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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
1004 am MST Sat Feb 13 2016

issued at 939 am MST Sat Feb 13 2016

Have updated the grids to remove the fog advisory along the urban
corridor. Visibilities continue to improve in most areas. Some
patchy dense fog towards Loveland at this time but this will
improve shortly as well. Areas of fog will linger a bit longer
east of Interstate 25 so will maintain this in the grids through
the morning hours. Hazy conditions along the urban corridor this
morning will give way to partly sunny conditions in the
afternoon with mild temperatures. Some gusts in the mountains
above timberline around 50 miles per hour this will adjust to
some higher gusts in the mountains this morning to better reflect


Short term...(today and tonight)
issued at 401 am MST Sat Feb 13 2016

A weak Denver cyclone developed over northeast Colorado last
evening which tapped into a moist airmass over Nebraska and
western Kansas. As the weak easterly flow moved up the South
Platte River Valley last evening...fog developed and became very
dense along the foothills this morning. Fog with visibilities
near zero at times extends from The Fort Collins vicinity down to
the northern and western sections of Denver. Will issue a dense
fog advisory for the I-25 urban corridor for early this morning.
Visibilities should begin increasing an hour or two after sunrise
with all fog across northeast Colorado dissipating by late
morning. Dense fog advisory will continue until 9 am MST.

Not much other weather is expected today as the moderate northwest
flow aloft continues over the state. Moisture will begin
increasing in the mountains late tonight...but any appreciable
snowfall is not expected until later Sunday and Sunday night.
Temperatures on the plains are expected to be warmer than
yesterday...but a foggy start to the morning may hold back the
warming for a few hours. By midday...the middle level west-northwest
flow should be able to mix to the surface bringing warming through
the afternoon hours under partly cloudy skies.

Long term...(sunday through friday)
issued at 401 am MST Sat Feb 13 2016

West-northwest flow aloft will reside over the area sun through Monday. Cross-
sections show moisture will gradually increase in the mountains by Sun
afternoon and continue through Monday. Lapse rates will be moderately
unstable Sun afternoon through Monday with a favorable orographic component.
Thus snow will be likely in the mountains with advisory amounts
certainly possible in some areas. Could even approach warning
amounts in zn 31 if everything were to come together right. Gusty
winds will produce areas of blowing snow over the higher passes
Sunday night into Monday.

At lower elevations a Pacific fnt will move across the plains by
midday with gusty west-northwest winds especially near the Wyoming-NE border. As for
precipitation chances as a weak disturbance moves across late Sun afternoon into sun
evening still could see a slight chance of showers over the plains. As
for highs readings will cool some on sun behind fnt with temperatures in
the upper 40s to lower 50s over northestern Colorado. On Monday a surface Lee trough
will develop east of the mountains with a decent low level gradient
developing. There could be some potential for high winds in the
foothills late Sun night into early Monday if a mountain wave develops however
current cross-sections are only showing a weak wave at this point.
Otherwise expect another windy day especially in the foothills
and near the Wyoming-NE border. With downslope low level flow over northestern Colorado
should see warmer temperatures as readings rise back into the 50s with
near 60 possible around Denver.

For Monday night into Tuesday west-northwest flow aloft will continue however moisture
will gradually decrease in the mountains with lapse rates becoming more
stable. Thus snow chances should diminish on Tuesday. East of the mountains
it will remain dry with downslope west-northwest flow. Once again gusty winds
will continue in the foothills and across the plains especially near
the Wyoming-NE border. As for highs readings over northestern Colorado will range
from the middle 50s to around 60.

On Wednesday the flow aloft will become more westerly with no precipitation expected
across the area. With westerly downslope low level flow in place should
see warmer temperatures with readings in the 60s over the plains. By Thursday a
quick move upper level trough will move across the area by afternoon
into Thursday evening. This feature will bring a chance of snow to the
mountains however over northestern Colorado it will remain dry. Highs over northestern Colorado
will once again rise into the 60s in advance of a Pacific fnt
which will move across Thursday evening. By Friday a flat upper level
ridge will build into the area bringing dry weather with a
continuation of above normal temperatures.


Aviation...(for the 18z tafs through 18z Sunday afternoon)
issued at 939 am MST Sat Feb 13 2016

Better mixing the rest of this morning should allow for the fog to
continue to scour out of the Denver area...still some fog however
near kden 4-5sm restrictions but this should improve to VFR by
18z. Also some fog still trapped near Longmont/Loveland and this
should improve to VFR ceilings and visibilities as well by this
afternoon. No restrictions anticipated after 18z. Weak cyclone still
around with light north/NE winds through 18z at kden...then the hrrr
indicates more of a westerly wind component in the 18-21z
window... then northwest/northerly through 00z this afternoon...north-northeasterly this evening
as a weak front pushes through the Denver area. &&

Bou watches/warnings/advisories...


short term...dankers
long term...rpk

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