452
FXUS61 KLWX 151345
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
945 AM EDT Sun Jun 15 2025

.SYNOPSIS...
Daily chances for showers and thunderstorms with the risk of
localized flash flooding look to continue through early next week as
a stalled frontal boundary remains nearby. The coverage of showers
and thunderstorms decreases today through Monday for most of the
area outside of central Virginia. A warm front lifts back through
the area Tuesday into Wednesday with a strong cold front to follow
late week.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The stalled frontal boundary seems to have pushed a bit more to
the south/west this morning as clouds and north/northeast winds
have increased in the central Shenandoah Valley. Based on 9AM
satellite and surface obs, the wavy front likely stretches from
Garrett County south to the Shenandoah Mountains, then southeast
to near Farmville, VA, to just south of Virginia Beach along the
VA/NC border.

A pronounced CAD wedge remains in place to the east/north of
the boundary, and it is likely to stick around all day. The 12Z
IAD sounding only has around 10 knots of wind in the boundary
layer, with weak winds atop it. The near-surface easterly flow
from building high pressure well to our north continues to
reinforce the wedge. This keeps highs well below normal in the
upper 60s to 70s this afternoon.

To our west, a broad surface low over western WV will move along
the frontal boundary toward the central Appalachains. Several
ripples of upper level energy continue to traverse atop the
surface boundary. This will help fuel widespread shower and
thunderstorm activity later today for areas along/south/west of
the boundary, along with instances of flash flooding.

The boundary is likely to push a bit more eastward this
afternoon as the surface low tracks east as well. Once again
looking at multicellular clusters developing between 2-10pm
along the boundary before waning after late this evening. Storms
will fuel off of MUCAPE values of 500-100 j/kg with 0-6 km
shear values under 35 kts. Rain rates of 1-2"/hr remain possible
with PWATS still hovering between 1.5 to 2 inches. Flood Watch
remains in effect for the Alleghenies and portions of Central
VA.

To the east, conditions remain dry through this afternoon,
with intermittent drizzle possible. Leftover convection spills
east of the mountains this evening, especially along and south
of I-66/US-50.

Showers and thunderstorms diminish tonight as areas of fog and
low clouds persist. Lows tonight fall back into the low to mid
60s. A few upper 50s are possible in the river valleys and areas
along the PA/MD line as slightly drier air works in.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/...
High pressure over eastern Canada and northern New England will
shunt a stationary boundary south of the region. Onshore
maritime flow will continue as a result with multiple pieces of
shortwave energy traversing the boundary to the south. The
stalled front will remain close enough for increased chances of
shower activity especially south of the Baltimore/DC metro
areas. Highest shower chances will be during the early morning
and late afternoon/evening hours. Once again isolated instances
of flash flooding are possible given the antecedent conditions
over the last few days. Warm stratiform rain processes will be
more of the theme compared to convective due in part to a
slightly more stable airmass overhead. Highs Monday will remain
in the upper 60s and low to mid 70s with the influence of high
pressure along the New England coast still wedging south and the
front slowly push back north from central and southern VA.

The stalled surface boundary that will have lingered over the area
for several days will finally start to dissipate and lift north of
the area as a warm front Tuesday into Wednesday. Meanwhile, a weak
upper trough will approach from the Ohio Valley. Showers and
thunderstorms are expected to form during the afternoon hours within
a very humid airmass (surface dewpoints around 70). High
temperatures on Tuesday are expected to be reach into the upper 70s
and lower 80s for most.

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
High pressure strengthens offshore moving into the middle of the
week, leading to south to southwesterly low-level flow and
increasing heat and humidity locally. Temperatures should reach into
the 90s on both Wednesday and Thursday. When combined with dewpoints
in the lower 70s, heat indices may approach 100 on Thursday.
Thunderstorms appear possible both days, but the greater coverage
should be on Thursday as an upper trough tracks off to our north
across the Great Lakes, with its associated cold front approaching
from the west. Current model guidance suggests that ample
instability and shear may be present on Thursday, so some storms may
be on the stronger side. Upper troughing is expected to dig in from
the Great Lakes on Friday. Cooler and drier conditions are expected
locally in the wake of the system`s cold front heading into next
weekend.

&&

.AVIATION /13Z SUNDAY THROUGH THURSDAY/...
Widespread low stratus is expected to persist for the entire day
at all of the terminals. IFR CIGs this morning rise to above
1000-1500 feet this afternoon, but skies remain overcast. It is
possible that clouds break enough at CHO for a brief period of
VFR conditions this afternoon.

Another round of showers and thunderstorms is expected this
afternoon to evening, with the highest concentration of activity
south of a line form KEKN to KCHO/KSHD and KRIC. Storms look to
bubble in these aforementioned locations between 19-02z/3-10pm.

Elsewhere, some evening heavy showers and a few thunderstorms
are possible. Any storm will be capable of producing heavy
downpours, frequent lightning strikes, and gusty winds. Convection
slowly wanes after 00z-04z/8pm-12am. IFR/sub-IFR cigs/vsbys are
expected across all terminals tonight into Monday morning as
onshore flow remains.

Additional periods of sub-VFR conditions are likely to continue
for Monday and Tuesday. Shower and thunderstorm chances will
remain during the afternoon and evening hours especially at
terminals south and east of KCHO Monday before becoming more
scattered areas wide as the front lifts northward Tuesday. Areas
further north will remain in a marine airmass with persistent
low clouds and areas of fog/low clouds during the
overnight/early morning periods.

Sub-VFR conditions may be possible Tuesday morning, but improvement
back to prevailing VFR conditions is expected Tuesday afternoon
through Wednesday. Temporary drops to sub-VFR conditions may be
possible in thunderstorms both Tuesday and Wednesday afternoon.

&&

.MARINE...
A stalled front will sit south of the waters today through Monday.
Onshore easterly flow will persists with occasional gusts up close
to SCA levels this morning and into the afternoon/evening hours.
This is especially true over middle and lower portions of the
Chesapeake Bay compared to the sheltered harbors/inlets.

Some marine fog is possible tonight given the moist airmass in
place. Less shower and thunderstorm activity is also expected
today through Monday given the proximity of the boundary south
of the region. Even with that said, an isolated shower or
thunderstorm cannot be ruled out during the afternoon and
evening hours. Sub-SCA level winds less than 15 kts are expected
through Monday.

Sub-SCA level southerly winds are expected over the waters on both
Tuesday and Wednesday.SCA conditions look to return Thursday
into Friday as a strong cold front crosses the waters.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Flood Watch from noon EDT today through this evening for
     MDZ501-502-509-510.
VA...Flood Watch from noon EDT today through this evening for
     VAZ025-026-036-037-503-504-508.
WV...Flood Watch from noon EDT today through this evening for
     WVZ055-501>506.
MARINE...None.

&&

$$

SYNOPSIS...EST
NEAR TERM...KRR/EST
SHORT TERM...EST
LONG TERM...KJP/CPB
AVIATION...KRR/EST/CPB
MARINE...EST/CPB