000
AXPZ20 KNHC 240951
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
1005 UTC MON JUN 24 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...

TROPICAL STORM COSME AT 12.8N 105.2W 1003 MB AT 0900 UTC JUN 24 
MOVING NW OR 305 DEGREES AT 9 KT. MAXIMUM SUSTAINED WINDS ARE 35 
KT WITH GUSTS TO 45 KT. NUMEROUS MODERATE TO STRONG CONVECTION 
IS OBSERVED WITHIN 420 NM OVER THE SW QUADRANT WITH BANDING 
FEATURES. SCATTERED MODERATE ISOLATED STRONG CONVECTION IS NOTED 
WITHIN 360 NM OVER THE E SEMICIRCLE AND WITHIN 180 NM OVER THE 
NW QUADRANT. COSME IS FORECAST TO BRIEFLY BECOME A HURRICANE ON 
TUE NIGHT THEN WEAKEN TO A TROPICAL STORM ON WED NIGHT AS IT 
CONTINUES NW OVER COOLER SURFACE WATERS. 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 WNW FROM THE BORDER OF COLOMBIA 
AND PANAMA TO THE PACIFIC COAST OF COSTA RICA AT 10N86W...THEN 
CONTINUES W TO 10N90W THEN NW TO 12N100W WHERE THE TROUGH LOSES 
IDENTITY IN BROAD CYCLONIC CIRCULATION ASSOCIATED WITH THE 
DEVELOPING TROPICAL CYCLONE COSME. THE MONSOON TROUGH RESUMES W 
OF COSME NEAR 13N110W AND CONTINUES SW THROUGH AN EMBEDDED 1008 
MB LOW PRESSURE AT 13N114W TO 11N127W WHERE SCATTEROMETER WINDS 
INDICATE A TRANSITION TO AN INTERTROPICAL CONVERGENCE ZONE. THE 
ITCZ AXIS CONTINUES W TO BEYOND 09N140W. SCATTERED MODERATE TO 
STRONG CONVECTION IS FLARING WITHIN 240 NM OVER THE SW QUADRANT 
OF AN EMBEDDED SURFACE LOW AT 13N114W WHILE SCATTERED MODERATE 
ISOLATED STRONG IS NOTED OVER THE SE QUADRANT WITHIN 30 NM OF 
12.5N 112.5W. ELSEWHERE EXCEPT AS NOTED NEAR COSME...SCATTERED 
MODERATE ISOLATED STRONG CONVECTION IS NOTED WITHIN 90 NM OF 
06N78W...AND WITHIN 90 NM EITHER SIDE OF A LINE FROM 06N83W TO 
12N102W...WITHIN 75 NM EITHER SIDE OF A LINE FROM 09N104W TO 
10N111W...WITHIN 90 NM EITHER SIDE OF A LINE FROM 10N121W TO 
08N135W..AND WITHIN 75 NM OF 07N140W. 

SCATTERED MODERATE ISOLATED STRONG CONVECTION IS OBSERVED 
RUNNING PARALLEL TO COAST OF CENTRAL AMERICA WITHIN 60 NM EITHER 
SIDE OF A LINE FROM 11N90W TO 15N96W AND WITHIN 90 NM EITHER 
SIDE OF A LINE FROM 11.5N95W TO 18N105W.

...DISCUSSION... 

THE 1008 MB LOW PRESSURE NEAR 13N114W IS EXPECTED TO LOSE 
IDENTITY WITHIN THE MONSOON TROUGH TODAY AS TROPICAL STORM COSME 
INTENSIFIES.

AN UPPER TROUGH HAS SWUNG SE ACROSS SOUTHERN CALIFORNIA TRAILING
AN UPPER TROUGH SW FROM 30N118W TO 28N140W. THIN UPPER MOISTURE 
IS SPREADING S ACROSS THE DISCUSSION AREA N OF THIS TROUGH. A 
WEAK SURFACE COLD FRONT WILL MOVE INTO THE NW PORTION OF THE 
DISCUSSION AREA ON TUE NIGHT AND DISSIPATE ON WED. A SECOND COLD 
FRONT WILL APPROACH THE FAR NW PORTION IN THU. BOTH OF THESE  
FRONTS WILL BE ONLY BE ACCOMPNAIED BY A 10-15 KT SW-W-NW WIND 
SHIFT AND NW SWELLS RESULTING IN COMBINED SEAS TO 8 FT. 

A SMALL UPPER LEVEL CYCLONE IS QUASI-STATIONARY AT 20N108W WITH 
AN UPPER TROUGH EXTENDING WSW THROUGH 16N121W AND INTO ANOTHER 
UPPER CYCLONE OVER THE TROPICS AT 15N126W. AN UPPER CYCLONE 
FORMALLY ALONG THIS TROUGH HAS CUT OFF AT 15N138W. AN UPPER 
RIDGE IS NOW EXTENDING E INTO THE AREA ALONG 19N TO THE E OF 
135W. A MOISTURE PLUME IS NOTED N OF THIS RIDGE WITHIN 150 NM OF 
A LINE FROM 23N140W TO 26N127W. 

AN UPPER ANTICYCLONE IS CENTERED AT 23N118W WITH AN UPPER RIDGE
EXTENDING W TO A CREST AT 22N124W. THIS UPPER RIDGE WILL PROVIDE
THE STEERING FOR TROPICAL CYCLONE COSME FOR THE NEXT COUPLE OF DAYS. 

AN UPPER ANTICYCLONE IS ESTIMATED NEAR 15N100W WITH ITS ENVELOPE
OF ANTICYCLONIC FLOW DOMINATING THE UPPER LEVELS BETWEEN 88W-109W
WHERE DENSE UPPER MOISTURE IS OBSERVED. THIS IS PROVIDING THE 
UPPER DIFFLUENCE OVER DEVELOPING TROPICAL CYCLONE COSME...AND 
FOR THE CONVECTION PREVIOUSLY DESCRIBED TO THE E OF 110W.

A SURFACE RIDGE EXTENDS FROM 28N140W TO 21N11W. NW WINDS AT 10-15
KT ARE OCCURRING E OF THE RIDGE WITHIN 240 NM OF THE BAJA PENINSULA 
WITH SEAS 4-6 FT IN NW SWELL. LITTLE CHANGE EXPECTED THROUGH
LATE TUE. CROSS EQUATORIAL S SWELL...RESULTING IN COMBINED SEAS TO
10 FT...HAS PROPAGATED NE TO ALONG 10N BETWEEN 100W-130W. THESE
SOUTHERLY SWELLS WILL MIX WITH THE SWELLS GENERATED BY TROPICAL 
CYCLONE COSME BEGINNING TODAY. THE SOUTHERLY SWELL COMPONENT 
WILL REACH THE COAST OF CENTRAL AMERICA BETWEEN 97W-105W THIS 
AFTERNOON...AND CONTINUE TO BE REINFORCED BY THE CYCLONE WITH 
THE COMBINED S SWELL MOVING INTO THE SOUTHERN GULF OF CALIFORNIA 
ON TUE NIGHT...AND PROPAGATING N ALONG THE WESTERN SHORE OF THE 
BAJA PENINSULA ON WED REACHING ALONG 30N ON WED NIGHT. 
 
$$ 
NELSON