505
FXUS61 KLWX 110750
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
350 AM EDT Wed Mar 11 2026
.WHAT HAS CHANGED...
Becoming increasingly concerned about the threat for dangerous
fire weather conditions Thursday through the weekend, with
Friday and potentially Saturday looking especially concerning.
A detailed fire weather discussion was added to focus on this
threat.
&&
.KEY MESSAGES...
- 1) Severe Thunderstorms are possible this afternoon and
evening.
- 2) A series of cold fronts crossing the area into early next
week will lead to multiple temperature swings.
&&
.DISCUSSION...
KEY MESSAGE 1...Severe Thunderstorms are possible this afternoon
and evening.
Today`s forecast remains a very challenging one in regards to
the potential for severe thunderstorms. At this point, there`s
a wide range of potential solutions on the table, with very low
confidence in which solution will ultimately verify.
However, ahead of any thunderstorm threat, very warm
temperatures again this afternoon with temperatures in the upper
70s to lower 80s. Record high temperatures may again be in
jeopardy (see Climate section below for more information). This
is ahead of a powerful cold front, which will bring a substantial
change to the weather thereafter.
Now, shifting gears to the more pressing topic, which is today`s
severe weather threat. First, current conditions differ a bit
from the previous forecast, with no morning convection to deal
with at this time anywhere in our forecast area. Looking
upstream though, a piece of shortwave energy branching off of
the southern stream energy over the southern Plains sparked a
few showers overnight across the MS River Valley, but those
never really got going. However, there is some cloud debris from
this activity that is heading in our general direction,
currently over the OH Valley. The more potent convection has
generally followed the evolution portrayed form the 00z NAM,
keeping us clear from convection this morning, unlike some of
the global guidance. Latest runs of the HRRR are also capturing
this pretty well, so at least for now, that may be a good point
to start from. Now, looking into the future, there is still a
great deal of uncertainty with the evolution today, but the lack
of substantial convection this morning does lend me to believe
that we don`t get completely capped today, so will lean
generally in that direction with this morning`s forecast.
The primary feature at play today is a potent northern stream
trough, which will continue to amplify as it tracks eastward
from the Northern Plains toward the Great Lakes today. A
corresponding surface low will deepen as it tracks northeastward
from Lower Michigan across the Lower Great Lakes and into the
St. Lawrence Valley. The low-level mass response to the
deepening cyclone will lead to strengthening low-mid level
winds, as a 700 mb jet of 50-70 knots develops over the Ohio
Valley this morning before spreading over our area by peak
heating this afternoon. Southerly flow at low-levels will draw
deeper moisture (low 60s dewpoints) northward into the area,
which when combined with daytime heating (surface temps climbing
into the upper 70s and lower 80s) will lead to surface-based
destabilization (MLCAPE values around 500-1500 J/kg). Assuming
that storms occur, the environment in place with MLCAPE values
of 500-1500 J/kg, steep lapse rates, and effective bulk shear
values of around 50 knots (with nearly all of it below 700 mb)
will be very favorable for the development of severe storms.
Per the most recent guidance, and using the guidance with the
best current initialization, this is the current thinking for
convective evolution today. First, the showers over the OH
Valley are beginning to increase in coverage, but are generally
moving towards PA and should largely stay north of our are this
morning. Some clouds are likely to move into our area as a
result. The biggest question is, will they clear out enough to
realize the aforementioned CAPE value this afternoon? Looking at
forecast soundings, even in those that don`t really initiate
convection, leads me to believe we will, and that the storms
moving out of central WV into our region by early-mid afternoon
do have a decent chance to maintain or redevelop on our side of
the Allegheny Front. Assuming this does happen, the available
shear/instability support both multicell structures, as well as
discrete supercell structures. All hazards will be possible,
including tornadoes with any storms this afternoon. The
environment in place will make damaging winds possible with any
storms that form. However, that threat would likely be maximized
in scenarios that produce a more linear convective mode, with a
QLCS or smaller bowing segments. A more cellular mode would
likely lead to supercells, a greater threat for both severe hail
and tornadoes, and lesser areal coverage of damaging winds
compared to a linear mode. Storms spread east through the
afternoon and towards the I-95 corridor by this evening. The
eastward extent is also in question, and will likely depend on
what from convection takes.
