000
AXPZ20 KNHC 171537
TWDEP 

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1605 UTC SAT MAY 17 2008

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

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 
1515 UTC.

...TROPICAL WAVES...

A TROPICAL WAVE EXTENDING FROM 03N78W THROUGH 06N79W TO 10N79W 
IS MOVING WESTWARD AT 10-15 KT OVER THE GULF OF PANAMA. 
ASSOCIATED SHOWER AND THUNDERSTORM ACTIVITY IS NOTED FROM 05N TO 
07N BETWEEN 78W AND 81W. 

...ITCZ...

ITCZ AXIS IS ALONG 05N80W TO 07N91W TO 06N97W TO 08N106W TO 
06N115W TO 08N126W TO 04N134W TO 04N140W. SCATTERED MODERATE 
ISOLATED STRONG WITHIN 70 NM S OF AXIS BETWEEN 85W AND 88W. 
SCATTERED MODERATE FROM 04N TO 06N BETWEEN 95W AND 98W. 
SCATTERED MODERATE ISOLATED STRONG WITHIN 115 NM N OF AXIS 
BETWEEN 107W AND 111W.

...DISCUSSION...

N OF 20N...
A RATHER STAGNANT AND COMPLEX HIGH ZONAL UPPER LEVEL PATTERN 
DOMINATES THE NORTHERN PORTION OF THE DISCUSSION AREA. THE 
SYNOPTIC FEATURES CONSIST OF A CUT-OFF LOW NEAR 25N138W...A 
BLOCKING HIGH N OF THE AREA OVER NORTHERN CA AND ASSOCIATED 
RIDGE AXIS EXTENDING SOUTHWARD ALONG 125W N OF 26N...AND A BROAD 
TROUGH STRETCHING WEST-SOUTHWESTWARD FROM OK/TX...OVER CENTRAL 
BAJA CA TO 28N124W. MULTI-LEVEL CLOUDINESS WITHIN UPPER 
DIFFLUENT FLOW E OF THE CUT-OFF UPPER LOW IS SITUATED BETWEEN 
123W AND 134W. A FEW LIGHT SHOWERS EXIST WITHIN THIS PLUME OF 
MOISTURE N OF 24N. MODERATE SUBSIDENCE/DRY CONDITIONS ASSOCIATED 
WITH THE SW U.S./BAJA CA TROUGH PERSIST OVER THE NE REGION E OF 
123W. AT THE SURFACE...DURING THE NEXT 24-48 HOURS...N TO NE 
FLOW SHOULD REMAIN LESS THAN 20 KT AND A NW SWELL IS EXPECTED TO 
BE WITHIN THE 6 TO 7 FT RANGE WITH A LONG 10-13 SECOND PERIOD.

S OF 20N...
MID TO UPPER TROPOSPHERIC RIDGE AXIS EXTENDS WESTWARD ALONG 13N 
FROM CENTRAL AMERICA TO 122W. SHOWER AND THUNDERSTORM ACTIVITY 
IS SITUATED S OF THE AXIS...PRIMARILY ALONG THE ITCZ...BENEATH 
UPPER EAST TO SOUTHEASTERLY FLOW. AT THE SURFACE...AN INVERTED 
TROUGH OF LOW PRESSURE...EMBEDDED IN THE ITCZ...ALONG 105W FROM 
06N TO 12N IS AIDING IN THE PRODUCTION OF AN AREA OF 
DISORGANIZED CONVECTION W OF THE TROUGH FROM 06N TO 11N BETWEEN 
108W AND 113W.   

$$
ROBERTS