000
AXPZ20 KNHC 040351
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
0405 UTC SUN MAY 04 2008

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 
0330 UTC.

...ITCZ...

ITCZ AXIS ALONG 05N77W 05N84W 07N92W 05N97W 05N109W 08N125W 
06N136W 06N140W. WIDELY SCATTERED MODERATE WITHIN 80 NM EITHER 
SIDE OF AXIS BETWEEN 85W AND 92W. SCATTERED MODERATE FROM 03N TO 
05N BETWEEN 96W AND 98W. SCATTERED MODERATE TO STRONG WITHIN 45 
NM EITHER SIDE OF AXIS BETWEEN 120W AND 123W.

...DISCUSSION...

W OF 110W...
A BROAD SLOW MOVING MID TO UPPER LEVEL TROUGH EXTENDING SW FROM 
30N124W THROUGH 20N133W THEN TO 19N140W IS PRODUCING MODERATE 
SUBSIDENCE AND DRYER CONDITIONS ALOFT ALONG AND UPSTREAM OF THE 
AXIS N OF 17N W OF 120W. SHALLOW LOW STABLE MARINE LAYER 
CLOUDINESS SPREADS OVER THE NW PORTION OF THE DISCUSSION AREA. 
GLOBAL MODELS AND THE NAVY COAMPS SUGGEST THAT THE CUT-OFF 
TROUGH WILL AMPLIFY SLIGHTLY SUN NIGHT WITH AN APPROACH OF 
MID-LATITUDE PULSE DIGGING SOUTHWARD FROM THE NW PACIFIC. A JET 
FINGER WITH A 100 KT MAXIMA IS MOVING NORTHEASTWARD OUT OF THE 
BASE OF THE AFOREMENTIONED TROUGH AND OVER NORTHERN BAJA 
CALIFORNIA. A RATHER LARGE PLUME OF MOISTURE IS SPILLING OVER 
THE NW PERIPHERY OF AN UPPER ANTICYCLONE SITUATED OVER SOUTHERN 
MX. THE MID TO UPPER LEVEL MOISTURE ENCOMPASSES THE MAJORITY OF 
THE E PORTION OF THE AREA E OF 120W. AT THE SURFACE...SEAS ARE 
EXPECTED TO SUBSIDE AT LEAST THROUGH EARLY MON MORNING. 
AFTERWARD...SOME STRENGTHENING OF THE NLY FLOW OVER THE EASTERN 
PORTION OF THE SUBTROPICAL HIGH ALONG THE SOUTHERN CALIFORNIA 
AND BAJA COASTS IS EXPECTED TO GENERATE A N SWELL 0F 8 TO 10 FT 
OVER NRN PORTION E OF 132W.

E OF 110W...
MID TO UPPER TROPOSPHERIC ANTICYCLONE SITUATED OVER SOUTHERN MX 
SHOULD GRADUALLY BUILD OVER EXTREME EAST PACIFIC AND WESTERN 
GULF OF MX THROUGH THE REMAINDER OF THE WEEKEND...WITH HIGHER 
PRESSURE AT THE SURFACE EXTENDING SOUTHWARD FROM THE NORTHERN 
GULF COAST...OVER THE WESTERN GULF...AND OVER CENTRAL/SOUTHERN 
MX. THIS CHANGE IN THE LARGE-SCALE PATTERN SHOULD CAUSE A 
PREDOMINANTLY LIGHT ONSHORE...GENERALLY WESTERLY...FLOW ALONG 
THE SW MX COAST. ELSEWHERE...SURFACE TROUGH EMBEDDED WITHIN THE 
ITCZ WITH AXIS FROM 02N94W THROUGH 06N94W TO 09N94W. THE SYSTEM 
REMAINS DISORGANIZED WITH DIMINISHING SHOWERS AND THUNDERSTORMS 
CONFINED TO AN AREA FROM 03N TO 05N BETWEEN 96W AND 98W. A FEW 
OF THE GLOBAL MODELS SUGGEST A SLOW WEST-NORTHWESTWARD MOTION 
WITHIN THE WEAK LOW-LAYER EASTERLY STEERING FLOW. SIGNIFICANT 
DEVELOPMENT IS NOT EXPECTED AS THE TROUGH MOVES TOWARD A MORE 
STABLE AIR MASS AROUND WED.

$$
ROBERTS