Alert archive / New Jersey / Freeze Warnings in 2020

Freeze Warning 4, NWS Philadelphia/Mount Holly

April 21, 20204 states

NWS Philadelphia/Mount Holly issued this freeze warning at Apr 21, 2020, 3:34 AM EDT for 4 states. It took effect at Apr 22, 2020, 2:00 AM EDT. It was in force for 6 hr. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Apr 21, 2020, 3:34 AM EDT (07:34 UTC)
In effect from
Apr 22, 2020, 2:00 AM EDT
Expired
Apr 22, 2020, 8:00 AM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly
All 32 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Cecil County, MD, Kent County, MD, Queen Anne's County, MD, Talbot County, MD, 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, Philadelphia County, PA

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 00:00Z, 7.6 hours before the alert went out and 217 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, Washington/Dulle, VA at 00:00Z on 2020-04-21Temperature 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, Washington/Dulle, VA at 00:00Z on 2020-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 75 square meters per square second.19395878Sfc1 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
1797 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
75 m²/s²
0-3 km storm-relative helicity
157 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

450 
WWUS71 KPHI 210734
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
334 AM EDT Tue Apr 21 2020

DEZ001-MDZ008-NJZ001-007>010-012-013-015>023-027-PAZ060>062-070-
071-101>106-212200-
/O.NEW.KPHI.FZ.W.0004.200422T0600Z-200422T1200Z/
New Castle-Cecil-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Wharton State Forest, Reading, Allentown, Bethlehem, Easton, 
Media, Philadelphia, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
334 AM EDT Tue Apr 21 2020

...FREEZE WARNING IN EFFECT FROM 2 AM TO 8 AM EDT WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as the upper 20s and 
  lower 30s are expected.

* WHERE...The Lehigh Valley and southeastern Pennsylvania, much 
  of New Jersey, northern Delaware and extreme northeastern 
  Maryland. 

* WHEN...From 2:00 AM until 8:00 AM Wednesday.

* IMPACTS...Freezing conditions could kill sensitive plants.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect sensitive plants from the cold.

&&

$$

Iovino
3 follow-up statements
358 
WWUS71 KPHI 211934
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
334 PM EDT Tue Apr 21 2020

DEZ002-003-MDZ012-015-019-020-221000-
/O.EXA.KPHI.FZ.W.0004.200422T0600Z-200422T1200Z/
Kent-Inland Sussex-Kent MD-Queen Annes-Talbot-Caroline-
Including the cities of Dover, Georgetown, Chestertown, 
Centreville, Easton, and Denton
334 PM EDT Tue Apr 21 2020

...FREEZE WARNING IN EFFECT FROM 2 AM TO 8 AM EDT WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as the upper 20s and 
  lower 30s are expected.

* WHERE...Northeast Maryland. Central and southern Delaware. 

* WHEN...From 2:00 AM until 8:00 AM Wednesday.

* IMPACTS...Freezing conditions could kill sensitive plants.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$

DEZ001-MDZ008-NJZ001-007>010-012-013-015>023-027-PAZ060>062-070-
071-101>106-221000-
/O.CON.KPHI.FZ.W.0004.200422T0600Z-200422T1200Z/
New Castle-Cecil-Sussex-Warren-Morris-Hunterdon-Somerset-
Middlesex-Western Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Elkton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Wharton State Forest, Reading, Allentown, Bethlehem, Easton, 
Media, Philadelphia, Honey Brook, Oxford, West Chester, 
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Chalfont, Perkasie, Morrisville, and Doylestown
334 PM EDT Tue Apr 21 2020

...FREEZE WARNING REMAINS IN EFFECT FROM 2 AM TO 8 AM EDT
WEDNESDAY...

* WHAT...Sub-freezing temperatures as low as the upper 20s and 
  lower 30s are expected.

* WHERE...The Lehigh Valley and southeastern Pennsylvania, much 
  of New Jersey, northern Delaware and extreme northeastern 
  Maryland.

* WHEN...From 2:00 AM until 8:00 AM Wednesday.

