Alert archive / Pennsylvania / Areal Flood Warnings in 2020

Areal Flood Warning 13, NWS Philadelphia/Mount Holly

April 13, 2020Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Apr 13, 2020, 4:35 PM EDT for Montgomery County, Pennsylvania. It was in force for 2 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, 4:35 PM EDT (20:35 UTC)
Expired: Apr 13, 2020, 7:04 PM EDT
In force: 2 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: None

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 20:37 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

Brookhaven, NY (KOKX), launched 12:00Z, 8.6 hours before the alert went out and 223 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: 5 J/kg
Mixed-layer CIN: -30 J/kg
Mixed-layer LCL: 428 m above ground
0-6 km bulk shear: 38 kt
0-1 km storm-relative helicity: 455 m²/s²
0-3 km storm-relative helicity: 813 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

188 
WGUS41 KPHI 132035
FLWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
435 PM EDT Mon Apr 13 2020

PAC091-140030-
/O.NEW.KPHI.FA.W.0013.200413T2035Z-200414T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-
435 PM EDT Mon Apr 13 2020

The National Weather Service in Mount Holly NJ has issued a

* Flood Warning for...
  North central Montgomery County in southeastern Pennsylvania...

* Until 830 PM EDT.

* At 431 PM EDT, the gauge at Schwenksville on the East Branch 
  Perkiomen has risen to Flood Stage. Flood stage is 8.0 feet. At 
  8.0 feet, Bergey's Mill Park in Lower Salford begins to flood. The 
  access road in and out of the park floods.

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 4035 7539 4031 7532 4023 7541 4027 7548

$$

Kruzdlo

1 follow-up statement

797 
WGUS81 KPHI 132304
FLSPHI

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

PAC091-132312-
/O.CAN.KPHI.FA.W.0013.000000T0000Z-200414T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-
704 PM EDT Mon Apr 13 2020

...THE FLOOD WARNING HAS BEEN CANCELLED FOR NORTH CENTRAL MONTGOMERY
COUNTY...

Flood waters were receding early this evening, and are no longer 
expected to pose a threat to life or property. Please continue to 
heed any road closures.

LAT...LON 4035 7539 4031 7532 4023 7541 4027 7548

$$

Iovino

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, 1:07 PM EDT	Flash Flood Warning	PHI	Berks, Carbon, Lehigh, 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

Nearby

Areal Flood Warnings in Pennsylvania, 2020 Every areal 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.