Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 241002
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
402 AM MDT WED AUG 24 2016

.SHORT TERM...(Today and tonight)
Issued at 402 AM MDT Wed Aug 24 2016

Upper level trough will work slowly east across the state today,
although best lift will be pushing to our northeast by afternoon.
Water vapor and IR imagery show a deformation zone stretching out
across the forecast area early this morning and radar returns are
trying to increase on the plains as the downslope component has
finally weakened. The low levels are still quite dry per the
latest observations with the cloud deck ranging from 15-17
thousand feet MSL. Latest satellite data, short range model data,
and continued Q-G lift would support development of a few showers
on the plains. HRRR really gets excited but think that may be
overdone a bit and like the NAM/RAP projections given the still
dry and deep subcloud layer. Will have a chance of showers most
areas through the morning. In the mountains, snow level is
hovering near or just above 12 thousand feet. Precipitation
intensity has decreased so just a dusting to 1" possible over the
higher peaks yet this morning.

By afternoon, airmass will have the best chance of destabilizing
over the mountains where some clearing should first occur. Some of
the showers and storms that develop over the high country will
have a chance to drift southeast onto the nearby plains and I-25
corridor depending on amount of heating behind this morning`s
wave. But northeast corner of the state will be too stable to
support any redevelopment.

For tonight, convective activity should gradually decrease through
the evening as airmass stabilizes. There is a weak wave noted
however to our north, so a few showers and storms could linger til
close to midnight. Otherwise cloud cover should gradually break.
Highs today will be much cooler with the clouds and cooler air
aloft across the forecast area. Lows tonight will likely drop
into the upper 40s on the plains, with mostly 30s in the
mountains.

.LONG TERM...(Thursday through Tuesday)
Issued at 402 AM MDT Wed Aug 24 2016

Thursday through Friday...a weak and relatively moist
west/southwesterly flow aloft will be over eastern CO. An upper
level trough will be over srn ID/swrn WY Thursday morning will
move very slowly eastward with the trough axis over central CO by
Friday morning. Weak mid level QG ascent wl be over the cwa
through Friday morning along and east of the trough axis. The
trough axis is progged to move into eastern CO Friday aftn. NAM12
forecast CAPE values around 600-800 j/kg Thursday aftn and with
slightly more warming...close to 1000 j/kg for Friday aftn.
precipitable water values in the 0.80 to 0.90 inch range both
days. As a result...it will remain unsettled in spite of the
cooler temperatures. Overall...with go with sct coverage across
most of the cwa both days. Friday night...the main plume of
subtropical moisture is progged to shift east into NE/KS ahead of
the trough axis. For the weekend...it will be warmer with a drier
ams over western/northern CO...with the subtropical moisture more
over southern and eastern CO. As a result...wl lean towards these
areas with the highest pops. Some weak subsidence Saturday...then
another weak trough is progged to be near the Four Corners area on
Sunday which may provide some weak lift for tstms over the
mountains in the aftn/evng. A broad ridge is progged to stretch
across the swrn U.S. and into the central Rockies for early next
week...allowing for warmer temperatures and lesser pops across the
cwa for next week.

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 402 AM MDT Wed Aug 24 2016

VFR conditions will persist through Thursday morning. Main cloud
deck this morning should hover near 10 thousand feet AGL. Chance
of light rain showers with no visibility restriction can be
expected through 18Z. Then there is a 20-30% chance of convective
redevelopment by 21Z-22Z. That threat should be over by 03Z-04Z as
airmass stabilizes again with the loss of daytime heating. Winds
should turn more east/southeast through 18Z and increase to 10-15
knots. Then winds will turn back to normal drainage tonight
although weak Denver Cyclone could result in variable winds after
09Z.

&&

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

$$

SHORT TERM...Barjenbruch
LONG TERM...Cooper
AVIATION...Barjenbruch



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