Dense Fog in Pennsylvania, March 12, 2026

Name: Dense Fog in Pennsylvania, March 12, 2026
Start: 2026-03-12T00:00
End: 2026-03-12T06:00
Location: Pennsylvania

March 12, 2026 · NWS PHI · 3 events in 3 counties and zones

A warm front advancing northward over cold ground helped cause widespread fog to form early on March 12th. The fog dissipated by dawn.

Where it happened

Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 3

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS PHI wrote it up.

A warm front advancing northward over cold ground helped cause widespread fog to form early on March 12th. The fog dissipated by dawn.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Philadelphia/Mount Holly wrote its last area forecast discussion before the first event at Mar 11, 9:08 PM EST, 2 hours 52 minutes earlier.

Area forecast discussion, Mar 11, 9:08 PM EST, 2 hours 52 minutes before

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Hazardous weather outlook, Mar 11, 4:08 AM EST, 19 hours 52 minutes before

Hazardous Weather Outlook
National Weather Service Mount Holly NJ
508 AM EDT Wed Mar 11 2026

MDZ012-015-019-020-120915-
Kent MD-Queen Annes-Talbot-Caroline-
508 AM EDT Wed Mar 11 2026

This Hazardous Weather Outlook is for northeast Maryland.

.DAY ONE...Today and tonight.

Scattered severe thunderstorms are possible later this afternoon into
early this evening. Most likely timing is between 3 PM and 10 PM.
Severe thunderstorms may be capable of locally damaging straight line
wind gusts up to 60 to 70 mph. Hail up to quarter-size and an
isolated tornado is possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday.

The probability for widespread hazardous weather is low.

.SPOTTER INFORMATION STATEMENT...

Weather spotters are encouraged to report significant weather
conditions according to standard operating procedures.

DeSilva

In the hours before

Local storm report, Mar 11, 10:02 PM EST, 1 hour 58 minutes before

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Local storm report, Mar 11, 10:04 PM EST, 1 hour 56 minutes before

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Local storm report, Mar 11, 10:05 PM EST, 1 hour 55 minutes before

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Local storm report, Mar 11, 10:07 PM EST, 1 hour 53 minutes before

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Local storm report, Mar 11, 10:18 PM EST, 1 hour 42 minutes before

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Local storm report, Mar 11, 10:21 PM EST, 1 hour 39 minutes before

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The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

3 dense fog. Local standard time, as filed.

Dense Fog, Berks

When: March 12, 12:00 AM EST to 6:00 AM EST
Where: Berks forecast zone
Reported by: ASOS
Coordinates: 40.416, -75.926 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Reading Regional Airport.

Dense Fog, Upper Bucks

When: March 12, 12:00 AM EST to 6:00 AM EST
Where: Upper Bucks forecast zone
Reported by: AWOS
Coordinates: 40.337, -75.107 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Pennridge Airport and Quakertown Airport.

Dense Fog, Western Montgomery

When: March 12, 12:00 AM EST to 6:00 AM EST
Where: Western Montgomery forecast zone
Reported by: ASOS
Coordinates: 40.211, -75.367 (the zone’s center; the record gives no point)

Several hours of dense fog was observed at Heritage Field.

What these are

Dense Fog: Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Pennsylvania in 2026 Every state in 2026 This day in weather history Warnings in Pennsylvania, March 2026

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-10-01. Each event’s entry at NCEI: 1321726, 1321727, 1321728.