Alert archive / Colorado / Flash Flood Warnings in 2018

Flash Flood Warning 5, NWS Denver/Boulder, CO

June 19, 2018Morgan County, Weld County, Colorado

NWS Denver/Boulder, CO issued this flash flood warning at Jun 19, 2018, 2:36 PM MDT for Morgan County, Weld County, Colorado. It was in force for 114 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jun 19, 2018, 2:36 PM MDT (20:36 UTC)
Expired
Jun 19, 2018, 4:30 PM MDT
In force
114 min
Issued by
NWS Denver/Boulder, CO
Area
Storm-based polygon
Flood severity
None

Counties Morgan County, CO, Weld County, CO

The radar

The Denver radar (KFTG), 41 km from the middle of the area, began a volume at 20:39 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Denver, CO (KDEN), launched 12:00Z, 8.6 hours before the alert went out and 92 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Denver, CO at 12:00Z on 2018-06-19Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 30 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2018-06-19The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 70 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
30 J/kg
Mixed-layer CIN
-220 J/kg
Mixed-layer LCL
836 m above ground
0-6 km bulk shear
53 kt
0-1 km storm-relative helicity
70 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

316 
WGUS55 KBOU 192036
FFWBOU
COC087-123-192230-
/O.NEW.KBOU.FF.W.0005.180619T2036Z-180619T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Denver CO
236 PM MDT TUE JUN 19 2018

The National Weather Service in Denver Colorado has issued a

* Flash Flood Warning for...
  South central Weld County in northeastern Colorado...
  Southwestern Morgan County in northeastern Colorado...

* Until 430 PM MDT.

* At 235 PM MDT, Doppler radar indicated thunderstorms producing
  heavy rain 9 miles west of Hoyt. The rain is moving east at 25 mph.
  Up to one inch of rain has already fallen, on top of several 
  inches that fell last night. Flash flooding is expected to begin 
  shortly.

* Some locations that will experience flooding include...
  Prospect Valley, Hoyt and Roggen. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 4003 10448 4017 10447 4020 10400 4001 10393

$$

GIMMESTAD
2 follow-up statements
633 
WGUS75 KBOU 192157
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
357 PM MDT TUE JUN 19 2018

COC087-123-192230-
/O.CON.KBOU.FF.W.0005.000000T0000Z-180619T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-Morgan CO-
357 PM MDT TUE JUN 19 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM MDT FOR
SOUTH CENTRAL WELD AND SOUTHWESTERN MORGAN COUNTIES...

Although the thunderstorm producing heavy rain had moved east of the 
warned area, there could still be residual flooding. Up to an inch 
of rain fell this afternoon in this same area where flooding 
occurred Monday night.

Some locations that will experience flooding include...
Prospect Valley, Hoyt and Roggen. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, country roads, farmland, and other low lying
spots.

&&

LAT...LON 4003 10448 4017 10447 4020 10400 4001 10393

$$

TH
178 
WGUS75 KBOU 192234
FFSBOU

Flash Flood Statement
National Weather Service Denver CO
434 PM MDT TUE JUN 19 2018

COC087-123-192239-
/O.EXP.KBOU.FF.W.0005.000000T0000Z-180619T2230Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Weld CO-Morgan CO-
434 PM MDT TUE JUN 19 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL WELD AND SOUTHWESTERN
MORGAN COUNTIES WILL EXPIRE AT 430 PM MDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Drivers in the area around Prospect Valley and Hoyt should 
be alert for areas of erosion on rural roads.

LAT...LON 4003 10448 4017 10447 4020 10400 4001 10393

$$

GIMMESTAD

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Denver/Boulder, CO wrote its last area forecast discussion before this flash flood warning went out at Jun 19, 10:23 AM MDT, 4 hours 13 minutes earlier.

Area forecast discussion, Jun 19, 10:23 AM MDT, 4 hours 13 minutes before
Area Forecast Discussion
National Weather Service Denver/Boulder CO
1023 AM MDT Tue Jun 19 2018

.UPDATE...
Issued at 1023 AM MDT Tue Jun 19 2018

Dissipating stratus has allowed for warmer temperatures already
this morning, have increased the max temperatures expected today.
This may mean more instability for storms, however viewing recent
ACARS data, there is quite a cap of warmer temperatures around
650mb which will need to be cooled with the incoming shortwave
trough to break through.

