Alert archive / New Jersey / Winter Storm Watches in 2021

Winter Storm Watch 4, NWS Philadelphia/Mount Holly

February 16, 20214 states

NWS Philadelphia/Mount Holly issued this winter storm watch at Feb 16, 2021, 3:14 PM EST for 4 states. It took effect at Feb 18, 2021, 4:00 AM EST. It was in force for .

The area

The counties it named.

The facts

Issued
Feb 16, 2021, 3:14 PM EST (20:14 UTC)
In effect from
Feb 18, 2021, 4:00 AM EST
Expired
Feb 17, 2021, 3:43 PM EST
In force
Issued by
NWS Philadelphia/Mount Holly
All 24 counties

New Castle County, DE, Kent County, MD, Burlington County, NJ, Camden County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 73 km from the middle of the area, began a volume at 20:14 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, 8.2 hours before the alert went out and 203 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 2021-02-16Temperature 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 2021-02-16The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 747 square meters per square second.1939587897117Sfc1 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
419 m above ground
0-6 km bulk shear
65 kt
0-1 km storm-relative helicity
747 m²/s²
0-3 km storm-relative helicity
855 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

922 
WWUS41 KPHI 162014
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
314 PM EST Tue Feb 16 2021

NJZ001-007>010-PAZ054-055-060>062-101-103-105-170930-
/O.NEW.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Carbon-Monroe-Berks-
Lehigh-Northampton-Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Honey Brook, Oxford, Collegeville, 
Pottstown, Chalfont, and Perkasie
314 PM EST Tue Feb 16 2021

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
FRIDAY AFTERNOON...

* WHAT...Heavy mixed precipitation possible. Total snow and sleet
  accumulations of 5 to 8 inches.

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

* WHEN...From late Wednesday night through Friday afternoon.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

* ADDITIONAL DETAILS...Precipitation will begin as snow Thursday
  morning, with the heaviest snowfall expected Thursday morning
  into early Thursday afternoon. Sleet and/or freezing rain may
  then mix in Thursday evening into Thursday night. Light wintry
  precipitation will likely continue into the daytime hours on 
  Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation. 

&&

$$

DEZ001-MDZ012-NJZ012-013-015>019-PAZ070-071-102-104-106-170930-
/O.NEW.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
New Castle-Kent MD-Middlesex-Western Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Delaware-Philadelphia-
Eastern Chester-Eastern Montgomery-Lower Bucks-
Including the cities of Wilmington, Chestertown, New Brunswick, 
Freehold, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Media, Philadelphia, West Chester, 
Kennett Square, Norristown, Lansdale, Morrisville, and Doylestown
314 PM EST Tue Feb 16 2021

...WINTER STORM WATCH IN EFFECT FROM LATE WEDNESDAY NIGHT THROUGH
FRIDAY AFTERNOON...

* WHAT...Heavy mixed precipitation possible. Total snow and sleet
  accumulations of 3 to 6 inches and ice accumulations of one 
  tenth to one quarter of an inch possible.

* WHERE...Portions of central, northern and southern New Jersey, 
  southeast Pennsylvania, northeast Maryland and northern 
  Delaware.

* WHEN...From late Wednesday night through Friday afternoon.

* IMPACTS...Travel could be very difficult. The hazardous
  conditions could impact the morning or evening commute.

* ADDITIONAL DETAILS...Precipitation will begin as snow Thursday
  morning, with the heaviest snowfall expected Thursday morning
  into early Thursday afternoon. Sleet and/or freezing rain will
  then mix in Thursday evening into Thursday night. Light wintry 
  precipitation may continue into the daytime hours on Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation. 

&&

$$
2 follow-up statements
384 
WWUS41 KPHI 170841
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
341 AM EST Wed Feb 17 2021

NJZ001-007>010-PAZ054-055-060>062-101-103-105-172200-
/O.CON.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Carbon-Monroe-Berks-
Lehigh-Northampton-Western Chester-Western Montgomery-Upper Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Honey Brook, Oxford, Collegeville, 
Pottstown, Chalfont, and Perkasie
341 AM EST Wed Feb 17 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM LATE TONIGHT THROUGH
FRIDAY AFTERNOON...

* WHAT...Heavy snow possible. Total snow accumulations of 5 to 8 
  inches possible.

