Alert archive / New Jersey / Frost Advisories in 2018

Frost Advisory 1, NWS Philadelphia/Mount Holly

April 20, 20184 states

NWS Philadelphia/Mount Holly issued this frost advisory at Apr 20, 2018, 3:35 PM EDT for 4 states. It took effect at Apr 21, 2018, 2:00 AM EDT. It was in force for 6 hr.

The area

The counties it named.

The facts

Issued
Apr 20, 2018, 3:35 PM EDT (19:35 UTC)
In effect from
Apr 21, 2018, 2:00 AM EDT
Expired
Apr 21, 2018, 8:00 AM EDT
In force
6 hr
Issued by
NWS Philadelphia/Mount Holly

Counties Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline County, MD, Kent County, MD, Queen Anne's County, MD, Atlantic County, NJ, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Mercer County, NJ, Middlesex County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Montgomery County, PA

The radar

The Philadelphia radar (KDIX), 72 km from the middle of the area, began a volume at 19:34 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 7.6 hours before the alert went out and 194 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, Wallops Is Stn, VA at 12:00Z on 2018-04-20Temperature 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, Wallops Is Stn, VA at 12:00Z on 2018-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -47 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
1459 m above ground
0-6 km bulk shear
60 kt
0-1 km storm-relative helicity
-47 m²/s²
0-3 km storm-relative helicity
33 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

953 
WWUS71 KPHI 201935
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
335 PM EDT Fri Apr 20 2018

MDZ008-PAZ060-101-103-210745-
/O.NEW.KPHI.FZ.W.0003.180421T0600Z-180421T1200Z/
Cecil-Berks-Western Chester-Western Montgomery-
Including the cities of Elkton, Reading, Honey Brook, Oxford, 
Collegeville, and Pottstown
335 PM EDT Fri Apr 20 2018

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

The National Weather Service in Mount Holly has issued a Freeze
Warning, which is in effect from 2 AM to 8 AM EDT Saturday.

* TEMPERATURES...Lows 30 to 32 degrees early Saturday morning.

* IMPACTS...Frost and freeze conditions may damage sensitive 
  vegetation. Take steps now to protect tender plants from the 
  cold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Freeze Warning means sub-freezing temperatures are imminent or
highly likely. These conditions will kill crops and other
sensitive vegetation.

&&

$$

DEZ001>003-MDZ012-015-020-NJZ012-013-015>022-027-PAZ102-104-106-
210745-
/O.NEW.KPHI.FR.Y.0001.180421T0600Z-180421T1200Z/
New Castle-Kent-Inland Sussex-Kent MD-Queen Annes-Caroline-
Middlesex-Western Monmouth-Mercer-Salem-Gloucester-Camden-
Northwestern Burlington-Ocean-Cumberland-Atlantic-
Southeastern Burlington-Eastern Chester-Eastern Montgomery-
Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Chestertown, Centreville, Denton, New Brunswick, Freehold, 
Trenton, Pennsville, Glassboro, Camden, Cherry Hill, Moorestown, 
Mount Holly, Jackson, Millville, Hammonton, Wharton State Forest,
West Chester, Kennett Square, Norristown, Lansdale, Morrisville, 
and Doylestown
335 PM EDT Fri Apr 20 2018

...FROST ADVISORY IN EFFECT FROM 2 AM TO 8 AM EDT SATURDAY...

The National Weather Service in Mount Holly has issued a Frost
Advisory, which is in effect from 2 AM to 8 AM EDT Saturday.

* TEMPERATURES...Lows in the mid 30s early Saturday morning will
  allow for frost to develop.

* IMPACTS...Frost conditions may damage sensitive vegetation. 
  Take steps now to protect tender plants from the cold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Frost Advisory means that widespread frost is expected.
Sensitive outdoor plants may be killed if left uncovered.

&&

$$
2 follow-up statements
427 
WWUS71 KPHI 210634
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
234 AM EDT Sat Apr 21 2018

NJZ012-013-015-019-020-022-027-PAZ102-104-106-211200-
/O.UPG.KPHI.FR.Y.0001.000000T0000Z-180421T1200Z/
/O.EXA.KPHI.FZ.W.0003.000000T0000Z-180421T1200Z/
Middlesex-Western Monmouth-Mercer-Northwestern Burlington-Ocean-
Atlantic-Southeastern Burlington-Eastern Chester-
Eastern Montgomery-Lower Bucks-
Including the cities of New Brunswick, Freehold, Trenton, 
Moorestown, Mount Holly, Jackson, Hammonton, 
Wharton State Forest, West Chester, Kennett Square, Norristown, 
Lansdale, Morrisville, and Doylestown
234 AM EDT Sat Apr 21 2018

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

The National Weather Service in Mount Holly has issued a Freeze
Warning, which is in effect until 8 AM EDT this morning. The
Frost Advisory is no longer in effect.

