Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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792
FXUS65 KBOU 270118
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
718 PM MDT Mon Sep 26 2016

.UPDATE...
Issued at 718 PM MDT Mon Sep 26 2016

No changes planned. Clear skies and light winds will prevail.
Airmass is warmer than 24 hours ago, so lows will not be as cool
as last night.

&&

.SHORT TERM...(This evening through Tuesday)
Issued at 255 PM MDT Mon Sep 26 2016

Colorado is sandwiched in between storm systems with a strong and
deep trough over the northern Great Lakes and the short wave
trough just off the coast of Baja California well to our
southwest. The net result is a building ridge of high pressure
aloft bringing warm and dry conditions tonight through Tuesday.
Very little surface pressure gradient exists across the high
plains and so winds will remain light, even in the high country.
Very little cloud cover is expected through Tuesday. The remaining
question is temperatures for tonight and tomorrow. Even with
clear skies and dry air, do not expect temperatures to be as cool
as they were early this morning when Limon briefly dropped to 29
deg and other favored low-lying locations across the plains
dropped into the low to mid 30s briefly. Think that the warming
temperatures at low and mid levels (700 mb temps will be 4-5C
warmer Tuesday) will preclude the need for a frost advisory
tonight, and expect low temps a few degrees warmer than this
morning. High temps Tuesday will be 6-9 deg F warmer than Monday
area-wide, with most areas east of the mountains hitting 80
degrees.

.LONG TERM...(Tuesday night through Monday)
Issued at 255 PM MDT Mon Sep 26 2016

Colorado beneath a col region with a closed low hanging over the
nrn Gulf of California and a deep dynamic low pressure system
spiraling over the Great Lake States. Weak flow and warming
temperatures aloft with an upper ridge building over the Rockies
and nrn great Plains will thwart any opportunity for precip at
least through Wednesday night. Warm temperatures aloft and ample
sunshine will keep sfc temperatures several degrees above average
on Wednesday. On Thursday...models show the SW cut off low
reaching northeastward over Arizona and the circulation around
this cyclone drawing a long fetch of subtropical moisture up over
the Four Corner Region. Based on latest guidance could see some
of this moisture reaching the swrn fringe of the fcst area as
early as Wednesday night possibly resulting in a increase in cloud
cover. But its probably not until during the day on Thursday that
this moisture becomes deep enough and lapse rates steep enough to
generate showers and a few t-storms. Scattered showers will likely
begin first in the high country Thursday afternoon sprinkled with
a few thunderstorms. Show see all this spreading onto the plains
by afternoon and linger through the evening. Southwest flow should
keep temperatures on the warm side Thursday even with the gradual
increase in cloud cover. Max temps should still run 4-6 deg f
above average for the date. By Friday models show the closed low
lifting northeast as an open shortwave across the Four Corners by
afternoon and eventually over northeast Colorado by Saturday
morning. This should keep the weather unsettled around here with
increased clouds and low precip chances. Afternoon and evening
showers will be accompanied by isolated t-storms...although
precip amounts should be on the light side. Snow level may lower
enough for a dusting of snow on the high mtn ridges and peaks
Friday night. Models show a weak sfc cold front slipping down
along the Front Range late on Sunday...a bit later than what
earlier model runs had indicated. Do not see too much in the way
of cooling initially with this system. It`s on Monday when the
upper trough out west passes over the region when we`ll see the
better cooling...with temps back to near average. May also see a
few showers around on Monday mainly in the high country.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 718 PM MDT Mon Sep 26 2016

Mostly clear skies will prevail tonight and Tuesday. Normal
diurnal winds will prevail tonight with speeds around 10 knots or
less. For Tuesday, winds will remain light.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

UPDATE...Meier
SHORT TERM...Schlatter
LONG TERM...Baker
AVIATION...Meier



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