Alert archive / Iowa / Winter Weather Advisories in 2018

Winter Weather Advisory 21, NWS Sioux Falls, SD

April 18, 2018Lyon County, Sioux County, Iowa

NWS Sioux Falls, SD issued this winter weather advisory at Apr 18, 2018, 2:59 AM CDT for Lyon County, Sioux County, Iowa. It took effect at Apr 18, 2018, 4:00 AM CDT. It was in force for 14 hr.

The area

The counties it named.

The facts

Issued
Apr 18, 2018, 2:59 AM CDT (07:59 UTC)
In effect from
Apr 18, 2018, 4:00 AM CDT
Expired
Apr 18, 2018, 5:44 PM CDT
In force
14 hr
Issued by
NWS Sioux Falls, SD

Counties Lyon County, IA, Sioux County, IA

The radar

The Sioux Falls radar (KFSD), 59 km from the middle of the area, began a volume at 08:02 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

Omaha, NE (KOAX), launched 00:00Z, 8.0 hours before the alert went out and 213 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, Omaha, NE at 00:00Z on 2018-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Omaha, NE at 00:00Z on 2018-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 88 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1999 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
88 m²/s²
0-3 km storm-relative helicity
505 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

421 
WWUS43 KFSD 180759
WSWFSD

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sioux Falls SD
259 AM CDT Wed Apr 18 2018

IAZ001-012-181600-
/O.CAN.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
/O.NEW.KFSD.WW.Y.0021.180418T0900Z-180419T0000Z/
Lyon IA-Sioux-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 
  inches are expected.

* WHERE...Lyon IA and Sioux Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

MNZ071-072-SDZ040-180900-
/O.CAN.KFSD.WW.Y.0020.180418T0900Z-180419T0000Z/
Lincoln MN-Lyon MN-Brookings-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

The storm system is shifting south, and thus less snow is expected
through the Highway 14 corridor. Occasional light snow may still
produce accumulations up to 2 inches.

$$

SDZ038-039-180900-
/O.CAN.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Beadle-Kingsbury-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

The storm system is shifting south, and thus less snow is expected
through the Highway 14 corridor. Occasional light snow may still
produce accumulations up to 2 inches.

$$

IAZ002-003-013-014-181600-
/O.UPG.KFSD.WW.Y.0020.180418T0900Z-180419T0000Z/
/O.NEW.KFSD.WS.W.0007.180418T0900Z-180419T0000Z/
Osceola-Dickinson-O'Brien-Clay IA-
259 AM CDT Wed Apr 18 2018

...WINTER STORM WARNING IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heavy snow expected. Total snow accumulations of 5 to 7
  inches are expected, with locally higher amounts possible.

* WHERE...Osceola, Dickinson, O'Brien and Clay IA Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute. Expect significant 
  reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IAZ021-022-181600-
/O.UPG.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
/O.NEW.KFSD.WS.W.0007.180418T0900Z-180419T0000Z/
Cherokee-Buena Vista-
259 AM CDT Wed Apr 18 2018

...WINTER STORM WARNING IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heavy snow expected, with brief mixed precipitation
  possible. Total snow accumulations of 5 to 7 inches are
  expected, with locally higher snowfall amounts and a glaze of
  ice accumulation possible.

* WHERE...Cherokee and Buena Vista Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute. Expect significant 
  reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning means significant amounts of snow, sleet
and ice will make travel very hazardous or impossible. The latest
road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

IAZ031-NEZ014-SDZ070-071-181600-
/O.EXT.KFSD.WW.Y.0020.000000T0000Z-180418T1800Z/
Woodbury-Dakota-Clay SD-Union-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...Snow expected, possibly mixing with rain before ending.
  Total snow accumulations of 3 to 5 inches are expected, with
  locally higher amounts possible.

* WHERE...In South Dakota, Clay SD and Union Counties. In 
  Nebraska, Dakota County. In Iowa, Woodbury County.

* WHEN...Until 1 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory means that periods of snow, sleet or
freezing rain will cause travel difficulties. Expect slippery
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

SDZ056-181600-
/O.EXT.KFSD.WW.Y.0020.180418T0759Z-180418T2100Z/
Moody-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...

