Area Forecast Discussion
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816 FXUS61 KPBZ 251557 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 1157 AM EDT MON JUL 25 2016 .SYNOPSIS... A slow moving cold front will pass through the area this evening bringing the chance for scattered storms. A dry mid week before the weather pattern gets active Friday and Saturday. Above normal temperatures are forecast all week. && .NEAR TERM /THROUGH TUESDAY/... As we remain in the warm sector strong daytime heating has allowed the mercury to climb along with the heat index. As of 12pm Zanesville and Latrobe already has a 100F+ heat index. Expect the number of triple digit reports to increase as we see several more hours of sunshine and soundings do not show a lot of dry air mixing to the surface. Recent runs of the RAP model portrayed dewpoints getting into the lower 60s. Upstream there are no indications of that given parcel trajectories from that airmass 24 hours ago. Convective complex over western NY and Lake Erie will be the focus for storms this afternoon. Experimental HRRR did a great job on timing and coverage yesterday, so opted to roll with that again today for Pop forecast. This means any severe threat will be focused in our eastern zones /Venango south to Fayette/. The line will intensify as it reaches northwestern PA then traverses through the central part of the state during the early and mid afternoon hours. Meanwhile, daytime heating will ignite scattered thunderstorms elsewhere that will be very tall as SBCAPES are already over 4000 jkg-1 with no CINH. After looking at forecast soundings wet microbursts and brief downpours are the primary threats. DCAPES remain above 1000jkg-1 supporting strong downdrafts. Again, do not expect widespread severe weather, but isolated down trees are possible much like Sunday until the baroclinic zone crosses tonight. Weather will quiet down this evening as the cold front /in name only/ passes. There are still questions how far south the boundary gets. Recent runs from the NCEP suite have trended farther north keeping it just south of our forecast area in central WV. Thus, there could be a chance of showers and storms tomorrow south of the Mason / Dixon line. H8 temps do not drop more than 1-2C, so if you are looking for a reprieve to this heat, it is not in the cards. Dewpoints will be lower, however heat index values around 90F will be common Tuesday. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... Zonal flow aloft will keep the short term almost entirely dry. H8 temperatures around 18C will keep the area hot. No significant changes to the short term given the above two sentences. The timing of the next short wave could bring measurable precipitation to eastern Ohio Thursday night. && .LONG TERM /FRIDAY THROUGH SUNDAY/... Highlights: - Continued above normal temperatures - Best shot at rain arrives Friday - Chance of showers and storms has been extended into Saturday Active weather to start with a shortwave trough traversing the region. If timing gets pushed back, would not be surprised if severe weather becomes a possibility given its passage during the prime heating hours. With moisture surging out ahead, an extensive amount of clouds are forecast. Slightly more agreement amongst the ensembles and Superblend, opted to increase pops into the likely range Friday for much of the region. The mid level disturbance continues to move slowly east allowing the chance for showers and storms into Saturday as it lifts northeast through the Great Lakes. H5 heights and high pressure build into the region permitting dry weather Sunday and Monday, but again no signs of any cool downs. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... General VFR expected today in the warm, moist airmass ahead of an approaching front. A few showers have popped up across the region this morning, but they have missed the terminals to this point. Expect coverage to increase as we become more unstable this afternoon but with no definite line of showers and storms developing, have opted to carry VCTS in the TAFs. Restrictions will be limited to any terminal that experiences a thunderstorm. The rather diffuse front will slowly sag across the region through this evening, with a wind shift from southwest to west. .OUTLOOK /MONDAY NIGHT THROUGH FRIDAY/... Lingering low level moisture tonight may promote restrictions in fog. But after Tuesday morning, the next chance for restrictions will be with a late week front. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...Heat Advisory until 6 PM EDT this evening FOR OHZ039-048-049- 057>059-068-069. PA...None. WV...Heat Advisory until 6 PM EDT this evening FOR WVZ003-004-012. && $$ synopsis...98 near term...98 short term...98 long term...98 aviation...34 is the U.S. government's official web portal to all federal, state and local government web resources and services.