Alert archive / Utah / Flood Watches in 2021

Flood Watch 2, NWS Salt Lake City, UT

October 7, 202111 counties in Utah

NWS Salt Lake City, UT issued this flood watch at Oct 7, 2021, 2:45 PM MDT for 11 counties in Utah. It took effect at Oct 8, 2021, 8:00 AM MDT. It was in force for 16 hr.

The area

The counties it named.

The facts

Issued
Oct 7, 2021, 2:45 PM MDT (20:45 UTC)
In effect from
Oct 8, 2021, 8:00 AM MDT
Expired
Oct 9, 2021, 12:00 AM MDT
In force
16 hr
Issued by
NWS Salt Lake City, UT
Flood severity
None

Counties Box Elder County, UT, Cache County, UT, Davis County, UT, Iron County, UT, Kane County, UT, Morgan County, UT, Rich County, UT, Salt Lake County, UT, Summit County, UT, Washington County, UT, Weber County, UT

The radar

The Salt Lake City radar (KMTX), 122 km from the middle of the area, began a volume at 20:44 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.

The nearest sounding before it

Salt Lake City I, UT (KSLC), launched 12:00Z, 8.8 hours before the alert went out and 67 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, Salt Lake City I, UT at 12:00Z on 2021-10-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 40 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Salt Lake City I, UT at 12:00Z on 2021-10-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 48 square meters per square second.193958Sfc1 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
40 J/kg
Mixed-layer CIN
-97 J/kg
Mixed-layer LCL
1145 m above ground
0-6 km bulk shear
31 kt
0-1 km storm-relative helicity
48 m²/s²
0-3 km storm-relative helicity
148 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.6

Open this sounding in Storm Lab

The text

As transmitted.

756 
WGUS65 KSLC 072045
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
245 PM MDT Thu Oct 7 2021

UTZ103-107-110-080445-
/O.NEW.KSLC.FA.A.0002.211008T1800Z-211009T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Box Elder County-Cache Valley/Utah Portion-Wasatch Mountains
I-80 North-
Including the cities of Logan Summit, Logan, Snowville, Mantua, 
Smithfield, and Brigham City
245 PM MDT Thu Oct 7 2021

...FLOOD WATCH IN EFFECT FROM FRIDAY AFTERNOON THROUGH FRIDAY 
EVENING...

The National Weather Service in Salt Lake City has issued a

* Flood Watch for a portion of Utah, including the following areas, 
  Cache Valley/Utah Portion, Eastern Box Elder County and Wasatch 
  Mountains I-80 North.

* From Friday afternoon through Friday evening.

* Heavy rain with embedded thunderstorms are expected to develop 
  over northern Utah Friday afternoon and evening, especially along 
  an axis from around Tremonton and Brigham City to Logan.

* Heavy rain may result in flooding of basements, poor drainage 
  areas, urban areas, and small streams. No main stem river flooding 
  is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

Church
4 follow-up statements
302 
WGUS65 KSLC 081010
FFASLC

URGENT - IMMEDIATE BROADCAST REQUESTED
Flood Watch
National Weather Service Salt Lake City UT
410 AM MDT Fri Oct 8 2021

UTZ124-081900-
/O.EXB.KSLC.FA.A.0002.211008T1400Z-211009T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Zion National Park-
Including the cities of Springdale
410 AM MDT Fri Oct 8 2021

...FLOOD WATCH IN EFFECT FROM 8 AM MDT THIS MORNING THROUGH THIS 
AFTERNOON...

The National Weather Service in Salt Lake City has expanded the

* Flood Watch to include a portion of Utah, including the following 
  area, Zion National Park.

* From 8 AM MDT this morning through this afternoon.

* Widespread rainfall will move over Zion National Park this 
  morning, and continue into early afternoon before tapering to 
  showers. This rainfall will become moderate to heavy at times, 
  with totals approaching 1 inch expected across the watch area.

* Flooding is possible within all slot canyons, small streams, and 
  normally dry washes across the watch area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

UTZ103-107-110-081900-
/O.CON.KSLC.FA.A.0002.211008T1800Z-211009T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Box Elder County-Cache Valley/Utah Portion-Wasatch Mountains
I-80 North-
Including the cities of Logan Summit, Logan, Snowville, Mantua, 
Smithfield, and Brigham City
410 AM MDT Fri Oct 8 2021

...FLOOD WATCH REMAINS IN EFFECT FROM NOON MDT TODAY THROUGH THIS 
EVENING...

The Flood Watch continues for

* A portion of Utah, including the following areas, Cache 
  Valley/Utah Portion, Eastern Box Elder County and Wasatch 
  Mountains I-80 North.

* From Noon MDT today through this evening.

* Heavy rain with embedded thunderstorms are expected to develop 
  over northern Utah Friday afternoon and evening, especially along 
  an axis from around Tremonton and Brigham City to Logan.

