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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
840 PM MDT Monday Jun 1 2015

issued at 831 PM MDT Monday Jun 1 2015

Evening convection is diminishing across much of the County Warning Area at this
time except lingering storms over Phillips and Sedgwick counties
and further south across far souther Lincoln County. Still some
heavy rain...small hail and frequent lightning with this activity.
Water vapor imagery showing back edge of trough now across the
mountains with drying noted across northwest Colorado. Still some
isolate storms over Jackson and Larimer counties...but appears
most of this activity will be done before midnight. Some minor
forecast adjustments based on current trends.


Short term...(this evening through tuesday)
issued at 326 PM MDT Monday Jun 1 2015

Weak shortwave moving over the mountains and onto the plains this
afternoon with accompanying convection. Storms are organizing on
and outflow boundary at the front side...and along the trough axis
on the back side. Leading convection will be pushing into better
moisture over the next couple of hours. Temperatures are a little
cooler in the moist air...but convergence from the outflow should
be enough to overcome the weak capping. A bit more moisture than
yesterday in this area...but also less shear. Probably a better
chance of severe wind and hail than yesterday...but still

Meanwhile the second line of convection looks pretty well
organized...though it will be moving into a cooler/drier
environment as it comes off the mountains into Denver during rush
hour. More wind is the main threat...vertical motion is weaker but
it is an organized line. Still some weaker convection further west
but I do not expect this to survive east of the mountains...we
should have clearing in Denver in the early evening...and across
the plains by the middle of the night.

For Tuesday it should be drier at all levels and a little warmer.
Convection should be capped during the day...a slim chance of
getting storms going on the eastern border but the main threat of
this will be in the evening. Warm...dry...and breezy would mean
fire weather concerns but the grass is green everywhere with the fire
danger rated as moderate across most of our area.

Long term...(tuesday night through monday)
issued at 326 PM MDT Monday Jun 1 2015

The overall trend through from Wednesday through the weekend will
be a little cooler with a better chance of showers and
thunderstorms each day...especially from the Front Range foothills
eastward. Tuesday night will remain dry with the exception of the
far northeast plains in the evening. On Wednesday...a cool front
will slip in from the north early in the morning and settle along
the along the Front Range foothills and Palmer Divide in the
afternoon. A weak northeasterly upslope will develop below 700 mb in
the afternoon and evening. Should be mainly elevated thunderstorms
developing in the afternoon...then spreading east into the plains
in the late aftn/evng. The southwesterly flow aloft will be dry. A
weak system embedded in the flow aloft will aid in triggering the
showers/thunderstorms in the aftn/evng. The models show a magnitude of difference
regarding cape from the nam12 to the GFS buffer soundings...its all
or nothing. Severe threat will be present but may be further east
of the urban corridor than the nam12 suggests...but cannot rule
this out completely.

The flow aloft will remain southwesterly with an upper trough
along the central California coast for the rest of the period. Spatial
cross sections show a fair amount of low level moisture over the
northeast plains Thursday areas of fog/drizzle could
be around in the morning. Surface high pressure will remain in place
with the frontal boundary acting as the focusing mechanism.
Subtropical moisture off of Baja California may get entrained into the flow
aloft from a couple of decaying tropical storms. The trough itself
will be off the Southern California coast by 18z Friday...remains nearly
stationary over the weekend...then slips inland a bit over
central/Southern California on Monday. This will allow the aforementioned subtropical
moisture to advect across the Desert Southwest and into Colorado.
The threat of storms with heavier rain showers will be amplified
too. For now...will keep higher probability of precipitation each aftn/evng...but with some
lingering nocturnal activity as well.


Aviation...(for the tafs through 06z Tuesday evening)
issued at 831 PM MDT Monday Jun 1 2015

Showers appear to be done at terminals this evening with only
remaining activity to stay across Larimer and Weld counties.
Gradual clearing overnight as current southeast winds shift more
south and southwest by 06z. Drier and warmer on Tuesday with no
storms expected.


issued at 326 PM MDT Monday Jun 1 2015

Increased snowmelt will cause the poudre and the Platte in the
Greeley area to climb back above flood stage over the next couple
of days...which will cause renewed flooding in the most
vulnerable areas. Other rivers will be high and could cause some
minor impacts...but are expected to stay below flood stage.

An increase in thunderstorm activity along with slightly cooler
mountain temperatures are expected by this weekend. This would
lead to some decrease of the snowmelt...but also an increased risk
of significant runoff from thunderstorms. At this time the threat
of widespread significant rain looks low through the weekend...if
there are storms the threat would be localized.


Bou watches/warnings/advisories...


short term...gimmestad
long term...Cooper

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