000
AXPZ20 KNHC 162121
TWDEP 

TROPICAL WEATHER DISCUSSION                                      
NWS NATIONAL HURRICANE CENTER MIAMI FL                           
2205 UTC TUE JUL 16 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 
2100 UTC.

...TROPICAL WAVES...                                     
TROPICAL WAVE EXTENDS ALONG 104W FROM 11N TO 17N MOVING W AT 10 
KT. THE WAVE IS CURRENTLY ACCOMPANIED BY SCATTERED MODERATE TO 
STRONG CONVECTION COVERING THE AREA FROM 10N TO 14N BETWEEN 102W 
AND 106W. CONVECTION IS MORE CONCENTRATED WHERE THE WAVE MEETS 
THE MONSOON TROUGH. THE WAVE IS FORECAST TO GRADUALLY BECOME 
DIFFUSE AS IT TRACKS WESTWARD THROUGH THURSDAY. 

...INTERTROPICAL CONVERGENCE ZONE/MONSOON TROUGH...           
THE MONSOON TROUGH AXIS EXTENDS FROM 08N84W TO 12N105W TO 
11N115W TO 13N122W. THE INTERTROPICAL CONVERGENCE ZONE AXIS 
CONTINUES FROM 13N122W TO 12N130W TO 09N140W. SCATTERED MODERATE 
TO ISOLATED STRONG CONVECTION IS FROM 06N TO 08N BETWEEN 80W AND 
90W. SIMILAR CONVECTION IS ALSO FROM 08N TO 10N BETWEEN 111W AND 
114W. ISOLATED MODERATE TO STRONG CONVECTION IS FROM 07N TO 14N 
BETWEEN 125W AND 129W. SCATTERED MODERATE CONVECTION CAN BE 
FOUND FROM 07N TO 11N BETWEEN 132W AND 136W.

...DISCUSSION...                                               
ALOFT...AN ANTICYCLONE LOCATED WEST OF AREA NEAR 12N145W EXTENDS 
A RIDGE NE ACROSS THE NW WATERS TO ABOUT 28N127W. MODERATE TO 
STRONG SUBSIDENCE AND IMPLIED DRY AIR MASS IS NOTED UNDER THE 
INFLUENCE OF THIS RIDGE PARTICULARLY N OF 15N W OF 125W. TO THE 
EAST...AN UPPER LEVEL LOW IS SPINNING NEAR 22N122W. ANOTHER 
UPPER LEVEL ANTICYCLONIC CIRCULATION IS CENTERED OVER NW MEXICO  
WITH ITS INFLUENCE SPREADING SOUTH AND WEST OVER NORTH-CENTRAL 
MEXICO AND THE BAJA CALIFORNIA PENINSULA. MODERATE TO STRONG SE 
WINDS ARE NOTED BETWEEN THE UPPER LOW AND THIS ANTICYCLONE. AN 
INVERTED TROUGH IS ALSO NOTED ALONG THE SOUTHERN PERIPHERY OF 
THIS ANTICYCLONE...STRETCHING FROM 16N108W TO 10N105W. A THIRD 
ANTICYCLONIC CIRCULATION IS LOCATED OVER NORTHERN CENTRAL 
AMERICA. 

MOST OF THE ACTIVE WEATHER ACROSS THE FORECAST WATERS ARE 
RELATED TO THE MONSOON TROUGH...THE ITCZ AND THE TROPICAL WAVE 
ALONG 104W. TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING 
THE NEXT 48 HOURS. 

AT THE SURFACE...A STRONG HIGH PRES LOCATED WELL NW OF THE 
FORECAST REGION EXTENDS A RIDGE SE ACROSS THE N WATERS TO NEAR 
21N112W. MODERATE TO FRESH TRADE WINDS ARE NOTED PER THE MOST 
RECENT ASCAT PASSES BETWEEN THE SOUTHERN PERIPHERY OF THE RIDGE 
AND THE ITCZ. SEAS OVER THIS AREA RANGE FROM 4 TO 5 FT IN THE  
NW CORNER AND MAXIMIZE IN THE 6 TO 7 FT RANGE FROM 10N TO 20N 
WEST OF 128W ACCORDING TO AN ALTIMETER PASS. THESE OVERALL 
CONDITIONS WILL CHANGE LITTLE OVER THE NEXT 48 HOURS.
   
GAP WINDS OF 15-20 KT WILL PERSIST ACROSS THE GULF OF PAPAGAYO 
THROUGH FRIDAY MORNING AS FRESH TO STRONG TRADE WIND FLOW IN THE 
SW CARIBBEAN FUNNELS TROUGH THE GAP. THE WINDS ARE GREATEST 
DURING THE OVERNIGHT AND EARLY MORNING HOURS WITH THE ASSISTANCE 
OF THE NOCTURNAL DRAINAGE FLOW.

LONG PERIOD CROSS EQUATORIAL SOUTHWESTERLY SWELLS RESULTING IN 
COMBINED SEAS TO 9 FT DOMINATE THE FORECAST WATERS S OF A LINE 
FROM 00N105W TO 04N115W TO 04N122W 00N128W. SWELLS WILL CONTINUE 
TO PROPAGATE NWD DURING THE NEXT 24-48 HOURS WITH ANOTHER SET OF 
LONG PERIOD SW SWELLS...WAVE PERIOD OF 19 TO 21 SECONDS... 
REACHING PARTS OF THE MEXICAN COAST BY WED...AND PARTS OF THE 
COAST OF CENTRAL AMERICA BY THU. 
 
$$ 
GR