Alert archive / West Virginia / Tornado Watches in 2017

Tornado Watch 184

May 1, 20174 states

The Storm Prediction Center issued this tornado watch at May 1, 2017, 12:32 PM EDT for 4 states. It was in force for 4 hr.

The area

The outline as issued.

The facts

Issued
May 1, 2017, 12:32 PM EDT (16:32 UTC)
Expired
May 1, 2017, 4:49 PM EDT
In force
4 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
65 kt
All 46 counties

Garrett County, MD, Ashtabula County, OH, Belmont County, OH, Carroll County, OH, Columbiana County, OH, Harrison County, OH, Jefferson County, OH, Mahoning County, OH, Monroe County, OH, Trumbull County, OH, Washington County, OH, Allegheny County, PA, Armstrong County, PA, Beaver County, PA, Butler County, PA, Clarion County, PA, Crawford County, PA, Erie County, PA, Fayette County, PA, Forest County, PA, Greene County, PA, Indiana County, PA, Jefferson County, PA, Lawrence County, PA, Mercer County, PA, Venango County, PA, Washington County, PA, Westmoreland County, PA, Barbour County, WV, Brooke County, WV, Doddridge County, WV, Hancock County, WV, Harrison County, WV, Marion County, WV, Marshall County, WV, Monongalia County, WV, Ohio County, WV, Pleasants County, WV, Preston County, WV, Ritchie County, WV, Taylor County, WV, Tucker County, WV, Tyler County, WV, Wetzel County, WV, Wirt County, WV, Wood County, WV

The radar

The Pittsburgh radar (KPBZ), 32 km from the middle of the area, began a volume at 16:32 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
70%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

19 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
May 1, 12:37 PM EDTSevere Thunderstorm WarningPBZBelmont, Monroe, Noble38 min
May 1, 12:42 PM EDTSevere Thunderstorm WarningPBZCarroll, Columbiana, Coshocton, Harrison, Jefferson, Tuscarawas63 min
May 1, 12:51 PM EDTSevere Thunderstorm WarningPBZBelmont, Carroll, Guernsey, Harrison, Monroe, Noble and 1 more39 min
May 1, 1:22 PM EDTSevere Thunderstorm WarningPBZBelmont, Carroll, Harrison, Jefferson53 min
May 1, 1:35 PM EDTSevere Thunderstorm WarningPBZCarroll, Columbiana, Jefferson55 min
May 1, 1:45 PM EDTSevere Thunderstorm WarningCLEAshtabula, Trumbull60 min
May 1, 1:47 PM EDTSevere Thunderstorm WarningPBZMercer, Venango43 min
May 1, 2:05 PM EDTSevere Thunderstorm WarningPBZAllegheny, Beaver, Butler, Lawrence, Mercer, Venango and 1 more55 min
May 1, 2:11 PM EDTSevere Thunderstorm WarningPBZAllegheny, Greene, Washington49 min
May 1, 2:22 PM EDTSevere Thunderstorm WarningCLECrawford, Erie53 min
May 1, 2:26 PM EDTSevere Thunderstorm WarningPBZClarion, Forest, Mercer, Venango49 min
May 1, 2:29 PM EDTTornado WarningPBZBeaver, Butler31 min
May 1, 2:44 PM EDTSevere Thunderstorm WarningRLXDoddridge, Harrison, Taylor18 min
May 1, 2:47 PM EDTSevere Thunderstorm WarningPBZAllegheny, Armstrong, Butler, Clarion, Indiana, Venango and 1 more58 min
May 1, 2:50 PM EDTTornado WarningPBZArmstrong, Butler, Clarion, Venango25 min
May 1, 2:54 PM EDTSevere Thunderstorm WarningPBZAllegheny, Fayette, Greene, Washington, Westmoreland66 min
May 1, 3:10 PM EDTSevere Thunderstorm WarningPBZArmstrong, Clarion, Forest, Jefferson, Venango65 min
May 1, 3:19 PM EDTTornado WarningPBZClarion, Forest, Venango26 min
May 1, 3:34 PM EDTSevere Thunderstorm WarningPBZArmstrong, Clarion, Indiana, Jefferson, Westmoreland56 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Pittsburgh, PA (KAGC), launched 12:00Z, 4.5 hours before the alert went out and 26 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, Pittsburgh, PA at 12:00Z on 2017-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 11 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, Pittsburgh, PA at 12:00Z on 2017-05-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 217 square meters per square second.19395878Sfc1 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
11 J/kg
Mixed-layer CIN
-114 J/kg
Mixed-layer LCL
1435 m above ground
0-6 km bulk shear
55 kt
0-1 km storm-relative helicity
217 m²/s²
0-3 km storm-relative helicity
191 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

683 
WWUS20 KWNS 011631
SEL4  
SPC WW 011631
MDZ000-OHZ000-PAZ000-WVZ000-012300-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 184
NWS Storm Prediction Center Norman OK
1235 PM EDT Mon May 1 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Far western Maryland Panhandle
  Far eastern Ohio
  Western Pennsylvania
  Northern West Virginia

* Effective this Monday afternoon and evening from 1235 PM until
  700 PM EDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered damaging winds likely with isolated significant gusts
    to 75 mph possible

SUMMARY...Line of storms along a cold front will accelerate
east-northeast this afternoon with damaging winds and a couple
tornadoes as the primary hazards.

The tornado watch area is approximately along and 105 statute miles
either side of a line from 40 miles northwest of Wheeling WV to 25
miles northeast of Latrobe PA. For a complete depiction of the watch
see the associated watch outline update (WOUS64 KWNS WOU4).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and severe thunderstorms in and close to the watch
area. Persons in these areas should be on the lookout for
threatening weather conditions and listen for later statements
and possible warnings.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 24045.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 1, 11:59 AM EDTMesoscale DiscussionSPCGarrett2 hr
May 1, 4:36 PM EDTMesoscale DiscussionSPCAllegany84 min
May 1, 5:54 PM EDTSevere Thunderstorm WatchSPCAllegany, Baltimore, Carroll, Charles, Frederick, Harford and 5 more5 hr
May 1, 1:41 PM EDTMesoscale DiscussionSPCBedford, Blair, Cambria, Cameron, Centre, Clearfield and 15 more64 min
May 1, 2:12 PM EDTTornado WatchSPCBedford, Blair, Bradford, Cambria, Cameron, Centre and 23 more8 hr
May 1, 6:52 PM EDTSevere Thunderstorm WatchSPCPike, Wayne4 hr
May 1, 7:16 PM EDTMesoscale DiscussionSPCBucks, Chester, Delaware, Montgomery, Northampton, Philadelphia2 hr
May 1, 2:29 PM EDTMesoscale DiscussionSPCGreenbrier, Mercer, Monroe, Nicholas, Pendleton, Pocahontas and 3 more2 hr

Nearby

Tornado Watches in West Virginia, 2017Tornado Watches in Pennsylvania, 2017Tornado Watches in Ohio, 2017Every tornado watch 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.