326 
fxus66 kmfr 191644 
afdmfr 


Area forecast discussion 
National Weather Service Medford or 
844 am PST Wednesday Nov 19 2008 


Discussion...no updates are needed for today. The fog will linger 
in the rogue and Illinois Valley into early this afternoon...then 
end up mostly cloudy with middle and high level clouds already moving 
into southwest Oregon. The 12z NAM is a little slower with the 
arrival of the front compared to the 12z GFS and last nights European model (ecmwf) 
run. More than likely well lean towards the faster GFS/European model (ecmwf) 
timing and gradually increase probability of precipitation this evening and overnight 
tonight. Rain will break to showers with snow levels lowering to 
around 4000 feet. Some of the higher passes may pick up an inch or 
two of snow form the showers Thursday afternoon. We'll look into 
this in more details this morning and make any necessary changes 
for the afternoon package. 




&& 


Aviation...fog and low clouds will persist through noon in the 
rogue and Illinois valleys...then will break up with scattered ceilings near 
1000 feet. Middle and high level clouds will linger into the 
afternoon. Fog should not be an issue in the Umpqua basin this 
morning...but ceilings will remain IFR through the morning...then 
should improve to VFR as the low level clouds break up and being 
replaced by middle level clouds near 7000 feet. Visible and ceilings will 
improve at the coast late this morning into the afternoon. VFR 
conditions should prevail today east of the Cascades. 




&& 


Previous discussion... /issued 215 am PST Wednesday Nov 19 2008/ 


Discussion...the axis of a strong ridge lies just to the east of 
the region...while a trough is located off the coast near 145w. A 
southwest flow will continue to feed varying amounts of high clouds 
across the area again today. Both the GFS/European model (ecmwf) are consistent in 
bringing a cold front to the coast Thursday morning then inland 
during the day. This system lacks moisture and good dynamics so not 
expecting any significant precipitation. A weak ridge will build 
over the region Friday...then another system will move onshore 
Friday night. Most of the energy with this next system will remain 
to the north of the region. 


In the extended...the models begin the period in good agreement 
building weak high pressure over the area Saturday through Monday. 
Later Monday into Tuesday the GFS shows a closed low approaching the 
California coast while the European model (ecmwf) has a stretched out trough 
approaching. 


Aviation...coast...areas of IFR conditions this morning improving 
to MVFR this afternoon. Inland...areas of IFR conditions due to 
valley fog this morning becoming VFR this afternoon. 


&& 


Mfr watches/warnings/advisories... 
or...air stagnation advisory until 10 PM PST this evening for orz023- 
orz024-orz026-orz029. 
Dense fog advisory until 10 am PST this morning for orz024- 
orz026. 


California...none. 


Pacific coastal waters...hazardous seas watch from late tonight 
through Saturday afternoon for pzz350-pzz356-pzz370-pzz376. 


$$ 


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