Alert archive / Pennsylvania / York County
Weather alerts in York County, Pennsylvania, 2020
184 weather alerts in 2020, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.
York County and its neighbors
Each county as a circle sized by its count in 2020. Tap one for its archive.
- Alerts
- 184
- Warnings
- 45
- Watches
- 27
- Advisories
- 46
- Busiest month
- August31 alerts
- Busiest day
- June 4, 202010 alerts
Over time
By month
Warning verification
How often warnings here had a storm report inside them, and how much warning the reports had.
York County, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| Tornado warnings | 0 | 0 | ||||
| Severe thunderstorm warnings | 25 | 24 | 4% | 47 | 94% | 25 min |
| Flash flood warnings | 5 | 4 | 20% | 3 | 100% | 51 min |
Each office's whole area, 2020
| Warnings | With a report | False alarm ratio | Reports | Inside a warning | Mean lead time | |
|---|---|---|---|---|---|---|
| NWS State College, PA: tornado warnings | 3 | 0 | 100% | 0 | ||
| NWS State College, PA: severe thunderstorm warnings | 163 | 128 | 21% | 422 | 76% | 23 min |
| NWS State College, PA: flash flood warnings | 10 | 6 | 40% | 25 | 92% | 57 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 7, 2:01 AM EST | Winter Weather Advisory | CTP | 17 hr |
| Jan 7, 12:29 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Jan 8, 7:24 AM EST | Snow Squall Warning | CTP | 51 min |
| Jan 8, 8:14 AM EST | Snow Squall Warning | CTP | 46 min |
| Jan 11, 4:07 AM EST | Wind Advisory | CTP | 30 hr |
| Jan 11, 11:51 PM EST | Special Weather Statement | CTP | 54 min |
| Jan 12, 12:34 AM EST | Special Weather Statement | CTP | 56 min |
| Jan 15, 2:23 PM EST | Wind Advisory | CTP | 29 hr |
| Jan 17, 3:01 PM EST | Winter Weather Advisory | CTP | 30 hr |
| Jan 18, 11:53 AM EST | Special Weather Statement | CTP | 82 min |
| Feb 1, 1:22 AM EST | Dense Fog Advisory | CTP | 7 hr |
| Feb 6, 10:49 PM EST | Wind Advisory | CTP | 18 hr |
| Feb 7, 8:09 AM EST | Special Weather Statement | CTP | 51 min |
| Feb 7, 8:17 AM EST | Severe Thunderstorm Warning | CTP | 28 min |
| Feb 7, 8:42 AM EST | Severe Thunderstorm Warning | CTP | 48 min |
| Feb 26, 3:40 AM EST | Wind Advisory | CTP | 40 hr |
| Mar 3, 6:50 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Mar 3, 8:09 PM EST | Special Weather Statement | CTP | 36 min |
| Mar 3, 10:52 PM EST | Mesoscale Discussion | SPC | 113 min |
| Mar 3, 10:57 PM EST | Special Weather Statement | CTP | 48 min |
| Mar 20, 3:00 AM EDT | Dense Fog Advisory | CTP | 5 hr |
| Apr 8, 8:43 PM EDT | Wind Advisory | CTP | 21 hr |
| Apr 9, 11:28 AM EDT | Special Weather Statement | CTP | 47 min |
| Apr 9, 1:00 PM EDT | Special Weather Statement | CTP | 30 min |
| Apr 9, 11:18 PM EDT | Severe Thunderstorm Warning | CTP | 42 min |
| Apr 10, 2:15 AM EDT | Freeze Watch | CTP | 11 hr |
| Apr 10, 2:15 AM EDT | Wind Advisory | CTP | 17 hr |
| Apr 10, 1:21 PM EDT | Freeze Warning | CTP | 19 hr |
| Apr 12, 12:43 PM EDT | Wind Advisory | CTP | 31 hr |
| Apr 13, 7:32 AM EDT | Special Weather Statement | CTP | 43 min |
| Apr 13, 10:34 AM EDT | Mesoscale Discussion | SPC | 86 min |
| Apr 13, 11:33 AM EDT | Tornado Watch | SPC | 5 hr |
| Apr 13, 12:52 PM EDT | Severe Thunderstorm Warning | CTP | 38 min |
| Apr 13, 1:20 PM EDT | Mesoscale Discussion | SPC | 85 min |
