Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 281143
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
543 AM MDT TUE JUN 28 2016

.SHORT TERM...(Today and tonight)
Issued at 345 AM MDT Tue Jun 28 2016

Main concern again today will be potential for severe storms
across the plains of Northeast Colorado. Currently, there is
still lingering storms over Eastern Phillips and Sedgwick county
but this activity will likely diminish by sunrise. 11/3.9
Satellite imagery showing some patchy low clouds and fog
developing over the plains given moist, low level flow and
dewpoints in the mid 50s to lower 60s. Will add patchy fog to
forecast for early this morning.

Broad ridge of high pressure remains over the region with center
across Utah and resultant moderate Northwest flow across the
plains of NE Colorado. The focus again today will be over the far
plains. Based on model forecasts...storms will initiate North of
Colorado in Eastern Wyoming and Nebraska and move Southeast across
the plains by late afternoon/evening hours. Surface based capes of
1500-2500j/kg will support large hail again today with good low
level moisture still in place. Tornado threat appears less but
can`t rule out a brief weak tornado.

Further West towards the urban corridor and Front Range airmass is
drier, despite dewpoints now in the mid 50s to lower 60s. This
moisture is rather shallow and expected to mix out this afternoon
with dewpoints in the 40s. With storms in this area...areal
coverage more isolated and expect main threat of gusty winds with
drier low levels. Should also see some isolated storms in the
mountains today as moisture levels have increased a bit more from
yesterday based on PW values from GJT 00z sounding. Temperatures
will be similar to yesterday`s readings.

.LONG TERM...(Wednesday through Monday)
Issued at 345 AM MDT Tue Jun 28 2016

On Wednesday, the upper level ridge of high pressure is centered
over New Mexico, with a weak west to northwest flow aloft over
Colorado. Some moisture caught up in the ridge, combined with
daytime heating will help produce scattered afternoon and evening
showers and thunderstorms, most numerous over the higher terrain.
The low level moisture seems to be limited, therefore the storms
should be high based with light rain and gusty winds.

On Thursday, the upper high shifts east into central Texas. The
circulation around the high allows subtropical moisture to move into
Colorado from the south and southwest. In addition, a weak cold
front will move across northeastern Colorado Thursday morning,
with increasing low level moisture behind it. GFS and NAM
soundings show PW`s in Denver at or above 1.30 inches by 00z
Friday. The combination of high moisture values, plenty of
instability (capes around 1000 j/kg) and upslope flow from the
surface to 700 mb should result in scattered to numerous afternoon
and evening thunderstorms across north central and northeastern
Colorado. Soundings also indicate a weak sfc-6 km mean wind which
should allow for slow moving storms and the possibility for
localized very heavy rain. Models show the best chance for heavy
rain from the foothills and adjacent plains south across the
Palmer Divide. Storms should decrease after midnight, possibly
lingering across far southeastern sections of the CWA through
early morning.


On Friday, the pattern looks similar to Thursday with the exception
that we lose the upslope flow. As a result, the storms should be
less numerous. However, there should still be plenty of moisture
around combined with daytime heating to produce another round of scattered
afternoon and evening showers and storms across the region. Some
of the storms could be strong and produce locally heavy rain and
some hail.

Warmer and drier weather is expected to return to the area over
the weekend as the upper high re-establishes over the southwestern
states and the subtropical flow of moisture into Colorado gets cut
off.

&&

.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 538 AM MDT Tue Jun 28 2016

Stratus and patchy fog have filled in over Norther Urban
corridor...mainly from Boulder Northward to Longmont and up to the
Wyoming Border. Another batch further East on the plains trying
to advect Westward. Feel there is enough threat to put in tempo
group for stratus into KDEN after 13z through 15z. Still
confidence is still on the low side. BJC is on the edge of the
stratus but think it will be in there temporarily for a few hours
this am. No other changes for late in the day with isolated
coverage of storms but no mention in TAF. Could be some outflow
gusty winds from nearby storms.


&&

.BOU Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...Entrekin
LONG TERM...Kalina
AVIATION...Entrekin


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