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000 
FXUS65 KBOU 301014
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
414 AM MDT Thu Mar 30 2017

.SHORT TERM...(Today and tonight)
Issued at 415 AM MDT Thu Mar 30 2017

Upper high pressure ridge over Colorado early this morning but
will be shifting east into the central plains tonight. This 
movement in response to next Pacific storm system which will be 
dropping into the Great Basin through the short term period.  
Despite the ridge, moisture is already advecting into the the 
mountains and western colorado while stratus deck looms just east 
of the Colorado/Kansas border. May see some of this stratus slip a
bit westward into the far ne corner after sunrise. Warmer across 
the plains today with readings back up into the 60s. 

As the upper low moves closer to Colorado late today expect
increasing ascent as noted in layered QG fields for later this
afternoon and tonight. Given some weak instability expect showers
to develop in the mountains this afternoon and maybe even some
spilling out over the far northern plains tonight. Low level flow
will increase over the eastern plains from the southeast which
will import low level moisture and stratus later tonight. With
this flow expect a denver cyclone to also develop after midnight
tonight with possible stratus/fog over the Denver area and points
north to the Wyoming border. Expect higher coverage of showers 
near the Wyoming border as the southeast flow will create a better
chance of showers. Better chance of precip will develop during 
the day on Friday. 

.LONG TERM...(Friday through Wednesday)
Issued at 415 AM MDT Thu Mar 30 2017

Some differences remain in the long term with the initial system
Friday and Saturday, however they are coming to a slightly better
solution of the upper low position. As thought, the GFS and NAM
where the too fast and north outliers, and the 00z and now 06z
runs have been trending back toward the GFS ensemble mean, EC and
GEM. The upper low will be over northern Arizona Friday morning 
with southeasterly low level flow transporting moisture into the 
plains. Showers are expected to increase over the northern plains 
as well as the mountains as a jet moves north into the area and 
upward QG motion increases. Low level clouds are expected over 
most of the plains, however some clearing further south may allow 
for some thunderstorm development which may be transported into 
our area in the afternoon with strong forcing and shear. Upslope 
flow will be increasing with PWs around half an inch. Rain and
snow showers will be increasing across the plains, especially
along the foothills and up onto the eastern slopes of the Front
Range Mountains. Snow levels should start around 7500 feet that
morning, but then lowering through the day, to be down around 5500
by the evening. As the upper and surface low move into New Mexico,
winds will turn northerly through the night. A wet and slushy snow
is expected over the urban corridor and out over some of the
eastern plains, with some good potential snowfall rates overnight.
Have increased the forecasted snowfall for most of the area with
slightly better agreement, however differences in the position and
temperatures are still keeping the forecast confidence lower than
average. Best dynamics remain to the south of the forecast area as
well. Also, northerly winds play with the snowfall amounts over
the northern urban corridor with higher density if not all rain at
times. Forecasted low temps Friday night will be in the upper 20s
to lower 30s. 

Rain and snow, potentially heavy at times over the Palmer Divide
and southern Foothills, will continue into Saturday morning, with
the system pulling away in the afternoon. HIghs will likely peak
into the low 40s for the plains. Skies should clear that night
briefly but another shortwave trough will bring more cloud cover
and a slight chance of snow over the northern mountains Sunday. 

A system from the Pacific Northwest will push in quickly for
another round of precipitation Monday night into Tuesday, with
strong northerly winds expected Tuesday. It will be another tricky
rain/snow line forecast for the plains. 

Upper ridging is then forecast to build over the region for warmer
and drier weather Wednesday and Thursday with temperatures getting
back to near average for this time of year. 




&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 415 AM MDT Thu Mar 30 2017

Low level flow will shift southeast this afternoon and evening
which will eventually wind up into a Denver cyclone after midnight
tonight with potential stratus/fog moving into terminals after 09z
tonight. Could be some light showers late aftn/evening with some
increase in moisture, lift and marginal instability.   

&&

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

$$

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