* WHAT...Snow expected, possibly mixing with rain before ending.
  Total snow accumulations of 2 to 5 inches are expected.

* WHERE...Moody County.

* WHEN...Until 4 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

NEZ013-SDZ050-052-057>059-063>065-068-069-181600-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T1800Z/
Dixon-Gregory-Jerauld-Brule-Aurora-Davison-Charles Mix-Douglas-
Hutchinson-Bon Homme-Yankton-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...Snow expected, possibly mixing with rain before ending.
  Total snow accumulations of 2 to 5 inches are expected, with
  locally higher amounts possible.

* WHERE...Portions of central, south central and southeast South 
  Dakota and northeast Nebraska.

* WHEN...Until 1 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory means that periods of snow, sleet or
freezing rain will cause travel difficulties. Expect slippery
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

IAZ020-032-SDZ053>055-060>062-066-067-181600-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Plymouth-Ida-Sanborn-Miner-Lake-Hanson-McCook-Minnehaha-Turner-
Lincoln SD-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...

* WHAT...Snow expected, possibly mixing with rain before ending.
  Total snow accumulations of 2 to 5 inches are expected, with
  locally higher amounts possible south of Highway 18.

* WHERE...Portions of east central and southeast South Dakota 
  and northwest and west central Iowa.

* WHEN...Until 4 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory means that periods of snow, sleet or
freezing rain will cause travel difficulties. Expect slippery
roads and limited visibilities, and use caution while driving.
The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

MNZ080-081-089-090-097-098-181600-
/O.CON.KFSD.WW.Y.0020.180418T0900Z-180419T0000Z/
Murray-Cottonwood-Nobles-Jackson-Pipestone-Rock-
259 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Snow expected. Total snow accumulations of 2 to 5 inches
  are expected, with locally higher amounts possible toward the
  Interstate 90 corridor.

* WHERE...Portions of southwest Minnesota.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$
3 follow-up statements
297 
WWUS43 KFSD 181640
WSWFSD

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sioux Falls SD
1140 AM CDT Wed Apr 18 2018

MNZ089-090-190000-
/O.UPG.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
/O.EXA.KFSD.WS.W.0007.000000T0000Z-180419T0000Z/
Nobles-Jackson-
1140 AM CDT Wed Apr 18 2018

...WINTER STORM WARNING IN EFFECT UNTIL 7 PM CDT THIS EVENING...

* WHAT...Heavy snow. Total snow accumulations of 6 to 9 inches 
  are expected.

* WHERE...Nobles and Jackson Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect  
  significant reductions in visibility at times. Accumulating snow
  will continue into the early evening hours. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IAZ002-003-013-014-021-022-190000-
/O.CON.KFSD.WS.W.0007.000000T0000Z-180419T0000Z/
Osceola-Dickinson-O'Brien-Clay IA-Cherokee-Buena Vista-
1140 AM CDT Wed Apr 18 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Heavy snow. Total snow accumulations of 6 to 9 inches 
  are expected.

* WHERE...Portions of northwest Iowa.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  significant reductions in visibility at times. Accumulating snow
  will continue through the afternoon and possibly into the early
  evening. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

SDZ050-052-057>059-063>065-068>071-181800-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T1800Z/
Gregory-Jerauld-Brule-Aurora-Davison-Charles Mix-Douglas-
Hutchinson-Bon Homme-Yankton-Clay SD-Union-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...Snow. Total snow accumulations of 5 to 8 inches are
  expected. Locally heavier amounts are possible especially in
  higher terrained area.

* WHERE...Portions of central, south central and southeast South 
  Dakota.

* WHEN...Until 1 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities. Accumulating snow will rapidly diminish
  through the afternoon hours.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

SDZ060>062-066-067-182100-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Hanson-McCook-Minnehaha-Turner-Lincoln SD-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...

* WHAT...Snow. Total snow accumulations of 5 to 8 inches are
  expected. Locally higher amounts may be possible especially in
  the higher terrained areas.

