Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 301, NWS Tulsa, OK

May 27, 2017Nowata County, Washington County, Oklahoma

NWS Tulsa, OK issued this severe thunderstorm warning at May 27, 2017, 6:58 PM CDT for Nowata County, Washington County, Oklahoma. It was in force for 62 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: May 27, 2017, 6:58 PM CDT (23:58 UTC)
Expired: May 27, 2017, 8:00 PM CDT
In force: 62 min
Issued by: NWS Tulsa, OK
Area: Storm-based polygon
Hail: 1.25 in
Wind: 60.0 mph

Counties Nowata County, OK, Washington County, OK

The radar

The Tulsa radar (KINX), 77 km from the middle of the area, began a volume at 00:00 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.

What was reported inside it

Time	Report	Where	Remark
May 27, 7:03 PM CDT	HAIL 1	9 Wnw Nowata, OK
May 27, 7:16 PM CDT	HAIL 1.75	Nowata, OK	SOCIAL MEDIA REPORT.
May 27, 7:22 PM CDT	HAIL 1.25	1 S Nowata, OK

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

Did it verify

Verified. The Iowa Environmental Mesonet's Cow matched 3 storm reports to this severe thunderstorm warning; the first came 5 minutes after it went out.

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

The watch it was issued in

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

Issued	Product	Office	Lasted
May 27, 4:01 PM CDT	Tornado Watch	SPC	10 hr

The nearest sounding before it

Springfield, MO (KSGF), launched 12:00Z, 12.0 hours before the alert went out and 165 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: 3187 J/kg
Mixed-layer CIN: -48 J/kg
Mixed-layer LCL: 766 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 127 m²/s²
0-3 km storm-relative helicity: 138 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 9.6

Open this sounding in Storm Lab

The text

As transmitted.

976 
WUUS54 KTSA 272358
SVRTSA
OKC105-147-280100-
/O.NEW.KTSA.SV.W.0301.170527T2358Z-170528T0100Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Tulsa OK
658 PM CDT SAT MAY 27 2017

The National Weather Service in Tulsa has issued a

* Severe Thunderstorm Warning for...
  Washington County in northeastern Oklahoma...
  Nowata County in northeastern Oklahoma...

* Until 800 PM CDT

* At 658 PM CDT, a severe thunderstorm was located near Copan, 
  moving northeast at 40 mph. Another severe thunderstorm was 
  located 5 miles southeast of Bartlesville...moving east at 35 mph. 

  HAZARD...60 mph wind gusts and half dollar size hail. 

  SOURCE...Radar indicated. 

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees. 

* Locations in or near the path include...
  Bartlesville...                   Nowata...
  Dewey...                          South Coffeyville...
  Copan...                          Ochelata...
  Delaware...                       Lenapah...
  Wann...                           New Alluwe...
  Watova...                         

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

A tornado watch remains in effect until midnight CDT for northeastern
Oklahoma.

LAT...LON 3699 9543 3660 9543 3660 9600 3689 9600
      3700 9586 3700 9544
TIME...MOT...LOC 2358Z 235DEG 35KT 3686 9591 

HAIL...1.25IN
WIND...60MPH
 
$$

69

3 follow-up statements

169 
WWUS54 KTSA 280010
SVSTSA

Severe Weather Statement
National Weather Service Tulsa OK
710 PM CDT SAT MAY 27 2017

OKC105-147-280100-
/O.CON.KTSA.SV.W.0301.000000T0000Z-170528T0100Z/
Washington OK-Nowata OK-
710 PM CDT SAT MAY 27 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR EAST CENTRAL WASHINGTON AND SOUTHERN NOWATA COUNTIES...

At 710 PM CDT, a severe thunderstorm was located 7 miles west of
Watova, moving east at 45 mph.

HAZARD...60 mph wind gusts and half dollar size hail. 

SOURCE...Radar indicated. 

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees. 

Locations in or near the path include...
Bartlesville...                   Nowata...
Delaware...                       New Alluwe...
Watova...                         

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

A tornado watch remains in effect until midnight CDT for northeastern
Oklahoma.

