Flash Flood Warning 21, NWS Baltimore/Washington

806 
WGUS71 KLWX 182037
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
437 PM EDT Sat Jul 18 2026

MDC021-182215-
/O.CON.KLWX.FF.W.0021.000000T0000Z-260718T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Frederick MD-
437 PM EDT Sat Jul 18 2026

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM EDT THIS 
EVENING FOR SOUTHERN FREDERICK COUNTY IN NORTH CENTRAL MARYLAND...

At 437 PM EDT, Doppler radar indicated thunderstorms producing heavy 
rain across the warned area. Between 1 and 3 inches of rain have 
fallen. The expected rainfall rate is 0.25 inches in 1 hour. 
Additional rainfall amounts up to 0.5 inches are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Flash flooding caused by thunderstorms.

SOURCE...Radar.

IMPACT...Flash flooding of small creeks and streams, urban areas,
         highways, streets and underpasses as well as other poor
         drainage and low-lying areas.

Some locations that will experience flash flooding include...
  Frederick...                       Harry Grove Stadium...
Ballenger Creek...                 Braddock Heights...
New Market...                      Linganore-Bartonsville...
Clover Hill...                     Discovery-Spring Garden...
Adamstown...                       Jefferson...
Buckeystown...                     Monrovia...
Park Mills...                      Ijamsville...
Clifton...                         Doubs...
Mount Pleasant...                  Middletown In Frederick Md...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

&&

LAT...LON 3935 7725 3933 7727 3930 7731 3927 7743
      3933 7754 3935 7755 3942 7756 3945 7744
      3946 7734 3943 7728 3937 7723

FLASH FLOOD...RADAR INDICATED
EXPECTED RAINFALL RATE...0.25 INCHES IN 1 HOUR

$$

KLW

932 
WGUS71 KLWX 182046
FFSLWX

Flash Flood Statement
National Weather Service Baltimore MD/Washington DC
446 PM EDT Sat Jul 18 2026

MDC021-182056-
/O.CAN.KLWX.FF.W.0021.000000T0000Z-260718T2215Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Frederick MD-
446 PM EDT Sat Jul 18 2026

...FLASH FLOOD WARNING IS CANCELLED FOR SOUTHERN FREDERICK COUNTY IN 
NORTH CENTRAL MARYLAND...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

A Flood Watch remains in effect until 800 PM EDT for portions of DC, 
Maryland, and northern Virginia.

&&

LAT...LON 3935 7725 3933 7727 3930 7731 3927 7743
      3933 7754 3935 7755 3942 7756 3945 7744
      3946 7734 3943 7728 3937 7723

$$

KLW

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
256 PM EDT Sat Jul 18 2026

.WHAT HAS CHANGED...
Thunderstorms have intensified east of the Blue Ridge Mountains
as of 2:55 PM this afternoon. Strong to severe storms are likely
for the DC and Baltimore Metropolitan areas through the Bay over
the next few hours through 7 PM. The best chance for severe
storms will be between 4 PM and 6 PM for the DC and Baltimore
Metro areas, and through 7 PM farther east.

&&

.KEY MESSAGES...
- 1) Hot and humid conditions with a risk of severe
  thunderstorms today.

- 2) Thunderstorm chances may linger across southern portions of
  the area as the front stalls to the south Sunday and Monday.

- 3) A strong cold front and trough of low pressure may bring
  severe weather Tuesday and/or Wednesday.

&&

.DISCUSSION...
KEY MESSAGE 1...Hot and humid conditions with a risk of severe
thunderstorms today.

15Z mesoanalysis indicates a corridor of (even higher) theta-e
air at 925-850 hpa approaching the Appalachian crest. A surface
trough roughly along I-81 is evident in surface analysis. As the
low-level moist plume approaches from the west and interacts
with the surface trough, anticipate steady to rapid expansion of
thunderstorms in the vicinity of the Blue Ridge by 1-2pm.

Upstream convective development is already widespread over SW
PA, OH and WV. See no reason given the environment that this
won't continue to expand as it presses eastward given the very
humid and unstable airmass in place.

Regarding the flood threat, individual storm cells will likely
be moving given flow aloft, but the flow is oriented parallel to
the lifting mechanism (nearby warm front). Back-building cells
or clusters (possibly transient HP supercells) as well as
multiple rounds are possible. Areas with lower FFG and in
complex terrain around western MD would be of particular
concern, and a watch is in effect there until 2am. To the east,
there may be a hint downsloping/rain shadow, with most model
QPFs showing a relative min between the Alleghenies and I-81.
Farther to the east, the metro areas are typically more
vulnerable to begin with. Here, multiple rounds of storms with
some (but not as strong as further west) signal of back-
building, as well as a conglomeration of bay/river breezes,
outflow, and the nearby warm front, could still result in heavy
rainfall. This is another area to be monitored later today, with
a Flood Watch now in effect 2-8pm.

