Alert archive / Pennsylvania / Dense Fog Advisories in 2021
Dense Fog Advisory 6, NWS Philadelphia/Mount Holly
NWS Philadelphia/Mount Holly issued this dense fog advisory at Oct 3, 2021, 3:33 AM EDT for 4 states. It took effect at Oct 3, 2021, 4:00 AM EDT. It was in force for 6 hr.
The area
The counties it named.
The facts
- Issued
- Oct 3, 2021, 3:33 AM EDT (07:33 UTC)
- In effect from
- Oct 3, 2021, 4:00 AM EDT
- Expired
- Oct 3, 2021, 10:00 AM EDT
- In force
- 6 hr
- Issued by
- NWS Philadelphia/Mount Holly
Counties New Castle County, DE, Kent County, MD, Gloucester County, NJ, Salem County, NJ, Bucks County, PA, Chester County, PA, Delaware County, PA, Montgomery County, PA
The radar
The Philadelphia radar (KDIX), 93 km from the middle of the area, began a volume at 07:35 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
Washington/Dulle, VA (KIAD), launched 00:00Z, 7.6 hours before the alert went out and 191 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1601 m above ground
- 0-6 km bulk shear
- 25 kt
- 0-1 km storm-relative helicity
- 63 m²/s²
- 0-3 km storm-relative helicity
- 79 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
908 WWUS71 KPHI 030733 NPWPHI URGENT - WEATHER MESSAGE National Weather Service Mount Holly NJ 333 AM EDT Sun Oct 3 2021 PAZ070-101>106-031400- /O.NEW.KPHI.FG.Y.0006.211003T0800Z-211003T1400Z/ Delaware-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Media, Honey Brook, Oxford, West Chester, Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville, and Doylestown 333 AM EDT Sun Oct 3 2021 ...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM EDT THIS MORNING... * WHAT...Visibility near or below one quarter mile in dense fog. * WHERE...Delaware, Western Chester, Eastern Chester, Western Montgomery, Eastern Montgomery, Upper Bucks and Lower Bucks. * WHEN...Until 10 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. && $$ Johnson
2 follow-up statements
712 WWUS71 KPHI 030907 NPWPHI URGENT - WEATHER MESSAGE National Weather Service Mount Holly NJ 507 AM EDT Sun Oct 3 2021 DEZ001-MDZ012-NJZ016-017-031400- /O.EXA.KPHI.FG.Y.0006.000000T0000Z-211003T1400Z/ New Castle-Kent MD-Salem-Gloucester- Including the cities of Wilmington, Chestertown, Pennsville, and Glassboro 507 AM EDT Sun Oct 3 2021 ...DENSE FOG ADVISORY IN EFFECT UNTIL 10 AM EDT THIS MORNING... * WHAT...Visibility near or below one quarter mile in dense fog. * WHERE...In New Jersey, Salem and Gloucester. In Maryland, Kent MD. In Delaware, New Castle. * WHEN...Until 10 AM EDT this morning. * IMPACTS...Hazardous driving conditions due to low visibility. PRECAUTIONARY/PREPAREDNESS ACTIONS... If driving, slow down, use your headlights, and leave plenty of distance ahead of you. && $$ PAZ070-101>106-031400- /O.CON.KPHI.FG.Y.0006.000000T0000Z-211003T1400Z/ Delaware-Western Chester-Eastern Chester-Western Montgomery- Eastern Montgomery-Upper Bucks-Lower Bucks- Including the cities of Media, Honey Brook, Oxford, West Chester, Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville, and Doylestown 507 AM EDT Sun Oct 3 2021 ...DENSE FOG ADVISORY REMAINS IN EFFECT UNTIL 10 AM EDT THIS MORNING... * WHAT...Visibility near or below one quarter mile in dense fog. * WHERE...Delaware, Eastern Montgomery, Upper Bucks, Lower Bucks, Western Chester, Eastern Chester and Western Montgomery. * WHEN...Until 10 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. && $$
094 WWUS71 KPHI 031351 NPWPHI URGENT - WEATHER MESSAGE National Weather Service Mount Holly NJ 951 AM EDT Sun Oct 3 2021 DEZ001-MDZ012-NJZ016-017-PAZ070-101>106-031500- /O.EXP.KPHI.FG.Y.0006.000000T0000Z-211003T1400Z/ New Castle-Kent MD-Salem-Gloucester-Delaware-Western Chester- Eastern Chester-Western Montgomery-Eastern Montgomery-Upper Bucks- Lower Bucks- Including the cities of Wilmington, Chestertown, Pennsville, Glassboro, Media, Honey Brook, Oxford, West Chester, Kennett Square, Collegeville, Pottstown, Norristown, Lansdale, Chalfont, Perkasie, Morrisville, and Doylestown 951 AM EDT Sun Oct 3 2021 ...DENSE FOG ADVISORY WILL EXPIRE AT 10 AM EDT THIS MORNING... The dense fog is lifting and dissipating across the region this morning. While a few spots may remain denser than others, visibilities have increased to greater than one quarter mile through much of the region. Therefore, the dense fog advisory will be allowed to expire. $$ Meola
The office that day
Everything else NWS Philadelphia/Mount Holly issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Oct 3, 5:08 AM EDT | Marine Dense Fog Advisory | PHI | 5 hr |
Nearby
Dense Fog Advisories in Pennsylvania, 2021Dense Fog Advisories in New Jersey, 2021Dense Fog Advisories in Delaware, 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.