Bethesda, Maryland 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

169
FXUS61 KLWX 141830
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
230 PM EDT Sat Jun 14 2025

.SYNOPSIS...

A stalled to nearly stationary front will remain around the
region through Wednesday before lifting northward as a warm
front. A cold front will bring another round of rain toward the
end of next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
A nearly stationary boundary remains in place over our region this
afternoon. Based on wind observations and temperature gradients, the
front is located somewhere around the Potomac River and through the
DC metro. Clouds remain thick overhead, but low level cloud cover is
slowly scouring out along and south of the DC metro. An interesting
weatherish phenomenon is occurring in the northern part of our region
this afternoon due to a fire in New Jersey. Smoke from the NJ fire
has shifted southward into parts of northern MD, with the highest
concentration up in NE MD and the Baltimore metro. Smoke is getting
locked in near the surface due to a strong stable layer which is not
allowing for the smoke to get mixed out. The concentrations of smoke
are high enough that they are causing poor air quality with code red
air quality alerts being issued by the EPA and MD MDE.

Models have a mesolow forming along the stalled boundary this
afternoon creating showers and thunderstorms that will pass through
parts of our region late this afternoon and into this evening. Model
soundings are indicate a well saturated boundary layer with PW`s
approaching 2 inches and CAPE hovering between 1000 j/kg and 2000
j/kg. MBE`s are expected to be relatively low which could lead to
slower storm motions. The combination of high PW`s, over 1000 j/kg
CAPE, and a saturated boundary layer coupled with the mesolow will
lead to environment favorable for efficient rainfall production.
Rain rates within thunderstorms will likely be the 2 to 4 inch per
hour range with instantaneous rain rates approaching 6 inches per
hour.High rates combined with urban runoff/ a saturated environment
will lead to an increased threat for flash flooding.

Rain amounts will likely be between 0.5 and 1.5 inches with
reasonable worse case totals approaching the 2 to 4 inch range. I
would not be surprised if somewhere observes localized rain total
over 4 inches and as high as 6 inches. High end flash flooding will
be possible if the higher end rain totals/ rain rates are realized.
A Flood Watch for flash flooding is in effect for the majority of
the region east of the I-81 corridor.

In terms of timing and best threat area this afternoon/evening, the
HRRR and 3km NAM have been consistently showing a cluster of
thunderstorms impacting the DC metro and parts of the Baltimore
metro. Models generally have the storms approaching from the
northwest, but there are hints that another round could approaching
DC from the south. Based on model trends, the window for
thunderstorms in the DC and Baltimore metro would likely be between
5 pm and 11 pm this evening with the mostly likely window being
between 6pm to 10 pm.

A second area of concern will be parts of central Virginia and
eastward where heavy showers and thunderstorms could impact areas
that observed rain on Friday. The threat window for this area would
be slightly earlier from 4 pm through 9 pm.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/...

Not much of a change in the forecast as a pesky stalled front
remains nearby. The good news is that Sunday appears drier although
cloud cover will remain due in part to onshore easterly flow from
strengthening high pressure off the New England coast. This high
pressure system looks to force the frontal boundary further south
into central and southwest VA Sunday morning into SUnday midday.
Subsidence behind shortwave low pressure from Saturday evening will
also promote a decrease in PoPs as well for at least 2/3rds of the
forecast region. Even with that said, the risk for showers and
thunderstorms will still remain from the far western portions of the
Alleghenies south and east into central and eastern VA. This lines
up with both 00z CAM and synoptic guidance very well with the front
subdued to the south as jet max energy squirts east and high
pressure wedges in from the north. Once again, flash flooding will
be the primary concern with any showers and thunderstorms that
develop given the antecedent conditions. Locally damaging winds
cannot be ruled out as well with SPC maintains a Day 2 Marginal Risk
for portions of the VA Piedmont mainly along and south of I-64.
Highs Sunday will push into the upper 60s and low 70s with easterly
flow on the sable side of the boundary. LOcations along and south of
I-64 will sit in the mid to upper 70s to around 80 degrees.

