FXUS61 KPBZ 152348
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
748 PM EDT Wed Apr 15 2026

.WHAT HAS CHANGED...
Updated the aviation discussion for the 00Z TAF issuance.

&&

.KEY MESSAGES...
1) Slight Risk (level 2 of 5) of severe storms today north of
Pittsburgh with much lesser chance farther south. Damaging wind
is the main threat although large hail and a tornado are
possible. Training thunderstorms may pose a localized flooding
threat.

2) Thursday features a Marginal Risk (level 1 of 5) of severe storms
with isolated damaging wind possible. After a break Friday, a
stronger front could bring more severe weather Saturday.

3) Anomalously warm temperatures this week. Daily record high max
and minimum temperatures will be challenged and possibly broken,
especially today.

&&

.DISCUSSION...
KEY MESSAGE 1...
In the wake of early morning convection, scattered cloud coverage
remains with increasing southwest surface flow. Said convection has
left an outflow boundary slowly sagging south past the Pittsburgh
metro as of mid-morning. As southwest flow strengthens into this
afternoon, expect that that boundary likely gets pushed back to the
north while the ambient environment recovers markedly during the
daylight hours. Dew points are not much higher to the south, so
don't expect strong moisture advection today with dew points likely
not moving much from their upper 50s/low 60s this morning. The axis
of highest deep layer moisture content, featuring precipitable water
values of 1.25 to 1.5 inches, will lie north of I-70. This is where
the bulk of the storm activity and severe potential is forecast to
occur this afternoon and evening.

Along with some measure of surface heating into the low 80s, this
should allow surface-based CAPE to easily reach the 1000-1500 J/kg
range according to HREF means. High-end potential, contingent on
more clearing, exists to reach north of 2000 J/kg north of
Pittsburgh, and trends may be pointing in this direction with HREF
cloud coverage in the 50-70% range and actual observations trending
much less. Deep shear will be improved as compared to yesterday,
reaching the 35-40 knot range for 0-6 km values. The highest
confidence storm initiation likely occurs to our west after 3pm
along and ahead of a cluster pushing through the lower Great Lakes
region, perhaps aided by a weak mid-level wave, with activity
spreading east. There could also be initiation along the
aforementioned outflow boundary and other remnant boundaries from
convection yesterday. As convective temperature of 75F is met this
afternoon, that raises a conditional low confidence/higher
severity earlier initiation along the remnant boundaries that
could pose an all hazards risk with brief discrete mode before
quickly growing upscale; better potential for large hail and
perhaps a tornado or two accompanies this north of Pittsburgh
where low-level SRH is maximized, LCLs are a bit lower, and CAPE
in the hail growth zone is more abundant. What may inhibit this
is a persistent warm layer on latest PIT ACARS soundings from
700-800 mb that would need stronger forcing and repeated updraft
attempts to erode. The later storm mode favors quickly
congealing segments/bows as noted by several recent HRRR/RRFS
runs bringing a damaging wind threat. The unchanged SPC day 1
outlook remains in good agreement with the above, leaving a
Slight Risk (level 2 of 5) in place north of I-70 and a Marginal
Risk (1/5) down to about I-70.

With deep layer mean flow nearly due westerly and initiation along
boundaries oriented roughly west-east, training of storms is
possible that could lead to flash flooding. This, again, is most
likely north of Pittsburgh in the high PWAT axis. HREF max 1 hour
QPF reaches north of 1" for a few consecutive hours later tonight
suggesting the threat for training storms dumping inch per hour
rates.

While the severe threat should largely subside by midnight due to
diurnal stabilization, upstream convection could once again impact
the region overnight into Thursday morning, at least in a weakening
state. Such convection is tricky to time and depends at least
partially on leftover boundaries from earlier activity.