| Apr 13, 1:37 PM EDT | Severe Thunderstorm Warning | CTP | 68 min |
| Apr 13, 2:09 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Apr 16, 4:56 AM EDT | Freeze Watch | CTP | 9 hr |
| Apr 16, 2:05 PM EDT | Freeze Warning | CTP | 19 hr |
| Apr 18, 3:34 AM EDT | Frost Advisory | CTP | 29 hr |
| Apr 21, 4:18 AM EDT | Freeze Warning | CTP | 29 hr |
| Apr 21, 12:06 PM EDT | Special Weather Statement | CTP | 69 min |
| Apr 25, 3:32 AM EDT | Dense Fog Advisory | CTP | 4 hr |
| Apr 29, 3:33 AM EDT | Flood Watch | CTP | 50 hr |
| Apr 30, 10:59 AM EDT | Areal Flood Advisory | CTP | 6 hr |
| Apr 30, 1:22 PM EDT | Special Weather Statement | CTP | 113 min |
| Apr 30, 1:34 PM EDT | Areal Flood Advisory | CTP | 6 hr |
| Apr 30, 2:12 PM EDT | Areal Flood Warning | CTP | 6 hr |
| Apr 30, 4:39 PM EDT | Areal Flood Warning | CTP | 6 hr |
| Apr 30, 8:06 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| May 1, 1:52 PM EDT | River Flood Warning | CTP | 9 hr |
| May 7, 1:44 PM EDT | Freeze Watch | CTP | 13 hr |
| May 7, 1:44 PM EDT | Freeze Warning | CTP | 44 hr |
| May 9, 5:04 AM EDT | Freeze Warning | CTP | 27 hr |
| May 11, 2:58 AM EDT | Frost Advisory | CTP | 27 hr |
| May 12, 2:25 PM EDT | Frost Advisory | CTP | 18 hr |
| May 29, 12:27 PM EDT | Mesoscale Discussion | SPC | 63 min |
| May 29, 1:58 PM EDT | Severe Thunderstorm Warning | CTP | 47 min |
| May 29, 2:25 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| May 29, 2:44 PM EDT | Severe Thunderstorm Warning | CTP | 46 min |
| May 29, 3:03 PM EDT | Mesoscale Discussion | SPC | 87 min |
| May 29, 3:43 PM EDT | Special Weather Statement | CTP | 32 min |
| May 29, 8:01 PM EDT | Mesoscale Discussion | SPC | 119 min |
| Jun 3, 8:32 AM EDT | Mesoscale Discussion | SPC | 118 min |
| Jun 3, 10:08 AM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Jun 3, 11:19 AM EDT | Severe Thunderstorm Warning | CTP | 56 min |
| Jun 3, 11:34 AM EDT | Mesoscale Discussion | SPC | 86 min |
| Jun 3, 3:10 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jun 3, 3:52 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Jun 3, 7:27 PM EDT | Severe Thunderstorm Warning | CTP | 63 min |
| Jun 3, 7:44 PM EDT | Mesoscale Discussion | SPC | 91 min |
| Jun 3, 8:15 PM EDT | Severe Thunderstorm Warning | CTP | 45 min |
| Jun 3, 8:52 PM EDT | Severe Thunderstorm Warning | CTP | 23 min |
| Jun 4, 2:02 PM EDT | Mesoscale Discussion | SPC | 118 min |
| Jun 4, 2:29 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Jun 4, 4:41 PM EDT | Mesoscale Discussion | SPC | 94 min |
| Jun 4, 6:31 PM EDT | Severe Thunderstorm Warning | CTP | 59 min |
| Jun 4, 6:44 PM EDT | Mesoscale Discussion | SPC | 91 min |
| Jun 4, 7:17 PM EDT | Severe Thunderstorm Warning | CTP | 58 min |
| Jun 4, 7:30 PM EDT | Special Weather Statement | CTP | 30 min |
| Jun 4, 7:59 PM EDT | Severe Thunderstorm Warning | CTP | 61 min |
| Jun 4, 8:54 PM EDT | Areal Flood Advisory | CTP | 111 min |
| Jun 5, 10:38 AM EDT | Flash Flood Watch | CTP | 10 hr |
| Jun 5, 2:01 PM EDT | Special Weather Statement | CTP | 59 min |
| Jun 5, 4:10 PM EDT | Special Weather Statement | CTP | 35 min |
| Jun 5, 4:46 PM EDT | Areal Flood Advisory | CTP | 119 min |
| Jun 5, 5:39 PM EDT | Areal Flood Advisory | CTP | 111 min |
| Jun 10, 10:39 PM EDT | Special Weather Statement | CTP | 36 min |
| Jun 22, 1:58 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jun 22, 5:16 PM EDT | Special Weather Statement | CTP | 44 min |
