538 
fxus63 klbf 181958 
afdlbf 


Area forecast discussion 
National Weather Service North Platte NE 
258 PM CDT Thursday Mar 18 2010 


Discussion... 
an interesting night is ahead. The nam12 indicates csi bands 
forming across northwest Nebraska marching southeast through the forecast area 
Friday morning. Meanwhile the 12z European model (ecmwf) continues to paint I-80 
with around 0.50 inches of quantitative precipitation forecast. If the NAM is correct with the csi 
and the European model (ecmwf) is correct with its amount and location of quantitative precipitation forecast...bands 
of moderate to heavy snow will develop overnight tonight through 
roughly 15z Friday across southwest Nebraska northeast into Custer County. 
The official forecast uses a 50 50 blend of the wetter European model (ecmwf) and drier 
NAM. With a roughly 15 to 1 snow water ratio...3 to perhaps 6 
inches of snow will accumulate. 


The Winter Weather Advisory has been extended to 4 PM CDT along 
and south of Nebraska Highway 2 and now includes all of southwestern Nebraska. 


It is difficult to gage the strength of snow bands but the 
elevated Theta-E above the cold pool extending from 800 to 700 
mb...Omega and intersecting momentum sfcs extend up to 400 mb at 
times and are Colorado-located with areas of negative epv. Will take 
another look at the 18z NAM. For now the best approach might be to 
wait for the bands to set up on radar and upgrade products as 
warranted. Since none of the models indicate deep strong 
lift...the NAM quantitative precipitation forecast...forecast radar returns...BUFKIT and GFS bufr data 
give no indication of heavy snow. 


North winds should come up to 15 to 25 miles per hour with gusts to around 
35 miles per hour at times this evening. These winds should be decreasing 
throughout the morning from north to south as the Arctic high 
builds in. Light snow tapers Friday afternoon with snow showers 
Friday night as the atmosphere continues to cool and dry aloft. 


Generally clear skies are expected this weekend. The Arctic high 
currently centered near Great Bear Lake will drop through the northern High 
Plains and into Texas. Temperatures in the 30s Saturday should warm 
into the 40s Sunday as downsloping winds develop. 


Strong low pressure developing across the northern High Plains 
Monday should produce another good warm up with highs in the 50s 
to around 60. Both the GFS and European model (ecmwf) are backing another cold 
front into Nebraska Tuesday. Presumably some sort of disturbance 
is expected to cross the central and northern plains Wednesday and 
Thursday. For now rain or snow is possible. Later forecasts will 
obviously refine this. 


&& 


Aviation... 
MVFR conditions will develop by around 03z at kvtn and 06z at klbf 
as upper system moves in. A fall in ceilings to at or below ovc020 will also 
signal -sn with lowest visibilities 1-2sm for kvtn from 04z to 08z and 1sm 
09z to 15z for klbf. Visibilities at klbf may fall blw 1sm at times between 
09z and 15z. North winds behind front will increase to 15kts 
sustained with gusts to 25 kts through end of taf at 18z/19th with 
blowing snow an issue at klbf. 


&& 


Lbf watches/warnings/advisories...Winter Weather Advisory from 7 PM CDT /6 PM MDT/ this evening to 
4 PM CDT /3 PM MDT/ Friday for nez022-035>038-056>059-069>071. 


Winter Weather Advisory from 7 PM CDT /6 PM MDT/ this evening to 
1 PM CDT /noon MDT/ Friday for nez004-005-008>010-023>028-094. 


&& 


$$ 


Short term/extended...cdc 
aviation...roberg