An upper level trough moved southeastward from the Great Lakes and into the Mid-Atlantic states during the day of August 15th. At the surface, a boundary also moved southeastward from Ohio and into the region.
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.
An upper level trough moved southeastward from the Great Lakes and into the Mid-Atlantic states during the day of August 15th. At the surface, a boundary also moved southeastward from Ohio and into the region. With building instability, scattered showers and thunderstorms developed across the higher elevations in the mid afternoon hours, and then moved eastward during the late afternoon and evening. With relatively strong westerly to west-northwesterly flow aloft, deep layer shear increased and that, combined with the instability, led to some thunderstorms becoming strong to 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 Aug 14, 8:37 PM EST, 5 hours 53 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 937 PM EDT Wed Aug 14 2019 .SYNOPSIS... A stationary front will gradually dissipate over the region by late Friday. An upper level ridge will then bring hot and humid weather to the region this weekend into early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... Latest analysis depicts a nearly stationary frontal boundary draped across the region. Subsidence behind the system which affected the region yesterday, combined with plentiful dry air aloft, has mostly kept convection capped this afternoon and evening, but a few pop-ups may still form, especially as the air aloft moistens and instability tries to increase a little despite the loss of insolation. That having been said, overall trend should be downward for convection through tonight, at least until near sunrise. Weak flow and high low level moisture will again promote low clouds and patchy fog, though as many locations stayed dry the bulk of this afternoon, it will probably be more low clouds versus fog. Lows upper 60s to low 70s. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... While convectively, Wednesday proved to be rather quiet, at least compared to Tuesday, Thursday is not likely to be so benign. The stationary front will remain in the area through the day while a shortwave trough approaches from the west. PW's will climb ahead of the shortwave, approaching 2 inches by afternoon, and instability will build as soon as the sun rises, with CAPE potentially reaching 2000 J/kg by afternoon. However, high moisture and warm temps aloft should make this more of a tall, skinny type of CAPE, one more likely to produce heavy rainers versus severe weather. Storm motion may also not be very fast given low level easterly flow and upper level westerly flow. Bottom line is that showers and thunderstorms are more likely on Thursday than they were today, and the risk of heavy rain (versus severe weather) looks elevated. Some locations got decent rain on Tuesday and a bit more today, but overall, it remains relatively dry, so flash flood guidance has not come down too much. That said, would not be surprised if some flooding did occur. Will let overnight shift re-evaluate, though at this time do not expect any flash flood watches given the likely isolated nature of the threat. A few flash flood warnings may be necessary on Thursday, however. Otherwise, Thursday will be a bit cooler with greater cloud cover and plenty of humidity, with highs mostly in the 80s. Shortwave pulls east Thursday night, allowing convection to subside after sunset. Patchy fog and low clouds will be possible once again, with lows similar to tonight. The front starts to wash out after that, and heights start to build as an upper level ridge to our south starts to flex its muscles on Friday. Thus, have POPs generally below 15 percent all day Friday and Friday night, though an isolated shower or t-storm can't be completely ruled out. With more sunshine and building warmth aloft, highs should be similar to today's, with high 80s and low 90s common. Lows Friday night will be a bit warmer, with low 70s more common. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Weak high pressure will remain over our region through Monday with a weak upper level ridge situated to our north. This setup will help keep warm and humid conditions over our region through Monday. The Warm and humid air will create an environment favorable for continued chances for isolated to scattered thunderstorms and showers forming in our region. Daytime temperatures will trend upwards this weekend with temperatures hovering in the 80s on Saturday and up into the low 90s by Sunday. High pressure will shift off the coast leading to a light southerly flow forming which will advect further moisture into our region. Daytime temperatures Monday into Tuesday will be slightly lower in the mid 80s but the