Alert archive / Pennsylvania / Flash Flood Warnings in 2020

Flash Flood Warning 1, NWS Philadelphia/Mount Holly

April 13, 20204 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this flash flood warning at Apr 13, 2020, 1:07 PM EDT for 4 counties in Pennsylvania. 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: Apr 13, 2020, 1:07 PM EDT (17:07 UTC)
Expired: Apr 13, 2020, 5:00 PM EDT
In force: 4 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

Counties Berks County, PA, Carbon County, PA, Lehigh County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 142 km from the middle of the area, began a volume at 17:08 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, 5.1 hours before the alert went out and 214 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 712 m above ground
0-6 km bulk shear: 75 kt
0-1 km storm-relative helicity: 487 m²/s²
0-3 km storm-relative helicity: 684 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

229 
WGUS51 KPHI 131707
FFWPHI
PAC011-025-077-095-132100-
/O.NEW.KPHI.FF.W.0001.200413T1707Z-200413T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Mount Holly NJ
107 PM EDT Mon Apr 13 2020

The National Weather Service in Mount Holly NJ has issued a

* Flash Flood Warning for...
  Berks County in eastern Pennsylvania...
  Lehigh County in eastern Pennsylvania...
  Southeastern Carbon County in northeastern Pennsylvania...
  West central Northampton County in eastern Pennsylvania...

* Until 500 PM EDT.

* At 104 PM EDT, Doppler radar indicated heavy rain across the 
  warned area. Up to three inches of rain have already fallen today. 
  Another inch is possible across portions of the warned area.

* Some locations that could experience flooding include...
  Allentown, Reading, Wyomissing, Northampton, Palmerton, Kutztown,
  Hamburg, Slatington, Fleetwood, Sinking Spring, Laureldale,
  Womelsdorf, Bath, Wernersville, Walnutport, Topton, Leesport,
  Shoemakersville, Bernville and Lyons.

This includes the following highways...
 Interstate 78 in Pennsylvania between mile markers 28 and 56.
 Northeast Extension near exit A56.
 Interstate 176 in Pennsylvania between mile markers 6 and 11.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

In hilly terrain there are hundreds of low water crossings which are
potentially dangerous in heavy rain. Do not attempt to cross flooded
roads. Find an alternate route.

&&

LAT...LON 4083 7560 4075 7533 4019 7595 4031 7614
      4036 7621 4037 7623 4039 7628

$$

Kruzdlo

1 follow-up statement

332 
WGUS71 KPHI 132051
FFSPHI

Flash Flood Statement
National Weather Service Mount Holly NJ
451 PM EDT Mon Apr 13 2020

PAC011-025-077-095-132100-
/O.EXP.KPHI.FF.W.0001.000000T0000Z-200413T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-Carbon PA-Northampton PA-
451 PM EDT Mon Apr 13 2020

...THE FLASH FLOOD WARNING FOR BERKS...LEHIGH...SOUTHEASTERN CARBON
AND WEST CENTRAL NORTHAMPTON COUNTIES WILL EXPIRE AT 500 PM EDT...

The heavy rain has ended. Please continue to heed any remaining road 
closures.

LAT...LON 4083 7560 4075 7533 4019 7595 4031 7614
      4036 7621 4037 7623 4039 7628

$$

Kruzdlo

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 13, 6:11 AM EDT	Areal Flood Advisory	PHI	Berks, Chester, Delaware, Montgomery	4 hr
Apr 13, 6:48 AM EDT	Areal Flood Advisory	PHI	Delaware, Montgomery, Philadelphia	4 hr
Apr 13, 8:03 AM EDT	Areal Flood Advisory	PHI	Bucks	4 hr
Apr 13, 10:58 AM EDT	River Flood Warning	PHI	Chester	6 hr
Apr 13, 11:09 AM EDT	Areal Flood Warning	PHI	Chester, Delaware	3 hr
Apr 13, 12:29 PM EDT	River Flood Warning	PHI	Chester, Delaware	12 hr
Apr 13, 1:01 PM EDT	Areal Flood Advisory	PHI	Berks, Carbon, Lehigh, Monroe, Northampton	4 hr
Apr 13, 1:27 PM EDT	Severe Thunderstorm Warning	PHI	Chester	33 min
Apr 13, 1:47 PM EDT	Flash Flood Warning	PHI	Chester	3 hr
Apr 13, 2:23 PM EDT	Areal Flood Warning	PHI	Montgomery, Philadelphia	4 hr
Apr 13, 2:37 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	2 hr
Apr 13, 2:41 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware	64 min
Apr 13, 4:35 PM EDT	Areal Flood Warning	PHI	Montgomery	2 hr

Nearby

Flash Flood Warnings in Pennsylvania, 2020 Every flash flood warning in 2020

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.