* IMPACTS...Freezing conditions could kill sensitive plants.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
713 
WWUS71 KPHI 220720
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
320 AM EDT Wed Apr 22 2020

DEZ001>003-MDZ008-012-015-019-020-NJZ001-007>010-012-013-015>023-
027-PAZ060>062-070-071-101>106-221200-
/O.CON.KPHI.FZ.W.0004.000000T0000Z-200422T1200Z/
New Castle-Kent-Inland Sussex-Cecil-Kent MD-Queen Annes-Talbot-
Caroline-Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, Elkton, 
Chestertown, Centreville, Easton, Denton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Wharton State Forest, Reading, Allentown, Bethlehem, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
320 AM EDT Wed Apr 22 2020

...FREEZE WARNING REMAINS IN EFFECT UNTIL 8 AM EDT THIS MORNING...

* WHAT...Sub-freezing temperatures as low as the upper 20s and
  lower 30s are expected.

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

* WHEN...Until 8 AM EDT this morning.

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
381 
WWUS71 KPHI 221201
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
801 AM EDT Wed Apr 22 2020

DEZ001>003-MDZ008-012-015-019-020-NJZ001-007>010-012-013-015>023-
027-PAZ060>062-070-071-101>106-221315-
/O.EXP.KPHI.FZ.W.0004.000000T0000Z-200422T1200Z/
New Castle-Kent-Inland Sussex-Cecil-Kent MD-Queen Annes-Talbot-
Caroline-Sussex-Warren-Morris-Hunterdon-Somerset-Middlesex-
Western Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-Cape May-
Southeastern Burlington-Berks-Lehigh-Northampton-Delaware-
Philadelphia-Western Chester-Eastern Chester-Western Montgomery-
Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, Elkton, 
Chestertown, Centreville, Easton, Denton, Newton, Washington, 
Morristown, Flemington, Somerville, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Cape May Court House,
Wharton State Forest, Reading, Allentown, Bethlehem, Media, 
Philadelphia, Honey Brook, Oxford, West Chester, Kennett Square, 
Collegeville, Pottstown, Norristown, Lansdale, Chalfont, 
Perkasie, Morrisville, and Doylestown
801 AM EDT Wed Apr 22 2020

...FREEZE WARNING HAS EXPIRED...

Temperatures are above freezing across the area. Therefore, the
freeze warning was allowed to expire.

$$

CMS

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 21, 1:38 PM EDTSpecial Weather StatementPHINew Castle52 min
Apr 21, 1:49 PM EDTSevere Thunderstorm WarningPHIKent, New Castle56 min
Apr 21, 2:04 PM EDTSevere Thunderstorm WarningPHIKent, New Castle, Sussex56 min
Apr 21, 2:46 PM EDTSevere Thunderstorm WarningPHIKent, New Castle, Sussex74 min
Apr 21, 12:48 PM EDTSpecial Weather StatementPHIBucks, Chester, Montgomery42 min
Apr 21, 1:04 PM EDTSevere Thunderstorm WarningPHIBucks, Chester, Delaware, Montgomery, Northampton, Philadelphia26 min
Apr 21, 1:28 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia32 min
Apr 21, 1:59 PM EDTSevere Thunderstorm WarningPHIBucks, Montgomery, Philadelphia61 min
Apr 21, 11:44 AM EDTCoastal Flood StatementPHIOcean5 hr
Apr 21, 12:23 PM EDTSpecial Weather StatementPHIMonmouth37 min
Apr 21, 2:17 PM EDTSpecial Marine WarningPHI58 min
Apr 21, 2:24 PM EDTSevere Thunderstorm WarningPHIAtlantic, Burlington, Camden, Cape May, Cumberland, Gloucester and 2 more66 min
Apr 21, 2:55 PM EDTSevere Thunderstorm WarningPHIBurlington, Monmouth, Ocean35 min
Apr 21, 3:04 PM EDTSpecial Marine WarningPHI116 min

Nearby

Freeze Warnings in New Jersey, 2020Freeze Warnings in Pennsylvania, 2020Freeze Warnings in Maryland, 2020Every freeze warning in 2020

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.