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000 
FXUS65 KPUB 122245
AFDPUB

Area Forecast Discussion
National Weather Service Pueblo CO
345 PM MST Thu Dec 12 2019

.SHORT TERM...(This evening through Friday)
Issued at 345 PM MST Thu Dec 12 2019

Leading edge of the upper level jet pushing into Colorado 
this afternoon, bringing some very light snow to the central 
mountains from Cottonwood Pass northward. Jet and associated 
moisture will continue to plow into the state overnight and through 
the day on Fri, leading to a gradual ramp up of snow intensity and 
coverage along the Continental Divide. Snow accumulations through 
Friday afternoon won't be too extreme (5-10 inches over the Sawatch 
and Mosquito Ranges), but with strong west winds producing 
widespread blowing snow, especially near/above timberline, winter 
storm warning looks warranted for higher mountain zones, with 
advisory for lower elevations of Lake County. Farther south along 
the Divide, snow looks much lighter, with just a few inches expected 
over the La Garitas/San Juans. Some mainly light spillover showers 
expected in upper Arkansas Valley and over the eastern mountains, 
through Friday, while plains and bulk of the San Luis Valley stay 
dry and fairly mild under westerly flow aloft.

.LONG TERM...(Friday night through Thursday)
Issued at 345 PM MST Thu Dec 12 2019

Active meteorological conditions are expected over the CWA from 
Friday night into Monday morning in advance of improving conditions
from later Monday into next Thursday.

Initially, snow, heavy at times(with incoming system/PV 
analysis/etc.)in combination with gusty winds will be ongoing over
the Central Mountains Friday evening, with snow expanding into 
the majority of our Continental Divide locations into Saturday 
night and then continuing into Sunday, therefore have expanded 
inherited Winter Storm Watch to also include the La Garita 
Mountains in addition to the eastern San Juan mountains from late 
Saturday afternoon into Sunday afternoon. 

Elsewhere, locations east of the I-25 corridor should experience
generally dry and cooler conditions in combination with gusty 
winds at times from Friday evening into Saturday evening(with 
encroaching showers possible from the west as Saturday 
progresses). 

Recent longer range computer simulations, ensembles, PV analysis, 
forecast model soundings/etc. still indicate that the highest 
potential for more widespread and possibly moderate to heavy 
precipitation/snow over eastern locations should be realized from
Sunday into Sunday night and have issued a Winter Storm Watch 
over many eastern locations to account for this potential as 
healthy upper disturbance interacts with northerly component 
surface surge during this time-frame. 

Coolest temperatures during the longer term should be realized 
from Saturday into Tuesday, with warmer conditions returning by 
next Wednesday and Thursday as upper ridging moves across New 
Mexico.

&&

.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 345 PM MST Thu Dec 12 2019

VFR at all taf sites the next 24 hours, with increasing west winds 
after 15z-18z Thu. Higher terrain surrounding the San Luis Valley 
will see occasional snow showers overnight and through the day on 
Thu, but expect this activity to stay away from KALS until Thu 
night.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...

Winter Weather Advisory until 5 PM MST Friday for COZ059.

Winter Storm Watch from Friday afternoon through Sunday 
afternoon for COZ058>060.

Winter Storm Watch from late Saturday night through late Sunday 
night for COZ061>063-072>087.

Winter Storm Warning until 5 PM MST Friday for COZ058-060.

Winter Storm Watch from Saturday afternoon through Sunday 
afternoon for COZ066-068.

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