A negatively tilted trough and associated surface low tracked into Ohio. Warm, humid air streamed northward into the area in southerly flow well in advance of the low.
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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.
A negatively tilted trough and associated surface low tracked into Ohio. Warm, humid air streamed northward into the area in southerly flow well in advance of the low. A band of pre-frontal storms moved across VA, transporting some of the high winds from aloft down to the surface.
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 Jan 11, 9:19 PM EST, 2 hours 34 minutes earlier.
Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 919 PM EST Sat Jan 11 2020 .SYNOPSIS... Low pressure will move northeast from the Ohio Valley into the Great Lakes tonight. The cold front associated with the low will pass through our area overnight into early Sunday morning. High pressure will return for later Sunday, but the cold front will stall, then return north as a warm front for the early and middle portion of next week. Unsettled conditions are possible during this time. && .NEAR TERM /UNTIL 7 AM SUNDAY MORNING/... Negatively tilted shortwave is lifting across the Ohio Valley this evening with associated surface low over Ohio. CAMs have been handling the northern edge of convection fairly poorly, so evolution is of low confidence for the remainder of the night. Persistent bowing segment approaching from the southwest may try to weaken as it reaches our area as it outraces the best instability. Recent HRRR runs generally paint this trend in the ongoing convection. However, it's still possible this isn't the "main show" with additional development ahead of the approaching surface trough late tonight (scenarios outlined below are still generally valid). Low level jet will transport moisture/CAPE ahead of this boundary, making the resurgence possible. Forecast 0-1km CAPE, 0-500m shear, and (relative lack of) surface based CIN near the convection suggest strong to severe winds could make it to the surface if organized convection can develop AND orient in a SW>NE direction (perpendicular to low level shear vector). The best overlap of these parameters are generally along our southern border in the Fredericksburg vicinity. While a brief QLCS tornado can't be ruled out due to low level shear, this seems like a low probability, and CAMs show little in terms of updraft helicity tracks. With shallow/weak instability, it's possible severe weather could occur without lightning, so people should make sure they have a way to be alerted to warnings given the overnight timing. Previous discussion: Winds remain gusty out of the south, though they have decreased a bit with sunset. That may not be the case as the night progresses, as the LLJ will gradually strengthen through the remainder overnight hours as the system approaches from the west, ultimately reaching near 70 knots at 850 hPa by around 06z. With a near moist-neutral profile in place, the highest winds aren't expected to mix down to the lowlands outside of any enhanced areas of convection. However, higher winds winds are expected in background southerly flow over the ridgetops as the LLJ strengthens. Winds Advisories have been issued for the Blue Ridge and higher elevations near the Allegheny Front to account for these higher winds. Moving into the overnight hours, the main shortwave will lift from the lower MS Valley toward the OH Valley by 06z, eventually tracking across the eastern Great Lakes/Upstate NY by 12z. As this occurs, the zone of mid-upper level forcing for ascent and associated area of precipitation are expected to translate toward the north and east. What remains of the squall line(s) currently stretching from the OH Valley southward to the Gulf of Mexico is expected to reach western portions of our forecast area (Allegheny Front) around midnight, then track eastward across the Mid-Atlantic through the overnight hours. There are mixed signals in the CAM guidance with respect to what will happen with this line as it moves eastward into our area. There are a few potential scenarios that could occur: 1. The leading edge of the squall line and trailing area of stratiform rain holds together across the Appalachians and tracks across our area intact. In this scenario, we'd have a low end threat for some stronger wind gusts along the leading line. 2. The leading edge of the squall line weakens or outright falls apart as it encounters the higher terrain/tracks away from the strongest forcing for ascent. In this scenario, the region of stratiform rain would still work across the area, but the threat for damaging wind gusts would be minimized. 3. The leading edge of the squall line weakens or falls apart as it crosses the mountains, but additional redevelopment of storms occurs to the east of the Appalachians. This scenario was depicted by some of the HRRR runs throughout the day. A few of these runs had additional redevelopment occurring behind or within the stratiform rain area, but ahead of the surface cold front, while others showed the redevelopment taking place immediately along the surface cold front. In this scenario, the best chance for strong wind gusts would be within the areas of secondary redevelopment. Continued warm advection in southerly flow will keep conditions warm overnight, with temperatures holding in the 60s and dewpoints climbing well into the 60s ahead of the line. The combination of mid 60s temps and dewpoints will result in limited instability at the surface. The 12z HREF ensemble mean shows 100-300 J/kg of surface based instability streaming northward to the east of the Blue Ridge immediately in advance of the line, with very limited to no surface