Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 172228
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
328 PM MST Fri Feb 17 2017

.SHORT TERM...(This evening through Saturday)
Issued at 302 PM MST Fri Feb 17 2017

A decent surge of upslope is moving southeastward across the
plains of northeast Colorado. The airmass behind it is not colder
but a bit more moist. Dewpoints have come a bit, about 3-10 F.
The satellite pictures are showing associated cloudiness with the
next upper level trough just getting into western Colorado at
this time. The models have weak westerly flow aloft this evening
and it becomes south-southwesterly by Saturday afternoon and
increases in speed as an upper trough/closed low moves into the
desert southwest by 00Z Sunday. The QG Omega fields have weak
upward motion in the synoptic scale tonight and Saturday. The
boundary layer winds look to become normal range later this
evening. Over the far east, southeasterlies hang on much of the
night. On Saturday south-southeasterly winds seem to dominate in
most place, so the Metro area will likely see a Denver Cyclone
develop by early afternoon. For moisture, it increases overnight
and is fairly pretty deep over the mountains on Saturday. The
plains will mostly have upper level moisture around. The QPF
fields show limited measurable precipitation over the western CWA
tonight and Saturday. The orographic enhancement for mountain
snowfall is poor. Winds speeds are weak and directions are not
good for the north central Colorado mountains. For pops, will go
with "chance"s in the high mountains from about 06Z tonight
through Saturday. No pops for the plains. For temperatures,
Saturday highs are close to today`s highs, perhaps a tad cooler.

.LONG TERM...(Saturday night through Friday)
Issued at 302 PM MST Fri Feb 17 2017

Focus continues to be on one system moving over the forecast are
Sunday evening and then another one in the middle of next week.
Between those two systems, ridging over the area will bring
periods of dry and warm weather.

The first weather disturbance now appears like it will be a
negatively tilted trough lifting over the state from the south
Sunday and Sunday night. Ahead of it, southerly flow will
transport warm and moist air over the state. Snow levels will
begin high, but quickly drop due to evaporative effects of the
falling precipitation. This trough will lift out quickly and be
leaving the state by Monday morning. Mountain areas should pick
up a few inches of snow overnight. Plains locations should see a
round of evening showers which could be rain that changes to snow
as the storm moves out.

Ridging over the state will quickly develop Monday and Tuesday
with dry and warmer temperatures through Wednesday. During the
latter half of the week, the flow pattern across the country will
undergo a transition to more zonal flow as a longwave trough
carves out over the western United States. By Thursday afternoon
the first part of the trough is forecast to be over Colorado with
much cooler temperatures and more unsettled weather. This is still
nearly a week away, so we will watch how later model runs handle
the evolving pattern. For now, cooler and a chance of showers
across the forecast area will suffice.

&&

.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 302 PM MST Fri Feb 17 2017

Decent near due easterly winds are blowing at DIA right now. They
should become southeasterly by 01Z, with normal drainage expected
by 04Z. There should be no ceiling issues at DIA overnight for
Saturday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...RJK
LONG TERM...Dankers
AVIATION...RJK



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