Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

332
FXUS61 KLWX 011407
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
1007 AM EDT Tue Sep 1 2026

.WHAT HAS CHANGED...
No changes were made to the forecast.

&&

.KEY MESSAGES...
- 1) Severe weather risk increasing for the second half of the
     week.

- 2) Record high minimum temperatures likely this week, but
     record high maximum temperatures appear unlikely now.

- 3) Heat & thunderstorms begin to decrease towards the start of
     the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Severe weather risk increasing for the second half of the
week.

The upper ridge over the TN Valley is expected to build east
over the next 36 hrs with heights cresting over the local area
Wed afternoon. The ridge is expected to begin losing its grip
over the area during the second half of the week as upper trough
amplifies across the Northeast into the Mid Atlantic. Large
scale height falls are not forecast to occur over the area until
Wed night or Thu, so until then, forcing for upward vertical
motion remains uncertain, but will have to monitor closely
thunderstorm clusters over the eastern Great Lks and northern
Mid-Atlantic as they could track across the area.

Today appears to be the hottest day of this week as westerly
downslope flow results in compressional warming and drying.
Thunderstorm chances this afternoon look almost NIL, however,
guidance indicate a cluster of storms arriving this evening
across northeast Maryland from southeast Pennsylvania. The
timing suggests that convection will be weakening or probably
sub-severe.

Wednesday`s forecast seems to be the most uncertain with respect
to thunderstorm chances. The late Tue night convection will
leave a boundary across the area where it will stall as it
fights the strong ridge to the south. Some thunderstorm
development is possible across central PA and into northern MD.
Timing seems like the biggest uncertainty, but some guidance
suggest an early day complex rolling through the area.

By Thursday, cold front crossing the eastern Great Lks will
likely ignite thunderstorm clusters over much of Pennsylvania
that will likely track further south into the area at some point
during the day or night with potential for severe wx given
strengthening mid-level flow.


KEY MESSAGE 2...Record high minimum temperatures likely this week, but
record high maximum temperatures appear unlikely now.

Guidance has had a high bias the past several days with respect
to daytime highs. In addition, a slight cooling trend has also
been seen which would make any record high maximum temperatures
very unlikely, but the high humidity will keep minimum
temperatures on the very warm side. Some record high minimums
are possible or even likely this week. See Climate section below
for actual numbers.

While it will be hot and humid this week, forecast heat indices
appear will remain shy of heat advisory criteria.


KEY MESSAGE 3...Heat & thunderstorms begin to decrease towards the start of the
weekend.

Beginning on Friday, temperatures decrease back to the lower 90s as
the midweek cold front pushes to the south. Meanwhile, a strong
surface high forming over Quebec will move into New England towards
the start of the weekend. Associated with this will be signficant
dry mid-level air moving across the Mid-Atlantic. As this feature
continues to track south, subsidence across the East Coast combined
with the dry mid-level air will stabilize conditions and reduce
thunderstorm chances going into the weekend. As dewpoints drop,
expect cooler, drier conditions closer to September normals,
especially between Saturday and Sunday as temperatures continue to
drop into the low-to-mid 80s during the day. A few spotty showers
are not completely out of the question as low-level moisture
persists over the mountains during this period, but overall expect
progressively drier and cooler conditions across the Mid-Atlantic
beginning Friday and into the holiday weekend.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
Drying trend noted today, so kept TSRA out of the TAF forecast.
A few evening showers are possible over northeast Maryland
tonight, so added a TEMPO group for BWI and MTN.

Wednesday`s forecast seem pretty uncertain at this time, but
thunderstorm chances seem to increase late Wednesday afternoon
through the end of work week.

Periods of sub-VFR conditions could persist through Friday as
showers and thunderstorms track across the area primarily in the
afternoon & evening hours. Some of these storms could become severe.
Beginning Saturday, thunderstorm potential decreases overall,
bringing conditions to terminals back to primarily VFR through the
weekend. Westerly winds shift northerly on Saturday.

&&

.MARINE...
Winds below 10kt most of the time, but higher winds and waves
can be expected near thunderstorms.

Winds remain below SCA thresholds on Friday before potentially
increasing to marginal SCA conditions on Saturday. Northwest winds
shift northerly early Saturday.

&&

.CLIMATE...
Given slightly cooler trends seen in the guidance for daytime
highs, record high maximum temperatures seem unlikely. However,
record high minimum temperatures are possible.

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/KRR/SRT
AVIATION...LFR/KRR/SRT
MARINE...LFR/KRR/SRT