based instability to the west of the Blue Ridge. High values of shear will be present across the entire area, with 0-1 km shear values climbing to near 60 kts as the core of the LLJ slides overhead. With the strong LLJ in place just off the surface, current thinking is that the primary threat will be isolated damaging wind gusts in association with stronger convective elements that are able to bring those higher winds from aloft down to the surface. Damaging wind gusts would be most likely with any line segment whose motion is southwest to northeast, orthogonal to the LLJ. However, the moist neutral profile will temper this potential somewhat. Can't completely rule out a brief spin up either given limited instability and extreme values of SRH of 500-700 m^2/s^2. The best synoptic scale forcing lifting to the north of our area (as well as the time of day and the time of year) will be a major limiting factor. Precipitable water values will surge to well in excess of 1.5 inches ahead of the line (which could be outside the observed range of January PW values in the IAD sounding climatology; max is 1.64"). With this high PW air in place, heavier downpours can't be ruled out in any stronger convective elements. However, we aren't expecting any flash flood or flood issues given the relatively short duration of the precipitation and fast storm motion. && .SHORT TERM /7 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... Any precipitation should clear the area by around daybreak, with the surface cold front clearing the Chesapeake Bay by early to mid morning. Winds may remain elevated for a few hours behind the front in westerly flow, but should subside rather quickly by the afternoon hours. Skies will be mostly sunny with temperatures holding in the 50s to the west/60s to the east as cold advection aloft offsets solar heating at the surface. Given the lack of appreciable cold air advection immediately behind the front and downsloping W/NW flow, temperatures may eclipse 70 F once again. The cold front from tonight's system will stall to our south, and could potentially return north as a warm front by late Monday into Monday Night in response to a disturbance tracking to our north. Model guidance differs on the northward progression of the front, but there could be a few showers across far southern portions of the forecast area Monday Night. Temperatures will continue to run well above normal for January, with high in the 50s to near 60 on Monday. && .LONG TERM /TUESDAY THROUGH SATURDAY/... A stationary front across southern Virginia will meander north and south Tuesday through Wednesday. This front will bring some light rain northward into our region Tuesday before the rain becomes more showery Tuesday night and Wednesday. Temperatures will be above normal for mid-January during both days and at night. By Wednesday night, the western end of the stationary front will get a little push northward as it links up with low pressure over the lower Great Lakes. The low pressure will move eastward toward southern New England Wednesday night and Thursday. A developing cold front on the southwest flank of the low will drag across our region Thursday and Thursday night. Limited moisture ahead of the cold front appears keep chances of rain showers minimal for now. The pattern will begin to flip by the end of the week as strong, cold high pressure fills in behind the cold front bringing colder-than-normal air southeastward into our region. Dry conditions will ensue during the day Friday. As for late Friday through early Saturday, the cold dome of high pressure will build southward along the eastern slopes of the Appalachian Mountains. There is a chance that most of us could see a mix of rain and snow with this cold air anchoring into the region and some overrunning moisture pushing in from the southwest. The 12Z ECMWF/GFS/CMC all agree on this, but given the time range and inherent ensemble spread this far out, it is too early to tell in terms of rain or snow amounts, but at the very least it looks unsettled during this time. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Gusty south winds to 30 kt continue this evening with ceilings lowering into the MVFR range. Am thinking IFR potential is low, except at CHO, and as any heavier rain showers arrive later tonight. A few light showers are possible this evening, but shouldn't reduce visibility appreciably. Low level wind shear is likely ongoing as well with 44 kt measured at 2000 ft. A line of showers and potentially even a thunderstorm or two will move across the area later tonight. The most likely time for this activity to move across the metro terminals will be between 07Z and 10z, although the evolution could be messy and is uncertain. CHO could see convection much earlier. Briefly higher winds will be possible with any stronger convective elements that move over the terminals. Vsbys could briefly drop to to IFR or LIFR in any heavier downpours, as well. The surface cold front associated with the system should clear the terminals by daybreak. Conditions will return to VFR behind the cold front, and winds will become westerly. Winds could be gusty for a few hours early tomorrow morning, but will subside through the course of the day. VFR conditions are then expected on Monday. Drops to sub-VFR can't be ruled out Monday Night with a stationary boundary in place to our south, especially at CHO. Sub-VFR conditions possible at CHO, DCA and IAD Tuesday with rain on the north side of a stationary front wavering over south- central Virginia. Elsewhere, VFR conditions are most likely. VFR conditions are expected at all terminals Tuesday night with a few showers around, with VFR likely again Wednesday and Wednesday night. && .MARINE... A cold front will