132
FXUS61 KLWX 141433 AAA
AFDLWX

Area Forecast Discussion...UPDATED
National Weather Service Baltimore MD/Washington DC
1033 AM EDT Tue Jul 14 2026

.WHAT HAS CHANGED...
Adjusted MaxT for today and dewpoints today through Fri. Still
looking at likelihood of issuing Heat Advisories for most of the
area later today for Wed.

&&

.KEY MESSAGES...
1) Heat Advisories appear likely for Wed and possibly Thu.

2) Uncertainty remains with how long the high heat persists and
potential for severe t-storms Fri into the weekend.

&&

.DISCUSSION...
KEY MESSAGE 1...Heat Advisories appear likely for Wed and
possibly Thu.

12Z upper air plots show that the center of the 500 mb high is
located over LK Michigan or southern Wisconsin with Minneapolis
measuring 6000-meter 500 mb heights and an 850 mb temperature
of 25C. This hot air mass will advect east southeastward next
two days with 850 mb temps peaking around 23-24C here, which is
slightly hotter than what we experienced here earlier this
month. Most guidance have sfc dewpoints in the mid to upper 60s
on a westerly flow. So, a 100F air temperature combined with a
dewpoint of 67 yields a heat index of 105.5F. Looking like we`ll
be issuing a Heat Advisory for most of the area for tomorrow.
Also, haze due to smoke from large wildfires in western Ontario
is seen on GeoColor imagery advecting southwestard around the
periphery of the upper high. This is already arriving in
northern MD and will only get worse over the next two days as
the subsidence inversion strengthens. So, expect deteriorating
air quality conditions as well.

KEY MESSAGE 2...Forecast confidence decreases substantially
late this week into the upcoming weekend, but the potential is
there for both extreme heat and severe thunderstorms.

Not too much of a change in the overall synoptic pattern as lw
trofing dominates. This sets up a NW flow pattern given the
trough in the Pacific NW and Interior Northeast along with the
broadened ridge over the central U.S. As a result, there remains
considerable discrepancies amongst long range model guidance in
regards to the timing of sw disturbances which lower confidence
in regards to temps and the potential for severe t-storms
heading into the weekend period. Ensemble guidance has members
showing highs anywhere from the upper 70s to the mid 100s each
day Fri through Sun, with above average spread on Thu as well
(mid 80s to mid 100s). So depending on which solution verifies,
we could have anywhere from well below normal temps to record
highs each day. That, in turn, will have impacts on severe
t-storm potential each day.

Right now, the highest chances for t-storms (some severe)
appears to be this weekend as a more potent shortwave drops
south from the Great Lakes within NW flow. Some spread still
remains amongst 18z/00z guidance in respect to where this system
will track and where the associated cold frontal boundary ends
up as it pushes through the region. Most model solutions have
substantial height falls during this period which should lead to
higher t-storm coverage Sat and potentially Sun as well. As for
Thu and Fri, the risk for t-storms and severe wx is lower, but
not zero. SW disturbances should pass to the north given a W to
NW flow pattern aloft and at the surface. This will lead to
downsloping east of the mtns which will keep convection isolated
a relegated to either the terrain or bay/river breeze.

Any storms that we do see will likely be strong to severe given
the hot and humid airmass in place. Damaging wind gusts in
excess of 60 mph and isolated lager hail cannot be ruled out.
This aligns with current SPC Day 4-8 outlooks and CSU/NSSL/CIPS
suggest a 5 to 20 percent probs of severe wx during the weekend
period. Uncertainty continues beyond Sun given the placement of
the front. Some pieces of guidance have the front bisecting the
region Sun into Mon while others force it south of the region.
There are also some indication of an area of low pressure that
look to form along the boundary Mon as it pushes offshore. This
will be something to monitor leading to lingering chances for
showers and t-storms along with potential severe wx during the
back half of the extended period.

&&

.AVIATION /14Z TUESDAY THROUGH SATURDAY/...
VFR conditions through Thursday. However, haze due to smoke is
seen moving southwestward from Pennsylvania into northern
Maryland at this time on GeoColor imagery around the periphery
of the upper high centered over Lake Michigan. This haze
combined with a strengthening subsidence inversion associated
with the upper ridge may result in MVFR VSBYs today through
Thu.

VFR through Thu into upcoming weekend. SHRA or TSRA possible
each afternoon and evening with the greatest opportunity for
restrictions this weekend. Winds will remain light out of the
west and northwest with speeds less than 15 kts.

&&

.MARINE...
S`ly channeling could result in SCA gusts this
afternoon/evening, but given short duration/threshold nature
leaning MWS.

Sub-SCA level nw`ly winds are expected Thu and Fri. SMWs may
be needed on Thu or Fri if t-storms move over the waters. More
widespread t-storm activity and the need for SMWS will be needed
over the weekend as a cold front sags into the region. S`ly
channeling also returns to portions of the waters Sat into Sun.

&&

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

&&

$$

DISCUSSION...LFR/CPB/EST
AVIATION...LFR/CPB/EST
MARINE...LFR/CPB/EST

NWS LWX Office Area Forecast Discussion