Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 281635

Area Forecast Discussion
National Weather Service Denver/Boulder CO
1035 AM MDT SAT MAY 28 2016

Issued at 1035 AM MDT Sat May 28 2016

No need to make any changes to the forecast at this time. Model
soundings show somewhere around 1000 j/kg of CAPE for convective
development with surface temperatures around 70 degrees necessary
to initiate shower development. Wind fields are not particularly
strong, but do have the proper turning with elevation and should
be sufficient for at least a few thunderstorms to develop. It is
the end of May, after all. The latest runs of the HRRR indicate a
round of showers rolling off the foothills by 1 PM and then moving
over Denver and then the Palmer Divide through the afternoon.
Small hail...gusty winds and brief rain will be the primary
threats. Another batch of showers may also move over Weld and
Logan Counties after 2 or 3 PM.


.SHORT TERM...(Today and tonight)
Issued at 350 AM MDT Sat May 28 2016

The upper level low that brought cool conditions and showers
yesterday has moved into Nebraska. Behind it, a weak ridge in a
westerly flow aloft will be over Colorado today. Airmass is drier
and will result in mostly sunny skies for this morning. It will
become a little unstable this afternoon with CAPEs up to 500 J/kg.
Models in decent agreement with scattered thunderstorms forming
this afternoon over the higher terrain, including the Cheyenne
Ridge and Palmer Divide. A few of these storms are expect to
survive off the higher terrain. Weak instability and little shear
will keep storms well below severe threshold today. The storms
will end this evening as the airmass stabilizes. With the
increased sunshine today, highs will climb into the upper 60s to
lower 70s. Still a little below normal for this time of year.

.LONG TERM...(Sunday through Friday)
Issued at 350 AM MDT Sat May 28 2016

The upper ridge mentioned above remains positioned over Colorado
on Sunday but in a weakened state due to a series of weak
pertabations passing over the state in west-southwesterly mid-
level flow. The NAM continues to be more bullish with these
features particularly with the wave moving off the Front Range
Sunday afternoon. Height falls with this wave together with stg
solar heating produce pressure falls along the Front Range which
in turn strengthens the southeasterly gradient wind on the plains
through the afternoon. In doing so..models show low-level
moisture/lower 50s dewpoints/ feeding northwestward up into nern
Colorado which aids in producing bndry layer CAPES in the
500-1500 j/kg range in areas roughly east of a Briggsdale-to-
Kiowa line by mid-afternoon. Main axis of this elevated instability
and moisture appears lies across northern Lincoln and Elbert
Counties...but in time shifts north across the northeast corner of
the state with passage of the shortwave energy. The threat for
severe storms appears marginal at best at this time and mainly
acrs far sern sections of the CWA late afternoon/early evening.
Large hail being the main threat. Otherwise temperatures Sunday
look slightly warmer with max readings near average for most
locations. Overnight...shower and t-storm chances decrease from
west to east with drier southwesterly flow in place.

by Memorial Day...the upper ridge shift east of the area allowing
a west-northwest flow aloft to usher in another batch of mid-level
energy and moisture for another round of afternoon and evening
convection. That`s after a dry and mild morning. Temperatures on
Monday expected to be near to slightly warmer than those on
Sunday. Could see showers and t-storms lingering well into the
night esply on the plains with a sfc cold front forecast to slide
south acrs nern Colorado during the pre-dawn hours. For that
reason could see a jump in storm coverage on the far plains after

Tuesday and Wednesday turn cooler with long wave upper trough
passing over the northern and central Rocky Mtn region. Temps as
much as 10-15 degs cooler with plenty of cloud cover along and
east of the Front Range on Tuesday with anticyclonic upslope flow.
Showers chances also higher but cooler temps and cloud cover
should keep t-storm formation down on the plains. Wednesday dries
out but northwest flow on the back side of the departing trough
will hold temps several degrees below average.

by Thursday and Friday...warmer and drier conditions should
return the forecast region with the strong upper ridge over the
Great Basin moving toward Colorado. Should see temp near to aboveaverage
by the end of the week and the chance for precip near zero for
most locations.


.AVIATION...(For the 18Z TAFS through 18Z Sunday afternoon)
Issued at 1035 AM MDT Sat May 28 2016

Depending on how showers over the foothills develop in the next
hour, may need to add an hour or two of showers and thunderstorms
to the Denver area TAFs. The HRRR model indicates that shower and
thunderstorm activity should be east of Denver by 2 or 3 PM. After
that, a return to VFR conditions with high ceilings and unlimited
visibilities is expected.


.BOU Watches/Warnings/Advisories...


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