305
FXUS61 KLWX 021828
AFDLWX
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
228 PM EDT Wed Sep 2 2026
.WHAT HAS CHANGED...
A Severe Thunderstorm Watch is in effect until 5pm for Maryland
from Allegany County to Cecil County to St. Mary`s County and
for eastern portions of West Virginia and much of northeastern
and central Virginia. Within the next hour, we may be canceling
the northern half of our watch as convection has weakened and
moved out to the south.
&&
.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.
The original Mesoscale Convective Complex that moved out of
Pennsylvania into our CWA late this morning has now bowed well
south and east out over the Delmarva and central Chesapeake
Bay and is aligned to the west and northwest into northeastern
Virginia and northwest into eastern West Virginia. Winds have
gusted between 45 to 65 mph within this complex, while isolated
supercell thunderstorms that have become severe from Hampshire
County to Fauquier County are producing large hail with damaging
winds. Round two of thunderstorm clusters could develop
somewhere over western or northwest Pennsylvania later this
afternoon before racing east and southeast again toward our
area. Confidence in timing and initiation of such thunderstorms
are uncertain. We almost need to wait until storms start
developing then we can track it and time better. This particular
setup of transferring from Round 1 to Round 2 may be similar
should be get Round 3 or 4 overnight tonight through Thursday
night. By Friday, cold front should clear 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. Timing seems to slow with later model
runs of this outcome.
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 through region throughout the day. Some
uncertainty still exists regarding how far south this front
will advance south before stalling, but most ensemble members
depict this boundary south of our region by Saturday afternoon.
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.
&&
.AVIATION /18Z WEDNESDAY THROUGH MONDAY/...
Multiple rounds of thunderstorms this afternoon through Friday.
Given low confidence on timing, issued PROB30 groups for now. As
thunderstorms develop and show signs of motion, then we can go
to Tempo groups or certain from groups.
This weekend, prevailing VFR conditions are expected across all
terminals. A few showers and thunderstorms Saturday afternoon &
evening could reduce flight categories briefly near the KCHO
terminal. Light northwesterly winds on Saturday shift to
easterly and calm by Sunday evening.
&&
.MARINE...
Winds 10kt or less outside of thunderstorms. SMWs likely through
the early evening and then again overnight into Thursday again.
On Friday and Saturday, winds below 15kts most of the time, but
higher winds and waves could during afternoon and evening showers or
thunderstorms. light northwesterly winds shift easterly by Saturday
afternoon.
&&
.CLIMATE...
Record high minimums were set yesterday at IAD, DCA, and HGR.
Please RERs for detail info. More record high minimums are
possible again tonight and Thursday night.
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 until 8 PM EDT this evening for VAZ025>027-029-
036>040-050-051-056-504.
WV...Heat Advisory until 8 PM EDT this evening for WVZ055-502-506.
MARINE...None.
&&
$$
DISCUSSION...LFR/KLW/SRT/KVH
AVIATION...LFR/KLW/SRT/KVH
MARINE...LFR/KLW/SRT/KVH
NWS LWX Office Area Forecast Discussion