363
FXUS61 KLWX 111928
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
328 PM EDT Thu Jun 11 2026
.WHAT HAS CHANGED...
Added another Heat Advisory for the same area on Friday.
Additionally, added some new details/observations regarding
today`s severe weather threat. Made a few changes to the Friday
severe weather threat as well, just to bring in some model
uncertainty.
&&
.KEY MESSAGES...
- 1) Hot and humid conditions persist through Friday with a
daily threat for strong to severe thunderstorms.
- 2) Shower and thunderstorm chances return late Sunday into
next week as a cold front moves through the region.
&&
.DISCUSSION...
KEY MESSAGE 1...Hot and humid conditions persist through Friday
with a daily threat for strong to severe thunderstorms.
Today presents a complex convective forecast, with a high end
potential for severity, but a very low confidence in if/how many
storms develop. Starting at the surface this afternoon, it seems
like many things are in favor of storms today. Temperatures are
currently well into the 90s, with dew points rising into the
70s which is yielding MLCAPE values in excess of 2000 J/kg.
Even more impressive is the pooling of 3000+ J/kg of MLCAPE
pooled along the Chesapeake Bay. There is a surface trough
located along the Blue Ridge roughly, with winds out of the SW
to the east, and more westerly to the west of the boundary.
Per the latest ACARS sounding data, westerly flow is prevalent
at the surface and in the mid-levels, which could inhibit
convection for much of the afternoon. Thinking that development
on terrain circulations is less likely due to this fact, but
some development is slightly more likely along the Bay Breeze.
However, the area to watch closely is the convection developing
along a remnant MCV from this morning over the Ohio Valley. This
activity will eventually push into the region later this
afternoon/evening, likely becoming the primary threat for
severe weather today. As storms are already developing, timing
has come a bit more into focus, and is trending a bit later, and
several hours later compared to what we saw last evening. What
this convection does over the Allegheny Front is largely going
to depend on the mode it crosses in. If it is still not well
developed, it may struggle to maintain itself in the mid-level
westerlies. However, if this activity develops into an
established squall line, then it should be able to maintain
itself as it moves into an even more unstable airmass over our
region. As the wave of energy moves into the much more robust
environment near/east of I-95, storms may become more vigorous
again, possibly congealing into small clusters with a damaging
wind and sporadic large hail threat. One concerning thing is
just how much DCAPE is available for very strong downdrafts
today (around 1000-1200 J/kg). This is substantial, and has me
concerned for a few significant gusts if things do manage to
organize into bowing structures especially. Still, this threat
is not guaranteed, which is why POPs are not higher for this
event. However, given the potential higher end nature should it
materialize, keep a very close eye on the forecast this evening.
Thunderstorm activity should wind down late this evening, though
with the residual warm and humid airmass in place a pop up
shower or even a bit of thunder can`t be ruled out overnight.
Outside of the convective potential today, the other big issue
is going to be the heat, as heat indices are into the 100s for
most. Near and east of I-95, slightly more humid air to the
east of the trough and closer to the Chesapeake Bay has heat
indices near/above 105, peaking mid afternoon. It will be hot
regardless, so make sure to stay hydrated and avoid strenuous
activity during the heat of the day.
Heat and humidity lingers Friday, and unless there is a lot of
morning cloud cover it looks to be a bit hotter. There is the
potential for a bit more mixing down of lower dew points given
lingering westerly flow, but heat index values likely approach
100 to 105 again in the afternoon. For now, have highlighted the
same areas in a Heat Advisory for tomorrow as was highlighted
today. Could see an expansion west being possible, but given the
potential for lower dew points compared to today, this was a
good first stab at it, and will allow further shifts to make a
final call on the westward extent. However, as always, just
because an advisory may not be in effect for all areas, it will
be very hot/humid either way, so all should take proper
precautions once again.
Stronger forcing associated with an upper trough glancing by to
the northwest and an approaching cold front lends to higher
certainty of more numerous thunderstorms Friday afternoon and
evening. Flow aloft will tick up slightly, though still modest
and out of the W to WNW. There is some concern with the amount
of spread amongst the model guidance as to where the best
coverage is. Many of the hi-res models thus far keep convection
suppressed to the south, likely due to that westerly flow aloft
potentially stifling convection. However, with abundant
instability in place once again, am thinking that storms may
once again develop as they move east of the I-81/Blue Ridge
corridor as they run into the most favorable airmass. Given the
amount of instability in place once again, thunderstorms may
produce some rather gusty winds. Severe/damaging wind gusts are
plausible, especially with the added forcing that should help
force storms into bands. Isolated large hail is possible with
the most intense updrafts, and again could see the potential for
some significant wind gusts.
Thunderstorm activity should wind down by the evening hours.
Following the Friday night cold frontal passage, high pressure
will briefly pivot over the Mid-Atlantic for Saturday. This
results in notably lower humidity and temperatures several
degrees cooler (relatively speaking) as well.
More sun than clouds amid light northwest breezes are expected.
Temperatures falling into the 60s Saturday night with dew points
around 60 will feel like a stark contrast to the more oppressive
humidity in the preceding couple of days/nights.
KEY MESSAGE 2...Shower and thunderstorm chances return late
Sunday into next week as a cold front moves through the region.
