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979
FXUS65 KBOU 182045
AFDBOU

Area Forecast Discussion
National Weather Service Denver/Boulder CO
245 PM MDT Fri May 18 2018

.SHORT TERM...(This evening through Saturday)
Issued at 211 PM MDT Fri May 18 2018

Stratus deck still hanging on over most of the plains. Dew points
are still in the lower 50s F. Current ACARS soundings are still
showing a decent cap between 675 to 700 mb. Would need to get into
the 71-75 F range to get ride of it. It will no happen. The 19Z
special DNR sounding indicated the freezing level increased 1700
feet from this morning`s 12Z observation. The latest Platteville
profiler shows poor shear as well. We no longer expect severe
weather. Will adjust GFE pops and sky cover accordingly for the
rest of this afternoon/early evening. An observer in Breckenridge
is reporting snow with thunder right now. Models keep some upward
vertical velocity over the CWA tonight and much of Saturday. The
latest models are still showing the heavy rain/flooding potential
is still viable, so will keep the flood watch going. Concerning
the watch for snow in the mountains, only the GFS has high
precipitation amount in the high mountains, and the 12Z GFS
decreased those amount significantly from the previous runs. Will
go with an advisory at this time. For temperatures, there is still
a cold front expected late tonight/early Saturday morning
Saturday`s highs will be about 10 C cooler on Saturday from
today`s highs.

.LONG TERM...(Saturday night through Friday)
Issued at 211 PM MDT Fri May 18 2018

The upper low will shift east of Colorado Saturday night with the
brunt of the heaviest rain ending over the plains after midnight.
There will still be lingering moisture on Sunday morning with a
cloudy start. Some heating and lingering moisture will result in
scattered showers and thunderstorms Sunday afternoon especially
over elevated terrain like the foothills and Palmer Divide.
Overall dry and warmer on Monday and Tuesday with weak ridging
over the area. Another low will develop over the Great Basin
during the next week with continued southwest flow over Colorado.
the low ejects north of Colorado but will still result in enhanced
chances of precip and cooler temperatures towards the end of the
week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 211 PM MDT Fri May 18 2018

The Stratus deck never eroded away. Now there is a decent batch of
Cirrus over the low clouds from alpine convection. The temperatures
has even gone done a few degrees. Will keep cigs at or below BKN-
OVC020 for the foreseeable future. Will get ride of the thunder
and hail as well. More stratiform rain with embedded showers is
expected for DIA from early/mid evening through most of Saturday.

&&

.HYDROLOGY...
Issued at 216 PM MDT Fri May 18 2018

Main concern is with the flood potential across the Front Range
foothills and northeast plains of Colorado for tonight through
Saturday evening. Overall confidence is rather low on exact
locations for flooding but over impact amongst the models appear
to be from Denver northward and especially along and north of the
interstate 76 corridor up towards the Wyoming and Nebraska border
areas. Model qpf is anywhere from 1 to 5 inches, with the GFS
the highest with the a broad swath of 3-5 inches of rain from
Denver east and North. NAM highest qpf has shifted further west
back into Weld county. It will all depend on the exact track of
the low as it moves over Northern Colorado.


.BOU WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Saturday evening for COZ035-036-
038>040-042>045-048>051.

Winter Weather Advisory from 9 PM this evening to 6 PM MDT
Saturday for COZ033-034.

&&

$$

SHORT TERM...RJK
LONG TERM...Entrekin
AVIATION...RJK
HYDROLOGY...Entrekin