Scattered thunderstorms produced several instances of wind damage across northern Maryland, eastern West Virginia and northwestern Virginia.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS LWX wrote it up.
Scattered thunderstorms produced several instances of wind damage across northern Maryland, eastern West Virginia and northwestern Virginia.
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 Baltimore/Washington wrote its last area forecast discussion before the first event at Jul 12, 9:03 AM EST, 5 hours 2 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1003 AM EDT Mon Jul 12 2021 .SYNOPSIS... Bermuda high pressure system will build across the region through mid-week before weakening thereafter. A weakening cold front will fizzle to our north Wednesday, with another cold front poised to drop southward into the area this weekend. && .NEAR TERM /THROUGH TONIGHT/... Continued height rises today as mid-upper level ridge reaches maximum amplitude over the area this evening. As a result, temperatures will continue to trend upward today with highs about 5F warmer than yesterday with mid 90s expected east of the Blue Ridge. Model trends indicate sfc dewpoints will be about 2F degs lower than yesterday likely due to increasing subsidence, thus keeping heat indices just below advisory criteria in the 100-102 range for several hours. It may reach 105 briefly in localized spots especially along the Cheasapeake Bay, but advisory criteria is 105 for two hours or longer. As for thunderstorm potential, we're likely to see a decrease in convective coverage due to increasing subsidence/height rises. However, areas north of I-66 and Highway 50 should see scattered thunderstorms this afternoon and evening, some of which will become strong to severe. While much of the region aside from Nelson County VA and St. Marys County MD are in a Marginal risk for severe thunderstorms, the best threat would be north of those thoroughfare. Damaging winds would be the primary severe hazard to go with the typical torrential downpours and frequent lightning. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... Upper level ridge will begin to weaken on Tue as TUTT low over Florida gets caught up in the southwest flow aloft and tracks north northeastward, while mid-level ridge remains strong. This may result in sct afternoon convection mainly west of the Blue Ridge. Heights aloft will begin to weaken more steadily Tue night-Wed as a mid-upper level trough over the Great Lks and Midwest crosses the Mid-Atlantic states. Models indicate a more substantial increase in convection on Wednesday as a result and a few severe thunderstorms are likely due to the ample moisture and instability and strengthening flow aloft. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A shortwave trough will depart off to our northeast on Thursday, leaving us with shortwave ridging aloft in its wake. The presence of shortwave ridging will limit the coverage of afternoon/evening thunderstorm activity. Although a stray shower or storm can't be ruled out within the hot and humid airmass, most locations should remain dry. Temperatures on Thursday will max out in the upper 80s to lower 90s, with dewpoints in the upper 60s to lower 70s. Model guidance is in reasonably good agreement that mid-upper level troughing will become established off to our north and west by Friday. This trough will eventually drive a surface cold front southward toward our area by the upcoming weekend, leading to an increase in chances for afternoon showers and thunderstorms. Friday will feature greater chances for storms than Thursday, but it currently looks like the greatest chances for storms will come on Saturday as the front approaches from the northwest. There's a considerable amount of spread with respect the positioning of the parent trough and the associated surface front by Sunday. As a result, there's also a lot of spread with respect to the sensible weather forecast for Sunday. Some solutions have the front pressing to our south, which would lead to drier conditions locally. Other solutions hang up the front either overhead or to our northwest. This type of scenario would lead to continued chances for afternoon showers and thunderstorms. With multiple rounds of storms over the course of the week, locations that see storms several days in a row could experience isolated instances of flooding, but it is far too early to speculate on where this may occur. Conditions will remain hot and humid through at least Saturday, with temperatures maxing out in the lower to middle 90s each day, with dewpoints around 70. && .AVIATION /14Z MONDAY THROUGH FRIDAY/... Scattered thunderstorms are expected NW of the main terminals today with KMRB having the best chance of experiencing a t-storm. Elsewhere, thunderstorm risk will remain too low to even include a VCTS through Tuesday at this time. Thunderstorm chances increase substantially Wed with the approach of an upper-level trough. Prevailing VFR conditions are expected on both Thursday and Friday. Temporary drops to sub-VFR may be possible in association with any thunderstorms that form Friday afternoon. && .MARINE... SCA conditions expected again through tonight in srly flow. Winds weaken tonight through mid-week. SMWs may be required across the mid/upper Chesapeake Bay this afternoon and evening with any strong to severe thunderstorm. The risk of thunderstorms will increase on Wed where SMWs may be required. Prevailing sub-SCA level winds are expected on both Thursday and Friday. Gusty winds may be possible with any thunderstorms that form Friday afternoon. && .TIDES/COASTAL FLOODING... The semi-persistent southerly flow has led to a spike in tidal anomalies. Numbers have come down over the middle Chesapeake Bay, but remain elevated elsewhere. Some tidal sites may approach Action during the next few high tides. