A weak trough spawned several severe thunderstorms over the far eastern West Virginia panhandle, extreme northern Virginia, and north-central Maryland.
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.
A weak trough spawned several severe thunderstorms over the far eastern West Virginia panhandle, extreme northern Virginia, and north-central Maryland.
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 27, 1:46 PM EST, 54 minutes earlier.
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
246 PM EDT Thu Jul 27 2023
.SYNOPSIS...
A Bermuda high will remain in place offshore through Saturday.
A surface trough will remain overhead through Saturday before a
cold front passes through the area Saturday night into Sunday.
High pressure will likely return early next week while an
upper-level trough builds overhead.
&&
.NEAR TERM /THROUGH TONIGHT/...
The mid-level clouds have dissipated for the most part, and this
has allowed for hot and humid conditions. The Heat Advisory for
near/east of Interstate 81 to the Bay remains in effect for heat
indices around 100 to 105 degrees.
The heat and humidity has led to plenty of instability. Latest
mesoanalysis shows around 1 to 3 KJ/KG of MLCAPE, but there is
inhibition as of early this afternoon. Current feeling is that a
surface trough axis over southwest PA will merge into a weak
trough over north-central MD into northern VA as the upper-level
trough axis to our north moves eastward. This added lift should
be enough for some storms to develop late this afternoon. If
storms do develop, then more storms will likely develop due to
the boundaries produced by the convection. Shear is marginal,
but higher CAPE and DCAPE suggest that damaging winds are a
threat, along with the possibility of large hail. There is the
possibility that coverage of severe storms can be numerous
around northern VA into the DC and Baltimore Metro areas for
reasons mentioned above.
Convection will gradually wane later this evening into the
overnight, but the warm and humid conditions will persist.
&&
.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
Bermuda high pressure will continue to cause hot and humid
conditions Friday. In fact, it should turn out even hotter due
to more sunshine (less mid-level clouds than what occurred
today). For that reason, an Excessive Heat Warning is in effect
for the I-95 corridor to the Bay, with Heat Advisories for most
other locations to the west (except the ridges).
The heat and humidity will lead to higher CAPE, and a surface
trough will remain overhead. Therefore, more scattered severe
storms are possible during the afternoon and evening with
damaging winds and large hail being the primary threat. The best
chance for stronger storms will be east of the Blue Ridge
Mountains.
Convection should wane Friday evening, but an upper-level
disturbance may trigger more convection overnight into Saturday
morning. A cold front will drop closer to the area from the
north later Saturday while the flow aloft strengthens. Hot and
humid conditions will likely persist (assuming we can get enough
of a break behind the morning activity), and Heat Advisories
may be needed for heat indices around 100 to 105 degrees.
Additional thunderstorms are possible Saturday afternoon and
evening, and some may be severe due to stronger shear profiles
and moderate to higher CAPE. The front will likely drop into the
region Saturday, and more convection may persist through the
night.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
A frontal passage is expected Saturday night into Sunday morning,
bringing potentially unsettled weather. Uncertainty remains with
this disturbance, especially with cloud debris ahead of the line
serving as a limiting factor. Nonetheless, showers and thunderstorms
will be possible Sunday during the day. Shortly thereafter, high
pressure will build into the Mid-Atlantic, bringing drier conditions
across the area through midweek next week. Highs after Sunday will
begin to trend towards normal or even slightly below normal for late
July/early August.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Thunderstorms are possible through this evening, with the most
likely time for storms between 20z and 01z. Some storms may
produce damaging winds and subVFR conditions.
VFR conditions are most likely later tonight through Friday, but
there may be patchy fog overnight. Also, more thunderstorms are
possible Friday afternoon and evening, especially across the
eastern terminals. There is a better chance for storms Saturday
into Saturday night as a cold front drops toward the area from
the north.
VFR conditions are expected Sunday and Monday with
some isolated instances of sub-VFR conditions Sunday with any
passing showers and thunderstorms across the terminals.
Northwesterly wind gusts on Sunday may be 15-20 knots Sunday
afternoon before subsiding by Monday.
&&
.MARINE...