With surface winds turning southerly and winds aloft turning
southwesterly, there should be an improvement in smoke and air
quality from south to north through the midday hours.

Skies may not become completely sunny, but it won't take much to
warm up. It will also be very humid with dew points in the lower to
mid 70s. Heat index values will likely range from 100-105 east of
the Blue Ridge and mid to upper 90s in the lower elevations to the
west. A Heat Advisory has been issued for the I-95 corridor from
Baltimore southward. This area is expected to have the most heating
before storms arrive, and higher dew points will likely remain
pooled east of a developing lee trough in this area.

With 30+ kt of deep layer shear, the hot and humid airmass will
result in substantial instability and a favorable environment for
severe thunderstorm development. A primary focus for storm
initiation and/or intensification will be the lee trough east of the
Blue Ridge. Most CAMs have storms developing in this area by early
to mid afternoon. Storms will likely also develop well upstream in
the Great Lakes closer to the surface front. What happens in between
these features is a bit more uncertain, though additional
thunderstorms are certainly possible given the strong upper trough
and deepening surface low to the north. Some areas could see
multiple rounds. The primary hazard will be damaging winds, with
some considerable swaths of damage possible in any sustained
supercells or linear segments. Some isolated large hail is possible,
but modest mid level lapse rates will be a limiting factor. A
tornado is also possible, with the greatest chances in northeast
Maryland where low level flow will be more favorable. Frequent
lightning and heavy rainfall are likely with any storm. Precipitable
water values surge to greater than 2 inches. The flash flood threat
appears to be isolated and limited to any areas with localized
training or repeating storms, as overall storm motions should be
progressive. The QPF signal is highest in northeast MD.

A secondary concentration of thunderstorms will develop closer to
the cold front near the Great Lakes. Most guidance shows this
activity rapidly weakening as it approaches the area during the late
evening, with some stronger storms potentially reaching the
Allegheny Front. The REFS does show a bit more persistence to these
storms however. Either way, there will be a drying trend the second
half of the night.

KEY MESSAGE 2...Thunderstorm chances may linger across southern
portions of the area as the front stalls to the south Sunday and
Monday.

The cold front will push south through the area Sunday. By the time
convection initiates, it may largely be south of the forecast area.
However, there is enough uncertainty in the frontal position that
the I-64 corridor in central VA could see some thunderstorms on
Sunday. The greatest risk for severe thunderstorms remains south of
the area.

High pressure briefly building to the north will bring cooler
temperatures Sunday and Monday. The front will stall temporarily but
begin to lift back north Monday into Monday night. Depending how
quickly this occurs, some showers and thunderstorms could move back
into the area.

KEY MESSAGE 3...A strong cold front and trough of low pressure
may bring severe weather Tuesday and/or Wednesday.

A strong upper trough and cold front will cross the region Tuesday
into Wednesday. There still remains uncertainty in timing and
placement of upper trough and front, along with coverage of
convection each day. It looks as if there will be secondary cold
front to follow the first front sometime midday Wednesday into the
afternoon. As we get closer in time each day, we will have a better
feel for this convective period of time in the middle of the week.

SPC outlooks denote roughly at 15% risk Tuesday into Wednesday from
west to east, with various ML/AI guidance a tick or two higher than
that. Damaging winds will likely be the primary threat with storms,
although other hazards cannot be ruled out pending the placement of
the trough and ingredients at play.

Behind this system will be lower humidity and cooler than normal
temperatures for the second half of next week with high pressure
returning to the region.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...
Smoke continues to reduce visibilities. These conditions should
improve from south to north through midday as southerly winds
pick up, which could potentially gust to 20 kt this afternoon.

Additional thunderstorms are likely this afternoon, especially for
the metro terminals. Coverage is a bit more uncertain for CHO and
MRB. Timing is also a bit uncertain, and it's not out of the
question there could be multiple rounds. Thunderstorms may be strong
to severe with strong winds, hail, frequent lightning, and very
heavy rain. A possibly weakening line of storms may approach during
the late evening as it drops in from the northwest, but it may
largely fall apart first. Winds will shift back to the N and NW
behind the cold front heading into Sunday. CHO may remain close
enough to the front to see more thunderstorms Sunday afternoon.

Prevailing VFR conditions are expected Monday, though some guidance
has showers and thunderstorms working back northward with a warm
front by afternoon or Monday night.

Possible sub-VFR conditions on Tuesday into Wednesday. Showers and
thunderstorms could push through multiple times. We will monitor the
set up as we get past this weekend. Winds southeast to south 5 to 10
knots Tuesday. Winds south to southwest 10 to 15 knots
Wednesday.