First cell already up over northwestern Boulder County, which has
been advertised by several CAMs, including the experimental HRRR
and the NAM-Nest. Still don't like how the HRRR and experimental
HRRR keeps the Denver metro area over into DIA clear through the
afternoon, but at least they are showing an uptick of convection
occurring to the north and south.

UPDATE Issued at 805 AM MDT Tue Jun 19 2018

Areas of stratus are breaking up and dispersing over the plains
slightly earlier than expected, but other areas are getting
thicker, and there is no clear trend of what will happen. But any
warming will add to our CAPE amounts expected later today. With
the shortwave trough over Utah very pronounced in satellite
imagery, expected to pass over at peak heating, believe we are
well on track to see more severe weather today. CAMs continue to
have different ideas on the timing, likely influenced on the
messy/inconclusive conditions that will occur this morning into
the afternoon. Some have a batch forming over the Palmer Divide
and Northern mountains near or just after pushing east to affect
the metro area around 2pm, then pushing southeast. Other solutions
show activity holding off over the mountains until around 2pm,
then only affecting the northern state border and Palmer Divide
through the afternoon, keeping the metro area and points east
clear until later tonight around 9pm. Since the current HRRR runs
keep a low stratus layer over Denver through early afternoon, yet
on satellite this stratus is breaking up already, confidence in
timing and location is marginal at best in this solution, as well
as all others due to the completely different timing between them
all. Confidence in seeing severe weather somewhere in our area
however remains high, with CAPE values of 2000+ J/kg and the upper
shortwave coming in. SPC has increased the risk of severe weather
over the Palmer Divide to an Enhanced Risk, meaning numerous
severe storms are expected, and agree with this. Large hail and
strong winds will again be the main threat, and even though we
don't have the Denver Cyclone today to help with potential spin up
of landspout tornadoes, bulk shear of 35 to 50 kts will provide a
chance for a tornadoes as well.

Will have to keep an eye on storm coverage along and north of I76
where radar estimates of 4 to 6 inches of rain fell over that area
last night. With potential soaked soils, any storm may cause some
flooding issues sooner than normal over that area. Keeping an eye
on river levels along the South Platte as well due to last nights
rains flowing and draining northeast downriver along the South
Platte, mainly from southeastern Weld out into Nebraska. So far,
river levels have increased 1-3 feet, but it's not toward any
action stage, so no highlights are needed.

&&

.SHORT TERM...(Today and tonight)
Issued at 329 AM MDT Tue Jun 19 2018

...MAIN CONCERN TODAY IS ANOTHER POSSIBLE ROUND OF SEVERE
WEATHER...

Last night's impressive round of severe convection and heavy
rainfall is finally waning in the early morning hours. There is
still some mid level instability and upper level support this
morning as 85+ knot upper level speed max rotates around the
base of the trough to our west. This can be seen nicely in the Q-G
fields, with pretty healthy lift for this time of year. As a
result, can't rule out a couple showers/storms lingering over the
northern areas this morning. Otherwise, we'll see shallow and very
moist upslope flow keep areas of light drizzle, low clouds, and
even some fog in place from the foothills east across the plains
through mid morning.

This afternoon and evening's severe weather threat will depend on
how much heating and destabilization we can get. The stratus and
light drizzle will definitely delay the heating, but at the same
time, the upper level support and couple degrees of cooling aloft
will aid destabilization. Even the cooler NAM with a 72/58
provides us with 2000 J/kg of CAPE, but still about 20 J/kg of
Convective Inhibition (CIN) to overcome. Still not sure if we'll
get that warm. If there was not any upper level support, we'd be
capped off across the plains, but given the short wave and upper
level lift, I would not be surprised to see strong to severe
convection originate over the higher terrain of the foothills and
Palmer Divide/Cheyenne Ridge by early afternoon, and then attempt
to spread across the plains and portions of the I-25 Corridor late
this afternoon and early evening. Any storms that are able to
capture the higher instability are likely to become severe with
large hail, damaging winds, and even a tornado or two given the
relatively low LCL. It should be worth noting the High Resolution
Ensembles (HREF) are also struggling with this tug-of-war between
instability and the cap, with many variable solutions regarding
today's severe weather threat. SPC has a slight risk of storms
over the I-25 Corridor and plains and this looks good for now. We
can refine through the day depending on stratus coverage and
available daytime heating/destabilization.

