Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

988
FXUS65 KBOU 201106
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
406 AM MST Fri Jan 20 2017

.SHORT TERM...(Today and tonight)
Issued at 400 AM MST Fri Jan 20 2017

Water vapor imagery showing upper level disturbance moving east
and northeast across Southern Colorado this morning. Moisture has
been increasing and ceilings lowering from southwest to northeast
overnight. Radar beginning to show some snow showers developing
over the front range, especially further south over Douglas
county, where could be seeing some moderate snow already. Some
light snow has also fallen over the mountains with snotel and cams
showing generally 1-3 inches overnight.

Appears the focus for the brunt of the precipitation will be over
the Palmer Divide and further south across Lincoln county and
Southeast Colorado today, given closer proximity to the upper
disturbance and best QG ascent. However, lack of any upslope flow
or colder temperature intrusions would expect any snowfall today
will be under 2 inches in the mountains, and around an inch or
less across lower elevations. Given temperatures in the 30s/lower
40s today expect the light snowfall to melt on roadway surfaces
with minimal impact. The exception would be on the Palmer Divide
where higher elevations may see some icy/slick spots this morning.

The system will be exiting into the central plains by this evening
with improving conditions with some clearing over the plains. Weak
orographics will keep scattered snow showers over the higher
mountains but any additional snowfall tonight would be under an
inch.

.LONG TERM...(Saturday through Thursday)
Issued at 400 AM MST Fri Jan 20 2017

A strong jet streak across the western states will push another
quick moving negatively-tilted upper trough over Colorado on
Saturday. The associated surface low will move from Utah to the
OK/TX panhandles by the evening. Moisture should remain in the
mountains with snow picking up Saturday early afternoon through
evening then diminishing. Expect another 1 to 3 inches of
snow for the high country. There could be a few areas over the
adjacent plains including the Palmer Divide that may see some
light flurries, but not expecting accumulation. With
northwesterly flow aloft increasing and the surface gradient
towards the surface low deepening over the central plains,
northwesterly winds will be increasing over the forecast area,
which will keep low temperatures that night moderated, especially
along the foothills.

An upper ridge will build aloft Sunday with a 130kt jet to move
over the area. Gusty northwesterly winds will remain over the
area in the morning then decrease as the surface pressure gradient
relaxes. Look for similar temperatures as Saturday`s near average
readings. Winds aloft will start to turn more southwesterly as an
upper low moves onshore over the west coast and pushes more
moisture into western Colorado. As QG downward motion turns back
upward Sunday evening, look for snow to redevelop over the high
country.

The upper low will weaken slightly and open up Monday, with part
of the energy diving south into central California and another
part moving north of the state in South Dakota. The mountains
should receive good accumulating snow Monday with some showers
possibly moving over the plains, though downsloping should limit
it more to the eastern plains. A cold front will push across the
area late Monday night. As the trough becomes more positively
tilted and pushes east, the forecast area will be under the upper
trough Tuesday and Wednesday before northerly flow pushes it
southeast of the area. This will bring prolonged light to at times
moderate snowfall to the mountains, with a chance of snow to the
plains. After a relatively warm Monday ahead of the cold front,
temperatures through the rest of the week will be cooler, with
highs in the low to mid 30s over the plains. The state will
remain under northwesterly flow aloft through the rest of the
week, with a few ripples of energy progged to bring periods of a
light snowfall, mainly for the high terrain.

&&

.AVIATION...(For the 12Z TAFS through 12Z Saturday morning)
Issued at 400 AM MST Fri Jan 20 2017

Ceilings lowering early this morning with approach of upper level
disturbance. Snow showers already developing south of terminals
but do expect light snow/flurries to develop at terminals through
13z. Could see some MVFR cigs in rain and snow showers through
this morning. Runway surfaces expected to remain wet, but grassy
surfaces should see less than 1/2 inch of snow. Improving
conditions this afternoon as weak disturbance moves into central
plains. Winds will be generally light today, West to Southwest
under 10kt.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...Entrekin
LONG TERM...Kriederman
AVIATION...Entrekin



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.