WW 509 SEVERE TSTM DC DE MD NC VA WV CW 211845Z - 220200Z
URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 509
NWS Storm Prediction Center Norman OK
245 PM EDT Tue Jul 21 2026
The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
District Of Columbia
Delaware
Maryland
Far Northwest North Carolina
Virginia
The Eastern West Virginia Panhandle
Coastal Waters
* Effective this Tuesday afternoon and evening from 245 PM until
1000 PM EDT.
* Primary threats include...
Scattered damaging wind gusts to 70 mph likely
Isolated large hail events to 1.5 inches in diameter possible
A tornado or two possible
SUMMARY...Multiple rounds of strong to severe thunderstorms are
expected across the region today and tonight, beginning with the
ongoing storms across central Virginia. Environmental conditions
support robust updrafts, with all severe hazards possible, including
damaging gusts and isolated hail. A low-probability tornado risk
exists with any afternoon development as well. Another round of
storms is possible along a cold front later tonight, with damaging
gusts as the primary risk. A low-probability, line-embedded tornado
risk exists with these more linear storms as well.
The severe thunderstorm watch area is approximately along and 105
statute miles east and west of a line from 30 miles north northeast
of Baltimore MD to 10 miles west of South Hill VA. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).
PRECAUTIONARY/PREPAREDNESS ACTIONS...
REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.
&&
OTHER WATCH INFORMATION...CONTINUE...WW 506...WW 507...WW 508...
AVIATION...A few severe thunderstorms with hail surface and aloft to
1.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
26030.
...Mosier
WW 0510 Status Updates
STATUS REPORT ON WW 510
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 20 E MKL TO
30 NE MKL TO 10 S BNA.
WW 510 WILL BE ALLOWED TO EXPIRE AT 220500Z.
..MEAD..07/22/26
ATTN...WFO...JKL...MRX...MEG...OHX...RLX...
STATUS REPORT FOR WS 510
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
TNC039-055-077-081-099-101-117-119-135-181-187-220500-
TN
. TENNESSEE COUNTIES INCLUDED ARE
DECATUR GILES HENDERSON
HICKMAN LAWRENCE LEWIS
MARSHALL MAURY PERRY
WAYNE WILLIAMSON
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
WW 0509 Status Updates
STATUS REPORT ON WW 509
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 35 S WAL TO
40 W RIC TO 30 SW SHD TO 20 W HGR.
FOR ADDITIONAL INFORMATION SEE MESOSCALE DISCUSSION 1702
..WEINMAN..07/22/26
ATTN...WFO...LWX...PHI...AKQ...RNK...
STATUS REPORT FOR WS 509
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
DEC001-005-220140-
DE
. DELAWARE COUNTIES INCLUDED ARE
KENT SUSSEX
DCC001-220140-
DC
. DISTRICT OF COLUMBIA COUNTIES INCLUDED ARE
DISTRICT OF COLUMBIA
MDC003-005-009-011-013-015-017-019-021-025-027-029-031-033-035-
037-039-041-043-045-047-510-220140-
MD
. MARYLAND COUNTIES INCLUDED ARE
ANNE ARUNDEL BALTIMORE CALVERT
WW 0508 Status Updates
STATUS REPORT ON WW 508
SEVERE WEATHER THREAT CONTINUES RIGHT OF A LINE FROM 25 SSW PAH
TO 35 N LOZ.
..MEAD..07/22/26
ATTN...WFO...PAH...LMK...JKL...
STATUS REPORT FOR WS 508
SEVERE WEATHER THREAT CONTINUES FOR THE FOLLOWING AREAS
KYC001-003-009-025-035-047-051-053-057-075-083-105-109-125-129-
141-153-169-171-189-199-207-213-219-221-227-231-220140-
KY
. KENTUCKY COUNTIES INCLUDED ARE
ADAIR ALLEN BARREN
BREATHITT CALLOWAY CHRISTIAN
CLAY CLINTON CUMBERLAND
FULTON GRAVES HICKMAN
JACKSON LAUREL LEE
LOGAN MAGOFFIN METCALFE
MONROE OWSLEY PULASKI
RUSSELL SIMPSON TODD
TRIGG WARREN WAYNE
THE WATCH STATUS MESSAGE IS FOR GUIDANCE PURPOSES ONLY. PLEASE
REFER TO WATCH COUNTY NOTIFICATION STATEMENTS FOR OFFICIAL
INFORMATION ON COUNTIES...INDEPENDENT CITIES AND MARINE ZONES
CLEARED FROM SEVERE THUNDERSTORM AND TORNADO WATCHES.
MD 1707 CONCERNING SEVERE THUNDERSTORM WATCH 509... FOR PARTS OF CENTRAL AND EASTERN VIRGINIA
Mesoscale Discussion 1707
NWS Storm Prediction Center Norman OK
1101 PM CDT Tue Jul 21 2026
Areas affected...parts of central and eastern Virginia
Concerning...Severe Thunderstorm Watch 509...
Valid 220401Z - 220530Z
The severe weather threat for Severe Thunderstorm Watch 509
continues.
SUMMARY...A localized damaging wind and tornado threat may persist
into the overnight hours. As such, the watch has been extended until
05Z.
DISCUSSION...Satellite and radar data suggest multiple waves of
forcing for ascent moving through the region, which are supporting
more isolated storms now emerging from the Blue Ridge and a larger
complex of storms approaching the Tidewater Region. A warm and very
moist air mass resides within the inflow to these storms with latest
objective analysis indicating MLCAPE as high as 1000-2000 J/kg with
minimal convective inhibition. Moreover, the current KAKQ VWP is
sampling quite strong low-level shear with 0-1 km SRH of 400-450
m2/s2. The low-level shear decreases with westward extent, with the
KFCX indicating a respectable 0-1 km SRH of around 200 m2/s2.
