Alert archive / Pennsylvania / Special Weather Statements in 2021
Special Weather Statement, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this special weather statement at Jul 21, 2021, 2:41 PM EDT for Montgomery County, Pennsylvania. It was in force for 49 min. 14 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
- Jul 21, 2021, 2:41 PM EDT (18:41 UTC)
- Expired
- Jul 21, 2021, 3:30 PM EDT
- In force
- 49 min
- Issued by
- NWS Philadelphia/Mount Holly
County Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 94 km from the middle of the area, began a volume at 18:44 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 |
|---|---|---|---|
| Jul 21, 2:50 PM EDT | HAIL 0.88 | Schwenksville, PA | |
| Jul 21, 3:05 PM EDT | TSTM WND DMG | East Norriton, PA | NUMEROUS TREES DOWN. |
| Jul 21, 3:05 PM EDT | HAIL 1 | East Norriton, PA | |
| Jul 21, 3:07 PM EDT | TSTM WND DMG | North Wales, PA | PHOTO OF LARGE TREE DOWN IN UPPER GWYNEDD TOWNSHIP. TIME ESTIMATED FROM RADAR. |
| Jul 21, 3:10 PM EDT | TSTM WND DMG | 1 Wnw Blue Bell, PA | NUMEROUS TREES DOWN ON WIRES IN WHITPAIN TOWNSHIP. TIME ESTIMATED FROM RADAR. |
| Jul 21, 3:10 PM EDT | TSTM WND GST 51 | Plymouth Meeting, PA | |
| Jul 21, 3:10 PM EDT | HAIL 1 | Plymouth Meeting, PA | |
| Jul 21, 3:11 PM EDT | HAIL 1 | Plymouth Twp, PA | HAIL, TO THE SIZE OF QUARTERS (FROM MPING). |
| Jul 21, 3:15 PM EDT | TSTM WND DMG | 2 Wnw Blue Bell, PA | NUMEROUS PHOTOS OF LARGE TREE LIMBS DOWN IN THE IN THE CENTER SQUARE AREA OF BLUE BELL. TIME ESTIMATED FROM RADAR. |
| Jul 21, 3:15 PM EDT | HAIL 1.25 | Blue Bell, PA | PHOTOS RELAYED ON SOCIAL MEDIA, OF HAIL SLIGHTLY LARGER THAN QUARTER SIZE. TIME ESTIMATED FROM RADAR. |
| Jul 21, 3:20 PM EDT | TSTM WND DMG | 1 S Fort Washington, PA | TREES DOWN NEAR THE PENNSYLVANIA TURNPIKE. |
| Jul 21, 3:20 PM EDT | TSTM WND GST 55 | Fort Washington, PA | MESOWEST. |
| Jul 21, 3:25 PM EDT | HAIL 1 | Flourtown, PA | PHOTO FROM SOCIAL MEDIA, HAIL ESTIMATED AT QUARTER SIZE IN FLOURTOWN. TIME ESTIMATED FROM RADAR. |
| Jul 21, 3:30 PM EDT | HAIL 1 | Glenside, PA |
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, 6.7 hours before the alert went out and 219 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
- 638 J/kg
- Mixed-layer CIN
- -61 J/kg
- Mixed-layer LCL
- 1275 m above ground
- 0-6 km bulk shear
- 32 kt
- 0-1 km storm-relative helicity
- -12 m²/s²
- 0-3 km storm-relative helicity
- 95 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted.
607
WWUS81 KPHI 211841
SPSPHI
Special Weather Statement
National Weather Service Mount Holly NJ
241 PM EDT Wed Jul 21 2021
PAZ060-070-071-101>104-211930-
Eastern Montgomery-Western Montgomery-Delaware-Western
Chester-Eastern Chester-Berks-Philadelphia-
241 PM EDT Wed Jul 21 2021
...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT SOUTHEASTERN BERKS...
MONTGOMERY...NORTHEASTERN CHESTER...NORTHWESTERN PHILADELPHIA AND
NORTHEASTERN DELAWARE COUNTIES...
At 241 PM EDT, strong thunderstorms were clustered over Pottstown, or
18 miles east of Reading, moving southeast at 30 mph.
Wind gusts up to 40 mph and half inch hail are possible with this
storm.
Locations impacted include...
Philadelphia, Norristown, Pottstown, Phoenixville, Lansdale, West
Norriton, East Norriton, Conshohocken, Hatboro, Souderton, Ambler,
Swarthmore, Birdsboro, Collegeville, Royersford, Narberth, Trappe,
Hatfield, Schwenksville and Bryn Athyn.
This includes the following highways...
