Hail and Damaging Winds in Colorado, June 22, 2018

Area Forecast Discussion
National Weather Service Goodland KS
1210 PM MDT Fri Jun 22 2018

.UPDATE...
Issued at 1145 AM MDT Fri Jun 22 2018

As of 18Z, deep convection in northeast Colorado was progressing
southeast toward northwest KS - and was already in the process of
growing upscale. Observational trends indicate that the most
favorable insolation/low-level moisture will be along/south of
I-70 this afternoon -- and this is where the greatest severe
weather potential will exist. Expect damaging winds to be the
main threat, though isolated instances of large hail will be
possible in assoc/w embedded rotating updrafts, primarily before
significant upscale growth occurs.

&&

.SHORT TERM...(Today and tonight)
Issued at 327 AM MDT Fri Jun 22 2018

The primary concerns in the short term are the possibility of
severe thunderstorms across the area both this afternoon and
evening and again on Sunday afternoon and evening.

An upper trough moves across the central high plains this evening
with zonal flow on Saturday ahead of the stronger upper low
expected to emerge east of the Rockies over the central and
northern high plains on Sunday.

Storms will develop rapidly over eastern Colorado this afternoon
in the surface convergent area of upslope flow that transitions to
a southerly direction and transports near 60 degree dewpoint air
into the forecast area. Storms will migrate across mainly the
western and southwestern portions of the forecast area as a
surface low consolidates in the vicinity of the panhandle region
and moves east overnight.

A few storms are expected on Saturday night into Sunday morning,
but the main thunderstorm activity will develop on Sunday
afternoon as the stronger upper low emerges east of the Rockies.
Another surface low develops in the panhandle region with a strong
low level southerly jet that transports mid 60 dewpoint air into
the region along with a warm frontal boundary. Strong
destabilization is expected as the low brings in cooler
temperatures aloft in combination with the ample low level
moisture and a warm front moving into the region. Expect storms
to become more widespread through Sunday afternoon and evening
with storms becoming severe and eventually consolidating into an
MCS as they move out of the forecast area by late Sunday.

.LONG TERM...(Monday through Thursday)
Issued at 250 AM MDT Fri Jun 22 2018

A trough centered over the Tri-state region Monday is expected to
move northeast towards the upper Midwest Monday night. As the
trough exits the region, thunderstorm chances move eastward. Zonal
flow aloft replaces the trough leading to above normal
temperatures through the end of the week and drier conditions.

A shortwave embedded within a forming ridge moves over the region
Wednesday night and Thursday morning bringing slight chances of
thunderstorms. Ridge building begins Wednesday night as a trough
forms over the western CONUS. This is where noticeable spatial
differences start to occur between the GFS and ECMWF. The GFS
seems to be more progressive while the ECMWF builds a deeper
trough over the west coast.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1145 AM MDT Fri Jun 22 2018

Thunderstorms were already developing and intensifying in
northeast Colorado at 17Z. Activity is expected to grow upscale
and track ESE/SE through northwest Kansas this afternoon and will
affect the GLD terminal between 19-23Z. Large hail and surface
wind gusts up to 60 knots will be possible. Confidence is lower
that thunderstorms will affect the MCK terminal. Aside from
thunderstorms this afternoon and evening, VFR conditions will
otherwise prevail. Winds at the MCK terminal are expected to be
variable at 6-12 knots for the majority of the TAF period.
Initially south winds at GLD are expected to become variable at
6-12 knots after thunderstorms this evening/tonight.

&&

.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&

UPDATE...VINCENT
SHORT TERM...LOCKHART
LONG TERM...BLN
AVIATION...VINCENT

Hazardous Weather Outlook...UPDATED
National Weather Service Goodland KS
1234 PM MDT Fri Jun 22 2018

COZ090>092-KSZ001>004-013>016-027>029-041-042-NEZ079>081-231845-
Yuma County-Kit Carson County-Cheyenne County-Cheyenne-Rawlins-
Decatur-Norton-Sherman-Thomas-Sheridan-Graham-Wallace-Logan-Gove-
Greeley-Wichita-Dundy-Hitchcock-Red Willow-
1234 PM MDT Fri Jun 22 2018 /134 PM CDT Fri Jun 22 2018/

This hazardous weather outlook is for extreme southwest Nebraska...
northwest Kansas and east central Colorado.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

...Severe Thunderstorm Watch 198 is in effect until 8 pm MDT /9 pm
CDT/ this evening for portions of the Tri-State area...

Thunderstorms in northeast Colorado will track southeast through
northwest Kansas this afternoon and early this evening. These storms
will be capable of producing damaging wind gusts up to 70 mph and
a few instances of golf ball size hail. Locally heavy rain and
isolated flash flooding cannot be ruled out.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH FRIDAY...

...Enhanced Risk for Severe Thunderstorms on Sunday...

Severe thunderstorms capable of producing large hail and damaging
winds will be possible across much of the Tri-State area Sunday
afternoon and evening. Locally heavy rainfall and flash flooding
will also be possible.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required.

Vincent

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
1243 PM MDT FRI JUN 22 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1237 PM     TSTM WND GST     YUMA                    40.12N 102.72W
06/22/2018  E50 MPH          YUMA               CO   EMERGENCY MNGR

            WIND GUSTS ESTIMATED AT 50 MPH.

&&

VINCENT

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GOODLAND KS
144 PM MDT FRI JUN 22 2018

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0140 AM     HAIL             2 W KIRK                39.62N 102.63W
06/22/2018  E0.50 INCH       YUMA               CO   TRAINED SPOTTER

&&