616 
fxus66 kmfr 210504 
afdmfr 


Area forecast discussion 
National Weather Service Medford or 
900 PM PST Friday Nov 20 2009 


Discussion...tonight through tomorrow morning...precipitation and 
winds will diminish across the region as the cold front continues 
eastward. Snow levels will drop to around 2500 feet in 
many places on the west side. Models have trended stronger 
recently with next weather system to affect the County Warning Area on Saturday 
night into Sunday morning..as a low pressure center of near 990mb 
will likely move over northern Oregon or southern Washington on 
Sunday. 60 knot southwest winds at 925 mb over coastal waters are 
noted on the latest NAM run. This could be the third system of 
this strength in the past week. Snow levels will range from 4000 
to 5000 feet across the region Sunday morning when the bulk of the 
precipitation arrives. This storm focuses more snow over the 
Cascades than the Siskiyous...but will need to fine tune the 
expected snowfall accumulations with the upcoming model runs as 
they have some variance in recent runs. Wind-related headlines 
will likely be issued for this storm along coastal waters and 
favored inland locations. European model (ecmwf)...GFS...and NAM suggest upper 
ridging developing over or and northern California Monday. Keene 


Long term...long range models are in fairly good agreement in 
building a strong ridge over the region Tuesday-Wednesday. We expect 
during this time overnight and morning valley fog to be common for 
at least the west side...with freezing fog in some areas as valley 
min temperatures dip well into the 30s. The higher elevations 
should have quite nice weather in this time period with plenty of 
sun and highs near 50. Thursday through Thursday night another cold 
front is advertised and we've trended rain chances west to east in 
this period with cooling temperatures. Stavish 


Aviation...flying weather today features MVFR visibility and 
ceilings over the east side with VFR ceilings over the west side. 
Snow will reduce visibilities along the Cascades...Siskiyous...and 
the east side through Saturday morning. Mountain obscuration will 
be prevalent across the region through Saturday. MVFR ceilings 
over rbg and mfr will likely fall to IFR during the nighttime 
hours...and these IFR conditions should continue through at least 
midday Saturday. Keene 


&& 


Mfr watches/warnings/advisories... 
or...Winter Weather Advisory until 1 am PST Saturday for orz027- 
orz028-orz029-orz030. 
Winter Weather Advisory until 4 am PST Saturday for orz025. 


California...Winter Weather Advisory until 1 am PST Saturday for caz080- 
caz081-caz084-caz085. 
Winter Storm Warning until 1 PM PST this evening for caz082- 
caz083. 


Pacific coastal waters...Small Craft Advisory for winds from 10 am 
to 1 PM PST Saturday for pzz350-pzz356-pzz370-pzz376. 
Gale Warning from 1 PM Saturday to 4 am PST Sunday for pzz350- 
pzz356. 
Hazardous seas warning until 4 PM PST Sunday for pzz350-pzz356- 
pzz370-pzz376. 
Small Craft Advisory for winds until 10 PM PST this evening for 
pzz370. 
Gale Warning from 1 PM Saturday to 1 am PST Sunday for pzz370- 
pzz376. 


$$ 


Nk/sn/MS/11