM EITHER SIDE OF A LINES FROM 10N117W TO 
08N122W AND FROM 08N133W TO 07N140W.

SCATTERED MODERATE ISOLATED STRONG CONVECTION CONTINUES TO FLARE
WITHIN 150 NM OF COAST OF MEXICO FROM 88W TO 106W.

...DISCUSSION... 

AN UPPER CYCLONE HAS CUT OF AT 29N129W WITH AN UPPER TROUGH
EXTENDING SW INTO ANOTHER UPPER CYCLONE AT 19N142W. A 180 NM
WIDE BAND OF THIN UPPER MOISTURE IS INDICATED WITHIN 150 NM 
N OF THE UPPER TROUGH. A COLD FRONT IS WEAKENING FROM 32N133W
TO 29N140W AND IS ONLY ACCOMPANIED BY ONLY A 5-10 KT SW-W WIND
SHIFT...BUT SEAS OF 6-8 FT ARE OBSERVED N OF THE BOUNDARY 
PRIMARILY DUE TO NW SWELL. THIS BOUNDARY SHOULD LOSE IDENTITY
TONIGHT WITH THE AREA OF ASSOCIATED SEAS OF 8 FT OR GREATER
SHIFTING NE OF THE AREA ON THU MORNING.  

AN UPPER ANTICYCLONE IS OVER THE SOUTHERN GULF OF CALIFORNIA
WITH ITS ENVELOPE OF ANTICYCLONIC FLOW DOMINATING THE UPPER
LEVELS 95W-111W PROVIDING THE UPPER DIFFLUENCE OVER TROPICAL 
CYCLONE COSME...AND FOR THE OTHER CONVECTION PREVIOUSLY DESCRIBED 
BETWEEN 95W-115W. THIS CONVECTION CONTINUES TO CONTRIBUTE TO 
EXTREMELY DENSE UPPER MOISTURE TRAPPED WITHIN THE ANTICYCLONIC 
ENVELOPE. THIS MID/UPPER RIDGE WILL PROVIDE THE STEERING FOR 
TROPICAL CYCLONE COSME AS IT WEAKENS OVER THE NEXT COUPLE OF DAYS. 

A SURFACE RIDGE EXTENDS FROM 25N140W TO 27N117W. CROSS EQUATORIAL 
SOUTHERLY SWELL CONTINUES TO PROPAGATE N ACROSS THE DISCUSSION AREA
BETWEEN 99W-130W AND IS REINFORCED BY SWELL GENERATED BY TROPICAL
CYCLONE COSME. THESE SOUTHERLY SWELLS ARE REACHING THE PACIFIC
COAST OF MEXICO FROM 17N-25N...INCLUDING THE GULF OF CALIFORNIA
S OF 25N. THESE SWELLS WILL CONTINUE PROPAGATE N ALONG THE 
WESTERN SHORE OF THE BAJA PENINSULA REACHING ALONG 30N LATE
TONIGHT. THE SWELL WILL SUBSIDE TO LESS THAN 8 FT ACROSS THE
WATERS E OF 112W ON THU NIGHT.
 
$$ 
NELSON