KEY MESSAGE 2...
Thunderstorm potential continues on Thursday, as Great Lakes low
pressure drags a weak frontal boundary across the region. Coverage
may be more widespread with some better mid-level forcing just
downstream of a shortwave riding through the Great Lakes, but the
environment it has to work with looks less potent. Although deep
shear will be similar to Wednesday, more widespread cloud cover may
hinder the buildup of instability. Poor low-level curvature to
hodographs with uniform column southwest flow and poor mid-level
lapse rates point to lower tornado and hail potential leaving
isolated damaging wind as the most likely impact from the stronger
storms. The SPC day 2 Marginal Risk (level 1 of 5) area was expanded
to cover most of the forecast area north and west of Morgantown.

A southern stream shortwave dipping into the Tennessee Valley will
finally dislodge the southeast CONUS ridge Thursday night as the
afternoon and evening showers and storms work their way out after
sunset. We should get a break from the daily convective cycle as
brief shortwave ridging traverses overhead. It'll be short lived
though before one last round of strong to severe storms will arrive
with a stronger cold front Saturday afternoon/evening. While details
remain fuzzy, this feature should provide the strongest lift we've
seen in the past week, so favorable timing would point toward a
heightened severe threat. Timing of the front is still uncertain and
dependent on tilt and progression of the mid-level wave with AI
models suggesting late afternoon and some ensemble clusters as late
as after sunset.

KEY MESSAGE 3...
An anomalously strong (500mb heights at the 99th percentile) and
stubborn ridge remains centered over Florida and extending across
the southeast CONUS into Thursday before being weakened some by
upstream shortwave activity. It still appears that today will
feature the best chances of record-breaking temperatures. Warm
and moist southwest flow today will push 850mb temperatures into
the 14 to 16C range, which, assuming good mixing and lesser
cloud coverage, would top out MaxTs in the low 80s. Such
temperatures are most likely south of Pittsburgh away from the
ridges while areas to the north feature more cloud cover and
better precipitation chances.

This is reflected in NBM temperature record probabilities for today.
Sites PHD (shorter climate record), HLG, and MGW all have 85% or
greater probability of reaching record highs today according to
statistical guidance. Probabilities for ZZV and PIT are lower
(~50%). There are also decent probabilities both today and
Thursday for record warm minimum temperatures, with PIT, PHD,
and HLG featuring 70% or greater chance of setting such
standards both days.

Thursday remains warm, with 60% or greater probability of
temperatures of 80 or higher south of I-80, but this may be a
bit overdone with higher probability for more areawide cloud
cover and showers and storms which may hinder the potential of
record highs (probabilities drop below 30% areawide). The next
best shot for these may be Saturday, with perhaps some sun and
southwest flow ahead of an approaching front, but timing of the
front will dictate how high temperatures get. The warmth
definitively ends by Sunday behind this boundary.

Minor heat risk continues areawide today and Thursday before
retracting some on Friday. Heat impacts will primarily be felt
by those who are extremely sensitive to heat and those without
cooling/hydration, but will be notable to all with this being
the first warm up of the year. Speckled moderate risk areas are
indicated today and Thursday especially, mainly in the Ohio and
Mon river valleys.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
The primary round of thunderstorms, some of which are strong to
severe, is moving through the area north of PIT to start the 00Z
TAF period. This wave of convection should move out of the area
to the east by the 03Z-06Z timeframe, after which only a few
isolated lingering showers will be possible (still primarily
north of PIT). VFR conditions prevail outside of convection.

After a lull in activity overnight (aside from a few isolated
showers and storms possible towards sunrise at FKL), another
line of convection is forecast to move through the area along a
cold front in the 18Z-00Z timeframe Thursday. A wind shift to
westerly will occur behind that line of convection with gusts to
around 25 knots continuing.

Outlook...
Friday should be mostly dry following Thursday evening's weak
frontal passage. However, another low pressure system and a
stronger cold front approach the area on Saturday, returning
shower and thunderstorm chances (and associated restrictions) to
the region through the weekend. Dry weather and VFR conditions
are then favored as we head into early next week with a pattern
shift following the weekend cold front.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.

&&

$$

DISCUSSION...MLB/CL
AVIATION...Cermak