Alert archive / Pennsylvania / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

July 1, 2021Chester County, Montgomery County, Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Jul 1, 2021, 2:51 PM EDT for Chester County, Montgomery County, Pennsylvania. It was in force for 39 min. 7 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 1, 2021, 2:51 PM EDT (18:51 UTC)
Expired
Jul 1, 2021, 3:30 PM EDT
In force
39 min
Issued by
NWS Philadelphia/Mount Holly

Counties Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 115 km from the middle of the area, began a volume at 18:51 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Jul 1, 3:13 PM EDTTSTM WND DMG4 Nne West Sadsbury Twp, PADOWNED TREE ON LAMMEY ROAD. TIME ESTIMATED FROM RADAR.
Jul 1, 3:21 PM EDTTSTM WND DMG2 Nnw Geryville, PADOWNED WIRES NEAR ELM ROAD. TIME ESTIMATED FROM RADAR.
Jul 1, 3:21 PM EDTTSTM WND DMG2 Wnw Caln Twp, PADOWNED TREE ON FISHERVILLE ROAD. TIME ESTIMATED FROM RADAR.
Jul 1, 3:23 PM EDTTSTM WND DMG2 Sw Gilbertsville, PAMPING REPORT OF DOWNED TREE LIMBS AND POWER LINES NEAR ROUTE 100. TIME ESTIMATED FROM RADAR.
Jul 1, 3:26 PM EDTTSTM WND DMG1 N Coatesville, PADOWNED TREES AND WIRES NEAR VALLEY STATION ROAD IN COATESVILLE. TIME ESTIMATED FROM RADAR.
Jul 1, 3:27 PM EDTTSTM WND DMG1 Ne Thorndale, PADOWNED TREE ON BEAVER RUN ROAD. TIME ESTIMATED FROM RADAR.
Jul 1, 3:31 PM EDTTSTM WND DMG1 W Chester Springs, PADOWNED WIRES NEAR HORSESHOE TRAIL. TIME ESTIMATED FROM RADAR.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 6.9 hours before the alert went out and 188 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2021-07-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 604 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2021-07-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 61 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
604 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
928 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
61 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.2

Open this sounding in Storm Lab

The text

As transmitted.

867 
WWUS81 KPHI 011851
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
251 PM EDT Thu Jul 1 2021

DEZ001-PAZ060-061-070-101>103-105-011930-
New Castle-Upper Bucks-Lehigh-Western Montgomery-Delaware-Western
Chester-Eastern Chester-Berks-
251 PM EDT Thu Jul 1 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN NEW CASTLE...
SOUTHEASTERN BERKS...SOUTHEASTERN LEHIGH...NORTHWESTERN MONTGOMERY...
WEST CENTRAL BUCKS...CHESTER AND WEST CENTRAL DELAWARE COUNTIES...

At 251 PM EDT, a strong thunderstorm was located over New Morgan, or
9 miles south of Reading, moving east at 55 mph.

Wind gusts up to 50 mph and pea size hail are possible with this
storm.

Locations impacted include...
Reading, West Chester, Pottstown, Phoenixville, Coatesville, Emmaus,
Westtown, Wyomissing, Downingtown, Kennett Square, Birdsboro,
Collegeville, Oxford, Royersford, Laureldale, Parkesburg, Trappe,
East Greenville, West Grove and Honey Brook.

This includes the following highways...
 Pennsylvania Turnpike between mile markers 296 and 324.
 Northeast Extension between mile markers 37 and 52.
 Interstate 78 in Pennsylvania between mile markers 61 and 62.
 Interstate 176 in Pennsylvania between mile markers 1 and 11.

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3976 7606 3987 7599 3995 7600 4004 7593
      4011 7594 4014 7588 4023 7602 4036 7598
      4057 7541 4021 7537 4018 7541 4016 7540
      4011 7543 4010 7546 4009 7544 3972 7565
      3972 7613
TIME...MOT...LOC 1851Z 249DEG 49KT 4020 7591 

$$

Davis

The office that day

Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 30, 8:37 PM EDTSevere Thunderstorm WarningPHIHunterdon, Mercer38 min
Jun 30, 8:56 PM EDTSpecial Marine WarningPHI94 min
Jun 30, 9:05 PM EDTSpecial Weather StatementPHISomerset40 min
Jun 30, 9:21 PM EDTSpecial Weather StatementPHISalem39 min
Jun 30, 9:49 PM EDTSpecial Weather StatementPHIMonmouth26 min
Jun 30, 9:51 PM EDTSpecial Marine WarningPHI60 min
Jul 1, 2:58 AM EDTSmall Craft AdvisoryPHI17 hr
Jul 1, 1:10 PM EDTSpecial Weather StatementPHIMonmouth50 min
Jul 1, 1:16 PM EDTSpecial Weather StatementPHIAtlantic29 min
Jul 1, 1:28 PM EDTSpecial Marine WarningPHI62 min
Jul 1, 1:31 PM EDTSpecial Weather StatementPHICumberland29 min
Jul 1, 4:21 PM EDTSpecial Marine WarningPHI114 min
Jul 1, 4:27 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Hunterdon, Mercer, Salem and 1 more48 min
Jul 1, 4:55 PM EDTSevere Thunderstorm WarningPHICape May, Cumberland, Salem80 min
Jul 1, 4:59 PM EDTSevere Thunderstorm WarningPHIBurlington, Camden, Gloucester, Mercer, Middlesex, Monmouth and 2 more46 min
Jul 1, 5:02 PM EDTTornado WarningPHIBurlington, Mercer28 min
Jul 1, 5:27 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 5 more93 min
Jul 1, 5:35 PM EDTTornado WarningPHIMercer, Monmouth, Ocean25 min
Jul 1, 5:40 PM EDTSpecial Marine WarningPHI65 min
Jul 1, 5:46 PM EDTSpecial Marine WarningPHI119 min
Jul 1, 6:13 PM EDTSpecial Marine WarningPHI92 min
Jun 30, 8:16 PM EDTSpecial Weather StatementPHIBucks, Montgomery44 min
Jul 1, 3:13 PM EDTSevere Thunderstorm WarningPHIBerks, Bucks, Chester, Lehigh, Montgomery47 min
Jul 1, 3:23 PM EDTAreal Flood AdvisoryPHIChester, Montgomery77 min
Jul 1, 3:48 PM EDTAreal Flood AdvisoryPHIBucks, Delaware, Montgomery, Philadelphia112 min
Jul 1, 3:50 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Philadelphia40 min
Jul 1, 4:08 PM EDTSevere Thunderstorm WarningPHISussex52 min
Jul 1, 4:08 PM EDTSevere Thunderstorm WarningPHIKent52 min
Jul 1, 4:10 PM EDTAreal Flood AdvisoryPHIKent, New Castle94 min
Jul 1, 4:32 PM EDTSevere Thunderstorm WarningPHIKent, New Castle, Sussex43 min
Jul 1, 4:57 PM EDTTornado WarningPHIKent, Sussex22 min
Jul 1, 5:12 PM EDTSevere Thunderstorm WarningPHIKent, Sussex48 min
Jul 1, 3:12 PM EDTSevere Thunderstorm WarningPHIKent, Queen Anne's, Talbot48 min
Jul 1, 3:56 PM EDTSevere Thunderstorm WarningPHICaroline, Kent, Queen Anne's, Talbot49 min

Nearby

Special Weather Statements in Pennsylvania, 2021Every special weather statement in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.