Alert archive / Maryland / Flash Flood Warnings in 2018

Flash Flood Warning 2, NWS Philadelphia/Mount Holly

May 12, 2018Caroline County, Kent County, Queen Anne's County, Maryland; Kent County, New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this flash flood warning at May 12, 2018, 8:50 PM EDT for Caroline County, Kent County, Queen Anne's County, Maryland; Kent County, New Castle County, Delaware. It was in force for 3 hr. 1 report 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 12, 2018, 8:50 PM EDT (00:50 UTC)
Expired: May 12, 2018, 11:26 PM EDT
In force: 3 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Kent County, DE, New Castle County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD

The radar

The Dover AFB radar (KDOX), 64 km from the middle of the area, began a volume at 00:52 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 12, 9:30 PM EDT	FLOOD	Little Heaven, DE	THE LEFT LANE OF DELAWARE ROUTE 1 SOUTHBOUND WAS CLOSED.

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 00:00Z, 0.8 hours before the alert went out and 128 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: 1175 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 2284 m above ground
0-6 km bulk shear: 45 kt
0-1 km storm-relative helicity: 132 m²/s²
0-3 km storm-relative helicity: 130 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.4

Open this sounding in Storm Lab

The text

As transmitted.

669 
WGUS51 KPHI 130050
FFWPHI
DEC001-003-MDC011-029-035-130445-
/O.NEW.KPHI.FF.W.0002.180513T0050Z-180513T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
850 PM EDT SAT MAY 12 2018

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Southwestern New Castle County in northern Delaware...
  Kent County in central Delaware...
  Queen Anne's County in northeastern Maryland...
  Northeastern Caroline County in eastern Maryland...
  Kent County in northeastern Maryland...

* Until 1245 AM EDT.

* At 848 PM EDT, Doppler radar and automated rain gauges indicated 
  training thunderstorms producing heavy rain across the warned 
  area. A gauge in Worton, Maryland, reported 2.62 inches of rain in 
  less than an hour. Flash flooding is expected to begin shortly in 
  the areas of heaviest rain.

* Some locations that could experience flooding include...
  Dover, Centerville, Smyrna, Chestertown, Centreville, Camden,
  Clayton, Cheswold, Rock Hall, Church Hill, Millington,
  Sudlersville, Betterton, Bowers, Goldsboro, Woodside, Viola,
  Hartly, Old Town and Hazlettville.

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.

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

&&

LAT...LON 3926 7622 3929 7617 3932 7618 3934 7616
      3933 7614 3937 7611 3938 7604 3936 7589
      3939 7577 3937 7548 3925 7537 3905 7537
      3898 7531 3900 7617 3903 7624 3909 7623
      3917 7628

$$

CMS

2 follow-up statements

389 
WGUS71 KPHI 130231
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1031 PM EDT SAT MAY 12 2018

DEC001-003-MDC011-029-035-130445-
/O.CON.KPHI.FF.W.0002.000000T0000Z-180513T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Kent DE-Queen Anne's MD-Caroline MD-Kent MD-
1031 PM EDT SAT MAY 12 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1245 AM EDT FOR
SOUTHWESTERN NEW CASTLE...KENT...QUEEN ANNE'S...NORTHEASTERN CAROLINE
AND KENT COUNTIES...

At 1030 PM EDT, the Delaware Department of Transportation reported 
lane closures on Route 1 in the Little Heaven area. Though the heavy 
rainfall has ended, rapid runoff will continue, as widespread 2 to 3 
inch rainfall totals have been reported. Flash flooding remains a 
threat.

Some locations that could experience flooding include...
Dover, Centerville, Smyrna, Chestertown, Centreville, Camden,
Clayton, Cheswold, Rock Hall, Church Hill, Millington, Sudlersville,
Betterton, Bowers, Goldsboro, Woodside, Viola, Hartly, Old Town and
Hazlettville.

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.

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

&&

LAT...LON 3926 7622 3929 7617 3932 7618 3934 7616
      3933 7614 3937 7611 3938 7604 3936 7589
      3939 7577 3937 7548 3925 7537 3905 7537
      3898 7531 3900 7617 3903 7624 3909 7623
      3917 7628

$$

CMS

577 
WGUS71 KPHI 130326
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
1126 PM EDT SAT MAY 12 2018

DEC001-003-MDC011-029-035-130335-
/O.CAN.KPHI.FF.W.0002.000000T0000Z-180513T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
New Castle DE-Kent DE-Queen Anne's MD-Caroline MD-Kent MD-
1126 PM EDT SAT MAY 12 2018

...THE FLASH FLOOD WARNING FOR SOUTHWESTERN NEW CASTLE...KENT...QUEEN
ANNE'S...NORTHEASTERN CAROLINE AND KENT COUNTIES IS CANCELLED...

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

LAT...LON 3926 7622 3929 7617 3932 7618 3934 7616
      3933 7614 3937 7611 3938 7604 3936 7589
      3939 7577 3937 7548 3925 7537 3905 7537
      3898 7531 3900 7617 3903 7624 3909 7623
      3917 7628

$$

Iovino

The office that day

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

Issued	Product	Office	Counties	Lasted
May 12, 8:11 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Cecil, Kent, Queen Anne's	49 min
May 12, 8:40 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Kent, Queen Anne's, Talbot	50 min
May 12, 8:51 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Kent, Queen Anne's	39 min
May 12, 9:14 PM EDT	Areal Flood Advisory	PHI	Caroline, Kent, Queen Anne's, Talbot	2 hr
May 12, 9:27 PM EDT	Severe Thunderstorm Warning	PHI	Caroline, Queen Anne's, Talbot	63 min
May 12, 10:28 PM EDT	Areal Flood Advisory	PHI	Sussex	65 min

Nearby

Flash Flood Warnings in Maryland, 2018 Flash Flood Warnings in Delaware, 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.