Alert archive / Iowa / Heat Advisories in 2017

Heat Advisory 3, NWS Sioux Falls, SD

July 18, 2017Ida County, Woodbury County, Iowa; Dakota County, Dixon County, Nebraska

NWS Sioux Falls, SD issued this heat advisory at Jul 18, 2017, 3:07 PM CDT for Ida County, Woodbury County, Iowa; Dakota County, Dixon County, Nebraska. It took effect at Jul 20, 2017, 1:00 PM CDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Jul 18, 2017, 3:07 PM CDT (20:07 UTC)
In effect from
Jul 20, 2017, 1:00 PM CDT
Expired
Jul 20, 2017, 8:00 PM CDT
In force
7 hr
Issued by
NWS Sioux Falls, SD

Counties Ida County, IA, Woodbury County, IA, Dakota County, NE, Dixon County, NE

The radar

The Omaha radar (KOAX), 122 km from the middle of the area, began a volume at 20:07 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 12:00Z, 8.1 hours before the alert went out and 122 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 12:00Z on 2017-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 367 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, Omaha, NE at 12:00Z on 2017-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 33 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
367 J/kg
Mixed-layer CIN
-70 J/kg
Mixed-layer LCL
1063 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
33 m²/s²
0-3 km storm-relative helicity
-25 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

683 
WWUS73 KFSD 182007
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
307 PM CDT Tue Jul 18 2017


IAZ031-032-NEZ013-014-190415-
/O.NEW.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
/O.NEW.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
307 PM CDT Tue Jul 18 2017

...HEAT ADVISORY IN EFFECT FROM 1 PM TO 8 PM CDT WEDNESDAY...
...HEAT ADVISORY IN EFFECT FROM 1 PM TO 8 PM CDT THURSDAY...

The National Weather Service in Sioux Falls has issued a Heat
Advisory, which is in effect from 1 PM to 8 PM CDT Wednesday. A
Heat Advisory has also been issued from 1 PM to 8 PM CDT
Thursday. 

* TEMPERATURE...High temperatures will reach the mid 90s Wednesday
  and Thursday afternoon producing heat index values between 100
  and 105 degrees.

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

   Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

   To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$

IAZ001-012-020-021-SDZ050-052-053-057>071-190415-
/O.NEW.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
Lyon IA-Sioux-Plymouth-Cherokee-Gregory-Jerauld-Sanborn-Brule-
Aurora-Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
307 PM CDT Tue Jul 18 2017

...HEAT ADVISORY IN EFFECT FROM 1 PM TO 8 PM CDT WEDNESDAY...

The National Weather Service in Sioux Falls has issued a Heat
Advisory, which is in effect from 1 PM to 8 PM CDT Wednesday. 

* TEMPERATURE...High temperatures will reach the mid 90s Wednesday 
  afternoon producing heat index values between 100 and 105 
  degrees.

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

   Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

   To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$
6 follow-up statements
788 
WWUS73 KFSD 190352
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
1052 PM CDT Tue Jul 18 2017


IAZ031-032-NEZ013-014-191200-
/O.CON.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
/O.CON.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
1052 PM CDT Tue Jul 18 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
WEDNESDAY...
...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
THURSDAY...

* TEMPERATURE...High temperatures will reach the mid 90s 
  Wednesday and Thursday afternoon producing heat index values 
  between 100 and 105 degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

  Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

  To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$

IAZ001-012-020-021-SDZ050-052-053-057>071-191200-
/O.CON.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
Lyon IA-Sioux-Plymouth-Cherokee-Gregory-Jerauld-Sanborn-Brule-
Aurora-Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
1052 PM CDT Tue Jul 18 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
WEDNESDAY...

* TEMPERATURE...High temperatures will reach the mid 90s 
  Wednesday afternoon producing heat index values between 100 
  and 105 degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

  Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

  To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$
831 
WWUS73 KFSD 190844
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
344 AM CDT Wed Jul 19 2017

IAZ013-022-SDZ038-054-191645-
/O.EXA.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
O'Brien-Buena Vista-Beadle-Miner-
344 AM CDT Wed Jul 19 2017

...HEAT ADVISORY IN EFFECT FROM 1 PM THIS AFTERNOON TO 8 PM CDT
THIS EVENING...

The National Weather Service in Sioux Falls has issued a Heat
Advisory, which is in effect from 1 PM this afternoon to 8 PM CDT
this evening. 

