Hail and Damaging Winds in Maryland, August 12, 2017

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
252 PM EDT Sat Aug 12 2017

.SYNOPSIS...A cold front will move through the area this evening
and become stationary across the Carolinas early in the week.
Weak high pressure builds over the area Sunday and holds through
mid week.

&&

.NEAR TERM /THROUGH TONIGHT/...Cdfnt is currently moving through
wrn PA and the OH river as seen on moisture discontinuity on 24-hr
microphysics GOES-16 RGB. Air mass over the area ahead of front
has destabilized after morning low clouds and fog with MLCAPE
around 1000 J/kg. 0-6 km shear is respectable with around 45 kt,
but appears limiting factor for severe storms is strongest forcing
will remain north of the Mason-Dixon line. Nevertheless, expect
nrms-widespread showers and sct thunderstorms as the front comes
through later this evening with best chance of showers between
5PM-9PM. Activity will end from west to east after 8PM but
linger through at least midnight in the southeast over srn St.
Marys county. Definitely not expecting a repeat of last night.

Some low clouds are possible over upslope areas overnight,
otherwise lots of high clouds overnight.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...Weak high pressure
will build over the area Sun and hold through the middle of the
week. Low clouds and a few showers will be possible Sun night
into Mon as sfc flow turns onshore but it will remain too stable
for t-storms.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...

Upper shortwave/surface reflection should depart to the east of the
area Tuesday, leading to a drying trend through the middle of next
week as high pressure builds. Decent model agreement through mid
week, which includes a stark warming trend by Thursday. Models then
diverge on timing/orientation of the next upper level wave and
surface front that would in theory bring the next chance of
organized precip.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...A brief t-storm is
possible through 01Z tonight. Cdfnt then crosses the area with
winds shifting and clouds scattering out.

Mainly VFR Tue-Wed. Patchy fog possible Tue night in areas
that receive rain if dry advection isn't strong enough prior to
nightfall. NW flow AOB 10 kts.

&&

.MARINE...Gusty showers and t-storms possible over the waters
this evening. SMWs may be required. Cdfnt crosses the waters
late this evening.

Generally light winds expected mid-week as high pressure
moves over the waters.

&&

.TIDES/COASTAL FLOODING...Minor coastal flooding possible at
Straits Point early this evening.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Coastal Flood Advisory until 8 PM EDT this evening for MDZ017.
VA...None.
WV...None.
MARINE...None.

&&

SYNOPSIS...LFR
NEAR TERM...LFR
SHORT TERM...LFR
LONG TERM...DFH
AVIATION...LFR/DFH
MARINE...LFR/DFH
TIDES/COASTAL FLOODING...LFR

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
913 AM EDT Sat Aug 12 2017

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-131000-
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-
913 AM EDT Sat Aug 12 2017

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...Today and Tonight

Gusty showers are possible across the waters this afternoon and
evening.

.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.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-131000-
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-
913 AM EDT Sat Aug 12 2017

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...Today and Tonight

Isolated severe thunderstorms with damaging wind gusts and large
hail are possible particularly across northern Maryland and the
eastern panhandle of West Virginia.

.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.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1209 PM EDT SAT AUG 12 2017

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

0714 PM     TSTM WND DMG     3 SE MANASSAS           38.71N  77.44W
08/11/2017                   PRINCE WILLIAM     VA   PUBLIC

            MULTIPLE TREES KNOCKED OVER AND UPROOTED WITH A FEW
            SNAPPED IN HALF ALONG BLANDSFORD DR

&&

EVENT NUMBER LWX1702746

KLW

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC
1228 PM EDT SAT AUG 12 2017

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

0608 PM     TORNADO          1 W BROAD RUN           38.82N  77.73W
08/11/2017                   FAUQUIER           VA   NWS STORM SURVEY

            EF0 WITH 75 MPH MAX WINDS AND MAX PATH WIDTH OF 100
            YARDS. NUMEROUS TREES UPROOTED AND LARGE BRANCHES
            SNAPPED. SOME FELL ON POWER LINES AND HOUSES.

&&

EVENT NUMBER LWX1702747

DH