Area Forecast Discussion
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000 FXUS61 KPBZ 161821 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 221 PM EDT Sun Jul 16 2017 .SYNOPSIS...
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Warmer weather with increased humidity can be expected today through the week. Wednesday appears to be the hottest day. Scattered storms are possible through Monday afternoon and evening.
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&& .NEAR TERM /THROUGH MONDAY/...
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Shortwave trough traversing the lower Great Lakes will continue to spawn showers and thunderstorms through the evening hours. By the time the pocket of mid level cooling reaches our forecast area it will be close to sunset. This will result in a weakening trend, however continue scattered pops over the far northwest through the overnight hours. As trough axis sweeps through Monday morning expect a fair amount of showers north of I-80, thus likely pops were continued. With advection of mid and upper level moisture do not expect fog to be a concern tonight. Would not rule out patchy fog in deeper gorges of northern WV, due to lower cloud coverage. Mixing depths do not change much the next 24 hours and with H8 temps not moving much either expect a near carbon copy of today for max temps.
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&& .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
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Storms that fire up on terrain and Erie lake breeze Monday afternoon will wane shortly after dusk owing to a precip free night. Locations that received rainfall during the day could be susceptible to fog development prior to sunrise. Very warm weather for mid week as H8 temps climb close to 20C. A passing weak short wave trough and lower heights will trigger isolated storms due to elevated heat source in the mountains. Upstream ridge and associated subsidence inversion should be able to cap atmosphere over eastern Ohio into western Pennsylvania Tuesday. Higher pops were confined to locations east of Pittsburgh and in the mountains of WV and MD. Temperature advection between H7-H5 increases from previous day giving more confidence that CWA will be precip free from popcorn afternoon storms. Very warm weather persists as overnight lows do not fall much below 70F and afternoon highs make a run at 90F save for the mountains. Wednesday should be the hottest day of the upcoming week. Heat index values will be in the lower 90s for places outside of the mountains. Bias corrected raw blend was used for temperatures.
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&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
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Highlights: - Potential for Ridge Runners - Typical Summer Like Weather Mid level anticyclone juxtaposition places region on periphery allowing for potential thunderstorm clusters to track over the region as they develop in the upper Midwest and Great Lakes. Timing still to early to pinpoint in forecast but for now will continue with chance pops until a more defined trigger Thursday and Friday is evident. Difference arise with long term operational models and confidence is not increased after reviewing their respected ensembles with the potential height falls next weekend with low pressure over eastern Canada. GFS and GEFS support slightly cooler weather than ECMWF given stronger amplification of aforementioned trough. Depending on which outcome occurs, temp difference between the two could be quite large from the lower 80s to the lower 90s. Of course precip chances will vary as well. Will hedge toward super blend of pops keeping numbers in the chance category.
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&& .AVIATION /18Z SUNDAY THROUGH FRIDAY/...
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Light southwest winds and VFR conditions through this evening. Low level moisture increases tonight coupled with light winds may lead to MVFR FG overnight. However this should be limited as mid level clouds will be on the rise. There will be scattered showers and thunderstorms mainly affecting FKL at the end of the forecast period. Overall confidence is high save for fog development during the predawn hours. .OUTLOOK... Low pressure passing through the Great Lakes will bring the next chance for restrictions on Sunday night and Monday.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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