Scientific Forecaster Discussion
fxus61 kpbz 220136
Area forecast discussion
National Weather Service Pittsburgh PA
936 PM EDT Thu Jun 21 2018
slow moving low pressure will generate periodic shower and
thunderstorms chances into the weekend.
Near term /until 6 am Friday morning/...
the late eve update featured minor adjustments to hourly trends
of pops and temperature based on the latest observations.
The leading edge of precipitation on the eastern flank of broad
Midwest low pressure will continue to develop northward tonight.
The upper low/trough are projected to become more neutrally tilted,
slowing the progress of the associated warm front. Likely/categorical
pops follow this thinking.
No major flooding issues are anticipated for tonight based off
consensus of model quantitative precipitation forecast and limited instability.
Temperatures will remain above average overnight with the
approaching cloud coverage and escalating dewpoint.
Short term /6 am Friday morning through Saturday night/...
the upper low will drift north of the lower Ohio Valley on
Friday before beginning to open up and transition over the
Great Lakes Friday night and Saturday. Several rounds of rain
are expected through the period in the deep moist flow ahead of
the low. Have likely pops for Friday through Saturday.
Overall instability looks marginal as the low crosses the
region. Thunder cannot be completely ruled out...so have kept
mention of isolated storms in the zones. Rain chances finally
start to decrease Saturday night as the trough passes and the
lingering frontal boundary gets pushed south.
A limited diurnal range in temperatures is expected...
suppressed by the clouds and rain, with highs near or just below
normal, and lows above normal.
Long term /Sunday through Thursday/...
a shortwave on Sunday will increase precipitation chances on
Sunday...followed by high pressure and a return to dry
conditions on Monday. A warming trend in temperatures is
expected heading towards the middle of next week.
Aviation /01z Friday through Tuesday/...
VFR conditions are expected to degrade to MVFR when a warm
front moves northward over the area late tonight/early Friday.
Restrictions should then continue through the balance of the
current taf period as low pressure approaches the upper Ohio
Valley. Isolated thunderstorms could accompany showers Friday
periodic restriction potential continues through Mon as slow
moving low pressure crosses the area.