&&

.MARINE...
Southerly winds strengthen by this afternoon in the wake of the
warm front. Advisories have been issued from 11 AM to 11 PM for
all waters, and lingering for the mid bay through the night.
Strong to severe storms are possible this afternoon and evening
as well, which may prompt Special Marine Warnings.

Leftover storms on Sunday would probably be limited to areas around
southern MD, but trends suggest they will form farther to the south.
Otherwise winds become northerly in the front's wake, and could
result in marginal advisory conditions.

Expect sub-SCA level conditions Sunday night into Monday as high
pressure builds to the north. Southerly channeling may increase
winds by Monday night.

SCA conditions due to southerly channeling could occur Tuesday into
Wednesday as a storm system and two possible cold fronts push across
the region. Winds southeast 10 to 15 knots Tuesday. Winds south 10
to 20 knots gusts higher Wednesday.

&&

.TIDES/COASTAL FLOODING...
Increasing southerly flow today and again on Tuesday could lead
to water levels approaching minor flood stage, especially at
Annapolis. However, current trends suggest levels should fall
short of flood stage today/tonight.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flood Watch until 8 PM EDT this evening for DCZ001.
     Heat Advisory until 7 PM EDT this evening for DCZ001.
MD...Flood Watch until 8 PM EDT this evening for MDZ004>006-008-011-
     013-014-503>508.
     Small Craft Advisory until 11 PM EDT this evening for MDZ008.
     Heat Advisory until 7 PM EDT this evening for MDZ011-013-014-
     016>018.
     Flood Watch until 2 AM EDT Sunday for MDZ501-502-509-510.
VA...Flood Watch until 8 PM EDT this evening for VAZ053-054-505-506.
     Heat Advisory until 7 PM EDT this evening for VAZ053>057-527.
WV...Flood Watch until 2 AM EDT Sunday for WVZ503-504.
     Air Quality Alert until midnight EDT tonight for WVZ050-055-
     501>504.
MARINE...Flood Watch until 8 PM EDT this evening for ANZ530.
     Small Craft Advisory until 11 PM EDT this evening for
     ANZ530>533-535-536-538>542.
     Small Craft Advisory until 6 AM EDT Sunday for ANZ534-537-543.

&&

DISCUSSION...ADS/KLW/DHOF
AVIATION...ADS/KLW/DHOF
MARINE...ADS/KLW/DHOF

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
220 PM EDT Sat Jul 18 2026

ANZ530>543-DCZ001-MDZ008-011-013-014-016>018-504-506-508-
VAZ053>057-527-191830-
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-Fairfax-Arlington/Falls Church/Alexandria-
Stafford-Spotsylvania-King George-
Central and Southeast Prince William/Manassas/Manassas Park-
220 PM EDT Sat Jul 18 2026

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...This Afternoon and Tonight

A Heat Advisory is in effect until 7 PM for much of the area from
Baltimore southward.

A Tornado Watch is in effect for central and northeast Maryland
from Prince Georges County to Cecil Counties until 9 PM. A Severe
Thunderstorm Watch is in effect for the rest of the area during
this time. Severe thunderstorms will be capable of producing
damaging winds with wind gusts around 70 mph, large hail, and
perhaps a tornado.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Severe thunderstorms with damaging wind gusts are possible
Tuesday and Wednesday of next week.

.SPOTTER INFORMATION STATEMENT...

Spotters have been activated.

MDZ003>006-503-505-507-VAZ025>031-036>040-050-051-501-502-505>508-
526-WVZ050>053-055-191830-
Washington-Frederick-Carroll-Northern Baltimore-
Northwest Montgomery-Northwest Howard-Northwest Harford-Augusta-
Rockingham-Shenandoah-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-
Northwest Prince William-Hampshire-Morgan-Berkeley-Jefferson-
Hardy-
220 PM EDT Sat Jul 18 2026

This Hazardous Weather Outlook is for portions of eastern West
Virginia, northern and central Virginia, and central and western
Maryland.

.DAY ONE...This Afternoon and Tonight

A Tornado Watch is in effect for central Maryland until 9 PM. A
Severe Thunderstorm Watch is in effect for the rest of the area
until 9 PM this evening. Severe thunderstorms will be capable of
producing damaging winds with wind gusts around 70 mph, large
hail, and perhaps a tornado.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Severe thunderstorms with damaging wind gusts are possible
Tuesday and Wednesday of next week.

.SPOTTER INFORMATION STATEMENT...

Spotters have been activated.

MDZ501-502-509-510-VAZ503-504-WVZ501>506-191830-
Extreme Western Allegany-Central and Eastern Allegany-
Western Garrett-Eastern Garrett-Western Highland-Eastern Highland-
Western Grant-Eastern Grant-Western Mineral-Eastern Mineral-
Western Pendleton-Eastern Pendleton-
220 PM EDT Sat Jul 18 2026

This Hazardous Weather Outlook is for the Allegheny Front
counties in western Maryland, eastern West Virginia, and Highland
County Virginia.

