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Area forecast discussion 
National Weather Service Pueblo Colorado
601 PM MST Wednesday Mar 4 2015

Update...
issued at 550 PM MST Wednesday Mar 4 2015

Just a quick update to make minor adjustments to the forecast and
pull in the most recent observation. Mozley

&&

Short term...(this afternoon through thursday)
issued at 243 PM MST Wednesday Mar 4 2015

500-700mb trough axis swinging over southeastern Colorado at this time as per
latest rap...GOES satellite wind and acars data. Mountain top winds have
begun to swing around to a northwesterly component and Ridgetop temperatures have
begun to slip back. The final batch of middle-level moisture evident
on water vapor Sat imagery now passing over northern and central Colorado.
At low-levels east-southeasterly flow on the plains coupled with
a weakly unstable boundary layer continues to generate narrow bands
of light snow along and east of the sangre Delaware cristo ridge line.
Strongest radar reflectivities during the past few hours have been
confined the East Face of the Wet Mountains...the Spanish Peaks and
foothill areas from U.S. Highway 50 southward. Snowfall rates in
over and near this elevated terrain possibly in the 0.5 to 1 inch
per hour range. Radar also indicated elevated weak snow showers up
around the Colorado Springs/Rampart Range area. Cdot cams along
I-25 north of Colo spgs and west along U.S. 24 to Woodland Park were
indicating only wet roads and light snowfall. May see further
enhancement in all of these areas over the next 1-3 hours with
further enhancement in southeasterly/upslope flow on the plains. That said...
additional snow accumulations should be minor...perhaps no more
than an inch or two roughly above 6000 feet. For that reason...will
allow the Winter Weather Advisory expire at 2 PM MST for the southern
I-25 corridor zones 087..088..094 and 099 and hold onto the advisory
for the sangre Delaware cristo and Wet Mountain zones 072-075..079 and 080
until 4 PM.

Now for tonight...models continue to trend towards drier and
increasingly more stable conditions on the back side of the
exiting upper trough. Mesoscale models show light S-southeasterly low-
level flow on the plains gradually trending downslope during the
early evening hours. This should put an end to most of the
light snowfall over and near the mountains and south face of the Palmer
Divide on or before 03z and a clear out of low clouds in these
areas not long after that. Overnight...700-500mb mean layer flow
turns more north-northwesterly which further drier out the ambient atmosphere
and also Ushers in slightly warm aloft. Meanwhile low lying areas
along the Arkansas River between Pueblo and La Junta could patchy
fog form late tonight a a strong surface based inversion forms with
strong radiational cooling under clearing skies. Lows tonight again
quite cold with lows on the plains and mountain area anywhere from 8above
to 6 below zero. Same GOES for the San Luis valley.

On Thursday...a dry and stable northwest flow of moderate strength
should result in plenty of sunshine areawide and gusty northwesterly winds
over the higher mountain ridges. On the plains...light drainage winds
early go south-southeasterly by afternoon as they so often do with
solar heating of the east-southeast facing slopes. Highs on
Thursday...even with all of the sunshine and southerly breezes...
temperatures are likely to stay well below average. Average high
at Pueblo for the date is 55. Am going with a maximum temperature about 15
degree below that.

Long term...(thursday night through tuesday)
issued at 243 PM MST Wednesday Mar 4 2015

Finally will be looking at a drying and warming trend across much
of southern Colorado through at least middle of next week. May
even get above climate normals across southeast Colorado by early
by Tuesday and Wednesday. There will initially be a drier
northwest flow pattern which sets up from Friday through the
weekend as the high amplitude ridge remains across the West Coast.
With this flow pattern there appears to be a few weak ripples in
the flow with a weak frontal passage on Saturday. Across
southeast Colorado airmass too dry for any precipitation. However...mountains
may see a few snow showers on westerly facing slopes especially on
Sunday afternoon.

Stronger downslope flow develops over the region on Monday and
Tuesday when the Big Warm up begins. Temperatures expected to rise
into the upper 50s and even some 60s over southeast Colorado by
Monday and Tuesday. 700mb temperature rise to +2c on Tuesday and
around +4c by Wednesday.

Long range models are having more difficulty as time moves forward
into the middle of next week. Deep/dt of the GFS is showing a trend
of less ridging over Colorado to a stronger westerly flow regime
by next Wednesday. This faster flow is a result of a stronger long
wave trough that begins to carve out across the Pacific northwest
and northern rockies. Last nights 00z and 12z European were much
different and had much more ridging over Colorado so models seem
out of phase. Overall still warm and breezy on Wednesday.

&&

Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 243 PM MST Wednesday Mar 4 2015

Light snowfall and ils ceilings being reported at kcos could possibly linger
to around sunset as long as surface-5000 feet above ground level winds remain southeasterly.
Shift they reverse and turn northwesterly as some models indicate with the
strengthening northwesterly flow aloft...could see rather quick improvement
in these conditions. For now will hang onto the low clouds in the
kcos terminal forecast at least through early this evening. Otherwise...
clouds at kpub will gradually lift and clear rest of this afternoon
into the evening hours with set up of a light drainage flow
pattern. At kals...VFR conditions will prevail next 24 hours with
very light wind to calm conditions. On Thursday...light drainage
winds on the plains expected to go south-southeasterly by late
morning once the strong surface based inversion disperses. VFR conditions
will prevail. At the kals terminal expect clear/mostly clear
skies and light and variable winds on Thursday.



&&

Pub watches/warnings/advisories...
none.
&&

$$

Update...mozley
short term...Baker
long term...entrekin

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