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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
615 PM MDT Monday Sep 15 2014

issued at 610 PM MDT Monday Sep 15 2014

Updated forecast for patchy fog after midnight mainly over
Lincoln County. Stratus already in forecast...current area of
stratus over southeast Colorado is expected to be pushed back in
with southeasterly winds. Hrrr and rap short term models both
hinting of fog developing around or after midnight. Southeasterly
winds of 10 to 15 miles per hour with gusts to 25 miles per hour may limit the amount of
fog to develop...but still have high humidity kept
the coverage to patchy instead of areas of or widespread fog.


Short term...(this evening through tuesday)
issued at 205 PM MDT Monday Sep 15 2014

Pressure falls across eastern Wyoming will spread into eastern
Colorado Monday afternoon and surface winds by evening will
become more south-southeasterly over the plains in response. Will
probably see a Denver cyclone set up by late afternoon. Convection
is forming in the mountains but atmosphere on the plains is more
stable and moisture is limited. Therefore expect thunderstorms to
remain in and near the mountains. Storms will have limited
coverage of rainfall but may produce brief gusty winds.

Chance for afternoon convection is even less on Tuesday as large
ridge builds over the region. Precipitable water values and surface dewpoints will
likely be a little lower Tuesday than today. Afternoon cumulus near
the mountains and the possibility of a few cirrus may decrease
solar input a little but expect above average temperatures reaching the
middle 80s in many lower elevation areas.

Long term...(tuesday through sunday)
issued at 205 PM MDT Monday Sep 15 2014

An upper level ridge over the SW portions of the US will be over
Colorado on Wednesday and remain in place through Thursday morning before it
moves east. There is adequate middle level moisture Tuesday evening
into Wednesday morning for a possible wave cloud set-up over the
Front Range that will advect east through the afternoon and
dissipate. Some light moisture will hang in the mountains so will
keep a slight chance of thunderstorms over the higher mountains
for Wednesday afternoon. Conditions will be stable over the
foothills and urban corridor..which will hinder any thunderstorm
development. Models are showing a weak surface low dipping into the
far NE portions of the state bringing in some ll moisture but
soundings are capped so little development will take place. Temperatures
will continue to increase Wednesday and Thursday over NE Colorado as ridging
combined with downslope flow will aid in stabilizing and heating.
Look for temperatures to be in the middle 80s with lower 80s out on
the plains.

By Thursday afternoon the upper level ridge will have started to move
east with flow turning more southerly as the remnants of
Hurricane Odile moves in from the SW. Conditions will remain dry
Thursday as the tropical moisture is still embedded in the flow to
the south. Will keep a slight chance in the mountains with temperatures
increasing into the lower 90s for the plains. The models have
diverged a bit with the moisture advection and front prognosticated to
move in Friday. Both the GFS and the ec move the tropical
moisture from Odile north-northeast into the southern portions of the state by
12z Friday. The GFS however has increased and deepened the
moisture from this system unlike the ec which keeps it more in the
upper levels with drier conditions near the surface over the
plains. At this time it still looks like the best chance for
precipitation will be in the mountains with a slight chance over the
plains. Temperatures will be in the middle 80s but timing will
depend on when the front moves through.

Flow will turn northwest on Saturday as surface high pressure
builds back in to the region. There will be lingering moisture
over the mountains so will put in a slight chance of storms for
Saturday afternoon with the plains remaining dry. Highs will drop
back into the lower to middle 70s Sat. On Sunday moisture from a
system moving over Southern California will advect into the SW portions of
the state so will keep a slight chance of ts over the mountains
for Sunday as well with temperatures continuing to rebound back
into the middle 70s to lower 80s.


Aviation...(for the tafs through 00z Tuesday late afternoon)
issued at 205 PM MDT Monday Sep 15 2014

Thunderstorm activity on Monday evening will likely stay in and
near the mountains, and little or no thunderstorm activity is
expected Tuesday. Stratus and fog development in the predawn hours
on Tuesday should be less extensive than the clouds on Monday
morning and the Denver area airports are not expected to see low
clouds. A windshift to the north is expected by late Tuesday
morning and then the winds on Tuesday afternoon are expected to
become light and follow the diurnal pattern of switching around
to the east and then southeast.


Bou watches/warnings/advisories...


short term...gimmestad/kelsch
long term...rpk

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