Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 14, NWS State College, PA

August 11, 2021Cumberland County, Dauphin County, York County, Pennsylvania

NWS State College, PA issued this flash flood warning at Aug 11, 2021, 5:00 PM EDT for Cumberland County, Dauphin County, York County, Pennsylvania. It was in force for 85 min. 2 reports 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 11, 2021, 5:00 PM EDT (21:00 UTC)
Expired: Aug 11, 2021, 6:25 PM EDT
In force: 85 min
Issued by: NWS State College, PA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Cumberland County, PA, Dauphin County, PA, York County, PA

The radar

The State College radar (KCCX), 118 km from the middle of the area, began a volume at 21:03 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 11, 5:31 PM EDT	FLASH FLOOD	1 Ese Harrisburg, PA	VEHICLES STRANDED IN WATER.
Aug 11, 5:40 PM EDT	FLASH FLOOD	1 Se Harrisburg, PA	REPORT VIA TWITTER OF VEHICLES SUBMERGED IN WATER ON MARKET STREET.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 9.0 hours before the alert went out and 155 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: 553 J/kg
Mixed-layer CIN: -190 J/kg
Mixed-layer LCL: 1301 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 77 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

950 
WGUS51 KCTP 112100
FFWCTP
PAC041-043-133-112300-
/O.NEW.KCTP.FF.W.0014.210811T2100Z-210811T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service State College PA
500 PM EDT Wed Aug 11 2021

The National Weather Service in State College has issued a

* Flash Flood Warning for...
  Northeastern Cumberland County in south central Pennsylvania...
  Southern Dauphin County in south central Pennsylvania...
  North Central York County in south central Pennsylvania...

* Until 700 PM EDT.

* At 500 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Additional rainfall amounts of 
  1 to 2 inches are possible in the warned area. 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...
  Harrisburg, Lower Allen, Hershey, Colonial Park, Progress, 
  Mechanicsburg, Middletown, Camp Hill, New Cumberland, Linglestown, 
  Enola, Steelton, Lemoyne, Hummelstown, Paxtonia, Rutherford, 
  Skyline View, Lawnton, Valley Green and Wormleysburg.

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 4028 7701 4032 7694 4032 7693 4033 7691
      4033 7692 4035 7689 4039 7675 4033 7666
      4026 7661 4011 7684 4024 7702 4024 7703

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

$$

CR

2 follow-up statements

967 
WGUS71 KCTP 112155
FFSCTP

Flash Flood Statement
National Weather Service State College PA
555 PM EDT Wed Aug 11 2021

PAC041-043-133-112300-
/O.CON.KCTP.FF.W.0014.000000T0000Z-210811T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cumberland PA-Dauphin PA-York PA-
555 PM EDT Wed Aug 11 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM EDT THIS EVENING 
FOR NORTHEASTERN CUMBERLAND, SOUTHERN DAUPHIN AND NORTH CENTRAL YORK 
COUNTIES...

At 555 PM EDT, Heavy rains are ending across the warned area, 
however flash flooding will continue for the next hour.

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...
  Harrisburg, Lower Allen, Hershey, Colonial Park, Progress, 
  Mechanicsburg, Middletown, Camp Hill, New Cumberland, Linglestown, 
  Enola, Steelton, Lemoyne, Hummelstown, Paxtonia, Rutherford, 
  Skyline View, Lawnton, Valley Green and Wormleysburg.

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 4028 7701 4032 7694 4032 7693 4033 7691
      4033 7692 4035 7689 4039 7675 4033 7666
      4026 7661 4011 7684 4024 7702 4024 7703

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

$$

CR

674 
WGUS71 KCTP 112225
FFSCTP

Flash Flood Statement
National Weather Service State College PA
625 PM EDT Wed Aug 11 2021

PAC041-043-133-112235-
/O.CAN.KCTP.FF.W.0014.000000T0000Z-210811T2300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Cumberland PA-Dauphin PA-York PA-
625 PM EDT Wed Aug 11 2021

...FLASH FLOOD WARNING FOR NORTHEASTERN CUMBERLAND, SOUTHERN DAUPHIN 
AND NORTH CENTRAL YORK COUNTIES HAS BEEN REPLACED WITH A FLOOD 
ADVISORY...

