Heat in Pennsylvania, July 24 to 25, 2001

Name: Heat in Pennsylvania, July 24 to 25, 2001
Start: 2001-07-24T10:00
End: 2001-07-25T19:00
Location: Pennsylvania

July 24 to 25, 2001 · NWS PHI · 5 events in 5 counties and zones

A hot and humid air mass pushed daytime high temperatures into the lower and mid 90s across southeast Pennsylvania on the 24th and 25th. A cold front stalled across the region on the 26th.

Where it happened

Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 2
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 5

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.

What happened

The episode as NWS PHI wrote it up.

A hot and humid air mass pushed daytime high temperatures into the lower and mid 90s across southeast Pennsylvania on the 24th and 25th. A cold front stalled across the region on the 26th. The clouds prevented temperatures from reaching the 90s again. This front slipped south of the region by the morning of the 27th. The heat claimed the life of two men within Philadelphia, a 51-year-old and an 89-year-old. Highest temperatures included 97degrees in Green Lane (Montgomery County), 96 at the Northeast Philadelphia Airport, West Chester (Chester County) and the Willow Grove NAS (Montgomery County), 95 degrees in Neshaminy Falls (Bucks County) and the Franklin Institute within Philadelphia, 94 degrees at the Philadelphia International Airport and New Hope (Bucks County), 93 degrees in Pottstown (Montgomery County) and 92 degrees in Doylestown.

What forecasters said that day

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 Jul 24, 9:07 AM EST, 53 minutes earlier.

Area forecast discussion, Jul 24, 9:07 AM EST, 53 minutes before

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE MOUNT HOLLY NJ
1007 AM EDT TUE JUL 24 2001

SEE WEAK SHORT WAVE ON H5 ANALYSIS AND WATER VAPOR IMAGERY MOVING
INTO ERN GREAT LAKES REGION. MESO ETA HAS THIS AND PUSHES IT BY JUST
TO THE N THIS AFTERNOON. ATMOSPHERE IS FAIRLY MOIST...LWX SOUNDING
HAS 1.57 IN PWATER AND OKX 1.45...AND SHOULD GET MODERATELY
UNSTABLE...LWX AND OKX HAVE FCST CAPES NEAR 2000 J/KG. H8 DWPTS IN
THE 10 TO 15 DEG C RANGE AROUND FA. BELIEVE AS PREV FCSTR THAT SCT
TSTMS COULD PROPOGATE DOWN INTO OUR ENVIRONMENT AFTER BEING
TRIGGERED BY SHORT WAVE. ONLY CHANGE TO PREV FCST IS TO BRING THE
CHC OF THEM A LTL FURTHER S.

LOCAL SCHEMES SUPPORT TEMP FCST AND URBAN HEAT WARNING. WINDS JUST
ABV THE SFC FCST TO INCREASE DURING THE AFTN...AND THAT COULD CAUSE
A WEAKING OF SEA BREEZE AND A MID AFTN RISE IN COASTAL TEMPS...SO
MAY INCREASE AFTN COASTAL TEMPS A LTL. OTHERWISE NO CHANGES TO
TEMPS. PREV AFD BELOW.

MPD

*********************************************************************

LOCAL INTERNET DOWN...SO UNABLE TO VIEW BUFKIT.

PUTTING UP URBAN HEAT WRNG FOR PHILLY METRO AREA. XPC HEAT INDEX
ABOUT 100 BOTH DAYS.

NOT MANY CHGS IN FCST THRU 48 HRS. ADDING CHC TSTMS LATE TDA INTO
THIS EVE IN NWRN ZONES AS INITIAL TROF PUSHES IN LTR TDA...AND JUST
KEEPING MINIMAL CHC LATE DAY TSTMS SUSSEX CTY DE WITH MSTR FM S.

BIG CHGS ARE IN THE EXTDD PD...AS ETA AND AVN BOTH SUG FNT WL HANG UP
JUST TO OUR S THRU AT LEAST THU. SO FOR NOW ADDING CHC POPS FOR SHWRS
TO ALL BUT EXTRM N THU...THOUGH WITH LOW LVL ELY FLOW TO N OF BDRY...
COULD END UP AS JUST OVRNG RAIN HERE.

NOTHING ON THE MARINE. XPC SWLYS TO STAY BLO CRITERIA IN SHORT
TERM...BUT COULD SEE SML CRAFT SEAS AND PERHAPS WNDS IN OTLK PD WITH
NELYS.

.PHI...URBAN HEAT WRNG TDA THRU WED PA67-71 NJ15/17-19 D1.

KRAUS

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

5 heat. Local standard time, as filed.

Heat, Philadelphia

When: July 24, 10:00 AM EST to July 25, 7:00 PM EST
Where: Philadelphia forecast zone
Deaths: 2 direct, 0 indirect
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 40.008, -75.134 (the zone’s center; the record gives no point)

Heat, Bucks

When: July 24, 10:00 AM EST to July 25, 7:00 PM EST
Where: Bucks forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Heat, Chester

When: July 24, 10:00 AM EST to July 25, 7:00 PM EST
Where: Chester forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Heat, Delaware

When: July 24, 10:00 AM EST to July 25, 7:00 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)

Heat, Montgomery

When: July 24, 10:00 AM EST to July 25, 7:00 PM EST
Where: Montgomery forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

The people who died

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, Philadelphia	2001-07-25	89	Male	Permanent Home	Direct
Heat, Philadelphia	2001-07-24	51	Male	Permanent Home	Direct

What these are

Heat: Heat below excessive heat criteria that still caused deaths, injuries or significant impacts.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Pennsylvania in 2001 Every state in 2001 This day in weather history Warnings in Pennsylvania, July 2001

Sources

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: 5260683, 5260684, 5260685, 5260686, 5260687.