Flash Flood Warning 6, NWS Denver/Boulder, CO

342 
WGUS75 KBOU 032244
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
444 PM MDT Sun Jul 3 2022

COC013-040115-
/O.CON.KBOU.FF.W.0006.000000T0000Z-220704T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Boulder CO-
444 PM MDT Sun Jul 3 2022

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 715 PM MDT THIS 
EVENING FOR NORTH CENTRAL BOULDER COUNTY...

At 444 PM MDT, Doppler radar and automated rain gauges indicated 
heavy rain had fallen across the warned area. Between 0.5 and 0.75 
inches of rain has fallen. Flash flooding is ongoing or expected to 
begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar and automated gauges.

IMPACT...Flash flooding of small creeks and streams, gulches,
         roads, and poor drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Jamestown and the Calwood burn area.

This includes the following streams and drainages...
  Little James Creek, South Saint Vrain Creek, Left Hand Creek, 
  Middle Saint Vrain Creek, Dry Creek, Saint Vrain Creek and North 
  Saint Vrain Creek.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Move to higher ground now. Act quickly to protect your life.

Heavy rainfall will cause flash flooding of creeks, streams, and 
ditches in the Calwood burn area. Rock slides or debris flows can 
also be expected. The main areas of concern are Heil Valley Ranch 
and Lefthand Creek just above US 36.

&&

LAT...LON 4019 10539 4020 10523 4010 10525 4010 10536
      4013 10541

FLASH FLOOD...RADAR AND GAUGE INDICATED

$$

RPK

943 
WGUS75 KBOU 032325
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
525 PM MDT Sun Jul 3 2022

COC013-032335-
/O.CAN.KBOU.FF.W.0006.000000T0000Z-220704T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Boulder CO-
525 PM MDT Sun Jul 3 2022

...FLASH FLOOD WARNING IS CANCELLED FOR NORTH CENTRAL BOULDER 
COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4019 10539 4020 10523 4010 10525 4010 10536
      4013 10541

$$

RPK

Area Forecast Discussion
National Weather Service Denver/Boulder CO
245 PM MDT Sun Jul 3 2022

.SHORT TERM...(This evening through Monday)
Issued at 140 PM MDT Sun Jul 3 2022

Weak showers and storms are coming up over the mountains and not
yet quite able to move off the terrain. Continue to expect another
afternoon of generally weak convection with scattered to
widespread showers over the mountains and more isolated over the
plains in the late afternoon and early evening. The main impact
will be variable gusts with passing storms but there is still a
limited threat of burn area flash flooding as a few stronger or
slower showers pass by the scars. Convection will diminish through
the evening, then partly cloudy to mostly clear skies and near
normal temperatures tonight.

Tomorrow, a similar synoptic situation as the ridge stalls and
broadens a bit. Temperatures will warm a few more degrees,
bringing highs up to the low 90s to near 100 across the plains
(warmest in the northeast corner), 70s and 80s in the foothills
and mountain valleys, and 50s and 60s in the mountains. Expect
another round of afternoon convection similar to today, though
with a bit less moisture and instability and maybe slightly faster
storm motions. Precipitation will favor the southern Front Range
and Palmer Divide, but there will be a limited threat of burn area
flashing flooding.

.LONG TERM...(Monday night through Sunday)
Issued at 240 PM MDT Sun Jul 3 2022

Weak southwesterly flow aloft will be in place over the forecast
area Monday night through Wednesday night as upper ridging remains
located southeast of the CWA. The ridge axis is still expected to
push westward a bit on Wednesday and Wednesday night. There is
weak upward vertical velocity over the CWA through Wednesday
night according to the QG Omega fields. Looking at the available
moisture, precipitable water values range from 0.70 inch west to
1.40 inches east for the CWA Monday night through Wednesday night.
There is decent CAPE progged over the mountains and foothills
Monday evening and both late day periods on Tuesday and Wednesday.
There is little CAPE to work with over the plains Monday night
and Tuesday, then there is an increase for Wednesday.

Again, will keep the higher pops in the mountains and foothills
through the periods with 10-30%s over the plains late day Tuesday
and 20-40%s over the plains late day Wednesday. For rainfall, the
QPF fields show the highest measurable rainfall amounts over the
mountains and foothills through the periods, although nothing
significant. There is even less measurable rainfall progged over
the plains, with the higher amounts noted on Wednesday. The
temperature and thickness fields continue to show the afternoon high
temperatures above seasonal normals Tuesday and Wednesday.

