Alert archive / Pennsylvania / Areal Flood Warnings in 2021

Areal Flood Warning 4, NWS Philadelphia/Mount Holly

March 24, 2021Bucks County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood warning at Mar 24, 2021, 9:42 PM EDT for Bucks County, 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
Mar 24, 2021, 9:42 PM EDT (01:42 UTC)
Expired
Mar 25, 2021, 1:45 AM EDT
In force
4 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon
Flood severity
None

County Bucks County, PA

The radar

The Philadelphia radar (KDIX), 57 km from the middle of the area, began a volume at 01:45 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 00:00Z, 1.7 hours before the alert went out and 195 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, Brookhaven, NY at 00:00Z on 2021-03-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 4 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Brookhaven, NY at 00:00Z on 2021-03-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 209 square meters per square second.19395878Sfc1 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
4 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
510 m above ground
0-6 km bulk shear
39 kt
0-1 km storm-relative helicity
209 m²/s²
0-3 km storm-relative helicity
270 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

796 
WGUS41 KPHI 250142
FLWPHI

BULLETIN - EAS ACTIVATION REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
942 PM EDT Wed Mar 24 2021

PAC017-250545-
/O.NEW.KPHI.FA.W.0004.210325T0142Z-210325T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
942 PM EDT Wed Mar 24 2021

The National Weather Service in Mount Holly has issued a

* Flood Warning for...
  Southeastern Bucks County in southeastern Pennsylvania...

* Until 145 AM EDT.

* At 942 PM EDT, gauge reports indicated minor flooding along the 
  Neshaminy Creek. Flooding is already occurring in the warned area. 
  Between 1 and 1.5 inches of rain have fallen.

For Neshaminy Creek at Langhorne:
At 9:15pm the stage was 7.0 feet.
Flood Stage is 9 feet.
...
For Neshaminy Creek at Penns Park:
At 9:30pm the stage was 13.14 feet.
Flood Stage is 13 feet.

This includes the following highways...
	Pennsylvania Turnpike between exits 353 and 356.
	Interstate 95 in Pennsylvania between mile markers 37 and 40.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 4026 7513 4029 7509 4025 7494 4017 7488
      4009 7487 4008 7493 4011 7494 4019 7505

$$

SFJ
1 follow-up statement
212 
WGUS81 KPHI 250538
FLSPHI

Flood Statement
National Weather Service Mount Holly NJ
138 AM EDT Thu Mar 25 2021

PAC017-250548-
/O.EXP.KPHI.FA.W.0004.000000T0000Z-210325T0545Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Bucks PA-
138 AM EDT Thu Mar 25 2021

...FLOOD WARNING WILL EXPIRE AT 145 AM EDT EARLY THIS MORNING FOR 
SOUTHEASTERN BUCKS COUNTY...

Flood waters have receded. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 4026 7513 4029 7509 4025 7494 4017 7488
      4009 7487 4008 7493 4011 7494 4019 7505

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 24, 8:06 PM EDTRiver Flood WarningPHIChester3 hr
Mar 25, 11:00 AM EDTWind AdvisoryPHIBerks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more32 hr

Nearby

Areal Flood Warnings in Pennsylvania, 2021Every areal flood warning in 2021

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.