LAT...LON 3689 9543 3660 9543 3660 9586 3674 9590
TIME...MOT...LOC 0010Z 281DEG 39KT 3664 9578 

TORNADO...POSSIBLE
HAIL...1.25IN
WIND...60MPH
 
$$

69

363 
WWUS54 KTSA 280029
SVSTSA

Severe Weather Statement
National Weather Service Tulsa OK
729 PM CDT SAT MAY 27 2017

OKC147-280039-
/O.CAN.KTSA.SV.W.0301.000000T0000Z-170528T0100Z/
Washington OK-
729 PM CDT SAT MAY 27 2017

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL WASHINGTON COUNTY
IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. therefore the warning has been cancelled.

A tornado watch remains in effect until midnight CDT for northeastern
Oklahoma.

LAT...LON 3675 9543 3660 9543 3660 9574 3673 9566
TIME...MOT...LOC 0029Z 284DEG 34KT 3661 9557 

$$

OKC105-280100-
/O.CON.KTSA.SV.W.0301.000000T0000Z-170528T0100Z/
Nowata OK-
729 PM CDT SAT MAY 27 2017

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 800 PM CDT
FOR SOUTHEASTERN NOWATA COUNTY...

At 729 PM CDT, a severe thunderstorm was located 4 miles west of New
Alluwe, moving east at 40 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts. 

SOURCE...Radar indicated. 

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees. 

Locations in or near the path include...
Nowata...                         New Alluwe...
Watova...                         

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

A tornado watch remains in effect until midnight CDT for northeastern
Oklahoma.

LAT...LON 3675 9543 3660 9543 3660 9574 3673 9566
TIME...MOT...LOC 0029Z 284DEG 34KT 3661 9557 

HAIL...1.75IN
WIND...60MPH
 
$$

69

014 
WWUS54 KTSA 280100
SVSTSA

Severe Weather Statement
National Weather Service Tulsa OK
800 PM CDT SAT MAY 27 2017

OKC105-280110-
/O.EXP.KTSA.SV.W.0301.000000T0000Z-170528T0100Z/
Nowata OK-
800 PM CDT SAT MAY 27 2017

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN NOWATA COUNTY HAS
EXPIRED...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning has been allowed to expire.

A tornado watch remains in effect until midnight CDT for northeastern
Oklahoma.

LAT...LON 3675 9543 3660 9543 3660 9574 3673 9566
TIME...MOT...LOC 0100Z 235DEG 35KT 3677 9528 

$$

69

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 Tulsa, OK wrote its last area forecast discussion before this severe thunderstorm warning went out at May 27, 5:20 PM CDT, 1 hour 38 minutes earlier.

Area forecast discussion, May 27, 5:20 PM CDT, 1 hour 38 minutes before

Area Forecast Discussion
National Weather Service Tulsa OK
520 PM CDT Sat May 27 2017

.DISCUSSION...

The 00Z TAF discussion is included below.

&&

.AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
An extremely unstable airmass over the region ahead of a cold
front and dryline will set the stage for numerous severe
thunderstorms over the region this TAF period. The most likely
time window at each site was the time frame used in the Tempo
groups. VFR conditions will prevail outside of storms this
evening, with IFR potential if storms hit the airports. MVFR and
possibly even IFR cigs will overspread the region behind the
front, with a trend toward VFR on Sunday as cooler and drier air
in the low levels moves into the region.

Lacy

&&

.PREV DISCUSSION... /Issued 259 PM CDT Sat May 27 2017/

DISCUSSION...
Conditions are prime for significant severe weather later this
afternoon and overnight across eastern Oklahoma and northwest
Arkansas. Extreme instability is currently in place and effective
shear values are supportive of organized updrafts. These
conditions will support all modes of severe weather including
destructive winds, giant hail, and possibly a few strong
tornadoes.

The details on how the eventual convection evolves are less clear
however a likely scenario is of supercells initiating both along
the boundary from NE OK into far NW AR, and further south
along the dryline in south central OK. Currently expanding mid
cloud across central OK is likely a zone of enhanced lift yet to
overspread the region. The capping inversion has continued to
weaken and any further lift along with localized sfc convergence
is expected to spark storm development. Storms further south along
the dryline may be more delayed in development but nevertheless
will also pose significant severe weather potential. The severe
weather threat will continue into the overnight hours awaiting
the passing cold front to clear the area from northwest to
southeast.