approach tonight and pass to the east Sunday morning. Ahead of this front, southerly winds are gusting 20 to 30 knots. An isolated gust to near 35 kts is possible. Small Craft Advisories have been issued to cover this. A line of showers and a few thunderstorms is expected to move across the waters very late tonight into very early Sunday morning. As of now, it appears as though the most likely time window for the line to impact the waters will be between 4 AM and 7 AM. As this line of storms passes through, Special Marine Warnings may be needed. Locally reduced visibility in fog is also possible as very warm, moist air moves over the colder waters. After the cold front moves past our waters, a few hours of SCA gusts will be possible in westerly flow, especially across northern parts of the Bay. Winds are expected to subside through the late morning hours and into the afternoon, with conditions dropping below SCA levels by mid to late afternoon. Sub-SCA level winds are then expected on Monday as the aforementioned front stalls to the south. No marine hazards are expected Tuesday through Wednesday. Small Craft Advisories may be needed Wednesday night in strengthening southerly flow ahead of low pressure approaching from the west, but questions remain relating to mixing given warm air over relatively cooler water. && .TIDES/COASTAL FLOODING... Strong southerly flow will continue ahead of a cold front through Sunday morning. The flow is just west of due south, though, resulting in a slight offshore component, especially near the mouth of the Chesapeake Bay. As a result, virtually all available model guidance keeps tides below minor thresholds through tomorrow, and current trends support this. Some caution stages could be reached. Winds become westerly behind said cold front Sunday, resulting in decreasing water levels. ETSS/ESTOFS/Snap-Ex show tides dropping to a foot below MLLW by Monday morning, but am a pinch skeptical of this outcome given a lack of particularly strong northwest flow. && .CLIMATE... Well above normal temperatures are expected this weekend. Daytime highs are forecast to be 20-30 degrees above normal today and Sunday. Temperatures tonight are expected to be 30 to 35 degrees above normal. Record daily warm temperatures are possible. As of now, it appears that the record highs are a bit higher than our forecasts, but it could be close. For reference, the record daily warm temperatures (highs/lows) for January 11th and 12th are listed below: Record Daily High Temperatures for January 11th: Washington DC area: 75 F (set in 1975) Baltimore MD area: 73 F (set in 1975) Sterling/Dulles VA area: 71 F (set in 1975) Record Daily Warm Low Temperatures for January 11th: Washington DC area: 56 F (set in 1975) Baltimore MD area: 48 F (set in 1975) Sterling/Dulles VA area: 45 F (set in 1975) Record Daily High Temperatures for January 12th: Washington DC area: 76 F (set in 1890) Baltimore MD area: 70 F (set in 2017 and 1890) Sterling/Dulles VA area: 70 F (set in 2018 and 2017) Record Daily Warm Low Temperatures for January 12th: Washington DC area: 57 F (set in 2018) Baltimore MD area: 53 F (set in 2018) Sterling/Dulles VA area: 58 F (set in 2018) && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Wind Advisory until 5 AM EST Sunday for MDZ501. VA...Wind Advisory until 5 AM EST Sunday for VAZ503-504-507-508. WV...Wind Advisory until 5 AM EST Sunday for WVZ501-503-505-506. MARINE...Small Craft Advisory until noon EST Sunday for ANZ530>543. && SYNOPSIS...DHOF NEAR TERM...ADS/KJP SHORT TERM...KJP LONG TERM...KLW AVIATION...ADS/KLW/KJP MARINE...ADS/KLW/KJP TIDES/COASTAL FLOODING...ADS/DHOF CLIMATE...DHOF
Hazardous Weather Outlook National Weather Service Baltimore MD/Washington DC 714 PM EST Sat Jan 11 2020 ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-130015- 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- 714 PM EST Sat Jan 11 2020 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 A line of showers and isolated thunderstorms will be capable of producing locally damaging wind gusts overnight. The best chance for damaging winds will be between 2 AM and 6 AM. .DAYS TWO THROUGH SEVEN...Sunday through Friday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. Please report any wind gusts in excess of 45 MPH or wind damage per standard operating procedures. MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053- 055-501>506-130015- 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- 714 PM EST Sat Jan 11 2020 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 A Wind Advisory is in effect until 5 AM for the central and northern Virginia Blue Ridge and Highland County in Virginia, Pendleton, western Grant and western Mineral Counties in West Virginia and extreme western Allegany County in Maryland. A line of showers and isolated thunderstorms will be capable of producing locally damaging wind gusts overnight. The best chance damaging winds will be between midnight and 5 AM. .DAYS TWO THROUGH SEVEN...Sunday through Friday No hazardous weather is expected at this time. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. Please report any wind gusts in excess of 45 MPH or wind damage per standard operating procedures.
The Sterling radar (KLWX), 104 km away, was scanning. The volume nearest the first event began at 04:51 UTC.
3 thunderstorm wind. Local standard time, as filed.
A tree was down on Madison Run Road near Gordonsville.
A tree was down on Indiantown Road in Locust Grove.
Tree reported down on Eleys Ford Road near Jennings Road.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Virginia in 2020Every state in 2020This day in weather historyWarnings in Virginia, January 2020
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: 874151, 874152, 874153.