Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 172024
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
224 PM MDT Tue Apr 17 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 218 PM MDT Tue Apr 17 2018

Upper level trough will move east of the Central Rockies this
evening. Strong west to northwest winds are expected to continue
through the afternoon. Winds will then slowly decrease through the
evening hours. Lift associated with the trough will also move
east of the area taking most of the precipitation with it. Some
snow showers may linger through the evening hours in the
mountains. Any additional snowfall is expected to be light and
less than 2 inches. Airmass behind this system is chilly with lows
falling into the upper 20s to lower 30s. Surface high pressure
moves over the area for Wednesday. This will bring mostly clear
skies and slightly below temperatures. Windy conditions will
linger into the afternoon over far eastern Colorado, otherwise
light winds will prevail.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 218 PM MDT Tue Apr 17 2018

For Wednesday night into Thursday increased subsidence with the
incoming upper level ridge will continue the warm and dry pattern
across the state. Temperatures will be slightly warmer than
Wednesday with 700 mb values +5 degrees C warmer bringing highs in
the upper 60s. The main story of the long term continues to be the
storm moving onshore by California Thursday morning that is
currently forecasted to impact Colorado by late Thursday through
Friday. Southwest flow ahead of the upper closed low will increase
by Thursday afternoon. A deepening surface low pressure system over
eastern Utah will help to increase the pressure gradient over the
eastern plains and pull mid-level moisture up from the plains. This
will help to bring some gusty winds by the late afternoon and
evening to the plains as well as increasing clouds ahead of the main
system.

By Friday morning both the EC and the GFS have the 551 DM closed low
over Utah with increasing lift associated with the approaching jet
moving into southern CO. Precipitation is forecasted to start over
the mountains by the morning hours on Friday with the potential for
some thunderstorms by the afternoon over the higher terrain. Out on
the plans precipitation will most likely start out as rain with
coverage over most of the NE plains and Front Range. There is a cold
front expected to bring in increased NE winds and colder
temperatures in the mid levels by Friday night. Current model
soundings indicate a column cold enough for snow with decent QG lift.
With the NE flow and cooler air pooling against the foothills cold
air damming could bring decent snowfall amounts to the foothills by
early Saturday. QPF values still vary between models but numbers are
progressively higher along the foothills and Monument hill areas
where upslope is expected to be the best. However, most areas will
see precipitation accumulation by Saturday afternoon. Models
indicate a stacked low over SE Colorado by Saturday morning that
will slow the systems progression and push precipitation into the
late afternoon hours on Saturday. Temperatures will drop slightly
with below freezing in the mountains and 40s to 50s on the plains
with freezing overnight. As dry air intrudes to the south of the
closed low it will push the system into the TX Panhandle by Saturday
evening. Wrap around from the low will continue to bring some
rain/snow to the NE plains before gradual clearing overnight into
Sunday.

For Sunday into Monday upper ridging and subsidence will return with
a warming trend. At this time temperatures are looking to once again
scratch the 70 degree mark by Monday.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 218 PM MDT Tue Apr 17 2018

West to northwest winds gusting to 35 to 50 knots are expected to
continue through 00Z. Due to the strong winds there is a
potential for reductions in visibility due to blowing dust. Around
sunset winds should gradually decrease to 15 to 30 knots and
continue to slowly decrease overnight. Winds will be weaker
Wednesday and become easterly after 18Z. Scattered to broken mid
and high clouds will decrease after 00Z with mostly clear skies
for tonight and Wednesday.

&&

.FIRE WEATHER...
Issued at 218 PM MDT Tue Apr 17 2018

Strong winds and extreme fire danger will continue through the
afternoon. Conditions will slowly improve this evening as
humidities increase and winds decrease. For Wednesday, high
pressure will settle over the area. Other than some gusty
northerly winds over far eastern Colorado, weak winds are
expected.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 9 PM MDT this evening for COZ050-051.

Red Flag Warning until 8 PM MDT this evening for COZ239>241-
245>247.

High Wind Warning until 9 PM MDT this evening for COZ038-040-
042>049.

Red Flag Warning until 6 PM MDT this evening for COZ214-216.

High Wind Warning until 6 PM MDT this evening for
COZ035-036-039-041.

&&

$$

SHORT TERM...Meier
LONG TERM...Bowen
AVIATION...Meier


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