Alert archive / New Jersey / Frost Advisories in 2024

Frost Advisory 3, NWS Philadelphia/Mount Holly

April 21, 202416 counties in New Jersey; 7 counties in Pennsylvania; New Castle County, Delaware

NWS Philadelphia/Mount Holly issued this frost advisory at Apr 21, 2024, 3:16 PM EDT for 16 counties in New Jersey; 7 counties in Pennsylvania; New Castle County, Delaware. It took effect at Apr 22, 2024, 2:00 AM EDT. It was in force for 7 hr.

The area

The counties it named.

The facts

Issued
Apr 21, 2024, 3:16 PM EDT (19:16 UTC)
In effect from
Apr 22, 2024, 2:00 AM EDT
Expired
Apr 22, 2024, 9:00 AM EDT
In force
7 hr
Issued by
NWS Philadelphia/Mount Holly
All 24 counties

New Castle County, DE, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cape May County, NJ, Cumberland County, NJ, Gloucester County, NJ, Hunterdon County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Morris County, NJ, Ocean County, NJ, Salem County, NJ, Somerset County, NJ, Sussex County, NJ, Warren County, NJ, Berks County, PA, Bucks County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Montgomery County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 55 km from the middle of the area, began a volume at 19:18 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, 7.3 hours before the alert went out and 198 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 2024-04-21Temperature 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 2024-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -124 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
1523 m above ground
0-6 km bulk shear
82 kt
0-1 km storm-relative helicity
-124 m²/s²
0-3 km storm-relative helicity
196 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

236 
WWUS71 KPHI 211916
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
316 PM EDT Sun Apr 21 2024

NJZ001-007>009-PAZ060>062-101>103-105-221000-
/O.NEW.KPHI.FR.Y.0003.240422T0600Z-240422T1300Z/
Sussex-Warren-Morris-Hunterdon-Berks-Lehigh-Northampton-
Western Chester-Eastern Chester-Western Montgomery-Upper Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Reading, Allentown, Bethlehem, Easton, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Chalfont, and Perkasie
316 PM EDT Sun Apr 21 2024

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

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

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

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

MPS
3 follow-up statements
784 
WWUS71 KPHI 212257
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
657 PM EDT Sun Apr 21 2024

NJZ010-PAZ070-104-106-221200-
/O.EXA.KPHI.FR.Y.0003.240422T0600Z-240422T1300Z/
Somerset-Delaware-Eastern Montgomery-Lower Bucks-
Including the cities of Somerville, Media, Norristown, Lansdale, 
Morrisville, and Doylestown
657 PM EDT Sun Apr 21 2024

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

* WHAT...Temperatures as low as 35 will result in frost 
  formation.

* WHERE...In New Jersey, Somerset. In Pennsylvania, Delaware, 
  Eastern Montgomery and Lower Bucks.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

DEZ001-NJZ012-013-015>023-027-221200-
/O.EXA.KPHI.FR.Y.0003.240422T0600Z-240422T1300Z/
New Castle-Middlesex-Western Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-
Including the cities of Wilmington, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
and Wharton State Forest
657 PM EDT Sun Apr 21 2024

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

* WHAT...Temperatures as low as 36 will result in frost 
  formation.

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

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

NJZ001-007>009-PAZ060>062-101>103-105-221200-
/O.CON.KPHI.FR.Y.0003.240422T0600Z-240422T1300Z/
Sussex-Warren-Morris-Hunterdon-Berks-Lehigh-Northampton-
Western Chester-Eastern Chester-Western Montgomery-Upper Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Reading, Allentown, Bethlehem, Easton, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Chalfont, and Perkasie
657 PM EDT Sun Apr 21 2024

...FROST ADVISORY REMAINS IN EFFECT FROM 2 AM TO 9 AM EDT
MONDAY...

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

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

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

Wunderlin
033 
WWUS71 KPHI 220723
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
323 AM EDT Mon Apr 22 2024

NJZ001-007>010-PAZ060>062-070-101>106-221300-
/O.CON.KPHI.FR.Y.0003.000000T0000Z-240422T1300Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Berks-Lehigh-Northampton-
Delaware-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Reading, Allentown, Bethlehem, Easton, 
Media, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
323 AM EDT Mon Apr 22 2024

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM EDT THIS MORNING...

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

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

* WHEN...Until 9 AM EDT this morning.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

DEZ001-NJZ012-013-015>023-027-221300-
/O.CON.KPHI.FR.Y.0003.000000T0000Z-240422T1300Z/
New Castle-Middlesex-Western Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-
Including the cities of Wilmington, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
and Wharton State Forest
323 AM EDT Mon Apr 22 2024

...FROST ADVISORY REMAINS IN EFFECT UNTIL 9 AM EDT THIS MORNING...

* WHAT...Temperatures as low as 34 degrees will result in frost 
  formation.

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

* WHEN...Until 9 AM EDT this morning.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
223 
WWUS71 KPHI 221252
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
852 AM EDT Mon Apr 22 2024

NJZ001-007>010-PAZ060>062-070-101>106-221400-
/O.EXP.KPHI.FR.Y.0003.000000T0000Z-240422T1300Z/
Sussex-Warren-Morris-Hunterdon-Somerset-Berks-Lehigh-Northampton-
Delaware-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Newton, Washington, Morristown, 
Flemington, Somerville, Reading, Allentown, Bethlehem, Easton, 
Media, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
852 AM EDT Mon Apr 22 2024

...FROST ADVISORY WILL EXPIRE AT 9 AM EDT THIS MORNING...

The Frost Advisory will be allowed to expire at 9 am. However,
another frost advisory may be needed for portions of the area for
later tonight into Tuesday morning.

$$

DEZ001-NJZ012-013-015>023-027-221400-
/O.EXP.KPHI.FR.Y.0003.000000T0000Z-240422T1300Z/
New Castle-Middlesex-Western Monmouth-Mercer-Salem-Gloucester-
Camden-Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-
Including the cities of Wilmington, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
and Wharton State Forest
852 AM EDT Mon Apr 22 2024

...FROST ADVISORY WILL EXPIRE AT 9 AM EDT THIS MORNING...

The Frost Advisory will be allowed to expire at 9 am. However,
another frost advisory may be needed for portions of the area for
later tonight into Tuesday morning.

$$

Nearby

Frost Advisories in New Jersey, 2024Frost Advisories in Pennsylvania, 2024Frost Advisories in Delaware, 2024Every frost advisory in 2024

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.