Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 270849

Area Forecast Discussion
National Weather Service Denver/Boulder CO
249 AM MDT Sat May 27 2017

.SHORT TERM...(Today and tonight)
Issued at 139 AM MDT Sat May 27 2017

An upper level trough will move across the area today and then move
southeast of the area by this evening.  Meanwhile sfc high pres will
move into nern CO with upslope low lvl flow.  As a result will see a
good chc of showers with a few tstms across the rgn today. Activity
will decrease fm nw to se by late aftn into the early evening hours.
Snow will occur in the mtns abv 10000 feet with 2 to 4 inches
possible in some areas.  As for highs readings will only be in the
upper 50s to lower 60s across most of nern CO.  By tonight pcpn will
gradually end by early evening as the upper level moves out of the

.LONG TERM...(Sunday through Friday)
Issued at 139 AM MDT Sat May 27 2017

Sunday and Sunday night, a moderate northwesterly flow aloft will
be over CO with an upper level ridge centered over NV. The
airmass will be drier, but still enough moisture around in the
afternoon to trigger scattered showers and tstms. Surface high
pressure over the northeast plains will keep isold to scattered
showers and tstms in the afternoon, especially over the mountains.
Not much instability over the plains with fcst CAPES of 100-200
j/kg in the aftn. In addition, a weak disturbance embedded in the
flow aloft is progged to clip northeast CO late Sunday night,
which may help to produce some late night/erly showers around 12z
Monday. The overall pattern will not change much through the
middle part of the week, with temperatures gradually modifying. A
surface high will help to cap most the thunderstorm activity over
the northeast plains, with the best chc of showers and storms
over the mountains. Discrepancies pops up at the end of the week
between the GFS and ECMWF. The GFS shifts eastward with the flow
aloft transitioning from northwesterly to southwesterly. The ECMWF
maintains an upper level ridge over the region. For now will
continue with typical showers/tstm coverage each aftn/evng over
the area.


.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 139 AM MDT Sat May 27 2017

Stratus deck is over the area early this morning with MVFR ceilings.
GLAMP data indicates MVFR ceilings will continue thru late morning.
Winds were light nnw but may become more variable by 12z.  By late
morning thru mid aftn shower coverage will increase with a slight
chc of a tstm.  Visibilities may briefly drop down to 3-5 miles with
the showers.  By late aftn the pcpn should gradually end with
ceilings improving.  Winds fm late morning thru the aftn will be
mainly nne.  By evening winds will gradually become drainage.
Ceilings around 6000 ft may linger thru 03z but then should
gradually break up before 06z.




LONG TERM...Cooper
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