For the later days, Thursday through Sunday, medium range models
still have a weak upper trough over Colorado on Thursday and then
an upper ridge axis right over the state Friday through Sunday.
The best moisture Will be around Thursday and Friday with some
drying Saturday and Sunday. Thickness fields continue to indicate
temperatures above normal, with Saturday and Sunday to be the
hottest days.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 1008 AM MDT Sun Jul 3 2022

Expect VFR conditions through the TAF period. A weak cyclone is
keeping winds westerly to northwesterly this morning, then winds
should come around northeasterly in the afternoon. Convection will
initiate over the high terrain by early afternoon and storms may
be in the vicinity by around 20z. Storms will bring mostly just
variable and gusty winds, but brief reductions in ceiling and
visibility are possible. Convection will decrease through the
evening then drainage winds likely again tonight. Expect a similar
situation again tomorrow.

&&

.HYDROLOGY...
Issued at 240 PM MDT Sun Jul 3 2022

Today, a limited threat of burn area flash flooding will persist
through the early evening. A few advisories and a warning have
already been issued.

Monday, expect another round of afternoon showers and storms but
with less coverage. Precipitation will favor the southern Front
Range and Palmer Divide but there will still be a limited threat
of burn area flash flooding.

There will be a threat of burn scar flooding over the mountains
and foothills during the afternoons and evenings all of next week;
more so on Tuesday, Wednesday and Thursday.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&

SHORT TERM....EJD
LONG TERM.....RJK
AVIATION......EJD
HYDROLOGY.....EJD/RJK

Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1053 AM MDT Sun Jul 3 2022

COZ030>051-041700-
Jackson County Below 9000 Feet-
West Jackson and West Grand Counties Above 9000 Feet-
Grand and Summit Counties Below 9000 Feet-
South and East Jackson/Larimer/North and Northeast Grand/
Northwest Boulder Counties Above 9000 Feet-
South and Southeast Grand/West Central and Southwest Boulder/
Gilpin/Clear Creek/Summit/North and West Park Counties Above
9000 Feet-Larimer and Boulder Counties Between 6000 and 9000 Feet-
Jefferson and West Douglas Counties Above 6000 Feet/Gilpin/Clear
Creek/Northeast Park Counties Below 9000 Feet-
Central and Southeast Park County-
Larimer County Below 6000 Feet/Northwest Weld County-
Boulder And Jefferson Counties Below 6000 Feet/West Broomfield
County-
North Douglas County Below 6000 Feet/Denver/West Adams and
Arapahoe Counties/East Broomfield County-
Elbert/Central and East Douglas Counties Above 6000 Feet-
Northeast Weld County-Central and South Weld County-Morgan County-
Central and East Adams and Arapahoe Counties-
North and Northeast Elbert County Below 6000 Feet/North Lincoln
County-
Southeast Elbert County Below 6000 Feet/South Lincoln County-
Logan County-Washington County-Sedgwick County-Phillips County-
1053 AM MDT Sun Jul 3 2022

This hazardous weather outlook is for northeast and north central
Colorado.

.DAY ONE...Today and Tonight

Scattered thunderstorms are expected this afternoon across
northeast Colorado, with the best chance for rain along the Front
Range and into South Park and the Palmer Divide. A few strong
storms are possible over far northeastern Colorado, with gusty
winds and hail as the main threats. There is a limited threat
of burn area flash flooding.

.DAYS TWO THROUGH SEVEN...Monday through Saturday

Scattered late day showers and thunderstorms are expected in the
mountains and foothills Monday through next Saturday and over the
plains on Wednesday and Thursday. The other days, the plains can
expect a slight chance of late day storms. There will continue to
be a limited threat of alpine burn scar flash flooding due to the
rainfall.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

Special Weather Statement
National Weather Service Denver CO
351 PM MDT Sun Jul 3 2022

COZ035-032215-
Larimer and Boulder Counties Between 6000 and 9000 Feet CO-
351 PM MDT Sun Jul 3 2022

...A strong thunderstorm will impact portions of central Boulder
County through 415 PM MDT...

At 351 PM MDT, Doppler radar was tracking a strong thunderstorm over
Jamestown, or 35 miles northwest of Denver, moving northeast at 10
mph.

HAZARD...Wind gusts up to 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...
Northwestern Boulder, Jamestown, Raymond, Wallstreet, Salina,
Crisman, Gold Hill, Sunshine, Summerville, Peaceful Valley and
Allenspark.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Prepare for sudden gusty winds. Secure loose objects and move to a
safe shelter inside a building or vehicle.

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 4021 10536 4013 10531 4012 10531 4012 10530
      4009 10529 4007 10529 4007 10531 4004 10530
      4000 10543 4007 10547 4008 10547 4009 10548
      4014 10551 4016 10550
TIME...MOT...LOC 2151Z 240DEG 9KT 4010 10541

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...50 MPH

RPK