Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 23, NWS State College, PA

August 27, 2021Lancaster County, Pennsylvania

NWS State College, PA issued this flash flood warning at Aug 27, 2021, 6:07 PM EDT for Lancaster County, Pennsylvania. It was in force for 60 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Aug 27, 2021, 6:07 PM EDT (22:07 UTC)
Expired: Aug 27, 2021, 7:07 PM EDT
In force: 60 min
Issued by: NWS State College, PA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Lancaster County, PA

The radar

The Dover AFB radar (KDOX), 152 km from the middle of the area, began a volume at 22:08 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.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.1 hours before the alert went out and 158 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: 780 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 983 m above ground
0-6 km bulk shear: 8 kt
0-1 km storm-relative helicity: 13 m²/s²
0-3 km storm-relative helicity: 41 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

569 
WGUS51 KCTP 272207
FFWCTP
PAC071-280015-
/O.NEW.KCTP.FF.W.0023.210827T2207Z-210828T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service State College PA
607 PM EDT Fri Aug 27 2021

The National Weather Service in State College has issued a

* Flash Flood Warning for...
  Central Lancaster County in south central Pennsylvania...

* Until 815 PM EDT.

* At 607 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 2 inches of rain 
  have fallen. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Lancaster, Ephrata, Lititz, Willow Street, New Holland, East 
  Petersburg, Akron, Leola, Paradise, Rothsville, Strasburg, 
  Quarryville, Leacock, Bareville, Smithville, Lampeter, 
  Intercourse, Farmersville, Gordonville and Bird-In-Hand.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4013 7634 4021 7618 4014 7608 3985 7610
      3982 7630

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Colbert

1 follow-up statement

694 
WGUS71 KCTP 272307 RRA
FFSCTP

Flash Flood Statement
National Weather Service State College PA
707 PM EDT Fri Aug 27 2021

PAC071-272317-
/O.CAN.KCTP.FF.W.0023.000000T0000Z-210828T0015Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Lancaster PA-
707 PM EDT Fri Aug 27 2021

...FLASH FLOOD WARNING IS CANCELLED FOR CENTRAL LANCASTER COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

A Flash Flood Watch remains in effect until 100 AM EDT for a portion 
of central Pennsylvania.

LAT...LON 4013 7634 4021 7618 4014 7608 3985 7610
      3982 7630

$$

CR

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 27, 4:40 AM EDT	Flash Flood Watch	CTP	Dauphin, Lancaster, Lebanon, York	17 hr
Aug 27, 2:13 PM EDT	Areal Flood Advisory	CTP	Potter	2 hr
Aug 27, 3:10 PM EDT	Special Weather Statement	CTP	York	35 min
Aug 27, 3:37 PM EDT	Special Weather Statement	CTP	Juniata	38 min
Aug 27, 4:13 PM EDT	Special Weather Statement	CTP	Tioga	32 min
Aug 27, 4:29 PM EDT	Areal Flood Advisory	CTP	Tioga	2 hr
Aug 27, 4:34 PM EDT	Areal Flood Advisory	CTP	Columbia, Northumberland, Schuylkill	2 hr
Aug 27, 4:50 PM EDT	Areal Flood Advisory	CTP	Lancaster, York	115 min
Aug 27, 4:55 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Tioga	99 min
Aug 27, 5:02 PM EDT	Special Weather Statement	CTP	York	28 min
Aug 27, 5:11 PM EDT	Special Weather Statement	CTP	Lancaster	49 min
Aug 27, 5:13 PM EDT	Special Weather Statement	CTP	Dauphin	47 min
Aug 27, 5:16 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	59 min
Aug 27, 5:38 PM EDT	Areal Flood Advisory	CTP	Dauphin, Lebanon	2 hr
Aug 27, 5:46 PM EDT	Areal Flood Advisory	CTP	Lancaster, Lebanon	80 min
Aug 27, 5:57 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Dauphin	70 min
Aug 27, 6:05 PM EDT	Special Weather Statement	CTP	Lebanon	25 min
Aug 27, 6:18 PM EDT	Areal Flood Advisory	CTP	Dauphin, Lebanon, Schuylkill	2 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2021 Every flash flood warning in 2021

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.