In the afternoon hours of September 11th, a weak upper level trough approached the region from the Ohio Valley. This coupled with abundant surface heating led to the development of showers and thunderstorms by the afternoon and evening hours.
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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.
In the afternoon hours of September 11th, a weak upper level trough approached the region from the Ohio Valley. This coupled with abundant surface heating led to the development of showers and thunderstorms by the afternoon and evening hours. |With ample instability and modest shear, some thunderstorms became locally severe.
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 Sep 11, 9:30 AM EST, 4 hours 20 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1030 AM EDT Wed Sep 11 2019 .SYNOPSIS... A weak warm front will cross the region this morning as high pressure builds over the southeastern United States. A backdoor cold front will drop southward out of Pennsylvania Thursday, stall across central Virginia Friday, then return north as a warm front Saturday. Another front moving in from the northwest will stall in the area Sunday before it also lifts north by Monday. && .NEAR TERM /THROUGH TONIGHT/... Visible satellite imagery shows the low cloud deck from earlier this morning quickly eroding, with the last of the low clouds now confined to far northeastern Maryland. Expect all areas to clear out over the next hour, with ample sunshine through the remainder of the morning and into the early afternoon hours. 12z sounding shows an 850 hPa temperature of 19C, with 850 temps expected to approach 20C later this afternoon. Given ample sunshine and warm temperatures aloft, temperatures today are expected to max out in the low to mid 90s. When coupled with dewpoints in the upper 60s to near 70, heat index values will reach near 100 along the I-95 corridor. By later this afternoon, a weak shortwave will approach from the Ohio Valley. Ascent in advance of the feature, along with strong surface heating will encourage the development of thunderstorms later this afternoon. Storms are expected to fire along a lee trough located in the general vicinity of the Blue Ridge around 4 PM, then progress southeastward during the early evening hours. Currently it appears as though the highest chances for storms along the urban corridor will be between 5 and 7 PM. Although a thunderstorm can't be ruled out anywhere in the CWA, CAM guidance has focused in on areas along and east of the Blue Ridge. This is reflected in the POP grids, but chances for isolated storms are still maintained over the entire area. Model soundings show around 2000 J/kg of MLCAPE by peak heating, with around 20 knots of flow through much of the troposphere. Given the modest values of shear, multicell clusters are expected to be the predominant storm mode, with a storm motion off to the ESE at 15-20 knots. This morning's modified sounding as well as model soundings show a well-mixed sub-cloud layer with 1300-1400 J/kg of DCAPE, suggesting that strong downdrafts will be the primary threat with any storms that form. As a result, the entire area is under a marginal threat for severe thunderstorms from SPC, with damaging winds as the driving factor. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Scattered convection is possible again Thursday afternoon and evening as backdoor front approaches. Actual cdfnt is not expected to cross the area until late Thu night, but outflow from convection to the north could trigger new convection in hot unstable air mass. Backdoor front will get hung up against the Appalachians Fri night. Anticipate overcast skies Fri with showers possible. Expect temperatures on Fri to be as much as 15F degs cooler than Thursday. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Front stalled to the south is progged by most guidance to move back northward during the day Saturday, allowing temperatures to warm back up again with some sun returning. However, with the boundary in the vicinity and increased instability, a risk of showers and t-storms will also be present. Another front moving in from the northwest is then expected to stall in the region Saturday night into Sunday, before it too lifts northward by Monday. Timing on its stall and return northward is a bit more uncertain, making Sunday's forecast for temps in particular a bit tricky. Monday is more certain to be warm. Risk of precip may linger Sunday with the new front stalled in the area, but should decline Monday. By Tuesday, guidance varies significantly, with some models holding the ridge from the south in place, while others drop another front into the region. && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... Scattered t-storms expected today mainly between 19Z-23Z and have added VCTS to every TAF. Scattered convection possible again Thu. MVFR cigs likely Fri on cool side of bdry. Low clouds are possible early Saturday and again Saturday night/early Sunday as fronts stall in the vicinity, but uncertainty is high. Otherwise, main concern will be for spotty showers and t-storms, mainly during the afternoon and evening hours. && .MARINE... T-storms this afternoon may pose a risk of strong wind gusts and SMWs may be required. Likely SCA conditions Thu night and Fri due to strong onshore flow. Winds most likely stay sub-SCA, though repeated frontal passages will result in brief intervals when SCA gusts could occur on the waters both Saturday and Sunday. Uncertainty in this potential is very high. && .TIDES/COASTAL FLOODING... Water levels remain a half to three quarters of a foot above astronomical normals. At this time, no inundation is anticipated today or on Thursday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && SYNOPSIS...RCM NEAR TERM...KJP SHORT TERM...LFR LONG TERM...RCM AVIATION...RCM/LFR MARINE...RCM/LFR TIDES/COASTAL FLOODING...HTS
