Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Pittsburgh PA
843 PM EDT sun may 3 2015
high pressure will bring dry and warm weather through Monday
afternoon. An approaching front brings rain chances by Monday
Near term /through Monday/...
changes to the forecast this evening were mainly concentrated on
starting trends out closer to the highly varied temperature field
going into the evening hours. With a non-uniforming mixing
profile late this afternoon and evening due to weak momentum in
the mixed layer...highs varied generally from the middle 70s to
lower 80s across the County Warning Area. Going into tonight...very strong
inversions are noted on model soundings...and as a
result...thermal belts in the ridges were strengthened in the
grids tremendously. This had a big impact on the relative humidity recoveries
overnight...making them very poor in the ridges. Likewise...going
into Monday...layer momentum below the mixing height increases
drastically from the southwest. This will increase dewpoint values
through the day...and likewise allow for a more uniform mixed
profile. As a result...temperatures should have no difficulty in
skyrocketing during the morning before a more pervasive cumulus
field develops. Fries
Short term /Monday night through Tuesday/...
surface high pressure off the coast will keep southwesterly winds
across the region through the period...resulting in continued
warm air advection. Daytime maximum temperatures will be approximately
10 degrees above normal. Probability of precipitation increase late Monday as moisture
advection ramps up out ahead of a boundary slowly transitioning
south across the forecast area.
Long term /Tuesday night through Sunday/...
warm temperatures will be the weather highlight through the
extended period as ridging remains in place across the eastern
states. Temperatures are expected to range between 10 and 15
degrees above the averages.
The best chance of any precipitation still looks to be Tuesday
into Wednesday morning as a frontal boundary slides over the
upper Ohio region. Forecast soundings show marginal
instability...but improved moisture...middle level thermal
troughing...and afternoon warmth may support some thunderstorm
development...with better chances over higher terrain.
Aviation /01z Monday through Friday/...
high confidence VFR forecast the next 24 hours. Winds will
subside around dusk and back around to the south. As the pressure
gradient picks up Monday...winds will be gusty from the southwest
during the afternoon hours. Hill Top airports could eclipse
20kts...while most airports will experience sustain speeds around
12kts. With daytime heating high based cumulus will develop around
midday. Middle and high clouds will invade from the west ahead of the
next low pressure system.
Outlook.../Tuesday through Thursday/...
the next chance for general restrictions will come with a Tuesday