Alert archive / Pennsylvania / Areal Flood Advisories in 2021

Areal Flood Advisory 13, NWS Philadelphia/Mount Holly

June 4, 2021Berks County, Lehigh County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood advisory at Jun 4, 2021, 1:29 PM EDT for Berks County, Lehigh County, Pennsylvania. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jun 4, 2021, 1:29 PM EDT (17:29 UTC)
Expired
Jun 4, 2021, 3:30 PM EDT
In force
2 hr
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Berks County, PA, Lehigh County, PA

The radar

The Philadelphia radar (KDIX), 150 km from the middle of the area, began a volume at 17:30 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, 5.5 hours before the alert went out and 217 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 2021-06-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 381 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, Washington/Dulle, VA at 12:00Z on 2021-06-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -8 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
381 J/kg
Mixed-layer CIN
-55 J/kg
Mixed-layer LCL
947 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
-8 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.1

Open this sounding in Storm Lab

The text

As transmitted.

654 
WGUS81 KPHI 041729
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
129 PM EDT Fri Jun 4 2021

PAC011-077-041930-
/O.NEW.KPHI.FA.Y.0013.210604T1729Z-210604T1930Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Berks PA-Lehigh PA-
129 PM EDT Fri Jun 4 2021

The National Weather Service in Mount Holly has issued a

* Flood Advisory for...
  Northeastern Berks County in eastern Pennsylvania...
  Central Lehigh County in eastern Pennsylvania...

* Until 330 PM EDT.

* At 129 PM EDT, Doppler radar and automated rain gauges indicated 
  heavy rain due to thunderstorms. Minor flooding is ongoing or 
  expected to begin shortly in the advisory area. Between 0.5 and 1 
  inch of rain has fallen. An additional 0.5 to 1 inch of rain is 
  possible.

* Flooding of low lying and poor drainage areas is expected.

* Some locations that will experience flooding include...
  Kutztown, Hamburg, Topton, Shoemakersville, Lyons, Strausstown, 
  Lenhartsville, Claussville, Alburtis, and Centerport.

This includes the following highways...
	Interstate 78 in Pennsylvania between mile markers 19 and 51.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 4066 7562 4047 7560 4049 7621 4053 7619
      4054 7617 4055 7613 4057 7608 4058 7607
      4057 7605 4058 7604 4057 7602 4061 7600

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Jun 3, 8:44 PM EDTSevere Thunderstorm WarningPHIBucks30 min
Jun 4, 1:02 PM EDTSpecial Weather StatementPHILehigh28 min
Jun 4, 1:07 PM EDTSpecial Weather StatementPHICarbon, Monroe38 min
Jun 4, 1:45 PM EDTAreal Flood AdvisoryPHIMonroe, Northampton97 min
Jun 4, 1:49 PM EDTSevere Thunderstorm WarningPHIMonroe, Northampton41 min
Jun 4, 2:21 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Lehigh, Montgomery21 min
Jun 4, 2:24 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery51 min
Jun 4, 2:27 PM EDTSevere Thunderstorm WarningPHIBerks48 min
Jun 4, 3:14 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia46 min
Jun 4, 3:16 PM EDTAreal Flood AdvisoryPHIBucks, Chester, Delaware, Montgomery, Philadelphia98 min
Jun 4, 3:18 PM EDTSevere Thunderstorm WarningPHIBucks42 min
Jun 4, 3:23 PM EDTSevere Thunderstorm WarningPHIBucks67 min
Jun 4, 3:46 PM EDTSevere Thunderstorm WarningPHIBucks, Philadelphia44 min
Jun 4, 4:20 PM EDTSevere Thunderstorm WarningPHIPhiladelphia40 min

Nearby

Areal Flood Advisories in Pennsylvania, 2021Every areal flood advisory 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.