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 504 AM EDT Wed Sep 11 2019 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-120915- 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-Southern Baltimore-Prince Georges- Anne Arundel-Charles-St. Marys-Calvert-Southeast Harford- Prince William/Manassas/Manassas Park-Fairfax- Arlington/Falls Church/Alexandria-Stafford-Spotsylvania- King George- 504 AM EDT Wed Sep 11 2019 This Hazardous Weather Outlook is for the Maryland portion of the Chesapeake Bay, Tidal Potomac River, and adjacent counties in central Maryland and northern Virginia as well as the District of Columbia. .DAY ONE...Today and Tonight Isolated severe thunderstorms with damaging wind gusts and large hail are possible this afternoon and evening. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon. MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053- 055-501>506-120915- Washington-Frederick MD-Carroll-Northern Baltimore- Extreme Western Allegany-Central and Eastern Allegany- Northwest Montgomery-Central and Southeast Montgomery- Northwest Howard-Central and Southeast Howard-Northwest Harford- Augusta-Rockingham-Shenandoah-Frederick VA-Page-Warren-Clarke- Nelson-Albemarle-Greene-Madison-Rappahannock-Orange-Culpeper- Northern Fauquier-Southern Fauquier-Western Highland- Eastern Highland-Western Loudoun-Eastern Loudoun- Northern Virginia Blue Ridge-Central Virginia Blue Ridge- Hampshire-Morgan-Berkeley-Jefferson-Hardy-Western Grant- Eastern Grant-Western Mineral-Eastern Mineral-Western Pendleton- Eastern Pendleton- 504 AM EDT Wed Sep 11 2019 This Hazardous Weather Outlook is for eastern West Virginia, northern and central Virginia, and central and western Maryland with the exception of Garrett County. .DAY ONE...Today and Tonight Isolated severe thunderstorms with damaging wind gusts and large hail are possible this afternoon and evening. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation may be needed this afternoon.
The national radar mosaic for the moment the first event began.
29 thunderstorm wind. Local standard time, as filed.
A tree was blown down on Saint Luke Road near Wisman Road.
A tree was blown down on Stony Hill Road near Northwestern Turnpike.
A tree was blown down in the 12500 block of Scotts Mill Road.
Multiple trees were blown down on Jordan Springs Road in the Stephens area. Multiple trees were also reported down on Stephenson Road.
Five to six inch in diameter tree limbs were blown down on the Lord Fairfax Community College campus.
Multiple trees were blown down in the Mount Solon area. Large tree branches were blown down on Emmanuel Church Road. A tree was also blown down near the 500 block of Towers Road. Another tree was blown down near Staunton and Weyers Cave.
A tree was blown down on Manor Road in the area of Ridgewood Lane.
A tree was blown down in the 2200 block of Leeds Manor Road.
A tree was blown down on Stonewall Jackson Road near Rocky Lane.
A tree was blown down in the 10200 block of Pleasant Vale Road.
Multiple trees were blown down on Zachary Taylor Highway in the Flint Hill area. A tree was also reported down on Hittles Mill Road.
Multiple trees were blown down on parts of Crest Hill Road.
A tree was blown down in the 5700 block of Wilson Road.
A tree was blown down on Citation Drive near Bears Den Road.
Multiple trees were blown down in the area of Courthouse Road and Elk Run Road.
Multiple trees were blown down on Laurel Mills Road.
A tree was blown down in the 6700 block of Beach Road. Another tree was blown down on Opal Road near Sir Topas Drive.
A tree was blown down on Slate Mills Road near Sperryville Pike. Another tree was reported down in the 12200 block of Yeawood Drive.
A tree was blown down in the 8800 block of Old Dumfries Road.
A tree was blown down on Crozet Avenue near Ballard Drive. A tree was also blown down in the 2000 block of Lakeside Drive.
A tree was blown down on Tennant Church Road near Mill Hill Road.
Multiple trees were blown down in the area of West Hoover Road and Ridgeview Road.
Trees were blown down in the area of the 6100 block of Advance Mills Road.
A tree was blown down in the 4900 block of Seminole Trail. Trees and power lines were also blown down in the 5000 block of Watts Passage Road.
A tree was reported down on Dudley Mountain Road near Poplar Drive.
A tree was blown down in the 2600 block of Frays Mill Road.
A tree was blown down on Perkins Hollow Lane near Hickory Creek Road.
A tree was blown down on Telegraph Road near Den Rich Road.
A tree was blown down in the 14200 block of James Madison Highway.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2019Every state in 2019This day in weather historyWarnings in Virginia, September 2019
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: 855094, 855095, 855112, 855096, 855125, 855097, 855098, 855099, 855100, 855101, 855102, 855103, 855104, 855105, 855106, 855107, 855109, 855110, 855111, 855113, 855114, 855115, 855116, 855117, 855119, 855121, 855122, 855123, 855124.