643
FXUS61 KPBZ 032359
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
759 PM EDT Thu Apr 3 2025

.SYNOPSIS...
An active pattern continues into the weekend with multiple
rounds of showers and thunderstorms. Isolated severe storms are
possible this evening, mainly south of Pittsburgh. Severe storms
will also be possible Saturday.

&&

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

- Flood Watch remains in effect for portions of eastern Ohio.
- Another round of showers and storms returns late this
  afternoon into the overnight.
- An isolated severe storm or two is possible south of I-70.
-------------------------------------------------------------------

Showers have mainly shifted south of the forecast area this
afternoon as the frontal boundary slowly shifts southward into
central WV. However, a line of light showers has formed along
the cold front that is currently crossing the region from east
to west. Rain from this is expected to remain brief and light,
and stay mainly south of Pittsburgh.

Another shortwave will cross the region late this afternoon as a
deeper plume of moisture rides up from the southwest. Showers
and thunderstorms are expected to overspread the area through
the evening hours in response. An isolated, conditional severe
threat is expected through the evening hours south of I-70. At
this time, best severe potential appears to be south of our area
along the front into central WV. While shear will be very
favorable, lapse rates will be poor and instability meager.
Still, if a deeper thunderstorm does develop, all hazards will
be possible.

Heavy rain is expected through the overnight, especially south
of the Mason-Dixon. HREF mean shows around an inch of QPF
through the overnight for northern West Virginia. Better
rainfall coverage diminish and likely shift to the south again
after 06z, with some clearing across eastern OH and western PA
in the early morning hours. Morning lows will fall into the 40s
and 50s.

&&

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

- Rounds of showers and thunderstorms continue into the weekend.
- A Flood Watch remains in effect for portions of eastern Ohio.
- A couple rounds of severe weather are possible on Saturday.
-------------------------------------------------------------------

The surface front will remain stalled south of the area on
Friday, with primary focus of showers south of the Mason-Dixon
through the day. Areas north of I-70 will have a period of dry
weather from mid-morning through much of the afternoon. Yet
another surface low is then expected to track NE out of the
Mississippi Valley region Friday night, pushing the front back
north this time as a warm front. Showers and thunderstorms once
again increase in coverage as the front and surface low move
across the Upper Ohio Valley region into early Saturday.
However, if the front moves far enough north, we may see a break
in the activity late Friday night and Saturday morning as the
main moisture plume will be forced northward as well.

Another round of thunderstorms is possible late Friday into
early Saturday morning as the warm front lifts across the area.
A second round of thunderstorms is then expected Saturday
afternoon/evening ahead of a crossing cold front. CAMs are
hinting at severe weather potential with this round of possibly
discrete storms, and modeled hodographs suggest at least
marginal tornado threat.

Showers and thunderstorms will continue into Saturday night as
low pressure crosses, but the stalled front remains. Flooding
potential will increase on Saturday with repeated rounds of
heavy rainfall on an already saturated ground. Rises are
expected on area rivers.

&&

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

- A cold front on Sunday will finally bring an end to the heavy
  rainfall threat.
- Colder next week with lighter rain/snow chances each day.
-------------------------------------------------------------------

Ensemble clusters agree on a deep upper trough swinging across
the eastern CONUS on Sunday into Monday. This will finally
shunt the surface ridge that had been firmly planted over the
southeast CONUS coast and allow a cold front to advance through
the area and off to the east by Monday, bringing an end to the
heavy rain and storm potential. Weak surface low pressure
crossing out of the Great Lakes will aid strong northwesterly
flow behind the front Monday night into Tuesday. This could
bring a additional few showers to the region on Tuesday.

Upper troughing is expected to persist through midweek,
resulting in below normal temperatures and daily rain/snow
chances, albeit not nearly as intense as what we`re experiencing
this week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
VFR cloud decks are observed across a majority of the region at this
time. A cold front is currently lingering just outside of our region
in central OH. This front is expected to move through the region
this evening and overnight and MVFR probabilities pick up quickly
behind this front (jumping to >70% for all ports save FKL/DUJ by
03z). IFR probabilities for all ports save FKL/DUJ peak north of 60%
by 06z.

Areas of rain and embedded showers are moving across much of the
region at this time. These showers are largely occuring in the VFR
realm but heavier showers are expected this evening with the chance
to bring MVFR restrictions and the possibility of bouts of IFR VIS.
Thunderstorms are not out of the question as there is some elevated
instability this evening. This chance would be highest south for MGW
and to a lesser extent HLG, however this was not viewed as high
enough to include at all in the TAFs but the possibility is worth
noting.

Outlook... The Upper Ohio River Valley will remain positioned
between a Central Plains trough and Atlantic ridge that will foster
multiple rounds of moderate to locally heavy rain through Monday
morning. Timing and shape in each wave remains variable, which may
alter the axis of highest precipitation rates and areas of greatest
restrictions. Aviation customers should anticipate limited windows
of VFR and dry conditions through the period as the pattern favors
MVFR/IFR restrictions, heavier rain showers and occasional
thunderstorms.

A deepening upper level trough may overtake the region early next
week, shifting towards a colder pattern featuring periodic rain/snow
chances and continued ceiling restrictions.

&&

.HYDROLOGY...
The potential for heavy rainfall will exist beginning tonight
and continuing into Sunday. At this time, areas across Ohio have
the potential to see the heaviest rainfall, where a Flood Watch
has been issued. Current NBM values indicate a 60 percent
chance or greater of at least 2 inches of rain over a 72 hr
period in this region. Lesser probabilities exist further east,
though a trend up has been noted in the latest ensemble guidance
and will need to be monitored for any potential expansion of the
flood watch. The exact location of the heaviest rain will
depend on the position of a quasi-stationary surface front.
Precipitable water is expected to remain elevated through
Sunday, with some periodic jet enhanced ascent. Even after the
heavy rain potential ends, river levels will likely remain
elevated for a few days. Current ensemble river forecast
projections also focus the most significant river rises across
Ohio.

Will monitor further trends for any future adjustments to the
watch.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
PA...None.
OH...Flood Watch through Sunday morning for OHZ039-040-048-049-
     057>059-068-069.
WV...None.

&&

$$

SYNOPSIS...Rackley
NEAR TERM...Rackley
SHORT TERM...Rackley
LONG TERM...Rackley
AVIATION...AK
HYDROLOGY...