* WHERE...Hanson, McCook, Minnehaha, Turner and Lincoln SD 
  Counties.

* WHEN...Until 4 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities. Accumulating snow will rapidly diminish
  toward mid afternoon. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

IAZ001-012-190000-
/O.CON.KFSD.WW.Y.0021.000000T0000Z-180419T0000Z/
Lyon IA-Sioux-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Snow. Total snow accumulations of 5 to 8 inches are
  expected. Locally higher amounts are possible especially in the
  higher terrained areas. 

* WHERE...Lyon IA and Sioux Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

MNZ098-190000-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
Rock-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Snow. Total snow accumulations of 5 to 8 inches are 
  expected.

* WHERE...Rock County.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

MNZ080-081-097-190000-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
Murray-Cottonwood-Pipestone-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Snow. Total snow accumulations of 2 to 5 inches are
  expected with the higher amounts approaching Interstate 90.

* WHERE...Murray, Cottonwood and Pipestone Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slick road conditions. Expect
  reduced visibilities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

SDZ053>056-182100-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Sanborn-Miner-Lake-Moody-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...

* WHAT...Snow. Total snow accumulations of 2 to 5 inches are
  expected with the higher amounts approaching Interstate 90.

* WHERE...Sanborn, Miner, Lake and Moody Counties.

* WHEN...Until 4 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slick road conditions. Expect
  reduced visibilities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

IAZ020-032-182100-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Plymouth-Ida-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 4 PM CDT THIS
AFTERNOON...

* WHAT...Snow. Total snow accumulations of 3 to 6 inches are
  expected. Locally heavier amounts are possible in northern
  Plymouth county.

* WHERE...Plymouth and Ida Counties.

* WHEN...Until 4 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

IAZ031-NEZ013-014-181800-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180418T1800Z/
Woodbury-Dixon-Dakota-
1140 AM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 PM CDT THIS
AFTERNOON...

* WHAT...Snow. Total snow accumulations of 2 to 4 inches are 
  expected.

* WHERE...In Nebraska, Dixon and Dakota Counties. In Iowa, 
  Woodbury County.

* WHEN...Until 1 PM CDT this afternoon.

* ADDITIONAL DETAILS...Plan on slippery road conditions. Expect 
  reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$
475 
WWUS43 KFSD 182007
WSWFSD

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sioux Falls SD
307 PM CDT Wed Apr 18 2018

IAZ020-032-SDZ053>056-060>062-066-067-182115-
/O.CAN.KFSD.WW.Y.0020.000000T0000Z-180418T2100Z/
Plymouth-Ida-Sanborn-Miner-Lake-Moody-Hanson-McCook-Minnehaha-
Turner-Lincoln SD-
307 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Some flurries or sprinkles may linger late this afternoon, but
accumulating snow is over. Be alert for slippery road conditions
on the afternoon commute from work or school. 

$$

IAZ002-003-013-014-021-022-190000-
/O.CON.KFSD.WS.W.0007.000000T0000Z-180419T0000Z/
Osceola-Dickinson-O'Brien-Clay IA-Cherokee-Buena Vista-
307 PM CDT Wed Apr 18 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Diminishing snow. Additional snow accumulations of inch
  or less. 

* WHERE...Portions of northwest Iowa.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions,
  including during the evening commute. Expect reductions in
  visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

MNZ089-090-190000-
/O.CON.KFSD.WS.W.0007.000000T0000Z-180419T0000Z/
Nobles-Jackson-
307 PM CDT Wed Apr 18 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Diminishing snow. Additional snow accumulations of an
  inch or less. 

* WHERE...Nobles and Jackson Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions,
  including during the evening commute. Expect reductions in
  visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

IAZ001-012-190000-
/O.CON.KFSD.WW.Y.0021.000000T0000Z-180419T0000Z/
Lyon IA-Sioux-
307 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Diminishing snow. Additional snow accumulations of less
  than an inch. 

* WHERE...Lyon IA and Sioux Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the evening commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

MNZ098-190000-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
Rock-
307 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Diminishing snow. Additional snow accumulations of less
  than an inch. 

