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NWS Area Weather Forecast Discussion
County Warning Area [CWA]: PBZ
Regional NWS Weather Office: Pittsburgh, PA

FXUS61 KPBZ 291414

Area Forecast Discussion
National Weather Service Pittsburgh PA
1014 AM EDT Sat Apr 29 2017

Unsettled but warm weather is expected through the weekend, with
a cold front expected for Monday.


Late morning update to once again adjust POPs as MCS continues
to advance across Ohio. Latest mesoscale models and 12Z NAM
show the area of showers and thunderstorms with the shortwave
weakening quickly this afternoon as it runs into the
strengthening east coast ridge. It appears rainfall rates are
beginning a slow decline on MRMS data, and with speed of system
movement, it appears the flood threat will not be widespread.
Will continue to monitor. Previous discussion follows.

Mid level shortwave is currently exiting the southeast ridges
with showers diminishing west to east mid morning. Next
shortwave with MCS moving into southwest Ohio will arrive for
the afternoon. Have adjusted POPs to try and place a small
window of mainly dry conditions mid morning into early
afternoon, but timing will be an issue. For now with lack of low
level instability and fast movement of approaching wave, severe
or flash flood threat remains low. No changes to temperatures
at this time as still expect front to attempt to shift north
later today.

Tonight as last shortwave exits developing mid
level ridge should be able to shunt front farther north,
bringing warmer and more humid conditions, and a lesser chance
for showers.


Warm front will remain near the New York border through Sunday
night as heights rise aloft. This looks to keep a cap on
widespread activity Sunday. With a mid level ridge on Sunday
much warmer and more humid conditions will develop. Ridge begins
to break down Monday as an occluded storm system in the western
Great Lakes pushes a cold front across the region, with showers
and thunderstorms with FROPA.


A closed low will eventually move across Southern Canada
Tuesday and Wednesday. The surface reflection will move directly
under the 500 low, keeping the chance for showers in the
forecast. A cooler and unsettled pattern will continue into
late week as a mean mid level trough remains across the ERN


Immediate concern at the beginning of the 12Z TAF period is low
level wind shear, with relatively light surface winds around a
warm front and strong westerly winds aloft. Latest computer
models suggest LLWS should have already come to an end, although
observations including VAD wind profile and upper air balloon
show these winds are still present. With models not much help in
this case, have included LLWS in TAFs other than FKL/DUJ through
15Z, and will reevaluate situation with later observations.

Showers and thunderstorms will continue to move eastward along a
slowly northward moving warm front today. This will mean they
will start the day mainly from KPIT southward, then gradually
transition northward toward KFKL/KDUJ after a gap through much
of the morning. A fairly potent wave should transition down the
front early in the afternoon, which will likely allow for the
best chance of thunderstorms as it passes most sites during this
interlude. As the warm front lifts north of the area Saturday
evening, most sites will scatter out, however some stratus may
linger around KFKL/KDUJ.

Restrictions are possible through Sun in vicinity of a surface
front. Restriction are likely with a strong cold front Sunday
night and Monday.





Forecast Discussion from: NOAA-NWS Script developed by: El Dorado Weather