Alert archive / Pennsylvania / Winter Weather Advisories in 2021

Winter Weather Advisory 1, NWS Philadelphia/Mount Holly

January 2, 20218 counties in Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this winter weather advisory at Jan 2, 2021, 2:55 PM EST for 8 counties in Pennsylvania; 5 counties in New Jersey. It took effect at Jan 3, 2021, 5:00 AM EST. It was in force for 23 hr.

The area

The counties it named.

The facts

Issued
Jan 2, 2021, 2:55 PM EST (19:55 UTC)
In effect from
Jan 3, 2021, 5:00 AM EST
Expired
Jan 4, 2021, 4:01 AM EST
In force
23 hr
Issued by
NWS Philadelphia/Mount Holly

Counties Hunterdon County, NJ, Morris County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 103 km from the middle of the area, began a volume at 19:59 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, 7.9 hours before the alert went out and 200 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 2021-01-02Temperature 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 2021-01-02The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 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
434 m above ground
0-6 km bulk shear
97 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
187 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

240 
WWUS41 KPHI 021955
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
255 PM EST Sat Jan 2 2021

NJZ001-PAZ054-055-030900-
/O.NEW.KPHI.WW.Y.0001.210103T1400Z-210104T0600Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
255 PM EST Sat Jan 2 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 AM SUNDAY TO 1 AM EST
MONDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of 1 to 3 inches and ice accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...From 9 AM Sunday to 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007>010-PAZ060>062-101-103-105-030900-
/O.NEW.KPHI.WW.Y.0001.210103T1400Z-210104T0600Z/
Warren-Morris-Hunterdon-Somerset-Berks-Lehigh-Northampton-
Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Washington, Morristown, Flemington, 
Somerville, Reading, Allentown, Bethlehem, Easton, Honey Brook, 
Oxford, Collegeville, Pottstown, Chalfont, and Perkasie
255 PM EST Sat Jan 2 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 AM SUNDAY TO 1 AM EST
MONDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of up to one inch and ice accumulations of a light glaze.

* WHERE...Portions of northern and northwest New Jersey and east 
  central and southeast Pennsylvania.

* WHEN...From 9 AM Sunday to 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Precipitation may start as a mixture of
  freezing rain and sleet before transitioning to mostly plain 
  rain into the afternoon. A brief transition to snow is possible 
  Sunday night before the system exits the region.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

Davis
6 follow-up statements
877 
WWUS41 KPHI 030846
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
346 AM EST Sun Jan 3 2021

NJZ001-PAZ054-055-040000-
/O.EXT.KPHI.WW.Y.0001.210103T1200Z-210104T0600Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
346 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT FROM 7 AM THIS MORNING
TO 1 AM EST MONDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of 1 to 3 inches and ice accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...From 7 AM this morning to 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Precipitation will start out briefly as
  snow this morning, before quickly transitioning to a mixture of
  freezing rain, sleet, and snow. A transition then back over to
  snow will occur this afternoon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ008-040000-
/O.EXT.KPHI.WW.Y.0001.210103T1200Z-210104T0600Z/
Morris-
Including the city of Morristown
346 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT FROM 7 AM THIS MORNING
TO 1 AM EST MONDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of up to one inch and ice accumulations of a light glaze.

* WHERE...Portions of northern and northwest New Jersey and east 
  central and southeast Pennsylvania.

* WHEN...From 7 AM this morning to 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Precipitation will start out as a mixture
  of freezing rain and sleet, before transitioning to plain rain
  by this afternoon. A brief transition to snow is possible tonight
  before the system exits the region.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007-009-010-PAZ060>062-101-103-105-040000-
/O.EXT.KPHI.WW.Y.0001.210103T1000Z-210104T0600Z/
Warren-Hunterdon-Somerset-Berks-Lehigh-Northampton-
Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Washington, Flemington, Somerville, 
Reading, Allentown, Bethlehem, Easton, Honey Brook, Oxford, 
Collegeville, Pottstown, Chalfont, and Perkasie
346 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 1 AM EST MONDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of up to one inch and ice accumulations of a light glaze.

* WHERE...Portions of northern and northwest New Jersey and east 
  central and southeast Pennsylvania.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

* ADDITIONAL DETAILS...Precipitation will start out as a mixture
  of freezing rain and sleet, before transitioning to plain rain
  by this afternoon. A brief transition to snow is possible
  tonight before the system exits the region.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

BAH
398 
WWUS41 KPHI 031448
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
948 AM EST Sun Jan 3 2021

NJZ001-PAZ054-055-040400-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
948 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Mixed precipitation. Additional snow accumulations of 1 
  to 3 inches and ice accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions. Add extra travel
  time.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ008-040400-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Morris-
Including the city of Morristown
948 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Mixed precipitation. Additional snow accumulations of up
  to two inches and ice accumulations of a light glaze.

* WHERE...Morris.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions. Allow extra travel
  time.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007-009-010-PAZ060>062-101-103-105-040400-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Warren-Hunterdon-Somerset-Berks-Lehigh-Northampton-
Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Washington, Flemington, Somerville, 
Reading, Allentown, Bethlehem, Easton, Honey Brook, Oxford, 
Collegeville, Pottstown, Chalfont, and Perkasie
948 AM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Mixed precipitation. Additional snow accumulations of up
  to one inch and ice accumulations of up to one tenth of an inch.

