Special Weather Statement, NWS Grand Junction, CO

Area Forecast Discussion
National Weather Service Grand Junction CO
231 PM MDT Fri Aug 6 2021

.SHORT TERM...(Tonight through Saturday night)
Issued at 230 PM MDT Fri Aug 6 2021

A shortwave over Idaho will move across Wyoming overnight. High-
based convection continues across the forecast area this afternoon
with the best coverage along and north of Interstate 70. Expect
convective activity to continue into the early evening hours with
the greatest threat being lightning and strong gusty outflow winds
up to 50 mph with these storms. With these fast-moving high-based
storms brief heavy rain is possibly with the strongest cells.
Shower and thunderstorm activity will diminish this evening as
this system moves east. High Pressure will move across the region
tomorrow with dry conditions and cooler temperatures expected.

.LONG TERM...(Sunday through Friday)
Issued at 230 PM MDT Fri Aug 6 2021

A closed low over western Washington on Sunday will move east
across the Montana on Monday with an increasing southwest
pressure gradient over the area. Expect breezy and dry conditions
in response to this system with potential fire weather concerns,
especially across the northern sections. Consensus blends
continue to show high pressure building over the Great Basin
region through the workweek keeping the bulk of the moisture south
of the forecast area. This setup will keep a slight chance of
late-day shower and thunderstorm activity over the Four Corners
region and the higher terrain along the Continental Divide for the
remainder of the workweek with the threat of showers and
thunderstorms progressing slowly north by the end of the week.
However, stay tuned to the latest forecast since confidence is low
beyond midweek with the potential monsoon influx of moisture.
Longer range are advertising an increasing moisture surge by next
weekend. Temperatures will be running about 5 to 10 degrees above
normal through the week.

&&

.AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon)
Issued at 1130 AM MDT Fri Aug 6 2021

Strong, gusty winds are expected for all TAF sites this afternoon
and into the evening hours as a disturbance swings through.
Increasing clouds are also expected through the afternoon, along
with some showers and thunderstorms for mountain TAF sites. The
main threat with any storms that do form will be erratic, gusty
outflow winds. Winds and clouds will decrease overnight. Tomorrow
will see clear skies and winds following typical terrain driven
patterns. VFR conditions will prevail for the next 24 hours.

&&

.FIRE WEATHER...
Issued at 230 PM MDT Fri Aug 6 2021

Strong prefrontal winds in combination with already drying low
levels, critical conditions will be reached for areas with
susceptible fuels. Therefore, Red Flag Warnings for the areas
determined critical in coordination with fuel specialists will
continue. Winds taper off by 8 PM MDT with a wind shift to the
northwest occurring with frontal passage overnight.

Through the weekend, localized fire weather conditions may recur
each afternoon while high pressure remains suppressed to the
south and a series of troughs pass north of the region on Sunday.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Red Flag Warning until 8 PM MDT this evening for COZ200-202-203.

UT...Red Flag Warning until 8 PM MDT this evening for UTZ490.

&&

SHORT TERM...MPM
LONG TERM...MPM
AVIATION...BGB

Hazardous Weather Outlook
National Weather Service Grand Junction CO
453 AM MDT Fri Aug 6 2021

COZ001>014-017>023-UTZ022>025-027>029-071100-
Lower Yampa River Basin-Central Yampa River Basin-
Roan and Tavaputs Plateaus-Elkhead and Park Mountains-
Upper Yampa River Basin-Grand Valley-Debeque to Silt Corridor-
Central Colorado River Basin-Grand and Battlement Mesas-
Gore and Elk Mountains/Central Mountain Valleys-
Central Gunnison and Uncompahgre River Basin-
West Elk and Sawatch Mountains-Flat Tops-
Upper Gunnison River Valley-Uncompahgre Plateau and Dallas Divide-
Northwest San Juan Mountains-Southwest San Juan Mountains-
Paradox Valley/Lower Dolores River-
Four Corners/Upper Dolores River-Animas River Basin-
San Juan River Basin-Southeast Utah-Eastern Uinta Mountains-
Eastern Uinta Basin-Tavaputs Plateau-Arches/Grand Flat-
La Sal and Abajo Mountains-Canyonlands/Natural Bridges-
453 AM MDT Fri Aug 6 2021

This hazardous weather outlook is for eastern Utah and western
Colorado.

