Arlington, Virginia 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

021
FXUS61 KLWX 181849
AFDLWX

Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
Issued by National Weather Service Mount Holly NJ
249 PM EDT Mon May 18 2026

.WHAT HAS CHANGED...
Minor adjustments to the thunderstorm chances this afternoon and
evening based on current radar trends, otherwise no major
changes were made to the forecast package.

&&

.KEY MESSAGES...
1) Near record warmth with isolated strong to severe thunderstorms
over the mountains today and Tuesday.

2) A strong cold front brings widespread rain and thunderstorm
chances on Wednesday, followed by much cooler and showery conditions
toward the end of the week.

&&

.DISCUSSION...
KEY MESSAGE 1... Near record warmth with isolated strong to severe
thunderstorms over the mountains today and Tuesday.

It`s a very hot start to the workweek as upper level ridging
strengthens over the region. Aside from areas under the
influence of the bay breeze and higher terrain locations,
widespread 90s have been reported across the region as of 3 PM.
There are a few hours left today for some additional heating,
so no major changes with the forecasted highs. This will mark
one of the hottest days so far this season, although even hotter
conditions can be expected Tuesday as the upper level ridge
peaks over the region.

Scattered showers and storms have already started to develop
over the higher terrain. Storm coverage is expected to be
limited in nature given the lack of a direct lifting mechanism.
Hi-res CAMS show good continuity in regards to convective
development that will be fueled by ample instability, steep low
level lapse rates, and marginal shear. MLCAPE values of
1000-2000 J/kg, DCAPE values of 1000-1300 J/kg, and enough mid-
level flow (20-30 kt) will provide some organization to any cold
pools that develop. This supports forecast soundings with
inverted V profiles indicative of damaging winds which aligns
with several hi - res model members suggesting gusts of 40-50
kts on any storms that form. Any thunderstorm activity will
quickly diminish through the evening hours with dry conditions
and areas of patchy fog. Don`t expect too much relief from the
heat tonight with lows in the upper 60s and low 70s.

Even hotter conditions can be expected Tuesday with highs well into
the low to mid 90s. A few upper 90s cannot be ruled out across the
urban corridor and down to the south across the central VA Piedmont
given the strengthened ridge peaking overhead and dry air at the
surface. An isolated shower or t-storm remains possible over the
mountains, although most will see nothing given the heightened ridge
squashing anything overhead. Temperatures cool slightly Wednesday
with increasing cloud cover as a cold front approaches the region.
Highs will still push into the 90s along with increasing humidity.
Even with that said, the combination of heat and humidity will
remain below heat headline criteria through the period.

KEY MESSAGE 2...A strong cold front brings widespread rain and
thunderstorm chances on Wednesday, followed by much cooler and
showery conditions toward the end of the week.

A strong area of low pressure moves through the Northeast on
Wednesday, with a cold front extending down the East Coast that will
bring widespread rain and thunderstorm chances to the Mid-Atlantic
in the afternoon/evening. While the center low will be well north of
us, the timing of the front aligning with the diurnal cycle and the
high temperatures seen at the start of the week could still
contribute towards some thunderstorm development in the region.
Potential severity at this time still ranges widely--NCAR`s AI NWP
Convective Hazards Forecast currently has our region outlined in its
45%-60% probability for severe weather to occur, while CSU`s medium-
range probabilities ranks the severe threat much lower. Regardless,
this front will likely result in widespread showers at a minimum as
well as a sharp drop in temperatures seen later in the week. Highs
on Thursday will range in the upper 60s and low 70s, a marked shift
from the mid-90s expected earlier in the week. Lingering rain
showers may still be moving out of the area by Thursday morning,
while a meandering front to the south could bring a few additional
rain showers on Friday.

Temperatures begin to increase again going into the weekend, as a
warm front meanders through the region Saturday. Upper-level zonal
flow slow transitions to UL ridging by the end of the weekend,
indicating a potential decrease in rain chances going into the start
of next week.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
VFR conditions are expected to prevail across the terminals
through Wednesday morning as high pressure strengthens offshore.
South/southwesterly winds return today and Tuesday gusting
between 15 to 20 kts during the afternoon and evening hours.
Daily shower and thunderstorm chances will occur each afternoon
although coverage will be spotty in nature mainly at terminals
along and west of a line from KMRB, KHGR, KFDK, to KEKN.
Elsewhere confidence remains low given the lack of a lifting
mechanism and strengthening high pressure overhead.

