Alert archive / New Jersey / Dense Fog Advisories in 2021

Dense Fog Advisory 7, NWS Philadelphia/Mount Holly

October 14, 20214 states

NWS Philadelphia/Mount Holly issued this dense fog advisory at Oct 14, 2021, 3:16 AM EDT for 4 states. It was in force for 3 hr.

The area

The counties it named.

The facts

Issued
Oct 14, 2021, 3:16 AM EDT (07:16 UTC)
Expired
Oct 14, 2021, 6:35 AM EDT
In force
3 hr
Issued by
NWS Philadelphia/Mount Holly
All 33 counties

Kent County, DE, New Castle County, DE, Sussex County, DE, Caroline 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, Carbon County, PA, Chester County, PA, Delaware County, PA, Lehigh County, PA, Monroe County, PA, Montgomery County, PA, Northampton County, PA, Philadelphia County, PA

The radar

The Philadelphia radar (KDIX), 67 km from the middle of the area, began a volume at 07:16 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 00:00Z, 7.3 hours before the alert went out and 220 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 00:00Z on 2021-10-14Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 joules per kilogram.LCLLFCEL10008507005003002001001 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 00:00Z on 2021-10-14The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 42 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
2 J/kg
Mixed-layer CIN
-2 J/kg
Mixed-layer LCL
601 m above ground
0-6 km bulk shear
43 kt
0-1 km storm-relative helicity
42 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

296 
WWUS71 KPHI 140716
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
316 AM EDT Thu Oct 14 2021

DEZ001>004-MDZ012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-070-071-101>106-141100-
/O.NEW.KPHI.FG.Y.0007.211014T0716Z-211014T1100Z/
New Castle-Kent-Inland Sussex-Delaware Beaches-Kent MD-
Queen Annes-Talbot-Caroline-Sussex-Warren-Morris-Hunterdon-
Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Ocean-Cumberland-
Atlantic-Cape May-Atlantic Coastal Cape May-Coastal Atlantic-
Coastal Ocean-Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-
Northampton-Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Chestertown, Centreville, Easton, Denton, Newton,
Washington, Morristown, Flemington, Somerville, New Brunswick, 
Freehold, Sandy Hook, Trenton, Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Jackson, Millville, 
Hammonton, Cape May Court House, Ocean City, Atlantic City, 
Long Beach Island, Wharton State Forest, Jim Thorpe, Stroudsburg,
Reading, Allentown, Bethlehem, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
316 AM EDT Thu Oct 14 2021

...DENSE FOG ADVISORY IN EFFECT UNTIL 7 AM EDT THIS MORNING...

* WHAT...Visibility as low as 1/4 mile in dense fog.

* WHERE...Portions of New Jersey, southeast Pennsylvania, 
  Delaware, and the eastern shores of Maryland.

* WHEN...Until 7 AM EDT this morning.

* IMPACTS...Hazardous driving conditions due to low visibility.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If driving, slow down, use your headlights, and leave plenty of
distance ahead of you.

&&

$$

MPS
1 follow-up statement
278 
WWUS71 KPHI 141035
NPWPHI

URGENT - WEATHER MESSAGE
National Weather Service Mount Holly NJ
635 AM EDT Thu Oct 14 2021

DEZ001>004-MDZ012-015-019-020-NJZ001-007>010-012>027-PAZ054-055-
060>062-070-071-101>106-141145-
/O.CAN.KPHI.FG.Y.0007.000000T0000Z-211014T1100Z/
New Castle-Kent-Inland Sussex-Delaware Beaches-Kent MD-
Queen Annes-Talbot-Caroline-Sussex-Warren-Morris-Hunterdon-
Somerset-Middlesex-Western Monmouth-Eastern Monmouth-Mercer-Salem-
Gloucester-Camden-Northwestern Burlington-Ocean-Cumberland-
Atlantic-Cape May-Atlantic Coastal Cape May-Coastal Atlantic-
Coastal Ocean-Southeastern Burlington-Carbon-Monroe-Berks-Lehigh-
Northampton-Delaware-Philadelphia-Western Chester-Eastern Chester-
Western Montgomery-Eastern Montgomery-Upper Bucks-Lower Bucks-
Including the cities of Wilmington, Dover, Georgetown, 
Rehoboth Beach, Chestertown, Centreville, Easton, Denton, Newton,
Washington, Morristown, Flemington, Somerville, New Brunswick, 
Freehold, Sandy Hook, Trenton, Pennsville, Glassboro, Camden, 
Cherry Hill, Moorestown, Mount Holly, Jackson, Millville, 
Hammonton, Cape May Court House, Ocean City, Atlantic City, 
Long Beach Island, Wharton State Forest, Jim Thorpe, Stroudsburg,
Reading, Allentown, Bethlehem, Media, Philadelphia, Honey Brook, 
Oxford, West Chester, Kennett Square, Collegeville, Pottstown, 
Norristown, Lansdale, Chalfont, Perkasie, Morrisville, 
and Doylestown
635 AM EDT Thu Oct 14 2021

...DENSE FOG ADVISORY IS CANCELLED...

The dense fog is beginning to lift, and visibilities are
increasing to over one-quarter mile. Therefore, the Dense Fog 
Advisory has been cancelled.

$$

MPS

Nearby

Dense Fog Advisories in New Jersey, 2021Dense Fog Advisories in Pennsylvania, 2021Dense Fog Advisories in Maryland, 2021Every dense fog 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.