Area Forecast Discussion
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FXUS61 KPBZ 250204

Area Forecast Discussion
National Weather Service Pittsburgh PA
1004 PM EDT SUN JUL 24 2016

A muggy night as the mercury only falls back to around 70. A cold
front in name only passes Monday afternoon bringing the chance of
a downpour. Dry for mid week, however above normal temperatures
are forecast to continue. Another cold front will cross in the
late Thursday - Friday time frame.


As of 10pm, all precipitation has left the region. Have added
overnight fog to the forecast in river valleys from Pittsburgh to
the north, considering that was the general area that saw heavier
rainfall earlier this afternoon. Light winds overnight will also
allow for fog formation, although high clouds could prove to be a
limiting factor. Dry conditions are expected into the early
morning hours, although the HRRR/RAP are a bit faster bringing
precipitation back to the region compared to other models, showing
that rain could reach northwestern counties before sunrise. Except
for ridge locations, temperatures are not expected to drop much
below 70 tonight.

A cold front will cross the region Monday afternoon on the
periphery of the mid level anticyclone. This will end the short
heat wave across the area as clouds and timing of the showers
should hold temps in the 80s. Much the case today, ample energy
to tap for storms, especially when morning cap erodes. Best
chance for any severe storm will be south of DUJ to PIT to ZZV
line at this juncture. Wet microbursts are possible given a water
loaded sounding. PWATS north of two inches once again support
brief heavy rain. As for a flash flooding threat, the jury is
still out given storms will be moving and training does not appear
to be an issue. The best timing for storms will be late morning to
midday hours in Ohio and mid to late afternoon for PA/WV/MD.

Temps were constructed using the Bias-Corrected Raw Blend given
recent performance.


The baroclinic zone will be east of the region Monday night. In
its wake lower dewpoints will return, however daytime highs will
remain above normal with widespread mid and upper 80s forecast.
Any residual fog from the previous day rain will scour out by
late Tuesday morning. Dry weather takes command through the
balance of the short term. Zonal flow aloft and a area of high
pressure traversing through the Great Lakes are the culprits for
the stretch of zero precip days. H8 temps slowly increase 1-2C
during this period so for the most part daytime highs will be
mirrors of each other.


- Continued above normal temperatures
- Best shot at rain arrives Thursday night into Friday

Overall no real change to synoptic pattern for much of the week
as a broad H5 anticyclone dominates the southern 2/3rds of the
CONUS. Our mid level height values will fall a few decameters,
but not enough to usher in temps where they should be for this
time of year. Based on H8 temps not see a stretch of
90F+ weather like this weekend. However, would not be surprised
for eastern Ohio to be right around 90F for daytime highs most of
the week.

Baroclinic zone that crosses Monday night weakens and washes out
over the central Appalachians Tuesday as flow become parallel to
the boundary and it encounters increased subsidence. In its
wake, slightly cooler weather than what we have experienced
takes hold for mid week. By weeks end, another shortwave trough
traverses the region sweeping a cold front through. Timing
differences reside with ECMWF and GEFS, but ECMWF keeps the
recent summer trend going of shortwaves passing outside peak
heating hours. GFS opts for a Friday afternoon passage. Either
way, the next shot of widespread precipitation appears to be
Thursday night into Friday. Zonal flow re-establishes for the
weekend with temperatures near the climo average of lower to mid


Although the forecast calls for VFR conditions overnight except
for MVFR fog at FKL/DUJ, this forecast may turn out to be too
optimistic. Am unsure as to just how widespread fog may be at
other terminals overnight considering heavier rainfall that
occurred today, especially along the BVI-PIT-AGC corridor. In
addition, DUJ has had a couple hours of LIFR stratus, and although
the forecast calls for this to eventually scatter out, this is not
a high confidence forecast either.

A cold front will cross the region on Monday, and although
widespread restrictions are not expected with the front, any
heavier showers/thunderstorms will have the potential to bring

After the passage of the cold front Monday night, no widespread
IFR conditions are expected at this time.




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