Alert archive / Pennsylvania / Flash Flood Warnings in 2017

Flash Flood Warning 24, NWS Philadelphia/Mount Holly

July 23, 2017Chester County, Delaware County, Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at Jul 23, 2017, 6:53 PM EDT for Chester County, Delaware County, Pennsylvania; New Castle County, Delaware. It was in force for 14 hr. 25 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: Jul 23, 2017, 6:53 PM EDT (22:53 UTC)
Expired: Jul 24, 2017, 9:00 AM EDT
In force: 14 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties New Castle County, DE, Chester County, PA, Delaware County, PA

The radar

The Philadelphia radar (KDIX), 117 km from the middle of the area, began a volume at 22:54 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
Jul 23, 7:00 PM EDT	FLOOD	Wawaset Park, DE	VEHICLE TEMPORARILY STRANDED IN HIGH WATER ON PENNSYLVANIA AVE AND UNION ST
Jul 23, 7:43 PM EDT	FLASH FLOOD	Henry Clay, DE	ROUTE 141 NORTHBOUND WAS CLOSED AT BARLEY MILL ROAD DUE TO FLASH FLOODING.
Jul 23, 8:00 PM EDT	FLASH FLOOD	Wooddale, DE	3 PEOPLE WERE TRAPPED IN A VEHICLE AND RESCUED ALONG BARLEY MILLS ROAD NEAR HOOPS RESERVOIR.
Jul 23, 8:30 PM EDT	FLASH FLOOD	Chatwood, PA	VEHICLE STUCK IN FLOODWATERS AT GAY AND MONTGOMERY STREET.
Jul 23, 8:30 PM EDT	HEAVY RAIN 3.94	Chadds Ford, PA	A TOTAL OF 3.94 INCHES OF RAIN FELL IN CHADDS FORD WITH 2.01 INCHES FALLING IN ONE HOUR.
Jul 23, 8:35 PM EDT	HEAVY RAIN 3.31	Nanticoke Farms, DE	CWOP WEATHER STATION 24 HOUR TOTAL.
Jul 23, 8:42 PM EDT	FLASH FLOOD	Wooddale, DE	RED CLAY CREEK EXCEEDS FS TIME EST. 4 FT RISE 70MIN.
Jul 23, 8:42 PM EDT	HEAVY RAIN 4.19	1 Wsw Kentmere, DE
Jul 23, 9:00 PM EDT	FLASH FLOOD	1 W Rosedale, PA	A VEHICLE WAS STUCK IN HIGH WATER NEAR BAYARD ROAD AND ROSEDALE ROAD IN KENNETT TOWNSHIP.
Jul 23, 9:10 PM EDT	FLASH FLOOD	1 E Guyencourt, DE	THOMPSON BRIDGE ROAD WAS CLOSED DUE TO FLOODING.
Jul 23, 9:15 PM EDT	FLASH FLOOD	1 Ssw Fairthorne, DE	A SWIFTWATER RECSUE TOOK PLACE ON KENNETH PIKE. THE EVENT TIME WAS ESTIMATED.
Jul 23, 9:15 PM EDT	FLASH FLOOD	Woodland Park, DE	A SWIFTWATER RESCUE TOOK PLACE ON FAULKIN ROAD. THE EVENT TIME IS ESTIMATED.
Jul 23, 9:17 PM EDT	FLASH FLOOD	1 Sw Mendenhall, PA	BURROWS RUN ROAD IN KENNETT TOWNSHIP WAS REPORTED FLOODED.
Jul 23, 9:41 PM EDT	FLASH FLOOD	Montchanin, DE	MULTIPLE ROADS ARE FLOODED..
Jul 23, 10:04 PM EDT	HEAVY RAIN 1.82	Upper Uwchlan Twp, PA	DAILY RAINFALL TODAY SO FAR.
Jul 23, 10:11 PM EDT	HEAVY RAIN 2.2	Centerville, DE
Jul 23, 10:20 PM EDT	HEAVY RAIN 2.01	Arbor Pointe Apartments, DE	MESONET STATION MEASURED 2.01 INCHES OF RAIN IN THE LAST 24 HOURS WITH 1.81 INCH IN 3 HOURS.
Jul 23, 10:40 PM EDT	FLASH FLOOD	Stanton Estates, DE	RED CLAY CREEK STANTON 9.5 FT RISE 3.5HRS
Jul 23, 10:40 PM EDT	FLASH FLOOD	Stanton Estates, DE	RED CLAY CREEK STANTON 9.5 FT RISE 3.5HRS. EXCEED FS 1040P
Jul 23, 11:10 PM EDT	HEAVY RAIN 5.95	Winterthur, DE	DEOS MESONET STATION IN GREENVILLE MEASURED A TOTAL OF 5.95 INCHES TODAY. A TOTAL OF 0.46 INCHES FELL IN 5 MINUTES ENDING AT 825 PM WITH 0.82 INCHES IN 10 MINUTES ENDING AT 830 PM.
Jul 23, 11:12 PM EDT	FLASH FLOOD	Ashland, DE	CREEK ROAD WAS CLOSED BETWEEN PYLES FORD ROAD AND WAY ROAD.
Jul 23, 11:22 PM EDT	FLASH FLOOD	Wooddale, DE	WOODALE COVERED BRIDGE WAS CLOSED ON FOXHILL LANE DUE TO HIGH WATER.
Jul 23, 11:59 PM EDT	HEAVY RAIN 2.3	Blue Ball, DE	WILMINGTON PORTER RESERVOIR 24 HOUR RAIN TOTAL.
Jul 24, 4:00 AM EDT	HEAVY RAIN 7.44	Winterthur, DE	DEOS MESONET 24 HOUR TOTAL RAINFALL...MOSTLY SINCE 5 PM SUNDAY.
Jul 24, 4:03 AM EDT	HEAVY RAIN 4.76	1 Ese Walnut Ridge, DE	24 HOUR TOTAL AT DEOS WEATHER STATION.