Sub-VFR restrictions return at times Wednesday afternoon and evening
as a cold front brings widespread showers and thunderstorms to the
region. Winds will remain out of the southwest ahead of the front
before shifting back to the north and northwest Thursday. Some low
CIGS may hang on through Wednesday night before lifting Thursday as
the front sits south of the region. Periodic rain showers moving
through the region on Thursday and Friday could bring additional sub-
VFR periods at terminals towards the end of the week. Wind gusts
could reach 15-20 knots on Thursday before gradually decreasing.
Northerly winds shift east-southeast by Friday night.

&&

.MARINE...
SCA southerly channeling over the bay and lower tidal Potomac
is expected this afternoon and evening. Winds will drop briefly
back below sub-SCA levels tonight before additional SCAs are
needed due to channeling Tuesday afternoon and evening. Winds
will remain out of the south and southwest with gusts up to 20
kts today and Tuesday.

Winds may near low-end SCA levels in south to southwesterly flow on
Wednesday, and then again in northerly flow on Thursday. SMWs appear
possible Wednesday into Wednesday night as thunderstorms move over
the waters.

Small Craft Advisories are likely during the day Thursday & Friday
as winds gust up to 15-20 knots, growing calmer overnight. Winds
drop below SCA thresholds Friday night. Northerly winds shift
easterly by Friday morning.

&&

.CLIMATE...
Here are some daily temperature records during the May 18-20,
2026 timeframe:

A `+` sign indicates multiple years currently hold that record.
A `!` sign indicates the record is forecast to be tied or broken.

                   ***MONDAY, MAY 18TH, 2026***
LOCATION                   RECORD HIGH (YEAR)  RECORD WARM LOW (YEAR)
Washington-National (DCA)        96F (1877)            72F (2015)
Washington-Dulles (IAD)          91F (1987)!           68F (2015)!
Baltimore (BWI)                  97F (1962)            70F (2017)
Baltimore Inner Harbor (DMH)     97F (1962)            75F (2017)
Martinsburg (MRB)                96F (1911)            66F (2015)!
Charlottesville (CHO)            95F (1962)+           73F (1911)
Annapolis (NAK)                  95F (1962)+           69F (1953)+!
Hagerstown (HGR)                 93F (1962)            71F (2017)

                  ***TUESDAY, MAY 19TH, 2026***
LOCATION                   RECORD HIGH (YEAR)  RECORD WARM LOW (YEAR)
Washington-National (DCA)        96F (1997)+           72F (2015)!
Washington-Dulles (IAD)          92F (1997)+!          66F (2017)+!
Baltimore (BWI)                  98F (1962)            75F (1877)
Baltimore Inner Harbor (DMH)     98F (1962)            78F (1962)
Martinsburg (MRB)                98F (1911)            69F (1996)!
Charlottesville (CHO)            97F (1962)            72F (1997)
Annapolis (NAK)                  96F (1962)            71F (1911)!
Hagerstown (HGR)                 97F (1996)            69F (2017)+!

                 ***WEDNESDAY, MAY 20TH, 2026***
LOCATION                   RECORD HIGH (YEAR)  RECORD WARM LOW (YEAR)
Washington-National (DCA)        96F (1996)            73F (2019)
Washington-Dulles (IAD)          93F (1996)            69F (2019)
Baltimore (BWI)                  95F (1962)            71F (2019)+
Baltimore Inner Harbor (DMH)     97F (1962)            74F (1998)+
Martinsburg (MRB)                97F (1911)            70F (1998)
Charlottesville (CHO)            96F (1996)            73F (1996)
Annapolis (NAK)                  98F (1997)            76F (1898)
Hagerstown (HGR)                 97F (1996)            66F (1998)

&&

.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory until 2 AM EDT Tuesday for ANZ531>534-
     537>543.

&&

$$

DISCUSSION...BRO/KJP/EST/SRT/99
AVIATION...BRO/EST/SRT/99
MARINE...EST/SRT/99