480 
fxus65 kcys 060832 
afdcys 


Area forecast discussion 
National Weather Service Cheyenne Wyoming 
232 am MDT Sat Sep 6 2008 


Short term...today through Sunday night. 
Early this morning...numerous rain showers and the possibility 
for an isolated thunderstorm will continue to be present through 
around sunrise this morning across the Nebraska Panhandle and 
extreme southeast Wyoming. Areas of fog will be present along 
Interstate 80 over The Summit between Cheyenne and Laramie...and 
patchy fog will be possible elsewhere east of the Laramie range. 


Today...the shower activity will continue to be present across 
areas east of the Laramie range beneath the favored left-exit 
region of a strong jet streak in northwest flow aloft. This short- 
wave disturbance will shift eastward today...with the best 
conditions for lift also moving east. Have represented this by 
shifting precipitation chances north and east and slightly 
decreasing these during the afternoon. As precipitation decreases 
and the upper ridge shifts east slightly...temperatures will be 
much warmer and closer to normal than those observed Friday. A 
surface cold front will begin to move south across the area during 
the late afternoon with gusty north winds accompanying the frontal 
passage. 


Tonight...the precipitation will dissipate across the area as the 
cold front continues to move through and produce gusty north 
winds. Winds will weaken behind the front during the overnight 
hours. Areas of low stratus clouds and patchy fog can again be 
expected to form by around sunrise. 


Sunday and Sunday night...slightly cooler temperatures will be 
observed Sunday. Yet another reinforcing cold front begins to 
take shape over Idaho and western Wyoming Sunday as a result of 
the energy in the northwest flow aloft. Surface pressure falls are 
forecast to occur in this area beneath the right entrance region 
to one jet streak...combined with the left exit region of another 
jet streak moving south across extreme western Montana. This set- 
up will increase moisture advection on southeast boundary level 
flow into the forecast area...and the combination of the surface 
frontal boundary and energy aloft will create favorable conditions 
for a fairly significant rainfall event east of the Laramie range 
Sunday night. Will keep precipitation chances below likely wording 
with this forecast package...but confidence is increasing for 
precipitation during this period. 


Long term...Monday through Friday. 
Any lingering showers will move out of the County Warning Area Monday morning as 
upper trough exits the region to the east. Temperatures on the cool 
side for Monday as surface high moves across the Central Plains. Dry 
and warmer conditions will then return for Tuesday and Wednesday 
as return flow sets up at the surface and heights rise over the 
region. Next upper trough to affect the area should move across the 
northern rockies into the northern plains Wednesday and Thursday. 
Not a lot of weather expected as the system will pass well north 
of the County Warning Area along with the better dynamics but system will push a 
Pacific front across the County Warning Area Wednesday night bringing a little cooler 
air for Thursday. Warmer again Friday as upper ridging over the 
western Continental U.S. Shifts eastward toward the region. 


&& 


Aviation... 
areas of MVFR...with localized IFR in the heaviest rain 
showers... will continue to be present early this morning. Low 
ceilings will begin to rise by around 15z...with VFR conditions 
expected through the rest of the day. Support for showers will 
shift northeast today with showers continuing northeast of a line 
from near kcpr to kibm. Expect patchy fog and low ceilings east 
of the Laramie range again Saturday night...creating areas of 
MVFR and localized IFR conditions. 


&& 


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


&& 


$$ 


Short term/aviation...CArpenter 
long term...re