000
AXPZ20 KNHC 150336
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SAT MAY 15 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 
0245 UTC.

...TROPICAL WAVES...

A WEAK TROPICAL WAVE IS ALONG 89W FROM 02N TO 09N MOVING W AT 10 
KT. THE WAVE COINCIDES WITH A MAXIMUM IN TOTAL PRECIPITABLE 
WATER IMAGERY. ISOLATED MODERATE CONVECTION IS MAINLY ALONG THE 
ITCZ.

...ITCZ...

ITCZ AXIS IS ALONG 06N77W TO 08N100W TO 08N112W TO 08N123W TO 
07N140W. SCATTERED MODERATE CONVECTION IS WITHIN 150 NM S OF THE 
AXIS BETWEEN 95W AND 98W...WITHIN 60 NM N OF THE AXIS BETWEEN 
121W AND 125W...AND WITHIN 90 NM S OF THE AXIS BETWEEN 130W AND 
134W.

...DISCUSSION...

AN UPPER LEVEL TROUGH EXTENDS FROM NORTHERN MEXICO TO SOUTHERN 
BAJA CALIFORNIA AND TO THE SW-W TO 21N120W TO 17N140W. VERY DRY 
AIR IS IN PLACE N OF THE TROUGH TO 25N UNDER MODERATE TO STRONG 
SUBSIDENCE. A WEAK SHORTWAVE UPPER TROUGH IS CLIPPING THE NE 
PORTION OF THE AREA EXTENDING FROM NORTHERN BAJA CALIFORNIA TO 
29N122W. AN UPPER RIDGE IS IN PLACE W OF THE TROUGH REACHING 
FROM 24N133W TO 32N132W WITH ANOTHER UPPER LEVEL TROUGH NOW 
APPROACHING THE FAR NW PORTION OF THE AREA.

AN UPPER ANTICYCLONE IS CENTERED NEAR 10N105W WITH A BROAD RIDGE 
EXTENDING TO THE E ALONG 10N TO COSTA RICA...AND TO THE W ALONG 
10N TO 140W. THIS RIDGE ALSO COVERS CENTRAL MEXICO SE TO 
NICARAGUA. A JETSTREAM BRANCH WITH CORE WIND SPEEDS OF 70-90 KT 
LIES BETWEEN THE AFOREMENTIONED TROUGH AND THIS ANTICYCLONE 
ENTERING THE DISCUSSION AREA NEAR 16N140W AND CONTINUING TO THE 
NE-E AROUND THE NORTHERN PERIPHERY OF THE ANTICYCLONE AND INTO 
CENTRAL MEXICO. THIS JET IS ADVECTING MID TO UPPER LEVEL 
MOISTURE FROM THE DEEP TROPICS S OF HAWAII UP ALONG ITS AXIS. 
THE RIDGE IS HELPING TO INDUCE CONVECTION ALONG THE ITCZ. IN 
ADDITION A DIFFLUENT PATTERN ALOFT IS ENHANCING CONVECTION ALONG 
THE E PACIFIC COASTS OF COLOMBIA...COSTA RICA AND PANAMA.

AT THE SURFACE...1026 MB HIGH PRES IS CENTERED NEAR 31N139W WITH 
A BROAD RIDGE AXIS EXTENDING ACROSS THE MAJORITY OF THE 
DISCUSSION AREA TO NEAR 12N106W. NE TRADES OF 20 TO 25 KT ARE ON 
THE SW SIDE OF THE RIDGE FROM 10N TO 21N W OF 122W. THE AERIAL 
EXTENT AND STRENGTH OF THE TRADES WILL DECREASE DURING THE NEXT 
48 HOURS AS THE HIGH AND RIDGE WEAKEN. NE SWELL IS COMMINGLING 
WITH SW SWELL OVER THE AREA OF TRADES AND S TO THE EQUATOR WITH 
LONG PERIOD SW SWELL DOMINATING THE REMAINDER OF THE AREA. THE 
SEA STATE WILL BECOME MORE COMPLEX DURING THE NEXT 24-48 HOURS 
AS A SET OF LONG PERIOD SE SWELL BEGINS TO PROPAGATE N OF THE 
EQUATOR.

A 1008 MB LOW IS CENTERED NEAR 07.5N101.5W WITH SCATTERED 
MODERATE CONVECTION OCCURRING WITHIN 180 NM OF THE LOW CENTER 
IN THE NW...SE AND S QUADRANTS. THE LOW IS UNDER THE ABOVE 
MENTIONED UPPER ANTICYCLONE WHICH WOULD BE FAVORABLE FOR IT TO 
MAINTAIN ITSELF AS IT MOVES TO THE W AROUND 5-10 KT DURING THE 
NEXT 24-48 HOURS.

A NEARLY STATIONARY 1010 MB LOW IS CENTERED NEAR 08N112W WITH A
TROUGH EXTENDING FROM 04N113W TO 11N113W. CONVECTION THAT WAS 
ASSOCIATED WITH THESE FEATURES HAS DISSIPATED AND THE LOW IS 
ALSO EXPECTED TO DISSIPATE WITHIN THE NEXT 18-24 HOURS AS IT 
CONTINUES TO MOVE TO THE W INTO AN AREA OF DRIER AIR AND 
INCREASING UPPER LEVEL SHEAR.

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 IN LESS THAN 24 HOURS.

$$
LEWITSKY