120
FXUS61 KPBZ 010137 AAD
AFDPBZ

Area Forecast Discussion...UPDATED
National Weather Service Pittsburgh PA
937 PM EDT Sun Jun 30 2024

.SYNOPSIS...
Building high pressure will return comfortable dry weather for
the first half of the week before an unsettled pattern takes
hold to close out the week.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
KEY MESSAGES:

- Cooler and drier weather expected tonight behind an exiting
  cold front
-------------------------------------------------------------------

Update...
Stratocu will continue to overspread the region early tonight
with a crossing upper trough and cold advection. Model soundings
indicate some decrease in the cloud cover is expected overnight
as dry advection occurs in the low levels.

Previous discussion...
We then finally get a push of drier air (dew points in the 40s
upstream) as high pressure builds across the Great Lakes and
reinforces northerly flow in the wake of the boundary. Clouds
will scatter into early this evening save for north of I-80
where forecast soundings indicate that lake moisture under
northerly flow will remain trapped beneath increasing
subsidence. In addition, a passing upper wave looks to reinforce
cloud coverage further south toward morning on Monday. Still,
overnight lows will be refreshing dipping into the 50s (even
60-80% chance of upper 40s in the ridges and north of I-80).

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH TUESDAY NIGHT/...
KEY MESSAGES:

- Dry and comfortable start to the workweek.
- Temperatures below normal Monday and back toward normal Tuesday.
-------------------------------------------------------------------

Dry weather continues with high confidence through Tuesday as good
agreement amongst the various ensemble clusters supports rising
heights as ECONUS ridging builds. High pressure migrates further
east and slides overhead by Monday night. Continued dry northerly
flow will provide a very comfortable, mostly cloud free day on
Monday. Temperatures remain below average with ensemble probability
<20% of highs topping 80 degrees. Dew points only on either side of
50 will be a nice relief from the mugginess of the past few days.

Temperatures begin to rebound on Tuesday by nearly 5-10 degrees
compared to Monday. Flow becomes more south of east and pushes highs
back toward or a couple degrees above normal with 850 mb
temperatures increasing to 14-16C. The day may also feature a bit
more cloud cover, especially later in the day, as upper level
moisture increases. Monday and Tuesday will be the picks of the week
as a more unsettled pattern takes hold for the latter half.

&&

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

- Showers and thunderstorms possible Wednesday continuing through
  the end of the work week with the return of a more active
  pattern.
-------------------------------------------------------------------

By mid-week, ensembles break the ridge down and shunt it southward
over the Southeast CONUS and Gulf Coast, leaving zonal flow over the
Ohio Valley and lower Great Lakes while lower heights settle in
upstream over the upper Great Lakes and Midwest. This patten is
certainly more active than the first half of the week, promoting
surface low pressure over southern Ontario that quickly tracks
northeastward and leaves a trailing cold front sagging southward
into our area late Wednesday into Thursday. There is some minor
concern at this time that the zonal flow overtop what appears to be
a slowing and weakening/diffusing cold front could lead to a setup
where multiple rounds of showers and storms develop along said east-
west oriented boundary in a moisture-rich environment (ensemble mean
PWATs surpassing 1.75 inches), leading to training of thunderstorms
and flooding rain potential. Still a bit too far out to dive into
certain specifics, but will have to keep an eye on the pattern
evolution and potential for an unsettled July 4th holiday. Machine
learning continues to highlight some severe potential with this
pattern as well as the front will initially be moving into a warm
and moist airmass, though weak flow aloft resulting in limited bulk
shear is helping to keep the overall threat low at this time. Still,
this too will bare watching over coming days.

Ensembles then signal an upper wave diving through the Great
Lakes to close out the week, though uncertainty comes into play
with how deep the trough is and subsequently how strong the
surface low is and where it tracks. Consensus is to our north
and dragging a cold front through sometime early in the weekend,
but details remain fuzzy.

&&

.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Stratocu cigs 3-5 kft are evident DUJ-BVI-10G and making sewd
progress this evening amid gusty nnwly wind. As sfc high
pressure builds into the region later tonight, wind is expected
to slacken.

Subsidence should begin to erode the stratocu from the west,
leading to eventual decrease of cloud coverage but not before it
translates into the DUJ/PIT/AGC/LBE area overnight for at least
a few hours. TAFs were updated to reflect MVFR cigs arriving at
all terminals and persisting for at least a few hours before
subsidence asserts itself.

There is high confidence that any cigs will erode and become
scattered by Mon morning, with a sunny day, lighter nnely wind
and mainly high clouds at all terminals on tap.

.Outlook...
VFR is expected until a slow moving front sets up across the
region Wed and Thu.

&&

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

&&

$$

SYNOPSIS...MLB
NEAR TERM...WM/MLB
SHORT TERM...MLB
LONG TERM...Cermak/MLB
AVIATION...Kramar/Hefferan