Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 12, NWS State College, PA

July 17, 202113 counties in Pennsylvania

NWS State College, PA issued this flash flood warning at Jul 17, 2021, 5:56 PM EDT for 13 counties in Pennsylvania. It was in force for 3 hr. 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: Jul 17, 2021, 5:56 PM EDT (21:56 UTC)
Expired: Jul 17, 2021, 9:00 PM EDT
In force: 3 hr
Issued by: NWS State College, PA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Columbia County, PA, Cumberland County, PA, Dauphin County, PA, Juniata County, PA, Lebanon County, PA, Lycoming County, PA, Montour County, PA, Northumberland County, PA, Perry County, PA, Schuylkill County, PA, Snyder County, PA, Sullivan County, PA, Union County, PA

The radar

The State College radar (KCCX), 116 km from the middle of the area, began a volume at 21:58 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
Jul 17, 6:34 PM EDT	FLASH FLOOD	Millersburg, PA	WATER OVER MULTIPLE ROADS IN MILLERSBURG. PICTURES SENT VIA FACEBOOK.

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, 9.9 hours before the alert went out and 199 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: 538 J/kg
Mixed-layer CIN: -141 J/kg
Mixed-layer LCL: 1337 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 37 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

706 
WGUS51 KCTP 172156
FFWCTP
PAC037-041-043-067-075-081-093-097-099-107-109-113-119-180100-
/O.NEW.KCTP.FF.W.0012.210717T2156Z-210718T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service State College PA
556 PM EDT Sat Jul 17 2021

The National Weather Service in State College has issued a

* Flash Flood Warning for...
  Columbia County in central Pennsylvania...
  Northeastern Juniata County in central Pennsylvania...
  Montour County in central Pennsylvania...
  Northumberland County in central Pennsylvania...
  Western Schuylkill County in central Pennsylvania...
  Snyder County in central Pennsylvania...
  Union County in central Pennsylvania...
  Southeastern Lycoming County in north central Pennsylvania...
  Southwestern Sullivan County in north central Pennsylvania...
  Northern Cumberland County in south central Pennsylvania...
  Dauphin County in south central Pennsylvania...
  Lebanon County in south central Pennsylvania...
  Perry County in south central Pennsylvania...

* Until 900 PM EDT.

* At 556 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 may experience flash flooding include...
  Harrisburg, Williamsport, Lebanon, Carlisle, Lower Allen, 
  Bloomsburg, Hershey, Colonial Park, Berwick, Sunbury, Progress, 
  Mechanicsburg, Middletown, Camp Hill, Shamokin, Palmyra, New 
  Cumberland, Milton, Linglestown and Enola.

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 4146 7689 4139 7679 4129 7631 4121 7632
      4113 7628 4114 7623 4104 7623 4051 7632
      4050 7644 4043 7633 4041 7634 4019 7658
      4017 7675 4022 7690 4021 7690 4020 7693
      4019 7691 4016 7692 4011 7741 4015 7746

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

$$

CR

1 follow-up statement

223 
WGUS71 KCTP 180051
FFSCTP

Flash Flood Statement
National Weather Service State College PA
851 PM EDT Sat Jul 17 2021

PAC037-041-043-067-075-081-093-097-099-107-109-113-119-180101-
/O.EXP.KCTP.FF.W.0012.000000T0000Z-210718T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Columbia PA-Cumberland PA-Dauphin PA-Juniata PA-Lebanon PA-Lycoming
PA-Montour PA-Northumberland PA-Perry PA-Schuylkill PA-Snyder PA-
Sullivan PA-Union PA-
851 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 9 PM EDT THIS EVENING FOR 
COLUMBIA, NORTHEASTERN JUNIATA, MONTOUR, NORTHUMBERLAND, WESTERN 
SCHUYLKILL, SNYDER, UNION, SOUTHEASTERN LYCOMING, SOUTHWESTERN 
SULLIVAN, NORTHERN CUMBERLAND, DAUPHIN, LEBANON AND PERRY COUNTIES...

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 1000 PM EDT for a 
portion of central Pennsylvania.

LAT...LON 4146 7689 4139 7679 4129 7631 4121 7632
      4113 7628 4114 7623 4104 7623 4051 7632
      4050 7644 4043 7633 4041 7634 4019 7658
      4017 7675 4022 7690 4021 7690 4020 7693
      4019 7691 4016 7692 4011 7741 4015 7746