The main threat of severe weather would shift rather quickly east
across the plains this evening as the upper level support shifts
that way. We don't expect another all night weather event given
the subsidence moving in from the west and downslope component
developing just off the deck.

.LONG TERM...(Wednesday through Monday)
Issued at 329 AM MDT Tue Jun 19 2018

The upper level trough over the nrn Rockies will move southeast into
the central US on Wed and then move slowly eastward on Thu.  NW flow
aloft will be over nrn CO on Wed and then become more WNW on Thu.
Cross-sections do not show much moisture across the area either day
with limited instability.  Thus tstm coverage will be in the isold-
wdly sct range.  As far as temps, readings will remain below normal
across nern CO with readings in the upper 60s to mid 70s on Wed.  By
Thu readings will warm into the mid 70s to lower 80s across the
plains.

On Fri an upper level trough will move across the nrn Rockies with
the flow aloft remaining WNW.  At the sfc, a lee trough will develop
over ern CO with southerly low level flow.  Instability is fcst to
improve some on Fri with capes in the 500-1000 j/kg over the ern
plains so will leave in a slight chc of storms.  Over the higher
terrain it looks dry.  Highs on Fri will be in the 80s across nern
CO.

On Sat mainly dry NW flow aloft will be over the area with a sfc lee
trough remaining over ern CO. At this time instability and
moisture appear limited so any tstms will be rather isold. As for
highs readings will stay in the 80s across nern CO.

For Sun a rather stg upper level trough for late June will move into
the nrn and central Rockies.  The ECMWF has this feature centered
over WY while the GFS is further south over CO.  Depending on where
this feature ends up it could bring a decent chc of pcpn to portions
of the area especially across the plains.

&&

.AVIATION...(For the 12Z TAFS through 12Z Tuesday night)
Issued at 805 AM MDT Tue Jun 19 2018

Ceilings have improved faster than forecasted by us or other
models, and only have some IFR to MVFR ceilings left with even VFR
near DEN. The additional heating may help boost forecasted
thunderstorm development and possible severe weather. Any storms
that do develop will be capable of becoming severe with large hail
the primary threat, but also gusty winds of 40-50 knots possible.
Main period of thunderstorms for the Front Range airports should
be 21Z-02Z, but there may be another period after 03z. Then look
for partial clearing but shallow upslope flow may keep some
stratus/light fog in play later tonight.

&&

.HYDROLOGY...
Issued at 329 AM MDT Tue Jun 19 2018

Flash flooding across portions of eastern Weld/NW Morgan
counties should be winding down through early morning as rain has
decreased significantly, and will address the lingering short
term hydro concerns with follow-up statements as needed. For this
afternoon and evening, storms should be moving along at a decent
clip near 20-25 mph, and training storms aren't anticipated like
last night. They will be strong to severe and capable of
producing very heavy rain, but given the expected movement we
won't be issuing a Flash Flood Watch at this time.

&&

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

UPDATE...Kriederman
SHORT TERM...Barjenbruch
LONG TERM...RPK
AVIATION...Barjenbruch/Kriederman
HYDROLOGY...Barjenbruch
Hazardous weather outlook, Jun 19, 10:49 AM MDT, 3 hours 47 minutes before
Hazardous Weather Outlook
National Weather Service Denver/Boulder CO
1049 AM MDT Tue Jun 19 2018

COZ030>051-201700-
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-
1049 AM MDT Tue Jun 19 2018

...SEVERE WEATHER EXPECTED AGAIN FOR THE PLAINS THIS AFTERNOON
AND EVENING...

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

.DAY ONE...Today and Tonight

Another round of strong to severe thunderstorms is likely this
afternoon and evening across the plains. Look for scattered
thunderstorms to develop across the higher terrain, including the
Foothills, Palmer Divide, and Cheyenne Ridge area by noon. Those
storms will develop and move east across the plains early this
afternoon and evening. Large hail up to 2 inches in diameter,
damaging winds of 60 mph or more, and even a couple tornadoes will
be possible from the stronger storms. Heavy rain will also be an
impact, causing localized flooding problems over urban areas with
poor drainage, low lying areas, and potentially over southeastern
Weld County into northwesterly Morgan County where 4 to 6 inches
of rain fell last night.

