Alert archive / Maryland / Flash Flood Warnings in 2017

Flash Flood Warning 46, NWS Philadelphia/Mount Holly

August 7, 2017Caroline County, Queen Anne's County, Talbot County, Maryland

NWS Philadelphia/Mount Holly issued this flash flood warning at Aug 7, 2017, 1:35 PM EDT for Caroline County, Queen Anne's County, Talbot 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 7, 2017, 1:35 PM EDT (17:35 UTC)
Expired
Aug 7, 2017, 5:30 PM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

Counties Caroline County, MD, Queen Anne's County, MD, Talbot County, MD

The radar

The Dover AFB radar (KDOX), 64 km from the middle of the area, began a volume at 17:36 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 12:00Z, 5.6 hours before the alert went out and 108 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2017-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 220 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2017-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 72 square meters per square second.1939587897Sfc1 km3 km6 km9 kmRMLM
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
220 J/kg
Mixed-layer CIN
-74 J/kg
Mixed-layer LCL
780 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
72 m²/s²
0-3 km storm-relative helicity
128 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

079 
WGUS51 KPHI 071735
FFWPHI
MDC011-035-041-072130-
/O.NEW.KPHI.FF.W.0046.170807T1735Z-170807T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
135 PM EDT MON AUG 7 2017

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Talbot County in eastern Maryland...
  South central Queen Anne's County in northeastern Maryland...
  Caroline County in eastern Maryland...

* Until 530 PM EDT

* At 133 PM EDT...Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to three inches of rain have
  already fallen. Flash flooding is expected to begin shortly in the 
  areas of heaviest rain. Additional rainfall of a couple of inches 
  is likely over the next few hours. 

* Some locations that could experience flooding include...
  Easton, Talbot, Denton, Federalsburg, Greensboro, Ridgely, Trappe,
  St. Michaels, Preston, Oxford, Queen Anne, Smithville, Copperville,
  Agner, Choptank, Windyhill, Tanyard, Harmony, Tilghman Island and
  Skipton.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Please report flooding to your local law enforcement agency when you
can do so safely. Turn around don't drown. 

&&

LAT...LON 3876 7633 3886 7626 3884 7626 3878 7621
      3888 7620 3900 7574 3867 7571 3870 7590
      3857 7604 3868 7621 3876 7622 3872 7630
      3878 7629 3867 7634 3873 7633 3876 7638

$$

MWG
2 follow-up statements
143 
WGUS71 KPHI 071904
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
304 PM EDT MON AUG 7 2017

MDC011-035-041-072130-
/O.CON.KPHI.FF.W.0046.000000T0000Z-170807T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Talbot MD-Queen Anne's MD-Caroline MD-
304 PM EDT MON AUG 7 2017

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM EDT FOR
TALBOT...SOUTH CENTRAL QUEEN ANNE'S AND CAROLINE COUNTIES...

At 302 PM EDT...Doppler radar indicated thunderstorms producing heavy
rain across the warned area. Up to three inches of rain have already
fallen. Flash flooding is expected to begin shortly.

Some locations that could experience flooding include...
Easton, Talbot, Denton, Federalsburg, Greensboro, Ridgely, Trappe,
St. Michaels, Preston, Oxford, Queen Anne, Smithville, Copperville,
Agner, Choptank, Windyhill, Tanyard, Harmony, Tilghman Island and
Skipton.

Additional rainfall is likely to move back into the warning area 
over the next couple of hours. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3876 7633 3886 7626 3884 7626 3878 7621
      3888 7620 3900 7574 3867 7571 3870 7590
      3857 7604 3868 7621 3876 7622 3872 7630
      3878 7629 3867 7634 3873 7633 3876 7638

$$

MWG
315 
WGUS71 KPHI 072128
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
528 PM EDT MON AUG 7 2017

MDC011-035-041-072136-
/O.EXP.KPHI.FF.W.0046.000000T0000Z-170807T2130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Talbot MD-Queen Anne's MD-Caroline MD-
528 PM EDT MON AUG 7 2017

...THE FLASH FLOOD WARNING FOR TALBOT...SOUTH CENTRAL QUEEN ANNE'S
AND CAROLINE COUNTIES WILL EXPIRE AT 530 PM EDT...

The heavy rain has ended. Flooding is expected in spots that saw the 
heaviest rainfall of three to five inches this afternoon with a 
flood warning in effect through most of the evening. 

LAT...LON 3876 7633 3886 7626 3884 7626 3878 7621
      3888 7620 3900 7574 3867 7571 3870 7590
      3857 7604 3868 7621 3876 7622 3872 7630
      3878 7629 3867 7634 3873 7633 3876 7638

$$

MWG

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 7, 8:54 AM EDTAreal Flood AdvisoryPHICecil, Kent, Queen Anne's3 hr
Aug 7, 10:44 AM EDTFlash Flood WarningPHICaroline, Queen Anne's, Talbot4 hr
Aug 7, 11:41 AM EDTAreal Flood AdvisoryPHICaroline, Talbot3 hr
Aug 7, 2:40 PM EDTAreal Flood WarningPHICaroline, Queen Anne's, Talbot6 hr
Aug 7, 4:32 PM EDTSpecial Weather StatementPHITalbot58 min
Aug 7, 5:25 PM EDTAreal Flood WarningPHICaroline, Queen Anne's, Talbot4 hr

Nearby

Flash Flood Warnings in Maryland, 2017Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.