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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
309 PM MDT Tuesday Sep 2 2014

Short term...(this evening through wednesday)
issued at 308 PM MDT Tuesday Sep 2 2014

All is quiet on the western front this afternoon. A bit of cumulus
has developed over the high country about as expected which should
dissipate with the setting sun. Little in the way of quasi-
geostrophic dynamics expected through the period. Precipitable
water values are forecast to be a bit higher tomorrow than is the
case today but still nothing to get excited about...maybe some
more cumulus than today. The CIRA WRF simulated satellite imagery
depicts some stratus over Lincoln County and its environs around
sunrise Wednesday...similar to today...and have included this in
the grids.

The main issue for tomorrow is an increase in the winds and the
above normal high temperatures due to increasing pressure
gradients and downslope component. Beastly 90+ readings are
expected at lower elevations with above normal maxima in the high
country as well. Official record high of 95 at dia set in 1995
could be threatened. Low humidities in and close to the mountains
will combine with the winds to elevate the fire danger especially
in South Park. No plans for fire weather highlights at this time.

Long term...(wednesday night through tuesday)
issued at 308 PM MDT Tuesday Sep 2 2014

Dry weather will remain in place through Wednesday night and most
of Thursday. By late Thursday...mid/upper level moisture begins
to increase in/near the mountains by late in the day. The low
levels are quite stable so any convective showers/storms that
develop in the high country will likely dissipate as they attempt
to move into the lower elevations of the plains. Have trimmed back
the eastern extent of the already low probability of precipitation...but some further
refinement could be necessary to remove them from the I-25
corridor as well. For now...have kept low probability of precipitation in considering our
proximity to the right rear entrance region of departing upper
level speed maximum.

On Friday and Saturday...surface high pressure builds over the
Central Plains. This will keep a relatively cool and slightly
stable airmass across most of the Colorado plains. At the same
time...there is a modest Theta-E ridge building along the Front
Range and over the mountains...which should bring scattered
shower/storm development each afternoon and evening. Would expect
a few of these to drift onto the plains each late
afternoon/evening as well...with a weaker cap and again the close
proximity of the upper level speed maximum. Temperatures should remain
a few degrees below normal on the plains with the cooler high
pressure and light easterly upslope flow across the High Plains.

On Sunday...weak Lee troughing will likely develop as Central
Plains high pressure retreats to the east. This should allow
temperatures to rebound to near normal temperatures. Convective available potential energy may
also increase with southerly low level flow and increased low
level moisture...resulting in a few stronger storms. Overall...
the forecast area remains on the northern edge of any deeper
monsoonal moisture so the threat of any heavy rainfall is low
due to expected faster storm motions and limited precipitable

By late Monday or Tuesday...we see some potential for drying with
a larger trough moving in from the Pacific northwest. This would
sweep any deeper moisture to the east and lower the chance of any
showers/storms. Timing is somewhat uncertain here with the latest
12z European model (ecmwf) showing a slower eastward advancement of this trough.


Aviation...(for the tafs through 00z Wednesday late afternoon)
issued at 308 PM MDT Tuesday Sep 2 2014

Ceiling and visibility OK through Wednesday. A weak westerly push swung the winds
around to westerly at kden. The feature shows up on the Doppler
velocity but it is not clear what it is. The hrrr has a hint of it
but it washes out later this afternoon with east southeasterlies
reforming. The other two terminals were less impacted by this.
Drainage flow expected to form overnight which may be a enhanced
just a bit late tonight as low pressure develops to our northeast.
Expecting generally light flow tomorrow which should favor a
southwesterly direction.


Bou watches/warnings/advisories...none.



long term...barjenbruch

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