.DAY ONE...This Afternoon and Tonight

A Severe Thunderstorm Watch is in effect until 9 PM. Multiple
rounds of showers and thunderstorms are expected through this
evening. Some thunderstorms may become severe, with damaging wind
gusts being the primary threat. In addition, very heavy rain
could result in isolated flash flooding. A Flood Watch is in
effect for western MD and Mineral County WV through tonight.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Severe thunderstorms with damaging wind gusts are possible Tuesday
and Wednesday of next week.

.SPOTTER INFORMATION STATEMENT...

Spotters have been activated.

Special Weather Statement
National Weather Service Baltimore MD/Washington DC
1255 PM EDT Sat Jul 18 2026

MDZ509-510-181745-
Eastern Garrett-Western Garrett-
1255 PM EDT Sat Jul 18 2026

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL GARRETT COUNTY...

At 1254 PM EDT, a strong thunderstorms were located over Preston
and Garrett Counties, moving east around 30 mph.

HAZARD...Wind gust 30 to 40 mph and lightning along with heavy
         downpours that may lead to ponding of water on roadways.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Mountain Lake Park, Oakland, Bittinger, Deer Park, Merrill, Hutton,
Jennings, Deep Creek Lake State Park, Swallow Falls State Park,
McHenry, Big Run State Park, New Germany, Piney Grove, and McComas
Beach.

This includes Interstate 68 in Maryland between mile markers 23 and
26.

&&

LAT...LON 3971 7902 3960 7900 3948 7907 3947 7910
      3946 7910 3946 7911 3945 7910 3944 7912
      3943 7911 3941 7948 3956 7948
TIME...MOT...LOC 1654Z 259DEG 26KT 3953 7939

BJL

Preliminary Local Storm Report
National Weather Service Baltimore MD/Washington DC
152 PM EDT Sat Jul 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0148 PM     Tstm Wnd Dmg     3 SSW Madison           38.35N  78.28W
07/18/2026                   Madison            VA   911 Call Center

            A tree was down along Route 29 and Gibbs Road.

&&

Event Number LWX2607364

BJL

Preliminary Local Storm Report
National Weather Service Baltimore MD/Washington DC
202 PM EDT Sat Jul 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0145 PM     Tstm Wnd Dmg     Winchester              39.17N  78.17W
07/18/2026                   Frederick          VA   Emergency Mngr

            Several trees down in Winchester.

&&

Event Number LWX2607365

DH

Special Weather Statement
National Weather Service Baltimore MD/Washington DC
239 PM EDT Sat Jul 18 2026

MDZ509-510-181945-
Eastern Garrett-Western Garrett-
239 PM EDT Sat Jul 18 2026

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT GARRETT COUNTY...

At 238 PM EDT, radar indicated strong thunderstorms were located
along a line extending from Ursina to 7 miles west of Friendsville to
6 miles north of Newburg. Movement was southeast at 25 mph.

HAZARD...Wind gust 30 to 40 mph and lightning along with heavy
         downpours that may lead to ponding of water on roadways.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects.

Locations impacted include...
Mountain Lake Park, Oakland, Bayard, Bittinger, Grantsville, Loch
Lynn Heights, Friendsville, Deer Park, Accident, Redhouse, Hutton,
Gorman, Jennings, Crellin, Deep Creek Lake State Park, Swallow Falls
State Park, McHenry, Big Run State Park, Piney Grove, and McComas
Beach.

This includes Interstate 68 in Maryland between mile markers 1 and
30.

&&

LAT...LON 3972 7893 3948 7907 3947 7910 3946 7909
      3943 7911 3941 7914 3942 7916 3939 7916
      3939 7919 3936 7922 3936 7925 3930 7929
      3930 7933 3922 7943 3920 7949 3972 7948
TIME...MOT...LOC 1838Z 296DEG 23KT 3981 7935 3964 7955 3949 7987

BJL

Preliminary Local Storm Report
National Weather Service Baltimore MD/Washington DC
247 PM EDT Sat Jul 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0211 PM     Tstm Wnd Dmg     1 WSW Jefferson         39.36N  77.56W
07/18/2026                   Frederick          MD   Dept of Highways

            Trees down along MD 340 and 180.

&&

Event Number LWX2607366

BJL

Preliminary Local Storm Report
National Weather Service Baltimore MD/Washington DC
259 PM EDT Sat Jul 18 2026

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0236 PM     Tstm Wnd Dmg     Charlottesville         38.04N  78.49W
07/18/2026                   Albemarle          VA   911 Call Center

            Trees down in the Charlottesville area.

&&

Event Number LWX2607367

BJL