Alert archive / Pennsylvania / River Flood Warnings in 2018

River Flood Warning 42, NWS Philadelphia/Mount Holly

August 22, 2018Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this river flood warning at Aug 22, 2018, 4:36 AM EDT for Montgomery County, Pennsylvania. It took effect at Aug 22, 2018, 5:00 AM EDT. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Aug 22, 2018, 4:36 AM EDT (08:36 UTC)
In effect from: Aug 22, 2018, 5:00 AM EDT
Expired: Aug 22, 2018, 10:22 AM EDT
In force: 5 hr
Issued by: NWS Philadelphia/Mount Holly
Area: Storm-based polygon
Flood severity: Minor

County Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 08:38 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 river

Written for the forecast point Perkiomen Creek at Graterford (GRAP1).

Action stage: 8 ft
Minor stage: 11 ft
Moderate stage: 13 ft
Major stage: 16 ft

This gauge today: stage, forecast and historic crests

Stage from the USGS instantaneous record for site 01473000, one reading an hour, from a day before the product to a day after it ended. Flood stages are today's.

The text

As transmitted.

185 
WGUS41 KPHI 220836
FLWPHI
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Flood Warning
National Weather Service Mt Holly NJ
436 AM EDT Wed Aug 22 2018

...The National Weather Service in Mount Holly NJ has issued a flood warning for
the following rivers in Pennsylvania...

  Perkiomen Creek At Graterford affecting Montgomery County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SAFETY MESSAGE...Do not attempt to drive through flooded areas. The water may be
deeper than you think.

&&

PAC091-221434-
/O.NEW.KPHI.FL.W.0042.180822T0900Z-180822T2100Z/
/GRAP1.1.ER.180822T0900Z.180822T1200Z.180822T1500Z.NO/
436 AM EDT Wed Aug 22 2018

The National Weather Service in Mount Holly NJ has issued a 

* Flood Warning for 
  The Perkiomen Creek at Graterford.
* until this afternoon...or until the warning is cancelled.
* At 4:17 AM Wednesday the stage was 10.6 feet.
* Flood stage is 11.0 feet.
* Minor flooding is forecast.
* Forecast...Rise above flood stage near sunrise and continue to rise to near 
  11.5 feet by late this morning. The river will fall below flood stage this afternoon.
* Impact...At 12.0 feet...Penitentiary Bridge is closed. Flooding begins in 
  Collegeville. Houses on the right bank in Graterford take on water.
* Flood history...This crest compares to a previous crest of 11.5 feet on Dec 28 
  1993.  

 
&&

                         FLD    OBSERVED           FORECAST
 LOCATION                STG    STG  DAY TIME      CREST

Perkiomen Creek
  Graterford             11.0   10.55  Wed 4 AM    11.6    Wed 8 AM 
 
&&
 
LAT...LON 4024 7549 4024 7542 4011 7542 4012 7547
                                      

$$

CMS

1 follow-up statement

847 
WGUS81 KPHI 221422
FLSPHI
Flood Statement
National Weather Service Mt Holly NJ
1022 AM EDT Wed Aug 22 2018

...The Flood Warning is cancelled for the following rivers in Pennsylvania...

  Perkiomen Creek At Graterford affecting Montgomery County

PRECAUTIONARY/PREPAREDNESS ACTIONS...

SAFETY MESSAGE...Do not attempt to drive through flooded areas. The water may be
deeper than you think.

&&

PAC091-221452-
/O.CAN.KPHI.FL.W.0042.000000T0000Z-180822T2100Z/
/GRAP1.1.ER.180822T0849Z.180822T1132Z.180822T1334Z.NO/
1022 AM EDT Wed Aug 22 2018

The Flood Warning is cancelled for
  The Perkiomen Creek at Graterford.
* At 9:46 AM Wednesday the stage was 10.9 feet.
* Flood stage is 11.0 feet.
* Fell below flood stage at  9:34 AM Wednesday.
* Forecast...The river will continue to fall to 4.3 feet by tomorrow morning.
* Impact...At 12.0 feet...Penitentiary Bridge is closed. Flooding begins in 
  Collegeville. Houses on the right bank in Graterford take on water.


 
&&

                         FLD    OBSERVED           FORECAST
 LOCATION                STG    STG  DAY TIME      CREST

Perkiomen Creek
  Graterford             11.0   10.86  Wed 10 AM   Crested and Falling 
 
&&
 
LAT...LON 4024 7549 4024 7542 4011 7542 4012 7547
                                      

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 21, 8:53 PM EDT	Areal Flood Advisory	PHI	Berks, Chester, Montgomery	5 hr
Aug 21, 10:16 PM EDT	Flash Flood Warning	PHI	Berks, Chester, Montgomery	7 hr
Aug 21, 10:46 PM EDT	Areal Flood Advisory	PHI	Bucks, Lehigh, Northampton	4 hr
Aug 21, 11:08 PM EDT	Flash Flood Warning	PHI	Bucks, Lehigh, Northampton	4 hr
Aug 21, 11:18 PM EDT	Areal Flood Advisory	PHI	Bucks, Chester, Delaware, Montgomery, Philadelphia	3 hr
Aug 21, 11:47 PM EDT	Areal Flood Advisory	PHI	Northampton	4 hr
Aug 22, 1:14 AM EDT	Areal Flood Advisory	PHI	Monroe	4 hr
Aug 22, 2:54 AM EDT	Areal Flood Warning	PHI	Bucks, Lehigh, Northampton	8 hr
Aug 22, 5:14 AM EDT	Areal Flood Warning	PHI	Berks, Chester, Montgomery	4 hr
Aug 22, 10:04 AM EDT	River Flood Warning	PHI	Chester, Montgomery, Philadelphia	5 hr

Nearby

River Flood Warnings in Pennsylvania, 2018 Every river flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; radar from the NEXRAD Level II archive; the gauge from the NWS water service and the USGS.