Scientific Forecaster Discussion
fxus61 kpbz 202202
Area forecast discussion
National Weather Service Pittsburgh PA
602 PM EDT Fri Sep 20 2019
warm weather with only a slight rain chance can be expected for the
weekend. A Monday cold front will likely generate showers on Monday.
Near term /until 6 am Saturday morning/...
a shower remains possible early this evening for area west of I 77
across east central Ohio where moisture has increased under a weak
disturbance. Very warm mid levels and resulting lack of instability
is the primary inhibitor.
Otherwise, overall high pressure will keep the night dry, but with
temperature warmer than previous nights due to an increase in surface
moisture and overall column warmth due to advection aloft.
Short term /6 am Saturday morning through Sunday night/...
a weak shortwave trough will move off the Great Lakes on Saturday
and cross the I 80 corridor. This feature combined with destabilization
via higher surface dewpoints and warming may be sufficient for
afternoon convection; however, the lack of a thermal trough and
overall forcing for ascent should limit coverage and intensity.
The advance of a midwestern trough will result in warm southwesterly
flow and increased humidity for Sunday. Expect highs about 15
degrees above the seasonal average.
Long term /Monday through Friday/...
the central U.S. Trough, and its associated cold front, is progged
to cross the region Monday, with drier and cooler northwest flow developing
over the region Tuesday as the system moves east. Significant lift
along this boundary plus moisture advection ahead of it will make
rain likely for all areas.
Sfc high pressure and fairly weak zonal flow aloft is expected for
most of the week, resulting in dry weather and more seasonable
Precipitation chances may return at the end of the week with the
passage of a weak trough within the westerly flow.
Aviation /22z Friday through Wednesday/...
high pressure will maintain VFR. Increasing moisture under an
approaching, albeit weak, disturbance may support formation of some
MVFR stratocumulus on Saturday morning, but confidence is only
moderate at best. Any restriction should be alleviated by midday with
only isolated convection posing a problem thereafter.
restrictions are likely with a Monday mrng cdfnt.