Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 242041
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
241 PM MDT TUE MAY 24 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 240 PM MDT Tue May 24 2016

As a shortwave moves overhead, several storms have formed in the
moist airmass as CAPE values are between 1500 and 2000 J/kg and
good shear. Dewpoints near the urban corridor are in the mid to
upper 40s with higher dewpoints to the east. These storms have
already produced hail stones up to golfball size, this will
continue with even larger hail possible through the afternoon and
early evening. The southeasterly surface winds veer to the
southwest with height providing good shear for storm growth.
Surface boundaries may take advantage of the shear and produce a
few tornadoes this afternoon and evening. The current Tornado
Watch goes until 8pm. Hi- res models continue to show the best
chance for strong storms mainly from Denver County then to the
north and east. Models continue to show drier dewpoints pushing up
from the south, which values are in the mid 30s south of Palmer
Divide. This may provide additional focus for storms. Storm
activity will be pushing northeast out over the plains and likely
be done by 5 pm over the metro areas then last over the far
northeastern corner through 9 pm. Though some models keep storms
forming over the far corner past midnight, have kept a slight
chance of storms out there. Otherwise, skies will be clearing
tonight over the area which may allow some patchy fog to develop,
most likely along the South Platte River valley.

A shortwave ridge will push overhead tomorrow over the area to
bring warmer and drier weather. Only a slight chance of showers
and thunderstorms are expected over the mountains and the far
northern plains near the state border. Highs tomorrow will be a
few degrees warmer over the plains, but a few degrees cooler over
the mountains where cooler air will be dropping down from an upper
low over the Great Basin.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 240 PM MDT Tue May 24 2016

The next weather system in this unsettled weather pattern will
begin to impact the area Thursday. Large scale lift will increase
through the day. At the same time, low level moisture is expected
to increase with persistent easterly flow with a theta-e ridge
developing over northeast Colorado. Not exactly sure how much
surface heating will occur with the large scale lift, but still
enough instability near 1000 J/Kg to produce a threat of severe
weather, including hail and a tornado or two depending on where
low level boundaries set up.

The precipitation is expected to transition to more widespread
rain showers/embedded thunderstorm event Thursday night into at
least Friday morning with persistent large scale lift and Q-G
ascent. Will increase PoPs into the likely category for most of
this period from the foothills east onto the plains. Widespread 1
inch rainfall amounts a good bet during this period but no
significant hydrology issues expected at this time.

Drier weather will then work in for Friday night into most of
Saturday with weak subsidence. Can`t rule out an isolated storm
drifting out of the mountains late in the day or evening, but
overall looks like a pretty dry and mild Saturday shaping up.

Sunday looks mild as well with southwest flow aloft. Enough
heating and moisture to support a few more afternoon showers and
storms, but coverage still limited.

By Monday and Tuesday, upper level support and moisture is
expected to increase again with another weak wave noted. That
should support a better chance of showers and thunderstorms.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 240 MDT Tue May 24 2016

VFR conditions expected through Wednesday. A line of scattered
thunderstorms from Fort Collins down to KDEN will continue to push
northeast. These are expected to be the strongest...but additional
thunderstorms are still possible later this afternoon. Wind gusts
to 40 knots, hail, and heavy rain will continue to be possible
with the thunderstorms. Drier air will move into the area after
00z and bring mostly clear skies by 06z. Patchy fog is expectedto
form after midnight along the South Platte River valley, but at
this time it is not expected to move south into KDEN. Drier
weather is expected Wednesday with light winds.

&&

.BOU Watches/Warnings/Advisories...
None.
&&

$$

SHORT TERM...Kriederman
LONG TERM...Barjenbruch
AVIATION...Kriederman



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