Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

589
FXUS61 KLWX 310759
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
359 AM EDT Mon Aug 31 2026

.WHAT HAS CHANGED...
Increasing risk of severe weather mid week, while decreasing
risk of heat headlines.

&&

.KEY MESSAGES...
- 1) Scattered thunderstorms expected again today.

- 2) Near-record early September heat expected.

- 3) Thunderstorm chances increase this week, but timing remains highly
     uncertain.

&&

.DISCUSSION...

KEY MESSAGE 1...Scattered thunderstorms expected again today.

Low-level troughiness will remain in place through Tuesday and
should support development of widely scattered to scattered
afternoon thunderstorms in an increasingly hot and humid air
mass. The best chance for thunderstorms will be across the
northern half of the fcst area where most recent NUCAPS data
showed the higher 850 mb dewpoint air and from potential
thunderstorm clusters tracking southeastward in NW flow from
Pennsylvania into northern Maryland, but isolated thunderstorms
are also possible over the higher terrain of the Blue Ridge
Mountains. Convective activity should wane quickly after sunset
and dissipate by mid evening.

KEY MESSAGE 2...Near-record early September heat expected.

A strong mid-level ridge over the southern Plains will build toward
the Mid South during the early to middle part of the week. The
latest trend is for the ridge to build further east into the TN
Valley on Tuesday and Wednesday, then break down late in the week as
a strong trough digs down from southern Canada. Having the ridge
build to the east is going to keep hot and mostly dry conditions
over the region for longer.

Despite the uncertainties, it remains likely that high temperatures
will reach the lower to middle 90s for most of the area this week.
Latest guidance indicates potential for temperatures in the upper
90s to near 100 by mid week, so long as it is not disrupted by cloud
cover or convection. Depending on smaller scale details, dew points
could end up a little higher or lower than currently progged which
will ultimately affect how high heat index values get. Values
approaching Heat Advisory criteria (100-104 west of the Blue Ridge,
105-109 east of the Blue Ridge) are possible Tuesday through
Thursday. Similar heat and humidity could persist into Friday, but
there is a lot of uncertainty for the late week temperature forecast
due to possible convective systems moving through the area.

Temperatures may begin to moderate by next weekend as a cold front
crosses the region.

KEY MESSAGE 3...Thunderstorm chances increase this week, but
timing remains highly uncertain.

Disturbances rounding a ridge to the south and west in NW flow aloft
will introduce shower and thunderstorm chances at times this week.
Given the latest trend bringing the ridge further east during the
middle of the week, that should keep most of the convective systems
over NY/PA and the Northeast Tuesday and Wednesday. That does not
mean we are completely in the clear those days; if anything, the
highest chance of seeing thunderstorms will be in northeast Maryland
during the late afternoon to evening as storms move south from PA.
By Thursday, a strong upper trough digs south from Canada which will
rapidly break down the ridge overhead. As this occurs, our area is
going to be in a much more favorable location for upstream
shortwaves to pass overhead.

The enhanced lift and shear traversing the region besieged by
several days of hot and humid conditions will introduce the
potential for some significant severe weather. AI/ML guidance has
broad elevated probabilities of severe weather much of this week,
particularly Wednesday and Thursday. It should be noted that there
is a conditional potential for one or more organized clusters of
strong to severe storms at some point this week. The most likely
time currently appears to be either Wednesday or Thursday, but
changes are likely given uncertainty at this range. It is quite
possible given latest trends that the threat is highest Thursday and
Friday as the upper ridge breaks down more readily.

Storm chances may linger into next weekend as a cold front crosses
the region on Saturday.

&&

.AVIATION /07Z MONDAY THROUGH FRIDAY/...

Scattered thunderstorm development is expected this afternoon
with the main window between 18Z-00Z, although activity could
linger a little later across eastern terminals. Given low
confidence in location, only PROB30 groups were added to TAFs at
this time.

VFR this afternoon through Thursday for the most part. Timing,
coverage, and location will be the uncertainty each day and evening
for scattered strong to perhaps severe thunderstorms.
Any storms will bring brief MVFR to IFR conditions in terms of
downpours. Winds generally south to southwest 5 to 15 knots but very
gusty in strong thunderstorms. Can`t totally rule out some early AM
low clouds/fog either at times, but confidence is low.

&&

.MARINE...

Scattered thunderstorm development is expected this afternoon
and t-storms may be capable of producing strong wind gusts. SMWs
may be required.

Chances of thunderstorms increase throughout the week, so Special
Marine Warnings may be needed. Brief/marginal southerly channeling
can`t be ruled out each afternoon and evening.

&&

.CLIMATE...

Near-record heat is possible, peaking Tuesday through Thursday.

Below is a list of record warm temperatures for September 1, 2, and 3.

(A `+` indicates the record also occurred in previous years).

The period of record for most sites dates back to the late 1800s,
except for Sterling-Dulles Airport which dates back to 1960.

====================================================================
                            SEPTEMBER 1
====================================================================
Site                      Record Daily High   Record Daily Warm Low
Baltimore (BWI) MD           99 (1962)            78 (1932+)
Washington DC                99 (1980+)           77 (1980)
Sterling-Dulles Airport VA   98 (1980)            73 (2000)
Baltimore (Downtown) MD      99 (1973)            80 (2012)
Annapolis MD                 95 (1962)            78 (2018+)
Hagerstown MD               101 (1902)            72 (2018+)
Martinsburg WV              103 (1932)            73 (2000+)
Charlottesville VA          105 (1932)            78 (1932)

====================================================================
                            SEPTEMBER 2
====================================================================
Site                      Record Daily High   Record Daily Warm Low
Baltimore (BWI) MD           99 (1953)            75 (1932+)
Washington DC               101 (1980)            78 (1980)
Sterling-Dulles Airport VA   99 (1980)            72 (2020+)
Baltimore (Downtown) MD      98 (1980+)           80 (1980)
Annapolis MD                 97 (1998)            79 (2018+)
Hagerstown MD               100 (1953)            73 (2018+)
Martinsburg WV              103 (1932)            72 (2000+)
Charlottesville VA          105 (1953)            80 (1930)

====================================================================
                            SEPTEMBER 3
====================================================================
Site                      Record Daily High   Record Daily Warm Low
Baltimore (BWI) MD           98 (2023)            79 (1993)
Washington DC                98 (1953)            79 (1993)
Sterling-Dulles Airport VA   99 (2023)            77 (1993)
Baltimore (Downtown) MD      98 (2023)            82 (1993)
Annapolis MD                 99 (1993)            79 (2018)
Hagerstown MD               100 (1953)            72 (2018+)
Martinsburg WV              102 (1953)            71 (1957)
Charlottesville VA          104 (1953)            75 (1930)


&&

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

&&

$$

DISCUSSION...LFR/DHOF
AVIATION...LFR/DHOF
MARINE...LFR/DHOF