The remainder of the forecast is expected to be rather tranquil as
dry weather prevails for early week with increasing thunderstorm
chances for mid to late week. Flow aloft is forecast to weaken
considerably as the westerlies lift well north thus reducing the
severe weather potential.

&&

.PRELIMINARY POINT TEMPS/POPS...
TUL   65  81  58  87 /  60  10   0   0
FSM   71  83  60  87 /  70  10   0   0
MLC   67  80  57  86 /  70  10   0   0
BVO   62  81  53  87 /  40  10   0  10
FYV   64  77  51  82 /  70  10   0   0
BYV   66  78  54  82 /  70  10   0   0
MKO   66  79  57  86 /  70  10   0   0
MIO   64  80  54  84 /  60  10   0  10
F10   66  80  57  86 /  60  10   0   0
HHW   71  81  61  87 /  80  20  10  10

&&

.TSA WATCHES/WARNINGS/ADVISORIES...
OK...Flood Watch through Sunday morning for OKZ049-053-067>076.

AR...Flood Watch through Sunday morning for ARZ001-002-010-011-019-
     020-029.

&&

AVIATION...30

Hazardous weather outlook, May 27, 4:57 PM CDT, 2 hours 1 minute before

Hazardous Weather Outlook
National Weather Service Tulsa OK
457 PM CDT Sat May 27 2017

ARZ001-002-010-011-019-020-029-OKZ049-053>076-281030-
Adair OK-Benton AR-Carroll AR-Cherokee OK-Choctaw OK-Craig OK-
Crawford AR-Creek OK-Delaware OK-Franklin AR-Haskell OK-Latimer OK-
Le Flore OK-Madison AR-Mayes OK-McIntosh OK-Muskogee OK-Nowata OK-
Okfuskee OK-Okmulgee OK-Osage OK-Ottawa OK-Pawnee OK-Pittsburg OK-
Pushmataha OK-Rogers OK-Sebastian AR-Sequoyah OK-Tulsa OK-Wagoner OK-
Washington OK-Washington AR-
457 PM CDT Sat May 27 2017

...TORNADO WATCH IN EFFECT UNTIL MIDNIGHT FOR EASTERN OKLAHOMA
AND WESTERN ARKANSAS...

...SIGNIFICANT SEVERE WEATHER LIKELY TONIGHT WITH DESTRUCTIVE
WINDS AND LARGE HAIL WITH A FEW STRONG TORNADOES POSSIBLE...

This Outlook is for Northwest and West Central Arkansas as well as
much of Eastern Oklahoma.

.DAY ONE...This afternoon and Tonight.
TORNADO.
	RISK...Elevated.
	AREA...Eastern Oklahoma and western Arkansas.
	ONSET...Late afternoon.

SEVERE THUNDERSTORM.
	RISK...Critical.
	AREA...Eastern Oklahoma and western Arkansas.
    ONSET...Late afternoon.

	AREA AT GREATEST RISK...Along and north of Interstate 44 through early evening,
    then along and south of Interstate 44 tonight.

FLASH FLOOD.
	RISK...Limited.
	AREA...Eastern Oklahoma and western Arkansas.
	ONSET...Early evening.

HEAVY RAIN.
	RISK...Limited.
	AREA...Eastern Oklahoma and western Arkansas.
	ONSET...Early evening.

DANGEROUS HEAT.
	RISK...Limited.
	AREA...Eastern Oklahoma and Western Arkansas.
	ONSET...Ongoing.

DISCUSSION...
Latest surface mesoanalysis shows boundary across far northeast
Oklahoma. OK mesonet observations and radar data suggest
convective towers are developing along a line from just north of
Vinita southwest toward central Osage County - near Pawhuska. We
are monitoring this area for first development this afternoon.

