Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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430
FXUS65 KBOU 231005
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
405 AM MDT Wed May 23 2018

.SHORT TERM...(Today and tonight)
Issued at 249 AM MDT Wed May 23 2018

Today will be characterized with drier conditions over the
mountains and adjacent plains, while isolated thunderstorms are
forecast over the far eastern plains and will result in a
marginal threat of severe storms.

The Great Basin upper low will continue to lift north and
eastward resulting in a drier southwest flow aloft over central
Colorado and a more subsident airmass. QG fields showing this
subsidence especially over northern mountain sections and more
neutral forcing over the eastern plains. Main change in the
forecast was to reduce storm chances over the mountains and keep
a remaining small threat over the far plains.

Over the eastern plains, surface trof of low pressure will
develop with increasing southwest winds surging northward from the
Palmer Divide. This will set up a convergence boundary with drier
air to the south and the remaining moist air north of the
boundary. Best chance for storms will be north and east of the
boundary, mainly from Limon to Fort Morgan and points north and
east. surface based CAPES progged upwards of 2000j/kg as surface
dewpoints remain in the lower 50s while mid level flow in the
35-45kt range. over the far northeast plains. SPC has much of the
far northeast in a marginal risk for severe storms and this looks
reasonable. Main threat would be large hail and damaging winds.
Mountains and adjacent plains could see isolated showers/storms,
but mainly high based with gusty winds and not much rain.
Temperatures today will be slightly warmer with good mixing below
500mb while 700mb temperatures climb to +12c. Much of the
convection expected to diminish by late evening with clearing
skies.

Elevated fire weather concerns over the Palmer Divide with gusty
southwest winds but rh levels not quite low enough to result in
red flag hilites.

.LONG TERM...(Thursday through Tuesday)
Issued at 249 AM MDT Wed May 23 2018

As the closed low exits to the NE Thursday with upper level ridging
increasing over the four corners region. This will help to decrease
convective activity and increase temperatures into the upper 80s to
possibly low 90s by Saturday. Even though atmospheric parameters
during this time is not highly conducive to convective
development, an isolated storm that moves off the higher terrain
and onto the plains cannot be ruled out.

By Sunday, the closed low that was over the Pacific will have moved
onshore over the West coast and into the Great Basin. This will
increase SSW flow with an embedded shortwave moving NNE into the
state Sunday night into Monday morning. Models show the set-up of a
lee side low pulling in strong SE winds over the eastern border
counties and cooler NW with the surface feature. This could help to
determine just how much LL moisture gets pulled into the plains for
convective development. Looking at possible severe storms Monday
afternoon or Tuesday depending on when the ingredients can come
together the best. However, storms will be possible both days.
Temperatures will cool slightly from Saturday with highs in the
low to mid 80s Monday and upper 70s Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 249 AM MDT Wed May 23 2018

VFR with mainly clear skies this morning. normal drainage patterns
this morning with south to southwest winds which will increase
this afternoon from the southwest with strong mixing below 500mb.
Any storms today should remain north and northeast of the
terminals but could be some return n-nw winds late in the day or
evening from outflow from showers/storms.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

$$

SHORT TERM...Entrekin
LONG TERM...Bowen
AVIATION...Entrekin



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