Area Forecast Discussion
Issued by NWS Pueblo, CO

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FXUS65 KPUB 111716

Area Forecast Discussion
National Weather Service Pueblo CO
1116 AM MDT Mon Jun 11 2018

.SHORT TERM...(Today and tonight)
Issued at 414 AM MDT Mon Jun 11 2018

Currently...A progressive, negatively tilted mid-level trough
passing well to the north of Colorado per GOES-16 water vapor
imagery has sent a surface cold front down the eastern Colorado
plains early this morning. Radar reflectivity imagery shows this
front has already made it into the southern tier of eastern Colorado
counties. Surface obs confirm winds behind the front are gusting to
around 30 mph from the north. The front has had little effect on the
diurnal temperature trend. Skies are clear over most of the forecast

Today...In the mid/upper levels, flat westerly flow will dominate
the pattern as a ridge builds south of Colorado. Associated QG
subsidence will help keep skies clear and the forecast area dry. At
the surface, the cold front will continue south into New Mexico in
the next hour or so. Winds across the plains will remain gusty from
the north through about mid morning. Thereafter, they will remain
breezy and shift to an easterly/southeasterly direction. Deep
vertical mixing will lower RH values to critical levels by early
afternoon along the I-25 corridor and areas just to the east, but
the southeasterly surface winds will draw atmospheric moisture back
across the plains during the late afternoon/evening. Winds will also
reach borderline critical fire weather levels across the plains by
late afternoon. Although the low RH and gusty winds may create areas
of critical fire weather conditions by early evening along the I-25
corridor south of Pueblo, conditions shouldn`t last long enough to
warrant a highlight. Winds won`t increase to critical levels until
late in the day, at which time RH values will begin to increase.
Temperatures across the plains will be cooler than on previous days,
but highs will still be above average, with upper 80s to low 90s in
the forecast. Highs across the high valleys will remain in the mid

Tonight...Wind speeds will relax by midnight and become easterly for
the rest of the evening. Temperatures will not be much different
than during previous evenings, with lows in the mid to upper 50s
across the plains and low 40s in the high valleys. The forecast area
will remain dry with mainly clear skies.

According to the HRRR-Smoke model, considerable smoke from the 416
wildfire near Durango will again make it into the San Luis Valley.
This smoke may reduce visibility slightly, so have added areas of
smoke to the grids from mid afternoon through midnight. Line

.LONG TERM...(Tuesday through Sunday)
Issued at 414 AM MDT Mon Jun 11 2018

.Tuesday...Low level moisture returns to the eastern plains.
Believe the NAM may be too zealous with CAPE and prefer the GFS
solution. GFS has dew points on the lower 50s on the plains with
CAPE values around 15000 J/kg. With 30 to 40 knots of bulk shear,
severe storms are possible in the later afternoon and evening. SPC
has a slight risk for much of the eastern plains. The marginal
risk extends westward to much of the I-25 corridor, which is
reasonable given the models keep the better low level moisture
east of this region. Middle and upper levels of the atmosphere
remain dry so lower chances for any storms over the mountains.

.Wednesday through Friday...Upper high develops over New Mexico
and moves into Texas as a trough moves into the Great Basin. Deep
southwest flow develops over the region. Normally in mid June
there would not be much moisture in the southwest flow as the SW
monsoon has not developed. However, the southwest flow will likely
bring some moisture from hurricane Bud into Colorado. Expect a
gradual increase in middle and upper level moisture each day. The
presence of weak, difficult to forecast, disturbances in the
southwest flow will influence the amount of convection. Further
east, weak lee trough will be present over the plains. Southerly
flow on the high plains will continue moving moisture northward
from the Gulf of Mexico with some of this moisture meandering onto
the eastern plains. This should at least keep humidities higher
on the plains and also allow for some storms to develop in the
afternoon and evening.

.Saturday and Sunday...Fetch of middle and upper level moisture
will likely continue as a trough remains somewhere in the Great
Basin. In addition, the EC and GFS show a cold frontal passage
around Saturday evening with upslope flow developing. Looks like
there will be plenty of low level moisture to advect westward on
Sunday, and there is the potential for some widespread beneficial
rainfall. The devil is in the details which cannot be determined
this far in advance, but it is looking optimistic for some
rainfall sometime over the weekend or early next week.


.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1115 AM MDT Mon Jun 11 2018

VFR conditions are expected at COS, PUB and ALS over the next 24
hours. Breezy east to southeast winds 15-20kts are expected at COS
and PUB this afternoon, as low level upslope flow develops and
deepens behind this mornings dry cold front with a more diurnal
wind regime expected tonight and again tomorrow. A mainly diurnal
wind regime is also expected at ALS through the period.




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