Scientific Forecaster Discussion
fxus61 kpbz 260233
Area forecast discussion
National Weather Service Pittsburgh PA
1033 PM EDT sun Jun 25 2017
upper low pressure will maintain cooler temperature and a periodic
shower chance for the first half of the week.
Near term /through Monday/...
the late eve update included some adjustments to pops as a weak
lead shortwave is spawning some showers in Lee of Lake Erie.
Slight/isolated numbers should suffice for areas north of I 80
Another, albeit deeper shortwave is projected across the Great
Lakes this afternoon. Improved lapse rates and falling convective
thresholds under cooling mid levels all support escalating
precip probability with the surface reinforcing front, but with
inhibitions by moisture paucity. No major changes were needed
to the ongoing forecast of eventual scattered showers, a slight
thunderstorm chance with more numerous convection over the I 80
Cold advection will hold temperatures about 10 degrees under the
Short term /Monday night through Tuesday/...
mean troughing will remain across the area through the short
term period. This combined with the passage of a more vigorous
mid-level system will allow for rather unsettled conditions with
scattered showers throughout the period. With reinforced
cooling, temperatures will remain well below average.
Long term /Tuesday night through Sunday/...
the pattern rapidly evolves to favor flat ridging moving toward
the Appalachians by the latter half of the work week. However,
the lack of deepening of the system that shifts toward the upper
Mississippi Valley combined with a fairly weak subtropical ridge
off the southeastern U.S. Coast will mean moisture advection
should occur fairly readily over the Flat Ridge. As such, while
a short period mid-week looks dry, humidity and thunderstorm
chances should return with warmer air later in the week.
Aviation /03z Monday through Friday/...
skies should be mostly clear overnight with light westerly
winds. A cold front approaching the region on Monday should set
off scattered showers and thunderstorms, especially north of
Pittsburgh. Prevailing precipitation is expected at fkl/duj, but
only had enough confidence to mention vicinity showers at bvi.
At this time, not enough confidence in precipitation occurring
at the rest of the terminals to mention in the tafs. West winds
should gust to around 20 kt during the afternoon hours.
brief restrictions are possible with showers and scattered
storms Tuesday with the passage of the upper trough axis.