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ534-537-543. && SYNOPSIS...LFR NEAR TERM...LFR/BRO SHORT TERM...LFR LONG TERM...KJP AVIATION...LFR/BRO/KJP MARINE...LFR/BRO/KJP TIDES/COASTAL FLOODING...BRO
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 956 AM EDT Mon Jul 12 2021 ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508- VAZ052>057-131400- 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- Chesapeake Bay from North Beach to Drum Point MD- Chesapeake Bay from Drum Point MD to Smith Point VA- Tidal Potomac from Key Bridge to Indian Head MD- Tidal Potomac from Indian Head to Cobb Island MD- Tidal Potomac from Cobb Island MD to Smith Point VA- Patapsco River including Baltimore Harbor- 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-District of Columbia-Cecil-Southern Baltimore- Prince Georges-Anne Arundel-Charles-St. Marys-Calvert- Central and Southeast Montgomery-Central and Southeast Howard- Southeast Harford-Prince William/Manassas/Manassas Park-Fairfax- Arlington/Falls Church/Alexandria-Stafford-Spotsylvania- King George- 956 AM EDT Mon Jul 12 2021 This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and I-95 corridor through central Maryland, northern Virginia, and District of Columbia. .DAY ONE...Today and Tonight Isolated to scattered severe thunderstorms are possible this afternoon and evening with damaging wind gusts being the primary hazard. This may also require Special Marine Warnings across the middle to upper Chesapeake Bay waters. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Isolated severe thunderstorms with damaging wind gusts are possible Wednesday and Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is possible this afternoon and evening. MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508- WVZ050>053-055-131400- Washington-Frederick MD-Carroll-Northern Baltimore- Northwest Montgomery-Northwest Howard-Northwest Harford-Augusta- Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke-Nelson- Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper- Northern Fauquier-Southern Fauquier-Western Loudoun- Eastern Loudoun-Northern Virginia Blue Ridge- Central Virginia Blue Ridge-Hampshire-Morgan-Berkeley-Jefferson- Hardy- 956 AM EDT Mon Jul 12 2021 This Hazardous Weather Outlook is for portions of eastern West Virginia, northern and central Virginia, and central and western Maryland. .DAY ONE...Today and Tonight Isolated severe thunderstorms are possible this afternoon into early evening mainly west of U.S. Route 15 and across northern Maryland. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Isolated severe thunderstorms with damaging wind gusts are possible Wednesday and Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MDZ001-501-502-VAZ503-504-WVZ501>506-131400- Garrett-Extreme Western Allegany-Central and Eastern Allegany- Western Highland-Eastern Highland-Western Grant-Eastern Grant- Western Mineral-Eastern Mineral-Western Pendleton- Eastern Pendleton- 956 AM EDT Mon Jul 12 2021 This Hazardous Weather Outlook is for the Allegheny Front counties in western Maryland, eastern West Virginia, and Highland County Virginia. .DAY ONE...Today and Tonight Isolated severe thunderstorms with damaging wind gusts are possible this afternoon into early evening. .DAYS TWO THROUGH SEVEN...Tuesday through Sunday Isolated severe thunderstorms with damaging wind gusts are possible Wednesday and Saturday. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Sterling radar (KLWX), 67 km away, was scanning. The volume nearest the first event began at 19:07 UTC.
7 thunderstorm wind. Local standard time, as filed.
A tree blew down onto wires blocking the roadway in the 17000 block of MD-63 Spielman Road.
A tree blew down across the roadway near the intersection of Pocock Road and Ebenezer Road.
A tree blew down near the intersection of Oakwood Road and US-222 Rock Springs Road.
A tree blew down near the intersection of Russell Road and Frist Road. A tree blew down onto wires near the intersection of Colora Road and Firetower Road.
A tree blew down near the intersection of Laurel Bush Road and Burgh Westra Way.
A tree blew down near the intersection of MD-462 Paradise Road and Lee Road. A tree blew down blocking the roadway near the intersection of MD-462 Paradise Road and Old Robinhood Road.
A tree blew down near the intersection of Oakington Road and Old Post Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Maryland in 2021Every state in 2021This day in weather historyWarnings in Maryland, July 2021
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 2026-09-24. Each event’s entry at NCEI: 961530, 961531, 961532, 961533, 961537, 961539, 961540.