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FXUS65 KBOU 180350

Area Forecast Discussion
National Weather Service Denver/Boulder CO
850 PM MST Sun Nov 17 2019

Issued at 845 PM MST Sun Nov 17 2019

Mid-level moisture streaming in on northwest flow will continue to
bring increased clouds across the region into the morning hours.
model soundings show an inversion around 700 mb that could enhance
some mountain wave clouds for the morning hours with increased
winds over the higher terrain. Still maintain a slight chance of
light snow showers across the northern mountains north of I-70
with the moisture and weak lift provided by the accompanying
shortwave. Subsidence behind this feature will allow for clearing
and warming conditions into Monday. Current temperature
projections look good. 


.SHORT TERM...(This evening through Monday)
Issued at 141 PM MST Sun Nov 17 2019

High clouds will move across northern Colorado tonight ahead of a
shortwave that will pass north of us late tonight. There's not
much mid level moisture upstream but the model idea of a little
band near the trough axis looks right, and this would give a
slight chance of a little snow over the northern mountains for a
few hours late tonight. This will also be the period with the
greatest threat of wave amplification as the mid level flow
increases a bit, but it doesn't look like winds over 50 mph should
get down below timberline. There should be rapid clearing behind
the shortwave, though there may still be a few wave clouds. After
that, the gradual warming continues with winds coming down a bit
in the mountains as the mid level winds diminish. Forecast highs
for Monday look good.

.LONG TERM...(Monday night through Sunday)
Issued at 306 PM MST Sun Nov 17 2019

Upper ridging will cover the CWA Tuesday. West-southwesterly flow
aloft is in place Tuesday night through Wednesday night. At 12Z 
Thursday morning, models have a pretty strong upper closed low 
centered around the southern Great Basin. There is weak upward 
synoptic scale energy progged for the forecast area Monday night 
through Wednesday night; all five periods. The best looking 
dynamics with the system are south of the CWA Wednesday night. 
The low level winds look to be normal diurnal wind patterns, but a
bit on the weak side. The low level wind and pressure fields show
a strong cold front move across the CWA Wednesday morning. 
Upslope, north-northeasterlies are in place all of Wednesday and 
Wednesday night. For moisture, it is pretty dry Monday night into 
early Wednesday morning. Certainly much more so than the previous 
models/GFE grids indicated. Moisture increases significantly 
Wednesday morning. There is even some in the lower levels after 
the cold front moves down. Moisture is pretty deep for most of the
CWA Wednesday mid-morning through Wednesday evening. It decreases
a bit overnight Wednesday. The moisture, dynamics and upslope 
warrant pretty decent pops on Wednesday and much of Wednesday 
night. A significant snowfall doesn't look good at this time. For
temperatures, Tuesday's highs will be 3-5 C warmer than Monday's.
Wednesday's highs are 9-16 C colder than Tuesday's readings.  For
the later days, Thursday through next Sunday, models have an 
upper closed low weakening and over the four corners by 12Z 
Friday morning. By Friday afternoon, the various models show that 
feature to be located anywhere from northern Arizona to 
southeastern Kansas; very poor agreement. By Saturday, there is 
upper ridging over the CWA on the GFS with northerly flow aloft 
and a weak upper closed low over Colorado on the ECMWF. This poor
agreement between the two continues on Sunday, with an upper 
ridge on the GFS and northwesterly aloft on the ECMWF.  Moisture 
and upslope is progged in place Thursday, with the GFS drying out
on Friday. The ECMWF keeps some moisture around into Saturday,
then dries out Sunday.  The GFS is dry both Saturday and Sunday. 


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 845 PM MST Sun Nov 17 2019

VFR conditions are expected through the period. Drainage winds
will dominate through 10z where they will turn more westerly with
speeds staying under 10 kts. By the afternoon a northerly winds
will bring some speeds from 10-15 kts with a mid-level bkn deck
through most of the day. 




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