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Area forecast discussion 
National Weather Service Medford or 
848 am PST Thursday Jan 8 2009 


Update...National Weather Service WSR-88D shows the 
precipitation shield associated with the cold front moving 
southeast across Modoc County and soon to be exiting the County 
Warning Area entirely. I have made minor adjustments to the grids 
to reflect the departing front and its associated weather. 


&& 


Aviation...visible satellite imagery shows the cloud field 
associated with the cold front moving southeast across the 
southeastern region of the County Warning Area. In the wake of 
thefront...cold air advection is allowing for cumulus to spread 
across the western counties. Gradually improving VFR conditions are 
expected within the next 12 hours for the terminals. 


&& 


Previous discussion... /issued 232 am PST Thursday Jan 8 2009/ 


Discussion...leading edge of the cold front is reaching the 
coast and will move inland early this morning. Winds have picked 
up along the coast with a 64 miles per hour gust at the Cale blanco Coast 
Guard Station. Winds along and at the coast will remain elevated 
for a few more hours...then will decrease in the wake of the 
front. 


The front will move through the County Warning Area this afternoon with rain 
decreasing to scattered showers as an upper level trough swings 
through in the wake of the front. With the front moving through 
the area rather quickly...suspect that the quantitative precipitation forecast amounts suggested by 
the NAM are overdone and adjusted them down some. Still the quantitative precipitation forecast 
bullseye should be centered in southwest Oregon. 


The through will swing east of the County Warning Area tonight which will put an 
end to the showers. Any showers will end this evening with most 
centered over the Cascades. 


500mb heights rise in response to an upper level ridge nosing into 
the area Friday through the weekend with the storm track shifting 
north. The GFS suggest a weak shortwave will move through 
northwest Washington Saturday afternoon and night which will 
flatten out the ridge and bring middle and high level clouds over the 
northern half of the County Warning Area. The European model (ecmwf) shows a stronger ridge which 
if right will limit the middle and high clouds. With ample moisture on 
the ground west of the Cascades...areas of fog is a good bet in 
the overnight period into the morning hours with partial clearing 
by the afternoon for the weekend. Temperatures this weekend will 
warm up..but mostly over the ridges and above the fog layer. 


The European model (ecmwf) and GFS continue to be in similar agreement in the long 
wave pattern showing a large upper level trough setting up shop 
over Hudson Bay and a strong upper level ridge centered in the 
eastern Pacific for next week. The net result from this will be a 
dry and stable pattern. This could lead to an air stagnation 
advisory starting as early as Monday. 


&& 


Mfr watches/warnings/advisories... 
or...none. 


California...none. 


Pacific coastal waters...Small Craft Advisory for hazardous seas 
until 6 PM PST Friday for pzz350-pzz356-pzz370-pzz376. 


$$ 


Kansas/mp