Weather

676 
fxus65 kcys 061528 
afdcys 


Area forecast discussion 
National Weather Service Cheyenne Wyoming 
930 am MDT Monday Oct 6 2008 


Precipitation has moved out of the County Warning Area now and skies have cleared 
across most of the area as well. Will update forecast to remove 
mention of morning showers and reduce clouds. 


Previous discussion... 


Short term...today through Tuesday night... 
upper trough axis over central Wyoming currently with associated clouds 
mainly confined to eastern County Warning Area. This axis will be east of the 
eastern Wyoming border by 18z. Kept a low pop going this morning over 
highest mountain peaks and far eastern County Warning Area where a few showers still 
possible. Clouds will decrease this afternoon. Secondary cold 
front over Montana and northern Wyoming will mean breezy and cool conditions 
all day. Clearing skies Monday night with some of the coolest temperatures 
of the season on tap. For now...have added areas of frost. Will 
let day shift determine the need for frost highlight given it 
being fairly late for US into early October. Upper ridge building 
in Tuesday will bring mostly sunny and much warmer weather with 
breezy areas in the mountains and western part of County Warning Area. Ridge 
will flatten Tuesday night with a weak cold front pushing south over 
the County Warning Area. It will remain dry but some clouds will spread in. 


Long term...zonal flow will be over the area on Wednesday with downslope 
winds at the surface. Dry conditions will occur over the County Warning Area. On 
Thursday...a deepening upper trough will move into the western U.S. The 
GFS is faster and open with this system with colder temperatures for 
the County Warning Area...where as the European model (ecmwf) is slower and stronger with this system 
over the western u... not as cold over the County Warning Area. Consensus at 
this point is to lean towards the European model (ecmwf). On Friday...SW flow will 
occur aloft as an upper low forms over Nevada. This will result in 
a slight chance of showers across the forecast area on Friday. For 
Sat...the upper low will move slowly into the Great Basin. SW flow 
will continue aloft over the County Warning Area and moisture will increase over the 
area...resulting in a chance of showers. Snow showers and mixed 
rain and snow showers will occur across the County Warning Area early Sat 
morning. Snow showers will occur over much of the County Warning Area Sat night and 
Sun morning. The upper low will move rapidly into the northern 
plains by late sun...with the upper trough axis moving across the Wyoming 
portion of the County Warning Area. Will keep a chance of showers in the forecast 
for sun. The strong cold front associated with this system will 
move across the forecast area by Friday night with cold air advection 
continuing at the surface on Sat. High temperatures will be around 
normal for Wednesday through Friday...and 10 to 20 degrees below normal for 
Sat and sun. 


&& 


Aviation...some 4000-5000 foot ceilings will remain over western 
Nebraska Panhandle this morning...otherwise VFR conditions are 
expected today and mostly clear skies tonight into Tuesday night. 


&& 


Cys watches/warnings/advisories... 
Wyoming...none. 
NE...none. 


&& 


$$ 


Short term/aviation...jlh 
long term...kmd