Heat, Delaware
- When
- August 6, 9:00 AM EST to August 10, 6:00 PM EST
- Where
- Delaware forecast zone
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 39.917, -75.399 (the zone’s center; the record gives no point)
A ridge of high pressure both surface and aloft that was broiling the central part of the country moved east and covered Eastern Pennsylvania during the work week of August 6th. This brought a very oppressive hot spell to the region and peaked on the 9th.
Every event with a place to put it; 7 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS PHI wrote it up.
A ridge of high pressure both surface and aloft that was broiling the central part of the country moved east and covered Eastern Pennsylvania during the work week of August 6th. This brought a very oppressive hot spell to the region and peaked on the 9th. It was the first time since July 9th and 10th of 1993 that the high temperature reached 100 degrees or higher at the Philadelphia International Airport. There were 25 heat related deaths in the Greater Philadelphia Metropolitan Area: 19 in Philadelphia, 2 in Montgomery County, 1 in Chester County and 3 elsewhere. In most instances, the circumstances were the same. The people already had underlying health problems. They were found indoors with windows closed and air-conditioning units (if available) not turned on. The living room temperature of one of the deceased in Philadelphia was 130 degrees. Responses for assistance for the elderly in Philadelphia increased from 33 on Monday the 6th to 126 on Thursday the 9th. Dozens of others suffered heat exhaustion. At the Philadelphia Phillies afternoon baseball game on the 9th, the artificial turf temperature rose to 149 degrees by games' end. Twenty-four fans were treated for heat exhaustion. The hot weather and lack of wind produced unhealthy ozone levels. The Delaware Valley Regional Planning Commission issued a "code red" warning for ground level ozone concentration. The hot weather put a strain on both electrical and water usage with several utilities setting records. The PJM Interconnection (An independent organization that coordinates electric delivery for 22 million people in Maryland, Delaware, Pennsylvania and New Jersey) set a usage record of 54,176 megawatts on the 9th. It was also forced to reduce voltage by 5 percent that day between 310 p.m. and 615 p.m. EDT to protect power reserves. PECO Energy had its 2nd highest usage on record on the 9th (7,954 megawatts). Both GPU Energy (10,468 megawatts) and PPL (6,661 megawatts) established new usage records on the 9th. Scattered outages occurred because of the peak demand. On the night of the 9th, 2,500 customers in Upper Darby (Delaware County) were without power for twelve hours. Water usage at the Philadelphia Suburban Water Company shattered records for four consecutive days and was about 17% above the July average. The National Utility called on its Lehigh and Monroe County customers to conserve water.On the 8th and 9th, school children were dismissed early from Philadelphia Public Schools. University of Pennsylvania also dismissed non-essential personnel early. Interstate 95 buckled near Philadelphia International Airport. In and around Philadelphia, SEPTA Regional Rail Lines operated with delays due to downed wires on the 9th. The wires sagged because of the heat and a couple of trains ripped them from their moorings. Several trains and buses overheated. Chester County recommended restrain from outside burning until temperatures cooled.Highest temperatures included 104 degrees in Willow Grove (Montgomery County), 103 degrees in Northeast Philadelphia, 101 degrees in Pottstown (Montgomery County) and at the Philadelphia International Airport, 99 degrees in Doylestown (Bucks County), 98 degrees at the Lehigh Valley International Airport and East Stroudsburg (Monroe County) and 91 degrees in Mount Pocono (Monroe County). The 101 degree high temperature at the Philadelphia International Airport was the hottest day at the airport since July 15, 1995 when it reached 103 degrees. A cold front moved into the region the evening of the 10th and stalled throughout the weekend (the 11th and 12th). While it did not remove the humid air in place, the clouds and precipitation prevented temperatures from reaching into the 90s after the 10th.