245 
FXUS65 KBOU 301035
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
435 AM MDT Mon Apr 30 2018

.SHORT TERM...(Today and tonight)
Issued at 430 AM MDT Mon Apr 30 2018

Forecast area remains under a broad swly diffluent flow aloft 
in advance of a deepening mid-level trough slowly migrating 
eastward over the Intermountain Region. 06z Model run has the 
500mb trough axis passing over the Salt lake City area around 
18z today and convective precip forming over the northwest 
corner of Colorado about that time. Through the day should see 
the flow aloft strengthen and so will swly surface winds on the
plains with pressure falls on the plains. Strongest sfc winds on
the plains roughly southeast of a Parker to Sterling line and
centered around Limon in Lincoln County by mid-afternoon.
Prevailing speeds across this portion of the CWA expected to be in
the 15-25 mph range by midday, with peak gusts in the 25-40 mph 
range across ern Elbert, Lincoln, eastern portions of Adams and
Arapahoe and southern Washington Counties this afternoon. The 
strong gusty winds and RH values in the 7 to 12 percent range 
will likely result in patchy to areas of blowing dust in this 
same area. Therefore, will add this to today's forecast. This  
same area is presently under a RED FLAG WARNING starting at 10 AM
MDT this morning and ending at 7 PM MDT this evening. It's
possible the waning could be extended another hour or hour for
Lincoln County should the gusty swly winds continue, but will 
hold off for now.

Otherwise, as the upper trough and cold pool aloft moves closer to
the forecast area, should see an increase in clouds initially over
the high country and later today out over the plains. Should also
see the formation of isolated to scattered showers/t-storms in the 
northern mtns by around midday as moisture increases and mid-
level temperatures cool. By late afternoon, shower/t-storm
coverage should expand southward over remaining mtn areas with
passage of a weak shortwave disturbance. For the plains, HiRes  
models indicate a narrow band of convection, i.e., t-storms
forming along a sw-nw convergence zone lying across Morgan and
Logan Counties around 00z/Tue. And as the shortwave passes should
see convection initiation. Gusty winds and lightning probably main
product of these short-lived storm cells. See this convection
going away before midnight as it shifts up in to Sedgwick and
Phillips Counties. otherwise it should remain dry elsewhere on the
plains under late tonight with a weak push of cooling, more humid 
slips down from sern WY and wrn NE. With a shift to n-nely bndry
layer winds, could see low and mid-level clouds form along the 
Front range as well as a few sprinkles. Do not see as fog at this
time, but wouldn't rule it out around dawn.  


.LONG TERM...(Tuesday through Sunday)
Issued at 430 AM MDT Mon Apr 30 2018

The middle of the week will be trending cooler and wetter across 
much of Northern Colorado as upper low over the southern Great
Basin impacts the region. On Tuesday, Northeast Colorado will be
in a post frontal regime with shallow upslope flow and gradual
moistening of the airmass. PW values are forecast to increase to
.50-.75" over the plains by later Tuesday afternoon. Only marginal
instability will result, given the cool low levels of the
atmosphere, so mainly rains showers and possibly an embedded, yet 
non- severe thunderstorms. 

The closed low circulation will begin to lift out and move
northeast across Colorado in the Wednesday through early Thursday
time frame. This will increase widespread ascent aloft coupled 
with 100+kt jet streak streaming across Colorado. Given the track 
of the low across the central and northern portions of the state, 
the best chance of precipitation will be over Northern Colorado, 
mainly north of the Interstate 70 corridor and lesser chances 
further south. Expect decreasing showers by Thursday night as the 
low moves out onto the central plains with drying and subsident 
airmass taking over across Colorado. 

Model forecast qpf is fairly substantial from the GFS/European 
with a broad 1-2 inches of water from Denver northward to the 
northern border areas with lesser amounts further south. The NAM 
amounts have the heaviest qpf further north towards our border 
areas with Wyoming. This system will be fairly warm with all rain 
at lower elevations and snow levels ranging from 8000-9500 feet on
Wednesday before lowering a bit more on Thursday. The best chance
of accumulating snow in the mountains would be on Wednesday night
and Thursday as flow turns northwest along with cold air
advection. 

High pressure ridge aloft will build over the region on Friday and
Saturday with warmer temperatures and only a slight chance of
showers over the mountains. 

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 430 AM MDT Mon Apr 30 2018

VFR conditions today with s-swly winds light early this morning,
then increasing to 10-20kts by midday. Stronger winds expected at
KAPA and KDEN this afternoon with possible gusts to 30kts. May
even some blowing dust for a time with the gusty winds and low 
relative humidity. Tonight, winds will diminish as remain
southerly until a shift to the north-northeast around 09z with the
passage of a weak cold front. Could see scattered to broken 
clouds flow around dawn with ceilings possibly as low as 6000 ft
agl. Not expecting any precip with this surge, although foothills
areas could see sprinkles or drizzle. 

&&

.FIRE WEATHER...
Issued at 430 AM MDT Mon Apr 30 2018

Expect another windy and warm day today with wind speeds of 15 to
25 mph with gusts in the 30 to 40 mph range across eastern 
portions of Adams and Arapahoe Counties, and eastern Elbert, 
Lincoln and Washington Counties this afternoon. It appears the 
southern foothills in Jefferson and Douglas Counties will also 
blow today, and with low humidities, this area will also be
included in the Red Flag Warning in effect for the counties 
mentioned above. Expect minimum relative humidities in the 7-15 
percent range, even though temperatures will be slightly cooler 
today. The RED FLAG WARNING will run from 10 AM to 7 PM MDT today.  

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 10 AM this morning to 7 PM MDT this 
evening for COZ216-245>247-249.

&&

$$

SHORT TERM...Baker
LONG TERM...Entrekin
AVIATION...Baker
FIRE WEATHER...Baker