Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
900 PM EDT Wednesday may 6 2015
upper level ridge will maintain above normal temperatures through
the the start of the weekend with scattered showers and storms
possible each afternoon...mainly over the higher terrain.
Near term /through Thursday/...
activity on radar has trended down significantly over the past
hour...with nothing much to note at the moment other than several
outflow boundaries still propagating across the forecast area.
No anticipating these outflows to trigger any further convection
as latest mesoanalysis shows instability decreasing significantly
in the lowest 100mb and based on radar returns the outflow
boundaries only extend to roughly between 2-2.5kft above ground level.
With that in mind made a couple minor adjustments to the forecast
for the remainder of the evening. Although a stray shower may
still occur over the next couple hours...removed any remaining
mention of precipitation...and with less cloud
coverage...temperatures were also trended down slightly as well.
With that and the fact dewpoints are still hovering in the upper
50s to low 60s...included a mention of patchy fog across the
region mainly after midnight until shortly after sunrise.
There will be a lesser chance for showers and thunderstorms
tomorrow as ridging builds in across the region...with any
activity that does develop expected to be limited to higher
terrain. Temperatures will persist well above seasonal averages
through the period.
Short term /Thursday night through Saturday/...
the story will remain much the same through the short term as the
region remains under the influence of a building upper ridge. With
the airmass generally remaining Continental...meaning little
influence from the Gulf...moisture will be rather limited for
widespread convection through the entire period...despite the
models suggesting quantitative precipitation forecast. Thus...only low end chance probability of precipitation for
diurnal showers and storms were maintained in the forecast as a
strong lifting mechanism will be absent. Late Saturday afternoon a
passing shortwave may bring the best chance for showers to eastern
Ohio...but as of right now will not get to aggressive with probability of precipitation.
Above average temperature will persist...with middle to upper 80's
possible by Saturday which is 10-15 degrees above normal.
Long term /Saturday night through Wednesday/...
upper level ridge will begin to weaken Sunday with a general
southwest flow aloft allowing increasing shower and thunderstorm
chances Sunday afternoon. Fairly strong upper level trough and
cold front then approach Monday with front crossing region Tuesday
morning. Much cooler high pressure follows for Wednesday. Previous
forecast quite close to wpc extended forecasts with only minor tweaks
Aviation /00z Thursday through Monday/...
the remainder of the night will be quiet as with any
shower/thunderstorm activity done for the night. There is potential
for IFR fog to develop across the terminals around dawn...with IFR
ceilings at kfkl and kduj. Conditions will gradually improve to VFR as
daytime heating initiates.
Outlook.../Friday through Monday/...
restrictions in fog possible Friday morning. Next chance for
widespread restrictions will be Monday with an approaching cold