Alert archive / Pennsylvania / Areal Flood Advisories in 2021

Areal Flood Advisory 112, NWS Philadelphia/Mount Holly

August 11, 2021Carbon County, Monroe County, Pennsylvania

NWS Philadelphia/Mount Holly issued this areal flood advisory at Aug 11, 2021, 5:20 PM EDT for Carbon County, Monroe County, Pennsylvania. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued: Aug 11, 2021, 5:20 PM EDT (21:20 UTC)
Expired: Aug 11, 2021, 6:17 PM EDT
In force: 57 min
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon

Counties Carbon County, PA, Monroe County, PA

The radar

The Binghamton radar (KBGM), 135 km from the middle of the area, began a volume at 21:22 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, 9.3 hours before the alert went out and 210 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: 977 J/kg
Mixed-layer CIN: -44 J/kg
Mixed-layer LCL: 711 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 29 m²/s²
0-3 km storm-relative helicity: 18 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

613 
WGUS81 KPHI 112120
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
520 PM EDT Wed Aug 11 2021

PAC025-089-120030-
/O.NEW.KPHI.FA.Y.0112.210811T2120Z-210812T0030Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carbon PA-Monroe PA-
520 PM EDT Wed Aug 11 2021

The National Weather Service in Mount Holly has issued a

* Flood Advisory for...
  Northeastern Carbon County in northeastern Pennsylvania...
  Central Monroe County in northeastern Pennsylvania...

* Until 830 PM EDT.

* At 520 PM EDT, Doppler radar indicated heavy rain due to 
  thunderstorms. Between 1.5 and 2 inches of rain have fallen in 
  some areas with additional rainfall expected. Minor flooding is 
  ongoing or expected to begin shortly in the advisory area.

* Some locations that will experience flooding include...
  Mount Pocono, East Stroudsburg, Scotrun, Tannersville, Reeders, 
  Paradise Valley, Henryville, McMichael, Alpine Mountain, 
  Analomink, Long Pond, and Pocono Pines.

This includes the following highways...
	Interstate 80 in Pennsylvania between mile markers 287 and 307.
	Interstate 380 in Pennsylvania between mile markers 0 and 5.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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 4110 7558 4114 7548 4116 7536 4116 7516
      4115 7516 4114 7507 4111 7505 4108 7506
      4103 7512 4097 7536 4097 7553 4101 7558
      4103 7559 4107 7559

$$

Robertson

1 follow-up statement

376 
WGUS81 KPHI 112217
FLSPHI

Flood Advisory
National Weather Service Mount Holly NJ
617 PM EDT Wed Aug 11 2021

PAC025-089-112227-
/O.CAN.KPHI.FA.Y.0112.000000T0000Z-210812T0030Z/
/00000.N.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Carbon PA-Monroe PA-
617 PM EDT Wed Aug 11 2021

...FLOOD ADVISORY IS CANCELLED FOR NORTHEASTERN CARBON AND CENTRAL 
MONROE COUNTIES...

The heavy rain has ended and flood waters are receding. Flooding is 
no longer expected to pose a threat. Please continue to heed 
remaining road closures. Additional heavy rainfall is possible at 
times through this evening.

LAT...LON 4110 7558 4114 7548 4116 7536 4116 7516
      4115 7516 4114 7507 4111 7505 4108 7506
      4103 7512 4097 7536 4097 7553 4101 7558
      4103 7559 4107 7559

$$

Robertson

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 10, 8:02 PM EDT	Severe Thunderstorm Warning	PHI	Delaware, Philadelphia	43 min
Aug 10, 8:18 PM EDT	Severe Thunderstorm Warning	PHI	Chester, Delaware, Montgomery	42 min
Aug 10, 8:36 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Delaware, Montgomery, Philadelphia	39 min
Aug 10, 8:43 PM EDT	Areal Flood Advisory	PHI	Delaware, Montgomery, Philadelphia	2 hr
Aug 11, 2:56 PM EDT	Excessive Heat Watch	PHI	Berks, Bucks, Chester, Lehigh, Montgomery, Northampton	12 hr
Aug 11, 4:46 PM EDT	Special Weather Statement	PHI	Monroe	44 min
Aug 11, 4:58 PM EDT	Special Weather Statement	PHI	Berks	47 min
Aug 11, 5:48 PM EDT	Severe Thunderstorm Warning	PHI	Berks	57 min
Aug 11, 6:16 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Lehigh, Montgomery	44 min
Aug 11, 6:26 PM EDT	Severe Thunderstorm Warning	PHI	Berks, Chester, Delaware, Montgomery	49 min
Aug 11, 6:48 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Lehigh, Montgomery, Northampton	42 min
Aug 11, 6:50 PM EDT	Areal Flood Advisory	PHI	Monroe, Northampton	3 hr
Aug 11, 7:04 PM EDT	Areal Flood Advisory	PHI	Berks, Bucks, Chester, Delaware, Lehigh, Montgomery and 2 more	2 hr
Aug 11, 7:11 PM EDT	Severe Thunderstorm Warning	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	49 min

Nearby

Areal Flood Advisories in Pennsylvania, 2021 Every 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.