Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
1027 am EDT Wednesday Jul 29 2015
warm and muggy today...then less humid later tomorrow into late
week behind a cold front.
Near term /until 6 PM this evening/...
a warm and humid day is in store for the region with temperatures
ranging from the middle 80s to lower 90s and dewpoints in the middle
60s. An isolated shower or two will be possible over the ridges by
late afternoon...and potentially across eastern Ohio / northwest PA zones
ahead of the approaching front. The only change from the
inherited forecast was to slightly increase maximum daytime
temperatures. This change was based off of 12z soundings and
latest bias corrected model data which has been performing well
with the above average temperatures over the past couple days.
Short term /6 PM this evening through Saturday/...
cold front will pass over the region tonight...with continued
chance probability of precipitation. Overnight timing and a fairly capped atmosphere will
keep only chance probability of precipitation in the forecast with frontal passage. Lower dew
points will begin to work into the region during the day Thursday
as scattered showers and storms diminish northwest to southeast.
As upper level trough develops into the eastern states northwest
flow aloft will keep lower dew points with near seasonal
temperatures into late week. Added low chance probability of precipitation for Saturday
as models look to bring a shortwave in northwest flow and a
reinforcing cold front.
Long term /Saturday night through Tuesday/...
surface ridging is prognosticated to continue under broad eastern Continental U.S.
Upper troughing...bringing mainly dry and seasonally warm weather
into the early part of the week. Precipitation chances are expected to
return Tuesday into middle week with crossing shortwaves. Followed
close to wpc ensemble based guidance...which smooths out some early
week operational model differences.
Aviation /14z Wednesday through Sunday/...
VFR conditions with diurnal cumulus are expected through the afternoon.
An advancing cold front will bring increasing shower and
thunderstorm chances to ports west of the PA border by this
evening...so included a thunderstorms in the vicinity mention at zzv. How long precipitation
continues along the front is in question as it moves into PA later
in the evening...so only included a vcsh mention for the rest of
the taf sites.
Outlook...Thursday through Sunday...
restrictions are possible with a Saturday cold front.