The Storm Prediction Center maintained the SLGT risk for severe
today, but did expand their 5% tornado probability outline for
most of the area, and maintained the CIG1 hatching area
(suggesting a reasonable maximum tornado intensity of EF-2, if a
tornado were to occur). That hatched area with 5% probs is an
indication of the level of uncertainty still in the forecast,
but also the high-end nature if things do tailor towards the
worst-case scenario. They also have a 5 percent hail contour,
and a 30% wind contour (which is driving the SLGT risk
category). There is no CIG 1 hatching for wind, but hurricane
force gusts (74+ mph) are needed to justify wind hatching. It
wouldn`t be a shock to see some 60-70 mph gusts in any bowing
segments.
The main line of showers that will accompany the actual cold
front itself will largely fizzle into showers with a shift in
synoptic winds in its wake. This is because it comes through
overnight, with no instability left to work with.
A brief summary of the main takeaways follows below:
-Forecast uncertainty is very high tomorrow. Plausible scenarios
range from no severe thunderstorms at all, to a very impactful
severe thunderstorm event.
-Any storms that do form this afternoon will likely turn
severe, posing at least a threat for damaging winds, and
potentially large hail and tornadoes too (if the storm mode is
supercellular).
-The timing of the most intense storms is expected to be in the
afternoon and evening hours, with the strongest storms (if
they occur at all) expected to move through the I-95 corridor
between roughly 3 and 8 PM.
-A squall line will likely approach from the Ohio Valley and
track toward the Alleghenies tomorrow evening, but will likely
be weakening as it does so. Any severe threat with this line
will likely stay confined to along/west of the Allegheny Front.
KEY MESSAGE 2...A series of cold fronts crossing the area into
early next week will lead to multiple temperature swings.
Temperatures take a 15 to 30 degree dive Thursday as gusty west
to northwest flow ramps up. Confidence is a bit higher here for
the wind given the residual gradient/high pressure returning
from the south. A non-diurnal temperature spread is expected
with highs ranging from the upper 30s over the mountains to
upper 50s along and east of I-95.
A progressive mid-latitude pattern will allow a myriad of short and
longwave troughs to trek across the country. Such a regime supports
marked temperature swings as the associated cold fronts push toward
the Eastern Seaboard. The peak in the warmer phase of this pattern
would be on Sunday before temperatures come crashing down into next
week.
A compact upper trough pushing across the Great Lakes toward eastern
Canada will carry a deep cyclone with it. Global guidance keep the
low track mainly near/north of the international border with Canada.
Given how far the forcing is from the local area, expect a few
showers across the Alleghenies on Friday, but otherwise most of the
area remains dry. The robust wind field with the trough will make
for breezy conditions on both Friday and Saturday. Given the higher
winds are aloft, the strongest gusts should be confined to mountain
locales.
There has been a trend in the guidance toward warmer conditions for
Sunday as highs rise well into the 60s. However, an even more
pronounced system swings across the eastern U.S. late Sunday into
early next week. In response, global ensemble solutions show a
marked fall in temperatures. This brings a return to more winter-
like conditions for the early/mid portions of next week.
&&
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
A strong cold front will bring the return of sub-VFR conditions
at times, starting this afternoon and continuing through early
Thursday. Showers and strong to severe thunderstorms may impact
the terminals during this time. Lots of uncertainty regarding
coverage of storms, but if they do develop, they will likely be
severe Wednesday afternoon/evening, with damaging winds and
large hail being the main threats. An isolated tornado or two
cannot be ruled out as there will be plenty of wind shear.
Outside of the shower and thunderstorm threat will be the wind.
Expect gusty south to southwesterly winds up to 25 kts today
switching to the northwest with gusts 25 to 35 kts Thursday
afternoon.
Expect largely VFR conditions on Friday into Saturday with any
precipitation threats to the west of all TAF sites. The bigger story
will be the gusty winds on Friday ahead of another strong cold
front. Ahead of this system, expect southerly gusts to around 25 to
30 knots before winds shift to west-northwesterly into Saturday
and decrease throughout the day.
&&
.MARINE...
SCA conditions start by midday in southerly channeling and
continue through tonight ahead of the frontal passage. Gusts of
20 to 25 kts are possible, especially over the open and middle
waters of the Chesapeake Bay/tidal Potomac River. Some severe
storms may develop out west and make their way towards the
waters early this evening. Severity may be decreasing as they
approach the waters towards sunset, but SMWs may be needed.
Still a lot of uncertainty with coverage of storms and if they
make it to the waters, but just something to be mindful of in
planning today.