* WHERE...Portions of northern and northwest New Jersey and east 
  central and southeast Pennsylvania.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions. Allow extra travel
  time. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

Davis
568 
WWUS41 KPHI 031826
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
126 PM EST Sun Jan 3 2021

NJZ009-010-PAZ060-101-103-105-031930-
/O.CAN.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Hunterdon-Somerset-Berks-Western Chester-Western Montgomery-
Upper Bucks-
Including the cities of Flemington, Somerville, Reading, 
Honey Brook, Oxford, Collegeville, Pottstown, Chalfont, 
and Perkasie
126 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY IS CANCELLED...

Temperatures have warmed above freezing behind this morning's
round of winter weather. The second round of precipitation is
expected to be mostly rain. 

$$

NJZ001-PAZ054-055-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
126 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Mixed precipitation. Additional snow accumulations of 1 
  to 3 inches and ice accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ008-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Morris-
Including the city of Morristown
126 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Wet snow. Additional snow accumulations of up to two
  inches. A light glaze of freezing rain is also possible. 

* WHERE...Morris.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007-PAZ061-062-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Warren-Lehigh-Northampton-
Including the cities of Washington, Allentown, Bethlehem, 
and Easton
126 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Wet snow. Additional snow accumulations of up to two
  inches. A light glaze of freezing rain is also possible. 

* WHERE...In Pennsylvania, Northampton and Lehigh. In New 
  Jersey, Warren.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

Davis
993 
WWUS41 KPHI 040252
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
952 PM EST Sun Jan 3 2021

NJZ001-PAZ054-055-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
952 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of 1 to 2 inches and ice 
  accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ008-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Morris-
Including the city of Morristown
952 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of up to one inch. A light glaze 
  of freezing rain is also possible.

* WHERE...Morris.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007-PAZ061-062-040600-
/O.CON.KPHI.WW.Y.0001.000000T0000Z-210104T0600Z/
Warren-Lehigh-Northampton-
Including the cities of Washington, Allentown, Bethlehem, 
and Easton
952 PM EST Sun Jan 3 2021

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 1 AM EST
MONDAY...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of up to one inch. A light glaze 
  of freezing rain is also possible.

* WHERE...In Pennsylvania, Northampton and Lehigh. In New 
  Jersey, Warren.

* WHEN...Until 1 AM EST Monday.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling.

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$
048 
WWUS41 KPHI 040519
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
1219 AM EST Mon Jan 4 2021

NJZ001-PAZ054-055-041100-
/O.EXT.KPHI.WW.Y.0001.000000T0000Z-210104T1100Z/
Sussex-Carbon-Monroe-
Including the cities of Newton, Jim Thorpe, and Stroudsburg
1219 AM EST Mon Jan 4 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 6 AM EST EARLY
THIS MORNING...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of 1 to 2 inches and ice 
  accumulations of a light glaze.

* WHERE...In New Jersey, Sussex. In Pennsylvania, Carbon and 
  Monroe.

* WHEN...Until 6 AM EST early this morning.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ008-041100-
/O.EXT.KPHI.WW.Y.0001.000000T0000Z-210104T1100Z/
Morris-
Including the city of Morristown
1219 AM EST Mon Jan 4 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 6 AM EST EARLY
THIS MORNING...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of up to one inch. A light glaze 
  of freezing rain is also possible.

* WHERE...Morris.

* WHEN...Until 6 AM EST early this morning.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$

NJZ007-PAZ061-062-041100-
/O.EXT.KPHI.WW.Y.0001.000000T0000Z-210104T1100Z/
Warren-Lehigh-Northampton-
Including the cities of Washington, Allentown, Bethlehem, 
and Easton
1219 AM EST Mon Jan 4 2021

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 6 AM EST EARLY
THIS MORNING...

* WHAT...Wet snow and freezing rain or freezing drizzle. 
  Additional snow accumulations of up to one inch. A light glaze 
  of freezing rain is also possible.

* WHERE...In Pennsylvania, Northampton and Lehigh. In New 
  Jersey, Warren.

* WHEN...Until 6 AM EST early this morning.

* IMPACTS...Plan on slippery road conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Slow down and use caution while traveling. 

The latest road conditions for the state you are calling from can
be obtained by calling 5 1 1.

&&

$$
884 
WWUS41 KPHI 040901
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
401 AM EST Mon Jan 4 2021

NJZ001-007-008-PAZ054-055-061-062-041015-
/O.CAN.KPHI.WW.Y.0001.000000T0000Z-210104T1100Z/
Sussex-Warren-Morris-Carbon-Monroe-Lehigh-Northampton-
Including the cities of Newton, Washington, Morristown, 
Jim Thorpe, Stroudsburg, Allentown, Bethlehem, and Easton
401 AM EST Mon Jan 4 2021

...WINTER WEATHER ADVISORY IS CANCELLED...

Winter precipitation is coming to an end across the area this
morning. Some drizzle and freezing drizzle may still persist 
slightly longer this morning, however this will be limited. 
Therefore, the advisory has been cancelled.

$$

Nearby

Winter Weather Advisories in Pennsylvania, 2021Winter Weather Advisories in New Jersey, 2021Every winter weather advisory 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.