Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 7, NWS Philadelphia/Mount Holly

May 27, 2018Bucks County, Pennsylvania; Hunterdon County, New Jersey

NWS Philadelphia/Mount Holly issued this flash flood warning at May 27, 2018, 6:33 AM EDT for Bucks County, Pennsylvania; Hunterdon County, New Jersey. It was in force for 4 hr. 4 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: May 27, 2018, 6:33 AM EDT (10:33 UTC)
Expired: May 27, 2018, 10:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Hunterdon County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 67 km from the middle of the area, began a volume at 10:35 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
May 27, 6:40 AM EDT	HEAVY RAIN 3.63	1 Sw Solebury Twp, PA	3.5 INCHES OF RAINFALL IN THE PAST HOUR
May 27, 6:54 AM EDT	HEAVY RAIN 3.75	Doylestown Airport, PA	RAINFALL OCCURRED OVER AN 80 MIN-PERIOD
May 27, 7:00 AM EDT	FLASH FLOOD	Doylestown, PA	ROADWAY FLOODING THROUGHOUT TOWN.
May 27, 7:30 AM EDT	FLOOD	Doylestown, PA	SOME FLOODED ROADWAYS THROUGHOUT TOWN.

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

The nearest sounding before it

Brookhaven, NY (KOKX), launched 00:00Z, 10.6 hours before the alert went out and 192 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: 861 J/kg
Mixed-layer CIN: -92 J/kg
Mixed-layer LCL: 1209 m above ground
0-6 km bulk shear: 35 kt
0-1 km storm-relative helicity: 83 m²/s²
0-3 km storm-relative helicity: 84 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.2

Open this sounding in Storm Lab

The text

As transmitted.

773 
WGUS51 KPHI 271033
FFWPHI
NJC019-PAC017-271430-
/O.NEW.KPHI.FF.W.0007.180527T1033Z-180527T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
633 AM EDT SUN MAY 27 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  South central Hunterdon County in northwestern New Jersey...
  Central Bucks County in southeastern Pennsylvania...

* Until 1030 AM EDT.

* At 632 AM EDT, Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Up to 
  three inches of rain have already fallen in the last hour. Flash 
  flooding is expected to begin shortly in the areas of heaviest 
  rain.

* Some locations that could experience flooding include...
  Doylestown, Byram, Chalfont, Tinicum, New Hope, Dublin, Ivyland,
  Stockton, Richboro, Sergeantsville, Pipersville, Gardenville,
  Lumberville, Lambertville, New Britain, Newtown Grant and Brittany
  Farms-Highlands.

Additional rainfall amounts of one to two inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report flooding to your local law enforcement agency when you
can do so safely.

A Flash Flood Warning means that flooding is imminent or occurring.
If you are in the warned area move to higher ground immediately.
Residents living along streams and creeks should take immediate
precautions to protect life and property.

&&

LAT...LON 4034 7489 4034 7494 4031 7490 4024 7492
      4020 7505 4024 7518 4025 7520 4031 7523
      4040 7520 4046 7510 4047 7485

$$

JRK

1 follow-up statement

966 
WGUS71 KPHI 271429
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1029 AM EDT SUN MAY 27 2018

NJC019-PAC017-271438-
/O.EXP.KPHI.FF.W.0007.000000T0000Z-180527T1430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Hunterdon NJ-Bucks PA-
1029 AM EDT SUN MAY 27 2018

...THE FLASH FLOOD WARNING FOR SOUTH CENTRAL HUNTERDON AND CENTRAL
BUCKS COUNTIES WILL EXPIRE AT 1030 AM EDT...

The Flash Flood Warning has been converted to a Flood Warning. 
Runoff and flooding will continue into the afternoon. A widespread 
one to three inches fell in a short period of time earlier this 
morning. 

LAT...LON 4034 7489 4034 7494 4031 7490 4024 7492
      4020 7505 4024 7518 4025 7520 4031 7523
      4040 7520 4046 7510 4047 7485

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
May 26, 11:38 PM EDT	Flash Flood Watch	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	23 hr
May 27, 7:30 AM EDT	Flash Flood Warning	PHI	Bucks	4 hr
May 27, 8:01 AM EDT	Flash Flood Warning	PHI	Bucks, Chester, Montgomery	4 hr
May 27, 9:17 AM EDT	Areal Flood Advisory	PHI	Bucks	3 hr
May 27, 9:21 AM EDT	River Flood Warning	PHI	Bucks	12 hr
May 27, 9:22 AM EDT	Areal Flood Advisory	PHI	Philadelphia	2 hr
May 27, 9:39 AM EDT	Areal Flood Advisory	PHI	Chester, Delaware, Montgomery	2 hr
May 27, 10:27 AM EDT	Areal Flood Warning	PHI	Bucks	8 hr
May 27, 11:18 AM EDT	Areal Flood Warning	PHI	Bucks	7 hr
May 27, 3:22 PM EDT	Coastal Flood Advisory	PHI	Bucks, Delaware, Philadelphia	12 hr
May 27, 6:07 PM EDT	Areal Flood Warning	PHI	Bucks	4 hr
May 27, 1:27 AM EDT	Special Marine Warning	PHI		2 hr
May 27, 1:46 AM EDT	Special Marine Warning	PHI		89 min
May 27, 1:58 AM EDT	Areal Flood Advisory	PHI	Monmouth	4 hr
May 27, 2:13 AM EDT	Areal Flood Advisory	PHI	Morris, Warren	4 hr
May 27, 4:13 AM EDT	Areal Flood Advisory	PHI	Middlesex, Somerset	4 hr
May 27, 4:28 AM EDT	Flash Flood Warning	PHI	Monmouth	4 hr
May 27, 4:39 AM EDT	Flash Flood Warning	PHI	Middlesex, Somerset	4 hr
May 27, 5:27 AM EDT	Areal Flood Advisory	PHI	Hunterdon	4 hr
May 27, 5:35 AM EDT	Areal Flood Advisory	PHI	Mercer, Middlesex, Monmouth	4 hr
May 27, 5:43 AM EDT	Flash Flood Warning	PHI	Monmouth	4 hr
May 27, 6:12 AM EDT	Flash Flood Warning	PHI	Mercer, Middlesex, Somerset	4 hr
May 27, 8:25 AM EDT	Areal Flood Warning	PHI	Monmouth	7 hr
May 27, 8:40 AM EDT	Areal Flood Warning	PHI	Middlesex, Somerset	4 hr
May 27, 9:05 AM EDT	River Flood Warning	PHI	Mercer	13 hr
May 27, 10:02 AM EDT	Areal Flood Warning	PHI	Monmouth	6 hr
May 27, 10:19 AM EDT	Areal Flood Warning	PHI	Hunterdon, Mercer, Middlesex, Somerset	8 hr
May 27, 3:10 PM EDT	River Flood Warning	PHI	Somerset	46 hr
May 27, 3:44 PM EDT	Areal Flood Warning	PHI	Monmouth	16 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2018 Flash Flood Warnings in New Jersey, 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.