Area Forecast Discussion
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000 FXUS61 KPBZ 181901 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 201 PM EST Sat Nov 18 2017 .SYNOPSIS... Periods of rain along with a few isolated thunderstorms expected today as low pressure moves towards the region. A strong cold front will cross tonight bringing strong winds and a changeover to snow showers by early Sunday morning. && .NEAR TERM /THROUGH TONIGHT/...
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Bulk of heaviest rain will continue to shift northward, with a bit off a lull expected until the front approaches tonight. We should still see temperatures rapidly warm in advance of the front, which may offer up just enough instability for a rumble of thunder so we will keep this in the forecast through the early eve. Still expecting a period of strong winds with the front as it crosses and behind with as lapse rates steepen. While pressure rises are rather impressive, this will be just along the frontal boundary, which may lead to the need for a special weather statement, but not long enough to hoist an advisory as none of the other model guidance, bukfit soundings etc, suggest widespread and prolonged advisory-level conditions. Will leave the current wind advisory for the terrain as is, as conditions will linger there.
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&& .SHORT TERM /SUNDAY THROUGH MONDAY/... The upper trough will pivot across the region Sunday with a changeover to snow at most locations by daybreak. Northwesterly flow will continue scattered snow showers and keep temperatures in the 30s through the day. Highest PoPs remain the snow belt north of I-80 and in the mountains of PA/WV/MD where lake enhancement/upslope is anticipated. Still thinking 2-3 is reasonable, though some higher amounts may be possible. Depth of saturation will quickly fall below the prime snow growth zone in building subsidence in the terrain, which should keep rates down. Snow showers will continue through Sunday night as another reinforcing shortwave digs across the region. Conditions should begin to improve on Monday, as a surface high builds eastward and winds back toward the west. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Minimal change was needed in the extended. The majority of the week will be dry with seasonal temperatures outside of a weak wave progged to pass to the north midweek. Have kept slight chances in for locations north of I80 on Wednesday. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... Widespread MVFR at the start of the TAF period, save for near MGW in the warm sector, and IFR near/north of I-80. Expecting general MVFR to continue through the frontal passage tonight. Still a brief period of MVFR could creep as far north as PIT/AGC later this afternoon, and likewise brief IFR conditions will be possible in any heavier shower. Low level wind shear remains a concern this afternoon as strong winds remain trapped above a surface-based inversion. Stronger gusts are expected to reach the surface later this evening and overnight with the front. Peaks of 30-40 knots are expected in general, with some gusts up to around 45 knots expected on the ridges. Behind the front, MVFR conditions will linger. Rain showers will mix with and change to snow showers with time, with coverage tapering. Gusty winds will continue out of the west and northwest behind the front. .Outlook... Restrictions are likely with Sun/Sun night upper troughing and cold NW flow. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...Wind Advisory from 7 PM this evening to 10 AM EST Sunday for MDZ001. OH...Flood Watch until midnight EST tonight for OHZ039>041-048>050. PA...Flood Watch through late tonight for PAZ007>009-013>016- 020>023-029-073-074. Wind Advisory from 7 PM this evening to 10 AM EST Sunday for PAZ074-076. WV...Flood Watch until midnight EST tonight for WVZ001-002. Wind Advisory from 7 PM this evening to 10 AM EST Sunday for WVZ510>514. && $$

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