Severe Thunderstorm Warning 312, NWS Pittsburgh, PA

175 
WWUS51 KPBZ 211818
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
218 PM EDT Thu Oct 21 2021

PAC019-073-085-121-211830-
/O.CON.KPBZ.SV.W.0312.000000T0000Z-211021T1830Z/
Mercer PA-Venango PA-Lawrence PA-Butler PA-
218 PM EDT Thu Oct 21 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 230 PM EDT
FOR MERCER...WESTERN VENANGO...LAWRENCE AND NORTHWESTERN BUTLER
COUNTIES...

At 218 PM EDT, severe thunderstorms were located along a line
extending from near Greenville to near Oakwood, moving northeast at
55 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to trees and power lines, resulting in some 
         power outages.

Locations impacted include...
New Castle, Hermitage, Sharon, Grove City, Franklin, Sharpsville,
Greenville, Sugarcreek, Farrell, Slippery Rock, New Wilmington, and
Oakwood.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report severe weather by calling 412-262-1988, posting to 
the NWS Pittsburgh Facebook page, or using Twitter @NWSPITTSBURGH. 

&&

LAT...LON 4162 7975 4117 7977 4087 8052 4147 8052
      4149 8047 4149 8000 4162 7983
TIME...MOT...LOC 1818Z 230DEG 48KT 4135 8040 4100 8046 

HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH

$$

086 
WWUS51 KPBZ 211828
SVSPBZ

Severe Weather Statement
National Weather Service Pittsburgh PA
228 PM EDT Thu Oct 21 2021

PAC019-073-085-121-211838-
/O.EXP.KPBZ.SV.W.0312.000000T0000Z-211021T1830Z/
Mercer PA-Venango PA-Lawrence PA-Butler PA-
228 PM EDT Thu Oct 21 2021

...THE SEVERE THUNDERSTORM WARNING FOR MERCER...WESTERN VENANGO...
LAWRENCE AND NORTHWESTERN BUTLER COUNTIES WILL EXPIRE AT 230 PM
EDT...
            
The storms which prompted the warning have weakened below severe 
limits, therefore, the warning will be allowed to expire.  However 
gusty winds are still possible with these thunderstorms.

LAT...LON 4162 7975 4117 7977 4087 8052 4147 8052
      4149 8047 4149 8000 4162 7983
TIME...MOT...LOC 1828Z 231DEG 53KT 4141 8031 4106 8037 

$$

Area Forecast Discussion
National Weather Service Pittsburgh PA
1239 PM EDT Thu Oct 21 2021

.SYNOPSIS...
Showers and thunderstorms return this afternoon and evening with a
cold front. Winds will be gusty, with an isolated strong to severe
storm possible.

&&

.NEAR TERM /THROUGH TONIGHT/...
Sfc and coupled upper low pressure will sweep across the Great Lakes
toward northern New England through tonight, with the associated cold
front moving through the Upper Ohio River Valley this afternoon and
evening. A strengthening upper jet as the upper low pivots from a
positive to neutral tilt will further support the front in
developing showers and thunderstorms. Showers will quickly diminish
this evening with FROPA due to dry advection and increasing
subsidence.

An isolated strong to severe thunderstorm capable of producing
damaging wind will be possible along the broken line of storms ahead
of the front. This will be supported by strong shear and strong
winds aloft, but weak instability due to lack of strong
heating/deeper moisture should limit a more widespread wind threat.

As a longwave trough sets up over the Great Lakes tonight into
Friday, an additional shortwave may provide enough vertical motion to
promote localized light rain and/or drizzle early Friday morning
given a moist boundary layer.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
A series of shortwaves with their jet maxima will cross the region
Friday through Saturday as upper trough remains positioned over the
Great Lakes. Periods of mostly isolated showers are possible while
clouds remain fairly abundant. The lack of warming and insolation
plus remnant cold advection will keep area temperature a few degrees
below normal.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Surface low pressure is expected to deepen and slowly lift from the
Central Plains Sunday in response to a developing trough/jet moving
through the area. The associated warm front will lift northward into
the Ohio River Valley as flow aloft becomes more zonal, with
strengthening jet support and warm/moist advection leading to
increased stratiform rain chances Sunday afternoon into Monday.

The low and upper trough should cross the region Monday into Tuesday,
bringing widespread rain and slightly cooler temperature. Drier and
unseasonably warm should develop thereafter as notable ridging is
expected to build in advance of the next low pressure system.

&&

.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
A surface cold front is expected to cross the region west to east
this afternoon and evening, with a broken line of showers and
thunderstorms along and just ahead of its leading edge. Isolated gust
up to 40kt may be possible with the stronger storms, otherwise expect
a brief gust and slow veering of sfc wind to the W.

Convection will quickly diminish after FROPA due to cold, dry
advection. Additional shortwave pulses from the overhead trough
should encourage MVFR/IFR cig development and even patchy
sprinkles/drizzle. Timing and duration of these impacts are a little
uncertain as upper flow won't be oriented out of the favorable/more
typical NW.

.Outlook...
Periodic restrictions are expected through the weekend due to upper
troughing, with weak pulses creating localized brief rain chances.
More widespread restrictions and precipitation is likely late Sunday
into early next week with the next low pressure system.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

Hazardous Weather Outlook
National Weather Service Pittsburgh PA
241 AM EDT Thu Oct 21 2021

OHZ039>041-048>050-057>059-068-069-PAZ007>009-013>016-020>023-029-
031-073>076-WVZ001>004-012-021-509>514-220645-
Tuscarawas-Carroll-Columbiana-Coshocton-Harrison-Jefferson OH-
Muskingum-Guernsey-Belmont-Noble-Monroe-Mercer-Venango-Forest-
Lawrence-Butler-Clarion-Jefferson PA-Beaver-Allegheny-Armstrong-
Indiana-Washington-Greene-Westmoreland-
Higher Elevations of Westmoreland-Fayette-
Higher Elevations of Fayette-Hancock-Brooke-Ohio-Marshall-Wetzel-
Marion-Monongalia-
Ridges of Eastern Monongalia and Northwestern Preston-Preston-
Eastern Preston-Western Tucker-Eastern Tucker-
241 AM EDT Thu Oct 21 2021

This Hazardous Weather Outlook is for east central Ohio, western
Pennsylvania, and northern West Virginia.

.DAY ONE...Today and tonight.

Isolated strong to damaging wind gusts will be possible in the
strongest storms this afternoon and evening with a crossing cold
front.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

Hazardous weather is not expected at this time.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to Standard Operating Procedures.

Special Weather Statement
National Weather Service Pittsburgh PA
128 PM EDT Thu Oct 21 2021

OHZ041-211800-
Columbiana OH-
128 PM EDT Thu Oct 21 2021

...A STRONG THUNDERSTORM WILL IMPACT NORTHWESTERN COLUMBIANA COUNTY
THROUGH 200 PM EDT...

At 128 PM EDT, Doppler radar was tracking a strong thunderstorm over
Alliance, or 13 miles west of Salem, moving northeast at 40 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Salem, Columbiana, Leetonia, Homeworth, North Georgetown, and Winona.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

&&

LAT...LON 4090 8082 4090 8058 4080 8109 4090 8108
      4090 8090 4093 8089 4093 8082
TIME...MOT...LOC 1728Z 240DEG 49KT 4091 8111

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH