Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2018

Severe Thunderstorm Warning 79, NWS State College, PA

August 7, 2018Lancaster County, Pennsylvania

NWS State College, PA issued this severe thunderstorm warning at Aug 7, 2018, 6:40 PM EDT for Lancaster County, Pennsylvania. It was in force for 35 min. 1 report 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: Aug 7, 2018, 6:40 PM EDT (22:40 UTC)
Expired: Aug 7, 2018, 7:15 PM EDT
In force: 35 min
Issued by: NWS State College, PA
Area: Storm-based polygon
Hail: 0.75 in
Wind: 60.0 mph

County Lancaster County, PA

The radar

The Philadelphia radar (KDIX), 136 km from the middle of the area, began a volume at 22:42 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
Aug 7, 6:50 PM EDT	TSTM WND DMG	1 Se East Earl, PA	TREES DOWN ON WIRES ON RESERVOIR ROAD

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 one storm report to this severe thunderstorm warning; the first came 10 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 nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.7 hours before the alert went out and 171 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: 1323 J/kg
Mixed-layer CIN: -69 J/kg
Mixed-layer LCL: 955 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 3 m²/s²
0-3 km storm-relative helicity: 48 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

374 
WUUS51 KCTP 072240
SVRCTP
PAC071-072315-
/O.NEW.KCTP.SV.W.0079.180807T2240Z-180807T2315Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service State College PA
640 PM EDT TUE AUG 7 2018

The National Weather Service in State College PA has issued a

* Severe Thunderstorm Warning for...
  East central Lancaster County in south central Pennsylvania...

* Until 715 PM EDT.

* At 640 PM EDT, a severe thunderstorm was located near Paradise,
  moving northeast at 20 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  New Holland, Leola, Paradise, Gap, Terre Hill, Churchtown,
  Bareville, Bowmansville, Intercourse, Christiana, Fivepointville,
  Blue Ball, Georgetown, Gordonville, Goodville, Bird-In-Hand and
  White Horse.

This includes The Pennsylvania Turnpike from mile markers 290 to 295.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Torrential rainfall is occurring with this storm, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 4010 7594 4004 7594 3996 7599 3993 7598
      3987 7611 4007 7621 4022 7600 4014 7587
TIME...MOT...LOC 2240Z 234DEG 17KT 4004 7607 

HAIL...<.75IN
WIND...60MPH
 
$$

La Corte

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 State College, PA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 7, 6:38 PM EDT, 2 minutes earlier.

Area forecast discussion, Aug 7, 6:38 PM EDT, 2 minutes before

Area Forecast Discussion
National Weather Service State College PA
638 PM EDT Tue Aug 7 2018

.SYNOPSIS...
Humid and stormy weather will continue through midweek with
strong to locally severe thunderstorms possible. Thursday looks
like a drier day before an unsettled pattern unfolds over the
weekend through early next week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Showers and thunderstorms will continue to move through the
region this afternoon along a boundary out ahead of the frontal
system. Some of the strongest cells have been severe with heavy
downpours. Due to the low flash flood guidance and that strong
anomalous PWATS, any heavy downpours from these storms could
cause minor flooding. Heat index values are certainly
contributing to the potential for strong storms. They are
highest through the far southeast. Expect showers and
thunderstorms to continue through mid evening. Latest HRRR is
doing a decent job matching convection and continues to have
these storms move through the region through 03Z.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM WEDNESDAY/...
Rain showers and convection will diminish slowly after sunset
with redevelopment again on Wednesday as the weakened frontal
boundary remains over the northeast US and an upper level trough
begins to swing over the Great Lakes.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Drier wx is likely on Thursday before an unsettled pattern
unfolds over the weekend through early next week. Models and
ensembles show a cut off low developing over the OH Valley
by the end of the weekend. Widespread precipitation is likely
to the east of the low along the Appalachians into early next
week with some potential for a heavy rainfall threat
considering slow system movement. The distribution and intensity
of the rainfall will be sensitive to the evolution of the upper
low/trough. This will be something to monitor in the coming days
especially given how wet it has been this summer.

&&

.AVIATION /22Z TUESDAY THROUGH SUNDAY/...
Scattered showers and thunderstorms could produce a brief
evening reduction in a few locations across eastern Pa. The
focus will then shift to areas of developing valley fog
overnight. Climatology suggests the valleys of northern Pa are
most susceptible to locally dense fog. However, increasing
clouds ahead of an approaching front could limit the radiational
cooling and fog potential across western Pa late tonight.
Across eastern Pa, mostly clear skies and a calm wind the entire
night could allow dense valley fog to form.

Any fog should dissipate between 13Z-15Z. However, numerous
showers and thunderstorms associated with an approaching front
will bring brief localized reductions Wed PM.

.Outlook...

Wed...Morning fog possible. Afternoon TSRA impacts possible.

Thu...Morning fog possible.

Fri-Sat...Scattered afternoon TSRA impacts possible.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

SYNOPSIS...Steinbugl
NEAR TERM...Ceru
SHORT TERM...Ceru/Tyburski
LONG TERM...Steinbugl
AVIATION...Fitzgerald/Martin

Hazardous weather outlook, Aug 7, 4:38 AM EDT, 14 hours 2 minutes before

Hazardous Weather Outlook
National Weather Service State College PA
438 AM EDT Tue Aug 7 2018

PAZ004>006-010>012-017>019-024>028-033>037-041-042-045-046-049>053-
056>059-063>066-080845-
Warren-McKean-Potter-Elk-Cameron-Northern Clinton-Clearfield-
Northern Centre-Southern Centre-Cambria-Blair-Huntingdon-Mifflin-
Juniata-Somerset-Bedford-Fulton-Franklin-Tioga-Northern Lycoming-
Sullivan-Southern Clinton-Southern Lycoming-Union-Snyder-Montour-
Northumberland-Columbia-Perry-Dauphin-Schuylkill-Lebanon-Cumberland-
Adams-York-Lancaster-
438 AM EDT Tue Aug 7 2018

This Hazardous Weather Outlook is for central Pennsylvania.

.DAY ONE...Today and Tonight.

Isolated strong to severe thunderstorms with gusty winds and heavy
downpours that could lead to localized flash flooding are possible
this afternoon.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday.

Isolated strong to severe thunderstorms with gusty winds and heavy
downpours are possible Wednesday afternoon.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Local storm report, Aug 7, 4:22 PM EDT, 2 hours 18 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
422 PM EDT TUE AUG 07 2018

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

0355 PM     TSTM WND DMG     MOUNT CARMEL            40.80N  76.41W
08/07/2018                   NORTHUMBERLAND     PA   911 CALL CENTER

            1 TREE DOWN IN MT CARMEL TOWNSHIP.

&&

EVENT NUMBER CTP1802103

JRB

Local storm report, Aug 7, 4:36 PM EDT, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
436 PM EDT TUE AUG 07 2018

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

0352 PM     TSTM WND DMG     ASHLAND                 40.87N  78.33W
08/07/2018                   CLEARFIELD         PA   911 CALL CENTER

            WIRES DOWN AT INTERSECTION OF RT 61 AND RT 54.

&&

EVENT NUMBER CTP1802104

JRB

Local storm report, Aug 7, 5:30 PM EDT, 1 hour 10 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
530 PM EDT TUE AUG 07 2018

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

0430 PM     TSTM WND DMG     MILLERSTOWN             40.28N  78.30W
08/07/2018                   BLAIR              PA   911 CALL CENTER

            MULTIPLE TREES DOWN.

&&

EVENT NUMBER CTP1802105

JRB

Local storm report, Aug 7, 5:31 PM EDT, 1 hour 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE STATE COLLEGE PA
531 PM EDT TUE AUG 07 2018

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

0447 PM     TSTM WND DMG     NEW BLOOMFIELD          40.42N  77.19W
08/07/2018                   PERRY              PA   911 CALL CENTER

            MULTIPLE TREES AND WIRES DOWN.

&&

EVENT NUMBER CTP1802106

JRB

Special weather statement, Aug 7, 5:46 PM EDT, 54 minutes before

Special Weather Statement
National Weather Service State College PA
546 PM EDT TUE AUG 7 2018

PAZ059-066-072215-
Lancaster PA-Lebanon PA-
546 PM EDT TUE AUG 7 2018

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF LANCASTER AND LEBANON
COUNTIES UNTIL 615 PM EDT...

At 545 PM EDT, Doppler radar indicated a strong thunderstorm over
Timber Hills, moving east at 25 mph.

Pea size hail and winds in excess of 40 mph are possible.

Locations impacted include...
Lebanon, Ephrata, Elizabethtown, Lititz, Palmyra, Manheim, Annville,
East Petersburg, Cornwall, Akron, Leola, Denver, Campbelltown,
Rothsville, Pleasant Hill, Lebanon South, Cleona, Brickerville,
Schaefferstown and Quentin.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Torrential rainfall is also occurring with this storm, and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

&&

LAT...LON 4007 7617 4015 7659 4019 7660 4020 7657
      4027 7660 4034 7656 4033 7617 4029 7612
TIME...MOT...LOC 2145Z 278DEG 20KT 4025 7649

KF

Special weather statement, Aug 7, 6:01 PM EDT, 39 minutes before

Special Weather Statement
National Weather Service State College PA
601 PM EDT TUE AUG 7 2018

PAZ066-072215-
Lancaster PA-
601 PM EDT TUE AUG 7 2018

...A STRONG THUNDERSTORM WILL AFFECT PARTS OF LANCASTER COUNTY UNTIL
615 PM EDT...

At 600 PM EDT, Doppler radar indicated a strong thunderstorm over
Quarryville, moving east at 20 mph.

Pea size hail, frequent lightning, torrential downpours and winds in
excess of 40 mph are possible.

Locations impacted include...
Quarryville, Wakefield, Atglen, Georgetown, Kirkwood, Little Britain
and Buck.

LAT...LON 3977 7626 3995 7622 3995 7599 3993 7598
      3993 7600 3987 7599 3987 7600 3985 7602
      3981 7603 3980 7605 3979 7604 3976 7606
      3976 7608 3973 7609
TIME...MOT...LOC 2200Z 278DEG 15KT 3986 7615

KF

The office that day

Everything else NWS State College, PA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 7, 12:34 PM EDT	Special Weather Statement	CTP	Lycoming	26 min
Aug 7, 1:38 PM EDT	Special Weather Statement	CTP	Sullivan	37 min
Aug 7, 1:47 PM EDT	Special Weather Statement	CTP	Montour	43 min
Aug 7, 1:52 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Montour, Northumberland, Union	53 min
Aug 7, 2:00 PM EDT	Special Weather Statement	CTP	Somerset	30 min
Aug 7, 2:24 PM EDT	Areal Flood Advisory	CTP	Somerset	2 hr
Aug 7, 2:33 PM EDT	Special Weather Statement	CTP	Sullivan	42 min
Aug 7, 2:34 PM EDT	Areal Flood Advisory	CTP	Montour, Northumberland, Union	3 hr
Aug 7, 2:43 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Montour, Northumberland	77 min
Aug 7, 2:54 PM EDT	Special Weather Statement	CTP	Dauphin	51 min
Aug 7, 3:07 PM EDT	Severe Thunderstorm Warning	CTP	Dauphin, Lebanon, Schuylkill	13 min
Aug 7, 3:26 PM EDT	Special Weather Statement	CTP	Fulton, Huntingdon	49 min
Aug 7, 3:36 PM EDT	Areal Flood Advisory	CTP	Snyder	114 min
Aug 7, 3:58 PM EDT	Special Weather Statement	CTP	Franklin	47 min
Aug 7, 4:03 PM EDT	Special Weather Statement	CTP	Dauphin	57 min
Aug 7, 4:20 PM EDT	Severe Thunderstorm Warning	CTP	Schuylkill	39 min
Aug 7, 4:29 PM EDT	Severe Thunderstorm Warning	CTP	Juniata, Perry	31 min
Aug 7, 5:46 PM EDT	Special Weather Statement	CTP	Lancaster	29 min
Aug 7, 6:01 PM EDT	Special Weather Statement	CTP	Lancaster	14 min
Aug 7, 6:14 PM EDT	Areal Flood Advisory	CTP	Lancaster, Lebanon	3 hr
Aug 7, 6:20 PM EDT	Areal Flood Advisory	CTP	Sullivan	3 hr
Aug 7, 6:58 PM EDT	Flash Flood Warning	CTP	Sullivan	3 hr
Aug 7, 7:11 PM EDT	Areal Flood Advisory	CTP	Lancaster	2 hr

Nearby

Severe Thunderstorm Warnings in Pennsylvania, 2018 Every severe thunderstorm warning in 2018

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.