LAT...LON 4028 7701 4032 7694 4032 7693 4033 7691
      4033 7692 4035 7689 4039 7675 4033 7666
      4026 7661 4011 7684 4024 7702 4024 7703

$$

CR

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 12:18 AM EDT	Special Weather Statement	CTP	Union	27 min
Aug 11, 3:38 AM EDT	Excessive Heat Warning	CTP	Adams, Columbia, Cumberland, Dauphin, Franklin, Juniata and 10 more	39 hr
Aug 11, 5:03 AM EDT	Special Weather Statement	CTP	Warren	27 min
Aug 11, 6:40 AM EDT	Special Weather Statement	CTP	McKean	50 min
Aug 11, 2:11 PM EDT	Special Weather Statement	CTP	Cambria	49 min
Aug 11, 2:32 PM EDT	Severe Thunderstorm Warning	CTP	Dauphin, Lancaster, Lebanon, York	58 min
Aug 11, 2:59 PM EDT	Special Weather Statement	CTP	Somerset	61 min
Aug 11, 3:02 PM EDT	Special Weather Statement	CTP	Blair	28 min
Aug 11, 3:13 PM EDT	Severe Thunderstorm Warning	CTP	Bedford, Blair, Huntingdon	46 min
Aug 11, 3:28 PM EDT	Severe Thunderstorm Warning	CTP	Centre, Huntingdon, Mifflin	62 min
Aug 11, 3:34 PM EDT	Severe Thunderstorm Warning	CTP	Mifflin	41 min
Aug 11, 3:35 PM EDT	Special Weather Statement	CTP	Huntingdon	25 min
Aug 11, 3:49 PM EDT	Special Weather Statement	CTP	Juniata	26 min
Aug 11, 3:55 PM EDT	Special Weather Statement	CTP	Dauphin	35 min
Aug 11, 4:07 PM EDT	Special Weather Statement	CTP	York	38 min
Aug 11, 4:08 PM EDT	Special Weather Statement	CTP	Franklin	37 min
Aug 11, 4:13 PM EDT	Special Weather Statement	CTP	Juniata, Perry, Snyder, Union	32 min
Aug 11, 4:23 PM EDT	Severe Thunderstorm Warning	CTP	Centre, Snyder, Union	59 min
Aug 11, 4:37 PM EDT	Severe Thunderstorm Warning	CTP	Dauphin	53 min
Aug 11, 4:42 PM EDT	Special Weather Statement	CTP	York	33 min
Aug 11, 4:43 PM EDT	Special Weather Statement	CTP	Cumberland	32 min
Aug 11, 4:47 PM EDT	Severe Thunderstorm Warning	CTP	Dauphin, Juniata, Northumberland, Perry, Snyder	53 min
Aug 11, 4:52 PM EDT	Areal Flood Advisory	CTP	Dauphin	2 hr
Aug 11, 4:54 PM EDT	Special Weather Statement	CTP	Lebanon	36 min
Aug 11, 5:00 PM EDT	Special Weather Statement	CTP	York	30 min
Aug 11, 5:08 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Montour, Northumberland	52 min
Aug 11, 5:14 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	46 min
Aug 11, 5:35 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Northumberland	48 min
Aug 11, 5:44 PM EDT	Areal Flood Advisory	CTP	Lancaster, Lebanon	2 hr
Aug 11, 5:47 PM EDT	Special Weather Statement	CTP	Lancaster, York	58 min
Aug 11, 5:54 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster, York	51 min
Aug 11, 5:58 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	47 min
Aug 11, 6:25 PM EDT	Areal Flood Advisory	CTP	Cumberland, Dauphin, York	95 min
Aug 11, 7:14 PM EDT	Special Weather Statement	CTP	Warren	31 min

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.