* WHERE...Rock County.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the evening commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

MNZ080-081-097-190000-
/O.CON.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
Murray-Cottonwood-Pipestone-
307 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 7 PM CDT THIS
EVENING...

* WHAT...Diminishing snow. Additional snow accumulations of less
  than an inch. 

* WHERE...Murray, Cottonwood and Pipestone Counties.

* WHEN...Until 7 PM CDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the evening commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$
061 
WWUS43 KFSD 182244
WSWFSD

URGENT - WINTER WEATHER MESSAGE
National Weather Service Sioux Falls SD
544 PM CDT Wed Apr 18 2018



IAZ002-003-013-014-021-022-MNZ089-090-182345-
/O.CAN.KFSD.WS.W.0007.000000T0000Z-180419T0000Z/
Osceola-Dickinson-O'Brien-Clay IA-Cherokee-Buena Vista-Nobles-
Jackson-
544 PM CDT Wed Apr 18 2018

...WINTER STORM WARNING IS CANCELLED...

Light snow or flurries will continue through the early evening,
however little to no additional accumulation is expected. 
Therefore the winter storm warning is cancelled.

$$

IAZ001-012-182345-
/O.CAN.KFSD.WW.Y.0021.000000T0000Z-180419T0000Z/
Lyon IA-Sioux-
544 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Light snow or flurries will continue through the early evening,
however little to no additional accumulation is expected. 
Therefore the winter weather advisory is cancelled.

$$

MNZ080-081-097-098-182345-
/O.CAN.KFSD.WW.Y.0020.000000T0000Z-180419T0000Z/
Murray-Cottonwood-Pipestone-Rock-
544 PM CDT Wed Apr 18 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Light snow or flurries will continue through the early evening,
however little to no additional accumulation is expected. 
Therefore the winter weather advisory is cancelled.

$$

What forecasters said that day

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

NWS Sioux Falls, SD wrote its last area forecast discussion before this winter weather advisory went out at Apr 17, 9:34 PM CDT, 5 hours 25 minutes earlier.

Area forecast discussion, Apr 17, 9:34 PM CDT, 5 hours 25 minutes before
Area Forecast Discussion
National Weather Service Sioux Falls SD
934 PM CDT Tue Apr 17 2018

.UPDATE...
Issued at 918 PM CDT Tue Apr 17 2018

HRRR. RAP, NAMnest, and 00z NAM continue to trend further south
with the approaching shortwave trough. This is supported by the
present location of the trough seen on water vapor. Strong jet
streak and PV anomaly is digging across southwest Nebraska near
the Kansas border, on an eastward track this evening. With the
stronger forcing likewise tracking further south, remaining near
or south of the mid- Missouri valley, have adjusted precipitation
amounts lower in the highway 14 corridor of east central, while
the lower Brule area of south central SD have trended slightly
higher. While this has not altered expected snowfall amounts
significantly, it does bring Gregory county into the 2 to 4 inch
range, so have added them to the advisory. Beadle, Kingsbury,
Sanborn and Jerauld may struggle to reach 2 inches, but given that
they are already in the advisory, did not want to remove them at
this point.

&&

.SHORT TERM...(This evening through Wednesday night)
Issued at 349 PM CDT Tue Apr 17 2018

Current surface analysis shows weak high pressure situated over
Minnesota. Aloft, an upper trough is moving rapidly eastward into
western plains. Another round of snowfall is taking aim across the
area. The upper trough will move into central Nebraska overnight,
before closing off and heading into Iowa on Wednesday. Strong jet
streak of over 100 knots is noted tonight rounding the base of the
upper low near the Nebraska/Kansas border, with a subtle streak
extending northward up the MO River valley of NE/IA. Lift becomes
quite strong with low level moisture increasing rapidly from west to
east tonight. That said, it will take a while for southwest MN to
saturate up so slowed down measurable pops in that area. Between 06Z
and 12Z, very high pops continue to be warranted as they progress
eastward with the deep layer saturation. There is dendricity in the
3-5km layer, and lift is quite strong in this layer between -10 and
-20C. Isentropic lift is strong in the 285-295K layer. Furthermore,
some instability exists in the mid layers late tonight and very
early Wednesday in the Sioux City and Storm Lake areas evidenced by
elevated cape values.