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

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 10.9 hours before the alert went out and 173 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: 186 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 983 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 31 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

956 
WGUS51 KPHI 232253
FFWPHI
DEC003-PAC029-045-240300-
/O.NEW.KPHI.FF.W.0024.170723T2253Z-170724T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
653 PM EDT SUN JUL 23 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Chester County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 1100 PM EDT

* At 652 PM EDT...Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has
  already fallen. Flash flooding is expected to begin shortly in the
  areas of heaviest rain.

* Some locations that could experience flooding include...
  Wilmington, Newark, West Chester, Chester, Coatesville, Westtown,
  Downingtown, Elsmere, Kennett Square, Oxford, Parkesburg, West
  Grove, Honey Brook, Newport, Arden, Glen Roy, Stanton, Cheyney,
  Talleyville and Elam.

Additional rainfall amounts of 2 to 4 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Do not drive through flood waters. The water may be deeper than you 
think it is. A vehicle can easily become trapped in flood waters 
endangering its occupants and those who come to their rescue.

If you live in a flood prone location be prepared to move to higher 
ground.

&&

LAT...LON 3976 7606 3983 7604 3983 7602 3987 7599
      3995 7600 4004 7593 4011 7594 4008 7540
      4006 7539 4006 7535 3982 7538 3977 7546
      3970 7550 3971 7579 3972 7579 3972 7613

$$

Iovino

6 follow-up statements

827 
WGUS71 KPHI 232358
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
758 PM EDT SUN JUL 23 2017

DEC003-PAC029-045-240300-
/O.CON.KPHI.FF.W.0024.000000T0000Z-170724T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
758 PM EDT SUN JUL 23 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 PM EDT FOR
NORTHERN NEW CASTLE...CHESTER AND DELAWARE COUNTIES...

At 755 PM EDT...Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Up to two inches of rain have already 
fallen in much of the area with radar indicating around 4 inches to 
the north of Elsmere in New Castle County. Flash flooding is likely 
occurring.

Some locations that could experience flooding include...
Wilmington, Newark, West Chester, Chester, Coatesville, Westtown,
Downingtown, Elsmere, Kennett Square, Oxford, Parkesburg, West Grove,
Honey Brook, Newport, Arden, Glen Roy, Stanton, Cheyney, Talleyville
and Elam.

Additional rainfall amounts of 2 to 4 inches are possible in the 
warned area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Do not drive through flood waters. The water may be deeper than you 
think it is. A vehicle can easily become trapped in flood waters 
endangering its occupants and those who come to their rescue.

If you live in a flood prone location be prepared to move to higher 
ground.

&&

LAT...LON 3976 7606 3983 7604 3983 7602 3987 7599
      3995 7600 4004 7593 4011 7594 4008 7540
      4006 7539 4006 7535 3982 7538 3977 7546
      3970 7550 3971 7579 3972 7579 3972 7613

$$

Iovino

483 
WGUS51 KPHI 240243
FFWPHI
DEC003-PAC029-045-240900-
/O.EXT.KPHI.FF.W.0024.000000T0000Z-170724T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
1043 PM EDT SUN JUL 23 2017

The National Weather Service in Mount Holly NJ has extended the

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Chester County in southeastern Pennsylvania...
  Delaware County in southeastern Pennsylvania...