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Aug 6, 12:42 AM EST, 8 hours 18 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 142 AM EDT MON AUG 6 2001 THE HUMID AIRMASS IS ALREADY IN PLACE AND THE HOT AIRMASS ARRIVES TONIGHT...BUT BECOMES HOTTER TUESDAY. I WILL ISSUE AN EXCESSIVE HEAT WARNING FOR MOST OF CENTRAL AND SOUTH NEW JERSEY...SE PA...DEL AND NE MD...BUT WILL LEAVE COASTAL ZONES OUT AS A SEABREEZE SHOULD FORM TODAY. SOME OF THE HOT AIR FROM THE UPPER MIDWEST SPILLS OVER THE RIDGE AND ACROSS THE FORECAST AREA THROUGH TUE. BY TUE AFTN THE FCST 850 TEMPS APPROACH 20 WHILE TODAY THEY ARE NOT QUITE AS HIGH. MODELS SUGGEST PSBL TSTM DVLPMNT THIS EVENING. MESOETA PUTS A BULLSEYE VV MAX OVER PHL. THE NGM/AVN ARE MORE CONSERVATIVE. SINCE IT WOULD BE A MESOSCALE INFLUENCE THAT WOULD CAUSE ANY TSTM DVLPMNT...I AM NOT CONFIDENT ENOUGH TO INCLUDE SINCE ACTUAL COVERAGE SHOULD BE SMALL IF TSTMS DO FORM. ALTHOUGH THERE IS GOOD INSTABILITY IN PLACE...MOISTURE IS MARGINAL. FWC TEMPS GENLY OK TODAY...BUT TMRW THEY LOOK A BIT HIGH. HOWEVER...FWC DEWPTS LOOK A BIT LOW THROUGH THE PERIOD AND HAVE BEEN RUNNING A CPL DEGREES LOW. THE SWITCH TO NW FLOW FOR TUE SHOULD ALLOW A SMALL DROP IN DEWPTS WITH SOME MIXING OF DRY AIR DOWN FROM ALFT...BUT THE TEMPS SHOULD BE HIGHER THAT TODAY. BASED ON FCST TEMPS/DEWPTS...THE HEAT INDEX WHERE I WILL ISSUE AN EXCESSIVE HEAT WARNING SHOULD REACH 100 TO 105 TODAY AND AROUND 105 (UP TO 107) TUE. I WILL ALSO HEADLINE THE HEAT INDEX OF NEAR 100 FOR LEHIGH VALLEY AND NRN NJ. MPO 89 70 90 69 / 10 10 10 0 ABE 92 71 94 70 / 10 10 10 0 RDG 93 72 94 70 / 10 10 10 0 PHL 94 75 97 76 / 10 20 10 0 12N 91 70 92 70 / 10 10 10 0 SMQ 93 74 96 74 / 10 10 10 0 TTN 93 74 96 74 / 10 10 10 0 MIV 93 74 97 74 / 10 20 10 0 ACY 88 74 95 74 / 10 20 10 0 ILG 94 74 97 74 / 10 20 10 0 DOV 93 74 97 74 / 10 20 10 0 GED 93 74 96 74 / 10 20 10 0 ESN 93 74 96 74 / 10 20 10 0 .PHI... DE...EXCESSIVE HEAT WARNING ALL BUT THE COAST. MD...EXCESSIVE HEAT WARNING. NJ...EXCESSIVE HEAT WARNING NJ9/10/12/13/15>23. PA...EXCESSIVE HEAT WARNING PA67>71.
The national radar mosaic for the moment the first event began.
10 heat. Local standard time, as filed.
As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.
| Event | Date | Age | Sex | Where | Kind |
|---|---|---|---|---|---|
| Heat, Montgomery | 2001-08-08 | 56 | Male | Permanent Home | Direct |
| Heat, Montgomery | 2001-08-10 | 79 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-07 | 78 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-08 | 71 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-08 | 66 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-08 | 79 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-09 | 81 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 49 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 50 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 88 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 81 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 71 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-10 | 82 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-11 | 63 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-11 | 50 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-11 | 61 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-11 | 88 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-12 | 81 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-13 | 51 | Male | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-15 | 62 | Female | Permanent Home | Direct |
| Heat, Philadelphia | 2001-08-16 | 75 | Male | Permanent Home | Direct |
| Heat, Chester | 2001-08-08 | 76 | Male | Permanent Home | Direct |
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Pennsylvania in 2001Every state in 2001This day in weather historyWarnings in Pennsylvania, August 2001
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 5265972, 5265973, 5265974, 5266702, 5266703, 5265975, 5265976, 5265977, 5265978, 5265979.