.DAY ONE...Today and Tonight

Hot and dry conditions combine with strong southwest winds today
leading to critical fire weather conditions across northwest and
west-central Colorado and east-central Utah. A Red Flag Warning
remains in effect for those areas from noon to 8 PM this evening.
In addition, scattered showers and thunderstorms will develop
this afternoon, though mainly over the mountains. Relatively fast
moving, high based storms are unlikely to generate heavy rain, so
the flash flood and mud/debris slide potential is low.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

 Precipitation chances remain low this weekend through the middle
of next week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Special Weather Statement
National Weather Service Grand Junction CO
333 PM MDT Fri Aug 6 2021

COZ007-008-010-013-062200-
Central Colorado River Basin CO-Flat Tops CO-
Debeque to Silt Corridor CO-
Gore and Elk Mountains/Central Mountain Valleys CO-
333 PM MDT Fri Aug 6 2021

...A strong thunderstorm will impact portions of southeastern
Garfield County through 400 PM MDT...

At 331 PM MDT, Doppler radar was tracking a strong thunderstorm over
New Castle, moving northeast at 40 mph.

HAZARD...Winds in excess of 50 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Glenwood Springs, New Castle, Silt and Shoshone.

This includes the following highways...
 Interstate 70 in Colorado between mile markers 97 and 128.
 Colorado 82 near mile marker 1.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 3944 10757 3955 10767 3977 10729 3959 10713
TIME...MOT...LOC 2131Z 240DEG 37KT 3956 10753

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

MDA

Special Weather Statement
National Weather Service Grand Junction CO
356 PM MDT Fri Aug 6 2021

COZ002-004-062245-
Elkhead and Park Mountains CO-Central Yampa River Basin CO-
356 PM MDT Fri Aug 6 2021

...A strong line of thunderstorms will impact portions of
northwestern Routt and eastern Moffat Counties through 445 PM MDT...

At 355 PM MDT, Doppler radar was tracking a line of strong
thunderstorms 10 miles south of Battle Creek Campground, moving
northeast at 40 mph.

HAZARD...Winds in excess of 40 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Craig, Great Divide, Slater, Fortification and Lay.

This includes the following highways...
 U.S. Highway 40 in Colorado between mile markers 69 and 93.
 Colorado 13 between mile markers 82 and 123.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4099 10685 4098 10687 4093 10685 4093 10682
      4090 10681 4091 10678 4090 10677 4039 10773
      4069 10819 4100 10746 4100 10686
TIME...MOT...LOC 2155Z 237DEG 37KT 4095 10720

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

TGR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
402 PM MDT FRI AUG 6 2021

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

0308 PM     NON-TSTM WND GST 16 NW MOAB              38.75N 109.75W
08/06/2021  M46 MPH          GRAND              UT   ASOS

            ASOS STATION KCNY 16 NW MOAB.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
438 PM MDT FRI AUG 6 2021

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

0423 PM     NON-TSTM WND GST 18 SE MASSADONA         40.02N 108.40W
08/06/2021  M51 MPH          RIO BLANCO         CO   MESONET

            MESONET STATION PIRC2 PINTO, MASSADONA 18SE.

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
439 PM MDT FRI AUG 6 2021

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

0352 PM     NON-TSTM WND GST 3 NNW HOTCHKISS         38.85N 107.74W
08/06/2021  M45 MPH          DELTA              CO   MESONET

            MESONET STATION JAYC2 JAY, HOTCHKISS 3NNW.

&&

Special Weather Statement
National Weather Service Grand Junction CO
449 PM MDT Fri Aug 6 2021

COZ002-004-005-013-062315-
Flat Tops CO-Upper Yampa River Basin CO-
Elkhead and Park Mountains CO-Central Yampa River Basin CO-
449 PM MDT Fri Aug 6 2021

...A strong line of thunderstorms will impact portions of northern
Routt and southeastern Moffat Counties through 515 PM MDT...

At 448 PM MDT, Doppler radar was tracking a strong line
of thunderstorms 7 miles north of Craig, moving northeast at 45 mph.

HAZARD...Winds in excess of 45 mph.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Craig, Steamboat Springs, Hayden, Clark, Milner, Tow Creek, Hamilton
and Hahns Peak.

This includes the following highways...
 U.S. Highway 40 in Colorado between mile markers 80 and 127.
 Colorado 13 between mile markers 70 and 114.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4096 10687 4093 10685 4058 10670 4023 10766
      4072 10783 4101 10696 4100 10688
TIME...MOT...LOC 2248Z 241DEG 40KT 4062 10758

MAX HAIL SIZE...0.00 IN
MAX WIND GUST...40 MPH

TGR