Outflow and a cool front will push down from the north this
evening to likely keep some storms going and may even bring a
second round to the area mid-evening. Storms are then expected to
decrease from west to east across the plains around midnight.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Drier weather will return for Wednesday through Saturday with
only a slight chance of thunderstorms in the afternoon and
evening. A weather system may affect the area by Sunday bringing
a better chance of thunderstorms.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be required by 1 PM.

In the hours before

Local storm report, Jun 19, 1:51 PM MDT, 45 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
151 PM MDT TUE JUN 19 2018

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

0149 PM     HAIL             HUDSON                  40.07N 104.64W
06/19/2018  M1.25 INCH       WELD               CO   TRAINED SPOTTER

0139 PM     HAIL             3 S AURORA              39.66N 104.81W
06/19/2018  M1.25 INCH       ARAPAHOE           CO   PUBLIC

0125 PM     HAIL             DENVER                  39.77N 104.87W
06/19/2018  M1.75 INCH       DENVER             CO   COCORAHS

0125 PM     HAIL             CENTENNIAL              39.65N 104.99W
06/19/2018  M3.00 INCH       ARAPAHOE           CO   COCORAHS

0115 PM     HAIL             1 E GREENWOOD VILLAGE   39.61N 104.89W
06/19/2018  E2.00 INCH       ARAPAHOE           CO   PUBLIC

0107 PM     HAIL             2 S LAKEWOOD            39.67N 105.11W
06/19/2018  E1.00 INCH       JEFFERSON          CO   AMATEUR RADIO

0105 PM     HAIL             LITTLETON               39.59N 105.01W
06/19/2018  M1.75 INCH       ARAPAHOE           CO   COCORAHS

0104 PM     HAIL             LITTLETON               39.59N 105.01W
06/19/2018  M1.75 INCH       ARAPAHOE           CO   PUBLIC

0101 PM     HAIL             3 S LAKEWOOD            39.66N 105.10W
06/19/2018  M1.00 INCH       JEFFERSON          CO   PUBLIC

0101 PM     HAIL             2 N SHERIDAN            39.68N 105.03W
06/19/2018  E1.00 INCH       DENVER             CO   TRAINED SPOTTER

0100 PM     HAIL             1 W FIRESTONE           40.12N 104.96W
06/19/2018  E1.25 INCH       WELD               CO   PUBLIC

0100 PM     HAIL             GREELEY                 40.42N 104.74W
06/19/2018  M1.00 INCH       WELD               CO   TRAINED SPOTTER

1258 PM     HAIL             1 W FIRESTONE           40.12N 104.96W
06/19/2018  M1.50 INCH       WELD               CO   PUBLIC

1255 PM     HAIL             7 SSE VIRGINIA DALE     40.86N 105.30W
06/19/2018  M2.00 INCH       LARIMER            CO   COCORAHS

1250 PM     HAIL             3 WNW NIWOT             40.11N 105.21W
06/19/2018  M1.50 INCH       BOULDER            CO   COCORAHS

1247 PM     HAIL             LITTLETON               40.95N 105.46W
06/19/2018  M1.75 INCH       LARIMER            CO   COCORAHS

            BROKEN HOUSE WINDOWS.

1243 PM     HAIL             2 S LONGMONT            40.14N 105.11W
06/19/2018  M1.25 INCH       BOULDER            CO   PUBLIC

1240 PM     HAIL             3 WNW NIWOT             40.11N 105.21W
06/19/2018  M1.00 INCH       BOULDER            CO   COCORAHS

1218 PM     HAIL             2 WNW NIWOT             40.11N 105.19W
06/19/2018  M1.00 INCH       BOULDER            CO   COCORAHS

&&
Local storm report, Jun 19, 2:05 PM MDT, 31 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
205 PM MDT TUE JUN 19 2018

