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Area forecast discussion
National Weather Service Denver/Boulder Colorado
332 PM MDT sun may 28 2017

Short term...(this evening through monday)
issued at 331 PM MDT sun may 28 2017

Models continue to show moderate northwesterly flow aloft across
Colorado as an upper ridge builds over the western United States.
At the surface, high pressure building over woming and Montana
will feed cool northerly winds into northeast Colorado that keeps
afternoon temperatures around the 70 degree mark, similar to this
afternoon. Tonight should see skies rapidly clear as diurnal
showers lose the daytime heating and dissipate.

Cross sections show some mid-level moisture moving over the region
tomorrow morning which could be enough to produce some cloudiness.
Through the rest of the day, we should see showers develop over
the mountains an foothills and then drift onto the plains. Model
soundings only show 800-1200 j/kg of cape, so strong storms are
not anticipated. Brief rains, small hail and gusty winds will be
the primary threats. The northerly winds on the plains may also
keep temperatures too cool for the airmass to de-stabilize, in
which the Holiday afternoon would remain a dry one.

Long term...(monday night through sunday)
issued at 331 PM MDT sun may 28 2017

An upper level ridge will extend from the Great Basin to the
Pacific northwest Monday evening. The ridge weakens as it shifts
eastward through the week. By 00z Thursday, the ridge will be
centered over western Colorado, eastern Utah, and western Wyoming.
Only a slight difference in the models on where the ridge axis
ends up. As far as weather GOES, expect scattered showers and
thunderstorms to linger into the evening hours Monday over the
higher terrain and nearby plains. Farther east, isolated
convection may occur. For Tuesday, models continua to show enough
moisture and instability for scattered convection over the higher
terrain with isolated convection for the near by plains. Far
northeast Colorado still appears too stable for convection.
Surface temperatures warm Wednesday as the ridge axis nears. There
are differences among the models where the best convection will
occur. Warming mid levels may help cap convection over western and
central Colorado. The European model (ecmwf) and Gem show the best convection over
the plains. Will lean towards this solution versus the GFS which
shows the best convection over the mountains.

For Thursday, Friday, and into next weekend, will side with the
European model (ecmwf) and the Gem which shows a ridge over the area through this
period. There is a low that moves across the southern rockies
Thursday while a trough move over the top of the ridge across the
northern rockies Thursday. This temporally flattens the ridge
Thursday and early Friday. Thinking the best chance for storms in
this time frame will Thursday when the ridge flattens. For Friday
and next weekend, expect temperatures to warm above normal with
decreasing chances for thunderstorms due to mid level warming
under the ridge.

&&

Aviation...(for the 18z tafs through 18z Monday afternoon)
issued at 331 PM MDT sun may 28 2017

VFR conditions are expected to continue overnight and through
tomorrow morning. Northerly winds will continue through the
evening as weak showers occur over Larimer and Weld counties.
Winds will transition to drainage southerlies through the evening.
A weak surge of northerly winds is expected around sunrise Monday
morning with weak northeast winds continuing through the day as
surface high pressure builds over the northern plains. A few
thunderstorms are expected Monday afternoon that develop over the
foothills and then drift over the adjacent plains. Gusty winds and
light rain will be the primary threat.

&&

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

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