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Area forecast discussion 
National Weather Service Denver/Boulder Colorado
1011 am MDT Wednesday may 27 2015

issued at 952 am MDT Wednesday may 27 2015

Satellite shows continued development over the high country as the
surface trough makes it way south. Moisture ahead of it will bring
increased convection chances earlier in the afternoon for the
higher foothills with some minor development over the plains.
Drier air near the foothills will help to stall the development
early on but with a weak cap and increased moisture from westward
movement afternoon convection will be possible. Brief heavy rain
and small hail with gusty winds are still the predominant threat
over the urban corridor but with the dryline setting up over the
far eastern plains and dewpoints already in the middle 50s expect
strong to severe storms later this afternoon. Hail up to 1 inch in
diameter and wind gusts up to 60 miles per hour could develop. As the
evening progresses low level winds increase as does srh over the
far northeastern plains counties so isolated tornadoes will also
be possible.


Short term...(today through tonight )
issued at 442 am MDT Wednesday may 27 2015

Colorado is going to be under weak west-southwest flow aloft in
between the weak upper disturbance that passed last night and
another upper trough which will be developing over Utah today. At
the surface...pressures will be falling over the mountains through
the day...inducing south to southeasterly winds across the eastern
Colorado plains. The airmass will remain moist and by afternoon
the airmass should be moderately unstable. Model soundings only
indicate 700-1000 j/kg of strong thunderstorms are not
expected. The Storm Prediction Center has a slight risk of severe
thunderstorms indicated east of a Limon to Akron line...where the
strongest storms should be located. Areas that see strong storms
develop could see localized flash flooding develop...but this
should be limited to the eastern locations. Closer to the
foothills should see a round of showers develop by middle-afternoon
which moves east of the I-25 corridor before the afternoon rush
hour gets going. Later in the evening...showers should be confined
to the eastern plains. Temperatures should be just a degree or two
shy of normals for the date.

Long term...(thursday through tuesday)
issued at 442 am MDT Wednesday may 27 2015

The upper trough will be crossing the northern and central rockies
Thursday with southwest flow aloft becoming west by Friday.
Surface low over the eastern state border will keep higher
moisture and cape values over the eastern plains. This combined
with temperatures a degree or two warmer will have another day of
potentially strong storms over this area...with gusty outflow
winds and hail the main threats. For the mountains...expect
slightly cooler temperatures as the upper disturbance pushes in
earlier...especially north of i70. A cold front is expected to
push south across the area late Thursday evening...which may be
pushed in faster by developing convection. There is some
difference of chances of rain overnight with the NAM becoming
quite dry. Will continue probability of precipitation through the night with the expected
upslope flow developing and upper trough overhead.

With cooler temperatures behind the front and more moisture into
the area Friday...expect showers to become widespread especially
along the foothills and Palmer Divide. Will still have some
available weak cape around...leaving a slight chance for thunder
as well. Overall rain amounts over the forecast area keep
changing...however can expect the higher amounts toward the higher
terrain and adjacent plains. A half to one inch will not be out of
the question through the day...with a few locations seeing more
under heavier storms. Will have precipitation chances decrease Friday
night following the non-NAM model the NAM seems to
be the slowest of all to push the system through.

Saturday will remain a cool day...especially over the plains as
high surface pressure keeps a more stable cooler upslope flow
regime over the area. The high country will likely see warmer
temperatures and normal diurnal afternoon showers and
thunderstorms...with much less available moisture.

A stronger upper ridge will move overhead Sunday and Monday to
likely warm temperatures to near or above normal for this time of
year. The plains could see 80 or above by Monday. Expect a normal
diurnal convection pattern through these days as some moisture is
expected to remain under the ridge as well as some additional
being transported in Monday as flow turns southwesterly.


Aviation...(for the tafs through 18z Thursday morning)
issued at 952 am MDT Wednesday may 27 2015

VFR conditions will continue through the morning. Afternoon
convection will develop my 21z in the vicinity with possible
thunderstorms by 22z over the Airport. Ceilings are not expected
to drop below VFR but brief heavy rain accompanied with wind gusts
up to 30 miles per hour will be possible between 22 and 24z. A middle level broken
deck will remain through the evening with winds switching to


issued at 952 am MDT Wednesday may 27 2015

Current rfc forecast has South Platte at Weldona below flood stage
with a continual downward trend so cancelled Flood Warning for
that portion. Flood warnings for the South Platte at Kersey as
well as Cache la poudre at Greeley continue. Afternoon storms
today will bring the chance for brief heavy rain however the above
mentioned rivers are not expected to be adversely affected and
should continue the forecasted trend.


Bou watches/warnings/advisories...


short term...dankers
long term...kriederman

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