* TEMPERATURES...In the lower 30s. Colder spots may reach the
  upper 20s.

* IMPACTS...Frost and freeze conditions may damage sensitive 
  vegetation. Take steps now to protect tender plants from the 
  cold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Freeze Warning means sub-freezing temperatures are imminent or
highly likely. These conditions will kill crops and other
sensitive vegetation.

&&

$$

MDZ008-PAZ060-101-103-211200-
/O.CON.KPHI.FZ.W.0003.000000T0000Z-180421T1200Z/
Cecil-Berks-Western Chester-Western Montgomery-
Including the cities of Elkton, Reading, Honey Brook, Oxford, 
Collegeville, and Pottstown
234 AM EDT Sat Apr 21 2018

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

* TEMPERATURES...In the lower 30s. Colder spots may reach the
  upper 20s.

* IMPACTS...Frost and freeze conditions may damage sensitive 
  vegetation. Take steps now to protect tender plants from the 
  cold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Freeze Warning means sub-freezing temperatures are imminent or
highly likely. These conditions will kill crops and other
sensitive vegetation.

&&

$$

DEZ001>003-MDZ012-015-020-NJZ016>018-021-211200-
/O.CON.KPHI.FR.Y.0001.000000T0000Z-180421T1200Z/
New Castle-Kent-Inland Sussex-Kent MD-Queen Annes-Caroline-Salem-
Gloucester-Camden-Cumberland-
Including the cities of Wilmington, Dover, Georgetown, 
Chestertown, Centreville, Denton, Pennsville, Glassboro, Camden, 
Cherry Hill, and Millville
234 AM EDT Sat Apr 21 2018

...FROST ADVISORY REMAINS IN EFFECT UNTIL 8 AM EDT THIS MORNING...

* TEMPERATURES...In the mid to upper 30s.

* IMPACTS...Frost and freeze conditions may damage sensitive 
  vegetation. Take steps now to protect tender plants from the 
  cold.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Frost Advisory means that widespread frost is expected.
Sensitive outdoor plants may be killed if left uncovered.

&&

$$

CMS
912 
WWUS71 KPHI 211150
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
750 AM EDT Sat Apr 21 2018

MDZ008-NJZ012-013-015-019-020-022-027-PAZ060-101>104-106-211300-
/O.EXP.KPHI.FZ.W.0003.000000T0000Z-180421T1200Z/
Cecil-Middlesex-Western Monmouth-Mercer-Northwestern Burlington-
Ocean-Atlantic-Southeastern Burlington-Berks-Western Chester-
Eastern Chester-Western Montgomery-Eastern Montgomery-Lower Bucks-
Including the cities of Elkton, New Brunswick, Freehold, Trenton,
Moorestown, Mount Holly, Jackson, Hammonton, 
Wharton State Forest, Reading, Honey Brook, Oxford, West Chester,
Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, 
Morrisville, and Doylestown
750 AM EDT Sat Apr 21 2018

...FREEZE WARNING WILL EXPIRE AT 8 AM EDT THIS MORNING...

Temperatures are above freezing and will continue to rise through
the morning, therefore the freeze warning will be allowed to
expire.

$$

DEZ001>003-MDZ012-015-020-NJZ016>018-021-211300-
/O.EXP.KPHI.FR.Y.0001.000000T0000Z-180421T1200Z/
New Castle-Kent-Inland Sussex-Kent MD-Queen Annes-Caroline-Salem-
Gloucester-Camden-Cumberland-
Including the cities of Wilmington, Dover, Georgetown, 
Chestertown, Centreville, Denton, Pennsville, Glassboro, Camden, 
Cherry Hill, and Millville
750 AM EDT Sat Apr 21 2018

...FROST ADVISORY WILL EXPIRE AT 8 AM EDT THIS MORNING...

Temperatures continue to rise this morning and therefore the frost
advisory will be allowed to expire.

$$

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 20, 3:35 PM EDTFreeze WarningPHIBerks, Bucks, Chester, Montgomery16 hr

Nearby

Frost Advisories in New Jersey, 2018Frost Advisories in Pennsylvania, 2018Frost Advisories in Delaware, 2018Every frost advisory in 2018

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.