Alert archive / Iowa / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 12, NWS Omaha, NE

March 6, 20174 counties in Iowa

NWS Omaha, NE issued this severe thunderstorm warning at Mar 6, 2017, 4:56 PM CST for 4 counties in Iowa. It was in force for 34 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Mar 6, 2017, 4:56 PM CST (22:56 UTC)
Expired: Mar 6, 2017, 5:30 PM CST
In force: 34 min
Issued by: NWS Omaha, NE
Area: Storm-based polygon
Hail: 1.0 in
Wind: 60.0 mph

Counties Fremont County, IA, Mills County, IA, Montgomery County, IA, Page County, IA

The radar

The Omaha radar (KOAX), 95 km from the middle of the area, began a volume at 22:58 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Mar 6, 1:54 PM CST	Tornado Watch	SPC	8 hr

The nearest sounding before it

Omaha, NE (KOAX), launched 12:00Z, 10.9 hours before the alert went out and 96 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 788 m above ground
0-6 km bulk shear: 47 kt
0-1 km storm-relative helicity: 437 m²/s²
0-3 km storm-relative helicity: 464 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Omaha, NE wrote its last area forecast discussion before this severe thunderstorm warning went out at Mar 6, 4:19 PM CST, 37 minutes earlier.

Area forecast discussion, Mar 6, 4:19 PM CST, 37 minutes before

Area Forecast Discussion
National Weather Service Omaha/Valley NE
419 PM CST Mon Mar 6 2017

.SHORT TERM...(tonight through Thursday)
Issued at 416 PM CST Mon Mar 6 2017

WV imagery this afternoon showing a positive tilt longwave trof
extending from western Canada down through the central Rockies
with a strong jet max...140kt...rounding the base. Meanwhile deep
surface low pressure was situated over eastern North Dakota with a
distinct dryline extending southward along the surface trof. Bit
further upstream...attendant cold front cutting through quickly
sweeping in through central South Dakota into eastern Colorado.
12z PWS plot indicated ample moisture on tap with values of 225%
above normal.

Thunderstorm activity is already firing along the dryline over the
CWA and moving into increasingly unstable environment...SB CAPES
2000J/KG. Deep shear quite impressive as well with 0-6km shear
values approaching 70kt. Expect activity to increase over the next
several hours along the I-80 corridor where boundary layer theta-E
convergence is progged to strengthen. Given the tremendous
environmental shear...there is a distinct possibility for severe
storms with large hail and perhaps one or two tornadic storms
through early evening over our entire IA CWA as well as extreme
southeast Nebraska.

Wednesday and Thursday...dry conditions and quiet weather expected
as  large scale flow deamplifies somewhat with a weak upstream ridge
over the western CONUS and upper trof off the east coast.

.LONG TERM...(Thursday night through Monday)
Issued at 416 PM CST Mon Mar 6 2017

Next round of possible precipitation comes Friday night/Saturday
associated with a Pacific Northwest shortwave trof dropping into the
central Plains. ECM/GFS/CMC all in pretty good agreement activity
will occur along axis of strong mid layer ageostrophic forcing
extending from the Black Hills into the Mid MS Valley.
Precipitation type will likely be an issue with with enough cold
air filtering in from the north to provide a rain/snow
mix...mainly over the southern CWA. Another Pacific Northwest
shortwave coming early next week will bring precipitation chances
to the region.

&&

.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1127 AM CST Mon Mar 6 2017

An intense surface low located along the SD-ND border north of
KABR as of 17z will develop northeast while an associated dryline
surges east through the mid MO Valley. With the passage of this
boundary, strong south winds will veer to southwest and then west
with gusts to 40-50 kt possible. Some relaxation of the surface
gradient is expected later tonight. Otherwise, expect VFR
conditions to prevail through the forecast period.

&&

.FIRE WEATHER...
Issued at 416 PM CST Mon Mar 6 2017

NAM12/GFS20/CMC are all indicating conditions will be favorable
again on Tuesday for extreme fire behavior over the Neb CWA and
possibly the IA CWA. All this in part to abundant dry
fuels...minimum RH 15-20%...and westerly wind gusts 25-35mph. Thus
will upgrade the Neb CWA to a Red Flag Warning and introduce a
Fire Weather Watch over the IA CWA.

&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Red Flag Warning until 8 PM CST this evening for NEZ011-012-
     015>018-030>034-042>045-050>053-065>068-078-088>093.

     Wind Advisory until 8 PM CST this evening for NEZ011-012-015>018-
     030>034-042>045-050>053-065>068-078-088>093.