The boundary works slowly back to the north Monday bringing
continued chances for showers and thunderstorms. Severe weather does
not appear to be an issue as stable marine air will be slow to erode
over the region. 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. Overall coverage of showers and
thunderstorms will be scattered with a focus mainly south and east
of metro areas. Convection chances increase again Tuesday as warmer
air works back into the region.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...

The surface boundary over the area finally starts to dissipate and
lift north of the area come Tuesday, with a weak upper trough
approaching 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.

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.

&&

.AVIATION /18Z SATURDAY THROUGH THURSDAY/...

A stalled boundary over the central part of our region has led
to widespread aviation restrictions. IFR ceiling conditions are
being observed north of the front toward the MD/PA border. More
MVFR ceilings are being observed toward the DC metro, but the
low level cloud deck is starting to scouring out. VFR conditions
are building into the DC terminals, but lower ceilings are
expected to return later this evening. Showers and thunderstorms
are likely to impact all terminals with heavy rain leading to
visibility restrictions likely in the IFR range and potentially
in the LIFR range at times. The main threat window for
DCA/IAD/BWI/MTN will between 5pm and 11pm, but based on guidance
the most likely threat window will be 6 to 10 pm. Once the
thunderstorms and showers exit our region, IFR ceilings are
likely to build over all terminals with MVFR visibilities due to
drizzle.

Additional periods of sub-VFR conditions are likely to continue for
both Sunday and Monday. Shower and thunderstorm chances will remain
during the afternoon and evening hours especially at terminals south
and east of KCHO. 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. Showers and thunderstorms are forecast to develop
each afternoon/evening, and these could result in brief sub-VFR
conditions if they move over a terminal.

&&

.MARINE...

A stalled front will remain draped across the waters through tis
evening. Winds today will switch from the south this morning to the
north and east later this afternoon into tonight. Some marginal SCA
northerly channeling is possible in the northern and middle part of
the bay later this afternoon and evening, but confidence is low.
Shower and thunderstorm chances are expected once again later this
afternoon and evening (mainly after 20z/4pm). Some storms may
warrant Special Marine Warnings with gusty winds and locally heavy
rainfall as the primary concerns. Any convection will wane over the
waters after 00z/8pm with passing showers, low clouds, and fog
leftover overnight. Less shower and thunderstorm activity can be
expected Sunday and Monday. Winds will remain out of the east on
both days at less than 15 kts.

Winds are forecast to remain below SCA levels through the middle of
the week. Daily afternoon showers and thunderstorms could pose a
threat to mariners from gusty winds and lightning strikes.

&&

.HYDROLOGY...

Model soundings and the SPC mesoanalysis are indicating that
PW`s will be maximized around or above 2 inches. The boundary
layer is forecast to be nearly saturated with CAPE values
between 1000 and 2000 j/kg. This environment will be favorable
for high rain rates with hourly rain rates approaching the 2 to
4 inches per hour with instantaneous rain rates as high 5 to 7
inches. The combination of high rates along with urban runoff/
saturated ground soils will lead to an increased threat for
flash flooding later this afternoon and into this evening. A
Flood Watch is in effect from 2 pm to 11pm this evening.

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Flood Watch until 11 PM EDT this evening for DCZ001.
MD...Air Quality Alert until midnight EDT tonight for MDZ006-008-
     011-014-507-508.
     Flood Watch until 11 PM EDT this evening for MDZ003>005-013-
     014-016>018-502>506.
VA...Flood Watch until 11 PM EDT this evening for VAZ025>031-
     036>040-050-051-053>057-501-502-505>508-526-527.
WV...Flood Watch until 11 PM EDT this evening for WVZ051>053.
MARINE...Air Quality Alert until midnight EDT tonight for ANZ530.

&&

$$

SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...JMG/EST
LONG TERM...KRR
AVIATION...JMG/KRR/EST
MARINE...KRR/EST
HYDROLOGY...JMG