966 
fxus65 krev 201704 
afdrev 


Area forecast discussion 
National Weather Service Reno Nevada 
904 am PST Thursday Nov 20 2008 


Update... 
decreased cloud cover for this morning based on visible satellite 
imagery. Shortwave trough prognosticated to move across Oregon through 
this evening while a weak cold front will move into northern California 
and Nevada by middle day. Going forecast looks good with breezy 
conditions this afternoon..especially north of I-80. Radar shows 
band of precipitation from Redding...northward into southern Oregon 
which will bring isolated showers north of Susanville this 
afternoon and more scattered shower activity near Cedarville. 
Mozley 


&& 


Previous discussion... /issued 234 am PST Thursday Nov 20 2008/ 


Short term... 
fast moving negative tilt shortwave currently close to the Oregon 
coastline with the parent low spinning in the Gulf of Alaska. This 
shortwave with send a moderate surface cold front across northern California/Nevada 
today. A dissipating precipitation band along the front will bring a few 
showers to areas near the Oregon border however most showers will 
likely just be virga. The main impact of this system will be 
breezy conditions associated with the front. Southwest winds over 
Sierra ridges currently gusting near 50 miles per hour however valley 
locations have decoupled and remain calm. The front pushes to the 
California/NV/or border by late morning creating breezy conditions over 
locations north of Highway 50. The strongest winds will be over 
locations in the Lee of the northern Sierra and the Warner 
Mountains...however speeds should remain below advisory criteria. 
The front moves through western Nevada and the Reno area late this 
afternoon. The strongest winds in the Great Basin zones will 
likely be behind the front with brisk northwest winds this 
evening. 


The shortwave and surface front quickly exit the area overnight 
with shortwave ridging on Friday. Valley locations should be 
trapped under inversions with temperatures remaining in the low to 
middle 50s. Another shortwave moves into Washington Friday night with 
broken vorticity energy further south over Oregon. This feature also 
has a weak cold front and precipitation band however any showers should 
remain north and west of the County Warning Area. Winds are much less with this 
system with 700 mb winds remaining below 20 kts. Ridging begins to 
push back into the West Coast Saturday night. Jordan 


Long term...Sunday through Wednesday... 
models in better agreement this morning for early next week. Ridging 
for sun/Monday although not as strong as earlier this week. Still 
expect temperatures a few degrees above normal...with the greatest 
departures in the mountains with a moderate low-level inversion. 


For Tue-Wed...GFS/ec/ensembles in very good agreement with a cut-off 
low developing and slowly moving toward the coast for Wednesday. Of course 
details are quite a bit different depending on model/ensemble 
member. That said...still looks like the cut-off will approach the 
coast from 30-35n. Will dry out Tuesday as models are often a bit 
too quick with cut-offs/closed lows. However...will keep slight 
chances for Wednesday and focus them south of Highway 50. With the low that 
far south have a hard time seeing any precipitation with the weak trough 
axis the north even though models show it. It is typically overdone 
3+ days out. Also will gradually cool temperatures mountains with slower cooling 
valleys. With southerly flow ahead of the cut-off...think snow levels will 
remain fairly high 7-8000 feet. Wallmann 


Aviation... 
VFR conditions through Friday. Wind gusts to 30 kts likely for ktvl/ktrk 
and krno between 20z and 03z from a SW-west direction. No significant 
fog formation expected at ktrk for the next 48 hours. Wallmann 


&& 


Rev watches/warnings/advisories... 
Nevada...Lake Wind Advisory until 7 PM PST this evening for nvz002-004. 


California...Lake Wind Advisory until 7 PM PST this evening for caz072. 


&& 


$$ 


Http://weather.Gov/Reno