Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
737 PM EDT Tuesday Sep 16 2014
dry and seasonable cool conditions can be expected into Friday.
Near term /through Wednesday/...
low level moisture is quickly being eroded across the area as high
pressure builds in and a bit drier air mixes in from the
northwest. Dewpoints in the upstream air mass are not quite as low
as the air mass from prior to the cold frontal passage...so
widespread frost is not really anticipated. However...strong
radiational cooling will likely lead to a fair amount of fog
overnight toward morning...particularly in the lower spots of the
forecast area. As a result...lows in most places seem poised to
remain in the lower 40s. Fries
Short term /Wednesday night through Friday night/...
a shortwave will push a reinforcing cold front across New York
state Thursday. This will bring more clouds daytime Thursday but
not enough moisture to put in any probability of precipitation. Otherwise cool high
pressure will dominate with below normal temperatures.
Long term /Saturday through Tuesday/...
a warm up expected for the early weekend as the surface high shifts
well east of the area and upper level flow becomes more zonal.
Temperatures will...at least temporarily...return to near average Sat/sun
ahead of the next system. The best chance of precipitation over
the next 7 days will come with an elongated trough and associated cold
front sun with possible showers with cold air aloft Monday. Cool
high pressure Tuesday.
Aviation /00z Wednesday through Sunday/...
skies will go clear this evening. This will combine with
light winds and recent rainfall to produce areas of fog
late tonight...particularly in the valleys. Expecting IFR or LIFR at
all terminals around daybreak. Fog will burn off by 14-15z...leaving
scattered VFR cumulus.
Outlook...Tuesday night through Saturday...
outside of the possibility of valley fog one or two mornings...VFR
conditions are expected through the week.