| Jun 23, 6:51 PM EDT | Special Weather Statement | CTP | 24 min |
| Jun 25, 4:24 PM EDT | Special Weather Statement | CTP | 36 min |
| Jul 6, 12:33 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Jul 6, 1:38 PM EDT | Severe Thunderstorm Watch | SPC | 9 hr |
| Jul 6, 4:33 PM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 6, 8:29 PM EDT | Special Weather Statement | CTP | 46 min |
| Jul 6, 8:39 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Jul 6, 8:56 PM EDT | Severe Thunderstorm Warning | CTP | 49 min |
| Jul 8, 5:48 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Jul 8, 5:52 PM EDT | Flash Flood Warning | CTP | 3 hr |
| Jul 8, 6:01 PM EDT | Severe Thunderstorm Warning | CTP | 44 min |
| Jul 8, 6:33 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Jul 18, 2:29 PM EDT | Heat Advisory | CTP | 54 hr |
| Jul 21, 2:01 PM EDT | Mesoscale Discussion | SPC | 59 min |
| Jul 21, 6:24 PM EDT | Special Weather Statement | CTP | 21 min |
| Jul 21, 6:36 PM EDT | Areal Flood Advisory | CTP | 54 min |
| Jul 21, 6:43 PM EDT | Severe Thunderstorm Warning | CTP | 32 min |
| Jul 21, 7:28 PM EDT | Areal Flood Advisory | CTP | 2 hr |
| Jul 22, 3:13 AM EDT | Heat Advisory | CTP | 17 hr |
| Jul 22, 10:48 AM EDT | Mesoscale Discussion | SPC | 117 min |
| Jul 22, 12:01 PM EDT | Severe Thunderstorm Watch | SPC | 7 hr |
| Jul 22, 1:38 PM EDT | Severe Thunderstorm Warning | CTP | 67 min |
| Jul 22, 3:03 PM EDT | Special Weather Statement | CTP | 42 min |
| Jul 22, 3:12 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Jul 22, 3:39 PM EDT | Severe Thunderstorm Warning | CTP | 36 min |
| Jul 22, 3:53 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Jul 22, 4:00 PM EDT | Special Weather Statement | CTP | 30 min |
| Jul 23, 8:05 PM EDT | Special Weather Statement | CTP | 40 min |
| Jul 24, 5:24 PM EDT | Areal Flood Advisory | CTP | 111 min |
| Aug 2, 12:58 AM EDT | Special Weather Statement | CTP | 62 min |
| Aug 2, 2:52 AM EDT | Areal Flood Advisory | CTP | 3 hr |
| Aug 2, 3:59 PM EDT | Flash Flood Watch | CTP | 47 hr |
| Aug 4, 8:55 AM EDT | River Flood Warning | CTP | 7 hr |
| Aug 4, 9:37 AM EDT | Areal Flood Advisory | CTP | 4 hr |
| Aug 4, 10:30 AM EDT | Flash Flood Warning | CTP | 4 hr |
| Aug 6, 1:59 PM EDT | Flash Flood Watch | CTP | 8 hr |
| Aug 6, 7:32 PM EDT | Special Weather Statement | CTP | 43 min |
| Aug 7, 10:06 AM EDT | Flash Flood Watch | CTP | 9 hr |
| Aug 7, 1:30 PM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 7, 3:14 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Aug 7, 3:31 PM EDT | Flash Flood Warning | CTP | 3 hr |
| Aug 7, 4:40 PM EDT | Flash Flood Warning | CTP | 118 min |
| Aug 12, 3:09 AM EDT | Flash Flood Watch | CTP | 16 hr |
| Aug 12, 1:15 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 12, 3:42 PM EDT | Areal Flood Advisory | CTP | 3 hr |
| Aug 12, 4:15 PM EDT | Flash Flood Warning | CTP | 2 hr |
| Aug 13, 2:22 AM EDT | Flash Flood Watch | CTP | 18 hr |
| Aug 23, 3:57 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 24, 12:44 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 25, 1:21 PM EDT | Severe Thunderstorm Watch | SPC | 6 hr |
| Aug 25, 3:10 PM EDT | Mesoscale Discussion | SPC | 95 min |
| Aug 27, 5:32 PM EDT | Severe Thunderstorm Watch | SPC | 4 hr |
