Calamity
mediumSevere weatherCalamity Score: 52

Severe Weather near Greater Upper Marlboro

CalvertUnited StatesNOAA

This alert expired on 5 July 2026 at 00:30 UTC. It is kept here as a record.

It is the 7th strongest of the 160 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 8 more were recorded here in the fortnight before it.

What the source measured

NOAA reported: Special Marine Warning issued July 4 at 6:35PM EDT until July 4 at 8:30PM EDT by NWS Baltimore MD/Washington DC

An estimated 3,158,930 people live within 50 km of this point.

Nearby, since 16 March 2026

How we know

Confirmed by 2 independent sources, including NOAA.

Our own score for this event is 52 out of 100, at 83 % confidence.

The score is ours, computed from intensity, exposed population and local history — not the source’s.

Event Data

TypeSevere weather
Severitymedium
Calamity Score (ours)52 / 100
Our confidence83%
Coordinates38.6987, -76.6888
Nearest CityGreater Upper Marlboro (16 km)
Population Exposed3.2M within 50 km
Impact Tiersignificant
Timestamp2026-07-04T22:35:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.331f3a4b944f799598eaadf2f6a47981

Score Breakdown

35
intensity
100
population
0
cascading
80
historical

Technical Details

EventSpecial Marine Warning
UrgencyImmediate
CertaintyLikely
AreaDescChesapeake Bay from Pooles Island to Sandy Point MD; Chesapeake Bay from Sandy Point to North Beach MD; Chesapeake Bay from North Beach to Drum Point MD; Chesapeake Bay from Drum Point MD to Smith Point VA; Chester River to Queenstown MD; Eastern Bay; Choptank River to Cambridge MD and the Little Choptank River; Patuxent River to Broomes Island MD; Tangier Sound and the inland waters surrounding Bloodsworth Island; Chesapeake Bay north of Pooles Island MD; Chesapeake Bay from Pooles Island to Sandy Point MD; Chesapeake Bay from Sandy Point to North Beach MD; Patapsco River including Baltimore Harbor; Chester River to Queenstown MD; Tidal Potomac from Indian Head to Cobb Island MD; Tidal Potomac from Cobb Island MD to Smith Point VA and 1 more areas
HeadlineSpecial Marine Warning issued July 4 at 6:35PM EDT until July 4 at 8:30PM EDT by NWS Baltimore MD/Washington DC
Expires2026-07-04T20:30:00-04:00
SenderNameNWS Baltimore MD/Washington DC
HasExactCoordstrue
MergedCount4
MergedIds["noaa_urn:oid:2.49.0.1.840.0.331f3a4b944f799598eaadf2f6a479815eaeb569.002.1","noaa_urn:oid:2.49.0.1.840.0.e26c56522c29f2b37991b8009dd493ac4d64ddc2.001.1","noaa_urn:oid:2.49.0.1.840.0.b402cb13deba1cd9bab2fb8a2a56bdd4d544436c.001.1","noaa_urn:oid:2.49.0.1.840.0.6b9144f890a268885cddd75e1c309fc3a5a4fd49.001.1"]
Iem TypeSummaryM
Iem Magnitude55
Iem Unitmph
Iem CityQuantico Marine Corp
Iem CountyPrince William
Iem StateVA
Iem WfoLWX
Iem RemarkA wind gust of 48 knots (55 MPH) was measured by the AWOS at Quantico Marine Base (KNYG) adjacent to the tidal Potomac River.
MergedSources[{"id":"iem_M_38.510_-77.300_1783201800000","source":"iem","severity":"low","severityValue":25,"timestamp":1783201800000,"latitude":38.51,"longitude":-77.3}]

Safety Information

Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.

Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.

This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.

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Calamity.live data shows a weather event with CalamityScore 52/100, near Greater Upper Marlboro (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.