Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 281530

Area Forecast Discussion
National Weather Service Denver/Boulder CO
830 AM MST Tue Feb 28 2017

Issued at 820 AM MST Tue Feb 28 2017

Upper level trof to move across Colorado this afternoon and early
evening. Best QG forcing will be during the day as initial band of
snow has developed over Elbert, Lincoln and Southern Washington
counties this morning. NAM has the best idea on precip placement
while HRRR/RAP are too far north and ambitious with this
development. Have made some adjustments to forecast to account for
this morning showers over southern portions of CWA. Best snow
potential will be this afternoon/early evening over the plains
with modest instability. Not much of an upslope component but
winds try and turn back Easterly with surface low pressure over
Southeast Colorado. Snowfall amounts generally an inch or less
but possible up to 2 inches in heavier bands. Still potential
impact with heaviest potential of snow coming in during commute
times later this afternoon. Duration only a few hours with quick
moving trof.


.SHORT TERM...(Today and tonight)
Issued at 152 AM MST Tue Feb 28 2017

Jet max along the CO/WY border this morning shifting to the east
with a some decrease in snow showers across ZNEs 31 and 33. latest
radar mosaic this morning however showing snow with heavier
enhanced bands along I-70 west of Vail. Main concern for snowfall
today will be associated with this band as the main trough axis
moves across the state. The stronger jet by later this morning
will be over southern and eastern CO. The bands are progged to
translate eastward into the cwa ahead of the main trough axis
later this morning and afternoon. Some concern the bands will
extend a little further north this morning as possibly spread into
ZN33 briefly so have extended the winter weather advisory there
until until 11 am. Best instability will occur along the
Interstate 70 Corridor in closer proximity to the banded
snowfall. Will keep the Winter Weather Advisory for ZN34 in
effect through 5 pm the aftn. The HRRR mdl still generating some
decent qpf in the Denver area around 00z. NAM12 forecast sounding
show a brief period of good instability in a saturated airmass
this afternoon. As a result, some concern for a quick burst of
snow around 00z. Will keep the mention of an inch of snow in the
grids for Denver and for areas south and east as well. Also added
isolated thunder the grids at that time.  By early this evening,
increasing mid level subsidence develops strong northwest winds
developing in the mountains, foothills and adjacent plains after
03z this evening. No highlights, but areas in and near the
foothills could see some gusts in the 50-60 mph range. Snow will
decrease but could still get 1-3 inches along the higher north and
west facing slopes with areas of blowing snow along and east of
the Continental Divide.

.LONG TERM...(Wednesday through Monday) Issued at 152 AM MST Tue
Feb 28 2017

An upper level ridge building along the west coast will produce a
northwest flow aloft across the Central Rockies. A few snow showers
will be possible over the mountains, otherwise it will be dry.
Temperatures are expected to be cool under this pattern with highs
in the upper 30s to lower 40s.

Thursday and Friday will be dry under westerly flow aloft.
Temperatures will begin to warm. Highs on Thursday should be near
normal. By Friday, high temperatures are expected to be above normal
with mid to upper 50s expected across northeast Colorado.

For the weekend, westerly flow aloft will turn to the southwest
Sunday as an upper level trough moves over the Pacific Northwest.
Temperatures will be very mild this weekend with 60s expected over
northeast Colorado. Can`t rule out a few 70s on Sunday. As the upper
level trough moves across the Northern Rockies Sunday and Monday, it
could bring light snow to the northern mountains. Will have low pops
for this on Sunday. A cold front behind the trough is expected to
slide across eastern Colorado Monday. This will bring cooler
temperatures, however readings should remain above normal. No
precipitation is expected with this front.


.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 820 AM MST Tue Feb 28 2017

expect lower ceilings/IFR this afternoon with best potential for
snowfall from 21z-00z and then improving during the evening hours
as stronger downslope flow kicks in following trof passage. Snow
accumulations still look to be around an inch with lower
probabilities of up to 2 inches.


Winter Weather Advisory until 11 AM MST this morning for COZ033.

Winter Weather Advisory until 5 PM MST this afternoon for COZ034.



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