Alert archive / Pennsylvania / Areal Flood Warnings in 2021
Areal Flood Warning 2, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this areal flood warning at Mar 24, 2021, 6:26 PM EDT for Montgomery County, Philadelphia County, Pennsylvania. It was in force for 10 hr. 4 reports came from inside the area while it was in force.
The area
The outline as issued, with what was reported inside it.
The facts
- Issued
- Mar 24, 2021, 6:26 PM EDT (22:26 UTC)
- Expired
- Mar 25, 2021, 4:30 AM EDT
- In force
- 10 hr
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Flood severity
- None
Counties Montgomery County, PA, Philadelphia County, PA
The radar
The Philadelphia radar (KDIX), 71 km from the middle of the area, began a volume at 22:29 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.
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Mar 24, 7:15 PM EDT | FLOOD | 1 Nnw Flourtown, PA | GAGE ALONG THE WISSAHICKON CREEK NEAR FORT WASHINGTON WENT INTO MINOR FLOOD. |
| Mar 24, 7:47 PM EDT | HEAVY RAIN 2.35 | Chestnut Hill, PA | SOCIAL MEDIA. |
| Mar 24, 8:19 PM EDT | FLOOD | 1 Nnw Flourtown, PA | BETHLEHEM PIKE AT MATHERS LANE WAS CLOSED FROM FLOODING. TIME BASED ON DISPATCH REPORT. |
| Mar 24, 9:15 PM EDT | FLOOD | 1 Sse Manayunk, PA | WISSAHICKON CREEK AT WISSAHICKON (PHAP1) REACHED MINOR FLOOD STAGE AT 915 PM AND IS STILL RISING CURRENTLY. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Brookhaven, NY (KOKX), launched 12:00Z, 10.4 hours before the alert went out and 218 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1342 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- 82 m²/s²
- 0-3 km storm-relative helicity
- 135 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
834
WGUS41 KPHI 242226
FLWPHI
BULLETIN - EAS ACTIVATION REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
626 PM EDT Wed Mar 24 2021
PAC091-101-250430-
/O.NEW.KPHI.FA.W.0002.210324T2226Z-210325T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
626 PM EDT Wed Mar 24 2021
The National Weather Service in Mount Holly has issued a
* Flood Warning for...
South Central Montgomery County in southeastern Pennsylvania...
West Central Philadelphia County in southeastern Pennsylvania...
* Until 1230 AM EDT Thursday.
* At 626 PM EDT, Doppler radar and automated rain gauges indicated
heavy rain. Flooding is ongoing or expected to begin shortly in
the warned area. Between 1 and 2 inches of rain have fallen.
* Flooding is expected along the Wissahickon Creek.
For Wissahickon Creek at Fort Washington:
At 6:00pm the stage was 9.21 feet.
Flood Stage is 10 feet.
...
For Wissahickon Creek at Wissahickon:
At 6:00pm the stage was 4.08 feet.
Flood Stage is 5 feet.
This includes the following highways...
Pennsylvania Turnpike between exits 336 and 337.
Interstate 76 in Pennsylvania near mile marker 340.
Additional rainfall amounts up to 0.5 inches are possible in the
warned area.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4007 7523 4010 7526 4011 7523 4015 7525
4015 7522 4011 7520 4009 7522 4006 7520
4003 7518 4001 7520 4002 7522
$$
SFJ4 follow-up statements
256
WGUS81 KPHI 250224
FLSPHI
Flood Statement
National Weather Service Mount Holly NJ
1024 PM EDT Wed Mar 24 2021
PAC091-101-250430-
/O.CON.KPHI.FA.W.0002.000000T0000Z-210325T0430Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
1024 PM EDT Wed Mar 24 2021
...FLOOD WARNING REMAINS IN EFFECT UNTIL 1230 AM EDT THURSDAY FOR
SOUTH CENTRAL MONTGOMERY AND WEST CENTRAL PHILADELPHIA COUNTIES...
At 1024 PM EDT, gauge reports along the Wissahickon Creek indicated
minor flooding is occurring. Between 1 and 2.5 inches of rain have
fallen.