Elevated showers and storms are approaching from central Oklahoma
with a few lightning strikes noted. The cap has held strong to
this point but once the cap is breached, explosive storm
development is likely given extreme instability in place. All
modes of severe will be likely, including very large hail,
damaging wind gusts and tornadoes.

Eventually, storms will increase in coverage and likely
transition toward a damaging wind threat by mid to late evening as
they develop southeastward. Additionally, an axis of heavy
rainfall is likely from northwest Arkansas through eastern
Oklahoma. Recent heavy rainfall may allow for rapid onset flash
flooding in a few locations.

SPOTTER AND EMERGENCY MANAGEMENT ACTION STATEMENT...
Regional Spotter Network has been activated.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.
SUNDAY...Thunderstorm Potential.
MONDAY and TUESDAY...No Hazards.
WEDNESDAY through FRIDAY...Thunderstorm Potential.

EXTENDED DISCUSSION...
Storms will begin to shift southeast of the region Sunday morning
with dry conditions on Monday and Tuesday. Low thunderstorm
chances return mid to late week, with limited additional severe
weather potential.

EMERGENCY MANAGEMENT PLANNING STATEMENT...
A Tornado Watch is in effect through midnight for all of eastern
Oklahoma and western Arkansas. Initiation of storms is expected
within the next hour or so. The holiday weekend will provide
numerous outdoor exposures which will further increase the
potential for a rapid safety response. Outdoor activities may need
to be cancelled this evening, especially if you are unable to
quickly move indoors to a substantial shelter.

weather.gov/tulsa Contains additional information.

CORFIDI

In the hours before

Local storm report, May 27, 5:50 PM CDT, 1 hour 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
550 PM CDT SAT MAY 27 2017

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

0546 PM     HAIL             6 W MIAMI               36.87N 94.99W
05/27/2017  E0.88 INCH       OTTAWA             OK   STORM CHASER

&&

SFP

Local storm report, May 27, 6:34 PM CDT, 24 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
634 PM CDT SAT MAY 27 2017

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

0630 PM     HAIL             OSAGE HILLS STATE PARK  36.74N 96.18W
05/27/2017  E1.75 INCH       OSAGE              OK   PARK/FOREST SRVC

&&

JDS

Local storm report, May 27, 6:46 PM CDT, 12 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
646 PM CDT SAT MAY 27 2017

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

0645 PM     HAIL             WYANDOTTE               36.79N 94.72W
05/27/2017  E1.75 INCH       OTTAWA             OK   EMERGENCY MNGR

&&

JDS

Local storm report, May 27, 6:55 PM CDT, 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TULSA OK
655 PM CDT SAT MAY 27 2017

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

0651 PM     HAIL             BARTLESVILLE            36.75N 95.98W
05/27/2017  E1.25 INCH       WASHINGTON         OK   TRAINED SPOTTER

            NEAR THE AIRPORT. SOME DAMAGE TO A VEHICLE AND ROOF AT A
            HOME.

&&

JDS

The office that day

Everything else NWS Tulsa, OK issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 26, 10:25 PM CDT	Special Weather Statement	TSA	Muskogee	50 min
May 26, 10:32 PM CDT	Special Weather Statement	TSA	McIntosh	43 min
May 27, 2:47 PM CDT	Flood Watch	TSA	Adair, Cherokee, Choctaw, Haskell, Latimer, McIntosh and 4 more	14 hr
May 27, 5:17 PM CDT	Severe Thunderstorm Warning	TSA	Craig, Ottawa	43 min
May 27, 5:25 PM CDT	Tornado Warning	TSA	Craig, Ottawa	35 min
May 27, 5:36 PM CDT	Severe Thunderstorm Warning	TSA	Craig, Ottawa	54 min
May 27, 5:56 PM CDT	Severe Thunderstorm Warning	TSA	Craig, Ottawa	34 min
May 27, 6:14 PM CDT	Areal Flood Advisory	TSA	Craig, Ottawa	3 hr
May 27, 6:16 PM CDT	Severe Thunderstorm Warning	TSA	Osage, Washington	44 min
May 27, 6:30 PM CDT	Severe Thunderstorm Warning	TSA	Ottawa	45 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.