840
FXUS61 KPBZ 151202
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
802 AM EDT Mon Jul 15 2024

.SYNOPSIS...
Periodic showers and storms will be possible through Wednesday as
multiple mesoscale convective systems form upstream. A passing
cold front Wednesday will return near- normal temperatures and dry
weather to the region.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
KEY MESSAGES:

- Convection chances increase later this afternoon.

- Continued well above normal temperatures.
  _________________________________________________________________

Made a few minor updates to the grids based on radar and
satellite trends. The MCS remnants near the IN/OH border have
almost completely decayed at this point. The evolution of the
remnant cloud cover will play a role in how much heating our
forecast area receives into the early afternoon, and therefore
convective chances/intensity. It appears that much of this cloud
cover will fade, allowing for some heating, but trends will need
to be watched. A crossing shortwave along with diurnal heating
should result in at least scattered convection this afternoon
and into early evening. This round of storms may have
sufficient DCAPE to support mainly a damaging wind threat. CSU
machine- learning guidance generally agrees with this. SPC has
maintained the Marginal Risk for the forecast area today.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
KEY MESSAGES:

- Active weather with several convective rounds presenting
  potential severe hazards until the passage of a cold front on
  Wednesday.

- Continued well above normal temperatures.
  _________________________________________________________________

Uncertainty in the forecast continues as upstream development
will largely dictate our weather until the passage of a
Wednesday cold front. Further rounds of convection are expected
but timing is uncertain. Damaging wind will continue to be the
primary threat mode. A more stout shortwave trough dropping into
the Great Lakes on Wednesday will finally help to push a cold
front along for an eventual Wednesday afternoon/night passage,
bringing a more concentrated precipitation area Wednesday, but
then an end to the convective threat behind it.

Heat and humidity will continue to be part of the story during
the early part of the week. The potential for advisory-level
heat index values of 100 or more on Tuesday depending on
convective extent and timing. With 850mb temperatures expected
to reach or exceed 20C over a good portion of the region, a lack
of cloud cover could lead to sufficient sunshine to get surface
temperatures into the mid 90s for some on either day, leading
to the higher heat index values. However, more abundant cloud
cover could keep temperatures below 90 and therefore stunt the
heat impact. Due to this, will hold off on any heat-related
headlines for now, hoping that time and additional near-term
information will lead to increased clarity. More concentrated
clouds and precipitation on Wednesday should limit heating below
advisory thresholds.

&&

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

- A drier and cooler pattern will ensue on Thursday and continue
  into next weekend.

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

The cold front should complete its passage Thursday morning, perhaps
stalling over the Central Appalachians/Middle Ohio Valley, with
expanding high pressure across the Great Lakes and northeast
CONUS into next weekend. Drier weather and cooler temperatures,
perhaps falling a few degrees below normal, can be expected
through Friday night.

The shallow upper troughing in place Thursday and Friday may be
replaced by rising heights Saturday/Sunday in response to increased
troughing over the Central Plains. This could also bring moisture
back from the south, leading to increased diurnal precipitation
chances, mainly southeast of Pittsburgh. A warmup back to seasonable
temperatures can also be anticipated.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
A few isolated showers remain possible through roughly 15Z with
the greatest coverage (and best, albeit low, potential for
thunder) occurring north of I-80. Late morning through afternoon
should be VFR with mostly high clouds and a scattered cu field
with cigs around 4-6kft, followed by low confidence forecast
for additional thunderstorms after 20z along remnant outflow
boundaries from overnight convection. If thunderstorms do
develop, they pose a threat for rapid changes to vsby along
with erratic, gusty winds at any impacted terminals. Another
brief lull is expected after 02z with the departure of any
evening convection, but hi-res guidance suggests another
potential MCS (or its remnants) moving into the area from the
west after 06Z. Outside of convection, expect light south to
southwest winds throughout the period, except during afternoon
hours when they should generally increase to around 10 knots
with gusts to 15-20 knots.


.Outlook...
Periodic shortwave troughs will lend to thunderstorm chances
through mid-week, peaking Tue into Wed with the approach and
passage of a cold front. Timing and coverage will be difficult
to ascertain even a day out due to the strong impact of prior
days` convective evolution.

High pressure is favored by Thu to ensure another period of VFR
and dry weather.

&&

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

&&

$$

SYNOPSIS...88
NEAR TERM...CL/88
SHORT TERM...CL/88
LONG TERM...CL
AVIATION...Cermak/Frazier