A deep upper-level trough will form over the Great Lakes towards the
end of the weekend, resulting in a cold front that will track
through the East Coast between late Sunday and going into Monday.
There are a couple of ML models that show a severe risk for this
front, bringing back severe chances after a brief pause on Saturday.
Once this cold front moves through, we could begin to see a brief
dip in temperatures, with highs for Monday currently ranging largely
in the 80s. Although the low pressure system associated with this
front will push north by late Monday, another area of low pressure
could build towards the south and push north on Tuesday, bringing
additional chances for rain and showers. By this point, severe
chances become much more uncertain as instability looks modest,
but shear will increase. Overall, expect a repeating pattern of
frontal boundaries tracking through the region bringing several
opportunities for precipitation.
&&
.AVIATION /18Z THURSDAY THROUGH TUESDAY/...
Prevailing VFR conditions are expected through Friday.
Thunderstorm coverage is uncertain this afternoon and evening,
but any storm could contain very gusty winds or even some hail.
Storms look to fire later this afternoon relative to yesterday.
The 18Z TAFs honed in on a smaller convective window, though
still couldn`t waver from the PROB30s, as confidence is just too
low at this time.
There is a higher chance of strong to severe thunderstorms
Friday afternoon and evening as a cold front approaches. Added
that threat in as a PROB30 for now. There is still some
uncertainty amongst model guidance for now, but still thinking
the chances are higher tomorrow. Some of the high-res model
guidance just disagrees, so will have to see how the
evening/overnight guidance changes.
Winds will be fairly light out of the west or southwest both
days outside of any storms.
VFR conditions are predominantly expected through the weekend, with
some reduced conditions possible beginning Sunday evening associated
with potential showers and thunderstorms. Periodically reduced
conditions associated with a low pressure system could continue
through early next week. Gusts between 15-20 knots are possible
Sunday afternoon/evening before falling again Monday, with
southwest winds shifting easterly by Monday evening.
&&
.MARINE...
Generally light west to southwest winds are expected through
Friday, becoming northwest Friday night through Saturday. There
is a potential of at least brief near SCA conditions behind a
cold front Friday night into Saturday morning. Ahead of this
front, potential showers and thunderstorms bring a risk of
lightning and strong winds to the waters each afternoon/evening.
Both afternoons may need a few SMWs, with 50+ knot winds
possible in any storms.
SCAs will likely be needed Sunday evening with gusts up to 20 knots
possible, but should go back below SCA thresholds by Monday morning.
Southwest winds shift northerly Monday afternoon before shifting
southeast.
&&
.CLIMATE...
Temperatures are expected to soar to as much as 15 to 20 degrees
above average through Friday. This approaches or exceeds daily
record values at some sites.
Below is a list of record daily high and warm low temperatures
for June 11th and 12th (Thursday and Friday).
=================================================================
June 11th Record Daily Highs and Warm Lows
=================================================================
Site Record High Record Warm Low
DCA 101 F (set in 1911) 74 F (set in 2020 +6 others)
IAD 95 F (set in 2016) 72 F (set in 2005)
BWI 99 F (set in 1911) 75 F (set in 1914)
DMH 100 F (set in 1984) 79 F (set in 1984)
NAK 96 F (set in 2000) 79 F (set in 1973)
HGR 97 F (set in 1911) 73 F (set in 2005)
MRB 101 F (set in 1911) 71 F (set in 1927 and 1922)
CHO 99 F (set in 1911) 76 F (set in 2020)
=================================================================
June 12th Record Daily Highs and Warm Lows
=================================================================
Site Record High Record Warm Low
DCA 95 F (set in 2017 +6 others) 77 F (set in 2015)
IAD 96 F (set in 1986) 72 F (set in 1986)
BWI 96 F (set in 1986 and 1914) 77 F (set in 1947)
DMH 96 F (set in 2025 +2 others) 77 F (set in 2017 and 2015)
NAK 98 F (set in 1914) 77 F (set in 2000 and 1973)
HGR 92 F (set in 2017 +5 others) 71 F (set in 2010 +5 others)
MRB 97 F (set in 1938 and 1933) 73 F (set in 1914)
CHO 98 F (set in 1914) 72 F (set in 1947 +2 others)
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...Heat Advisory until 8 PM EDT this evening for DCZ001.
Heat Advisory from 11 AM to 8 PM EDT Friday for DCZ001.
MD...Heat Advisory until 8 PM EDT this evening for MDZ008-011-013-
014-016>018-508.
Heat Advisory from 11 AM to 8 PM EDT Friday for MDZ008-011-013-
014-016>018-508.
VA...Heat Advisory until 8 PM EDT this evening for VAZ054-057.
Heat Advisory from 11 AM to 8 PM EDT Friday for VAZ054-057.
WV...None.
MARINE...Heat Advisory until 8 PM EDT this evening for ANZ530.
Heat Advisory from 11 AM to 8 PM EDT Friday for ANZ530.
&&
$$
DISCUSSION...BRO/DHOF/CJL
AVIATION...BRO/DHOF/CJL
MARINE...BRO/DHOF/CJL
NWS LWX Office Area Forecast Discussion