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

0149 PM     HAIL             HUDSON                  40.07N 104.64W
06/19/2018  M1.25 INCH       WELD               CO   TRAINED SPOTTER

0147 PM     HAIL             2 NNE BUCKLEY AFB       39.72N 104.74W
06/19/2018  E1.00 INCH       ARAPAHOE           CO   AMATEUR RADIO

0140 PM     HAIL             5 E CHERRY CREEK RESER  39.62N 104.78W
06/19/2018  E2.50 INCH       ARAPAHOE           CO   TRAINED SPOTTER

            1.75 TO 2 INCH HAIL.

0139 PM     HAIL             3 S AURORA              39.66N 104.81W
06/19/2018  M1.25 INCH       ARAPAHOE           CO   PUBLIC

0125 PM     HAIL             CENTENNIAL              39.65N 104.99W
06/19/2018  M3.00 INCH       ARAPAHOE           CO   COCORAHS

0125 PM     HAIL             DENVER                  39.77N 104.87W
06/19/2018  M1.75 INCH       DENVER             CO   COCORAHS

0122 PM     HAIL             1 NNW FORT LUPTON       40.10N 104.81W
06/19/2018  E1.00 INCH       WELD               CO   TRAINED SPOTTER

0115 PM     HAIL             2 S ENGLEWOOD           39.62N 104.99W
06/19/2018  E1.00 INCH       ARAPAHOE           CO   AMATEUR RADIO

0115 PM     HAIL             1 E GREENWOOD VILLAGE   39.61N 104.89W
06/19/2018  E2.00 INCH       ARAPAHOE           CO   PUBLIC

0112 PM     HAIL             GREELEY                 40.42N 104.74W
06/19/2018  M1.75 INCH       WELD               CO   EMERGENCY MNGR

0107 PM     HAIL             2 S LAKEWOOD            39.67N 105.11W
06/19/2018  E1.00 INCH       JEFFERSON          CO   AMATEUR RADIO

0105 PM     HAIL             LITTLETON               39.59N 105.01W
06/19/2018  M1.75 INCH       ARAPAHOE           CO   COCORAHS

0104 PM     HAIL             LITTLETON               39.59N 105.01W
06/19/2018  M1.75 INCH       ARAPAHOE           CO   PUBLIC

0101 PM     HAIL             2 N SHERIDAN            39.68N 105.03W
06/19/2018  E1.00 INCH       DENVER             CO   TRAINED SPOTTER

0101 PM     HAIL             3 S HYGIENE             40.14N 105.16W
06/19/2018  E1.25 INCH       BOULDER            CO   NWS EMPLOYEE

0101 PM     HAIL             3 S LAKEWOOD            39.66N 105.10W
06/19/2018  M1.00 INCH       JEFFERSON          CO   PUBLIC

0100 PM     HAIL             1 W FIRESTONE           40.12N 104.96W
06/19/2018  E1.25 INCH       WELD               CO   PUBLIC

0100 PM     HAIL             GREELEY                 40.42N 104.74W
06/19/2018  M1.00 INCH       WELD               CO   TRAINED SPOTTER

1258 PM     HAIL             1 W FIRESTONE           40.12N 104.96W
06/19/2018  M1.50 INCH       WELD               CO   PUBLIC

1255 PM     HAIL             3 W GREELEY             40.42N 104.80W
06/19/2018  M1.50 INCH       WELD               CO   NWS EMPLOYEE

1255 PM     HAIL             7 SSE VIRGINIA DALE     40.86N 105.30W
06/19/2018  M2.00 INCH       LARIMER            CO   COCORAHS

1250 PM     HAIL             3 WNW NIWOT             40.11N 105.21W
06/19/2018  M1.50 INCH       BOULDER            CO   COCORAHS

1247 PM     HAIL             LITTLETON               40.95N 105.46W
06/19/2018  M1.75 INCH       LARIMER            CO   COCORAHS

            BROKEN HOUSE WINDOWS.

