Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 290343
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
943 PM MDT SUN AUG 28 2016

.UPDATE...
Issued at 936 PM MDT Sun Aug 28 2016

Plains convection has shifted northeast on outflows and is running
away from both upper and low level support. Expect this area to
continue to diminish over the next few hours. Meanwhile area of
fairly steady rain has developed over Park county with stronger
thunderstorms south of Colorado Springs. Support for this will
likely also be shifting southward. Upper features moving slowly
but low level outflow will likely shift the stronger convection
more quickly in an hour or two. Still, this means steady rain over
Park county for a while, and the edge of the plains convection
could meander into southern Lincoln county for a while. We will be
making adjustments for these trends. Otherwise the forecast is
looking pretty good. Lows around Denver may be a few degrees
cooler as the clouds thin over the rain cooled air.

&&

.SHORT TERM...(This evening through Monday)
Issued at 300 PM MDT Sun Aug 28 2016

An upper low spinning over the Four Corners area continues to
bring lift and moisture to the region. As a result, scattered
thunderstorms are moving slowly north to northwest over the high
terrain as well as the Palmer Divide and northeastern plains.
Activity will be more isolated in nature over the northern urban
corridor. Winds turning upslope up to 700 mb and divergence aloft
will allow for scattered to numerous storms over the Front Range
mountains and foothills into the early evening. Higher CAPE
values over the eastern plains will allow for scattered storm
with brief heavy rain, small hail with such high freezing levels
and some gusty outflow winds. With the upper low moving closer and
a jet speed max putting the area in the favored left exit region,
hard to argue against the models showing some showers and storms
continuing into the evening and overnight, favoring areas south
of I70.

The upper low will slowly move over southern Colorado Monday, cooler
air aloft and cloud cover will allow for temperatures to be a
several degrees cooler than today. Expect another day of scattered
showers and thunderstorms producing brief heavy rain as easterly
flow deepens, perhaps slightly bigger hail with lower freezing
levels and gusty outflow winds. The stronger storms will likely be
found over the east central plains where CAPE will be larger, with
another day of north-northwesterly movement of the storms.

.LONG TERM...(Monday night through Sunday)
Issued at 300 PM MDT Sun Aug 28 2016

Upper level trough just to our south will gradually shear out and
weaken Monday night through Tuesday. Then an upper level ridge
will build to our north late Tuesday into Thursday. By week`s end,
the upper level ridge is expected to shift east into the Midwest
with increasing west/southwest flow aloft across Colorado.

For Monday night, the better moisture and weak Q-G lift associated
with the trough is still located from central and southern
Colorado into the Palmer Divide area and then eastward onto the
plains. Therefore, will continue to keep the PoPs highest in those
locations with lower chances farther north to the Wyoming border.
A few showers and storms could once again linger through the night
on the eastern plains.

Tuesday through Wednesday, the upper level ridge will begin to
build over the top of the weakening trough. This may result in a
decrease in storm coverage, with the main threat shifting slightly
farther south. Points near the Wyoming border may stay completely
dry with a drier and more stable airmass there.

By Thursday and Friday, the flow aloft will turn more
west/southwesterly as an unseasonably deep upper level trough digs
into the Pacific Northwest. This would bring warmer and drier
downslope flow to the plains, while the mountains will continue
to see a chance of showers and thunderstorms each afternoon and
evening. There may be a weak front on the plains toward Saturday
or Sunday, but overall expect above normal temperatures and just a
slight chance of afternoon and evening storms.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 936 PM MDT Sun Aug 28 2016

VFR conditions expected through Monday. Easterly winds should
become southerly around 06z. Scattered thunderstorms are expected
again late Monday afternoon, with the main impact variable
outflow winds gusting to 30 knots.

&&

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

$$

UPDATE...Gimmestad
SHORT TERM...Kriederman
LONG TERM...Barjenbruch
AVIATION...Gimmestad



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