Alert archive / Pennsylvania / Freeze Watches in 2021

Freeze Watch 4, NWS Philadelphia/Mount Holly

November 1, 20218 counties in Pennsylvania; 5 counties in New Jersey

NWS Philadelphia/Mount Holly issued this freeze watch at Nov 1, 2021, 2:25 PM EDT for 8 counties in Pennsylvania; 5 counties in New Jersey. It took effect at Nov 3, 2021, 12:00 AM EDT. It was in force for .

The area

The counties it named.

The facts

Issued
Nov 1, 2021, 2:25 PM EDT (18:25 UTC)
In effect from
Nov 3, 2021, 12:00 AM EDT
Expired
Nov 2, 2021, 3:30 AM EDT
In force
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 18:28 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, 6.4 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 2021-11-01Temperature 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 2021-11-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 21 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
983 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
21 m²/s²
0-3 km storm-relative helicity
205 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

918 
WWUS71 KPHI 011825
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
225 PM EDT Mon Nov 1 2021

NJZ001-007>010-PAZ054-055-060>062-101>106-020900-
/O.NEW.KPHI.FZ.A.0004.211103T0400Z-211103T1300Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Carbon-Monroe-Berks-
Lehigh-Northampton-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
225 PM EDT Mon Nov 1 2021

...FREEZE WATCH IN EFFECT FROM LATE TUESDAY NIGHT THROUGH
WEDNESDAY MORNING...

* WHAT...Sub-freezing temperatures as low as 30 possible.

* WHERE...Portions of northwest New Jersey and eastern 
  Pennsylvania.

* WHEN...From late Tuesday night through Wednesday morning.

* IMPACTS...Frost and freeze conditions will kill crops and 
  other sensitive vegetation.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take protective measures now as freezing temperatures could
damage or kill tender plants and vegetation. Potted plants should
be brought inside.

&&

$$

Gorse
1 follow-up statement
913 
WWUS71 KPHI 020730
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
330 AM EDT Tue Nov 2 2021

NJZ001-007>010-PAZ054-055-060>062-101>106-022300-
/O.UPG.KPHI.FZ.A.0004.211103T0400Z-211103T1300Z/
/O.NEW.KPHI.FZ.W.0005.211103T0400Z-211103T1300Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Carbon-Monroe-Berks-
Lehigh-Northampton-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Jim Thorpe, Stroudsburg, Reading, 
Allentown, Bethlehem, Easton, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
330 AM EDT Tue Nov 2 2021

...FREEZE WARNING IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM EDT
WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as 29 expected.

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

* WHEN...From midnight tonight to 9 AM EDT Wednesday.

* IMPACTS...Freeze conditions will kill crops and other sensitive
  vegetation.

* ADDITIONAL DETAILS...This will likely bring an end to the
  growing season.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

DEZ001-NJZ012-013-015>023-027-PAZ070-071-022300-
/O.NEW.KPHI.FR.Y.0002.211103T0600Z-211103T1300Z/
New Castle-Middlesex-Western Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-Delaware-Philadelphia-
Including the cities of Wilmington, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Wharton State Forest, Media, and Philadelphia
330 AM EDT Tue Nov 2 2021

...FROST ADVISORY IN EFFECT FROM 2 AM TO 9 AM EDT WEDNESDAY...

* WHAT...Temperatures as low as 33 will result in frost 
  formation.

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

* WHEN...From 2 AM to 9 AM EDT Wednesday.

* IMPACTS...Frost could kill sensitive outdoor vegetation if 
  left uncovered.

* ADDITIONAL DETAILS...Temperatures in the urban areas will likely
  be in the upper 30s, while just outside of the Urban Corridor 
  temperatures will be in the 33 to 36 degree range. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 31, 9:06 PM EDTCoastal Flood StatementPHIOcean8 hr

Nearby

Freeze Watches in Pennsylvania, 2021Freeze Watches in New Jersey, 2021Every freeze 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.