It remains unclear whether the current storms are truly rooted
within the moist, unstable boundary layer, or slightly elevated. On
the condition storms are surface based, the potential exists for a
couple tornadoes along with locally damaging winds. As such, the
watch has been extended until 05z.
..Mead.. 07/22/2026
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...AKQ...LWX...RNK...
LAT...LON 37667956 37977947 38137718 38077626 37677594 37437633
37377816 37527946 37667956
MOST PROBABLE PEAK TORNADO INTENSITY...85-110 MPH
MOST PROBABLE PEAK WIND GUST...55-70 MPH
SPC 0100Z Day 1 Outlook
Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0754 PM CDT Tue Jul 21 2026
Valid 220100Z - 221200Z
...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FROM THE LOWER
OHIO VALLEY INTO THE TENNESSEE VALLEY AND PARTS OF THE
MID-ATLANTIC...
...SUMMARY...
Scattered severe storms remains possible this evening within the
Tennessee Valley into the Mid-Atlantic. Damaging winds will be the
primary risk, though a couple of tornadoes could occur with the most
organized storms.
...Synopsis...
A notable shortwave tough will continue moving through the
Mid-Atlantic/Northeast into tonight. Convective overturning from
earlier this afternoon has stabilized much of Pennsylvania/New York
into New England. Forcing for ascent from the shortwave trough and
the surface cold front will allow for isolated activity to persist
tonight. Wind damage remains possible. An MCV is evident in northern
Virginia. This will continue to promote storm development into parts
of the Mid-Atlantic. Earlier activity has reduced buoyancy, but flow
fields will increase as the trough continues to approach. Wind
damage will continue to be the main threat, though a couple of
tornadoes could occur with the strongest storms. MLCAPE of 3000+
J/kg is still present within the Tennessee Valley vicinity. A
cluster of storms north of Nashville will pose the greatest risk for
damaging winds as it tracks southward into the instability axis.
Other strong to severe storms may impact parts of the eastern Great
Basin. Severe wind gusts are the concern in that region.
..Wendt.. 07/22/2026
SPC Day 1 Fire Weather Outlook
Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1201 AM CDT Wed Jul 22 2026
Valid 221200Z - 231200Z
...Synopsis...
Upper-level troughing will remain in place across the eastern U.S.
as a southward progressing cold front promotes widespread chances of
rainfall along the Eastern Seaboard today. Meanwhile, tropical
remnants will continue to translate northward along the western
periphery of a large-scale ridge across the western CONUS. As high
pressure shifts towards the Four Corners, additional monsoonal
moisture will advect into the Pacific Northwest.
A mix of wet/dry thunderstorms are expected across the IsoDryT area,
with overall coverage likely exceeding 50% across central/southern
Oregon--perhaps approaching 80% in central Oregon. PWAT values are
expected to approach 0.9-1.3" amid southerly flow induced training
of storms, indicating wetting rain is likely across portions of the
area. However, given a drought-stressed fuelscape and numerous
ongoing wildfires, lightning-induced ignitions will remain a concern
on the periphery of heavier precipitation. The lightning threat will
then shift northward into southwestern WA through the evening and
overnight hours. Forecast soundings depict dry sub-cloud layers up
to 700 mb, ample instability (MUCAPE greater than 500 J/kg), and
15-25 kt storm motions. This meteorological setup greatly increases
fire weather concerns as several days of dry and windy conditions
are expected to follow, potentially impacting nascent wildfires born
from thunderstorm activity.
..Elizalde-Garcia.. 07/22/2026
...Please see www.spc.noaa.gov/fire for graphic product...
SPC Day 2 Fire Weather Outlook
Day 2 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
1203 AM CDT Wed Jul 22 2026
Valid 231200Z - 241200Z
...Synopsis...
Upper-level troughing will continue across the eastern U.S. on Day
2/Thursday as surface high pressure builds in across the Ohio Valley
behind a southward progressing cold front. A long-lived upper ridge
across the Pacific Northwest will finally begin to flatten and break
down owing to an approaching eastern Pacific upper trough.
...Pacific Northwest and Northern Rockies...
As upper-level flow transitions from broadly southerly to
southwesterly, monsoonal moisture will be shunted northeastward as a
dry airmass returns to the Inland Northwest. Daytime
destabilization, ample mid-level moisture, and fast storm motions
over the Columbia Basin into the Northern Rockies will promote
isolated wet/dry thunderstorms. In addition, preceding days of hot
and dry conditions have further exacerbated the fuelscape, leading
to widespread 90-95th percentile ERCs. As upper level flow
strengthens and impinges upon the Northwest, tightening pressure
gradients along the Cascades will promote very gusty winds amid a
very dry boundary layer. Elevated highlights have been introduced
where RH values should decline to less than 20% as winds increase to
15-20 mph (localized gusts up to 35 mph in terrain-favored areas).
Greater concern for new ignitions and impacts to ongoing fires exist
where the Elevated and Isolated Dry Thunderstorm highlights overlap.
...Carolinas...
Residual dry and breezy conditions will continue across the
Carolinas ahead of a slow approaching cold front. At peak heating,
RH values will decline to 30-40 percent as southwesterly winds
increase to 15 mph amid 80-90th percentile ERCs. Scattered to
widespread thunderstorms and heavy rainfall are expected across the
region as the front pushes through, bringing relief to the fuelscape
and alleviating broader fire concerns.
..Elizalde-Garcia.. 07/22/2026
...Please see www.spc.noaa.gov/fire for graphic product...
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