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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
311 PM MDT Monday Apr 27 2015

Short term...(this evening through tuesday)
issued at 311 PM MDT Monday Apr 27 2015

Low cloud deck has been quite persistent as expected along the
Front Range...but slowly lifting. A few showers still noted as
well...but these are expected to gradually dissipate as airmass
stabilizes through the evening. Main concern surrounds potential
for clearing and fog development overnight. The flow in the moist
layer between 800 and 700 mb has a weak upslope component through
06z...and then becomes light/variable thereafter. As a
result...should see mainly cloudy skies through evening and then some
breaks develop overnight...but doubtful it will fully erode.
Meanwhile...the very moist and light flow in the boundary layer
would be conducive to dense fog development. If clouds break
sufficiently...then we could see more widespread fog develop
across the plains with potential for a dense fog advisory. Given
only partial clearing is expected at this time...will go with
patchy fog over most of the plains late tonight into Tuesday
morning. Will continue to monitor this through the evening and

For Tuesday...any morning fog should burn off by middle to late
morning as cloud deck erodes further and daytime heating occurs.
Only a slight risk of afternoon showers...mainly over the higher
terrain where sufficient instability exists. Otherwise high
temperatures should be able to climb back into the lower to middle
60s with more sunshine returning.

Long term...(tuesday night through monday)
issued at 311 PM MDT Monday Apr 27 2015

Benign weather and a gradual warming trend will dominate through
about Thursday. An upper ridge is building over the southwestern
United States which will extend over Colorado. Temperatures will
be warming as winds aloft diminish. High temperatures will warm
into the 70s across the plains for Tuesday...Wednesday and
Thursday. Thursday looks to be the warmest day of the week. On
Friday...the upper ridge will still be in place...but middle-level
moisture will be increasing over the state from the south. This
will allow the airmass to begin Delaware-stabilize during the
afternoons. Saturday and Sunday should see heights over Colorado
beginning to decrease as weak upper level troughiness moves into
the Rocky Mountain region from the Pacific northwest. This should
lead to a less settled weather pattern over the weekend with a
chance of showers and thunderstorms across the forecast area for
each afternoon and evening. Probability of precipitation will be highest in the mountains
for now...owing to the elevated heat source of the higher terrain
receiving strong insolation during the morning hours. Temperatures
over the weekend will be around or slightly above normal.


Aviation...(for the tafs through 00z Tuesday late afternoon)
issued at 311 PM MDT Monday Apr 27 2015

Low clouds with ceilings 1000-2000 feet in the Denver metropolitan area
are slowly lifting and should continue to slowly rise into early
evening. Still some patchy light rain showers with visibilities
3-4sm but these will be gradually decreasing through 02z. Ceilings
have already lifted to 3000-4000 feet to the north around Fort
Collins...and expect ceilings to slowly increase to 3000-4000 feet
in the Denver metropolitan area airports through 02z. However...local
ceilings down to 2000 feet still possible as a shallow upslope
component remains in place through that time.

Cloud deck is likely to hold in place most of the night...but a
few more breaks should occur after midnight into the early morning
hours Tuesday. If ceilings break...look for relatively high
potential of fog formation given the light and very moist
boundary layer flow. Visibilities 1/4sm or less will be possible
10z-15z early Tuesday morning. At this time...a tempo fog group
with lower visibilities of 1/4sm to 1/2sm seems prudent 10z-15z.


Bou watches/warnings/advisories...


Short term...barjenbruch
long term...dankers

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