$$

Banghoff

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 16, 9:11 PM EDT	Special Weather Statement	CTP	Cumberland	34 min
Jul 16, 10:39 PM EDT	Areal Flood Advisory	CTP	Cumberland, Dauphin, Juniata, Northumberland, Perry, Snyder	2 hr
Jul 17, 4:33 AM EDT	Special Weather Statement	CTP	Warren	57 min
Jul 17, 6:36 AM EDT	Special Weather Statement	CTP	Warren	69 min
Jul 17, 7:46 AM EDT	Special Weather Statement	CTP	Elk, McKean	59 min
Jul 17, 10:23 AM EDT	Special Weather Statement	CTP	McKean	37 min
Jul 17, 12:01 PM EDT	Areal Flood Advisory	CTP	McKean	119 min
Jul 17, 12:35 PM EDT	Special Weather Statement	CTP	Potter	40 min
Jul 17, 12:55 PM EDT	Areal Flood Advisory	CTP	Warren	2 hr
Jul 17, 1:23 PM EDT	Special Weather Statement	CTP	Clinton	37 min
Jul 17, 1:33 PM EDT	Special Weather Statement	CTP	Lancaster	27 min
Jul 17, 1:48 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster, York	42 min
Jul 17, 1:55 PM EDT	Flash Flood Warning	CTP	Cameron, Elk, McKean, Potter, Warren	3 hr
Jul 17, 2:13 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster, Lebanon	47 min
Jul 17, 2:29 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	46 min
Jul 17, 2:46 PM EDT	Special Weather Statement	CTP	Cambria	29 min
Jul 17, 2:47 PM EDT	Areal Flood Advisory	CTP	Lancaster, Lebanon, Schuylkill, York	2 hr
Jul 17, 2:52 PM EDT	Severe Thunderstorm Warning	CTP	Schuylkill	38 min
Jul 17, 2:56 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster, York	34 min
Jul 17, 3:02 PM EDT	Severe Thunderstorm Warning	CTP	Lebanon, Schuylkill	43 min
Jul 17, 3:04 PM EDT	Severe Thunderstorm Warning	CTP	Cambria, Clearfield, Somerset	56 min
Jul 17, 3:06 PM EDT	Special Weather Statement	CTP	Blair	24 min
Jul 17, 3:14 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	61 min
Jul 17, 3:17 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Lycoming, Tioga	3 hr
Jul 17, 3:35 PM EDT	Special Weather Statement	CTP	Centre	25 min
Jul 17, 3:42 PM EDT	Special Weather Statement	CTP	York	33 min
Jul 17, 3:45 PM EDT	Special Weather Statement	CTP	Huntingdon	30 min
Jul 17, 3:48 PM EDT	Special Weather Statement	CTP	Lancaster	27 min
Jul 17, 3:52 PM EDT	Severe Thunderstorm Warning	CTP	Centre, Clearfield	23 min
Jul 17, 4:03 PM EDT	Special Weather Statement	CTP	Dauphin	27 min
Jul 17, 4:05 PM EDT	Severe Thunderstorm Warning	CTP	Centre, Huntingdon, Juniata, Mifflin	55 min
Jul 17, 4:07 PM EDT	Areal Flood Advisory	CTP	Adams, Cumberland, Dauphin, Lancaster, Lebanon, York	2 hr
Jul 17, 4:14 PM EDT	Special Weather Statement	CTP	Dauphin	31 min
Jul 17, 4:14 PM EDT	Special Weather Statement	CTP	Tioga	46 min
Jul 17, 4:23 PM EDT	Special Weather Statement	CTP	Clinton	37 min
Jul 17, 4:24 PM EDT	Special Weather Statement	CTP	Dauphin	36 min
Jul 17, 4:32 PM EDT	Special Weather Statement	CTP	Lycoming	28 min
Jul 17, 4:34 PM EDT	Special Weather Statement	CTP	Centre	26 min
Jul 17, 4:38 PM EDT	Areal Flood Advisory	CTP	Clinton, Lycoming	2 hr
Jul 17, 4:44 PM EDT	Areal Flood Advisory	CTP	Bedford, Cumberland, Franklin, Fulton, Huntingdon, Juniata and 3 more	2 hr
Jul 17, 4:45 PM EDT	Special Weather Statement	CTP	Dauphin	30 min
Jul 17, 4:47 PM EDT	Special Weather Statement	CTP	Tioga	28 min
Jul 17, 4:50 PM EDT	Special Weather Statement	CTP	Somerset	25 min
Jul 17, 4:50 PM EDT	Severe Thunderstorm Warning	CTP	Juniata, Mifflin, Northumberland, Snyder, Union	55 min
Jul 17, 4:53 PM EDT	Areal Flood Advisory	CTP	Cameron, Elk, McKean, Potter, Warren	66 min
Jul 17, 4:56 PM EDT	Areal Flood Advisory	CTP	Columbia, Dauphin, Lycoming, Montour, Northumberland, Schuylkill and 3 more	61 min
Jul 17, 4:58 PM EDT	Special Weather Statement	CTP	Clinton	32 min
Jul 17, 5:02 PM EDT	Severe Thunderstorm Warning	CTP	Clinton, Lycoming	43 min
Jul 17, 5:08 PM EDT	Special Weather Statement	CTP	Franklin	37 min
Jul 17, 5:14 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Lycoming, Sullivan	3 hr
Jul 17, 5:16 PM EDT	Special Weather Statement	CTP	Dauphin	29 min
Jul 17, 5:20 PM EDT	Areal Flood Advisory	CTP	Cumberland, Dauphin, Juniata, Lebanon, Perry	2 hr
Jul 17, 5:27 PM EDT	Special Weather Statement	CTP	Sullivan	33 min
Jul 17, 5:30 PM EDT	Special Weather Statement	CTP	Franklin	30 min
Jul 17, 5:42 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Adams, Cumberland, Franklin, Fulton, Huntingdon, Perry	111 min
Jul 17, 5:44 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Cumberland, Dauphin, Juniata, Lycoming, Montour and 6 more	61 min
Jul 17, 6:09 PM EDT	Severe Thunderstorm Warning	CTP	Adams, Cumberland, Dauphin, Franklin, York	36 min
Jul 17, 6:22 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Lycoming, Sullivan	28 min
Jul 17, 6:44 PM EDT	Severe Thunderstorm Warning	CTP	Adams, Dauphin, Lancaster, Lebanon, York	46 min
Jul 17, 6:57 PM EDT	Special Weather Statement	CTP	Schuylkill	33 min
Jul 17, 7:07 PM EDT	Areal Flood Advisory	CTP	Adams, York	2 hr
Jul 17, 7:34 PM EDT	Severe Thunderstorm Warning	CTP	Adams, York	56 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.