Alert archive / Pennsylvania / Snow Squall Warnings in 2020

Snow Squall Warning 9, NWS Philadelphia/Mount Holly

January 8, 20204 counties in Pennsylvania; Burlington County, Camden County, New Jersey

NWS Philadelphia/Mount Holly issued this snow squall warning at Jan 8, 2020, 12:49 PM EST for 4 counties in Pennsylvania; Burlington County, Camden County, New Jersey. It was in force for 26 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Jan 8, 2020, 12:49 PM EST (17:49 UTC)
Expired
Jan 8, 2020, 1:15 PM EST
In force
26 min
Issued by
NWS Philadelphia/Mount Holly
Area
Storm-based polygon

Counties Burlington County, NJ, Camden County, NJ, Chester County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 57 km from the middle of the area, began a volume at 17:47 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.

The nearest sounding before it

Brookhaven, NY (KOKX), launched 12:00Z, 5.8 hours before the alert went out and 208 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, Brookhaven, NY at 12:00Z on 2020-01-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Brookhaven, NY at 12:00Z on 2020-01-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 35 square meters per square second.1939587897Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
864 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
35 m²/s²
0-3 km storm-relative helicity
123 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

611 
WWUS51 KPHI 081749
SQWPHI

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Snow Squall Warning
National Weather Service Mount Holly NJ
1249 PM EST Wed Jan 8 2020

NJC005-007-PAC029-045-091-101-081815-
/O.NEW.KPHI.SQ.W.0009.200108T1749Z-200108T1815Z/
Camden NJ-Burlington NJ-Montgomery PA-Chester PA-Philadelphia PA-
Delaware PA-
1249 PM EST Wed Jan 8 2020

The National Weather Service in Mount Holly NJ has issued a

* Snow Squall Warning for...
  Northwestern Camden County in southern New Jersey...
  Northwestern Burlington County in southern New Jersey...
  Southeastern Montgomery County in southeastern Pennsylvania...
  Northeastern Chester County in southeastern Pennsylvania...
  Philadelphia County in southeastern Pennsylvania...
  Northeastern Delaware County in southeastern Pennsylvania...

* Until 115 PM EST.

* At 1249 PM EST, a dangerous snow squall was located over Narberth,
  or 7 miles west of Philadelphia, moving east at 40 mph.

  HAZARD...Extremely poor visibility in heavy snow.

  SOURCE...Radar indicated.

  IMPACT...Dangerous life-threatening travel.

* This includes the following highways...
   Interstate 295 in New Jersey near mile marker 28.
   Interstate 95 in Pennsylvania between mile markers 17 and 33.
   Interstate 476 in Pennsylvania between mile markers 7 and 19.
   Pennsylvania Turnpike between exits 326 and 339.
   Northeast Extension near exit A20.
   Interstate 676 in New Jersey between mile markers 0 and 4.
   Interstate 676 in Pennsylvania between mile markers 0 and 1.
   Interstate 76 in New Jersey between mile markers 1 and 3.
   Interstate 76 in Pennsylvania between mile markers 327 and 351.

Locations impacted include...
Philadelphia, Camden, Gloucester City, Norristown, West Norriton,
East Norriton, Bellmawr, Yeadon, Riverside, Conshohocken, Palmyra,
Ambler, Jenkintown, Narberth, East Lansdowne, Beverly, Rockledge,
Brooklawn, Abington and Audubon Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Consider avoiding or delaying travel until the snow squall passes
your location. If you must travel, use extra caution and allow extra
time. Rapid changes in visibility and slick road conditions may lead
to accidents.

&&

LAT...LON 3987 7508 4002 7553 4019 7540 4009 7496
      4006 7498 4005 7497 4007 7494 4008 7490
      4007 7487
TIME...MOT...LOC 1749Z 291DEG 37KT 4004 7527 

$$

JEO
2 follow-up statements
507 
WWUS51 KPHI 081759
SQWPHI

Snow Squall Warning
National Weather Service Mount Holly NJ
1259 PM EST Wed Jan 8 2020

PAC029-081809-
/O.CAN.KPHI.SQ.W.0009.000000T0000Z-200108T1815Z/
Chester PA-
1259 PM EST Wed Jan 8 2020

...THE SNOW SQUALL WARNING FOR NORTHEASTERN CHESTER COUNTY IS
CANCELLED...

The snow squall which prompted the warning has moved out of the 
warned area. Therefore, the snow squall warning has been cancelled.

LAT...LON 3987 7508 3999 7543 4006 7539 4007 7536
      4007 7538 4015 7533 4009 7496 4006 7498
      4005 7497 4007 7493 4007 7487
TIME...MOT...LOC 1759Z 291DEG 37KT 4000 7514 

$$

NJC005-007-PAC045-091-101-081815-
/O.CON.KPHI.SQ.W.0009.000000T0000Z-200108T1815Z/
Camden NJ-Burlington NJ-Montgomery PA-Philadelphia PA-Delaware PA-
1259 PM EST Wed Jan 8 2020

...A SNOW SQUALL WARNING REMAINS IN EFFECT UNTIL 115 PM EST FOR
NORTHWESTERN CAMDEN...NORTHWESTERN BURLINGTON...SOUTHEASTERN
MONTGOMERY...PHILADELPHIA AND NORTHEASTERN DELAWARE COUNTIES...