* TEMPERATURE...High temperatures will reach the mid 90s this 
  afternoon producing heat index values between 100 and 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

Take extra precautions...if you work or spend time outside. When 
possible...reschedule strenuous activities to early morning or 
evening. Know the signs and symptoms of heat exhaustion and heat 
stroke. Wear light weight and loose fitting clothing when possible
and drink plenty of water.

To reduce risk during outdoor work...the occupational safety and 
health administration recommends scheduling frequent rest breaks 
in shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an 
emergency...call 9 1 1.

&&

$$

IAZ031-032-NEZ013-014-191645-
/O.CON.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
/O.CON.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
344 AM CDT Wed Jul 19 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
8 PM CDT THIS EVENING...
...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
THURSDAY...

* TEMPERATURE...High temperatures will reach the mid 90s Wednesday
  and Thursday afternoon producing heat index values around 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

Take extra precautions...if you work or spend time outside. When 
possible...reschedule strenuous activities to early morning or 
evening. Know the signs and symptoms of heat exhaustion and heat 
stroke. Wear light weight and loose fitting clothing when possible
and drink plenty of water.

To reduce risk during outdoor work...the occupational safety and 
health administration recommends scheduling frequent rest breaks 
in shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an 
emergency...call 9 1 1.

&&

$$

IAZ001-012-020-021-SDZ050-052-053-057>071-191645-
/O.CON.KFSD.HT.Y.0002.170719T1800Z-170720T0100Z/
Lyon IA-Sioux-Plymouth-Cherokee-Gregory-Jerauld-Sanborn-Brule-
Aurora-Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
344 AM CDT Wed Jul 19 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
8 PM CDT THIS EVENING...

* TEMPERATURE...High temperatures will reach the mid 90s 
  Wednesday afternoon producing heat index values between 100 
  and 105 degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

Take extra precautions...if you work or spend time outside. When 
possible...reschedule strenuous activities to early morning or 
evening. Know the signs and symptoms of heat exhaustion and heat 
stroke. Wear light weight and loose fitting clothing when possible
and drink plenty of water.

To reduce risk during outdoor work...the occupational safety and 
health administration recommends scheduling frequent rest breaks 
in shaded or air conditioned environments. Anyone overcome by heat
should be moved to a cool and shaded location. Heat stroke is an 
emergency...call 9 1 1.

&&

$$
998 
WWUS73 KFSD 192017
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
317 PM CDT Wed Jul 19 2017


SDZ038-053-054-061-062-192130-
/O.CAN.KFSD.HT.Y.0002.000000T0000Z-170720T0100Z/
Beadle-Sanborn-Miner-McCook-Minnehaha-
317 PM CDT Wed Jul 19 2017

...HEAT ADVISORY IS CANCELLED...

The National Weather Service in Sioux Falls has cancelled the
Heat Advisory. 

The heat index will be below 100 this afternoon.

$$

IAZ031-032-NEZ013-014-200430-
/O.CON.KFSD.HT.Y.0002.000000T0000Z-170720T0100Z/
/O.CON.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
317 PM CDT Wed Jul 19 2017

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...
...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
THURSDAY...

* TEMPERATURE...High temperatures will reach the mid 90s this
  afternoon and Thursday afternoon producing heat index values
  between 100 and 105 degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

Take extra precautions...if you work or spend time outside. When
possible...reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

To reduce risk during outdoor work...the occupational safety and
health administration recommends scheduling frequent rest breaks
in shaded or air conditioned environments. Anyone overcome by
heat should be moved to a cool and shaded location. Heat stroke
is an emergency...call 9 1 1.

&&

$$

IAZ001-012-013-020>022-SDZ050-052-057>060-063>071-200100-
/O.CON.KFSD.HT.Y.0002.000000T0000Z-170720T0100Z/
Lyon IA-Sioux-O'Brien-Plymouth-Cherokee-Buena Vista-Gregory-
Jerauld-Brule-Aurora-Davison-Hanson-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
317 PM CDT Wed Jul 19 2017

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...

* TEMPERATURE...High temperatures will reach the mid 90s this
  afternoon producing heat index values between 100 and 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

Take extra precautions...if you work or spend time outside. When
possible...reschedule strenuous activities to early morning or
evening. Know the signs and symptoms of heat exhaustion and heat
stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

To reduce risk during outdoor work...the occupational safety and
health administration recommends scheduling frequent rest breaks
in shaded or air conditioned environments. Anyone overcome by
heat should be moved to a cool and shaded location. Heat stroke
is an emergency...call 9 1 1.

