Alert archive / Pennsylvania / Philadelphia County

Weather alerts in Philadelphia County, Pennsylvania, 2012

245 weather alerts in 2012, from the National Weather Service and the Storm Prediction Center. An alert counts here when it covered this county.

Philadelphia County and its neighbors

Each county as a circle sized by its count in 2012. Tap one for its archive.

Alerts
245
Warnings
51
Watches
37
Advisories
63
Busiest month
June40 alerts
Busiest day
September 18, 201210 alerts

Over time

By month

Warning verification

How often warnings here had a storm report inside them, and how much warning the reports had.

Philadelphia County, 2012

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
Tornado warnings00
Severe thunderstorm warnings181517%3100%17 min
Flash flood warnings4250%1100%36 min

Each office's whole area, 2012

WarningsWith a reportFalse alarm ratioReportsInside a warningMean lead time
NWS Philadelphia/Mount Holly: tornado warnings8188%333%1 min
NWS Philadelphia/Mount Holly: severe thunderstorm warnings23815933%41090%28 min
NWS Philadelphia/Mount Holly: flash flood warnings572556%4973%55 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.

IssuedProductOfficeLasted
Jan 11, 3:44 AM ESTWinter Weather AdvisoryPHI31 days
Jan 12, 1:19 PM ESTCoastal Flood WarningPHI73 min
Jan 12, 9:27 PM ESTWind AdvisoryPHI20 hr
Jan 15, 3:51 AM ESTSpecial Weather StatementPHI54 min
Jan 15, 4:32 AM ESTSpecial Weather StatementPHI43 min
Jan 20, 3:46 AM ESTWinter Weather AdvisoryPHI41 days
Jan 21, 7:07 AM ESTMesoscale DiscussionSPC3 hr
Jan 27, 8:27 AM ESTSpecial Weather StatementPHI93 min
Jan 27, 2:15 PM ESTWind AdvisoryPHI6 hr
Feb 8, 12:12 PM ESTWinter Weather AdvisoryPHI274 days
Feb 11, 3:37 PM ESTWind AdvisoryPHI12 hr
Feb 11, 6:16 PM ESTSpecial Weather StatementPHI104 min
Feb 24, 3:40 AM ESTWind AdvisoryPHI42 hr
Feb 25, 10:35 AM ESTSpecial Weather StatementPHI55 min
Feb 29, 7:45 PM ESTSpecial Weather StatementPHI2 hr
Mar 3, 6:12 AM ESTDense Fog AdvisoryPHI3 hr
Mar 3, 4:15 PM ESTWind AdvisoryPHI2 hr
Mar 6, 2:37 PM ESTFire Weather WatchPHI13 hr
Mar 7, 3:31 AM ESTRed Flag WarningPHI12 hr
Mar 9, 12:01 AM ESTSpecial Weather StatementPHI59 min
Mar 9, 12:58 AM ESTSpecial Weather StatementPHI62 min
Mar 20, 2:02 AM EDTDense Fog AdvisoryPHI8 hr
Mar 21, 8:02 PM EDTDense Fog AdvisoryPHI14 hr
Mar 25, 3:28 PM EDTFreeze WatchPHI12 hr
Mar 26, 3:46 AM EDTFreeze WarningPHI29 hr
Apr 4, 11:00 AM EDTRed Flag WarningPHI9 hr
Apr 5, 3:15 PM EDTFire Weather WatchPHI11 hr
Apr 6, 2:40 AM EDTRed Flag WarningPHI17 hr
Apr 6, 3:10 PM EDTFire Weather WatchPHI13 hr
Apr 6, 7:56 PM EDTRed Flag WarningPHI24 hr
Apr 7, 3:49 AM EDTFire Weather WatchPHI18 hr
Apr 7, 8:14 PM EDTRed Flag WarningPHI24 hr
