Alert archive / Pennsylvania / Jefferson County
Weather alerts in Jefferson County, Pennsylvania, 2020
113 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
Jefferson County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 113
- Warnings
- 26
- Watches
- 12
- Advisories
- 18
- Busiest month
- March16 alerts
- Busiest day
- June 22, 20208 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
Jefferson County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 12 | 11 | 8% | 21 | 71% | 16 min |
| Flash flood warnings | 1 | 1 | 0% | 0 |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS Pittsburgh, PA: tornado warnings | 10 | 3 | 70% | 8 | 38% | 4 min |
| NWS Pittsburgh, PA: severe thunderstorm warnings | 213 | 143 | 33% | 555 | 83% | 19 min |
| NWS Pittsburgh, PA: flash flood warnings | 24 | 19 | 21% | 49 | 90% | 83 min |
An office's figures cover every county it serves, including across state lines.
Verified by the Iowa Environmental Mesonet's Cow, which matches each storm-based warning with the local storm reports inside its polygon while it was in force, within 15 km of its edge: a tornado warning counts as verified on a tornado report, a severe thunderstorm warning on hail of 1 inch or more, a gust of 58 mph or more, or wind damage, a flash flood warning on a flash flood report. The false alarm ratio is the share of warnings with no such report; "inside a warning" is the probability of detection, the share of reports that fell inside one; lead time runs from the warning's issue to each report inside it, counting zero for a report that came first. A warning with no report is not proof nothing happened: reports come from spotters, the public and damage surveys, and are thin where few people live.
The alerts
Every alert, in the order issued. Times are local, Eastern Time. Each opens its own page with the text, the map, the radar and the sounding.
| Issued | Product | Office | Lasted |
|---|---|---|---|
| Jan 8, 3:11 AM EST | Special Weather Statement | PBZ | 79 min |
| Jan 8, 4:30 AM EST | Special Weather Statement | PBZ | 75 min |
| Jan 8, 6:21 AM EST | Special Weather Statement | PBZ | 24 min |
| Jan 8, 6:32 AM EST | Special Weather Statement | PBZ | 28 min |
| Jan 8, 7:18 AM EST | Special Weather Statement | PBZ | 57 min |
| Jan 8, 8:16 AM EST | Special Weather Statement | PBZ | 59 min |
| Jan 8, 9:21 AM EST | Snow Squall Warning | PBZ | 39 min |
| Jan 11, 3:15 AM EST | Wind Advisory | PBZ | 31 hr |
| Jan 16, 3:41 PM EST | Special Weather Statement | PBZ | 64 min |
| Jan 16, 4:50 PM EST | Special Weather Statement | PBZ | 55 min |
| Jan 16, 5:55 PM EST | Special Weather Statement | PBZ | 65 min |
| Jan 17, 2:02 PM EST | Winter Weather Advisory | PBZ | 28 hr |
| Feb 5, 3:44 AM EST | Winter Weather Advisory | PBZ | 27 hr |
| Feb 6, 2:58 PM EST | Winter Weather Advisory | PBZ | 28 hr |
| Feb 7, 5:32 AM EST | Mesoscale Discussion | SPC | 3 hr |
| Feb 8, 1:00 AM EST | Special Weather Statement | PBZ | 60 min |
| Feb 12, 10:26 AM EST | Winter Weather Advisory | PBZ | 24 hr |
| Feb 13, 9:00 PM EST | Special Weather Statement | PBZ | 60 min |
| Feb 13, 9:49 PM EST | Special Weather Statement | PBZ | 86 min |
| Feb 29, 9:35 AM EST | Special Weather Statement | PBZ | 40 min |
| Feb 29, 10:16 AM EST | Special Weather Statement | PBZ | 74 min |
| Mar 3, 4:27 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Mar 3, 9:20 PM EST | Special Weather Statement | PBZ | 25 min |