&&

$$
888 
WWUS73 KFSD 200108
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
808 PM CDT Wed Jul 19 2017


IAZ031-032-NEZ013-014-201145-
/O.EXP.KFSD.HT.Y.0002.000000T0000Z-170720T0100Z/
/O.CON.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
808 PM CDT Wed Jul 19 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM TO 8 PM CDT
THURSDAY...
...HEAT ADVISORY HAS EXPIRED...

* TEMPERATURE...High temperatures will reach the mid 90s Thursday
  afternoon producing heat index values between 100 and 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

   Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

   To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$

IAZ001-012-013-020>022-SDZ050-052-057>060-063>071-200215-
/O.EXP.KFSD.HT.Y.0002.000000T0000Z-170720T0100Z/
Lyon IA-Sioux-O'Brien-Plymouth-Cherokee-Buena Vista-Gregory-
Jerauld-Brule-Aurora-Davison-Hanson-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
808 PM CDT Wed Jul 19 2017

...HEAT ADVISORY HAS EXPIRED...

Heat index values will again approach 100 degrees Thursday
afternoon.

$$
179 
WWUS73 KFSD 200805
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
305 AM CDT Thu Jul 20 2017

IAZ031-032-NEZ013-014-201615-
/O.CON.KFSD.HT.Y.0003.170720T1800Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
305 AM CDT Thu Jul 20 2017

...HEAT ADVISORY REMAINS IN EFFECT FROM 1 PM THIS AFTERNOON TO
8 PM CDT THIS EVENING...

* TEMPERATURE...High temperatures will reach the mid 90s this 
  afternoon producing heat index values between 100 and 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

  Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

  To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$
452 
WWUS73 KFSD 202025
NPWFSD

URGENT - WEATHER MESSAGE
National Weather Service Sioux Falls SD
325 PM CDT Thu Jul 20 2017


IAZ031-032-NEZ013-014-210430-
/O.NEW.KFSD.HT.Y.0004.170721T1700Z-170722T0100Z/
/O.CON.KFSD.HT.Y.0003.000000T0000Z-170721T0100Z/
Woodbury-Ida-Dixon-Dakota-
325 PM CDT Thu Jul 20 2017

...HEAT ADVISORY REMAINS IN EFFECT UNTIL 8 PM CDT THIS EVENING...
...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM CDT FRIDAY...

The National Weather Service in Sioux Falls has issued a Heat
Advisory, which is in effect from noon to 8 PM CDT Friday. 

* TEMPERATURE...High temperatures will reach the mid 90s this 
  afternoon producing heat index values between 100 and 105 
  degrees. 

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

 Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

 To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$

IAZ001-002-012-013-020>022-MNZ098-SDZ038-039-050-052>071-210430-
/O.NEW.KFSD.HT.Y.0004.170721T1700Z-170722T0100Z/
Lyon IA-Osceola-Sioux-O'Brien-Plymouth-Cherokee-Buena Vista-Rock-
Beadle-Kingsbury-Gregory-Jerauld-Sanborn-Miner-Lake-Moody-Brule-
Aurora-Davison-Hanson-McCook-Minnehaha-Charles Mix-Douglas-
Hutchinson-Turner-Lincoln SD-Bon Homme-Yankton-Clay SD-Union-
325 PM CDT Thu Jul 20 2017

...HEAT ADVISORY IN EFFECT FROM NOON TO 8 PM CDT FRIDAY...

The National Weather Service in Sioux Falls has issued a Heat
Advisory, which is in effect from noon to 8 PM CDT Friday. 

* TEMPERATURE...High temperatures will reach the mid to upper 90s
  Friday afternoon and evening, producing heat index values from
  100 to near 110 degrees.
  

* IMPACTS...The combination of hot temperatures and high 
  humidity will increase the potential for heat-related stress 
  and illness. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Heat Advisory means that a period of hot temperatures is
expected. The combination of hot temperatures and high humidity
will combine to create a situation in which heat illnesses are
possible. Drink plenty of fluids...stay in an air-conditioned
room...stay out of the sun...and check up on relatives and
neighbors.

   Take extra precautions...if you work or spend time outside.
When possible...reschedule strenuous activities to early morning
or evening. Know the signs and symptoms of heat exhaustion and
heat stroke. Wear light weight and loose fitting clothing when
possible and drink plenty of water.

   To reduce risk during outdoor work...the occupational safety
and health administration recommends scheduling frequent rest
breaks in shaded or air conditioned environments. Anyone overcome
by heat should be moved to a cool and shaded location.   Heat
stroke is an emergency...call 9 1 1.