Apr 8, 4:07 AM EDTFire Weather WatchPHI16 hr
Apr 8, 8:01 PM EDTRed Flag WarningPHI24 hr
Apr 9, 4:03 AM EDTWind AdvisoryPHI14 hr
Apr 9, 3:12 PM EDTFire Weather WatchPHI13 hr
Apr 9, 8:04 PM EDTRed Flag WarningPHI24 hr
Apr 16, 3:47 PM EDTFire Weather WatchPHI12 hr
Apr 17, 3:28 AM EDTRed Flag WarningPHI17 hr
Apr 21, 3:15 PM EDTFlood WatchPHI36 hr
Apr 21, 8:41 PM EDTSpecial Weather StatementPHI109 min
Apr 21, 8:45 PM EDTSevere Thunderstorm WarningPHI30 min
Apr 21, 9:38 PM EDTSevere Thunderstorm WarningPHI67 min
Apr 22, 3:45 AM EDTWind AdvisoryPHI20 hr
Apr 22, 4:14 AM EDTCoastal Flood AdvisoryPHI20 hr
Apr 22, 9:00 PM EDTAreal Flood AdvisoryPHI6 hr
May 4, 1:26 PM EDTMesoscale DiscussionSPC2 hr
May 6, 3:47 AM EDTCoastal Flood AdvisoryPHI24 hr
May 7, 5:42 AM EDTCoastal Flood StatementPHI22 hr
May 15, 6:40 AM EDTSpecial Weather StatementPHI50 min
May 15, 7:30 AM EDTSpecial Weather StatementPHI2 hr
May 16, 12:20 AM EDTSpecial Weather StatementPHI55 min
May 16, 2:37 AM EDTAreal Flood WarningPHI3 hr
May 17, 9:55 PM EDTCoastal Flood StatementPHI108 min
May 24, 1:57 PM EDTSpecial Weather StatementPHI63 min
May 24, 2:01 PM EDTAreal Flood AdvisoryPHI83 min
May 26, 3:40 PM EDTExcessive Heat WatchPHI23 hr
May 27, 4:46 AM EDTSpecial Weather StatementPHI59 min
May 27, 4:58 AM EDTAreal Flood AdvisoryPHI83 min
May 27, 5:57 AM EDTFlash Flood WarningPHI2 hr
May 27, 10:07 AM EDTAreal Flood WarningPHI3 hr
May 27, 3:01 PM EDTExcessive Heat WarningPHI52 hr
May 29, 12:29 PM EDTFlash Flood WatchPHI8 hr
May 29, 2:13 PM EDTMesoscale DiscussionSPC62 min
May 29, 5:54 PM EDTSevere Thunderstorm WatchSPC3 hr
May 29, 6:46 PM EDTSpecial Weather StatementPHI89 min
May 29, 7:01 PM EDTMesoscale DiscussionSPC89 min
May 29, 7:34 PM EDTSpecial Weather StatementPHI56 min
May 29, 7:35 PM EDTAreal Flood AdvisoryPHI115 min
Jun 1, 6:20 AM EDTCoastal Flood AdvisoryPHI24 hr
Jun 1, 3:49 PM EDTMesoscale DiscussionSPC56 min
Jun 1, 4:15 PM EDTFlash Flood WatchPHI11 hr
Jun 1, 4:25 PM EDTMesoscale DiscussionSPC65 min
Jun 1, 8:01 PM EDTTornado WatchSPC4 hr
Jun 1, 8:46 PM EDTAreal Flood AdvisoryPHI5 hr
Jun 2, 11:28 AM EDTCoastal Flood AdvisoryPHI15 hr
Jun 3, 3:57 AM EDTCoastal Flood AdvisoryPHI23 hr
Jun 3, 1:32 PM EDTSpecial Weather StatementPHI118 min
Jun 3, 1:37 PM EDTMesoscale DiscussionSPC2 hr
Jun 3, 2:47 PM EDTSpecial Weather StatementPHI118 min
Jun 3, 7:20 PM EDTSpecial Weather StatementPHI85 min
Jun 3, 8:10 PM EDTSpecial Weather StatementPHI95 min
Jun 4, 4:24 AM EDTCoastal Flood AdvisoryPHI23 hr
Jun 5, 3:44 AM EDTCoastal Flood AdvisoryPHI31 hr
Jun 6, 5:11 AM EDTCoastal Flood StatementPHI6 hr
Jun 6, 10:51 AM EDTCoastal Flood AdvisoryPHI23 hr
Jun 7, 4:51 AM EDTCoastal Flood StatementPHI23 hr
Jun 12, 10:17 PM EDTAreal Flood AdvisoryPHI106 min
