Alert archive / Pennsylvania / Frost Advisories in 2020

Frost Advisory 10, NWS Philadelphia/Mount Holly

September 20, 2020Sussex County, Warren County, New Jersey; 4 counties in Pennsylvania

NWS Philadelphia/Mount Holly issued this frost advisory at Sep 20, 2020, 3:16 PM EDT for Sussex County, Warren County, New Jersey; 4 counties in Pennsylvania. It took effect at Sep 21, 2020, 1:00 AM EDT. It was in force for 5 hr.

The area

The counties it named.

The facts

Issued
Sep 20, 2020, 3:16 PM EDT (19:16 UTC)
In effect from
Sep 21, 2020, 1:00 AM EDT
Expired
Sep 21, 2020, 5:49 AM EDT
In force
5 hr
Issued by
NWS Philadelphia/Mount Holly

Counties Sussex County, NJ, Warren County, NJ, Carbon County, PA, Lehigh County, PA, Monroe County, PA, Northampton County, PA

The radar

The Philadelphia radar (KDIX), 128 km from the middle of the area, began a volume at 19:15 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 202 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 2020-09-20Temperature 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, Brookhaven, NY at 12:00Z on 2020-09-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -104 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
1455 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
-104 m²/s²
0-3 km storm-relative helicity
-56 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

931 
WWUS71 KPHI 201916
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
316 PM EDT Sun Sep 20 2020

NJZ001-007-PAZ054-055-061-062-211000-
/O.NEW.KPHI.FR.Y.0010.200921T0500Z-200921T1200Z/
Sussex-Warren-Carbon-Monroe-Lehigh-Northampton-
Including the cities of Newton, Washington, Jim Thorpe, 
Stroudsburg, Allentown, Bethlehem, and Easton
316 PM EDT Sun Sep 20 2020

...FROST ADVISORY IN EFFECT FROM 1 AM TO 8 AM EDT MONDAY...

* WHAT...Temperatures as low as 35 to 37 degrees will result in 
  frost formation.

* WHERE...In New Jersey, Sussex and Warren. In Pennsylvania, 
  Carbon, Monroe, Lehigh and Northampton.

* WHEN...From 1 AM to 8 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
1 follow-up statement
868 
WWUS71 KPHI 210949
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
549 AM EDT Mon Sep 21 2020

NJZ001-007-PAZ054-055-061-062-211100-
/O.CAN.KPHI.FR.Y.0010.000000T0000Z-200921T1200Z/
Sussex-Warren-Carbon-Monroe-Lehigh-Northampton-
Including the cities of Newton, Washington, Jim Thorpe, 
Stroudsburg, Allentown, Bethlehem, and Easton
549 AM EDT Mon Sep 21 2020

...FROST ADVISORY IS CANCELLED...

Temperatures will warm up quickly this morning with daybreak and
thus no additional frost is expected to form through the morning.

$$

Deal

Nearby

Frost Advisories in Pennsylvania, 2020Frost Advisories in New Jersey, 2020Every frost advisory 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; radar from the NEXRAD Level II archive.