A Small Craft Advisory is in effect through this evening for the
waters, and into Friday morning for the open waters of the
middle Bay and lower Tidal Potomac River. Thunderstorms may
produce damaging winds through this evening that require Special
Marine Warnings.
Scattered storms are possible Friday afternoon and evening, and
some may produce strong winds. More storms are possible Saturday
into Saturday night with strong winds possible.
Winds may approach SCA criteria Saturday ahead of a cold front.
Small Craft Advisories may be needed Sunday as a result of
increasing northwesterly winds. Additionally, SMW's may be needed
Sunday afternoon and evening should a strong thunderstorm cross the
waters. High pressure builds in for the beginning of the workweek
and into midweek next week, leading to weakened winds.
&&
.TIDES/COASTAL FLOODING...
A southerly component to the wind may cause water levels to
reach action stages over the next couple days, but confidence
for minor flooding is low.
&&
.CLIMATE...
Potential for daily temperature records Thu (7/27) through Sat (7/29)
Washington/Reagan National:
7/27 high 100 (1940)
7/27 low 81 (2016)
7/28 high 100 (1997)
7/28 low 80 (1949)
7/29 high 104 (2011)
7/29 low 80 (2011)
Washington Dulles Airport:
7/27 high 98 (1993)
7/27 low 75 (2016)
7/28 high 99 (1993)
7/28 low 75 (1963)
7/29 high 103 (2011)
7/29 low 74 (2002)
Baltimore/Washington Arpt:
7/27 high 101 (1940)
7/27 low 82 (1930)
7/28 high 103 (1941)
7/28 low 82 (1949)
7/29 high 101 (2011)
7/29 low 82 (1949)
Martinsburg Airport:
7/27 high 105 (1930)
7/27 low 76 (1892)
7/28 high 101 (1952)
7/28 low 75 (1892)
7/29 high 103 (1941)
7/29 low 77 (1941)
LENGTH OF CLIMATE RECORDS:
Washington/Reagan National: Since 1872 Washington Dulles
Airport: Since 1960 Baltimore/Washington Arpt: Since 1872
Martinsburg Airport: Since 1891
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Heat Advisory until 8 PM EDT this evening for DCZ001.
Excessive Heat Warning from 11 AM to 8 PM EDT Friday for
DCZ001.
MD...Heat Advisory until 8 PM EDT this evening for MDZ003>006-008-
011-013-014-016>018-503>508.
Excessive Heat Warning from 11 AM to 8 PM EDT Friday for
MDZ008-011-013-014-016>018-504-506-508.
Heat Advisory from 11 AM to 8 PM EDT Friday for MDZ003>006-502-
503-505-507.
VA...Heat Advisory until 8 PM EDT this evening for VAZ027>031-039-
040-050-051-053>057-501-502-505-506-526-527.
Excessive Heat Warning from 11 AM to 8 PM EDT Friday for
VAZ053>057-527.
Heat Advisory from 11 AM to 8 PM EDT Friday for VAZ025>031-
036>040-050-051-501-502-505-506-526.
WV...Heat Advisory until 8 PM EDT this evening for WVZ051>053.
Heat Advisory from 11 AM to 8 PM EDT Friday for WVZ050>053-055-
502-504.
MARINE...Small Craft Advisory until 8 PM EDT this evening for
ANZ530>532-535-536-538>542.
Small Craft Advisory until 10 AM EDT Friday for ANZ533-534-537-
543.
&&
SYNOPSIS...BJL
NEAR TERM...BJL
SHORT TERM...BJL
LONG TERM...ADM
AVIATION...BJL/ADM
MARINE...BJL/ADM
TIDES/COASTAL FLOODING...BJL
CLIMATE...LWX<!doctype html>
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</html>The Sterling radar (KLWX), 56 km away, was scanning. The volume nearest the first event began at 19:40 UTC.
1 thunderstorm wind, 1 hail. Local standard time, as filed.
Tree damage was reported near Shepherdstown, including a large tree that blew down on private property along CR-16/1 Gardners Lane.
Quarter size hail was reported near Shenandoah Junction and Shepherdstown.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in West Virginia in 2023Every state in 2023This day in weather historyWarnings in West Virginia, July 2023
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 2026-10-01. Each event’s entry at NCEI: 1107821, 1107822.