Severe Thunderstorm Watch 431

Issued

Aug 12, 2021, 1:11 PM EDT (17:11 UTC)

Expired

Aug 12, 2021, 10:00 PM EDT

In force

9 hr

Issued by

the Storm Prediction Center

Largest hail expected

1 in

Strongest gust expected

60 kt

The State College radar (KCCX), 31 km from the middle of the area, began a volume at 17:12 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.

Two or more tornadoes

5%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

70%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

20%

One or more hailstones of 2 inches or more

5%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1498 Severe potential...watch possibleAug 12, 12:19 PM EDT
• Mesoscale Discussion 1503 Severe thunderstorm watch 431...433Aug 12, 6:22 PM EDT

153 
WWUS20 KWNS 121707
SEL1  
SPC WW 121707
PAZ000-130000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 431
NWS Storm Prediction Center Norman OK
110 PM EDT Thu Aug 12 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Much of central Pennsylvania

* Effective this Thursday afternoon and evening from 110 PM until
  800 PM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph likely
  Isolated large hail events to 1 inch in diameter possible

SUMMARY...Multiple clusters of storms are expected to intensify and
move eastward through the afternoon from west central into central
Pennsylvania.  The storm environment favors damaging winds of 60-70
mph as the primary threat, though isolated large hail near 1 inch
diameter may occur with the strongest storms.

The severe thunderstorm watch area is approximately along and 45
statute miles north and south of a line from 15 miles northwest of
Latrobe PA to 25 miles east southeast of Williamsport PA. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU1).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for 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. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
28030.

...Thompson

Severe Thunderstorm Watches in Pennsylvania, 2021Every severe thunderstorm watch in 2021

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.