Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 21, NWS State College, PA

July 23, 20188 counties in Pennsylvania

NWS State College, PA issued this flash flood warning at Jul 23, 2018, 11:34 PM EDT for 8 counties in Pennsylvania. It was in force for 4 hr. 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 23, 2018, 11:34 PM EDT (03:34 UTC)
Expired
Jul 24, 2018, 3:30 AM EDT
In force
4 hr
Issued by
NWS State College, PA
Area
Storm-based polygon
Flood severity
None

Counties Centre County, PA, Clinton County, PA, Lycoming County, PA, Mifflin County, PA, Montour County, PA, Northumberland County, PA, Snyder County, PA, Union County, PA

The radar

The State College radar (KCCX), 88 km from the middle of the area, began a volume at 03:36 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 00:00Z, 3.6 hours before the alert went out and 225 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-pSkew-T log-p diagram, Washington/Dulle, VA at 00:00Z on 2018-07-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 791 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 00:00Z on 2018-07-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 115 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
791 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
722 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
115 m²/s²
0-3 km storm-relative helicity
141 m²/s²
Significant tornado parameter
0.4
Supercell composite
4.2

Open this sounding in Storm Lab

The text

As transmitted.

569 
WGUS51 KCTP 240334 CCA
FFWCTP
PAC027-035-081-087-093-097-109-119-240730-
/O.NEW.KCTP.FF.W.0021.180724T0334Z-180724T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service State College PA
1134 PM EDT MON JUL 23 2018

The National Weather Service in State College PA has issued a

* Flash Flood Warning for...
  Northumberland County in central Pennsylvania...
  Northeastern Mifflin County in central Pennsylvania...
  East central Centre County in central Pennsylvania...
  Snyder County in central Pennsylvania...
  Central Lycoming County in north central Pennsylvania...
  Northwestern Montour County in central Pennsylvania...
  Union County in central Pennsylvania...
  Eastern Clinton County in north central Pennsylvania...

* Until 330 AM EDT..

* At 1134 PM EDT, Doppler radar indicated heavy rain across the
  warned area. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Williamsport, Sunbury, Lock Haven, Milton, Lewisburg, Selinsgrove,
  Montoursville, Jersey Shore, Northumberland, Mifflinburg, Carroll,
  Woodward, Winfield, Muncy, Watsontown, Hughesville, Riverside,
  Trevorton, Shamokin Dam and Mill Hall.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4138 7670 4137 7669 4091 7665 4068 7666
      4064 7693 4065 7695 4064 7700 4068 7704
      4069 7711 4069 7729 4066 7739 4140 7758
      4140 7674

$$

Ross
1 follow-up statement
798 
WGUS71 KCTP 240556
FFSCTP

Flash Flood Statement
National Weather Service State College PA
156 AM EDT TUE JUL 24 2018

PAC027-035-081-087-093-097-109-119-240730-
/O.CON.KCTP.FF.W.0021.000000T0000Z-180724T0730Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Northumberland PA-Mifflin PA-Centre PA-Snyder PA-Lycoming PA-
Montour PA-Union PA-Clinton PA-
156 AM EDT TUE JUL 24 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 AM EDT FOR
NORTHUMBERLAND...NORTHEASTERN MIFFLIN...EAST CENTRAL CENTRE...
SNYDER...CENTRAL LYCOMING...NORTHWESTERN MONTOUR...UNION AND EASTERN
CLINTON COUNTIES...

At 155 AM EDT, Doppler radar indicated heavy rain continues across 
portions of the warned area.  Additional flash flooding is expected 
to occur. 

Some locations that may experience flooding include...
Williamsport, Sunbury, Lock Haven, Milton, Lewisburg, Selinsgrove,
Montoursville, Jersey Shore, Northumberland, Mifflinburg, Carroll,
Woodward, Winfield, Muncy, Watsontown, Hughesville, Riverside,
Trevorton, Shamokin Dam and Mill Hall.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 4138 7670 4137 7669 4091 7665 4068 7666
      4064 7693 4065 7695 4064 7700 4068 7704
      4069 7711 4069 7729 4066 7739 4140 7758
      4140 7674

$$

CR

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 23, 8:19 PM EDTAreal Flood AdvisoryCTPCumberland, Perry116 min
Jul 23, 8:57 PM EDTAreal Flood AdvisoryCTPAdams, York2 hr
Jul 23, 10:04 PM EDTFlash Flood WarningCTPAdams, Cumberland, Dauphin, Juniata, Lancaster, Northumberland and 2 more5 hr
Jul 23, 10:39 PM EDTAreal Flood AdvisoryCTPCentre, Clinton, Columbia, Juniata, Lycoming, Mifflin and 7 more3 hr
Jul 23, 11:30 PM EDTFlash Flood WarningCTPCentre, Clinton, Lycoming, Mifflin, Montour, Snyder and 1 more4 hr
Jul 24, 12:07 AM EDTFlash Flood WarningCTPLycoming, Tioga4 hr
Jul 24, 2:56 AM EDTAreal Flood WarningCTPAdams, Centre, Clinton, Cumberland, Dauphin, Juniata and 10 more6 hr
Jul 24, 3:43 AM EDTAreal Flood AdvisoryCTPDauphin, Lancaster, Lebanon, Schuylkill, York4 hr
Jul 24, 5:50 AM EDTAreal Flood AdvisoryCTPColumbia, Lycoming, Montour, Northumberland, Schuylkill, Sullivan3 hr
Jul 24, 8:35 AM EDTRiver Flood WarningCTPSnyder, Union58 hr
Jul 24, 8:35 AM EDTRiver Flood WarningCTPPerry23 hr
Jul 24, 8:35 AM EDTRiver Flood WarningCTPCumberland3 days
Jul 24, 9:06 AM EDTAreal Flood WarningCTPAdams, Centre, Clinton, Cumberland, Dauphin, Franklin and 11 more9 hr
Jul 24, 10:22 AM EDTRiver Flood WarningCTPHuntingdon58 hr
Jul 24, 10:54 AM EDTFlash Flood WarningCTPCumberland, Dauphin, Lancaster, York3 hr
Jul 24, 12:02 PM EDTAreal Flood AdvisoryCTPLancaster, Lebanon, York3 hr
Jul 24, 1:27 PM EDTAreal Flood AdvisoryCTPLebanon, Schuylkill3 hr
Jul 24, 1:35 PM EDTSpecial Weather StatementCTPSchuylkill40 min
Jul 24, 3:42 PM EDTAreal Flood AdvisoryCTPLancaster, Lebanon3 hr
Jul 24, 4:25 PM EDTAreal Flood AdvisoryCTPColumbia, Dauphin, Lebanon, Montour, Northumberland, Schuylkill2 hr
Jul 24, 5:20 PM EDTAreal Flood AdvisoryCTPColumbia, Lycoming, Montour, Sullivan, Tioga115 min
Jul 24, 5:45 PM EDTSpecial Weather StatementCTPFulton30 min
Jul 24, 5:58 PM EDTAreal Flood WarningCTPAdams, Centre, Clinton, Columbia, Cumberland, Dauphin and 17 more48 hr
Jul 24, 6:50 PM EDTSpecial Weather StatementCTPSnyder40 min

Nearby

Flash Flood Warnings in Pennsylvania, 2018Every flash flood 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.