Jun 15, 9:26 PM EDTCoastal Flood StatementPHI6 hr
Jun 18, 3:19 AM EDTExcessive Heat WatchPHI12 hr
Jun 18, 3:26 PM EDTExcessive Heat WarningPHI4 days
Jun 22, 12:18 PM EDTMesoscale DiscussionSPC2 hr
Jun 22, 1:41 PM EDTSevere Thunderstorm WatchSPC7 hr
Jun 22, 4:33 PM EDTMesoscale DiscussionSPC87 min
Jun 22, 6:13 PM EDTSpecial Weather StatementPHI62 min
Jun 22, 6:16 PM EDTSpecial Weather StatementPHI119 min
Jun 22, 6:42 PM EDTMesoscale DiscussionSPC63 min
Jun 22, 7:02 PM EDTAreal Flood AdvisoryPHI102 min
Jun 22, 7:04 PM EDTSevere Thunderstorm WarningPHI56 min
Jun 25, 3:44 AM EDTMesoscale DiscussionSPC2 hr
Jun 25, 6:21 AM EDTMesoscale DiscussionSPC24 min
Jun 25, 6:39 AM EDTSevere Thunderstorm WatchSPC7 hr
Jun 26, 3:42 PM EDTExcessive Heat WatchPHI36 hr
Jun 28, 3:59 AM EDTExcessive Heat WarningPHI4 days
Jun 29, 3:41 AM EDTMesoscale DiscussionSPC94 min
Jun 29, 3:51 AM EDTSpecial Weather StatementPHI54 min
Jun 29, 4:34 AM EDTSevere Thunderstorm WatchSPC3 hr
Jun 29, 5:00 AM EDTSevere Thunderstorm WarningPHI75 min
Jun 29, 11:51 PM EDTSpecial Weather StatementPHI54 min
Jul 1, 12:11 PM EDTMesoscale DiscussionSPC64 min
Jul 3, 3:47 AM EDTExcessive Heat WatchPHI12 hr
Jul 3, 3:28 PM EDTExcessive Heat WarningPHI5 days
Jul 4, 3:39 AM EDTExcessive Heat WatchPHI12 hr
Jul 7, 11:19 AM EDTMesoscale DiscussionSPC86 min
Jul 7, 5:43 PM EDTMesoscale DiscussionSPC62 min
Jul 7, 5:57 PM EDTSevere Thunderstorm WarningPHI63 min
Jul 7, 6:14 PM EDTSevere Thunderstorm WatchSPC3 hr
Jul 14, 3:39 AM EDTExcessive Heat WatchPHI36 hr
Jul 15, 3:44 PM EDTExcessive Heat WarningPHI4 days
Jul 15, 8:27 PM EDTSpecial Weather StatementPHI63 min
Jul 15, 8:58 PM EDTSpecial Weather StatementPHI62 min
Jul 18, 10:25 AM EDTMesoscale DiscussionSPC2 hr
Jul 18, 12:41 PM EDTSevere Thunderstorm WatchSPC8 hr
Jul 18, 3:44 PM EDTMesoscale DiscussionSPC91 min
Jul 18, 5:51 PM EDTSpecial Weather StatementPHI54 min
Jul 20, 5:03 AM EDTAreal Flood AdvisoryPHI105 min
Jul 20, 5:43 AM EDTSpecial Weather StatementPHI92 min
Jul 20, 5:44 AM EDTAreal Flood AdvisoryPHI63 min
Jul 23, 1:24 PM EDTSevere Thunderstorm WatchSPC10 hr
Jul 23, 5:56 PM EDTSpecial Weather StatementPHI64 min
Jul 25, 3:09 PM EDTExcessive Heat WarningPHI51 hr
Jul 26, 3:37 PM EDTMesoscale DiscussionSPC113 min
Jul 26, 3:57 PM EDTSevere Thunderstorm WatchSPC6 hr
Jul 26, 6:04 PM EDTMesoscale DiscussionSPC86 min
Jul 26, 6:46 PM EDTSevere Thunderstorm WarningPHI89 min
Jul 26, 7:28 PM EDTMesoscale DiscussionSPC92 min
Jul 28, 12:26 PM EDTMesoscale DiscussionSPC2 hr
Jul 28, 1:36 PM EDTSevere Thunderstorm WatchSPC8 hr
Jul 28, 1:46 PM EDTSpecial Weather StatementPHI59 min
Jul 28, 2:18 PM EDTAreal Flood AdvisoryPHI3 hr
Jul 28, 4:18 PM EDTMesoscale DiscussionSPC87 min
