PBZ issues Area Forecast Discussion (AFD) at Mar 14, 7:12 PM EDT027
FXUS61 KPBZ 142312
AFDPBZ
Area Forecast Discussion
National Weather Service Pittsburgh PA
712 PM EDT Fri Mar 14 2025
.SYNOPSIS...
Dry and unseasonably warm conditions prevail through tonight.
Rain returns this weekend with the threat of severe weather on
Saturday and Sunday. A brief cooldown is favored to begin next
week with returning dry weather.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
KEY MESSAGES:
- Dry with increasing clouds and wind tonight.
-------------------------------------------------------------------
Evening Update: No changes were needed for the overnight period.
Plentiful sunshine this afternoon and a warm front slowly
lifting back to the north allowed daily high temperature records
to fall or be tied at 5 of 6 regional climate sites. MGW's high
of 80F tied for 5th earliest 80F day on record.
Cirrus coverage will increase tonight as upper level moisture
streams in. Increasing southerly flow with a tightening gradient
will promote warm, moist advection overnight and low
temperatures 20+ degrees above normal.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
KEY MESSAGES:
- Dynamic system will bring potential for wind, flooding, and severe
both days this weekend but now favoring Sunday.
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Lingering ridging will deflect an upper low ejecting out of the
central Plains through MN/WI on Saturday. The surface low will
follow a similar track dragging with it our previously stalled
boundary back north once again as a warm front. This will be a
dynamic system bringing a mixed bag of hazards. Winds begin to
pick up Saturday morning as the surface pressure gradient
tightens and elevated 850 mb flow overspreads; NBM 24hr max
gust probabilities suggest widespread 40 mph gusts in the
lowlands (40-70%) with probabilities north of 90% in the
ridges. By Sunday 40 mph probabilities are as high as 70-80% in
the lowlands and advisory criteria (46mph) is greater than 95%
in eastern Tucker County. A wind advisory is highly likely
within the next 12-24 hours.
In terms of severe weather... there's been a shift in the day with
the highest threat from Saturday to Sunday. Latest runs of the CAMs
continue to look less and less threatening with the threat on
Saturday. A decaying convective complex limping through
central/eastern OH overnight Friday night into Saturday morning is
going to outrun its marginally favorable environment given
unfavorable diurnal timing and weak forcing. Thick cloud coverage
both from warm advection and convective debris across most of the
area Saturday morning is highly likely to suppress destabilization
headed into the remainder of the day; even the NBM 10th percentile
cloud coverage suggests minimal scattering into the afternoon hours.
Directional and speed shear will be more than sufficient, but lack
of strong forcing to overcome minimal instability will largely
squash severe chances. The best buoyancy plume is progged to be off
to our west across central and western Ohio where more breaks in the
clouds are expected and there's more recovery time after the morning
convection. HREF probs for >300 J/kg with 40-50 knots of deep layer
shear sneak to around 50% only as far east as a Canton to Zanesville
line. That said, some lingering boundaries from the earlier batch
may be able to spark off some afternoon redevelopment locally,
but confidence is low overall, and even if it does, it won't
have much of an environment to work with. In coordination with
SPC, have removed the Slight Risk from our area and now are left
with a Marginal Risk (1/5).
A new surface low develops late Saturday in the central Ohio
River Valley and progress northeast overnight. This will drag
potentially two rounds of showers and storms across the area:
one in the morning along a narrow trough axis and another in the
late afternoon with a cold front. With both of these features,
severe weather is possible. Strong dynamics remain in place with
an even more potent wind field aloft, especially in the morning
hours. A potent 50-60 kt LLJ will move through in the morning
accompanying the first round of convection. There's some
uncertainty if this round will be fully surface-based with
timing being not long after sunrise into eastern Ohio. If it is,
forecast soundings exhibit a large, looped hodograph in the
lowest 0-2 km with sufficient 0-3 km CAPE to support strong low
level stretching and 0-3 km shear in excess of 50 knots. This
suggests messy storm organization in the mid and upper levels,
but of concern will be a damaging wind and embedded tornado
threat, which may not even be contingent on an exact line-normal
orientation given the magnitude of the shear vector. The hail
threat looks low given weak mid-level lapse rates and a skinny
CAPE profile. The same threats will arise again later in the
afternoon when the cold front moves through. CAMs are rather
insistent on additional development along it despite a lower
March sun angle having just a few hours to work with in the wake
of the morning batch. Stronger lift along the front may help
wash out the effects of lesser instability. The notable
differences in profiles will be higher dew points --> lower LCLs
and a slightly weaker wind field overall. The Marginal Risk
(1/5) has been expanded areawide on Sunday.
Heavy rain remains a concern with the potential flood threat highest
in eastern Ohio. Deep southerly flow will help PWATs surge north of
1 inch (near the climatological 99th percentile). Convective
enhancement tied into this could raise the concern for localized
flooding and will continue to monitor this threat with upcoming hi
res ensemble runs.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
KEY MESSAGES:
- Dry early week period with gradually moderating temperatures.
- Rain returns by mid-week.
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The end of our unseasonably warm period will arrive on Monday in the
wake of Sunday's cold front. As the upper trough digs overhead,
colder air will filter in and return highs closer to seasonal
normals in the upper 40s. Ensemble clusters suggest a weak trailing
shortwave swinging through the trough axis early Monday with some
lingering low level moisture to work with which could support
some lingering showers or even some wet snowflakes mixing in,
especially in the ridges.
All clusters indicate eastward translation of the wave packet later
Monday into Tuesday but, just how far is a much muddier picture. The
slowest solution dominated by the GEPS still has the trough
lagging across the region suggesting overnight lows as low as
the 20s while the most optimistic clusters have already
introduced ridging from the Midwest and holding lows some 10
degrees warmer. The same can be said headed into Tuesday with
the colder solution suggesting low 50s with a warmer solution in
the low 60s, but on Wednesday a warmup looks increasingly
likely areawide. So, while temperatures remain uncertain, what
is certain is that surface high pressure maintains dry weather
through most of the day on Wednesday.
At that point, an upper trough digs across the Midwest with a host
of uncertainty in its timing and the strength of the overhead
ridging. Low pressure will move through the Great Lakes and drag a
cold front through the area sometime Wednesday night into Thursday.
A quicker, less likely, solution suggests rain arriving as early as
Wednesday evening while the majority indicate a stronger signal for
later arrival overnight.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions continue through the forecast period, with
predominantly southeasterly winds occasionally gusting into the
mid teens during the afternoon as stronger winds aloft mix down
to the sfc. LLWS will be possible tonight after sfc winds
decouple and winds aloft increase.
Winds will pick with gusts between 20kts and 30kts during the
day on Saturday, with increasing rain and storm chances (some
possibly severe), as a warm front lifts north over the area.
Outlook... Rain and storm chances (some severe) continue Sunday
with winds veering first to the southwest, then northwesterly
with the passage of a cold front.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...None.
WV...None.
&&
$$
SYNOPSIS...MLB
NEAR TERM...Rackley/MLB
SHORT TERM...MLB
LONG TERM...MLB
AVIATION...88
Source:
PBZ issues Area Forecast Discussion (AFD) at Mar 14, 7:12 PM EDT---------------
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