813
FXUS61 KPBZ 100553
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
153 AM EDT Mon Jun 10 2024

.SYNOPSIS...
Below average temperatures are expected through early Tuesday
under an upper-level through pattern. Rising temperatures and
dry weather will characterize the mid to late week period. Heat
index vales Thursday and Friday will be well into the 80s.

&&

.NEAR TERM /THROUGH TODAY/...
KEY MESSAGES:

- Cool conditions will persist today under northwest flow.
- A few light showers may develop after 2pm.

--------------------------------------------------------------

Cloud coverage will increase just before dawn from the north as
a new shortwave ejects across the Great Lakes. With spots of
clearing early this morning, temperatures will drop five degrees
below average due to radiational cooling.

Dry, quiet is likely through early afternoon. A few stray
showers may develop downstream of Lake Erie as the shortwave
enters eastern Ohio/western PA. With 850mb temps only ranging
between 5 to 6 degrees Celsius, MaxT temps will struggle to
reach 70F north of I-70.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- Shortwave movement and additional cold front will create low
  probability light rain showers Monday.
- Well below average temperature Monday is expected to become
  near normal by Wednesday as dry weather persists.

-------------------------------------------------------------------

In response to ridge building just west of the upper Mississippi
River Valley, another embedded shortwave will round the New
England trough and cross the region Monday. Isolated light rain
showers may develop along the associated surface cold front, but
weak ascent and moisture origins mainly associated with Lake
Erie should limit activity to the I-80 corridor and (later in
the day) higher terrain. More notably, an uptick in cloud cover
and additional cool advection will keep high temperature 10 to
15 degrees below the daily average while strong radiational
cooling keeps similar temperature transparencies for the
overnight low.

Gradual height rises as the New England trough heads out to sea
and flow out west becomes more zonal will rising temperature
Tuesday into Wednesday. Surface high pressure will cross the
region during this time as well, ensuring plenty of insolation
and dry weather.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
KEY MESSAGES:

- Increasing precipitation chances late Thursday into Friday
  with shortwave movement.
- Upstream convective evolution will play role in timing and
  storm mode during that period.

-------------------------------------------------------------------

The late week period will feature embedded shortwaves within
fairly progressive zonal flow across the north central CONUS
that will shirt towards the Great Lake region late Thursday into
Friday. Ahead of it, confidence if high for above normal
temperature with an uptick in warm, moist surface flow as the
surface high shifts east. With it, the expectation is for an
increased precipitation chances that generally favor northwest
PA.

There remains notable variation in timing/strength of the upper
shortwave, with potential the prior convective evolution near
the western Great Lakes may dictate the quickness of its
eastward progression. Storm timing and strength of the upper
trough will be key in accurately assessing any lightning
potential, but severe weather appears unlikely as the
probability for daytime SBCAPE values to exceed 1000K/kg are
less than 10%.

How quickly the shortwave traverse the area will dictate
weather Saturday, but the general trend is for ridging to
develop over the Ohio River Valley heading into the start of the
next week. There is fairly high confidence in this pattern
which would support dry weather and near to above 90 degree
weather (75% probability of hitting 90+ on Monday 6/17 in
Pittsburgh).

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
VFR will prevail through the overnight with winds 5 knots or
less. Ceiling restrictions will return early Monday as another
weak cold front crosses the area and cold advection in northwest
flow reinforces low level moisture. Latest ensemble
probabilities have trended less aggressive with restrictions
reaching as far south as PIT with about a 30-50% chance there.
Confidence is highest that FKL/DUJ see MVFR CIG restrictions as
probability continues to advertise near an 80% chance. Will
evaluate the incoming guidance overnight, but trends are toward
possibly sparing most sites from MVFR and instead bottoming out
at low-end VFR. Post-frontal cold air will keep low to mid
level clouds in place through much of the afternoon, eventually
scattering from NW to SE by Monday evening with an incoming push
of drier air.

There may be a brief, isolated shower or two up around FKL/DUJ
in the 09Z-15Z timeframe, but confidence in that occurring
remains low and impacts (in addition to the ongoing MVFR CIGs)
would be minimal. Gradient induced northwesterly wind will see
a slight uptick from around 4-7 kts ahead of the front to around
7-10 knots with occasional gusts to 15 kts behind the front.

.Outlook...
VFR conditions are expected under building high pressure Tuesday
through Thursday. Restrictions in showers and thunderstorms return
Thursday night and Friday with another passing disturbance.

&&

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

&&

$$

SYNOPSIS...Hefferan
NEAR TERM...Hefferan
SHORT TERM...Frazier
LONG TERM...Frazier
AVIATION...Rackley/MLB