Area Forecast Discussion
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922 FXUS61 KPBZ 011747 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1247 PM EST Wed Mar 1 2017 .SYNOPSIS... The advance of a strong cold front has brought showers and thunderstorms to the Upper Ohio Region for today. Much cooler temperatures will then last through much of the weekend. && .NEAR TERM /THROUGH TONIGHT/... The third batch of rain supported by the upper shortwave us swiftly pushing east. Currently, greatest severe weather threat remains SE of PIT where better instability and shear are. Moderate rain will continue for the next hour or two before a break occurs with subsidence ahead of the cold front currently lagging in Indiana. Will hold on to the flash flood watch given the moderate rain still over the CWA and on-going flooding. Visible imagery shows clearing west of the area and near term hi-res models forecast convection to develop and cross the region in the late afternoon. The strength of the line of progged convection is uncertain at this time and will depend on how unstable the lower atmosphere can get before the front arrives. Nonetheless, strong wind gusts are likely to occur if thunderstorms develop due to significantly strong wind shear. Late day cold frontal passage will end the severe weather threat and return cold and snow showers chances to the region. Wind gusts behind the front are expected to reach advisory criteria as cold advection at the top of the boundary layer improves mixing. A wind advisory will likely be issued for tonight once current convection moves out of the CWA. && .SHORT TERM /THURSDAY THROUGH FRIDAY/... After the FROPA, upper troughing, cold advection, and limited lake and terrain enhancement should result in scattered snow showers through Thursday as temperatures return to sub average. Clipper system which has been well-advertised by the models digs over the region on Thursday night with some accumulating snow expected. Snow showers should linger and possibly reenhance Friday afternoon with steep low-level lapse rates. Accumulation rates may initially struggle with warm ground, but cannot rule out the eventual need for a winter weather advisory in at least the ridges. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Troughing pattern in the wake of the clipper Saturday transitions to a more zonal/flat ridge pattern for Sunday and Monday, and then a more amplified pattern once again by Tuesday with another trough/front approaching. Mainly dry weather for Saturday may be followed by a weak disturbance on Sunday, and then better precipitation chances thereafter as southwest flow and moisture ramp up again. Below average temperatures at the start will rise moderate early in the new week. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... The first round of precipitation is moving east of the area as of this writing. Lingering MVFR ceilings for the next hour should rise to VFR during the next few hours. The cold front is expected to move across the area between 21Z and 03Z, with a broken line of thunderstorms accompanying it. Handled with VCTS for now, as exact timing is still a bit questionable and any IFR restrictions from these storms should be brief. Winds should pick up again behind the front, with gusts to 40 knots out of the west possible. Wind gusts will continue through the night, slowly diminishing late, as MVFR or low-end VFR ceilings linger. Post-frontal rain showers should change to snow showers overnight before mostly ending towards morning. VFR ceilings may redevelop at several terminals by 18Z as winds continue to diminish. .OUTLOOK... Periodic restrictions are likely through Friday as cold low pressure crosses the region. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...Flash Flood Watch until 8 PM EST this evening for MDZ001. OH...Flash Flood Watch until 8 PM EST this evening for OHZ057>059- 068-069. PA...Flash Flood Watch until 8 PM EST this evening for PAZ029-031- 073>076. WV...Flash Flood Watch until 8 PM EST this evening for WVZ003-004- 012-021-509>514. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.