Pennsylvania Turnpike between mile markers 301 and 306, and between
mile markers 311 and 345.
Northeast Extension between mile markers 21 and 36.
Interstate 76 in Pennsylvania between mile markers 327 and 338.
Interstate 476 in Pennsylvania between mile markers 3 and 19.
Interstate 176 in Pennsylvania between mile markers 3 and 5.
LAT...LON 4043 7559 4022 7515 4017 7507 3990 7535
4020 7594
TIME...MOT...LOC 1841Z 304DEG 27KT 4024 7559
$$
NCThe office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 21, 11:09 AM EDT | Special Weather Statement | PHI | Morris | 36 min |
| Jul 21, 12:41 PM EDT | Special Weather Statement | PHI | Ocean | 34 min |
| Jul 21, 12:46 PM EDT | Special Marine Warning | PHI | 89 min | |
| Jul 21, 12:51 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Ocean | 39 min |
| Jul 21, 12:53 PM EDT | Severe Thunderstorm Warning | PHI | Ocean | 67 min |
| Jul 21, 1:28 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic | 47 min |
| Jul 21, 1:43 PM EDT | Severe Thunderstorm Warning | PHI | Ocean | 49 min |
| Jul 21, 2:10 PM EDT | Special Marine Warning | PHI | 95 min | |
| Jul 21, 2:13 PM EDT | Severe Thunderstorm Warning | PHI | Burlington | 47 min |
| Jul 21, 2:35 PM EDT | Special Marine Warning | PHI | 55 min | |
| Jul 21, 2:52 PM EDT | Severe Thunderstorm Warning | PHI | Ocean | 26 min |
| Jul 21, 3:04 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Camden, Gloucester | 56 min |
| Jul 21, 3:16 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Camden | 44 min |
| Jul 21, 3:27 PM EDT | Severe Thunderstorm Warning | PHI | Camden, Gloucester | 33 min |
| Jul 21, 3:43 PM EDT | Severe Thunderstorm Warning | PHI | Monmouth, Ocean | 47 min |
| Jul 21, 3:48 PM EDT | Special Marine Warning | PHI | 57 min | |
| Jul 21, 3:48 PM EDT | Severe Thunderstorm Warning | PHI | Burlington, Camden | 42 min |
| Jul 21, 3:57 PM EDT | Severe Thunderstorm Warning | PHI | Atlantic, Burlington, Camden, Gloucester, Salem | 33 min |
| Jul 21, 4:04 PM EDT | Special Marine Warning | PHI | 56 min | |
| Jul 21, 4:17 PM EDT | Special Marine Warning | PHI | 58 min | |
| Jul 21, 4:50 PM EDT | Special Marine Warning | PHI | 55 min | |
| Jul 21, 5:07 PM EDT | Special Marine Warning | PHI | 23 min | |
| Jul 21, 5:09 PM EDT | Special Marine Warning | PHI | 66 min | |
| Jul 21, 5:24 PM EDT | Special Marine Warning | PHI | 46 min | |
| Jul 21, 5:31 PM EDT | Severe Thunderstorm Warning | PHI | Cape May | 29 min |
| Jul 21, 5:52 PM EDT | Special Marine Warning | PHI | 53 min | |
| Jul 21, 1:08 PM EDT | Special Weather Statement | PHI | Lehigh | 37 min |
| Jul 21, 1:11 PM EDT | Special Weather Statement | PHI | Northampton | 34 min |
| Jul 21, 1:27 PM EDT | Severe Thunderstorm Warning | PHI | Berks | 48 min |
| Jul 21, 2:03 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Lehigh, Northampton | 42 min |
| Jul 21, 2:14 PM EDT | Severe Thunderstorm Warning | PHI | Berks, Bucks, Chester, Delaware, Montgomery | 19 min |
| Jul 21, 2:48 PM EDT | Severe Thunderstorm Warning | PHI | Bucks, Montgomery, Philadelphia | 42 min |
| Jul 21, 2:52 PM EDT | Severe Thunderstorm Warning | PHI | Chester, Delaware | 38 min |
| Jul 21, 5:59 PM EDT | Special Weather Statement | PHI | Berks | 31 min |
| Jul 21, 4:50 PM EDT | Severe Thunderstorm Warning | PHI | Kent, Sussex | 25 min |
| Jul 21, 3:48 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Queen Anne's, Talbot | 26 min |
| Jul 21, 4:16 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Queen Anne's | 44 min |
| Jul 21, 4:25 PM EDT | Severe Thunderstorm Warning | PHI | Caroline, Queen Anne's, Talbot | 30 min |
Nearby
Special Weather Statements in Pennsylvania, 2021Every special weather statement 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.