For Wissahickon Creek at Wissahickon:
At 10:00pm the stage was 5.22 feet.
Flood Stage is 5 feet.
This includes the following highways...
Pennsylvania Turnpike between exits 336 and 337.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Be especially cautious at night when it is harder to recognize the
dangers of flooding.
&&
LAT...LON 4007 7523 4010 7526 4011 7523 4015 7525
4015 7522 4011 7520 4009 7522 4006 7520
4003 7518 4001 7520 4002 7522
$$
SFJ726
WGUS41 KPHI 250410
FLWPHI
BULLETIN - EAS ACTIVATION REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
1210 AM EDT Thu Mar 25 2021
PAC091-101-250630-
/O.EXT.KPHI.FA.W.0002.000000T0000Z-210325T0630Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
1210 AM EDT Thu Mar 25 2021
The National Weather Service in Mount Holly has extended the
* Flood Warning for...
South Central Montgomery County in southeastern Pennsylvania...
West Central Philadelphia County in southeastern Pennsylvania...
* Until 230 AM EDT.
* At 1210 AM EDT, gauge reports indicated minor flooding continuing
on Wissahickon Creek, with levels still rising at Wissahickon.
Flooding is expected to continue along the creek for the next
couple of hours.
For Wissahickon Creek at Wissahickon:
At 11:00pm the stage was 5.5 feet.
Flood Stage is 5 feet.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4007 7523 4010 7526 4011 7523 4015 7525
4015 7522 4011 7520 4009 7522 4006 7520
4003 7518 4001 7520 4002 7522
$$
CMS715
WGUS41 KPHI 250613
FLWPHI
BULLETIN - EAS ACTIVATION REQUESTED
Flood Warning
National Weather Service Mount Holly NJ
213 AM EDT Thu Mar 25 2021
PAC091-101-250830-
/O.EXT.KPHI.FA.W.0002.000000T0000Z-210325T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
213 AM EDT Thu Mar 25 2021
The National Weather Service in Mount Holly has extended the
* Flood Warning for...
South Central Montgomery County in southeastern Pennsylvania...
West Central Philadelphia County in southeastern Pennsylvania...
* Until 430 AM EDT.
* At 213 AM EDT, gauge reports on Wissahickon Creek indicate minor
flooding is continuing in the Wissahickon area. The creek has
crested, but flooding will likely continue for the next couple of
hours.
For Wissahickon Creek at Wissahickon:
At 1:00am the stage was 5.61 feet.
Flood Stage is 5 feet.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Turn around...don't drown when encountering flooded roads. Most
flood deaths occur in vehicles.
&&
LAT...LON 4007 7523 4010 7526 4011 7523 4015 7525
4015 7522 4011 7520 4009 7522 4006 7520
4003 7518 4001 7520 4002 7522
$$
CMS788
WGUS81 KPHI 250824
FLSPHI
Flood Statement
National Weather Service Mount Holly NJ
424 AM EDT Thu Mar 25 2021
PAC091-101-250834-
/O.EXP.KPHI.FA.W.0002.000000T0000Z-210325T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Montgomery PA-Philadelphia PA-
424 AM EDT Thu Mar 25 2021
...FLOOD WARNING WILL EXPIRE AT 430 AM EDT EARLY THIS MORNING FOR
SOUTH CENTRAL MONTGOMERY AND WEST CENTRAL PHILADELPHIA COUNTIES...
Flood waters have receded. Flooding is no longer expected to pose a
threat. Please continue to heed remaining road closures.
LAT...LON 4007 7523 4010 7526 4011 7523 4015 7525
4015 7522 4011 7520 4009 7522 4006 7520
4003 7518 4001 7520 4002 7522
$$
CMSThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 24, 1:51 PM EDT | Areal Flood Advisory | PHI | Bucks, Chester, Delaware, Montgomery, Philadelphia | 5 hr |
| Mar 24, 2:45 PM EDT | Areal Flood Advisory | PHI | Berks, Bucks, Chester, Montgomery | 5 hr |
| Mar 24, 7:09 PM EDT | Dense Fog Advisory | PHI | Berks, Bucks, Carbon, Chester, Delaware, Lehigh and 4 more | 14 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.