| Mar 20, 12:21 PM EDT | Special Weather Statement | PBZ | 54 min |
| Mar 20, 12:40 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Mar 20, 1:25 PM EDT | Severe Thunderstorm Warning | PBZ | 38 min |
| Mar 20, 1:29 PM EDT | Special Weather Statement | PBZ | 46 min |
| Mar 20, 2:15 PM EDT | Severe Thunderstorm Warning | PBZ | 45 min |
| Mar 20, 2:33 PM EDT | Areal Flood Warning | PBZ | 3 hr |
| Mar 28, 1:42 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Mar 28, 3:06 PM EDT | Severe Thunderstorm Warning | PBZ | 24 min |
| Mar 28, 4:25 PM EDT | Severe Thunderstorm Warning | PBZ | 50 min |
| Mar 28, 4:35 PM EDT | Flash Flood Warning | PBZ | 5 hr |
| Mar 28, 9:13 PM EDT | Areal Flood Warning | PBZ | 6 hr |
| Mar 29, 10:58 AM EDT | Mesoscale Discussion | SPC | 2 hr |
| Mar 29, 12:05 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Mar 29, 1:58 PM EDT | Wind Advisory | PBZ | 7 hr |
| Apr 7, 10:54 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Apr 7, 11:32 PM EDT | Special Weather Statement | PBZ | 28 min |
| Apr 7, 11:40 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Apr 8, 12:04 AM EDT | Special Weather Statement | PBZ | 26 min |
| Apr 11, 2:03 PM EDT | High Wind Watch | PBZ | 24 hr |
| Apr 12, 1:44 PM EDT | High Wind Warning | PBZ | 30 hr |
| May 4, 1:18 PM EDT | Frost Advisory | PBZ | 19 hr |
| May 4, 1:18 PM EDT | Freeze Warning | PBZ | 19 hr |
| May 6, 1:01 PM EDT | Freeze Warning | PBZ | 20 hr |
| May 7, 1:13 PM EDT | Freeze Warning | PBZ | 18 hr |
| May 7, 1:13 PM EDT | Freeze Warning | PBZ | 45 hr |
| May 9, 3:17 AM EDT | Freeze Warning | PBZ | 28 hr |
| May 10, 8:19 PM EDT | Special Weather Statement | PBZ | 56 min |
| May 11, 2:53 AM EDT | Freeze Warning | PBZ | 29 hr |
| May 12, 11:46 AM EDT | Freeze Warning | PBZ | 21 hr |
| May 15, 1:52 PM EDT | Mesoscale Discussion | SPC | 83 min |
| May 15, 7:47 PM EDT | Mesoscale Discussion | SPC | 58 min |
| May 23, 3:51 AM EDT | Dense Fog Advisory | PBZ | 5 hr |
| May 29, 10:47 AM EDT | Mesoscale Discussion | SPC | 118 min |
| May 29, 4:54 PM EDT | Severe Thunderstorm Warning | PBZ | 51 min |
| May 29, 4:54 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| May 29, 5:36 PM EDT | Special Weather Statement | PBZ | 24 min |
| Jun 3, 8:32 AM EDT | Mesoscale Discussion | SPC | 118 min |
| Jun 3, 8:54 AM EDT | Severe Thunderstorm Warning | PBZ | 40 min |
| Jun 3, 9:26 AM EDT | Severe Thunderstorm Warning | PBZ | 49 min |
| Jun 3, 3:10 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 4, 12:55 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 4, 5:44 PM EDT | Special Weather Statement | PBZ | 76 min |
| Jun 10, 6:51 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 19, 2:08 PM EDT | Special Weather Statement | PBZ | 22 min |
| Jun 22, 1:58 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 22, 2:19 PM EDT | Special Weather Statement | PBZ | 41 min |
| Jun 22, 2:24 PM EDT | Severe Thunderstorm Warning | PBZ | 51 min |
| Jun 22, 2:35 PM EDT | Areal Flood Advisory | PBZ | 2 hr |
| Jun 22, 2:51 PM EDT | Special Weather Statement | CTP | 24 min |
| Jun 22, 2:54 PM EDT | Special Weather Statement | PBZ | 36 min |
| Jun 22, 3:06 PM EDT | Special Weather Statement | PBZ | 54 min |
| Jun 22, 3:29 PM EDT | Special Weather Statement | PBZ | 31 min |
| Jul 7, 7:31 PM EDT | Special Weather Statement | PBZ | 14 min |
| Jul 7, 7:53 PM EDT | Special Weather Statement | PBZ | 22 min |
| Jul 7, 8:56 PM EDT | Areal Flood Advisory | PBZ | 2 hr |