At 1259 PM EST, a dangerous snow squall was located over
Philadelphia, moving east at 45 mph.

HAZARD...Extremely poor visibility in heavy snow.

SOURCE...Radar and webcams.

IMPACT...Dangerous life-threatening travel.

This includes the following highways...
 Interstate 295 in New Jersey near mile marker 28.
 Interstate 95 in Pennsylvania between mile markers 17 and 33.
 Interstate 476 in Pennsylvania between mile markers 8 and 19.
 Pennsylvania Turnpike near exit 333.
 Northeast Extension near exit A20.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 76 in New Jersey between mile markers 1 and 3.
 Interstate 76 in Pennsylvania between mile markers 329 and 351.

Locations impacted include...
Philadelphia, Camden, Gloucester City, Norristown, West Norriton,
East Norriton, Bellmawr, Yeadon, Riverside, Conshohocken, Palmyra,
Jenkintown, Narberth, East Lansdowne, Beverly, Rockledge, Brooklawn,
Audubon Park, Wissinoming and Morris Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Consider avoiding or delaying travel until the snow squall passes
your location. If you must travel, use extra caution and allow extra
time. Rapid changes in visibility and slick road conditions may lead
to accidents.

&&

LAT...LON 3987 7508 3999 7543 4006 7539 4007 7536
      4007 7538 4015 7533 4009 7496 4006 7498
      4005 7497 4007 7493 4007 7487
TIME...MOT...LOC 1759Z 291DEG 37KT 4000 7514 

$$

JEO
391 
WWUS51 KPHI 081810
SQWPHI

Snow Squall Warning
National Weather Service Mount Holly NJ
110 PM EST Wed Jan 8 2020

NJC005-007-PAC045-091-101-081820-
/O.EXP.KPHI.SQ.W.0009.000000T0000Z-200108T1815Z/
Camden NJ-Burlington NJ-Montgomery PA-Philadelphia PA-Delaware PA-
110 PM EST Wed Jan 8 2020

...THE SNOW SQUALL WARNING FOR NORTHWESTERN CAMDEN...NORTHWESTERN
BURLINGTON...SOUTHEASTERN MONTGOMERY...PHILADELPHIA AND NORTHEASTERN
DELAWARE COUNTIES WILL EXPIRE AT 115 PM EST...

The snow squall which prompted the warning has exited the area.
Therefore, the snow squall warning will be allowed to expire.

LAT...LON 3987 7508 3999 7543 4006 7539 4007 7536
      4007 7538 4015 7533 4009 7496 4006 7498
      4005 7497 4007 7493 4007 7487
TIME...MOT...LOC 1810Z 291DEG 37KT 3997 7503 

$$

JEO

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 8, 7:44 AM ESTSnow Squall WarningPHIChester46 min
Jan 8, 7:49 AM ESTSnow Squall WarningPHICarbon, Monroe, Northampton41 min
Jan 8, 8:28 AM ESTSnow Squall WarningPHIBerks, Bucks, Chester, Delaware, Montgomery47 min
Jan 8, 8:28 AM ESTSnow Squall WarningPHIChester, Delaware, Montgomery, Philadelphia47 min
Jan 8, 8:30 AM ESTSnow Squall WarningPHIMonroe45 min
Jan 8, 11:25 AM ESTSnow Squall WarningPHIBerks35 min
Jan 8, 12:07 PM ESTSpecial Weather StatementPHIMontgomery23 min
Jan 8, 12:38 PM ESTSpecial Weather StatementPHIMontgomery, Philadelphia37 min
Jan 8, 1:48 PM ESTSnow Squall WarningPHICarbon, Monroe42 min
Jan 8, 2:05 PM ESTSpecial Weather StatementPHIMontgomery25 min
Jan 8, 2:32 PM ESTSpecial Weather StatementPHICarbon, Northampton28 min
Jan 8, 2:33 PM ESTSpecial Weather StatementPHIPhiladelphia27 min
Jan 8, 2:46 PM ESTSpecial Weather StatementPHIBerks44 min
Jan 8, 3:05 PM ESTSpecial Weather StatementPHINorthampton40 min
Jan 8, 8:48 AM ESTSnow Squall WarningPHIHunterdon, Middlesex, Morris, Somerset, Warren42 min
Jan 8, 9:14 AM ESTSnow Squall WarningPHIAtlantic, Burlington, Camden, Cumberland, Gloucester, Salem46 min
Jan 8, 9:57 AM ESTSpecial Weather StatementPHIAtlantic33 min
Jan 8, 1:08 PM ESTSnow Squall WarningPHIBurlington, Camden37 min
Jan 8, 2:10 PM ESTSpecial Weather StatementPHISussex35 min
Jan 8, 2:18 PM ESTSnow Squall WarningPHIMorris, Sussex42 min
Jan 8, 4:24 PM ESTSpecial Weather StatementPHIWarren36 min
Jan 8, 6:10 PM ESTSmall Craft AdvisoryPHI13 hr

Nearby

Snow Squall Warnings in Pennsylvania, 2020Snow Squall Warnings in New Jersey, 2020Every snow squall warning in 2020

Sources

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