1243 PM     HAIL             2 S LONGMONT            40.14N 105.11W
06/19/2018  M1.25 INCH       BOULDER            CO   PUBLIC

1240 PM     HAIL             3 WNW NIWOT             40.11N 105.21W
06/19/2018  M1.00 INCH       BOULDER            CO   COCORAHS

1218 PM     HAIL             2 WNW NIWOT             40.11N 105.19W
06/19/2018  M1.00 INCH       BOULDER            CO   COCORAHS

&&
Local storm report, Jun 19, 2:07 PM MDT, 29 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
207 PM MDT TUE JUN 19 2018

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

0206 PM     HAIL             2 SSW ARAPAHOE PARK     39.61N 104.71W
06/19/2018  M2.75 INCH       ARAPAHOE           CO   PUBLIC

&&
Local storm report, Jun 19, 2:19 PM MDT, 17 minutes before
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE DENVER CO
219 PM MDT TUE JUN 19 2018

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

0211 PM     HAIL             3 NW CHERRY CREEK RESER 39.67N 104.90W
06/19/2018  E0.50 INCH       ARAPAHOE           CO   TRAINED SPOTTER

0206 PM     HAIL             2 SSW ARAPAHOE PARK     39.61N 104.71W
06/19/2018  M2.75 INCH       ARAPAHOE           CO   PUBLIC

0200 PM     HAIL             11-MILE CANYON RESERVOI 38.90N 105.48W
06/19/2018  M2.75 INCH       PARK               CO   NWS EMPLOYEE

0200 PM     HAIL             AURORA                  39.70N 104.81W
06/19/2018  M2.50 INCH       ARAPAHOE           CO   NWS EMPLOYEE

            AURORA RESERVOIR.

0135 PM     HAIL             2 E CENTENNIAL          39.60N 104.83W
06/19/2018  M1.00 INCH       ARAPAHOE           CO   PUBLIC

0130 PM     HAIL             GREENWOOD VILLAGE       39.62N 104.92W
06/19/2018  M2.75 INCH       ARAPAHOE           CO   NWS EMPLOYEE

0126 PM     HAIL             2 NE CHERRY HILLS VILLA 39.66N 104.91W
06/19/2018  M0.50 INCH       DENVER             CO   PUBLIC

0125 PM     HAIL             5 E CHERRY CREEK RESER  39.62N 104.79W
06/19/2018  M1.25 INCH       ARAPAHOE           CO   PUBLIC

&&
Local storm report, Jun 19, 2:25 PM MDT, 11 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
225 PM MDT TUE JUN 19 2018

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

0222 PM     HAIL             1 WSW WELLINGTON        40.70N 105.02W
06/19/2018  M1.50 INCH       LARIMER            CO   AMATEUR RADIO

&&
Local storm report, Jun 19, 2:35 PM MDT, 1 minute before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DENVER CO
235 PM MDT TUE JUN 19 2018

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

0219 PM     TORNADO          4 SE PROSPECT VALLEY    40.03N 104.36W
06/19/2018                   WELD               CO   TRAINED SPOTTER

            ROPE TORNADO ON THE GROUND FOR APPROXIMATELY
            3 MINUTES.

0200 PM     HAIL             AURORA                  39.70N 104.81W
06/19/2018  M2.50 INCH       ARAPAHOE           CO   NWS EMPLOYEE

            AURORA RESERVOIR.

0200 PM     HAIL             11-MILE CANYON RESERVOI 38.90N 105.48W
06/19/2018  M2.75 INCH       PARK               CO   NWS EMPLOYEE

0130 PM     HAIL             GREENWOOD VILLAGE       39.62N 104.92W
06/19/2018  M2.75 INCH       ARAPAHOE           CO   NWS EMPLOYEE

1130 AM     HEAVY RAIN       HENDERSON               39.92N 104.87W
06/19/2018  M0.07 INCH       ADAMS              CO   MESONET

            MESONET STATION HNDC2, HENDERSON.

1100 AM     HEAVY RAIN       2 WNW ALMA              39.30N 106.11W
06/19/2018  M0.10 INCH       PARK               CO   MESONET

            MESONET STATION BUCC2, 2 WNW ALMA.

1100 AM     HEAVY RAIN       4 ESE MT ZIRKEL         40.79N 106.60W
06/19/2018  M0.20 INCH       JACKSON            CO   MESONET

            MESONET STATION ZIRC2, 4 ESE MT ZIRKEL.