For the details, the models are fairly close with the timing of the
dynamics, moisture, and overall QPF values. The mid level QG forcing
moves squarely over the CWA. There may be a little wintry mix for
locations in extreme northeast NE, extending eastward to Sioux City
and Storm Lake initially overnight tonight before the mid layers
saturate up. But overall the models are under doing the ice
probability function and not introducing snow fast enough as the
profile becomes so deeply saturated. Worried about a bit of a
convective snow burst especially around Storm Lake. Will have to
watch this location for any sort of headline upgrades, because if
they do go convective late tonight or early Wednesday, snow rates
could be an inch an hour for a few hours. This will push Storm
Lake's snow amount over 6 inches. Conversely due to the track of the
system and the main frontal forcing over our southern zones, our
northern and western zones may receive less snowfall then originally
forecast at about 2 inches, perhaps a bit more. Overall elsewhere, 3
to 5 inches of snow looks like a pretty good bet blending the QPF
off of the various cams, and lowering the snow ratio from what
superblend was giving us. Unlike last weekend, fortunately this will
not be an overly wind driven event. But did increase wind speeds
generally from about I 29 and eastward due to the amount of wind at
925mb and gradient expected. So therefore preferred winds in the
breezy category. Most of the visibility reduction in this event will
be due to falling snow and not blowing snow.

Snow streaks are possible Wednesday afternoon west of I 29 due to
cold air aloft and a cyclonic flow. Further east, high pops will
diminish in the evening east of I 29 as the system moves out of the
area. Concerning temperatures, needless to say they will continue to
be immensely below normal for the daytime high on Wednesday, with
readings only in the 30s to around 40 degrees.

.LONG TERM...(Thursday through Tuesday)
Issued at 349 PM CDT Tue Apr 17 2018

On Thursday and Friday, another upper level low will move into the
southwest United States, with our area dominated by an upper ridge
of high pressure. Sprawling surface high pressure will nudge ever so
slowly eastward, setting up shop over the MS valley and Great Lakes
area on Friday and Saturday. This is important as this high will
usher in a low level fetch of dry air from the east, limiting our
pops as the upper low moves closer on Friday and Friday night. Then
on the weekend, the closed upper low tracks too far south to impact
our weather this weekend. Further out on Monday night and Tuesday,
small pops are warranted with a frontal passage coming down from the
north.

In terms of temperatures, Thursday and Friday will continue to be
well above normal, followed by temperatures closer to normal this
weekend. Warmed up highs on Sunday west of I 29 given the 925-900mb
temperature structure over superblend values. Early next week,
temperatures will be a bit cooler on Tuesday when compared to
Monday as the next frontal passage dips southward.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 636 PM CDT Tue Apr 17 2018

Ceilings will begin lowering late this evening, with light rain
or a wintry mix arriving in south central and Missouri Valley
around midnight. The rain or wintry mix will quickly change to
entirely snow in the early morning hours as it spreads eastward.
Expect widespread MVFR and IFR conditions, with brief LIFR in the
heavier snow bands. Winds will not be extreme, but should average
around 10 to 25 KT during snowfall. Visibility will begin
improving after 15z, but low stratus persists through the TAF
period.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory from 1 AM to 4 PM CDT Wednesday for
     SDZ038-039-053>055-060>062-066-067-070-071.

     Winter Weather Advisory from 1 AM to 1 PM CDT Wednesday for
     SDZ050-052-057>059-063>065-068-069.

     Winter Weather Advisory from 4 AM to 7 PM CDT Wednesday for
     SDZ040-056.

MN...Winter Weather Advisory from 4 AM to 7 PM CDT Wednesday for
     MNZ071-072-080-081-089-090-097-098.

IA...Winter Weather Advisory from 1 AM to 4 PM CDT Wednesday for
     IAZ001-012-020>022-031-032.

     Winter Weather Advisory from 4 AM to 7 PM CDT Wednesday for
     IAZ002-003-013-014.

