Alert archive / New Jersey / Special Weather Statements in 2021

Special Weather Statement, NWS Philadelphia/Mount Holly

January 20, 20216 counties in New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this special weather statement at Jan 20, 2021, 10:42 AM EST for 6 counties in New Jersey; 4 counties in Pennsylvania. It was in force for 63 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 20, 2021, 10:42 AM EST (15:42 UTC)
Expired
Jan 20, 2021, 11:45 AM EST
In force
63 min
Issued by
NWS Philadelphia/Mount Holly

Counties Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Somerset County, NJ, Bucks County, PA, Delaware County, PA, Montgomery County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 64 km from the middle of the area, began a volume at 15:42 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, 3.7 hours before the alert went out and 139 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 2021-01-20Temperature 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 2021-01-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -7 square meters per square second.1939587897117136Sfc1 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
1247 m above ground
0-6 km bulk shear
74 kt
0-1 km storm-relative helicity
-7 m²/s²
0-3 km storm-relative helicity
195 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

294 
WWUS81 KPHI 201542
SPSPHI

Special Weather Statement
National Weather Service Mount Holly NJ
1042 AM EST Wed Jan 20 2021

DEZ001-NJZ008>010-012>020-PAZ060-070-071-101>106-201645-
New Castle-Salem-Camden-Mercer-Morris-Hunterdon-Northwestern
Burlington-Eastern Monmouth-Ocean-Western
Monmouth-Somerset-Middlesex-Gloucester-Lower Bucks-Eastern
Montgomery-Western Chester-Philadelphia-Upper Bucks-Western
Montgomery-Delaware-Eastern Chester-Berks-
1042 AM EST Wed Jan 20 2021

...A SNOW SQUALL WILL AFFECT NORTHEASTERN NEW CASTLE...NORTHWESTERN
OCEAN...NORTHWESTERN CAMDEN...MERCER...SOMERSET...NORTHWESTERN
SALEM...MORRIS...HUNTERDON...NORTHWESTERN GLOUCESTER...NORTHWESTERN
BURLINGTON...MONMOUTH...MIDDLESEX...MONTGOMERY...SOUTHEASTERN
BERKS...BUCKS...NORTHEASTERN CHESTER...PHILADELPHIA AND DELAWARE
COUNTIES...

At 1039 AM EST, a snow squall was located along a line extending from
near Kinnelon to near Clinton to near Perkasie to near Adamstown.
Movement was southeast at 35 mph. This squall has the potential to 
briefly drop visibilities below one half mile and result in a light 
coating of snow on roadways.

Locations impacted include...
Philadelphia, Trenton, Camden, New Brunswick, Perth Amboy, West
Chester, Morristown, Somerville, Gloucester City, Sandy Hook,
Somerset, Edison, Cherry Hill, Middletown, Old Bridge, Bensalem, East
Brunswick, Bridgewater, South Brunswick and Sayreville.

This includes the following highways...
 New Jersey Turnpike between exits 3 and 13.
 Pennsylvania Turnpike between mile markers 295 and 359.
 Northeast Extension between mile markers 21 and 41.
 Interstate 95 in Pennsylvania between mile markers 0 and 40.
 Interstate 95 in Delaware between mile markers 19 and 23.
 Interstate 76 in Pennsylvania between mile markers 327 and 351.
 Interstate 76 in New Jersey between mile markers 0 and 3.
 Interstate 78 in New Jersey between mile markers 17 and 42.
 Interstate 80 in New Jersey between mile markers 32 and 46.
 Interstate 195 in New Jersey between mile markers 0 and 23.
 Interstate 295 in New Jersey between mile markers 9 and 30, and
between mile markers 33 and 76.
 Interstate 287 in New Jersey between mile markers 0 and 54.
 Interstate 676 in Pennsylvania between mile markers 0 and 1.
 Interstate 676 in New Jersey between mile markers 0 and 4.
 Interstate 476 in Pennsylvania between mile markers 0 and 19.
 Interstate 176 in Pennsylvania between mile markers 1 and 9.
 Garden State Parkway between mile markers 107 and 134.

Use extra caution if you must travel into or through this dangerous
snow squall. Rapid changes in visibility and potentially slick roads
are likely to lead to accidents. Consider delaying travel until the
squall passes your location.

Conditions can deteriorate rapidly in winter weather situations. Be
prepared for snow or ice covered roads. Slow down and allow extra
time when traveling.

LAT...LON 4025 7412 4007 7447 3973 7543 4025 7604
      4043 7530 4060 7495 4106 7445 4102 7443
      4100 7430 4090 7427 4091 7434 4060 7446
      4060 7421 4050 7428 4046 7425 4041 7403
      4044 7399 4048 7402 4048 7401 4043 7397
TIME...MOT...LOC 1539Z 298DEG 32KT 4103 7440 4058 7490 4041 7525 4024
7599

$$

NC

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 20, 9:52 AM ESTSpecial Weather StatementPHIHunterdon, Somerset, Warren53 min
Jan 20, 12:02 PM ESTSpecial Marine WarningPHI58 min
Jan 20, 1:00 PM ESTSpecial Marine WarningPHI65 min
Jan 20, 8:56 AM ESTSpecial Weather StatementPHICarbon, Monroe49 min

Nearby

Special Weather Statements in New Jersey, 2021Special 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.