     Red Flag Warning from 11 AM to 7 PM CST Tuesday for NEZ011-012-
     015>018-030>034-042>045-050>053-065>068-078-088>093.

IA...Red Flag Warning until 8 PM CST this evening for IAZ043-055-056-
     069-079-080-090-091.

     Fire Weather Watch from Tuesday morning through Tuesday evening
     for IAZ043-055-056-069-079-080-090-091.

     Wind Advisory until 8 PM CST this evening for IAZ043-055-056-069-
     079-080-090-091.

&&

SHORT TERM...DEE
LONG TERM...DEE
AVIATION...Mead
FIRE WEATHER...DEE

Hazardous weather outlook, Mar 6, 4:53 PM CST, 3 minutes before

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In the hours before

Local storm report, Mar 6, 4:17 PM CST, 39 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
417 PM CST MON MAR 06 2017

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

0415 PM     HAIL             AVOCA                   41.48N 95.34W
03/06/2017  E1.00 INCH       POTTAWATTAMIE      IA   FIRE DEPT/RESCUE

            AVOCA FIRE DEPARTMENT REPORTED HAIL ONGOING UP TO 1 INCH.
            WINDS UNDER 50 MPH.

&&

BMAYES

Local storm report, Mar 6, 4:19 PM CST, 37 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
419 PM CST MON MAR 06 2017

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

0345 PM     HAIL             8 ESE MISSOURI VALLEY   41.52N 95.75W
03/06/2017  E1.00 INCH       HARRISON           IA   PUBLIC

            HAIL UP TO 1 INCH JUST SOUTH OF BEEBEETOWN. TIME
            ESTIMATED.

&&

BMAYES

Local storm report, Mar 6, 4:22 PM CST, 34 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
422 PM CST MON MAR 06 2017

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

0415 PM     HAIL             AVOCA                   40.80N 96.12W
03/06/2017  E1.00 INCH       CASS               NE   FIRE DEPT/RESCUE

            AVOCA FIRE DEPARTMENT REPORTED HAIL ONGOING UP TO 1 INCH.
            WINDS UNDER 50 MPH.

&&

BMAYES

Local storm report, Mar 6, 4:35 PM CST, 21 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
435 PM CST MON MAR 06 2017

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

0309 PM     NON-TSTM WND GST OFFUTT AFB              41.11N 95.92W
03/06/2017  M57 MPH          SARPY              NE   TRAINED SPOTTER

            WEATHER STATION AT AIR FORCE 557TH WEATHER WING MEASURED
            WIND GUST BEFORE THUNDERSTORMS.

&&

BMAYES

Local storm report, Mar 6, 4:39 PM CST, 17 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE OMAHA/VALLEY NEBRASKA
439 PM CST MON MAR 06 2017

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

0435 PM     HAIL             2 SW TECUMSEH           40.35N 96.22W
03/06/2017  E0.88 INCH       JOHNSON            NE   TRAINED SPOTTER

            UP TO DIME TO NICKEL SIZE HAIL.

&&

BMAYES

Special weather statement, Mar 6, 4:46 PM CST, 10 minutes before

Special Weather Statement
National Weather Service Omaha/Valley Nebraska
446 PM CST MON MAR 6 2017

IAZ069-079-080-090-NEZ067-068-090>093-062315-
Pottawattamie IA-Mills IA-Fremont IA-Montgomery IA-Cass NE-Otoe NE-
Pawnee NE-Johnson NE-Nemaha NE-Richardson NE-
446 PM CST MON MAR 6 2017

...Significant Weather Advisory for FREMONT...NORTHWESTERN
MONTGOMERY...MILLS...EASTERN POTTAWATTAMIE...EASTERN JOHNSON...
WESTERN NEMAHA...EASTERN OTOE...NORTHWESTERN RICHARDSON...
NORTHEASTERN PAWNEE AND SOUTHEASTERN CASS COUNTIES UNTIL 515 PM
CST...

At 445 PM CST, Doppler radar was tracking a strong thunderstorm 9
miles northwest of Sidney, or 31 miles southeast of Omaha, moving
northeast at 55 mph. Another strong storm was located 7 miles
northeast of Tecumseh, also moving northeast at 55 mph.

Nickel size hail and wind gusts of 50 to 55 mph will be possible with
this storm.

Locations impacted include...
Nebraska City, Auburn, Tecumseh, Oakland, Hamburg, Malvern, Sidney,
Carson, Emerson, Johnson, Macedonia, Talmage, Lorton, Tabor, Silver
City, Thurman, Hancock, Henderson, Randolph and Hastings.

