Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus65 kbou 181708 
afdbou

Area forecast discussion
National Weather Service Denver/Boulder Colorado
1008 am MST Mon Feb 18 2019

Update...
issued at 957 am MST Mon Feb 18 2019

Light snow has diminished over most of the area with clearing
across the high country and portions of the southern County Warning Area. This
drying push is seen on satellite and will continue over the next
few hours before moisture moving around the cyclone will bring
mid level clouds. Low level stratus is seen over the northern
portions of the region near the Wyoming border where some light
snow continues with winds pushing up against the northern
foothills. With continued moderate southeast winds and stratus along the
base of the foothills some light flurries may continue through the
afternoon across areas mainly west of I-25. Still tracking the
next incoming system that is starting to push into western Colorado.
Will make adjustments to pops for the high terrain and eastern
plains east of a Limon to Akron line as decent lift will bring
snow to the area overnight into Tuesday.

&&

Short term...(today and tonight)
issued at 509 am MST Mon Feb 18 2019

Weak shortwave rotating away from the main upper low over northern
Arizona is bringing lift across eastern Colorado this morning. The
northern edge of the steady snow is around Denver, and this should
diminish as the lift moves away by mid to late morning. The cold
low level air will remain in place though with a pretty good
stratus deck, so there may still be a few flurries. I did warm
temperatures a little in the mountains this afternoon as there
should be some sun there. The warmest temperatures today could be
over the higher mountains.

The next shortwave will shift the trough axis toward US tonight
and bring another area of lift that looks pretty similar to the
current wave. There could be a bit more lift, but also more
focused over the southern and eastern parts of our area. The
result should be similar, with pretty good coverage of light snow,
possibly a few hours of better accumulating snow and again mainly
south and east of Denver. We bumped up the pops and amounts a
little. We'll need to look at the stronger lift along our eastern
border for a possible advisory for later tonight.

Long term...(tuesday through sunday)
issued at 509 am MST Mon Feb 18 2019

Models have south-southwesterly flow aloft over the County Warning Area on
Tuesday, then weaker southwesterly flow aloft for much of Tuesday
night. An upper trough axis moves across the County Warning Area Tuesday night
into Wednesday morning. There is weak westerly flow aloft as a
weak upper ridge moves across the area the rest of Wednesday and
Wednesday evening. Strong southwesterly flow aloft is in place
later Wednesday night with another trough developing into the
Great Basin. The qg Omega fields keeps upward vertical velocity
over the County Warning Area through Tuesday evening. Subsidence moves in after
that continuing all of Wednesday. Upward synoptic scale energy
returns Wednesday night. It is fairly weak however. On Tuesday and
Tuesday evening, the low level winds are mainly southeasterly
over the plains so a Denver cyclone is a good bet. Localized
northeasterly upslope over the western Denver Metro area could
mean slightly better chances of snow there. By 12z Wednesday
morning, drainage winds are in place. Downsloping winds prevail on
Wednesday and Wednesday evening, with more drainage patterns
overnight. For moisture, there is plenty around Tuesday and
Tuesday night, with a partial decrease noted on Wednesday and
Wednesday night. The quantitative precipitation forecast fields have some limited measurable
snowfall over most of the County Warning Area Tuesday and Tuesday evening. There
is areas of light snow accumulations indicated over the high
mountains Wednesday and Wednesday evening, then nothing after
midnight. For pops, with go with 30-60%s Tuesday through Tuesday
evening for all the County Warning Area. After that, will go with 10-30%s in the
mountains only through Wednesday night. Again, the snow will
mainly be light with a pretty cold airmass in place. Accumulations
will not be significant. For temperatures, tuesday's highs will
only be a tad warmer than today's highs. Wednesday's highs will
warm up 3-8 c from tuesday's readings. For the later days,
Thursday through Sunday, models carve out another mean trough to
the immediate west for Colorado Thursday into Saturday. There is
pretty strong southwesterly flow aloft for the County Warning Area during that
time period. The upper trough axis pushes eastward across Colorado
on Saturday and there is zonal flow over Colorado on Sunday.
There will be moisture available Thursday afternoon through
Saturday afternoon for some more snow in many areas. The rest of
the weekend is drier with just minor pops for snow in the high
mountains. Temperatures stay below seasonal normals through
Saturday, with near normal readings on Sunday.

&&

Aviation...(for the 18z tafs through 18z Tuesday afternoon)
issued at 957 am MST Mon Feb 18 2019

Slight scattering our with drying from the south, but expect mid
level deck to return with ils conditions after 19z. Light snow
will return with MVFR possible this evening and continue overnight
into the morning push on Tuesday. Main area of intense snow is
expected to be further east of area terminals, however some
reduced vis is possible after 10z Tuesday with snow. Currently, a
Denver cyclone is impacting the region with winds expected to stay
out of the east, transitioning to the southeast over the next few hours
with speeds from 10 to 15kts for den. Depending on where the
cyclone tracks, winds could switch to a more southerly or southeast
direction later in the taf period for area airports.

&&

Bou watches/warnings/advisories...
none.
&&

$$

National Weather Service Glossary of Abbreviations