Scientific Forecaster Discussion
fxus65 kpub 191817
Area forecast discussion
National Weather Service Pueblo Colorado
1117 am MST Tue Nov 19 2019
Short term...(today and tonight)
issued at 403 am MST Tue Nov 19 2019
Flow aloft increases from the southwest over Colorado today as the
kicker system drops through northern and central CA, filling and
ejecting the upper low off the coast of the Baja Peninsula. Should
see gradually increasing mid/high level wave cloudiness today as
Pacific moisture starts to increase. Lee trough deepens in
response to increasing southwest flow aloft but stays pinned up
along the I-25 corridor. This will keep breezy westerly winds
along and west of I- 25 for the most part, with southeasterly
winds across the plains to the east. With the increase in wave
cloudiness and lack of stronger winds across the plains, guidance
temperatures are curiously cool across the plains, and may not be
so far fetched given less mixing. Hrrr seems to agree with keeping
temperatures around 70 or a little cooler along the eastern
Arkansas River valley and points northward. Temperatures should
warm into the lower 70s along the southern I-25 corridor. Overall
did go a little warmer than guidance across the southeast plains,
as temperatures yesterday overachieved compared to guidance and
model blends. But in general readings may end up pretty similar to
yesterday. Temperatures out west should also be similar to those
Moisture increases tonight along the Continental Divide with the
approach of the upper wave, so should see snow showers spread into
western areas towards midnight and get heavier by Wednesday morning.
An inch or two will be possible across the eastern San Juans by
morning given favorable orographics...with additional snow expected
to fall through the longer ranges as showers spread eastward. -Kt
Long term...(wednesday through monday)
issued at 403 am MST Tue Nov 19 2019
On Wed, a disturbance over Arizona moves northeastward across co,
bringing increased chances for precip across most of southern co,
although the I-25 corridor, mtns, and high valleys should see the
highest chances for precip. Temps will be several degrees cooler on
Wed, with highs mostly in the 50s to lower 60s over the plains, and
in the mid 40s to around 50 in the high valleys, thus any precip in
these areas will be rain, while the high elevations will be cold
enough for snow.
Wed night that disturbance moves out of the area, while an upper low
is forecast to move over the southern tip of Nevada or southwest Utah
depending on which model you look at. Ahead of this low, moisture
streams into western Colorado with snow over the mtns and and high
valleys. Low level upslope flow over eastern co, is expected to
bring some light snow along the I-25 corridor, while the southeast
plains should see little chance for precip Wed night.
The European model (ecmwf) continues to be slower than the GFS moving the low toward
Colorado. However, on Thu the mtns and high valleys should continue to
have high chances for snow, and by late afternoon/early evening, the
models agree in moving a band of precip over the far southeast
plains as well. Temps on Thu will be even cooler, with highs only
in the 30s to around 40 over southeast co, with upper 30s to lower
40s in the high valleys.
Thu night, the models bring the upper low over Colorado and then move it
east over Kansas on Fri. There will be chances for snow across most of
southern Colorado Thu night, although accumulations look like, and
then precip chances will decrease on Fri.
As far as winter weather highlights go...the Winter Storm Warning
for the southwest mtns looks good, and will go ahead and issue a
winter wx advisory for the central mtns from early Wed morning
through Thu night. Will probably end up needing an advisory for the
Sangre de Cristo mtns for Thu and into Thu night, but will hold off
issuing anything at this point.
Dry weather is then expected Fri night through sun, and then the
next weather system may move bring precip to the area on Mon.
Aviation...(for the 18z tafs through 18z Wednesday afternoon)
issued at 1111 am MST Tue Nov 19 2019
Today - tonight...VFR. Just have some passing high clouds across
the region, ahead of the next weather maker. Winds are and will
remain generally light out of the south. High confidence.
Wednesday...mostly VFR. A little more uncertainty at kals if
rain/snow showers make it to the terminal by the end of this
period which may bring ceilings down to MVFR levels. At this time
confidence is on the lower side of MVFR impacts so we refrain from
mentioning them at this time. Elsewhere, VFR conditions will
prevail as ceilings begin to thicken and lower with time tomorrow
ahead of the next weather system. High confidence outside of kals.
Winter Storm Warning from 11 PM this evening to 11 PM MST
Thursday for coz066-068.
Winter Weather Advisory from 6 am Wednesday to 5 am MST Friday