dewpoints will remain elevated in the low 70s. This environment will be favorable for pop up showers and thunderstorms to form due to decent CAPE values above 1500 J/KG. Shear overall is forecast to remain minimal which should limit the development of long lived storms. We will need to continue to monitor how the environment will develop especially if we are able to get some good forcing through our region. && .AVIATION /01Z THURSDAY THROUGH MONDAY/... Low clouds and mist will restrict cigs and vsby later tonight into early Thursday, and likely again later Thursday night into early Friday. Otherwise, main concern will be spotty convection. Terminals should stay dry for rest of tonight, but showers and t-storms likely start developing before noon on Thursday, with highest coverage during the afternoon hours. Storms should die out mostly by midnight. Friday should generally be storm-free, by comparison. High pressure will remain over the terminals this weekend. This should limit the amount of cloud cover over our region and lead to VFR conditions. && .MARINE... Weak gradient with weakening stationary front nearby should prevent widespread SCA gusts, so no headlines are anticipated. However, showers and storms could produce gusty winds on Thursday, mainly in the afternoon, so special marine warnings cannot be ruled out. Storms should be much harder to come by on Friday. High pressure over the waters this weekend will limit the formation of strong winds. SubSCA conditions expected at this time. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && SYNOPSIS...RCM NEAR TERM...RCM SHORT TERM...RCM LONG TERM...JMG AVIATION...RCM/JMG MARINE...RCM/JMG
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 259 AM EDT Thu Aug 15 2019 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-151000- 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- 259 AM EDT Thu Aug 15 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...Tonight No hazardous weather is expected at this time. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053- 055-501>506-151000- 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- 259 AM EDT Thu Aug 15 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...Tonight An isolated storm may be severe near the Blue Ridge Mountains into the Virginia Piedmont overnight. Locally damaging winds are the primary threat. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The Sterling radar (KLWX), 88 km away, was scanning. The volume nearest the first event began at 07:27 UTC.
19 thunderstorm wind, 4 hail. Local standard time, as filed.
A tree was blown down at the intersection of VA-629 and VA-699.
A tree was blown down near the 8300 block of North James Madison Highway.
Both lanes of US-50 were shut down at Four Chimneys Lane due to downed power lines and trees from strong winds.
A tree was blown down blocking the driveway to Briar Patch Bed and Breakfast.
A tree was blown down onto US-15 near Braddock Road.
A 57-knot (66 mph) wind gust was measured at Washington Dulles International Airport.
A tree was blown down on VA-28 Sully Road near Willard Road. Several other trees were also blown down in the immediate area.
A tree was blown down in the 6600 block of Briar Croft Road.
Multiple trees were reported down in the area of Turkey Knob Road and Wissler Road. Damage to barns was also reported along Old Valley Road near Daniel Gray Drive.
Reports were received of multiple barns damaged along Old Valley Pike near Red Banks Road.
Quarter sized hail (1 inch in diameter) was reported at a convenience store in Mount Jackson.
A few trees were blown down near Luray.
Golf ball sized hail (1.75 in diameter) was reported near Grottoes.
Quarter-sized hail (1 in diameter) was reported northeast of Verona.
Trees were blown down in Comertown and Fleeburg.
Half dollar sized hail (1.25 in diameter) was reported north of Hermitage.
A tree was blown down on West Hoover Road.
A tree was blown down on Carpenter Mill Road near Tom Johnson Road.
A tree was blown down on Beahm Town Road.
Trees were blown down onto a house in 100 block of Scott Street. Another tree was also blown down in the 400 block of East Main Street.
Trees were blown down onto a house in the 18000 block of Constitution Highway. Trees were also blown down on May Lane along VA-20 near Orange. Additionally, about 30 trees were blown down across central Orange County.
A tree was blown down onto wires in the 1800 block of Saint John Road.
Large (5 to 6 inch in diameter) tree limbs were blown down in the 6000 block of EDS Road.
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, August 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: 850069, 850070, 850072, 850073, 850074, 850093, 850075, 850076, 850077, 850079, 850094, 850080, 850096, 850097, 850081, 850098, 850083, 850084, 850085, 850087, 850089, 850091, 850092.