602
FXUS61 KPBZ 151213
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
813 AM EDT Sat Jun 15 2024

.SYNOPSIS...
A large ridge will build over the region Sunday and remain in
place through the rest of the week. A prolonged and potential
dangerous heat wave is anticipated under this ridge.

&&

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

- Dry weather and comfortable conditions today.
-------------------------------------------------------------------

8am Update: No major changes have been made to this forecast
period.

Previous Discussion:

Heights will slowly rise today as the large developing ridge to
our west pushes the New England trough out over the Atlantic.
High pressure moving across the Great Lakes and will bring an
additional push of drier air as well as keep our low-level flow
out of the north. This will mean plenty of sunshine and
comfortable conditions.

&&

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

- Dry weather, noticeably warmer Sunday.
- Heat really begins to take hold on Monday.
-------------------------------------------------------------------

Axis of upper level ridge will settle in over the region on
Sunday as it amplifies. Flow will veer to the south and strong
warm air advection will ensue. Plenty of sunshine under strong
subsidence and temperatures in the mid 80s to lower 90s are
expected.

Ridge remains centered over the region Monday and continues to
amplify. Strong warm air advection will push temperatures well
into the 90s on Monday. Records at some, if not all, climate
sites will be in reach.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
KEY MESSAGES:

- High confidence in a dangerous heat wave setting up next week
  with major heat impacts possible.
-------------------------------------------------------------------

Guidance has been consistent that a potentially-historic ridge will
continue to strengthen across much of the central and eastern CONUS
into the middle to later part of next week. WPC ensemble
clusters are highly consistent through at least Wednesday and
possibly Thursday, indicating high confidence in the
temperature forecast. Near-record breaking heat will hold
through most of the week.

Significant heat is looking increasingly likely with this
anomalously strong ridge with major to extreme heat risk
likely. NBM probabilities for high temperatures reaching 95+
degrees remain high, and are now widespread 60-90% across the
area. These higher probabilities are especially prevalent in
lower elevation areas (e.g., river valleys) and urban centers,
which tend to be warmer than surrounding areas. In addition,
dewpoints are currently forecast to remain in the mid 60s to
lower 70s, which would result in high enough humidity levels to
support heat indices climbing to, and potentially exceeding, 100
degrees. If dew points do hold toward the lower end of that
spectrum, we may be able to make a run at 100 degree air
temperatures Tuesday and beyond (last time at PIT was 7/15/95);
NBM probabilities for that threshold have leveled off somewhat
and are are now generally 50 to 60% through Thursday with a
focus on the low lying and urban areas. Only acting to
exacerbate the prolonged heat effects will be a 60-80% chance of
low temperatures greater than 70 degrees through the end of the
week. Additionally, with the ridge mainly centered over the
region, very strong subsidence should keep skies mainly cloud
free. Also, the position of the ridge would suppress any threat
of convection. Heat impacts will need to be closely monitored
and headlines will need to be considered.

Impacts include heightened heat-related illnesses and potential
power grid issues with increased demand. It is strongly
encouraged to know where cooling shelters are located and stay
hydrated. There may be little relief at night. Gather food,
water and medication now. Make a list of friends and family to
check on and help them prepare. Strongly consider rescheduling
outdoor events. Prolonged exposure to excessive heat was the
primary cause of weather-related fatalities in 2023.

&&

.AVIATION /12Z SATURDAY THROUGH WEDNESDAY/...

VFR conditions, dry weather, and light winds from the north are
likely for the remainder of the TAF period under high pressure.

Winds will shift from south Sunday evening.

.Outlook...
High probability for VFR and dry weather through the middle of
next week as strong ridging develops aloft.

The only variancemay come with isolated afternoon convection
starting Monday, but upper ridging should suppress coverage and
potential initiation.

&&

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

&&

$$

SYNOPSIS...22
NEAR TERM...22
SHORT TERM...22
LONG TERM...22/MLB/Milcarek
AVIATION...Hefferan