Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
248 PM EDT Tuesday Jul 29 2014
temperatures will moderate toward normal by late week with the best
chance for showers on Wednesday.
Near term /through Wednesday/...
tonight diurnal cumulus will dissipate but strato cumulus in northwest flow
will continue. Clouds will also be increasing as next shortwave
approaches tonight. On Wednesday left chance probability of precipitation with shortwave
pushing across region under closed low across eastern Canada.
Temperatures will again be well below normal especially with
clouds and scattered showers Wednesday. Enough cape for
thunderstorms Wednesday but would expect small hail at best with
very limited severe potential. Temperatures a close blend of model MOS.
Short term /Wednesday night through Friday night/...
shortwave exits Wednesday night with showers ending. Upper level
trough then begin to lift out as closed low begins to shift west
with heights rising off the East Coast. Temperatures will
gradually warm through the period and approach seasonal averages
Friday. Showers chances will linger mainly toward I-80 Thursday
afternoon closer to lake moisture and colder temperatures aloft.
On Friday flow aloft will begin to shift to the southwest allowing
deeper moisture to advect north. Models differ on how fast and
where this will occur...but would expect better moisture to begin
to move up along the ridges before increasing farther west toward
Ohio. For now chance probability of precipitation most locations Friday.
Long term /Saturday through Tuesday/...
although the mean trough maintains through the weekend...h500
heights will have recovered to the point that allows seasonable
temperatures. Dew point will remain comfortable without any
significant moisture influx from the south. A shortwave may provide
decent rain showers/thunderstorms and rain coverage Saturday afternoon/evening...while
Sunday will see a return of more sparse precipitation behind this
disturbance. There are hints that the trough may try to lift out
early next week...at least temporarily. This may lead to little or
no afternoon precipitation by Tuesday...as well as continued seasonable
Aviation /18z Tuesday through Sunday/...
VFR stratocumulus will continue through the afternoon into the
evening hours with skies generally overcast...but could still see
an isolated MVFR ceiling during the afternoon hours. Clouds should
scatter out somewhat overnight...with the potential for some MVFR
fog at zzv with light winds expected. Clouds will build in once
again on Wednesday...with scattered showers developing across the
region. Not enough confidence to include prevailing showers at
this time...and have just included vcsh for now. There will only
be a slight chance of thunder...so that was not included in the
Outlook.../Wednesday night through Sunday/...
no widespread rstrns expd.