| Aug 27, 6:35 PM EDT | Mesoscale Discussion | SPC | 115 min |
| Aug 28, 9:55 AM EDT | Mesoscale Discussion | SPC | 3 hr |
| Aug 28, 1:37 PM EDT | Severe Thunderstorm Watch | SPC | 8 hr |
| Aug 28, 2:16 PM EDT | Severe Thunderstorm Warning | CTP | 59 min |
| Aug 28, 3:00 PM EDT | Severe Thunderstorm Warning | CTP | 60 min |
| Aug 28, 3:35 PM EDT | Severe Thunderstorm Warning | CTP | 54 min |
| Aug 29, 3:56 PM EDT | Mesoscale Discussion | SPC | 2 hr |
| Aug 29, 6:44 PM EDT | Special Weather Statement | CTP | 61 min |
| Sep 2, 3:37 PM EDT | Mesoscale Discussion | SPC | 53 min |
| Sep 2, 6:43 PM EDT | Severe Thunderstorm Watch | SPC | 5 hr |
| Sep 2, 7:18 PM EDT | Special Weather Statement | CTP | 27 min |
| Sep 3, 3:06 PM EDT | Mesoscale Discussion | SPC | 114 min |
| Sep 3, 3:42 PM EDT | Tornado Watch | SPC | 6 hr |
| Sep 3, 5:11 PM EDT | Special Weather Statement | CTP | 34 min |
| Sep 3, 5:30 PM EDT | Severe Thunderstorm Warning | CTP | 30 min |
| Sep 10, 1:38 PM EDT | Flash Flood Watch | CTP | 6 hr |
| Sep 10, 1:56 PM EDT | Areal Flood Advisory | CTP | 2 hr |
| Sep 10, 4:02 PM EDT | Areal Flood Advisory | CTP | 118 min |
| Sep 19, 12:53 PM EDT | Frost Advisory | CTP | 20 hr |
| Sep 20, 11:59 AM EDT | Frost Advisory | CTP | 21 hr |
| Sep 21, 1:35 PM EDT | Frost Advisory | CTP | 19 hr |
| Oct 16, 2:44 PM EDT | Frost Advisory | CTP | 17 hr |
| Oct 17, 12:25 PM EDT | Frost Advisory | CTP | 21 hr |
| Oct 22, 3:58 AM EDT | Dense Fog Advisory | CTP | 6 hr |
| Oct 29, 2:15 AM EDT | Freeze Watch | CTP | 12 hr |
| Oct 29, 2:04 PM EDT | Freeze Warning | CTP | 43 hr |
| Nov 1, 9:59 PM EST | Wind Advisory | CTP | 14 hr |
| Nov 14, 2:11 PM EST | Wind Advisory | CTP | 32 hr |
| Nov 15, 3:33 PM EST | Mesoscale Discussion | SPC | 2 hr |
| Nov 15, 4:55 PM EST | Severe Thunderstorm Warning | CTP | 80 min |
| Nov 15, 5:35 PM EST | Severe Thunderstorm Watch | SPC | 5 hr |
| Nov 15, 5:51 PM EST | Severe Thunderstorm Warning | CTP | 84 min |
| Nov 15, 6:52 PM EST | Mesoscale Discussion | SPC | 113 min |
| Dec 12, 7:36 AM EST | Special Weather Statement | CTP | 84 min |
| Dec 13, 1:37 PM EST | Winter Weather Advisory | CTP | 25 hr |
| Dec 14, 4:44 AM EST | Winter Storm Watch | CTP | 34 hr |
| Dec 15, 4:30 AM EST | Winter Storm Warning | CTP | 51 hr |
| Dec 16, 1:57 PM EST | Mesoscale Discussion | SPC | 5 hr |
| Dec 16, 4:41 PM EST | Special Weather Statement | CTP | 49 min |
| Dec 22, 3:09 PM EST | Flood Watch | CTP | 69 hr |
| Dec 25, 12:08 AM EST | Special Weather Statement | CTP | 67 min |
| Dec 25, 12:31 PM EST | River Flood Warning | CTP | 45 hr |
| Dec 25, 12:31 PM EST | River Flood Warning | CTP | 36 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 | 25 |
| Severe Thunderstorm Watch | 11 |
| Tornado Watch | 2 |
| Mesoscale Discussion | 34 |
| Special Weather Statement | 32 |
| Flooding | |
| Areal Flood Warning | 2 |
| Flash Flood Warning | 5 |
| River Flood Warning | 4 |
| Flash Flood Watch | 7 |
| Flood Watch | 2 |
| Areal Flood Advisory | 20 |
| Winter | |
| Snow Squall Warning | 2 |
| Winter Storm Warning | 1 |
| Winter Storm Watch | 1 |
| Winter Weather Advisory | 3 |
| Heat | |
| Heat Advisory | 2 |
| Cold | |
| Freeze Warning | 6 |
| Freeze Watch | 4 |
| Frost Advisory | 8 |
| Wind and dust | |
| Wind Advisory | 9 |
| Fog and smoke | |
| Dense Fog Advisory | 4 |
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.