000
AXPZ20 KNHC 132145
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
2205 UTC THU MAY 13 2010

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

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
2100 UTC.

...TROPICAL WAVES...

TROPICAL WAVE IS ALONG 86W FROM 01N TO 07N MOVING W AT 10-15 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. SCATTERED 
MODERATE CONVECTION EXTENDS FROM 03N TO 07N BETWEEN 83W AND 87W.

...ITCZ...

AXIS ALONG 04N77W TO 07N102W TO 08N113W TO 06N128W TO 05N140W. 
SCATTERED MODERATE CONVECTION WITHIN 75 NM EITHER SIDE OF THE 
AXIS BETWEEN 82W AND 87W...WITHIN 90 NM S OF THE AXIS BETWEEN 
95W AND 97W...WITHIN 90 NM N OF THE AXIS BETWEEN 100W AND 105W 
...WITHIN 90 NM N OF THE AXIS BETWEEN 111W AND 114W...AND WITHIN 
120 NM S OF THE AXIS BETWEEN 119W AND 122W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM 32N117W TO 25N123W TO 18N140W 
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 25N. 

AN UPPER LEVEL ANTICYCLONE IS CENTERED NEAR 09N111W WITH A BROAD 
RIDGE EXTENDING ALONG 09N BETWEEN 86W AND 140W. A JETSTREAM WITH
PEAK UPPER LEVEL CORE WIND SPEEDS OF 85-100 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 06N87W IS BRINGING DRY AIR S 
FROM CENTRAL AMERICA NW OF COSTA RICA WHICH IS INTERRUPTING THE 
ITCZ CONVECTIVE BELT BETWEEN 87W AND 95W. MEANWHILE UPPER LEVEL 
DIFFLUENCE UNDER THE COLOMBIAN RIDGE IS ENHANCING SCATTERED 
MODERATE CONVECTION OVER COSTA RICA AND PANAMA.

AT THE SURFACE...A BROAD RIDGE STEMS FROM 1029 MB HIGH PRES 
CENTERED JUST NW OF THE AREA NEAR 32N141W AND EXTENDS ACROSS THE 
DISCUSSION AREA TO 12N110W. NE TRADES AT 20 TO 25 KT ARE SW OF 
THE RIDGE AXIS FROM 08N 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 25N BETWEEN 116W AND 127W ALTHOUGH 
THESE WINDS SHOULD ALSO DIMINISH TO LESS THAN 20 KT BY 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 FEW DAYS.

GAP WINDS...NE TO E WINDS AT 20 TO 25 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