* Until 500 AM EDT Monday

* At 1035 PM EDT...Doppler radar and automated rain gauges indicated 
  four to six inches of rain had fallen across northern New Castle 
  County in Delaware, and southeastern Chester and southwestern 
  Delaware Counties in Pennsylvania earlier this evening. 

* Flash flooding will likely continue into the overnight as area 
  creeks and streams continue to rise rapidly in response to the 
  excessive runoff while additional showers and thunderstorms move 
  back into the area.

* Some locations that could experience flooding include...
  Wilmington, Newark, West Chester, Chester, Coatesville, Westtown,
  Downingtown, Elsmere, Kennett Square, Oxford, Parkesburg, West
  Grove, Honey Brook, Newport, Arden, Glen Roy, Stanton, Cheyney,
  Talleyville and Elam.

Additional rainfall amounts of one inch are possible in the warned 
area.

Flood waters are moving down Red Clay Creek from Wooddale to Stanton 
and down Brandywine Creek from Wilmington to locations downstream.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

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 3976 7606 3983 7604 3983 7602 3987 7599
      3995 7600 4004 7593 4011 7594 4008 7540
      4006 7539 4006 7535 3982 7538 3977 7546
      3970 7550 3971 7579 3972 7579 3972 7613

$$

JRK

884 
WGUS71 KPHI 240431
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1231 AM EDT MON JUL 24 2017

DEC003-PAC029-045-240900-
/O.CON.KPHI.FF.W.0024.000000T0000Z-170724T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
1231 AM EDT MON JUL 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 500 AM EDT FOR
NORTHERN NEW CASTLE...CHESTER AND DELAWARE COUNTIES...

At 1217 AM EDT...Doppler radar indicated bands of heavy showers and 
thunderstorms moving northeast from Maryland and these will cross 
the warning area early this morning. Already 3 to 6 inches of rain 
fell last evening from far northern New Castle County Delaware 
across the border into far southeastern Chester County and far 
southwestern Delaware County Pennsylvania. Another 1 to 2 inches may 
fall between now and 6 am in parts of the warning area, aggravating 
an already significant flood situation in far northern New Castle 
County. 

Minor to moderate flooding was occuring on the Red Clay Creek and 
may be occuring on other nearby creeks and streams. The Red Clay 
Creek Wooddale and Stanton was showing signs of leveling off just 
after midnight. It should recede shortly. However, if another 1 to 2 
inches occurs between 1 am and 6 am, it would again rise.  

Some locations that could experience flooding include... Wilmington, 
Newark, West Chester, Chester, Coatesville, Westtown, Downingtown, 
Elsmere, Kennett Square, Oxford, Parkesburg, West Grove, Honey 
Brook, Newport, Arden, Glen Roy, Stanton, Cheyney, Talleyville and 
Elam.



PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3976 7606 3983 7604 3983 7602 3987 7599
      3995 7600 4004 7593 4011 7594 4008 7540
      4006 7539 4006 7535 3982 7538 3977 7546
      3970 7550 3971 7579 3972 7579 3972 7613

$$

Drag

073 
WGUS71 KPHI 240827
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
427 AM EDT MON JUL 24 2017

DEC003-PAC029-045-240900-
/O.CON.KPHI.FF.W.0024.000000T0000Z-170724T0900Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
427 AM EDT MON JUL 24 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 500 AM EDT FOR
NORTHERN NEW CASTLE...SOUTHEASTERN CHESTER AND SOUTHWESTERN DELAWARE
COUNTIES...

At 425 AM EDT...Doppler radar indicated heavy rain across the warned
area.  Flash flooding is already occurring.

The warning area has been reduced to where more than 2.5 inches of 
rain fell last night. The warning will be extended for this area 
through at least sunrise, several minutes after this posts. 