1100 AM     HEAVY RAIN       3 SW WARD               40.04N 105.54W
06/19/2018  M0.20 INCH       BOULDER            CO   MESONET

            MESONET STATION NIWC2, 3 SW WARD.

1100 AM     HEAVY RAIN       5 WSW GRAND LAKE        40.23N 105.92W
06/19/2018  M0.50 INCH       GRAND              CO   MESONET

            MESONET STATION SCSC2, 5 WSW GRAND LAKE.

1100 AM     HEAVY RAIN       8 SE RAND               40.35N 106.09W
06/19/2018  M0.20 INCH       GRAND              CO   MESONET

            MESONET STATION WLLC2, 8 SE RAND.

1100 AM     HEAVY RAIN       1 SSE LOVELAND PASS     39.65N 105.87W
06/19/2018  M0.10 INCH       SUMMIT             CO   MESONET

            MESONET STATION GZPC2, 1 SSE LOVELAND PASS.

1100 AM     HEAVY RAIN       5 NNW TRAIL RIDGE       40.51N 105.77W
06/19/2018  M0.20 INCH       LARIMER            CO   MESONET

            MESONET STATION LRVC2, 5 NNW TRAIL RIDGE.

1100 AM     HEAVY RAIN       3 S LONG'S PEAK         40.20N 105.60W
06/19/2018  M0.20 INCH       BOULDER            CO   MESONET

            MESONET STATION WLBC2, 3 S LONG'S PEAK.

1100 AM     HEAVY RAIN       8 SSE GOULD             40.40N 105.96W
06/19/2018  M0.10 INCH       JACKSON            CO   MESONET

            MESONET STATION NEVC2, 8 SSE GOULD.

1000 AM     HEAVY RAIN       7 SSE SPICER            40.35N 106.38W
06/19/2018  M0.10 INCH       GRAND              CO   MESONET

            MESONET STATION ARPC2, 7 SSE SPICER.

