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fxus65 kcys 071925 cca 
afdcys 


Area forecast discussion...corrected wording in update section 
National Weather Service Cheyenne Wyoming 
1223 PM MST Wednesday Jan 7 2009 


Update...winds have been gusting from 55 to 65 miles per hour the past hour 
across eastern Laramie County Wyoming and also across Banner and 
Kimball counties of Nebraska...so have added these to the High Wind 
Warning. The Wind Advisory is no longer in effect in Kimball and 
Banner counties of Nebraska. Rubin 


&& 


Previous discussion... /issued 927 am MST Wednesday Jan 7 2009/ 


Update...based on current winds gusting over 41 miles per hour at Kimball 
and also gusts to 51 miles per hour at Banner Road...40 miles per hour at Bushnell...51 
miles per hour at the Wyoming and Nebraska state line along Interstate 80... 
have hoisted a Wind Advisory for all of the western Nebraska Panhandle 
through 6 PM today. NAM showing decent enough winds in the lower 
and middle levels to support winds exceeding Wind Advisory criteria 
further north across the Nebraska Panhandle and would prefer to err 
on the side of customer service and caution to serve our customers 
and alert them to the brisk winds. Rubin 


Previous discussion... /issued 242 am MST Wednesday Jan 7 2009/ 


Short term...today through Thursday night... 
winds are just now beginning to pick up across southeast Wyoming...with 
Arlington gusting to 65 miles per hour within the last hour. The Medicine Bow 
profiler has increased to 55 kts at the lowest gate just last 
hour. The surface and 700mb gradients will peak between sunrise and 
mid-afternoon. The 700mb Craig to Casper gradient exceeds 90 
meters at 12z...which is quite impressive considering 60 plus is 
usually a low threshold indicator for high winds. Anticyclonic 
upper jet will push overhead with the favored rfq subsident region 
moving through during the morning hours. By late this evening 
winds should tailor off quite a bit. Left the going High Wind 
Warning as is during this timeframe as its areal coverage and 
timing look good. 


Now for the snow...remote snotels within the Sierra Madre and 
snowy ranges are showing 2 to 3 inches has fallen since Tuesday 
evening. An additional 3 to 7 inches are expected through this 
afternoon. Although amounts are still anticipated to remain below 
winter storm criteria...the combination of winds that will gust in 
excess of 50 or 60 miles per hour...particularly on the north end of the 
range...will make for potentially hazardous conditions. By this 
evening...moisture will decrease as swift northwest flow backs to 
the west and a low amplitude shortwave ridge swings overhead. The 
effect will be a decrease in snow through the evening...with 
complete cessation by sunrise Thursday. 


As flow becomes westerly and surface pressures fall in advance of the 
next upstream shortwave...winds will again pick up across Wyoming 
zones on Thursday. Flow will be unidirectional through the layer 
which will set up yet another possible high wind hilite day for 
Thursday...especially for the usual suspects of Arlington and 
Bordeaux. The cold front associated with this trough will work 
into northwest zones Thursday night...so have spread probability of precipitation in a bit 
earlier. 


Adiabatic warming along leeward slopes...will allow temperatures 
to moderate through the period. Temperatures will climb into the 
upper 40s/low 50s east of the mountains today...with upper 50s to 
near 60 for Thursday. 


Long term...Friday through Tuesday... 
surface cold front will push south of the County Warning Area early Friday morning 
with much cooler air and areas of light snow behind the front. 
Bulk of the snow should fall over the mountains with more scattered snow 
showers over the plains. Precipitation coverage will decrease Friday afternoon 
as upper trough axis passes across and surface high settles into the 
Central Plains. Return flow sets up quickly Saturday as Lee 
troffing deepens over the High Plains with warmer air spreading 
back east along with the typical windy conditions close to the 
mountains northwest upper flow will continue over the region into early next 
week keeping temperature in the vicinity of seasonal averages. 
Main problem in late periods is how things will evolve with 
respect to Arctic surge that looks to sink into the plains by 
midweek. Models quite inconsistent with position of Hudson Bay low 
with GFS now farther west and European model (ecmwf) further east. This will affect 
how much cold air intrudes into the County Warning Area. Due to this inconsistency 
will hold the line on current forecast and bring some cooling Tuesday 
and await better consistency. 


Aviation... 
very strong west winds will be the primary concern through this 
evening...primarily at the Wyoming terminals. Gusts in excess of 50 
kts can be expected at krwl...klar...and kcys. Mountain wave and 
turbulent conditions can be expected across all of southeast 
Wyoming. Most airports...with the exception of krwl...can expect 
VFR conditions through the period. MVFR conditions due to low 
ceilings and -sn is anticipated at krwl today. 


&& 


Cys watches/warnings/advisories... 
Wyoming...Winter Storm Warning until 6 PM Wednesday for wyz063. 
High Wind Warning until midnight Thursday for wyz061-wyz062- 
wyz064-wyz065-wyz066-wyz067-wyz069-wyz070. 
NE...Wind Advisory until 6 PM Wednesday for nez001-nez002-nez003- 
nez019-nez021-nez055. 
High Wind Warning until midnight Thursday for nez020-nez054. 


&& 


$$ 


Update...Rubin 
short term/aviation...Hahn 
long term...re