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fxus65 kcys 111038 
afdcys 


Area forecast discussion 
National Weather Service Cheyenne Wyoming 
338 am MST Thursday Mar 11 2010 


Short term...today through Friday night... 
today...primary challenge will be wind speeds...particularly 
across western Nebraska. Surface through 700 mb gradients will be 
relatively strong and with 500-300 mb qg downward motion couplet 
this afternoon...expect stronger winds to be transported to the 
surface...thus have issued a Wind Advisory for all of western 
Nebraska except Dawes County. Expect 40 knot 700 mb winds to be 
capable of being transported to the surface. 


Isolated to scattered snow showers will decrease in coverage this 
afternoon as low and middle level moisture wanes and the upper trough 
moves further east across the Midwest states. 


Tonight...dry with lack of low and middle level moisture and lift. 
Winds will subside in the evening with some decoupling and 
relaxation of gradients. 


Friday...warmer day on tap with high temperatures in the 40s to 
lower 50s with 1000-500 mb thicknesses near 5490 meters and 700 mb 
temperatures near -4 celsius. 


Friday night...transitory shortwave ridge moves across Wyoming 
keeping our weather dry. 


Long term...Saturday through Thursday... 
a broad Rex block downstream will impact the pattern progression 
across the western Continental U.S. This weekend...before the pattern turns more 
progressive next week. Initially...an upper ridge axis will be 
centered over the intermountain west on Saturday...as the region 
is caught between a large upper low to the east...and an 
approaching trough moving onto the Pacific coast. So...Saturday 
will be dry...with temperatures moderating into the 40s...with low 
to middle 50s in lower elevations east of the mountains. Clouds will 
slowly be on the increase...especially late Saturday...as the West 
Coast trough splits sending a piece of energy north...and an 
eventual cut-off low south of the area. Given the proximity of the 
synoptic forcing associated with the southern cut-off low...have 
added some slight probability of precipitation to the mountains late Saturday night...and 
to all lower elevations west of the mountains on Sunday. There 
will not be much moisture to work with...so expect any snow to 
remain very light. The southern stream energy will drift south and 
by Sunday night a drier air mass will be in place. By Monday...the 
beginning of the next quiet period will be upon the area...as the 
next upper ridge will build over the intermountain west. This 
upper ridge will maintain dry conditions Monday through Wednesday 
night. Temperatures will also be quite mild as 700mb temperatures 
reach freezing...which would yield 60f at 5 kft fully mixed. Have 
kept temperatures around the mean ensembles...but even these may need 
to be bumped up some...especially if these warm 700mb temperatures are 
realized. Both the European model (ecmwf)/GFS are suggesting the next system will 
move in next Thursday...so for now have introduced climatology probability of precipitation 
across the area. 


&& 


Aviation... 
initially...MVFR ceilings/visibilities can be expected at all terminals at 
least for a few hours this morning. A gradual return to VFR is 
expected from west to east through the day. MVFR conditions will 
linger the longest at Nebraska airports...which may not return to 
VFR until late this afternoon. Otherwise...northwest winds ramp up 
today...with 25 to 35 miles per hour with gusts at high as 45 miles per hour expected 
for locations east of the mountains. This will create turbulence 
especially in and around the mountains today. Winds will subside 
some overnight...but another windy day is expected on Friday. 


&& 


Fire weather... 
no fire weather concerns through Friday night. 


&& 


Cys watches/warnings/advisories... 
Wyoming...none. 
NE...Wind Advisory from 7 am Thursday to 5 PM Thursday for nez003- 
nez019-nez020-nez021-nez054-nez055-nez095-nez096. 


&& 


$$ 


Short term/aviation...Rubin 
long term...Hahn