&&

$$

What forecasters said that day

The local office's own words before this heat 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 heat advisory went out at Jul 18, 2:57 PM CDT, 10 minutes earlier.

Area forecast discussion, Jul 18, 2:57 PM CDT, 10 minutes before
Area Forecast Discussion
National Weather Service Sioux Falls SD
257 PM CDT Tue Jul 18 2017

.SHORT TERM...(This evening through Wednesday)
Issued at 257 PM CDT Tue Jul 18 2017

Upper air analysis shows a ridge of high pressure centered over the
central and southern through Wednesday, with a weak surface cold
front extending from east to west just south of Interstate 90. The
forecast area will remain on the southern edge of some pretty strong
westerlies which reside to our north, and the surface front will
make progress only to about Sioux City to Storm Lake before
stalling. Spotty convection has broken out near the surface boundary
across the heart of northwest Iowa. There is not a lot of upper
forcing either right now or tonight to work with. PV along the 1.5
pressure surface is virtually non existent, so current thoughts are
that convection will remain tied to the surface to 850mb wind shift
line this evening. It is unstable, but with weak wind shear in the
lowest couple of kilometers, do not think that severe potential will
become widespread late this afternoon or evening due to a lack of
upper forcing. Still, its certainly worth watching for the next
several hours. Introduced some chances for TSRA late tonight between
06Z and 12Z Wednesday near the I 90 corridor as the low level jet
shifts back to a southeasterly direction. The I 90 corridor is
forecast to be along a wind shift late tonight from a southerly, to
easterly direction, and fairly strong thetae advection maximized
along 925mb is noted as it shifts off to the northwest late tonight.
Did not want to go very high with the rain chances late tonight
however due to rising heights and mid level warm air advection.

The rising heights and mid level warm air advection continue into
Wednesday. In fact by afternoon, both the nam and gfs have a bulk of
of our forecast area at +14 to +15C at 700mb. With our frontal
boundary currently where it is right now shifting back northward
tonight, Wednesday looks to be hot and humid, with a heat advisory
warranted for southeast and south central SD, as well as parts of
northwest IA and extreme northeast Nebraska for heat index values of
100 to 105 degrees. Due to the very warm mid level temperatures,
convective chances during the Wednesday day period are extremely
small, although a few morning thunderstorms could be lingering in
our northwest zones with the aforementioned thetae boundary lifting
northward. Although highs will be in the 90s on Wednesday,
convective temperatures are 100 to 105 degrees, so convective
initiation in the afternoon is pretty remote.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 257 PM CDT Tue Jul 18 2017

Unsettled pattern continues through the end of the week as a series
of disturbances continue to slowly break down the ridge.
Disturbances will kick off a series of chances for showers and
strong to severe thunderstorms while temperatures will slowly become
more seasonable as the ridge breaks down.

Wave swings through Wednesday night bringing chances of rain to the
Highway 14 corridor and southwest Minnesota. Instability will be
plenty sufficient for thunderstorms with CAPE values over 3,000 J/kg
expected. Deep layer shear is strong, with over 50 knots 0-6km
shear, so expect convection to be well organized. However,
convective inhibition remains a concern across our CWA with a fairly
strong cap from 700-800mb seen on model soundings at BKX and MML.
Models have trended accordingly and are now keeping most of the
convection just north and northeast of our CWA. Nevertheless, will
need to keep on eye on this impacting our northern and northeastern
border, especially for severe wind gusts with DCAPE around 1,000
J/kg.

Expected lack of lingering convective debris from Wednesday night
will lead to a hot and muggy day in our southern zones. Heat indices
are likely to exceed 100 around Sioux City. Will go ahead and issue
a heat advisory for Thursday afternoon. As for precipitation, it
will be deja vu all over again Thursday night, this time with only
our edge in southwest Minnesota possibly being affected. Instability
is sufficient but 700-800mb capping may once again keep the
convection out of the CWA save for parts of Lyon and Cottonwood
counties.

