Alert archive / Maryland / Flash Flood Warnings in 2015

Flash Flood Warning 47, NWS Philadelphia/Mount Holly

August 20, 2015Cecil County, Kent County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 20, 2015, 8:50 PM EDT for Cecil County, Kent County, Maryland. It was in force for 4 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 20, 2015, 8:50 PM EDT (00:50 UTC)
Expired: Aug 21, 2015, 12:45 AM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Cecil County, MD, Kent County, MD

The radar

The Dover AFB radar (KDOX), 78 km from the middle of the area, began a volume at 00:51 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

Washington/Dulle, VA (KIAD), launched 00:00Z, 0.8 hours before the alert went out and 119 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: 38 J/kg
Mixed-layer CIN: -155 J/kg
Mixed-layer LCL: 1117 m above ground
0-6 km bulk shear: 22 kt
0-1 km storm-relative helicity: -78 m²/s²
0-3 km storm-relative helicity: -8 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

528 
WGUS51 KPHI 210050
FFWPHI
MDC015-029-210445-
/O.NEW.KPHI.FF.W.0047.150821T0050Z-150821T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
850 PM EDT THU AUG 20 2015

THE NATIONAL WEATHER SERVICE IN MOUNT HOLLY NJ  HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTHWESTERN KENT COUNTY IN NORTHEASTERN MARYLAND...
  SOUTHERN CECIL COUNTY IN NORTHEASTERN MARYLAND...

* UNTIL 1245 AM EDT
    
* AT 848 PM EDT...DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING 
  HEAVY RAIN ACROSS THE WARNED AREA. TWO TO TWO AND A HALF INCHES OF 
  RAIN HAVE ALREADY FALLEN WITHIN THE LAST HOUR AND A HALF. 
  ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO INCHES ARE POSSIBLE IN 
  THE WARNED AREA. FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...
  CHESTERTOWN...NEWTOWN...KENNEDYVILLE AND MORGNEC. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING.

TURN AROUND...DON'T DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 3928 7620 3929 7617 3932 7618 3933 7614
      3938 7601 3938 7595 3937 7594 3935 7593
      3926 7597 3917 7624 3922 7625

$$

ROBERTSON

1 follow-up statement

368 
WGUS71 KPHI 210240
FFSPHI

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1040 PM EDT THU AUG 20 2015

MDC015-029-210250-
/O.CAN.KPHI.FF.W.0047.000000T0000Z-150821T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
KENT MD-CECIL MD-
1040 PM EDT THU AUG 20 2015

...THE FLASH FLOOD WARNING FOR NORTHWESTERN KENT AND SOUTHERN CECIL
COUNTIES IS CANCELLED...

THE HEAVY RAIN HAS ENDED...AND FLOODING IS NO LONGER EXPECTED TO POSE
A THREAT.

LAT...LON 3928 7620 3929 7617 3932 7618 3933 7614
      3938 7601 3938 7595 3937 7594 3935 7593
      3926 7597 3917 7624 3922 7625

$$

HEAVENER

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 8:08 PM EDT	Areal Flood Advisory	PHI	Caroline, Cecil, Kent, Queen Anne's, Talbot	4 hr
Aug 20, 8:40 PM EDT	Special Weather Statement	PHI	Kent	50 min

Nearby

Flash Flood Warnings in Maryland, 2015 Every flash flood warning in 2015

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.