Alert archive / Pennsylvania / Flash Flood Warnings in 2021

Flash Flood Warning 11, NWS State College, PA

July 17, 20216 counties in Pennsylvania

NWS State College, PA issued this flash flood warning at Jul 17, 2021, 5:42 PM EDT for 6 counties in Pennsylvania. It was in force for 111 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: Jul 17, 2021, 5:42 PM EDT (21:42 UTC)
Expired: Jul 17, 2021, 7:33 PM EDT
In force: 111 min
Issued by: NWS State College, PA
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Adams County, PA, Cumberland County, PA, Franklin County, PA, Fulton County, PA, Huntingdon County, PA, Perry County, PA

The radar

The State College radar (KCCX), 83 km from the middle of the area, began a volume at 21:41 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, 9.7 hours before the alert went out and 143 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.

142 
WGUS51 KCTP 172142
FFWCTP
PAC001-041-055-057-061-099-172345-
/O.NEW.KCTP.FF.W.0011.210717T2142Z-210717T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in State College has issued a

* Flash Flood Warning for...
  Southeastern Huntingdon County in central Pennsylvania...
  Western Adams County in south central Pennsylvania...
  Western Cumberland County in south central Pennsylvania...
  Franklin County in south central Pennsylvania...
  Eastern Fulton County in south central Pennsylvania...
  Southwestern Perry County in south central Pennsylvania...

* Until 745 PM EDT.

* At 542 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...
  Chambersburg, Waynesboro, Shippensburg, Greencastle, Guilford, St. 
  Thomas, Carroll Valley, Fayetteville, Wayne Heights, Mount Union, 
  Mont Alto, Mercersburg, Scotland, Newville, McConnellsburg, 
  Harrisonville, Rouzerville, Marion, Fort Loudon and Big Cove 
  Tannery.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 4017 7805 4041 7791 4040 7791 4036 7782
      4038 7775 4026 7770 4038 7753 4040 7754
      4049 7730 4025 7734 3976 7729 3972 7784
      3978 7821

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

$$

CR

1 follow-up statement

679 
WGUS71 KCTP 172333
FFSCTP

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

PAC001-041-055-057-061-099-172343-
/O.CAN.KCTP.FF.W.0011.000000T0000Z-210717T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Adams PA-Cumberland PA-Franklin PA-Fulton PA-Huntingdon PA-Perry PA-
733 PM EDT Sat Jul 17 2021

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHEASTERN HUNTINGDON, 
WESTERN ADAMS, WESTERN CUMBERLAND, FRANKLIN, EASTERN FULTON AND 
SOUTHWESTERN PERRY COUNTIES...

Flood waters have receded. 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 4017 7805 4040 7791 4036 7782 4038 7775
      4026 7770 4038 7753 4040 7754 4049 7730
      4025 7734 3976 7729 3972 7785 3978 7821

$$

CR

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, 5:44 PM EDT	Severe Thunderstorm Warning	CTP	Columbia, Cumberland, Dauphin, Juniata, Lycoming, Montour and 6 more	61 min
Jul 17, 5:56 PM EDT	Flash Flood Warning Considerable damage threat	CTP	Columbia, Cumberland, Dauphin, Juniata, Lebanon, Lycoming and 7 more	3 hr
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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.