| Jul 16, 12:18 PM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 16, 1:20 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jul 16, 3:51 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Jul 16, 7:51 PM EDT | Mesoscale Discussion | SPC | 54 min |
| Jul 19, 7:44 PM EDT | Special Weather Statement | PBZ | 46 min |
| Jul 19, 8:28 PM EDT | Special Weather Statement | PBZ | 32 min |
| Jul 29, 1:36 PM EDT | Mesoscale Discussion | SPC | 84 min |
| Jul 30, 5:23 PM EDT | Special Weather Statement | PBZ | 37 min |
| Aug 24, 2:02 PM EDT | Special Weather Statement | PBZ | 28 min |
| Aug 24, 3:03 PM EDT | Special Weather Statement | PBZ | |
| Aug 25, 12:02 PM EDT | Mesoscale Discussion | SPC | 118 min |
| Aug 25, 1:21 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 27, 4:34 PM EDT | Mesoscale Discussion | SPC | 86 min |
| Aug 27, 5:32 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 27, 5:40 PM EDT | Severe Thunderstorm Warning | PBZ | 50 min |
| Aug 28, 9:55 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 28, 10:27 AM EDT | Severe Thunderstorm Warning | PBZ | 48 min |
| Aug 28, 11:35 AM EDT | Special Weather Statement | PBZ | 25 min |
| Sep 18, 9:12 AM EDT | Frost Advisory | PBZ | 24 hr |
| Sep 19, 1:17 PM EDT | Frost Advisory | PBZ | 20 hr |
| Sep 20, 12:12 PM EDT | Frost Advisory | PBZ | 21 hr |
| Sep 21, 3:35 PM EDT | Frost Advisory | PBZ | 17 hr |
| Oct 2, 1:10 PM EDT | Frost Advisory | PBZ | 20 hr |
| Oct 15, 5:04 PM EDT | Freeze Watch | PBZ | 21 hr |
| Nov 14, 1:10 PM EST | Wind Advisory | PBZ | 42 hr |
| Nov 15, 1:16 PM EST | Mesoscale Discussion | SPC | 89 min |
| Nov 15, 1:57 PM EST | Severe Thunderstorm Watch | SPC | 4 hr |
| Nov 15, 3:13 PM EST | Severe Thunderstorm Warning | PBZ | 47 min |
| Nov 15, 3:39 PM EST | Severe Thunderstorm Warning | PBZ | 24 min |
| Nov 29, 7:35 PM EST | Winter Weather Advisory | PBZ | 56 hr |
| Nov 30, 3:18 AM EST | Winter Storm Warning | PBZ | 48 hr |
| Dec 15, 3:46 AM EST | Winter Storm Watch | PBZ | 9 hr |
| Dec 15, 3:46 AM EST | Winter Storm Warning | PBZ | 49 hr |
| Dec 16, 5:41 PM EST | Special Weather Statement | PBZ | 2 hr |
| Dec 23, 12:39 PM EST | Winter Weather Advisory | PBZ | 48 hr |
By product
Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.
| Product | Alerts |
|---|---|
| Severe storms | |
| Severe Thunderstorm Warning | 12 |
| Severe Thunderstorm Watch | 9 |
| Mesoscale Discussion | 20 |
| Special Weather Statement | 37 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 1 |
| Areal Flood Advisory | 2 |
| Winter | |
| Snow Squall Warning | 1 |
| Winter Storm Warning | 2 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 6 |
| Cold | |
| Freeze Warning | 7 |
| Freeze Watch | 1 |
| Frost Advisory | 6 |
| Wind and dust | |
| High Wind Warning | 1 |
| High Wind Watch | 1 |
| Wind Advisory | 3 |
| Fog and smoke | |
| Dense Fog Advisory | 1 |
The busiest days
Days with the most alerts issued, by UTC date.
Nearby
Alerts in force nowTornadoes on recordForecastThe radar archive20192021
Sources
National Weather Service watches, warnings, advisories and statements from the Iowa Environmental Mesonet's VTEC archive, which reconstructs tornado, severe thunderstorm, flash flood and marine warnings back to 1986 from the NWS text archive. Storm Prediction Center watches and mesoscale discussions from SPC's archive through the Mesonet. County centers from the US Census Bureau. Warning verification from the Mesonet's Cow. Rebuilt daily.