Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 231009

Area Forecast Discussion
National Weather Service Denver/Boulder CO
409 AM MDT Fri Mar 23 2018

.SHORT TERM...(Today and tonight)
Issued at 241 AM MDT Fri Mar 23 2018

An upper level disturbance embedded in SW flow aloft will move
across the area today and exit far nern CO by late aftn or early
evening.  Decent moisture combined with favorable lapse rates will
produce snow in the mtns thru the aftn with zn 31 the most favored,
however, portions of zn 33 and zn 34 may do well too above 10000
feet so will expand advisory into these areas. Areas of convection
will also be possible.

Across nern CO, sfc low pres will be over the ecntrl plains which
will allow for gusty WSW winds by late morning thru the aftn hours
across the Palmer Divide. Meanwhile, as the disturbance mentioned
above moves across this aftn, decent instability will allow for
the development of sct showers and tstms especially over the
plains. By late aftn as subsidence develops behind the
disturbance this will allow for stronger flow aloft to mix down to
the sfc. Thus expect gusty west to northwest winds to develop
along and near the foothills and over most of the plains. Hi res
data suggests there could be a brief window of 60 to 70 mph winds
at the base of the foothills from near Fort Collins to Boulder
between 21z and 01z. At this point not sure how widespread it will
be and it may not last more than an hour or two so will not issue
any highlight. Further east gusts from 40 to 50 mph may occur in
the same time period. As for highs, temps early this morning are
already very mild so will have readings mainly in the lower to mid
70s`s over the plains.

For tonight moisture will gradually decrease in the mtns during the
evening hours with the chance of snow diminishing by 03z.  Across
the plains there will be a slight chc of showers over the far nern
corner early in the evening otherwise it will be dry.  Winds should
subside as well by early evening as a weak cool front moves across
nern CO.

.LONG TERM...(Saturday through Thursday)
Issued at 402 AM MDT Fri Mar 23 2018

Southwesterly flow aloft will dominate the CWA Saturday through
Sunday night. The QG Omega fields show weak upward synoptic scale
energy over the forecast area all weekend. The low level winds
will be south-southeasterly on Saturday, then normal drainage
patterns Saturday night. On Sunday, the NAM shows a cold front
move in during the day with weak upslope behind it. The rest of
the models don`t have this front in until Sunday evening and night.
Moisture-wise, it is pretty sparse Saturday through Sunday. There
is some moisture progged to increase Sunday evening over the
mountains and northeast corner. There is some minor CAPE in the
high mountains late day Saturday, with a bit over the plains in
the evening. The CAPE values are higher late day Sunday and most
of Sunday night mainly over the eastern two-thirds of the plains.
For pops, very little to none in the mountains Saturday through
Sunday with nothing on the plains. Will increase pops to 10 to
40%s Sunday night. Will go with a few thunderstorms Sunday evening
and night. For temperatures, Saturday`s highs are close to or a
bit warmer than today`s. Sunday`s highs are 0-2 C cooler than
Saturday`s. For the later days, Monday through Thursday, the
southwesterly flow aloft decreases on Monday. An upper trough is
expected to move across the forecast area Tuesday into Wednesday.
The trough has an associated closed low well south of the forecast
area. that will decrease the synoptic scale energy that we might
otherwise receive with just an open wave. The models do show some
QPF and colder temperatures Monday through Wednesday. Nothing
significant however.


.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 241 AM MDT Fri Mar 23 2018

Winds remain southerly early this morning but should become more
southwest by 15z or so.  By midday expect winds will become more
westerly as boundaries fm convection over the higher terrain move
across.  With decent mixing winds could be sustained in the 20-30
mph range with gusts above 40 mph at times in the aftn.  By 00z
winds may become more WNW and remain gusty until 02z before a cool
front moves across as winds shift to the NNE.  Overnight winds will
gradually shift to drainage by 06z.


Issued at 341 AM MDT Fri Mar 23 2018

Fire Danger will be critical across southern Lincoln this afternoon
into the early evening hours due to gusty west winds and low
humidity levels.

The Fire Danger will be elevated Saturday afternoon across the
eastern plains and over South PArk and the southeastern CWA on
Sunday afternoon. Saturday is probably the worst day of the two
and needs to be monitored if future model runs increase the winds
speeds a bit or dry the airmass out a bit.


Red Flag Warning from 11 AM this morning to 7 PM MDT this
evening for COZ247.

Winter Weather Advisory until 6 PM MDT this evening for COZ033-

Winter Weather Advisory until 6 PM MDT this evening for COZ031.



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