Scientific Forecaster Discussion
000 FXUS61 KPBZ 300508 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 108 AM EDT Thu Mar 30 2017 .SYNOPSIS... Wrapped-up low pressure will bring rain to the upper Ohio Valley late Thursday through Friday. && .NEAR TERM /THROUGH TODAY/... Midnight update made to make only minor tweaks to the forecast based on the latest observations and trends. Incoming thin cirrus and strengthening warm advection may limit cooling overnight. Thus, low temperatures were bumped up slightly based on the latest hi res guidance. Occluded low will move slowly eastward today toward the upper Ohio Valley. Much of the region should remain dry until late, however as we remain situated under an upper ridge. Only exception to this is north of I-80 where moisture spilling over the ridge and isentropic ascent support some rain showers by this afternoon. Opted to carry coverage wording for the precipitation expected through this evening. Otherwise, daytime mixing should allow for temperatures to warm to slightly above averages today despite increasing cloud cover. && .SHORT TERM /TONIGHT THROUGH SATURDAY/... Showers will continue everywhere Friday morning, with the chances for showers beginning to diminish Friday afternoon and Friday night. Lingering low level moisture may keep widely scattered showers possible through the first part of Saturday before building subsidence brings an end to precipitation. Above normal temperatures are forecast on Friday before dropping to at or slightly below normal values for Saturday. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... While the second half of the weekend will be dry, showers will begin to threaten the area on Monday, with Monday night having the greatest chance for showers. While showers could possibly hold on into Tuesday, a bit of model uncertainty develops for the timing of the next low pressure system to arrive. Some model guidance shows rain moving in on Wednesday, with other guidance delaying rain until Thursday. Temperatures will generally stay close to or slightly above average for early April. && .AVIATION /06Z THURSDAY THROUGH MONDAY/... Though general VFR is expected for today, marred by possible scattered showers this afternoon, a gradual deterioration can be expected late as deep low pressure shunts moisture and develops a tightening pressure gradient over area terminals. Showers, general MVFR, and low level wind shear can all be expected after dark tonight. Outlook... Restrictions are likely through Saturday as broad low pressure moves slowly across the region. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None.