000
AXPZ20 KNHC 140945
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC FRI MAY 14 2010

TROPICAL WEATHER DISCUSSION FOR THE EASTERN PACIFIC OCEAN FROM 
THE EQUATOR TO 32N...EAST OF 140W. 

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0900 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 88W FROM 03N TO 08N MOVING W AT 10 
KT. THE WAVE COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE 
WATER IMAGERY. CONVECTION ASSOCIATED WITH THE WAVE HAS RAPIDLY 
DISSIPATED DURING THE PAST SEVERAL HOURS AS IT IS ENCOUNTERING 
INCREASING SHEAR ALOFT. ONLY A FEW SHOWERS ARE NOTED EITHER SIDE 
OF THE WAVE AXIS.

...ITCZ...

THE ITCZ AXIS IS ALONG 07N78W TO 07N90W TO 08N102W TO 08N120W TO 
07N140W. SCATTERED MODERATE TO ISOLATED STRONG CONVECTION IS 
NOTED ALONG THE COAST OF COLOMBIA N OF 02N. SCATTERED MODERATE 
CONVECTION IS FROM 06N TO 11N BETWEEN 107W AND 112W. SIMILAR 
CONVECTION IS WITHIN 60 NM N OF AXIS W OF 137W. 

...DISCUSSION...

ALOFT...A DEEP LAYER TROUGH EXTENDS ACROSS THE N WATERS FROM THE 
SW U.S. TO 24N125W TO 23N140W. MODERATE TO STRONG SUBSIDENCE IS 
NOTED ALONG AND AHEAD OF THE TROUGH...WHILE UPPER LEVEL MOISTURE 
IS SURGING S INTO THE AREA BEHIND THE TROUGH MAINLY N OF 26N.  

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 10N106W WITH A BROAD 
RIDGE EXTENDING EWD TO NEAR 87W. THIS RIDGE ALSO DOMINATES SE 
MEXICO AND NORTHERN CENTRAL AMERICA. A JETSTREAM BRANCH WITH 
CORE WIND SPEEDS OF 90-110 KT LIES BETWEEN THE AFOREMENTIONED 
TROUGH AND THIS ANTICYCLONE ENTERING THE FORECAST NEAR 16N140W 
AND CONTINUING E-NE ACROSS SOUTHERN BAJA PENINSULA INTO MAINLAND 
MEXICO. THE RIDGE IS HELPING TO INDUCE CONVECTION ALONG THE 
ITCZ. A DIFFLUENT PATTERN ALOFT IS ENHANCING CONVECTION ALONG 
THE PACIFIC COST OF COLOMBIA AND PANAMA.

AT THE SURFACE...A HIGH PRES CENTER NEAR 32N139W EXTENDS A RIDGE 
ACROSS THE DISCUSSION AREA TO 18N117W. BOTH A RECENT ASCAT PASS 
AND AN EARLIER WINDSAT PASS SHOWED NE TRADES AT 20 TO 25 KT ON 
THE SOUTHERN PERIPHERY OF THE RIDGE COVERING A LARGE AREA FROM 
09N TO 24N W OF 124W. THE AERIAL EXTENT AND STRENGTH OF THE 
TRADES WILL DECREASE DURING THE NEXT 48 HOURS AS THE HIGH AND 
RIDGE WEAKEN. PRES GRADIENT BETWEEN THE HIGH AND LOWER PRES OVER 
THE SW CONUS IS ALSO PRODUCING AN AREA OF NORTHERLY WINDS OF 20 
KT N OF 28N BETWEEN 120W AND 128W. THESE WINDS SHOULD DIMINISH 
TO LESS THAN 20 KT WITHIN THE NEXT 24 HOURS AS THE PRES GRADIENT 
IN THAT AREA WEAKENS. A PAIR OF WEAK TROUGHS ARE SEEN EMBEDDED 
WITHIN THE ITCZ. ONE IS ALONG 103W/104W AND THE OTHER IS ALONG 
129W. CONVECTION HAS SLIGHTLY INCREASED NEAR THE EASTERNMOST 
TROUGH. THE GFS COMPUTER MODEL SUGGESTS THAT A COLD FRONT 
WILL REACH THE FAR NW CORNER OF THE AREA BY SUN.  

THE REGIONAL SEAS ARE DOMINATED BY NE WIND WAVES DUE TO THE 
TRADE WINDS AND LONG PERIOD...16-18 SECONDS...CROSS EQUATORIAL 
SW SWELLS. THESE SWELLS WILL GRADUALLY DECAY TO LESS THAN 8 FT 
OVER THE MAJORITY OF THE DISCUSSION AREA DURING THE NEXT 48 
HOURS.

GAP WINDS...NE TO E WINDS AT 20 KT ARE SURGING THROUGH THE GULF 
OF PAPAGAYO DOWNWIND TO 90W. THESE WINDS ARE EXPECTED TO 
DIMINISH TO LESS THAN 20 KT WITHIN THE NEXT 36-48 HOURS.

$$
GR