Hail and Damaging Winds in Virginia, May 3, 2019

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
253 PM EDT Fri May 3 2019

.SYNOPSIS...

Weak low pressure will push through the region today, resulting
in showers and thunderstorms today, some of which may be severe.
A stationary front will remain over the region through Sunday,
with several areas of low pressure moving along it, resulting in
an unsettled weekend. A stronger area of low pressure will push
through the region Saturday night into Sunday, which will push
the front offshore finally, allowing high pressure to return.
High pressure will remain overhead Monday night before building
to the south Tuesday. A backdoor cold front may impact the area
during the middle and latter portions of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...

A stationary front remains anchored over the northern portions
of the CWA. Diurnally induced convection has initiated in
eastern WV and for western VA, and storms will then move
towards the northeast. These storms are developing in a very
favorable environment south of the stationary front, where
SBCAPE values are in the 1500-2500 J/kg range, and bulk shear is
on the order of 40kts. These are both well within the range to
support organized severe thunderstorms, some of which could
contain damaging winds and some hail. As a result, the Storm
Prediction Center has issued a Severe Thunderstorm Watch from
2-10 PM this evening. Thinking the hail threat is a bit limited,
given unfavorable mid-level lapse rates, but with CAPE over
2000 J/kg in spots, can not be ruled out. Damaging winds appears
to be the primary threat with any storms that form today.
Temperatures for today will reach the low to mid 80s south of
the front, but areas north of the front likely only reach the
low 70s.

Later this evening, a second round of storms will push through
the region later this evening into tonight. Throughout the day,
the probability of a gap between the two rounds has become less
and less in the hi-res guidance, so expecting a pretty
continuous period of showers and storms, especially in the area
outlined in the Severe Thunderstorm Watch. This second round is
associated with a weak shortwave and associated surface low
that will push across the region. Early on, the severe threat
will continue, with the primary threat again being some damaging
winds and small hall. Showers will linger tonight, but should
mostly clear the area by 3-4 AM.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...

Saturday looks to be quieter across the mid-Atlantic, at least
during the morning. Weak high pressure will build across the
region and push the surface low and upper level support to the
east and off the East Coast. Slightly cooler air will filter in
on a brief northwest wind Saturday morning into the afternoon.
By later in the day, surface winds will back around to the
southwest once again ahead of the next low pressure system. The
best chance for any shower activity Saturday will be in the
Potomac Highlands. The next low pressure system should arrive
from the southwest late Saturday into Sunday morning. Expecting
a period of moderate rain in association with this system, with
some rumbles of thunder also possible.

As the low and the bulk of its energy moves to the east-
northeast and offshore Sunday, weak trailing upper level
energy could spawn a couple of gusty showers Sunday afternoon
and be mainly along the Mason-Dixon region. Elsewhere will
encounter a drying northerly to northwest breeze. Weak high
pressure should provide some dry relief Sunday night.
Temperatures will not be as warm as recent days and nights.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...

First half of next week looks tranquil under high pressure in
control both at the sfc and aloft and sfc front well to the
north over Pennsylvania. The front begins to slide south on Thu
with risk of showers and thunderstorms increasing. Expect an
unsettled period the second half of next week with front taking
its time to cross the area. Anticipate daily chances of showers
and thunderstorms during this period.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...

MVFR/IFR conditions expected to continue at BWI/MTN thanks to
stubborn low clouds associated with the stationary front. This
may clear in the next few hours. Otherwise, VFR elsewhere for
now, but thunderstorms are developing in the higher elevations
and are expected to impact the northern terminals, especailly
MRB/BWI/MTN. MRB should see storms this afternoon, with BWI/MTN
getting in on the action this evening. IAD/DCA will be on the
southern fringe of showers and storms this evening, so a little
more uncertainty there.

Tonight, expecting another period of low CIGs, and potentially
low VIS Saturday morning, especially at MRB/BWI/MTN thanks to
the rain this evening. Keeping MVFR in for now roughly in the
08z- 13z time frame. Other terminals should remain VFR.

VFR conditions expected tomorrow, but MVFR, perhaps IFR, will
return Saturday night into Sunday, as rain moves into the
region.

VFR conditions expected Monday through Wednesday.

&&

.MARINE...

No marine hazards are expected through Saturday night. However,
southerly winds will come close to SCA criteria for a period
this afternoon in the Bay. Also, afternoon and evening
thunderstorms are possible and some of them may have gusty winds
with them, so Special Marine Warnings may be needed at some
point this afternoon/evening.

Small Craft Advisories possible Sunday into Sunday evening on
the back side of an exiting low.

Winds appear to remain below SCA through Wednesday under surface
high pressure.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...None.

&&

SYNOPSIS...CJL
NEAR TERM...CJL
SHORT TERM...CJL/KLW
LONG TERM...LFR
AVIATION...LFR/CJL
MARINE...LFR/CJL

Hazardous Weather Outlook
National Weather Service Baltimore MD/Washington DC
233 PM EDT Fri May 3 2019

ANZ530>543-DCZ001-MDZ011-013-014-016>018-508-VAZ052>057-041845-
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-
233 PM EDT Fri May 3 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

Scattered thunderstorms are expected late this afternoon through
this evening. A couple thunderstorms may become severe with the
potential for locally damaging wind gusts, especially across the
Washington and Baltimore Metropolitan areas.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Showers are expected Saturday night into Sunday along with the
possibility of a few thunderstorms. Rain may be heavy at times
which could lead to flooding of small streams and creeks as well
as urban areas. Confidence remains low in regards to how
widespread the flood threat will be.

.SPOTTER INFORMATION STATEMENT...

Limited 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>506-041845-
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-
233 PM EDT Fri May 3 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

Showers are likely with scattered thunderstorms this afternoon
through this evening. Severe Thunderstorm Watch has been issued
until 10 PM for portions of northern VA, eastern WV and western
MD. The primary risk will be damaging winds. Localized flooding of
small streams and creeks as well as urban areas are possible
during this time as well.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Showers are expected late Saturday into Sunday along with the
possibility of a few thunderstorms. Rain may be heavy at times
which could lead to flooding of small streams and creeks as well
as urban areas. Confidence remains low in regards to how
widespread the flood threat will be.

.SPOTTER INFORMATION STATEMENT...

Limited spotter activation may be needed this afternoon and
evening.