* Heavy rain may result in flooding of basements, poor drainage 
  areas, urban areas, and small streams. No main stem river flooding 
  is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

MPS
647 
WGUS65 KSLC 081849
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
1249 PM MDT Fri Oct 8 2021

UTZ103-107-110-090300-
/O.CON.KSLC.FA.A.0002.000000T0000Z-211009T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Box Elder County-Cache Valley/Utah Portion-Wasatch Mountains
I-80 North-
Including the cities of Logan Summit, Logan, Snowville, Mantua, 
Smithfield, and Brigham City
1249 PM MDT Fri Oct 8 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

The Flood Watch continues for

* A portion of Utah, including the following areas, Cache 
  Valley/Utah Portion, Eastern Box Elder County and Wasatch 
  Mountains I-80 North.

* Until Midnight MDT tonight.

* Heavy rain with embedded thunderstorms is expected to continue 
  through late evening, especially along an axis from around 
  Tremonton and Brigham City to Logan.

* Heavy rain may result in flooding of basements, poor drainage 
  areas, urban areas, and small streams. No main stem river flooding 
  is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

UTZ124-090000-
/O.CON.KSLC.FA.A.0002.000000T0000Z-211009T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Zion National Park-
Including the cities of Springdale
1249 PM MDT Fri Oct 8 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL 6 PM MDT THIS EVENING...

The Flood Watch continues for

* A portion of Utah, including the following area, Zion National 
  Park.

* Until 6 PM MDT this evening.

* Widespread rainfall will continue into early afternoon before 
  tapering to showers. This rainfall will continue to be moderate to 
  heavy at times, with totals approaching 1 inch expected across the 
  watch area.

* Flooding is possible within all slot canyons, small streams, and 
  normally dry washes across the watch area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

CRK
001 
WGUS65 KSLC 082359
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
559 PM MDT Fri Oct 8 2021

UTZ124-090100-
/O.EXP.KSLC.FA.A.0002.000000T0000Z-211009T0000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Zion National Park-
Including the cities of Springdale
559 PM MDT Fri Oct 8 2021

...FLOOD WATCH WILL EXPIRE AT 6 PM MDT THIS EVENING...

The Flood Watch will expire at 6 PM MDT this evening for a portion 
of Utah, including the following area, Zion National Park.

The Flood Watch will expire at 6PM MDT. Rain is ending across the 
area. Elevated flows will continue to recede.

$$

UTZ103-107-110-090600-
/O.CON.KSLC.FA.A.0002.000000T0000Z-211009T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Box Elder County-Cache Valley/Utah Portion-Wasatch Mountains
I-80 North-
Including the cities of Logan Summit, Logan, Snowville, Mantua, 
Smithfield, and Brigham City
559 PM MDT Fri Oct 8 2021

...FLOOD WATCH REMAINS IN EFFECT UNTIL MIDNIGHT MDT TONIGHT...

The Flood Watch continues for

* A portion of Utah, including the following areas, Cache 
  Valley/Utah Portion, Eastern Box Elder County and Wasatch 
  Mountains I-80 North.

* Until Midnight MDT tonight.

* Heavy rain with embedded thunderstorms is expected to continue 
  through late evening, especially along an axis from around 
  Tremonton and Brigham City to Logan.

* Heavy rain may result in flooding of basements, poor drainage 
  areas, urban areas, and small streams. No main stem river flooding 
  is expected.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

You should monitor later forecasts and be alert for possible Flood 
Warnings. Those living in areas prone to flooding should be prepared 
to take action should flooding develop.

&&

$$

AD
109 
WGUS65 KSLC 090558
FFASLC

Flood Watch
National Weather Service Salt Lake City UT
1158 PM MDT Fri Oct 8 2021

UTZ103-107-110-090700-
/O.EXP.KSLC.FA.A.0002.000000T0000Z-211009T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Box Elder County-Cache Valley/Utah Portion-Wasatch Mountains
I-80 North-
Including the cities of Logan Summit, Logan, Snowville, Mantua, 
Smithfield, and Brigham City
1158 PM MDT Fri Oct 8 2021

...FLOOD WATCH WILL EXPIRE AT MIDNIGHT MDT TONIGHT...

The Flood Watch will expire at Midnight MDT tonight for a portion of 
Utah, including the following areas, Cache Valley/Utah Portion, 
Eastern Box Elder County and Wasatch Mountains I-80 North.

Showers will continue into the overnight hours across northern Utah, 
however flooding is no longer expected to pose a significant threat.

$$

MPS

The office that day

Everything else NWS Salt Lake City, UT issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 7, 3:09 PM MDTWinter Weather AdvisorySLCDuchesne, Summit, Wasatch51 hr

Nearby

Flood Watches in Utah, 2021Every flood watch in 2021

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.