720
FXUS61 KLWX 160847
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
447 AM EDT Thu Jul 16 2026

.WHAT HAS CHANGED...
Lowered temps for today in coordination with adjacent WFOs. All
agreed on no heat headlines. Still hot, but likely short of
advisory criteria.

&&

.KEY MESSAGES...
- 1)High heat and hazy skies look to continue through Friday.

- 2)Thunderstorm chances increase this weekend and could potentially
linger into Sunday as a front drops into the region.

&&

.DISCUSSION...
KEY MESSAGE 1...High heat and hazy skies look to continue through
Friday.

Opted not to issue any HYY today in coordination with
neighboring WFOs. Still hot, but likely short of criteria for
most of a given zone. Main reasoning was thickness of the
Canadian wildfire smoke limits mixing. Similar conditions are
expected Friday making the temp/heat index forecast more
complex as an even thicker plume of Canadian wildfire smoke
descends upon the region.

Smoke concentrations will continue to increase Thu as an
additional wave of smoke is sent southward from fires raging
over Quebec and western Ontario. With that said, hi-res guidance
(such as the RRFS-A and HRRR) hint at some slightly lower air
temps and higher Tds today and Fri which could negate the need
for heat headlines. This will be something that will need to
monitor given what played out earlier today with the smoke aloft
and subdued mixing. With the smoke, will come a few more days
of poor air quality.The respective air quality agencies in MD
and VA have issued Code Orange Air Quality Alerts for the
DC/Baltimore metros today with additional alerts likely Fri as
air quality worsens.

In addition to the heat and smoke/poor air quality will be the
concern for a few isolated showers/strong t-storms. SPC has a
Marginal Risk (Level 1 out of 5) along the Mason Dixon today.
Height falls/PVA will be negligible as most forcing for ascent
will be associated with shortwaves in cyclonic flow passing to
the N/NE. However, a halt in height rises paired with a slowly
swrd sagging cold front and potentially bay breezes in areas
where low-level flow goes weak in the vicinity of the front, may
be enough when coupled with heating to result in a couple of
isolated t-storms. There is further uncertainty given continued
smoke aloft, as that could hamper heating and
instability/convective initiation.Upstream over NE PA into NJ
and the NYC tri-state area from earlier today may offer a clue
as we will be in a similar environment across the MD/PA border
Thursday afternoon. Any storms that manage to develop will have
ample MLCAPE (2000-3000 J/kg) and DCAPE (1000-1500 J/kg) to work
with, as well as notable flow in the mid and upper levels for
mid July (40-50+ kts). If any storms manage to develop by late
afternoon, they could at least briefly congeal into a small
cluster and propagate south/ southeast toward and across the
Chesapeake Bay during the evening hours. Damaging winds would be
the primary (conditional) risk, but large hail is also possible
given ample CAPE, shear, and low seasonably low wet-bulb zero
heights around 11.5 kft. Any storms that we do see will help
scrub out some of the smoke and improve air quality.

KEY MESSAGE 2...Thunderstorm chances increase this weekend and could
potentially linger into Sunday as a front drops into the region.

SPC has entire CWA in Slight Risk (Level 2 out of 5) on
Saturday... previous discussion follows.

The surface front will drop further southward Fri. Additional
smoke likely mixes into the region. Any convection on Fri will
likely be limited to the higher terrain as the front washes out
and pairs with orographic lift. Again, any storm that does form
could be on the strong side.

Fri night, the aforementioned front will begin to lift north
ahead of a wave of low pressure and stout shortwave approaching
from the Upper Midwest/Great Lakes. Increasing MLCAPE late at
night with some moisture advection and modest low-level flow
overtop the front may result in a few t-storms heading into
early Sat morning, especially east of the Blue Ridge where a
bit richer low-level theta-e ridge looks to pivot through.

Forcing and shear will be ample on Sat, but the amount of
instability is in question due to potential morning precip.
Should enough instability develop, svr wx is possible with all
hazards (damaging straight-line winds, large hail, a few
tornadoes, and isolated instances of flash flooding) on the
table. This aligns with CSU/NSSL/CIPS probabilities which
suggest a 5 to 15 percent probs of svr wx during the weekend
period. If the front does not make it entirely through the area,
repeated strong storms will be possible on Sun.

After a brief lull possible on Mon, another strong wave may
approach by the middle of next week.

&&

.AVIATION /08Z THURSDAY THROUGH MONDAY/...
VFR & mostly dry conditions will likely continue through Fri.
Smoke aloft will result in a hazy appearance of the sky through
Fri. Vsby reductions of 5-6 SM are possible corridor today and
Fri with lower vsbys (2-4 SM) tonight into Fri, especially NE of
IAD/DCA as smoke mixes south and closer to the sfc behind a
weak front. Winds will vary between N/NW and SW over the next
few days as that front sits nearby. A t-storm can`t be ruled out
this late afternoon and evening, mainly east of the Blue Ridge
and in nrn MD but confidence is very low. Did add a PROB30
between 20-24z at both BWI/MTN where the confidence seems the
highest for storm development off the bay breeze. Can`t rule out
a t-stprms near the mtns Fri afternoon.

Periods of sub-VFR restrictions can be expected this weekend
in any t-storms. The greatest coverage of storms likely Sat
potentially lingering into Sun. Expect early morning low CIGS or
patchy fog with afternoon/evening convection. Winds will remain
light overall with chaotic motions in around t-storms.

&&

.MARINE...
Winds will waver between N/NW and SW over the next few days as a
cold front dangles near the waters. Depending on the strength of the
front and how far N or S it pushes, there may be brief/marginal
periods of SCA level gusts, though these currently appear too
brief with certainty too low for any headlines at the moment. A
couple of t-storms can`t be ruled out along the cold front this
late afternoon and evening, and anything that does manage to
form could produce rather gusty winds.

More widespread t-storm activity and the need for SMWS will be
needed over the weekend as a cold front approaches. S`ly
channeling also returns to portions of the waters Sat into Sun.

&&

.CLIMATE...
Well above normal temperatures will persist through Thursday.

Below is a list of record daily high and warm low temperatures for
July 16 (Thursday).

=================================================================
July 16 Record Daily High/Warm Low Temperatures
=================================================================
Baltimore MD 104 (2024, 1988) 78 (1879) Washington DC 104
(2024, 1988) 84 (1983) Sterling-Dulles Airport VA 104 (1988) 74
(2013) Baltimore (Downtown) MD 105 (2024) 85 (2013) Annapolis MD
98 (1997, 1900) 79 (2024, 2013, 1955) Hagerstown MD 104 (1988)
76 (2024) Martinsburg WV 107 (1988) 77 (1983) Charlottesville VA
102 (1988) 82 (1983)

Period of Record (POR) information (records since):
Baltimore MD - July 1872
Washington DC - January 1872
Sterling - Dulles Airport VA - January 1960
Baltimore (Downtown) MD - July 1950
Annapolis MD - January 1894
Hagerstown MD - January 1899
Martinsburg WV - January 1891
Charlottesville VA - January 1893

&&

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

&&

$$

DISCUSSION...CPB/EST
AVIATION...CPB/EST
MARINE...CPB/EST