Jul 28, 5:06 PM EDTSpecial Weather StatementPHI54 min
Jul 28, 8:26 PM EDTAreal Flood AdvisoryPHI101 min
Jul 28, 9:11 PM EDTSpecial Weather StatementPHI64 min
Jul 31, 9:51 PM EDTCoastal Flood StatementPHI5 hr
Aug 1, 3:31 PM EDTCoastal Flood StatementPHI11 hr
Aug 1, 3:35 PM EDTSpecial Weather StatementPHI55 min
Aug 1, 4:53 PM EDTSpecial Weather StatementPHI67 min
Aug 1, 5:06 PM EDTAreal Flood AdvisoryPHI12 min
Aug 1, 5:09 PM EDTFlash Flood WarningPHI3 hr
Aug 1, 5:46 PM EDTSevere Thunderstorm WarningPHI31 min
Aug 1, 6:16 PM EDTAreal Flood AdvisoryPHI46 min
Aug 2, 2:58 PM EDTHeat AdvisoryPHI28 hr
Aug 3, 5:12 PM EDTSevere Thunderstorm WarningPHI63 min
Aug 3, 6:23 PM EDTSevere Thunderstorm WarningPHI43 min
Aug 4, 1:12 PM EDTSpecial Weather StatementPHI63 min
Aug 4, 1:26 PM EDTSevere Thunderstorm WarningPHI34 min
Aug 5, 2:49 PM EDTMesoscale DiscussionSPC86 min
Aug 5, 3:36 PM EDTSevere Thunderstorm WatchSPC5 hr
Aug 5, 5:22 PM EDTSevere Thunderstorm WarningPHI68 min
Aug 5, 6:16 PM EDTSevere Thunderstorm WarningPHI74 min
Aug 5, 6:38 PM EDTMesoscale DiscussionSPC2 hr
Aug 6, 12:00 AM EDTSpecial Weather StatementPHI60 min
Aug 8, 6:27 AM EDTDense Fog AdvisoryPHI4 hr
Aug 10, 8:21 AM EDTMesoscale DiscussionSPC2 hr
Aug 10, 8:41 AM EDTSpecial Weather StatementPHI94 min
Aug 10, 8:43 AM EDTSpecial Weather StatementPHI92 min
Aug 10, 9:08 AM EDTAreal Flood AdvisoryPHI3 hr
Aug 10, 10:05 AM EDTSpecial Weather StatementPHI115 min
Aug 14, 9:22 AM EDTSevere Thunderstorm WarningPHI38 min
Aug 14, 9:56 AM EDTAreal Flood AdvisoryPHI108 min
Aug 14, 10:07 AM EDTSpecial Weather StatementPHI83 min
Aug 14, 4:15 PM EDTSpecial Weather StatementPHI60 min
Aug 27, 8:25 AM EDTSpecial Weather StatementPHI65 min
Aug 27, 10:00 AM EDTSpecial Weather StatementPHI30 min
Sep 3, 8:05 AM EDTAreal Flood AdvisoryPHI3 hr
Sep 3, 10:28 AM EDTSpecial Weather StatementPHI62 min
Sep 3, 11:14 AM EDTAreal Flood AdvisoryPHI2 hr
Sep 3, 3:00 PM EDTFlash Flood WatchPHI49 hr
Sep 4, 3:41 AM EDTAreal Flood AdvisoryPHI2 hr
Sep 4, 4:00 AM EDTFlash Flood WarningPHI84 min
Sep 4, 12:08 PM EDTAreal Flood WarningPHI4 hr
Sep 4, 12:15 PM EDTAreal Flood WarningPHI106 min
Sep 4, 1:47 PM EDTFlash Flood WarningPHI3 hr
Sep 4, 4:37 PM EDTAreal Flood AdvisoryPHI3 hr
Sep 4, 5:22 PM EDTSpecial Weather StatementPHI53 min
Sep 4, 6:10 PM EDTSevere Thunderstorm WarningPHI65 min
Sep 4, 7:01 PM EDTAreal Flood WarningPHI55 min
Sep 8, 12:15 PM EDTSevere Thunderstorm WatchSPC9 hr
Sep 8, 2:12 PM EDTMesoscale DiscussionSPC93 min
Sep 8, 4:07 PM EDTSpecial Weather StatementPHI83 min
Sep 8, 4:22 PM EDTMesoscale DiscussionSPC53 min
Sep 17, 2:54 PM EDTWind AdvisoryPHI30 hr
Sep 18, 4:13 AM EDTCoastal Flood AdvisoryPHI21 hr
Sep 18, 11:14 AM EDTMesoscale DiscussionSPC91 min
