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fxus65 kbou 251642 
afdbou

Area forecast discussion
National Weather Service Denver/Boulder Colorado
942 am MST Sat Feb 25 2017

Update...
issued at 935 am MST Sat Feb 25 2017

Moisture approaching from the northwest as evident on h20 vapor
satellite imagery already showing up as increasing mid-level
clouds west of the Continental Divide and high cirrus east of The
Divide. Should see this trend continue through the afternoon with
scattered rain/snow showers developing on the West Slope and a
thickening mountain wave cloud band forming over the I-25 urban
corridor. The increase in cloud cover will slow warming except in
and near the Front Range foothills where gusty downslope winds
later today will help to warm temperatures. Precipitation is not
likely east of The Divide today. Changes have been made to today's
forecast to reflect these conditions.

&&

Short term...(today and tonight)
issued at 346 am MST Sat Feb 25 2017

Drier air moving over Colorado today as northwest flow aloft
increases a bit. There will still be some mid/high level clouds as
well as some weak lower level clouds upstream of the mountains,
but only patches of very light snow for the mountains this
morning. With some heating and increasing moisture this afternoon
mountain showers will increase again. This will be a shallow layer
of instability but with decent wind, so it should be mainly light
to moderate showers. Most of the mountains should get a little
snow through the evening, then drier and subsident air will move
in from the north after midnight. For the plains there will be
mid/high cloud cover and possible some weak late day convection,
but with dry low levels expect this will only produce virga.

Forecast temps look pretty good today, lowered tonight's low a
little as we were above guidance and with clearing expected it
could be just as cold in northern valleys and plains low spots as
it is this morning.

Long term...(sunday through friday)
issued at 346 am MST Sat Feb 25 2017

Aside from some residual snowfall in the mountains along the
higher west facing slopes, Sunday and Sunday evening will be dry.
The models show weak qg descent through the day, under a light
west/northwesterly flow aloft. The flow aloft will increase and
become more west/southwesterly late Sunday night into Monday.
Weak qg ascent will develop over the cwa as the next storm system
approaches the state from the Pacific northwest. The first system
will move across the cwa Monday afternoon. Southwesterly mid
level winds will favor zone 31 the most. The trough axis will pass
to the east Monday evening allowing the mid level winds to
transition to northwest. The best round of accumulating snowfall
will occur Monday afternoon and evening. Moderate mid level
subsidence kicks in after 06z Tuesday which will allow for mainly
light orographic snowfall in the high country. Across the
northeast plains, spatial cross-sections show some shallow
moisture around late Sunday night, but mostly dry aloft so no pcpn
anticipated through Monday night altho there could be some
stratus stirring around the northeast plains. The mdls push the
cold front across the area 03-06z Monday evening. The second part
the storm system push across the Desert Southwest 12z Tue and
clips southern and eastern Colorado Tuesday aftn/evng. The mdls develop
a weak sfc low near the OK/Texas panhandles Tuesday aftn, then flush
the sfc low eastward Tuesday evening. The mdls show a brief window
for snow mainly for east central co, so maybe some light
accumulations to the east/southeast of Denver late Tuesday
aftn/evng. High pressure at the sfc and aloft will allow for a
drier pattern by the middle of next week and continuing into next
weekend, with temperatures climbing back to around 60 by Saturday.

&&

Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 935 am MST Sat Feb 25 2017

Light and variable winds at the present time at Denver area
Airport terminals are forecast to gradually turn west-southwest
during the late morning or early afternoon hours. By mid-
afternoon...speeds in the 8-14 kts will become common with
possible gusts to around 25 kts at kbjc near the base of the
foothills. Otherwise for the rest of the day count on VFR
ceilings under a thickening nearly stationary mountain wave cloud
with its base generally at or above 15000 ft above sea level.



Bou watches/warnings/advisories...
none.
&&

$$

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