Alert archive / Pennsylvania / Flash Flood Warnings in 2018

Flash Flood Warning 8, NWS Philadelphia/Mount Holly

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

NWS Philadelphia/Mount Holly issued this flash flood warning at May 27, 2018, 7:30 AM EDT for Bucks County, Pennsylvania; Mercer County, New Jersey. It was in force for 4 hr. 7 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, 7:30 AM EDT (11:30 UTC)
Expired: May 27, 2018, 11:30 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Mercer County, NJ, Bucks County, PA

The radar

The Philadelphia radar (KDIX), 45 km from the middle of the area, began a volume at 11:32 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, 8:00 AM EDT	HEAVY RAIN 3.3	Langhorne, PA	BETWEEN 5:00 AND 8:00 AM. ABOUT 2.1 INCHES BETWEEN 7:00 AND 8:00 AM.
May 27, 8:00 AM EDT	HEAVY RAIN 5.54	2 N Mercerville-Hamilto, NJ	RAINFALL IN THE PAST THREE HOURS
May 27, 8:00 AM EDT	HEAVY RAIN 6	2 N Mercerville-Hamilto, NJ
May 27, 8:04 AM EDT	FLASH FLOOD	Trenton, NJ	ONGOING WATER RESCUES IN MERCER CO. FURTHER INFORMATION NOT AVAILABLE AT THIS TIME. MORE INFO WILL BE PROVIDED LATER.
May 27, 8:29 AM EDT	HEAVY RAIN 2.18	Ewing, NJ
May 27, 8:29 AM EDT	HEAVY RAIN 3.69	Mercerville, NJ
May 27, 9:54 AM EDT	FLOOD	Robbinsville, NJ	FLOODING ON US 130 SB AT CHURCH RD. RIGHT LANE CLOSED.

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, 11.5 hours before the alert went out and 179 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.

413 
WGUS51 KPHI 271130
FFWPHI
NJC021-PAC017-271530-
/O.NEW.KPHI.FF.W.0008.180527T1130Z-180527T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southern Mercer County in central New Jersey...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 1130 AM EDT.

* At 729 AM EDT, Doppler radar and automated rain gauges indicated 
  thunderstorms that are producing heavy rain continue to build to 
  the south. Two to three inches of rain have already fallen in the 
  past 45 minutes. Flash flooding is expected to begin shortly in 
  the areas of heaviest rain.

* Some locations that could experience flooding include...
  Trenton, Ewing, Yardley, Newtown, Tullytown, Langhorne, Washington
  Crossing, Feasterville-Trevose, Windsor, Feasterville, Woodside,
  White Horse, Mercerville-Hamilton Square, Langhorn, Levittown,
  Richboro, Morrisville, Penndel, Langhorne Manor and Hulmeville.

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 4023 7451 4018 7469 4019 7470 4017 7471
      4012 7497 4017 7508 4020 7507 4024 7495
      4031 7490 4029 7486 4027 7470

$$

JRK

1 follow-up statement

587 
WGUS71 KPHI 271523
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1123 AM EDT SUN MAY 27 2018

NJC021-PAC017-271532-
/O.EXP.KPHI.FF.W.0008.000000T0000Z-180527T1530Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mercer NJ-Bucks PA-
1123 AM EDT SUN MAY 27 2018

...THE FLASH FLOOD WARNING FOR SOUTHERN MERCER AND SOUTHEASTERN BUCKS
COUNTIES WILL EXPIRE AT 1130 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 4023 7451 4018 7469 4019 7470 4017 7471
      4012 7497 4017 7508 4020 7507 4024 7495
      4031 7490 4029 7486 4027 7470

$$

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, 6:33 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.