Damaging Winds in Virginia, May 23, 2019

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1028 AM EDT Thu May 23 2019

.SYNOPSIS...
High pressure will remain offshore through this afternoon and a
cold front will move into the area tonight. This front will
linger nearby through Saturday, likely dissipated by Sunday
before another cold front sinks into the area from the north.
This boundary will stall out across the Mid Atlantic into the
early portion of next week. As a result, unsettled conditions
can be expected during this period.

&&

.NEAR TERM /THROUGH TONIGHT/...
High pressure will remain offshore today and a southerly flow
will continue to usher in warmer and more humid conditions. Max
temps will top off in the mid to upper 80s across most locations
with a few locations possibly approaching 90 degrees. The
increased heat and humidity will lead to an unstable atmosphere.
Latest modified KIAD sounding shows around 1-2KJ/KG of MLCAPE
developing this afternoon, with some locations possibility
reaching over 2KJ/KG. A convective system is also tracking
through the Ohio Valley into western Pennsylvania this morning.

This system will track through our area this afternoon into this
evening. Latest thinking is that this system will weaken as it
approaches late this morning, but re-development is possible
across our area this afternoon into early this evening due to
the increasing instability. Strong deep layer shear combined
with the instability suggests that severe thunderstorms are
possible this afternoon into this evening. Deep layer shear will
most likely be around 40-50 knots. Current thinking is that the
best chance for strong to severe storms will be near and east of
a pressure trough that should set up near the Blue Ridge and
Catcoctin Mountains this afternoon. However, given the strong
shear profiles and relatively favorable mid-level lapse rates,
there is a threat for severe storms across the entire area. Do
think that overall coverage of the severe storms will be
isolated to scattered since the lifting mechanism is relatively
weak. Locally damaging wind gusts and large hail are the primary
threats, but an isolated tornado cannot be ruled out due to the
strong shear profiles.

In preparation for today's potential severe threat, ensure you
and your family have multiple ways to receive warnings and have
a plan and place to take shelter if needed.

Another round of showers and thunderstorms are possible later
this evening ahead of the cold front. Instability will be more
limited, but the shear profiles will be quite strong. Therefore,
an isolated severe storm cannot be ruled out with this activity,
especially across northern Maryland/northern VA/eastern WV.
Activity will diminish overnight as instability continues to
decrease and the cold front drops farther south.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/...
The front will settle over central and southern Virginia on
Friday, as drier air filters over the area on a northwesterly
breeze. Highs will still reach the upper 70s to low 80s, but
with dewpoints dropping back into the 50s, a pleasant Friday is
in store. Transient high pressure will cross the area Friday
night, moving offshore on Saturday. This will bring a return
flow to the area once again, with temperatures and dewpoints
increasing once again. The frontal boundary will start to lift
northward as a warm front, kinking across the Appalachians. As
such, afternoon showers and isolated thunderstorms will be
possible on Saturday over the higher terrain. Dry conditions in
store Saturday night with temperatures remaining mild well into
the 60s.

&&

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
Bermuda high will dominate the weather Sunday, resulting in a flow
of very warm to borderline hot and humid air northward across our
region. However, a cold front sliding southeastward will set the
stage for some late day convection. Latest GFS and EC both drop the
front southward across the region for Memorial Day, with more
clouds, cooler air and perhaps a shower or two expected. Wave of low
pressure then rides northward across the Great Lakes on Tuesday,
pulling the cold front back north as a warm front. Bermuda high
influence should return after the warm front passes Tuesday, and
continue through Wednesday at least, resulting in more very warm and
humid weather. A stray shower or t-storm couldn't be ruled out
either day, with highest risk in the mountains, but the odds would
be low.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
Predominate VFR conditions at the terminals through midday,
with the threat for showers and storms this afternoon and
evening. Some storms may be severe, with damaging wind gusts
being the primary threat, however large hail and an isolated
tornado is also possible. Convection will wane overnight with
VFR conditions returning overnight.

Drier conditions and northerly breezes are expected Friday and
Friday night, with VFR conditions winning out. Afternoon
showers/storms on Saturday could impact MRB with an episode of
sub VFR VIS/CIGs, but all other terminals will remain in VFR
under a light southerly flow.

Thunderstorms may impact the terminals Sunday afternoon/evening as a
cold front slides southward. Low clouds could impact the terminals
Monday behind the front.

&&

.MARINE...
SCA conditions will exist over the waters through this evening
as southerly flow increases and mixing is favorable ahead of an
approaching cold front. Showers and thunderstorms will cross the
waters this afternoon and evening, with some severe storms
bringing the potential for damaging wind gusts. Timeframe for
this activity will be between 4-8pm, but another round of
thunderstorms are possible late this evening, especially across
the northern Bay. Activity will wind down overnight. A cold
front will cross the waters overnight, settling to the south on
Friday. SCA conditions are expected on Friday under a gusty
northwest flow. Winds turn light Friday night as high pressure
traverses the region.

Southerly winds increase on Saturday afternoon, bringing the
potential for SCA conditions once again. Special Marine
Warnings may be needed Sunday as thunderstorms develop in the
vicinity. Small Craft Advisories may be needed Sunday and Monday
as a cold front crosses the region.

&&

.TIDES/COASTAL FLOODING...
The southerly flow has caused elevated anomalies, and that will
continue through this evening. Minor flooding is possible, but
confidence is too low for an advisory at this point, since the
flow will turn just west of south. The flow will turn toward
the west overnight and northwest Friday, causing anomalies to
decrease.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until midnight EDT tonight for ANZ531>534-
     537-539>541-543.
     Small Craft Advisory from 7 AM to 8 PM EDT Friday for
     ANZ530>543.
     Small Craft Advisory until midnight EDT tonight for ANZ530-535-
     536-538-542.

&&

SYNOPSIS...BKF
NEAR TERM...BJL/BKF
SHORT TERM...BKF
LONG TERM...RCM
AVIATION...BJL/BKF/RCM
MARINE...BJL/BKF/RCM
TIDES/COASTAL FLOODING...BJL

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
104 PM EDT Thu May 23 2019

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-241000-
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-
104 PM EDT Thu May 23 2019

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...This Afternoon and Tonight

A Severe Thunderstorm Watch is in effect until 8 pm this evening.
Isolated to scattered severe thunderstorms are possible this
afternoon and evening. Locally damaging winds and large hail are
the primary threats, but an isolated tornado cannot be ruled out
as well.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.

MDZ003>006-501>507-VAZ025>031-036>040-050-051-501>508-WVZ050>053-
055-501>506-241000-
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-
104 PM EDT Thu May 23 2019

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...This Afternoon and Tonight

A Severe Thunderstorm Watch is in effect until 8 PM this evening
for portions of northern and central Virginia, central Maryland,
and the eastern Panhandle of West Virginia. Isolated to scattered
severe thunderstorms are possible this afternoon and evening.
Locally damaging winds and large hail are the primary threats, but
an isolated tornado cannot be ruled out as well.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed this afternoon and evening.