NE...Winter Weather Advisory from 1 AM to 4 PM CDT Wednesday for
     NEZ014.

     Winter Weather Advisory from 1 AM to 1 PM CDT Wednesday for
     NEZ013.

&&

UPDATE...
SHORT TERM...MJ
LONG TERM...MJ
AVIATION...
Hazardous weather outlook, Apr 17, 4:21 AM CDT, 22 hours 38 minutes before
Hazardous Weather Outlook
National Weather Service Sioux Falls SD
421 AM CDT Tue Apr 17 2018

IAZ001-012-020-021-031-032-MNZ071-072-097-098-NEZ013-014-
SDZ038>040-052>056-058>062-065>067-069>071-180930-
Lyon IA-Sioux-Plymouth-Cherokee-Woodbury-Ida-Lincoln MN-Lyon MN-
Pipestone-Rock-Dixon-Dakota-Beadle-Kingsbury-Brookings-Jerauld-
Sanborn-Miner-Lake-Moody-Aurora-Davison-Hanson-McCook-Minnehaha-
Hutchinson-Turner-Lincoln SD-Yankton-Clay SD-Union-
421 AM CDT Tue Apr 17 2018

This Hazardous Weather Outlook is for portions of northwest Iowa,
west central Iowa, southwest Minnesota, northeast Nebraska,
central South Dakota, east central South Dakota, south central
South Dakota, and southeast South Dakota.

.DAY ONE...Today and Tonight

Fog will be possible through mid morning, areas of locally dense
fog may be possible near the Buffalo Ridge areas of eastern South
Dakota and Southwest Minnesota.

A light wintry mix of snow, sleet or freezing rain will arrive
after midnight tonight, with a quick transition to snow expected
before the pre-dawn hours.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Moderate snow will move through the outlook area during the
morning commute, ending during the early afternoon hours. Total
accumulations of 2 to 5 inches of snow will be possible, with very
minimal accumulations of sleet and ice.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

IAZ002-003-013-014-022-MNZ080-081-089-090-180930-
Osceola-Dickinson-O'Brien-Clay IA-Buena Vista-Murray-Cottonwood-
Nobles-Jackson-
421 AM CDT Tue Apr 17 2018

This Hazardous Weather Outlook is for portions of northwest Iowa
and southwest Minnesota.

.DAY ONE...Today and Tonight

Fog will be possible through mid morning, areas of locally dense
fog may be possible near the Buffalo Ridge areas of eastern South
Dakota and Southwest Minnesota.

A light wintry mix of snow, sleet or freezing rain will arrive
after 3am tonight, with a quick transition to snow expected.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Moderate snow will move through the outlook area during the
morning commute, ending during the afternoon hours. Total
accumulations of 3 to 6 inches of snow an isolated 7 inch reports
will be possible. Sleet and freezing rain accumulations will be
minimal.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

SDZ050-057-063-064-068-180930-
Gregory-Brule-Charles Mix-Douglas-Bon Homme-
421 AM CDT Tue Apr 17 2018

This Hazardous Weather Outlook is for portions of south central
South Dakota and southeast South Dakota.

.DAY ONE...Today and Tonight

A light wintry mix of snow, sleet or freezing rain will arrive by
midnight tonight, with a quick transition to snow expected.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Moderate snow will move through the outlook area during the
morning commute, ending by mid morning. Total accumulations of 1
to 3 inches of snow will be possible. Sleet and freezing rain
accumulations will be minimal.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will not be needed.

The office that day

Everything else NWS Sioux Falls, SD issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 18, 2:59 AM CDTWinter Storm WarningFSDBuena Vista, Cherokee, Clay, Dickinson, O'Brien, Osceola15 hr
Apr 18, 10:02 AM CDTRiver Flood WarningFSDLyon7 days
Apr 18, 10:02 AM CDTRiver Flood WarningFSDClay7 days
Apr 18, 10:02 AM CDTRiver Flood WarningFSDCherokee3 days

Nearby

Winter Weather Advisories in Iowa, 2018Every winter weather advisory 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.