Area Forecast Discussion
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FXUS61 KPBZ 242253
Area Forecast Discussion
National Weather Service Pittsburgh PA
653 PM EDT TUE MAY 24 2016
Mostly dry weather is expected through Wednesday. A weak
disturbance will provide a chance of rain starting Wednesday
night. A slow warming trend will continue through Friday.
.NEAR TERM /THROUGH WEDNESDAY/...
With 6pm update, minimal changes were made to sky cover and hourly
trends for temperature. Previous discussion follows.
A 500 mb ridge will keep the forecast area dry over the next 24
hours. Overall moisture in the column is fairly limited, but still
enough for some diurnal cumulus this afternoon. These will
collapse towards sunset. Mostly clear skies are forecast
overnight, although a bit of cirrus may spill over the ridge
late. Low temperatures will be seasonable, but still a few degrees
The upper ridge shifts east on Wednesday, and increasing southwest
flow will start the process of increasing dewpoints. More diurnal
cumulus are expected. Although low-level instability will start to
increase, a mid-level cap will keep convection at bay for much of
the area. Southeast Ohio may get just moist enough to break the
cap for a few isolated showers and storms after 18Z, and have
slight chance PoPs here. With rising 500 mb heights and 850 mb
temperatures, we expect afternoon highs to be a few degrees
warmer than today.
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
A weak shortwave trough in the midst of an unstable atmosphere is
progged to slowly pass on Thursday. Hence, showers and thunderstorms
are expected to develop in the afternoon and evening.
Unstable conditions will continue into Friday as the broad ridge of
high pressure strengthens and terrain driven diurnal thunderstorms
Very warm and humid conditions are expected through the period via
southwest flow with temperatures forecast to be at least 10 degrees
above average. Have used a blend of GFS, NAM, and WPC guidance for
temperatures as a broad and anomalously strong ridge pattern holds
across the region.
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The ensemble members continue to be in good agreement that the
aforementioned ridge enhances. Above average temperatures with
humid conditions are expected. Saturday appears to be the warmest
day of the period as the ridge axis is progged to be very near or
directly over the forecast area while mid-level heights have
reached their maxima.
The overall broad ridge of anomalously high pressure over the
Eastern US remains certain through the period and thus near WPC
values for temperatures were used. Diurnal convection can be
expected each day and so chance pops have been maintained.
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR into Wednesday afternoon underneath high pressure. West winds
under 10 kts this evening will become southwest under 5 kts
.OUTLOOK /WEDNESDAY THROUGH SUNDAY/...
The next chance for restrictions will come with the advance and
passage of a disturbance wednesday evening and Thursday.