Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Denver/Boulder Colorado
305 PM MST Wednesday Nov 26 2014

Short term...(this afternoon through thursday)
issued at 305 PM MST Wednesday Nov 26 2014

An upper level ridge over the western states will flatten as it
shifts east over the Great Basin Thursday. This will cause the
northwest flow aloft over Colorado to become west-northwesterly
tomorrow. Some clouds are lingering over the mountains and perhaps a
few flurries too. There is also a slight chance for light snow over
the northeast plains this evening. The hrrr shows a small band
reforming this evening. Not sold on will stick to the
slight chance. If any snow should be light.

A surface high pressure over the eastern plains and a
surface trough along the base of the foothills has kept the cooler
air over northeast Colorado today. The Lee side trough along with
higher pressure over the Great Basin has produced windy conditions
in the mountains and foothills. Temperatures have warmed nicely in
the lower foothills with readings in the upper 40s. As high pressure
shifts east of the region and a surface trough deepens over the
northern rockies...south to southwest winds will flush out the
cooler air over northeast Colorado and lead to mild temperatures for
Thanksgiving. There will still be some moisture at the middle and upper wave clouds are expected at times. This may slow warming
some...but still looks like highs will climb above 60 degrees across
northeast Colorado. Winds will be gusty in the foothills and
mountains again with gusts to 50 to 60 miles per hour in the wind prone areas
of the mountains and foothills.

Long term...(thursday night through tuesday)
issued at 305 PM MST Wednesday Nov 26 2014

..a dry and warm pattern is setting up for Friday through

Starting with Friday a dry airmass will be in place with strong
west-northwest flow aloft. According to model cross-sections a mountain wave
will form Thursday evening into early Friday. Sustained winds of
40 to 45 miles per hour with gusts up to 70 will be possible over the higher
mountain peaks. There is a lack of an inversion layer at mountain
top so it will difficult to bring those winds down to the surface
so higher winds should remain within the mountains.
However...Chinook warming will occur on Friday and aid in getting
areas close to the foothills well above seasonal normals. Current
trends have highs in the lower 70s for the Denver metropolitan. This
would either meet or exceed the current record high for Friday of
72 set back in 1901.

Dry pattern continues into Saturday and early Sunday with
westerly flow becoming more dominant. Winds over the mountains
will continue with gusting to 70 miles per hour still possible over mountain
top. Mountain top stability is still lacking so will keep winds
isolated to the mountains for the time being. Temperatures will
continue to be well above seasonal normals with highs on Saturday
in the upper 60s.

For Sunday...models still indicating a Strong Mountain wave in the
morning with winds continuing to gust to 60-65 over mountain
peaks. The main feature however for this timeframe is an elongated
upper level trough moving through the region bringing a backdoor
cold front into the eastern portions of the state. This will bring
high temperatures down significantly with the plains struggling
to get out of the 40s. Moisture still lacking with this system so
left probability of precipitation out.

For Monday and Tuesday...models are still in disagreement with the
timing of the synoptic features for the next system. The GFS shows
westerly flow with increasing moisture ahead of the front with
little precipitation associated...while the ec has a more northwest flow
with rain moving into the western portions of the state by Monday
morning. Will keep current probability of precipitation with no changes for this period.


Aviation...(for the tafs through 18z Thursday morning)
issued at 305 PM MST Wednesday Nov 26 2014

VFR conditions will prevail the next 24 hours with middle and high
clouds at times. Northeast winds are expected to turn southeasterly
just after 00z at kden and then become southerly by 03z. South to
southwest winds are then expected to prevail the rest of tonight and
Thursday through out the Denver area. Wind speeds should remain less
than 20 knots tonight and Thursday.


Bou watches/warnings/advisories...



Short term...meier
long term...Bowen

National Weather Service Glossary of Abbreviations