This includes the following highways...
 Highway 136 in Nebraska between mile markers 211 and 230.
 Highway 2 in Nebraska between mile markers 502 and 508.
 Highway 34 in Iowa between mile markers 11 and 30.
 Highway 59 in Iowa between mile markers 28 and 61.
 Highway 75 in Nebraska between mile markers 26 and 54.
 Interstate 29 between mile markers 1 and 24.

A tornado watch remains in effect until 1000 PM CST for southwestern
Iowa. A tornado watch also remains in effect until 1000 PM CST for
southeastern Nebraska.

LAT...LON 4058 9567 4058 9578 4053 9577 4053 9571
      4026 9591 4026 9628 4146 9538 4147 9523
      4127 9515
TIME...MOT...LOC 2245Z 237DEG 55KT 4087 9572

MEAD

The office that day

Everything else NWS Omaha, NE issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 6, 2:46 AM CST	Fire Weather Watch	OAX	Antelope, Boone, Burt, Butler, Cass, Cedar and 24 more	14 hr
Mar 6, 1:52 PM CST	Severe Thunderstorm Warning	OAX	Burt, Cuming, Dodge	23 min
Mar 6, 1:57 PM CST	Special Weather Statement	OAX	Dodge	48 min
Mar 6, 2:09 PM CST	Severe Thunderstorm Warning	OAX	Burt, Thurston	36 min
Mar 6, 2:21 PM CST	Special Weather Statement	OAX	Dodge	24 min
Mar 6, 2:27 PM CST	Special Weather Statement	OAX	Saunders	33 min
Mar 6, 2:50 PM CST	Special Weather Statement	OAX	Douglas, Washington	25 min
Mar 6, 2:56 PM CST	Severe Thunderstorm Warning	OAX	Douglas, Sarpy, Saunders	34 min
Mar 6, 3:16 PM CST	Special Weather Statement	OAX	Cass	29 min
Mar 6, 3:20 PM CST	Severe Thunderstorm Warning	OAX	Douglas, Washington	25 min
Mar 6, 3:25 PM CST	Severe Thunderstorm Warning	OAX	Douglas, Sarpy	35 min
Mar 6, 3:38 PM CST	Severe Thunderstorm Warning	OAX	Douglas, Washington	37 min
Mar 6, 3:47 PM CST	Severe Thunderstorm Warning	OAX	Douglas, Sarpy	28 min
Mar 6, 3:53 PM CST	Special Weather Statement	OAX	Cass, Johnson, Otoe	22 min
Mar 6, 3:55 PM CST	Special Weather Statement	OAX	Gage	35 min
Mar 6, 4:09 PM CST	Severe Thunderstorm Warning	OAX	Cass, Gage, Johnson, Lancaster, Nemaha, Otoe and 2 more	36 min
Mar 6, 4:32 PM CST	Red Flag Warning	OAX	Antelope, Boone, Burt, Butler, Cass, Cedar and 24 more	25 hr
Mar 6, 4:46 PM CST	Special Weather Statement	OAX	Nemaha	29 min
Mar 6, 4:53 PM CST	Severe Thunderstorm Warning	OAX	Johnson, Nemaha, Otoe	37 min
Mar 6, 5:08 PM CST	Special Weather Statement	OAX	Pawnee	37 min
Mar 6, 5:35 PM CST	Special Weather Statement	OAX	Richardson	40 min
Mar 6, 5:41 PM CST	Severe Thunderstorm Warning	OAX	Nemaha, Richardson	34 min
Mar 6, 2:40 PM CST	Severe Thunderstorm Warning	OAX	Monona	35 min
Mar 6, 4:02 PM CST	Severe Thunderstorm Warning	OAX	Harrison, Pottawattamie, Shelby	28 min
Mar 6, 4:32 PM CST	Fire Weather Watch	OAX	Fremont, Harrison, Mills, Monona, Montgomery, Page and 2 more	11 hr
Mar 6, 5:06 PM CST	Severe Thunderstorm Warning	OAX	Fremont, Page	24 min
Mar 6, 5:19 PM CST	Severe Thunderstorm Warning	OAX	Montgomery	26 min
Mar 6, 5:29 PM CST	Severe Thunderstorm Warning	OAX	Fremont, Montgomery, Page	31 min
Mar 6, 5:39 PM CST	Severe Thunderstorm Warning	OAX	Montgomery	21 min
Mar 6, 5:51 PM CST	Tornado Warning	OAX	Page	24 min
Mar 6, 5:59 PM CST	Tornado Warning	OAX	Page	16 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2017 Every severe thunderstorm warning 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.