017
FXUS61 KLWX 020800
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
400 AM EDT Wed Sep 2 2026
.WHAT HAS CHANGED...
Heat Advisories have been issued for the southern half of the
forecast area.
&&
.KEY MESSAGES...
- 1) Daily severe weather threat through the end of the week.
- 2) Hot and humid conditions yield likely record high minimum
temperatures this week.
- 3) Heat & thunderstorms begin to decrease heading into
Labor Day weekend.
&&
.DISCUSSION...
KEY MESSAGE 1...Daily severe weather threat through the end of
the week.
Multiple rounds of thunderstorms, some likely severe with
damaging winds, are likely today through Friday as upper level
disturbances move from the Great Lks into the Mid Atlantic
states. Already seen a small cluster of thunderstorms over south
central Pennsylvania that will move through the area later this
morning. Two additional rounds of thunderstorms seem likely
today, one this afternoon, and a second one late this evening
into the overnight hours tonight into Thursday. Thunderstorms
will ride southeast along and north of a backdoor front
currently pushing south through northern VA and southern MD as
seen on TDWRs and wind shifts to the NE at IAD and DCA a couple
of hours ago. The severe threat will not be necessarily tied to
the afternoon and evening hours as record warm nighttime
temperatures and high humidity yield strong instability and
keep thunderstorms going strong well into the overnight hours.
By Friday, cold front should have cleared much of the forecast
area causing a stabilizing effect limiting the risk of severe
weather, but showers and thunderstorms will still be possible
north of the sfc front.
KEY MESSAGE 2...Hot and humid conditions yield likely record
high minimum temperatures this week.
Decent model agreement that areas south of US-33 and US-211 will
see heat indices meet heat advisory criteria this afternoon.
Based on yesterday`s high temperature readings and greater
confidence, issued Heat Advisories for the southern half of the
fcst area.
Thursday`s max temperature forecast has a lot more
uncertainty due to potential for more convection. If convection
doesn`t materialize, more record high minimums are possible
again today, but that doesn`t seem likely at this time, except
only at Charlottesville.
Record high minimum temperatures were set yesterday at IAD, DCA,
and HGR. RERs were issued earlier.
KEY MESSAGE 3...Heat & thunderstorms begin to decrease heading into
Labor Day weekend.
High pressure tracks southeast from the Great Lakes on Saturday,
pushing a cold front further south of the region. This should
bring a drop in heat & humidity across the Mid-Atlantic, with
afternoon highs ranging in the mid-80s on Saturday. As mid-level dry
air continues to track across the area, temperatures should continue
to decrease as the weekened goes on. By the Labor Day holiday, it
should feel relatively mild & dry, with dewpoints ranging in the
upper-50s across the region.
Thunderstorm chances also begin to decrease past Friday once the
cold front tracks to the south. A few showers & thunderstorms remain
possible along the Blue Ridge as low-level moisture persists
Saturday evening, but overall conditions should gradually clear as
the weekend progresses. Surface high pressure tracks overhead by
Monday, further reducing precipitation chances over the holiday.
&&
.AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
Multiple rounds of thunderstorms are expected today through
Friday. Given low confidence on timing, issued long PROB30
groups for now. Some low cigs are expected at BWI and MTN later
this morning.
Prevailing VFR conditions are anticipated at terminals throughout
the weekend. A couple of thunderstorms remain possible in the
vicinity of KCHO through Saturday afternoon & evening. Light
northwesterly winds shift easterly by Sunday evening.
&&
.MARINE...
Winds 10kt or less outside of thunderstorms. SMWs will likely be
required at some point this afternoon and tonight and again
Thursday.
Wind gusts stay below 15 knots Saturday night and Sunday, with
northerly winds shifting northeast by Sunday.
&&
.CLIMATE...
Record high minimums were set yesterday at IAD, DCA, and HGR.
Please RERs for detail info. More record high minimums are
possible again today, mainly at CHO where convection is less
likely.
Below is a list of record warm temperatures for September 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 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...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
for VAZ025>027-029-036>040-050-051-056-504.
WV...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
for WVZ055-502-506.
MARINE...None.
&&
$$
DISCUSSION...LFR/SRT
AVIATION...LFR/SRT
MARINE...LFR/SRT
NWS LWX Office Area Forecast Discussion