375 
fxus63 kfgf 081957 
afdfgf 


Area forecast discussion 
National Weather Service Grand Forks ND 
157 PM CST Thursday Jan 8 2009 


Short term (thu-sun)... 
a Winter Weather Advisory was issued for the southern Red River and 
areas west of the valley...mainly for snow as low pressure passes 
the Dakotas this evening into Friday. 


The models are in fairly good agreement with this upcoming 
system...but the NAM and European model (ecmwf) are slower. This forecast relied 
more on the faster GFS...pushing most of the snow out of the area 
by Friday afternoon. 


An advisory was the better way to go due to the latest model runs 
indicating less snowfall. Plus...precipitable water content backed 
off...with the 0.5 inch line likely further into South Dakota. 
Still...a stretch of 3 to 5 inches of snow is anticipated from 
Jamestown to Forman. This lines up fairly well with the strongest 
frontogenesis at 6z Friday. A snow ratio of about 15/16 to 1 was 
used. The wind overnight is not expected to cause any blowing 
snow. Most of the snow should fall late this evening through early 
Friday morning. Temperatures should hold fairly steady overnight across the 
southern forecast area due to some warm air advection. The northern forecast area 
should see falling temperatures due to fewer clouds and insignificant 
warm air advection. Winds do pick up after dawn Friday...mainly across the southern 
valley and areas to the west of the valley. Since winds are not 
looking too impressive through Friday afternoon...backed off on 
blowing snow for all but far southeastern North Dakota and well 
west of the valley. Some light snow could linger through the 
afternoon...especially if the slower NAM and European model (ecmwf) pan out. Cooled 
Friday temperatures a bit. 


Sat and sun...models in good agreement about high pressure passing 
the Dakotas and Minnesota Friday night into Sat. The northern plains 
gets some warm air advection Saturday...with 10 to 15 knot southwesterly winds. 
Models agree about a trough passing the area Sat night with some 
possible very light snow. Increased northwesterly winds Sunday. 
If mixing looks stronger...may need to increase the winds even 
more. Few temperature changes were made for the Sat to sun period. 


Long term (mon-thu)... 
it looks like an Arctic outbreak is in store for the middle of next 
week. The GFS/European model (ecmwf) are consistent with a 1050+mb high building down 
into the northern plains. This will mean temperatures bitterly cold 
along with dangerous wind chills if we are in the pressure gradient. 
If we are not in the pressure gradient...air temperatures may approach -35 
to even -40 in some areas. Did not go this cold yet with some wind 
expected...but very cold to say the least. There is also the chance 
for some light snow Monday/Tuesday ahead of the cold plunge. 


&& 


Aviation... 
southern and western taf sites will fall into the IFR range 
overnight from snow and lower ceilings. Further north...expect mainly 
VFR conditions with winds turning to the north by Friday afternoon. 


&& 


Fgf watches/warnings/advisories... 
ND...Winter Weather Advisory from 9 PM this evening to 6 PM CST 
Friday for ndz006-014-015-024-026-028>030-038-039-049-052- 
053. 


Minnesota...Winter Weather Advisory from 9 PM this evening to 6 PM CST 
Friday for mnz003-029>031-040. 


&& 


$$ 
Grochocinski/dk/jk