000
AXPZ20 KNHC 140251
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC FRI MAY 14 2010

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

BASED ON 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
0300 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 87W FROM 02N TO 08N MOVING W AT 10 
KT. THE WAVE COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE 
WATER IMAGERY AND IN A POTENTIAL VORTICITY MAXIMUM WHICH CAN BE 
TRACKED BACK SEVERAL DAYS TO THE ATLANTIC OCEAN. CONVECTION 
ASSOCIATED WITH THE WAVE HAS RAPIDLY DISSIPATED DURING THE PAST 
6 HOURS AS IT IS ENCOUNTERING INCREASING SHEAR ALOFT.

...ITCZ...

AXIS ALONG 05N77W TO 06N86W TO 07N102W TO 08N113W TO 06N138W. 
SCATTERED MODERATE CONVECTION WITHIN 90 NM N OF THE AXIS BETWEEN 
95W AND 98W AND WITHIN 120 NM N OF THE AXIS BETWEEN 110W AND 
115W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM 32N115W TO 25N120W TO 16N140W 
WITH DRY AIR IN PLACE WITHIN 300 NM W-NW OF THE TROUGH AXIS DUE 
TO STRONG CONFLUENT WINDS. MEANWHILE UPPER LEVEL MOISTURE IS 
DIGGING TO THE SE-S BEHIND THE TROUGH N OF 24N. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 09N108W WITH A BROAD 
RIDGE EXTENDING ALONG 09N BETWEEN 88W AND 137W. A JETSTREAM WITH
PEAK UPPER LEVEL CORE WIND SPEEDS OF 90-110 KT IS ADVECTING 
CONVECTIVE ITCZ DEBRIS TO THE NE-E AROUND THE NORTHERN PERIPHERY 
OF THE RIDGE INTO CENTRAL MEXICO. THE RIDGE IS ALSO PROVIDING 
LITTLE SHEAR ALONG WITH AMPLE OUTFLOW AIDING IN THE DEVELOPMENT 
OF ITCZ CONVECTION THROUGHOUT THE MAJORITY OF THE DISCUSSION 
AREA. 

A WEAK DEFORMATION ZONE BETWEEN THE RIDGE AND ANOTHER RIDGE 
EXTENDING FROM NORTHERN COLOMBIA TO 06N88W IS BRINGING DRY AIR S 
FROM CENTRAL AMERICA NW OF COSTA RICA WHICH IS INTERRUPTING THE 
ITCZ CONVECTIVE BELT BETWEEN 88W AND 95W. MEANWHILE UPPER LEVEL 
DIFFLUENCE UNDER THE COLOMBIAN RIDGE IS ENHANCING CONVECTION 
OVER COSTA RICA AND PANAMA.

AT THE SURFACE...A BROAD RIDGE STEMS FROM 1029 MB HIGH PRES 
CENTERED NEAR 32N139W AND EXTENDS ACROSS THE DISCUSSION AREA TO 
14N107W. NE TRADES AT 20 TO 25 KT ARE SW OF THE RIDGE AXIS FROM 
09N TO 25N W OF 124W. THE AERIAL EXTENT AND STRENGTH OF THE 
TRADES WILL DECREASE DURING THE NEXT 48 HOURS AS THE HIGH AND 
RIDGE WEAKEN. MEANWHILE NORTHERLY WINDS TO 20 KT EXIST NE OF THE 
RIDGE...N OF 24N BETWEEN 117W AND 128W ALTHOUGH THESE WINDS 
SHOULD DIMINISH TO LESS THAN 20 KT WITHIN THE NEXT 24 HOURS AS 
THE PRES GRADIENT IN THAT AREA WEAKENS.

NORTHERLY SWELLS OF 8 TO 12 FT OVER THE 20 TO 25 KT WIND AREAS 
ARE COMMINGLING WITH CROSS EQUATORIAL SW SWELLS WHICH NOW EXTEND 
WELL N OF 32N TOWARD THE U.S. WEST COAST. 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 HOURS.

$$
LEWITSKY