Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 36, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at May 20, 2026, 4:46 PM EDT for 4 counties in Pennsylvania. It was in force for 44 min. 15 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
- May 20, 2026, 4:46 PM EDT (20:46 UTC)
- Expired
- May 20, 2026, 5:30 PM EDT
- In force
- 44 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
Counties Berks County, PA, Bucks County, PA, Lehigh County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 120 km from the middle of the area, began a volume at 20:47 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 |
|---|---|---|---|
| May 20, 4:47 PM EDT | TSTM WND DMG | 1 Nne Pottstown, PA | Several trees and large tree limbs down on Charlotte Street and Diamond Street. Time estimated from KDIX radar. |
| May 20, 4:47 PM EDT | TSTM WND DMG | 1 Nne Pottstown, PA | Several trees and large tree limbs down on Charlotte Street and Diamond Street. Time estimated from KDIX radar. |
| May 20, 4:47 PM EDT | TSTM WND DMG | 2 Se Douglass Twp, PA | Wires down along Sunset Drive. Time estimated from radar. |
| May 20, 4:47 PM EDT | TSTM WND DMG | 2 Se Douglass Twp, PA | Wires down along Sunset Drive. Time estimated from radar. |
| May 20, 4:48 PM EDT | TSTM WND DMG | Pottstown, PA | Picture sent in via social media of multiple trees down. Time estimated from radar. |
| May 20, 4:48 PM EDT | TSTM WND DMG | Pottstown, PA | Picture sent in via social media of multiple trees down. Time estimated from radar. |
| May 20, 4:50 PM EDT | TSTM WND DMG | East Greenville, PA | Trees and wires down in East Greenville. Time estimated from radar. |
| May 20, 4:50 PM EDT | TSTM WND DMG | East Greenville, PA | Trees and wires down in East Greenville. Time estimated from radar. |
| May 20, 4:56 PM EDT | TSTM WND GST 51 | 2 Ese Sanatoga, PA | ASOS station KPTW Pottstown. |
| May 20, 4:59 PM EDT | TSTM WND DMG | 3 Ese Lower Pottsgrove, PA | Trees down around Limerick, PA. Time estimated from radar. |
| May 20, 4:59 PM EDT | TSTM WND DMG | 3 Ese Lower Pottsgrove, PA | Trees down around Limerick, PA. Time estimated from radar. |
| May 20, 5:03 PM EDT | TSTM WND DMG | 1 Ene New Hanover Twp, PA | Widespread trees and wires down in New Hanover Township, PA. Time estimated from radar. |
| May 20, 5:03 PM EDT | TSTM WND DMG | 1 Ene New Hanover Twp, PA | Widespread trees and wires down in New Hanover Township, PA. Time estimated from radar. |
| May 20, 5:25 PM EDT | TSTM WND DMG | 2 Nnw Montgomeryville, PA | Trees and wires down around Colmar. Time estimated from radar. |
| May 20, 5:25 PM EDT | TSTM WND DMG | 2 Nnw Montgomeryville, PA | Trees and wires down around Colmar. Time estimated from radar. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The watch it was issued in
The SPC watch in force over the same counties when this warning went out.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| May 20, 2:10 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 8.8 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.
- Mixed-layer CAPE
- 47 J/kg
- Mixed-layer CIN
- -204 J/kg
- Mixed-layer LCL
- 1752 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- -79 m²/s²
- 0-3 km storm-relative helicity
- -47 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
448
WUUS51 KPHI 202046
SVRPHI
PAC011-017-077-091-202130-
/O.NEW.KPHI.SV.W.0036.260520T2046Z-260520T2130Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
446 PM EDT Wed May 20 2026
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Southeastern Berks County in eastern Pennsylvania...
Northwestern Montgomery County in southeastern Pennsylvania...
South central Lehigh County in eastern Pennsylvania...
West central Bucks County in southeastern Pennsylvania...
* Until 530 PM EDT.
* At 446 PM EDT, a severe thunderstorm was located near Laureldale,
or near Reading, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
* Locations impacted include...
Reading, Pottstown, Lansdale, Wyomissing, Quakertown, Perkasie,
Souderton, Birdsboro, Fleetwood, Chalfont, Laureldale, Hatfield,
East Greenville, Dublin, Leesport, Schwenksville, Bally,
Bechtelsville, Green Lane, and Lyons.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4048 7596 4050 7583 4043 7520 4020 7523
4027 7600
TIME...MOT...LOC 2046Z 275DEG 31KT 4038 7584
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
Fitzsimmons1 follow-up statement
023
WWUS51 KPHI 202105
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
505 PM EDT Wed May 20 2026
PAC011-017-077-091-202130-
/O.CON.KPHI.SV.W.0036.000000T0000Z-260520T2130Z/
Berks PA-Montgomery PA-Lehigh PA-Bucks PA-
505 PM EDT Wed May 20 2026
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 530 PM EDT
FOR EAST CENTRAL BERKS...NORTHWESTERN MONTGOMERY...SOUTH CENTRAL
LEHIGH AND WEST CENTRAL BUCKS COUNTIES...
At 505 PM EDT, a severe thunderstorm was located over Green Lane, or
19 miles south of Allentown, moving east at 35 mph.
HAZARD...60 mph wind gusts.
SOURCE...Radar indicated.
IMPACT...Damage to roofs, siding, trees, and power lines is
possible.
Locations impacted include...
Pottstown, Lansdale, Quakertown, Perkasie, Souderton, Chalfont,
Hatfield, East Greenville, Dublin, Schwenksville, Bally, Green Lane,
Fricks, Spring Mount, Geryville, Gilbertsville, Skippack, Telford,
Sellersville, and Pennsburg.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 4024 7565 4047 7558 4043 7520 4020 7523
4023 7552
TIME...MOT...LOC 2105Z 275DEG 29KT 4031 7546
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...<.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
FitzsimmonsThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 19, 8:04 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 25 min |
| May 20, 3:57 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Lehigh | 48 min |
| May 20, 4:00 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 45 min |
| May 20, 4:29 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Chester, Montgomery | 46 min |
| May 20, 4:43 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Lehigh, Northampton | 47 min |
| May 20, 4:50 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 40 min |
| May 20, 5:10 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 50 min |
| May 20, 5:15 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Chester, Montgomery, Philadelphia | 45 min |
| May 20, 5:24 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Northampton | 51 min |
| May 20, 5:29 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware, Philadelphia | 46 min |
| May 20, 5:40 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 3 hr |
| May 20, 5:41 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 49 min |
| May 20, 5:52 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 38 min |
| May 20, 6:01 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Montgomery, Philadelphia | 44 min |
| May 20, 6:09 PM EDT | Severe Thunderstorm Warning | PHI | Delaware, Philadelphia | 46 min |
Nearby
Severe Thunderstorm Warnings in Pennsylvania, 2026Every severe thunderstorm warning in 2026
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.