Alert archive / Pennsylvania / Severe Thunderstorm Warnings in 2026
Severe Thunderstorm Warning 308, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this severe thunderstorm warning at Aug 17, 2026, 6:03 PM EDT for Berks County, Chester County, Montgomery County, Pennsylvania. It was in force for 42 min. 1 report 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
- Aug 17, 2026, 6:03 PM EDT (22:03 UTC)
- Expired
- Aug 17, 2026, 6:45 PM EDT
- In force
- 42 min
- Issued by
- NWS Philadelphia/Mount Holly
- Area
- Storm-based polygon
Counties Berks County, PA, Chester County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 118 km from the middle of the area, began a volume at 22:05 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 |
|---|---|---|---|
| Aug 17, 6:25 PM EDT | TSTM WND DMG | Douglassville, PA | Tree down. Time estimated from radar. |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Washington/Dulle, VA (KIAD), launched 12:00Z, 10.1 hours before the alert went out and 198 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
- 154 J/kg
- Mixed-layer CIN
- -50 J/kg
- Mixed-layer LCL
- 877 m above ground
- 0-6 km bulk shear
- 23 kt
- 0-1 km storm-relative helicity
- 77 m²/s²
- 0-3 km storm-relative helicity
- 59 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.1
The text
As transmitted.
316
WUUS51 KPHI 172203
SVRPHI
PAC011-029-091-172245-
/O.NEW.KPHI.SV.W.0308.260817T2203Z-260817T2245Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Mount Holly NJ
Issued by National Weather Service Baltimore MD/Washington DC
603 PM EDT Mon Aug 17 2026
The National Weather Service in Mount Holly NJ has issued a
* Severe Thunderstorm Warning for...
Southeastern Berks County in eastern Pennsylvania...
West central Montgomery County in southeastern Pennsylvania...
North central Chester County in southeastern Pennsylvania...
* Until 645 PM EDT.
* At 601 PM EDT, a severe thunderstorm was located over Flying Hills
and Mohnton, and moving southeast at 25 mph.
* HAZARD...60 mph wind gusts and quarter size hail.
* SOURCE...Radar indicated.
* Locations impacted include...
Birdsboro, New Morgan, Mohnton, Elverson Honey Brook, and
Glenmoore
PRECAUTIONARY/PREPAREDNESS ACTIONS...
&&
LAT...LON 4045 7587 4028 7566 4025 7569 4025 7567
4022 7561 4023 7560 4020 7558 4017 7553
4015 7553 4015 7551 3998 7591 4001 7596
4004 7594 4011 7594 4014 7588 4032 7616
TIME...MOT...LOC 2201Z 326DEG 22KT 4023 7595
$$
EST3 follow-up statements
835
WWUS51 KPHI 172209
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service Baltimore MD/Washington DC
609 PM EDT Mon Aug 17 2026
PAC011-029-091-172245-
/O.CON.KPHI.SV.W.0308.000000T0000Z-260817T2245Z/
Berks PA-Montgomery PA-Chester PA-
609 PM EDT Mon Aug 17 2026
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR SOUTHEASTERN BERKS...WEST CENTRAL MONTGOMERY AND NORTH CENTRAL
CHESTER COUNTIES...
At 609 PM EDT, severe thunderstorm was located over Flying Hills and
Mohnton, and moving southeast at 25 mph.
* HAZARD...60 mph wind gusts and quarter size hail.
* SOURCE...Radar indicated.
* Locations impacted include...
Birdsboro, New Morgan, Mohnton, Elverson Honey Brook, and
Glenmoore
PRECAUTIONARY/PREPAREDNESS ACTIONS...
&&
LAT...LON 4028 7566 4025 7569 4025 7567 4022 7561
4023 7560 4020 7558 4017 7553 4015 7553
4015 7551 3998 7591 4001 7596 4004 7594
4011 7594 4014 7588 4028 7610 4040 7581
TIME...MOT...LOC 2209Z 326DEG 22KT 4019 7591
$$
EST363
WWUS51 KPHI 172227
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service Baltimore MD/Washington DC
627 PM EDT Mon Aug 17 2026
PAC011-029-091-172245-
/O.CON.KPHI.SV.W.0308.000000T0000Z-260817T2245Z/
Berks PA-Montgomery PA-Chester PA-
627 PM EDT Mon Aug 17 2026
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 645 PM EDT
FOR SOUTHEASTERN BERKS...WESTERN MONTGOMERY AND NORTH CENTRAL CHESTER
COUNTIES...
At 625 PM EDT, a severe thunderstorms was located near New Morgan ,
moving southeast at 25 mph.
* HAZARD...60 mph wind gusts.
* SOURCE...Radar indicated.
* LOCATIONS IMPACTED INCLUDE... Honey Brook, ELverson, New Morgan,
and Glenmoore.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
&&
LAT...LON 4024 7603 4034 7574 4031 7570 4027 7567
4025 7569 4025 7566 4012 7559 3998 7591
4001 7596 4004 7594 4011 7594 4014 7588
TIME...MOT...LOC 2225Z 325DEG 21KT 4014 7586
$$
EST263
WWUS51 KPHI 172240
SVSPHI
Severe Weather Statement
National Weather Service Mount Holly NJ
Issued by National Weather Service Baltimore MD/Washington DC
640 PM EDT Mon Aug 17 2026
PAC011-029-091-172250-
/O.EXP.KPHI.SV.W.0308.000000T0000Z-260817T2245Z/
Berks PA-Montgomery PA-Chester PA-
640 PM EDT Mon Aug 17 2026
...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN BERKS...WESTERN
MONTGOMERY AND NORTH CENTRAL CHESTER COUNTIES WILL EXPIRE AT 645 PM
EDT...
The severe thunderstorm which prompted the warning has weakened.
Therefore the warning will be allowed to expire.
LAT...LON 4024 7603 4034 7574 4031 7570 4027 7567
4025 7569 4025 7566 4012 7559 3998 7591
4001 7596 4004 7594 4011 7594 4014 7588
TIME...MOT...LOC 2240Z 326DEG 22KT 4009 7581
$$
ESTThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 16, 11:21 PM EDT | Flash Flood Warning | PHI | Chester, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 16, 11:38 PM EDT | Flash Flood Warning | PHI | Bucks, Delaware, Montgomery, Philadelphia | 4 hr |
| Aug 17, 1:57 AM EDT | Flash Flood Warning | PHI | Bucks, Montgomery, Philadelphia | 4 hr |
| Aug 17, 4:43 PM EDT | Special Weather Statement | PHI | Berks | 47 min |
| Aug 17, 5:09 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 36 min |
| Aug 17, 5:30 PM EDT | Special Weather Statement | PHI | Berks | 30 min |
| Aug 17, 6:45 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 32 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.