Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 61, NWS Philadelphia/Mount Holly

August 11, 2018Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 11, 2018, 2:14 PM EDT for Bucks County, Pennsylvania. It was in force for 3 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: Aug 11, 2018, 2:14 PM EDT (18:14 UTC)
Expired: Aug 11, 2018, 5:15 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Bucks County, PA

The radar

The Philadelphia radar (KDIX), 60 km from the middle of the area, began a volume at 18:18 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

Brookhaven, NY (KOKX), launched 12:00Z, 6.2 hours before the alert went out and 188 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: 840 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 590 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 31 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 1.9

Open this sounding in Storm Lab

The text

As transmitted.

451 
WGUS51 KPHI 111814
FFWPHI
PAC017-112115-
/O.NEW.KPHI.FF.W.0061.180811T1814Z-180811T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
214 PM EDT SAT AUG 11 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Central Bucks County in southeastern Pennsylvania...

* Until 515 PM EDT.

* At 212 PM EDT, Doppler radar indicated thunderstorms producing 
  heavy rain in central Montgomery County moving east-northeast 
  toward central Bucks County. Rainfall rates over 2 inches per hour 
  have been reported in some of these storms, so flash flooding can 
  be expected in central Bucks County this afternoon.
 
* Some locations that could experience flooding include...
  Doylestown, Byram, Chalfont, New Hope, Yardley, Newtown, Dublin, 
  Tullytown, Langhorne, Ivyland, Stockton, Washington Crossing, 
  Feasterville-Trevose, Feasterville, Woodside, Richboro and 
  Langhorne.

LAT...LON 4009 7493 4032 7532 4046 7507 4040 7504
      4041 7499 4040 7496 4033 7494 4030 7487
      4025 7484 4023 7480 4018 7475

$$

jjm

1 follow-up statement

054 
WGUS71 KPHI 112109
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
509 PM EDT SAT AUG 11 2018

PAC017-112117-
/O.EXP.KPHI.FF.W.0061.000000T0000Z-180811T2115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
509 PM EDT SAT AUG 11 2018

...THE FLASH FLOOD WARNING FOR CENTRAL BUCKS COUNTY WILL EXPIRE AT
515 PM EDT...

While residual flooding is still possible due to earlier rain, flash 
flooding is no longer expected to pose a threat. The flash flood 
warning will therefore be allowed to expire.

LAT...LON 4009 7493 4032 7532 4046 7507 4040 7504
      4041 7499 4040 7496 4033 7494 4030 7487
      4025 7484 4023 7480 4018 7475

$$

jjm

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 11, 2:25 AM EDT	Special Weather Statement	PHI	Berks	65 min
Aug 11, 3:24 AM EDT	Flash Flood Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	20 hr
Aug 11, 3:26 AM EDT	Special Weather Statement	PHI	Berks	64 min
Aug 11, 4:17 AM EDT	Areal Flood Advisory	PHI	Berks	4 hr
Aug 11, 4:26 AM EDT	Coastal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	24 hr
Aug 11, 5:19 AM EDT	Flash Flood Warning	PHI	Berks	3 hr
Aug 11, 5:27 AM EDT	Areal Flood Advisory	PHI	Northampton	4 hr
Aug 11, 6:06 AM EDT	Areal Flood Advisory	PHI	Bucks, Northampton	6 hr
Aug 11, 6:31 AM EDT	Areal Flood Advisory	PHI	Bucks	7 hr
Aug 11, 12:16 PM EDT	Special Weather Statement	PHI	Chester	29 min
Aug 11, 12:48 PM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Aug 11, 1:20 PM EDT	Areal Flood Advisory	PHI	Chester, Montgomery	3 hr
Aug 11, 1:33 PM EDT	Flash Flood Warning	PHI	Chester, Montgomery	4 hr
Aug 11, 1:40 PM EDT	Flash Flood Warning	PHI	Chester	4 hr
Aug 11, 1:48 PM EDT	Flash Flood Warning	PHI	Delaware, Philadelphia	4 hr
Aug 11, 1:51 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	39 min
Aug 11, 2:00 PM EDT	Flash Flood Warning	PHI	Bucks, Lehigh, Northampton	9 hr
Aug 11, 2:26 PM EDT	Special Weather Statement	PHI	Bucks, Philadelphia	34 min
Aug 11, 2:42 PM EDT	Special Weather Statement	PHI	Bucks	33 min
Aug 11, 3:06 PM EDT	Flash Flood Warning	PHI	Northampton	4 hr
Aug 11, 3:50 PM EDT	Areal Flood Advisory	PHI	Berks, Montgomery	115 min
Aug 11, 4:19 PM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Aug 11, 4:19 PM EDT	Severe Thunderstorm Warning	PHI	Chester	29 min
Aug 11, 4:47 PM EDT	Special Weather Statement	PHI	Montgomery	28 min
Aug 11, 4:52 PM EDT	Areal Flood Advisory	PHI	Carbon, Lehigh	2 hr
Aug 11, 5:36 PM EDT	Areal Flood Warning	PHI	Bucks	4 hr
Aug 11, 5:58 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery, Philadelphia	5 hr
Aug 11, 6:13 PM EDT	Special Weather Statement	PHI	Chester	32 min

Nearby

Flash Flood Warnings in Pennsylvania, 2018 Every 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.