Area Forecast Discussion
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000 FXUS61 KPBZ 190458 AAC AFDPBZ Area Forecast Discussion...UPDATED National Weather Service Pittsburgh PA 1258 AM EDT Mon Aug 19 2019 .SYNOPSIS... Warmth, humidity, and daily thunderstorm chances will continue through midweek. && .NEAR TERM /THROUGH TODAY/...
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Overnight PoPs were updated in line with the latest hires model guidance and radar trends. Increased PoPs ahead of the line, but decreased them later tonight as the activity encounters a more stable atmosphere. Much of the convection is currently being driven by a rather impressive shortwave that is interacting with an area of higher cape. It also appears the northern part of the line gusted out, thus creating a rather large gust front. The outflow is influencing strong development on the southern portion of the line. Surface cool front will quickly pass through the region as the shortwave trough picks up speed in the tightening zonal flow aloft. Models are in descent agreement that the atmosphere will continue to stabilize overnight. Even with this, will need to leave in thunder as impressive upper level wave will provide enough large scale ascension to allow convection to continue to fire. Little change to overnight temps. Shortwave trough and surface boundary will move east of the region this morning. Upper level flow behind the wave will return to zonal with a bit of a curve toward the NW. Weak surface high pressure will settle in over Ohio this morning, and the atmosphere will dry out. Even though we had FROPA, it will do little to nothing to evacuate the humid conditions. Because of this, the atmosphere will still contain plenty of buoyancy. The good news is that the real unstable air will establish itself south and west of the region. Additionally, there is no real trigger to initiate convection today, absent daytime heating. Still will need to keep in at least low chance PoPs today due to the aforementioned atmospheric conditions. If convection can fire, there will be enough instability to sustain updrafts, which in turn will eventually create outflow boundaries, which could develop new convection. This will all need to be watched throughout the day. As mentioned previously, it will remain warm and muggy today.
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&& .SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
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Zonal flow, north of a Southern CONUS high, is expected to persist across the region Tuesday. Shortwaves embedded in the flow should maintain periodic shower and thunderstorm chances as warm and humid conditions continue. A trough, and its associated cold front, are expected to track from the Upper Midwest to the Upper OH Valley/Great Lakes regions by Wednesday. Starting to see timing differences with this feature, so pulled back on PoPs.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
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Surface high pressure building under NE CONUS upper troughing should return dry, cooler and less humid weather by Thursday and Friday.
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&& .AVIATION /06Z MONDAY THROUGH FRIDAY/... General VFR is anticipated outside of isold to sct convection. The better chance of that occurrence will be for BVI and FKl, but all sites wl have a vcsh mention for the overnight passage of a decaying storm complex. .Outlook... Mainly aftn/eve restrictions are possible thru Tue with diurnal tstms. Restrictions are likely with a Wed cdfnt. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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