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

* WHEN...From late tonight through Friday afternoon.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

* ADDITIONAL DETAILS...Snow overspreads the area early Thursday
  morning and continues through the day and also Thursday night at
  varying intensity. The heaviest snow is expected Thursday 
  morning through early Thursday afternoon. Some sleet may mix in 
  Thursday evening, mainly closer to the I-95 corridor. Light 
  wintry precipitation will likely continue into the daytime hours
  on Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation. 

&&

$$

DEZ001-MDZ012-NJZ012-013-015>019-PAZ070-071-102-104-106-172200-
/O.CON.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
New Castle-Kent MD-Middlesex-Western Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Delaware-Philadelphia-
Eastern Chester-Eastern Montgomery-Lower Bucks-
Including the cities of Wilmington, Chestertown, New Brunswick, 
Freehold, Trenton, Pennsville, Glassboro, Camden, Cherry Hill, 
Moorestown, Mount Holly, Media, Philadelphia, West Chester, 
Kennett Square, Norristown, Lansdale, Morrisville, and Doylestown
341 AM EST Wed Feb 17 2021

...WINTER STORM WATCH REMAINS IN EFFECT FROM LATE TONIGHT THROUGH
FRIDAY AFTERNOON...

* WHAT...Heavy mixed precipitation possible. Total snow and sleet
  accumulations of 4 to 6 inches and ice accumulations of up to
  one tenth of an inch possible.

* WHERE...Portions of central, northern and southern New Jersey, 
  southeast Pennsylvania, northeast Maryland and northern 
  Delaware.

* WHEN...From late tonight through Friday afternoon.

* IMPACTS...Travel could be very difficult. The hazardous 
  conditions could impact the morning or evening commute.

* ADDITIONAL DETAILS...Snow overspreads much of the area early
  Thursday morning, then continues through the day Thursday. The
  heaviest snow is expected Thursday morning through early
  Thursday afternoon. Sleet and/or freezing rain will mix in
  toward later Thursday afternoon and Thursday night especially 
  near and south and east of I-95. Light wintry precipitation 
  should continue into the daytime hours on Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Monitor the latest forecasts for updates on this situation. 

&&

$$

Gorse
999 
WWUS41 KPHI 172043
WSWPHI

URGENT - WINTER WEATHER MESSAGE
National Weather Service Mount Holly NJ
343 PM EST Wed Feb 17 2021

NJZ001-007-008-PAZ054-055-060>062-180945-
/O.UPG.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
/O.NEW.KPHI.WS.W.0003.210218T0900Z-210219T1500Z/
Sussex-Warren-Morris-Carbon-Monroe-Berks-Lehigh-Northampton-
Including the cities of Newton, Washington, Morristown, 
Jim Thorpe, Stroudsburg, Reading, Allentown, Bethlehem, 
and Easton
343 PM EST Wed Feb 17 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM THURSDAY TO 10 AM EST
FRIDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 5 to 8 
  inches.

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

* WHEN...From 4 AM Thursday to 10 AM EST Friday.

* IMPACTS...Travel could be very difficult. The hazardous
  conditions could impact the Thursday morning, Thursday evening,
  and Friday morning commutes.

* ADDITIONAL DETAILS...Snow overspreads the area early Thursday
  morning and continues at varying intensity through the day and
  night, heaviest from late morning through the afternoon. Some
  sleet may mix in Thursday evening and overnight. Light snow will
  likely continue into the daytime hours on Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

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

&&

$$

DEZ001-NJZ009-010-012-013-015>019-PAZ070-071-101>106-180945-
/O.UPG.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
/O.NEW.KPHI.WS.W.0003.210218T0900Z-210219T1500Z/
New Castle-Hunterdon-Somerset-Middlesex-Western Monmouth-Mercer-
Salem-Gloucester-Camden-Northwestern Burlington-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Flemington, Somerville, 
New Brunswick, Freehold, Trenton, Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Media, Philadelphia, 
Honey Brook, Oxford, West Chester, Kennett Square, Collegeville, 
Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville,
and Doylestown
343 PM EST Wed Feb 17 2021

...WINTER STORM WARNING IN EFFECT FROM 4 AM THURSDAY TO 10 AM EST
FRIDAY...