Sep 18, 11:19 AM EDTMesoscale DiscussionSPC86 min
Sep 18, 12:10 PM EDTTornado WatchSPC9 hr
Sep 18, 1:56 PM EDTMesoscale DiscussionSPC64 min
Sep 18, 4:21 PM EDTMesoscale DiscussionSPC114 min
Sep 18, 5:01 PM EDTSevere Thunderstorm WarningPHI59 min
Sep 18, 5:12 PM EDTSevere Thunderstorm WarningPHI78 min
Sep 18, 6:00 PM EDTSevere Thunderstorm WarningPHI60 min
Sep 18, 6:06 PM EDTAreal Flood AdvisoryPHI54 min
Sep 22, 3:09 PM EDTMesoscale DiscussionSPC2 hr
Sep 22, 7:02 PM EDTSpecial Weather StatementPHI58 min
Sep 22, 7:39 PM EDTSevere Thunderstorm WarningPHI66 min
Oct 3, 12:26 AM EDTDense Fog AdvisoryPHI10 hr
Oct 15, 3:25 PM EDTSpecial Weather StatementPHI80 min
Oct 19, 4:15 AM EDTCoastal Flood StatementPHI14 hr
Oct 27, 4:51 AM EDTFlood WatchPHI71 hr
Oct 27, 5:05 AM EDTHigh Wind WatchPHI24 hr
Oct 27, 6:47 AM EDTCoastal Flood WatchPHI23 hr
Oct 27, 5:08 PM EDTCoastal Flood WarningPHI64 hr
Oct 28, 4:35 AM EDTHigh Wind WarningPHI52 hr
Oct 29, 7:40 AM EDTAreal Flood WarningPHI23 hr
Oct 29, 4:28 PM EDTSpecial Weather StatementPHI2 hr
Oct 30, 12:48 AM EDTAreal Flood AdvisoryPHI6 hr
Oct 30, 4:51 AM EDTRiver Flood WarningPHI5 hr
Oct 30, 6:03 AM EDTCoastal Flood AdvisoryPHI20 hr
Oct 30, 8:48 AM EDTWind AdvisoryPHI3 hr
Nov 4, 4:02 AM ESTFreeze WatchPHI11 hr
Nov 4, 2:56 PM ESTFreeze WarningPHI13 hr
Nov 5, 3:20 PM ESTHigh Wind WatchPHI24 hr
Nov 6, 2:52 PM ESTCoastal Flood AdvisoryPHI43 hr
Nov 6, 3:41 PM ESTWind AdvisoryPHI27 hr
Nov 7, 3:40 AM ESTWinter Storm WarningPHI12 hr
Nov 7, 12:55 PM ESTMesoscale DiscussionSPC3 hr
Nov 12, 2:42 AM ESTDense Fog AdvisoryPHI7 hr
Nov 13, 2:36 AM ESTSpecial Weather StatementPHI84 min
Dec 1, 7:09 PM ESTDense Fog AdvisoryPHI14 hr
Dec 9, 7:23 PM ESTDense Fog AdvisoryPHI14 hr
Dec 16, 8:41 PM ESTDense Fog AdvisoryPHI16 hr
Dec 17, 3:27 PM ESTDense Fog AdvisoryPHI12 hr
Dec 18, 1:19 PM ESTSpecial Weather StatementPHI56 min
Dec 18, 2:15 PM ESTSpecial Weather StatementPHI60 min
Dec 20, 3:25 PM ESTCoastal Flood AdvisoryPHI25 hr
Dec 20, 9:11 PM ESTWind AdvisoryPHI12 hr
Dec 21, 12:27 AM ESTCoastal Flood WarningPHI11 hr
Dec 21, 7:49 AM ESTAreal Flood WarningPHI11 hr
Dec 21, 3:16 PM ESTWind AdvisoryPHI27 hr
Dec 25, 3:03 PM ESTFlood WatchPHI36 hr
Dec 26, 2:45 PM ESTCoastal Flood AdvisoryPHI19 hr
Dec 26, 7:55 PM ESTAreal Flood AdvisoryPHI6 hr
Dec 28, 3:49 AM ESTWinter Weather AdvisoryPHI39 hr
Dec 30, 9:53 AM ESTWind AdvisoryPHI6 hr

By product

Every kind of product issued here, grouped by hazard. Each opens the same place narrowed to that product.

The busiest days

Days with the most alerts issued, by UTC date.

Nearby

Alerts in force nowTornadoes on recordForecastThe radar archive20112013

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.