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fxus65 kbou 201730 

Area forecast discussion
National Weather Service Denver/Boulder Colorado
1130 am MDT Wed Jun 20 2018

issued at 1127 am MDT Wed Jun 20 2018

Drying from the north winds and the continued warm air aloft will
significantly limit convection today. There will still be some
cumulus clouds and probably a few sprinkles around. With convective available potential energy
probably under 400 j/kg, we may not even have much lightning. Just
minor adjustments to lower our already low pops a bit more and
slightly warmer/windier out on the plains.


Short term...(today and tonight)
issued at 344 am MDT Wed Jun 20 2018

A drier and subsident airmass will be across the forecast area
today as the upper trough moves east into the Central Plains.
There will be some warming aloft and drying in the low levels,
the combination of which will keep instability limited to just a
couple hundred j/kg. There should be plenty of sunshine to help
push US to near convective temps, but still a little cin over most
of the plains outside of the northeast corner. It looks like
terrain will be the main focus for any convection, so look for
isolated to widely scattered thunderstorms in/near the Front Range
mountains and foothills this afternoon. Given the limited
instability, we expect only a brief period of moderate rain and
lightning from any storms that are able to develop.

Skies should be able to clear rather quickly this evening as we
lose any daytime heating and instability. That will lead to good
radiational cooling overnight. Overall forecast is right on track.

Long term...(thursday through tuesday)
issued at 344 am MDT Wed Jun 20 2018

A flat upper level ridge will develop over the area on Thu with
zonal flow aloft. There is some limited moisture over the higher
terrain which could lead to a isold high based storms in the aftn.
Across nern Colorado it looks dry with highs in the upper 70s to lower 80s.

On Fri a weak upper level trough will move across Wyoming and nrn Colorado. A
sfc Lee trough will be in place along the Front Range with
southerly low level flow across the plains. Instability will
increase across the far ern plains and as the weak upper level
trough moves across there will be a chance of late aftn/evening
tstms. Elsewhere tstm chances will be lower. Highs will be in the
80s across nern Colorado.

For Sat and upper level trough will develop over the nrn rockies
with westerly flow aloft across the area. Overall instability will
be less on Sat with a drier airmass in place so any tstm activity
will be very isold. Highs on Sat will remain in the 80s across
the plains.

By Sat night into sun an upper level trough will move south into Wyoming
as a cool front moves across nern Colorado. In addition there will be
some decent qg ascent moving into nrn Colorado so would expect an
increasing chc of showers and tstms across the plains late Saturday
night into sun. Highs on sun will likely only be in the 70s across
nern co.

For Sun night into Mon there are some differences between the European model (ecmwf)
and GFS with the handling of an upper level low. The European model (ecmwf) keeps
the low just north of nrn Colorado while the GFS has it further south near
Denver. As a result the GFS has much more pcpn across portions of
nern Colorado Sun night into Mon while the European model (ecmwf) keeps most of it to the
east and northeast. At this point really hard to say where the low
will end up so will will go with a blended solution.


Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 1127 am MDT Wed Jun 20 2018

VFR through tonight. North winds at 10-20 knots this afternoon
with a slower than normal transition to south winds this evening
due to the northerly pressure gradient.


Bou watches/warnings/advisories...


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