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000 
FXUS65 KPUB 260958
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
358 AM MDT Wed Apr 26 2017

.SHORT TERM...(Today and tonight)
Issued at 340 AM MDT Wed Apr 26 2017

Currently...radar indicates light precipitation is rapidly 
decreasing in coverage over the Eastern Plains from north to south. 
Snow levels have been running around 6 kft near Trinidad with only 
minor accumulations expected through sunrise over the southern 
Sangre de Cristo range.  Model guidance has precipitation shifting 
south into New Mexico by 8 to 9 am.  Elsewhere, northerly winds have 
brought cool morning temperatures with most of the Plains in the mid 
30s to near 40 degrees.

Today and Tonight...the upper system that brought yesterdays 
precipitation to the area will continue southeast into Texas, while 
the next upper disturbance in the northwest flow aloft moves into 
the area by tonight.  Once the light precipitation near the New 
Mexico border clears to the south this morning, expect generally dry 
conditions to prevail across the Plains through this evening.  Over 
the mountains, expect snowfall to increase along the Continental 
Divide by this afternoon, with periods of moderate snowfall through 
tonight over the Central Mountains.  Snow accumulations of 1 to 4 
inches are possible through Thursday morning over the Central 
Mountains.  Precipitation is forecast to spread east into the 
Eastern Mountains and Palmer Divide region later tonight, with an 
inch or two of snow possible on areas peaks.

Several of the high-res model solutions do develop isolated showers 
this afternoon over the Eastern Mountains, and spread them east into 
the I-25 corridor through this evening.  Given the inconsistencies 
from run to run and that not all models are showing this, did not 
spread pops east into the I-25 corridor for this afternoon and 
evening.  If they do develop, the showers will produce spotty light 
rain.

Temperatures today will be on the cooler side with mid to upper 50s 
for highs across most of the lower elevations.  Lows tonight will 
fall into the upper 30s to lower 40s.  Mozley

.LONG TERM...(Thursday through Tuesday)
Issued at 340 AM MDT Wed Apr 26 2017

...Potent Storm possible for Friday night-Saturday for southern 
CO...

Upper trof shifts eastward on Thursday with strong winds and snow
continuing across the central mountains through at least the 
morning. Drier air and downward forcing spreads in during the 
afternoon...however soundings are showing sufficient residual 
moisture and instability for snow showers to continue into the 
afternoon. Winter Weather Advisory will carry through until 00z 
Fri but suspect precipitation will be on the decline across the
central mountains by late afternoon. Meanwhile...cold front will 
drop through the southeast plains Thursday afternoon and will 
become the focus for scattered afternoon showers and 
thunderstorms. 

Thursday night could see pockets of freezing temperatures along the 
I-25 corridor though its not clear just how widespread this will be 
given that westerly winds may help to keep temperatures up a bit. 
May end up being a brief period of freezing temperatures towards 
sunrise if winds decouple for long enough.  

All attention then turns to the next storm system which models are 
in remarkable agreement on for Friday-Saturday.  All are painting a 
heavy precipitation event for southern CO with temperatures cold 
enough Friday night/Saturday morning for a change over to snow 
across the plains as well.  Energy digging along the western fringe 
of the broad trof positioned across the western U.S. closes off an 
upper low over the 4 corners region by Friday evening.  This system 
then drops southeastward into northern/central NM through Saturday 
morning then lifts back northeastward into the TX/OK panhandles into 
western KS by Saturday evening.  This is a prime track for southern 
CO to get widespread precipitation.  Friday will still be relatively 
mild ahead of the storm...but should see deteriorating conditions 
from north to south late Friday afternoon through Friday night. 
Models show some decent cold air with this system...with a change 
over to snow along the Palmer divide between by 03z spreading down 
into the COS area by 06z...with a change over to snow across all 
of the southern I-25 corridor and southeast plains by 12z-15z Sat.
Best forcing appears to be between 06z through 18z Saturday as 
area comes under strong difluence aloft. H7 winds in both NAM and 
GFS become E then NE at 30-40 kts providing strong upslope flow
for the southeast mountains as well. And with H7 temperatures 
dropping to between -8 and -11C by Saturday morning...this would 
support a switch over to snow across all of the plains by Saturday
morning. Given the latest trends towards a stronger system have 
increased pops across southern CO through this period. Cooled off
max temps for Sat a few degrees as well.  Hardest hit should be 
the southeast mountains and I-25 corridor. Impacts across the 
southeast plains will be determined by the timing of the switch 
over to snow and snowfall rates as the ground is carrying some 
residual heat. Winter weather highlights will likely become 
necessary for portions or all of southern CO Friday night through 
Saturday evening if forecast models stay consistent so stay 
tuned. Its still too early to pin down snowfall amounts just yet 
but confidence is increasing that this could be a high impact 
event for the mountains and adjacent plains. 

System pulls away from the area Saturday night with drier weather 
spreading in for Sunday.  Will have to watch for freezing 
temperatures again Sunday night.  Weather remains fairly quiet 
through Monday...though central mountains will see periodic 
showers in NW flow. Another storm system will be looming on the 
horizon for Tuesday/Wednesday. -KT

&&

.AVIATION...(For the 12Z TAFS through 12Z Thursday morning)
Issued at 340 AM MDT Wed Apr 26 2017

VFR conditions at all three terminals through this afternoon.  An 
upper disturbance will bring an increase in mid and high clouds for 
late this afternoon and tonight.  KALS may see light rain or snow 
towards Thursday morning.  There is a very low possibility of a 
shower or two near KCOS and KPUB this afternoon, but confidence is 
not high enough to include in the 12z TAF. Mozley

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 PM this evening to 6 PM MDT 
Thursday for COZ058-060.

&&

$$

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