Area Forecast Discussion
Issued by NWS Pittsburgh, PA

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000 FXUS61 KPBZ 180519 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 119 AM EDT Mon Mar 18 2024 .SYNOPSIS... Scattered snow showers are expected on and off through Tuesday morning with a crossing upper trough. Dry weather is then expected as temperatures will gradually warm mid to late week. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
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KEY MESSAGES: - Lake enhanced showers continue mainly north of Pittsburgh - Colder temperatures arrive tonight, especially over the southern half of forecast area ------------------------------------------------------------------- No changes needed for the early overnight update... Deep and cold trough over the Great Lakes will gradually move south overnight. 500 mb heights will fall another 70 meters or so as a result. The column will continue to cool and especially the boundary layer, with 850 mb temps falling from about -4C this evening to -11C in the PIT area by 12z Monday. Coverage of snow showers has become more sparse into the early overnight with the loss of diurnal heating. However, the loss of insolation has promoted some minor accumulation in the more moderate snow showers as seen on area webcams, especially along and north of I-80. A light dusting to perhaps a brief half inch is possible for those locations.
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&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM TUESDAY/... KEY MESSAGES: - Cold and unstable under upper trough with showers of snow and graupel. - Potential for light snow accumulation, mainly north of I 80 and in the higher terrain ------------------------------------------------------------------- Upper trough will start the day over northwest Ohio and Lake Erie, moving to western PA and WV by the late afternoon. Strongest height falls of 150 meters will be over VA. A very cold and unstable airmass is expected given we have mid March sun angle. 850 mb temps will be around -10C, 700 mb -18C, and 500 mb dropping to around -35C. RAP soundings show moist and unstable situation with diurnal heating under trough with increasing moisture and even 100-300 j/kg of CAPE. Cloud tops will be in the -20 to -25C range, so vigorous convective snow showers are expected which certainly could produce brief heavy snow bursts and graupel. Accumulations outside of ridges will be limited by March sun angle. However, with convection continuing into the evening, there is certainly the potential for accumulations north of I-80 and over the ridges Monday night. CIPS analogs indicate that the WV ridges have a 30-50% chance of 4" or more in patterns like this. At this point expect 2-3" in those areas so expect a sub-advisory event especially during the daylight hours. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... KEY MESSAGES: - Near normal temperatures expected Tuesday through Friday - Mainly dry weekend with moderating temperatures ---------------------------------------------------------------- As heights gradually rise and flow turns from northwest to westerly aloft, a low pressure area over the Great Lakes will skirt mainly north of the forecast area as it heads toward Ontario/Quebec/New England Tuesday into Wednesday. Certainly could be snow in the northern half, especially Tuesday morning, but the system will have limited moisture so the precipitation shield is more likely to impact New York and far northern PA. Flow gradually tilts from westerly to southwesterly as the week progresses with gradually rising heights and moderating temperatures. While near normal readings are expected most of the week, moderation begins over the weekend with highs in the 50s Saturday and Sunday. && .AVIATION /05Z MONDAY THROUGH FRIDAY/... General VFR forecast with the exception of FKL and DUJ which will see occasional MVFR conditions with snow showers. Gusty winds will continue through the night, but should weaken as the night progresses. Snow showers will become more prevalent and widespread on Monday. Difficult to pinpoint when and where they will hit, with FKL and DUJ having the highest probabilities to see restrictive vis/cigs. Winds gusts are again possible on Monday, but not as strong as today. .Outlook... VFR returns Wednesday and Thursday as a ridge of high pressure builds in && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Rackley NEAR TERM...Craven/Rackley/MLB SHORT TERM...Craven LONG TERM...Craven AVIATION...Craven

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