&&

The office that day

Everything else NWS Denver/Boulder, CO issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 18, 6:12 PM MDTSevere Thunderstorm WarningBOUBoulder, Broomfield, Weld48 min
Jun 18, 6:48 PM MDTSevere Thunderstorm WarningBOUWeld42 min
Jun 18, 6:59 PM MDTSevere Thunderstorm WarningBOUWeld31 min
Jun 18, 7:19 PM MDTSpecial Weather StatementBOUBroomfield26 min
Jun 18, 7:23 PM MDTSevere Thunderstorm WarningBOUWeld52 min
Jun 18, 7:24 PM MDTSevere Thunderstorm WarningBOUAdams, Boulder, Broomfield, Weld51 min
Jun 18, 7:29 PM MDTSevere Thunderstorm WarningBOUWeld46 min
Jun 18, 8:02 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld28 min
Jun 18, 8:06 PM MDTSevere Thunderstorm WarningBOUWeld39 min
Jun 18, 8:16 PM MDTSevere Thunderstorm WarningBOUAdams, Boulder, Broomfield, Denver, Jefferson29 min
Jun 18, 8:27 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld33 min
Jun 18, 8:40 PM MDTSevere Thunderstorm WarningBOUWeld50 min
Jun 18, 8:44 PM MDTSevere Thunderstorm WarningBOUAdams, Broomfield, Weld46 min
Jun 18, 9:17 PM MDTSevere Thunderstorm WarningBOUMorgan28 min
Jun 18, 9:19 PM MDTSevere Thunderstorm WarningBOUWeld26 min
Jun 18, 9:28 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld32 min
Jun 18, 9:41 PM MDTSevere Thunderstorm WarningBOUWeld49 min
Jun 18, 9:42 PM MDTSevere Thunderstorm WarningBOULogan, Morgan, Washington48 min
Jun 18, 9:59 PM MDTSevere Thunderstorm WarningBOUMorgan31 min
Jun 18, 10:05 PM MDTAreal Flood AdvisoryBOUMorgan, Weld2 hr
Jun 18, 10:23 PM MDTSevere Thunderstorm WarningBOULogan, Washington37 min
Jun 18, 10:24 PM MDTSevere Thunderstorm WarningBOUMorgan51 min
Jun 18, 10:49 PM MDTSevere Thunderstorm WarningBOUWeld41 min
Jun 18, 10:57 PM MDTFlash Flood WarningBOUMorgan, Weld3 hr
Jun 18, 10:57 PM MDTSevere Thunderstorm WarningBOULogan, Phillips, Washington33 min
Jun 18, 11:24 PM MDTSevere Thunderstorm WarningBOULogan, Phillips39 min
Jun 18, 11:32 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld43 min
Jun 18, 11:58 PM MDTSevere Thunderstorm WarningBOULogan, Washington25 min
Jun 19, 1:11 AM MDTFlash Flood WarningBOUMorgan, Weld5 hr
Jun 19, 12:06 PM MDTSevere Thunderstorm WarningBOUBoulder24 min
Jun 19, 12:29 PM MDTSevere Thunderstorm WarningBOUBoulder, Weld46 min
Jun 19, 12:33 PM MDTSevere Thunderstorm WarningBOULarimer42 min
Jun 19, 12:53 PM MDTSevere Thunderstorm WarningBOUArapahoe, Denver, Douglas, Jefferson52 min
Jun 19, 12:56 PM MDTSevere Thunderstorm WarningBOUWeld49 min
Jun 19, 1:14 PM MDTTornado WarningBOUWeld31 min
Jun 19, 1:18 PM MDTSevere Thunderstorm WarningBOULarimer, Weld42 min
Jun 19, 1:29 PM MDTSevere Thunderstorm WarningBOUAdams, Arapahoe46 min
Jun 19, 1:40 PM MDTTornado WarningBOUWeld35 min
Jun 19, 1:43 PM MDTSevere Thunderstorm WarningBOUWeld47 min
Jun 19, 2:02 PM MDTSevere Thunderstorm WarningBOULarimer, Weld43 min
Jun 19, 2:13 PM MDTSevere Thunderstorm WarningBOUAdams, Morgan, Weld47 min
Jun 19, 2:15 PM MDTSevere Thunderstorm WarningBOUArapahoe, Elbert45 min
Jun 19, 2:20 PM MDTTornado Warning Tornado observedBOUAdams, Morgan, Weld25 min
Jun 19, 2:43 PM MDTSevere Thunderstorm WarningBOUWeld47 min
Jun 19, 2:45 PM MDTTornado WarningBOUAdams, Morgan, Weld30 min
Jun 19, 2:57 PM MDTTornado WarningBOUArapahoe, Elbert33 min
Jun 19, 3:22 PM MDTSevere Thunderstorm WarningBOUWashington53 min
Jun 19, 3:26 PM MDTSevere Thunderstorm WarningBOUElbert49 min
Jun 19, 3:29 PM MDTSevere Thunderstorm WarningBOUWeld46 min
Jun 19, 3:30 PM MDTSevere Thunderstorm WarningBOUArapahoe, Douglas, Elbert45 min
Jun 19, 3:39 PM MDTTornado WarningBOUElbert36 min
Jun 19, 3:57 PM MDTSevere Thunderstorm WarningBOUAdams23 min
Jun 19, 4:04 PM MDTSevere Thunderstorm WarningBOUElbert41 min
Jun 19, 4:10 PM MDTSevere Thunderstorm WarningBOUMorgan, Weld50 min
Jun 19, 4:15 PM MDTSevere Thunderstorm WarningBOULarimer30 min
Jun 19, 4:18 PM MDTSevere Thunderstorm WarningBOUWashington57 min
Jun 19, 4:32 PM MDTSevere Thunderstorm WarningBOUElbert, Lincoln58 min
Jun 19, 4:34 PM MDTSevere Thunderstorm WarningBOUWeld41 min
Jun 19, 4:42 PM MDTTornado WarningBOULincoln18 min
Jun 19, 4:51 PM MDTTornado WarningBOUMorgan24 min
Jun 19, 4:57 PM MDTTornado Warning Tornado observedBOULincoln33 min
Jun 19, 5:15 PM MDTSevere Thunderstorm WarningBOUWeld45 min
Jun 19, 5:22 PM MDTTornado WarningBOULincoln13 min
Jun 19, 5:24 PM MDTSevere Thunderstorm WarningBOUElbert51 min

Nearby

Flash Flood Warnings in Colorado, 2018Every flash flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.