A strong cold front will cross the waters late tonight into
Thursday. This will lead to a few gusty showers/t-storms (SMWs
may be needed again as these push through) and gusty post-
frontal north to northwest flow. Gusts of 25 to 35 kts can be
expected with even some northerly channeling over the northern
Chesapeake Bay. Winds will gradually decrease Thursday night
into early Friday morning.
Ahead of a strong cold front, southerly channeling effects will lead
to increasing wind fields across the area waterways. Gusts up to
30 to 40 knots are possible on Friday, especially over the
Chesapeake Bay. Small Craft Advisories will be needed for Friday
into Friday night, with Gales possible.
Winds diminish some behind the front with mainly west-northwesterlies
on Saturday.
&&
.FIRE WEATHER...
Thursday through Saturday look concerning in regards to fire
weather, especially Friday. However, the threat will be
conditionally based upon how much rain the region receives this
afternoon through Thursday morning. The current forecast
precipitation amounts are around a quarter inch east of the Blue
Ridge, as well as along the MD/PA border. Higher amounts are
expected along/west of the Allegheny Front, with 0.75 to 1.25
inches in the forecast. In between, specifically within the
Shenandoah Valley and portions of the Potomac Highlands is where
I`d be concerned about a bit of a rain shadow. Also, given the
showery nature of this afternoon`s potential activity, these
amounts likely won`t be realized at every given location. All
this to say, while some areas could see enough rain to keep
fuels damp through this upcoming windy period, many will not.
Now, moving into Thursday afternoon, following a strong frontal
passage winds will pick up substantially out of the WNW along
with a sharp decrease in RH. Current forecast in the Shenandoah
Valley/Potomac Highlands drops RHs within the valleys into the
20s and low 30s, but model guidance suggests that could even be
high. This will also be paired with sustained winds around 15-20
mph (20-25 at elevation) with gusts of 30 mph (40 mph at
elevation). The sun will be out during the afternoon in these
areas, but temperatures will actually be on the decline (mid 40s
in the valleys, mid 30s on the ridges). This, paired with the
recent rainfall, make Thursday less of a concern, but still
worth noting for any ongoing fires.
Friday is where the level of concern increases. Another strong,
and this time dry, cold front will be approaching the region
before moving through Friday night. Ahead of that, very strong
southerly winds pick up, with values 5-10 mph stronger than
Thursday possible. The air mass will also continue to be
extremely dry, and could be locally enhanced in downslope flow
west of the Blue Ridge. Current forecast has low to mid 20s RHs
in the typical drier valleys. Given that the winds likely have
dried things out substantially from any rain the day prior, this
looks to be a concerning day in regards to fire weather. Future
shifts may need to consider Fire Weather Watches.
Saturday may actually be the driest day, behind the frontal
passage from Friday night. RH values could drop into the teens
across much of the area. Winds will be on the decline, but will
remain somewhat elevated, especially along/north of the
interstate 66 corridor, where 15-25 mph winds can be expected.
More analysis will need to be done to determine the threat for
any headlines Saturday, but could see something being necessary
on this day as well.
Gusty winds but increasing RHs on Sunday ahead of another front,
which looks to bring wetting rains Sunday evening/night. Less of
a threat Sunday, but any ongoing fires could feel the impacts of
some gusty southeasterly flow (20-25 mph gusts).
&&
.CLIMATE...
Daily high records could be set again today.
Below is a list of previous records for March 11.
Washington DC (DCA)
Date March 11
Record High 79F/2021
Record Warm Low 57F/2016
Washington-Dulles (IAD)
Date March 11
Record High 7F/2021
Record Warm Low 49F/1967
Baltimore (BWI)
Date March 11
Record High 79F/2021
Record Warm Low 53F/1955
Annapolis (NAK)
Date March 11
Record High 74F/1967
Record Warm Low 52F/1986
Charlottesville (CHO)
Date March 11
Record High 83F/1925
Record Warm Low 53F/2016
Martinsburg (MRB)
Date March 11
Record High 78F/2021
Record Warm Low 49F/1955
Hagerstown (HGR)
Date March 11
Record High 79F/2021
Record Warm Low 53F/2016
Baltimore Inner Harbor (DMH)
Date March 11
Record High 76F/1967
Record Warm Low 56F/2016
56F/1955
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...Small Craft Advisory from 2 PM this afternoon to 6 AM EDT
Thursday for MDZ008.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 2 PM this afternoon to 6 AM EDT
Thursday for ANZ530>543.
&&
$$
DISCUSSION...BRO/DHOF/CJL/KJP
AVIATION...CJL/KJP
MARINE...CJL/KJP
NWS LWX Office Area Forecast Discussion