* WHAT...Heavy mixed precipitation expected. Total snow 
  accumulations of 4 to 6 inches and ice accumulations of a 
  light glaze.

* WHERE...Portions of central, northern, northwest and southern 
  New Jersey, southeast Pennsylvania and northern Delaware.

* WHEN...From 4 AM Thursday to 10 AM EST Friday.

* IMPACTS...Travel could be very difficult. The hazardous
  conditions could impact the Thursday morning, Thursday evening,
  and Friday morning commutes.

* ADDITIONAL DETAILS...Snow overspreads the area early Thursday
  morning and could be heavy at times in the morning and early
  afternoon. A change to sleet and freezing rain is expected by
  late afternoon or evening. Light wintry precipitation will 
  likely continue into the daytime hours on Friday.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If you must travel, keep an extra flashlight, food, and water in
your vehicle in case of an emergency. 

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

&&

$$

MDZ012-180945-
/O.UPG.KPHI.WS.A.0004.210218T0900Z-210219T1800Z/
/O.NEW.KPHI.WW.Y.0009.210218T0900Z-210219T1500Z/
Kent MD-
Including the city of Chestertown
343 PM EST Wed Feb 17 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 10 AM
EST FRIDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations 
  of 2 to 4 inches and ice accumulations of up to one tenth of 
  an inch.

* WHERE...Kent MD.

* WHEN...From 4 AM Thursday to 10 AM EST Friday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the Thursday morning, Thursday evening,
  and Friday morning commutes.

* ADDITIONAL DETAILS...Snow overspreads the area early Thursday
  morning and could be heavy at times in the morning. A change to
  sleet and freezing rain is expected by afternoon. Light wintry 
  precipitation will likely continue into the daytime hours on 
  Friday.

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.

&&

$$

DEZ002-MDZ015-019-020-NJZ014-020>022-025>027-180945-
/O.NEW.KPHI.WW.Y.0009.210218T0900Z-210219T1500Z/
Kent-Queen Annes-Talbot-Caroline-Eastern Monmouth-Ocean-
Cumberland-Atlantic-Coastal Atlantic-Coastal Ocean-
Southeastern Burlington-
Including the cities of Dover, Centreville, Easton, Denton, 
Sandy Hook, Jackson, Millville, Hammonton, Atlantic City, 
Long Beach Island, and Wharton State Forest
343 PM EST Wed Feb 17 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 10 AM
EST FRIDAY...

* WHAT...Mixed precipitation expected. Total snow accumulations of
  1 to 3 inches and ice accumulations of up to one tenth of an 
  inch.

* WHERE...Portions of central and southern New Jersey, northeast 
  Maryland and central Delaware.

* WHEN...From 4 AM Thursday to 10 AM EST Friday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the Thursday morning, Thursday evening,
  and Friday morning commutes.

* ADDITIONAL DETAILS...Snow overspreads the area early Thursday
  morning and could be heavy at times in the morning. A change to
  sleet and freezing rain is expected by afternoon. Light wintry 
  precipitation will likely continue into the daytime hours on 
  Friday.

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.

&&

$$

DEZ003-NJZ023-180945-
/O.NEW.KPHI.WW.Y.0009.210218T0900Z-210219T1500Z/
Inland Sussex-Cape May-
Including the cities of Georgetown and Cape May Court House
343 PM EST Wed Feb 17 2021

...WINTER WEATHER ADVISORY IN EFFECT FROM 4 AM THURSDAY TO 10 AM
EST FRIDAY...

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

* WHERE...In New Jersey, Cape May. In Delaware, Inland Sussex.

* WHEN...From 4 AM Thursday to 10 AM EST Friday.

* IMPACTS...Plan on slippery road conditions. The hazardous
  conditions could impact the Thursday morning, Thursday evening,
  and Friday morning commutes.

* ADDITIONAL DETAILS...Snow or mixed precipitation overspreads the
  area early Thursday morning. A change from snow to sleet, or 
  from sleet and freeing rain to plain rain, is expected through 
  the day on Thursday. Light mixed precipitation will likely 
  continue into the daytime hours on Friday.

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.

&&

$$

CMS/PO/JEO

Nearby

Winter Storm Watches in New Jersey, 2021Winter Storm Watches in Pennsylvania, 2021Winter Storm Watches in Delaware, 2021Every winter storm watch 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.