359
FXUS63 KGLD 152048
AFDGLD

Area Forecast Discussion
National Weather Service Goodland KS
248 PM MDT Tue Aug 15 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 247 PM MDT Tue Aug 15 2017

Forecast issues will coverage of thunderstorms and associated
hazards. Satellite and upper air analsysis show a deep moist air
mass over the region. Main shortwave trough that will help with the
lift is just to our west at this time. Frontal boundary has
retreated some to the north through the day and is now over or near
the western and northern portions of the area.

High resolution/Cams are in disagreement where to put the convective
development which has been a problem they have been having this
season. At this time radar is showing thunderstorms developing near
the surface boundary. The Rap and latst Nam12 is showing this
scenario more than the other output. So at this time will start with
the highest pops in the north and west.

Guidance differs on how long to keep this activity around. Most of
the output is clustering around thunderstorms moving slowly east and
lasting through the night. Dcape looks to be 1000 or above over the
area through this evening and do have decent directional shear at
this time. Front and/or outflow moves across the area during this
time. So do expect a chance of severe with damaging wind and large
hail the main threats. There is an outside chance of a tornado.

Very heavy rainfall causing flash flooding looks to be higher than
normal. Precipitable water values are 1 to 1.5 inches which is near
to just above 1 to 1.5 standard deviations above normal. Locations
from Kit Carson through southeast Yuma and most of Sherman counties
into Cheyenne county Kansas and eastern Rawlins counties received to
2 to 6 inches with Kit Carson having the most widespread heavier
amounts. This combined where the models have the highest qpf and
pws, chose to put a Flash Flood Watch out for the northwest third.

For Wednesday the shortwave and associated precipitation moves
across the area through day and should be east of the area by late
in the afternoon. Models show cooler for tomorrow and used a blend
to cool temperatures off.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 205 PM MDT Tue Aug 15 2017

Over the extended period there will be a change in the upper level
pattern that will keep temperatures warmer and drier than the last
few weeks over the Tri-State region. To start off on Wednesday
night, precipitation chances are low as a shortwave trough moves east
of the region. As for Thursday, this is the best day during the
period that could see precipitation and storms. There is a broad
trough over the region and then a small shortwave passes over. This
will create uplift for storms to develop.

The remainder of the period will see ridging with southwest flow.
Mostly every day are showing signatures for precipitation with
moisture from the desert southwest being pulling into the region.

Temperatures are expected to remain the 80s for the period.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1134 AM MDT Tue Aug 15 2017

Main issue to address is when and where thunderstorms will be
later today into tonight. For Kgld, southerly winds will continue
through the early evening with gusts to near 20 knots. Some
discrepancy as to timing. Majority of the output says the best
chance for storms to affect site this evening. So at this time
chose to just add vcts from 02z to 06z. Wind shift with the front
occurs around 06z with sustained winds near 12 knots. At this time
vfr conditions are expected until 12z when mvfr conditions are
expected.

For Kmck, looks to be a better/more certain chance that
thunderstorms will affect site late this afternoon into this
evening. Mvfr conditions could occur with storms. Beginning at 07z
vfr conditions are expected as the front moves through around 10
knots.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Flash Flood Watch through late tonight for KSZ001-002-013.

CO...Flash Flood Watch through late tonight for COZ090-091.

NE...Flash Flood Watch through late tonight for NEZ079>081.

&&

$$

SHORT TERM...BULLER
LONG TERM...CLT
AVIATION...BULLER