Some locations that could experience flooding include... 
Wilmington, Newark, West Chester, Chester, Westtown, Elsmere, 
Kennett Square, Newport, Arden, Stanton, Cheyney, North Star, 
Talleyville, Elam, Marshallton, Pike Creek, Chelsea, Ashland, 
Greenville and Concordville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

&&

LAT...LON 3998 7572 4001 7566 4005 7564 3998 7551
      3992 7547 3982 7538 3977 7546 3970 7550
      3971 7579 3978 7577 3992 7579

$$

Drag

037 
WGUS51 KPHI 240832
FFWPHI
DEC003-PAC029-045-241300-
/O.EXT.KPHI.FF.W.0024.000000T0000Z-170724T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
432 AM EDT MON JUL 24 2017

The National Weather Service in Mount Holly NJ has extended the

* Flash Flood Warning for...
  Northern New Castle County in northern Delaware...
  Southeastern Chester County in southeastern Pennsylvania...
  Southwestern Delaware County in southeastern Pennsylvania...

* Until 900 AM EDT

* At 428 AM EDT...satellite estimates and rain gauges indicated the 
  rain has ended. Widespread 2.5 to 7.5 inches of rain fell in the 
  warning area last night with considerable flooding reported in far 
  northern Delaware. Some rivers and streams still may crest shortly 
  after sunrise before general recessions ease the disruption. 

* Some locations that could experience flooding include...
  Wilmington, Newark, West Chester, Chester, Westtown, Elsmere,
  Kennett Square, Newport, Arden, Stanton, Cheyney, North Star,
  Talleyville, Elam, Marshallton, Pike Creek, Chelsea, Ashland,
  Greenville and Concordville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...


Excessive runoff from heavy rainfall will cause flooding of small
creeks and streams, urban areas, highways, streets and underpasses as
well as other drainage areas and low lying spots.

Flooding is occurring. It is important to know where you are 
relative to streams, rivers, or creeks which can become killers in 
heavy rains. Campers and hikers should avoid streams or creeks.

&&

LAT...LON 3998 7572 4001 7566 4005 7564 3998 7551
      3992 7547 3982 7538 3977 7546 3970 7550
      3971 7579 3978 7577 3992 7579

$$

Drag

953 
WGUS71 KPHI 241251
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
851 AM EDT MON JUL 24 2017

DEC003-PAC029-045-241300-
/O.EXP.KPHI.FF.W.0024.000000T0000Z-170724T1300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Chester PA-Delaware PA-
851 AM EDT MON JUL 24 2017

...THE FLASH FLOOD WARNING FOR NORTHERN NEW CASTLE...SOUTHEASTERN
CHESTER AND SOUTHWESTERN DELAWARE COUNTIES WILL EXPIRE AT 900 AM
EDT...

The heavy rain has ended. Flood waters have receded. Flooding is no
longer expected to pose a threat. Please continue to heed any
remaining road closures.

LAT...LON 3998 7572 4001 7566 4005 7564 3998 7551
      3992 7547 3982 7538 3977 7546 3970 7550
      3971 7579 3978 7577 3992 7579

$$

LF

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 10:52 PM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Jul 23, 3:16 PM EDT	Flash Flood Watch	PHI	Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more	15 hr
Jul 23, 4:26 PM EDT	Areal Flood Advisory	PHI	Chester	3 hr
Jul 23, 4:48 PM EDT	Areal Flood Advisory	PHI	Chester, Delaware	4 hr
Jul 23, 5:22 PM EDT	Special Weather Statement	PHI	Delaware	23 min
Jul 23, 6:08 PM EDT	Special Weather Statement	PHI	Delaware	37 min
Jul 23, 7:20 PM EDT	Flash Flood Warning	PHI	Berks, Chester, Montgomery	6 hr
Jul 23, 7:41 PM EDT	Flash Flood Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	6 hr
Jul 22, 11:11 PM EDT	Special Weather Statement	PHI	Sussex	64 min
Jul 22, 11:26 PM EDT	Areal Flood Advisory	PHI	Sussex	4 hr
Jul 23, 12:01 AM EDT	Coastal Flood Advisory	PHI	Kent, Sussex	25 hr
Jul 23, 3:53 PM EDT	Areal Flood Advisory	PHI	Kent, New Castle	4 hr
Jul 23, 4:15 PM EDT	Special Weather Statement	PHI	New Castle	30 min
Jul 23, 4:21 PM EDT	Areal Flood Advisory	PHI	Kent	3 hr
Jul 23, 4:29 PM EDT	Severe Thunderstorm Warning	PHI	Kent	26 min
Jul 23, 4:44 PM EDT	Special Weather Statement	PHI	New Castle	16 min

Nearby

Flash Flood Warnings in Pennsylvania, 2017 Flash Flood Warnings in Delaware, 2017 Every flash flood warning in 2017

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.