Area Forecast Discussion
Issued by NWS

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KPBZ 201848 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 248 PM EDT Thu Jul 20 2017 .SYNOPSIS...
-- Changed Discussion --
Strong to severe thunderstorms remain possible this afternoon and evening ahead of a front. After a relatively quiet Friday, a wet weekend appears likely, perhaps with more strong storms Saturday.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Storms have started to form along a boundary between two thunderstorm complexes...one an old MCS/MCV diving into southwest Ohio, and another bringing severe weather to western New York. This broken line of storms should progress south and east across the region through this evening. These are forming up in an air mass northwest of PIT with perhaps 1000-2000 J/kg of CAPE and 30-40 knots of effective bulk shear. This should be sufficient for a few strong to severe thunderstorms, although the threat may be a bit lower than previously anticipated. Wind will be the primary hazard, as wet bulb zero heights are too high, and CAPE aloft is too low, for much of a hail threat. An isolated tornado remains possible as well. Have continued with likely PoPs across the northern half of the CWA through the evening hours. Coverage and intensity should slowly fade after sunset, with a few scattered showers and storms remaining in the vicinity of the Mason/Dixon line by sunrise as the boundary slowly advances. Abundant cloud cover and humidity will keep low temperatures several degrees above climatology.
-- End Changed Discussion --
&& .SHORT TERM /FRIDAY THROUGH SUNDAY/...
-- Changed Discussion --
Will hang on to some slight chance PoPs on Friday across the southern counties as there is still a touch of uncertainty just how far south the boundary will be pushed by tonight`s activity. The models also look a touch slower with the next wave in the northwest flow pattern, and have backed off precip chances a bit here. The weekend looks wet, as Great Lakes low pressure passes to the north, and several shortwaves run down the northwest flow. Flow over our area turns more zonal by Sunday, which will slow progression of the associated frontal boundary. Kept likely PoPs going through this period with several rounds of rain expected. Rainfall totals will have to be watched for problematic areas. Additionally, there appears to be a risk for severe storm Saturday, especially if some cloud breaks can form, given decent mid-level flow. Temperatures will start a slow fall this period, held in check by the clouds and rain. Minimal changes were made.
-- End Changed Discussion --
&& .LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
-- Changed Discussion --
A general Great Lakes/northeast U.S. trough will be carved out by Monday, with this pattern holding into mid-week. Temperatures will fall back to near or just below normal during this period. After lingering precipitation Monday, Tuesday and Wednesday appear dry at this distance. A return to northwest flow may herald increasing rain chances Thursday.
-- End Changed Discussion --
&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/... High confidence forecast save for the onset and duration of thunderstorms this afternoon and early evening. These times could vary by 2-3 hours and flight category between 6-12Z Friday. An upper level disturbance crossing this afternoon will bring a line of strong to severe storms moving from north to south affecting likely all terminals if it develops like many of the high resolution models indicate. Inserted VCTS for all terminals starting around 20Z north and 0Z south of the mason dixon line. Brief restrictions to IFR vis can be expected if an airport is impacted by a storm. In wake of the storms, last 6-9 hours of forecast its hard to tell if MVFR fog will develop or will there be a canopy of stratocu or just VFR? For now, rolled with an optimistic forecast no cigs below 030. .OUTLOOK... Additional rounds of storms are expected through the weekend, and morning fog is possible as well. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.