Alert archive / Delaware / Frost Advisories in 2021

Frost Advisory 4, NWS Philadelphia/Mount Holly

November 5, 2021Sussex County, Delaware

NWS Philadelphia/Mount Holly issued this frost advisory at Nov 5, 2021, 2:36 PM EDT for Sussex County, Delaware. It took effect at Nov 6, 2021, 12:00 AM EDT. It was in force for 9 hr.

The area

The counties it named.

The facts

Issued
Nov 5, 2021, 2:36 PM EDT (18:36 UTC)
In effect from
Nov 6, 2021, 12:00 AM EDT
Expired
Nov 6, 2021, 9:00 AM EDT
In force
9 hr
Issued by
NWS Philadelphia/Mount Holly

County Sussex County, DE

The radar

The Dover AFB radar (KDOX), 18 km from the middle of the area, began a volume at 18:33 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, 6.6 hours before the alert went out and 84 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 2021-11-05Temperature 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 2021-11-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 square meters per square second.1939587897117Sfc1 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
1472 m above ground
0-6 km bulk shear
57 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
161 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

581 
WWUS71 KPHI 051836
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
236 PM EDT Fri Nov 5 2021

DEZ003-060900-
/O.NEW.KPHI.FR.Y.0004.211106T0400Z-211106T1300Z/
Inland Sussex-
Including the city of Georgetown
236 PM EDT Fri Nov 5 2021

...FROST ADVISORY IN EFFECT FROM MIDNIGHT TONIGHT TO 9 AM EDT
SATURDAY...

* WHAT...Temperatures as low as 32 will result in frost 
  formation.

* WHERE...Inland Sussex.

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

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

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Take steps now to protect tender plants from the cold.

&&

$$
2 follow-up statements
719 
WWUS71 KPHI 060716
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
316 AM EDT Sat Nov 6 2021

DEZ003-061300-
/O.CON.KPHI.FR.Y.0004.000000T0000Z-211106T1300Z/
Inland Sussex-
Including the city of Georgetown
316 AM EDT Sat Nov 6 2021

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

* WHAT...Temperatures as low as 29 will result in frost 
  formation.

* WHERE...Inland Sussex.

* 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.

&&

$$

MPS
021 
WWUS71 KPHI 061254
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
854 AM EDT Sat Nov 6 2021

DEZ003-061400-
/O.EXP.KPHI.FR.Y.0004.000000T0000Z-211106T1300Z/
Inland Sussex-
Including the city of Georgetown
854 AM EDT Sat Nov 6 2021

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

Temperatures will continue to rise through the morning. Therefore,
the frost advisory will be allowed to expire.

$$

Johnson

Nearby

Frost Advisories in Delaware, 2021Every frost advisory 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.