000
AXPZ20 KNHC 310919
TWDEP 

TROPICAL WEATHER DISCUSSION 
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
1005 UTC MON MAR 31 2008

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

BASED ON 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY 
THROUGH 0845 UTC.

...ITCZ...
ITCZ AXIS IS ALONG 07N78W 08N81W 02N102W 09N121W 05N140W. 
SCATTERED MODERATE ISOLATED STRONG CONVECTION 80 NM N OF AXIS 
BETWEEN 115W AND 117W. SCATTERED MODERATE 60 NM EITHER SIDE OF 
AXIS BETWEEN 110W AND 119W.

...DISCUSSION...
MID TO UPPER TROPOSPHERE...A MAJOR SHORTWAVE TROUGH STRETCHES SW 
FROM THE NW CORNER OF THE U.S. INTO THE NW PORTION OF THE 
DISCUSSION AREA NEAR 18N140W. ASSOCIATED STRONG SUBSIDENCE IS 
APPARENT IN THE WATER VAPOR IMAGERY ALONG THE AXIS AND W OF A 
LINE 28N115W SOUTHWESTWARD TO 16N140W. A SUBTROPICAL JET FINGER 
IS SITUATED JUST DOWNSTREAM OF THE AFOREMENTIONED TROUGH AND IS 
SPREADING MOISTURE FROM THE WESTERN PORTION AREA NORTHEASTWARD 
OVER SOUTHERN BAJA CALIFORNIA AND NORTHERN MX. THE EASTERN 
EXTENT OF THE PLUME LIES ALONG 115W AND JUST NORTH OF MAZATLAN 
MX...ENTRANCE TO THE SEA OF CORTEZ. ELSEWHERE....SUBSIDENCE 
PREVAILS SOUTHEASTWARD ALONG THE WEST COAST...N OF 8N AND E OF 
155W...AS AN ANCHORING MID LEVEL HIGH AND UPPER LEVEL 
CONVERGENCE COMBINE TO SUPPRESS CONVECTIVE ACTIVITY.

AT THE SURFACE...A SUBTROPICAL RIDGE EXTENDS INTO THE REGION 
ALONG 26N140W 22N118W 13N102W. NE TO E TRADES 
PERSIST...HOWEVER...HAVE DECREASED FURTHER THIS EVENING TO 15-20 
KT. A RELATIVELY SMALL AREA OF SUSTAINED 20 KT NW TO N WINDS 
REMAIN WITHIN 375 NM W OF THE BAJA CALIFORNIA COAST. EXPECT 
THESE EVENTS TO BE SHORT-LIVED AS THE HIGH IS EXPECTED TO 
BREAKDOWN MON WITH AN APPROACH OF A FRONTAL SYSTEM FROM THE 
NORTHWEST. WINDS BEHIND THE COLD FRONT SHOULD BE 15-20 KT WITH A 
NW SWELL BUILDING TO 9 FT TUE NIGHT.  

GULF OF PAPAGAYO...ALTHOUGH NO SHIPS IN THE VICINITY DURING THE 
PAST 48 HOURS HAVE REPORTED SUSTAINED WINDS OF 20 KT OR FOR THAT 
MATTER...SEAS NEAR 8 FT...THIS EVENINGS QUIKSCAT OVERPASS AGAIN 
INDICATED A FEW 20 KT WINDS. RESEARCH COMPARING NEARSHORE OCEAN 
SURFACE VECTOR WIND RETRIEVALS TO IN-SITU BUOY DATA HAS REVEALED 
A CONSISTENT HIGH BIAS. CONSEQUENTLY...THE FORECAST OF NE TO E 
WINDS OF 20 KT DURING THE NEXT 12 HOURS MAY BE GENEROUS.

$$
ROBERTS