877
FXUS61 KPBZ 071817
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
217 PM EDT Fri Jun 7 2024

.SYNOPSIS...
Isolated to scattered showers are expected early this afternoon
and again Sunday with weak upper level disturbances. Otherwise,
dry weather is expected with temperature fluctuating between
near and below normal.

&&

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

- Dissipating isolated shower activity expected tonight.

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

Isolated showers traversing northwest PA in association with weak
shortwave movement aloft will dissipate in occurrence during the
late afternoon and evening hours as peak heating is lost. The
storm environment remains muted given a staunch 700mb inversion
that will cap storm heights generally below the ice growth
layer (below -10 degrees C) and limit lightning/severe weather
production. That said, deep mixing of the below 700mb layer
will maintain occasional gusts up to 30 mph before diurnal
heating/mixing subside tonight.

High pressure and dry advection aloft will support clearing
overnight skies and foster strong radiational cooling. Area
temperature will fall a few degrees below the seasonal average
as a result.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
KEY MESSAGES:

- Dry weather with near normal temperature is expected Saturday.
- Low QPF showers are likely with crossing cold front Sunday.

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

Weak height rises ahead of the next shortwave trough within the
broader Great Lakes troughing will support more seasonable
temperature Sunday with plenty of insolation. Increasing cloud
coverage overnight amid moist advection aloft will buoy
overnight temperature.

The aforementioned shortwave will traverse the region Sunday
while pushing a weak cold front through the day. Precipitation
chances peak ahead of the boundary Sunday morning; this timing
should keep instability generation minimal and thus
lightning/severe probabilities low. The lack of strong column
moistening and weak overall ascent should keep QPF totals low as
most of the region has less than 20% probability of exceeding
0.25". Northwest PA and its closer proximity to upper jet stands
the best chance for seeing slightly higher amounts, but
probabilities of exceeding 0.5" are only 10%.

Shower activity will become more isolated through the afternoon
as the shortwave exits as dry advection commences in its wake.
Clearing overnight skies and cold advection effects will be
muted by elevated wind, resulting seasonable low temperature.

&&

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

- Persistent upper troughing will support below seasonable
  temperature and low probability rain chances Monday.
- Temperature moderation likely through the weak under
  influence of high pressure.

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

Additional shortwave movement within Great Lakes troughing will
reinforce the seasonably cool temperature Monday while
generating low probability / isolated afternoon showers favoring
northwest PA and the higher terrain. Clearing skies plus high
pressure Monday night will create the coolest temperature of the
weak, as lows Tuesday morning approach 10 degrees below average.

Ensembles favor gradual height rises through much of the work
week as surface high pressure centers along the Atlantic Coast.
Expect a continuation of dry weather and temperature rising near
to above seasonable averages through Thursday.

Variation remains high on the late-week period, with models
diverging into ridging versus troughing solutions. A ridging
outcome would translate to above normal temperature and low
probability afternoon thunderstorms while troughing would
translate to falling temperature and more widespread convection
along a passing cold front.

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
As expected, a broken cu field with VFR cigs has developed
across the entire area thanks to convective temperatures being
reached via daytime heating/mixing. Isolated to scattered
showers have also continued generally along and north of I-80,
with only minor impacts primarily limited to FKL/DUJ. Westerly
winds have become breezy and are sustained at 10-15 knots with
frequent gusts up to 25 knots being observed at most terminals
as of the 17Z obs. Expect these ongoing conditions to continue
through the remainder of the afternoon, though the coverage of
showers north of I-80 should gradually taper as drier boundary
layer air begins to make its way into the area limiting
moisture and instability. The cu field dissipates and winds
settle after sunset with the loss of daytime heating and mixing.

Light winds and VFR conditions then prevail overnight into
Saturday as weak high pressure briefly builds into the area.
Winds could start gusting 15-20 knots again with the onset of
daytime heating/mixing after 15Z Saturday, but overall winds
should be weaker and gusts less frequent than today.

.Outlook...
Scattered showers and associated restrictions return Saturday
night through Monday as another disturbance moves through the
Great Lakes region. High pressure brings widespread VFR back to
the area Tuesday.

&&

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

&&

$$

SYNOPSIS...Frazier
NEAR TERM...Frazier
SHORT TERM...Frazier
LONG TERM...Frazier
AVIATION...Cermak