Pattern calms considerably by Friday evening. GFS suggests a round
of storms along and south of I-90 Saturday evening but will discount
that for now as it is a significant outlier. But, the upper jet does
linger just to our north through the weekend, so can't totally rule
out showers and storms. However, QG support for broad lift and
moisture are lacking so will keep chances low for now.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1213 PM CDT Tue Jul 18 2017

Main issue today and tonight is a weak cold frontal passage and
associated TSRA chances. Currently at 17Z Tuesday, the frontal
passage is close to Interstate 90, but it is difficult to
ascertain whether this is the primary frontal wind shift, or
residual outflow from thunderstorms in northern SD this morning.
At any rate, the surface winds should generally veer to an
easterly direction as the day progresses into tonight, with Sioux
City's wind direction possibly the most variable, albeit fairly
light in speed. Convective chances associated with the frontal
boundary are quite a challenge. Right now, timed the TSRA as best
as possible in the KFSD and KSUX TAF sites with not enough
confidence to go a TEMPO group at this time. One final item to
watch for, is if rainfall becomes widespread to the east of the
Sioux Falls forecast area, we will have to watch for MVFR stratus
in rain cooled air backing into the forecast area late tonight and
early Wednesday.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&

SHORT TERM...MJ
LONG TERM...Ferguson/
AVIATION...MJ
Hazardous weather outlook, Jul 18, 5:04 AM CDT, 10 hours 3 minutes before
Hazardous Weather Outlook
National Weather Service Sioux Falls SD
504 AM CDT Tue Jul 18 2017

IAZ012-020>022-031-032-NEZ013-014-SDZ050-063>071-191015-
Sioux-Plymouth-Cherokee-Buena Vista-Woodbury-Ida-Dixon-Dakota-
Gregory-Charles Mix-Douglas-Hutchinson-Turner-Lincoln SD-
Bon Homme-Yankton-Clay SD-Union-
504 AM CDT Tue Jul 18 2017

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

.DAY ONE...Today and Tonight

Heat index values will once again approach 100 degrees in the
Missouri River Valley today.

Thunderstorms will be possible late this afternoon into this
evening. Best chances for storms will be east of the James River.
Hail to the size of half dollars, wind gusts to 65 mph, and an
isolated tornado will be possible with stronger storms. Heavy rain
will also be possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

The combination of heat and humidity will persist through mid-week,
with heat index values in the 90s to near 105 across the area
through Wednesday.

Thunderstorms chances will arrive almost daily this week, bringing
a potential for isolated strong to severe storms, as well as
locally heavy rainfall, to parts of the region through Friday. The
primary risks in thunderstorms will be damaging winds, along with
a large hail threat.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is likely after 5 pm.

SDZ038>040-052>054-057>060-191015-
Beadle-Kingsbury-Brookings-Jerauld-Sanborn-Miner-Brule-Aurora-
Davison-Hanson-
504 AM CDT Tue Jul 18 2017

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

.DAY ONE...Today and Tonight

Thunderstorms will be possible this morning. An isolated storm may
produce hail to the size of quarters or wind gust to 60 mph.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

The chance for mainly nighttime thunderstorms will bring a
potential for isolated strong to severe storms, as well as locally
heavy rainfall, to parts of the region through Friday. Although
areas near and to the north of Interstate 90 are currently more
favored to see storms, timing and location are uncertain. At this
time, the greatest risks for strong thunderstorms are focused on
Wednesday afternoon and evening, and again by Friday.

While afternoon temperatures will ultimately depend on the extent
of overnight thunderstorm activity, heat index values in the 90s
to lower 100s will be possible at times through the upcoming
week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is possible through noon today.

IAZ001>003-013-014-MNZ071-072-080-081-089-090-097-098-SDZ055-056-
061-062-191015-
Lyon IA-Osceola-Dickinson-O'Brien-Clay IA-Lincoln MN-Lyon MN-
Murray-Cottonwood-Nobles-Jackson-Pipestone-Rock-Lake-Moody-McCook-
Minnehaha-
504 AM CDT Tue Jul 18 2017

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

.DAY ONE...Today and Tonight

A complex of storms across northeast south Dakota may try to build
south through late morning into the early afternoon. Wind gusts
up to 60 mph and hail to the size of ping pong balls are possible
with the strongest storms. Heavy rainfall will also be possible.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

Nearly daily thunderstorm chances through Friday may bring the
risk of locally heavy rainfall and pockets of severe weather.
 At this time, the greatest risks for strong thunderstorms are
focused on Tuesday afternoon, Wednesday afternoon and evening,
and again by Friday. Damaging winds and large hail will be the
primary risks.

While afternoon temperatures will ultimately depend on the extent
of overnight thunderstorm activity, heat index values in the 90s
to lower 100s will be possible across mainly northwest Iowa.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is likely after 10 am this morning.

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 18, 3:07 PM CDTHeat AdvisoryFSDBuena Vista, Cherokee, Ida, Lyon, O'Brien, Plymouth and 2 more29 hr

Nearby

Heat Advisories in Iowa, 2017Heat Advisories in Nebraska, 2017Every heat advisory in 2017

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.