Area Forecast Discussion
Issued by NWS Pittsburgh, PA
Issued by NWS Pittsburgh, PA
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597 FXUS61 KPBZ 070935 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 535 AM EDT Fri Jun 7 2024 .SYNOPSIS... Probability of light precipitation will increase late this morning north of Pittsburgh with passing shortwave. Below average temperatures are also expected into late Saturday. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... KEY MESSAGES: - Pockets of river valley fog will continue to develop early this morning east of Pittsburgh. - Probability of rain shower activity increases after day break north of Pittsburgh with a passing shortwave. - Areas north of I-80 may observe a few thunderstorms; small hail may develop. - Confidence is high that rainfall total amounts through Friday evening will be less than 0.25 inches. -------------------------------------------------------------- A passing surface trough is created enough lift early this morning to create a few stray showers across the region. Probability of precipitation decreases below 10 percent just before 3am. With noted remnant moisture, light winds, and some breaks in the clouds, river valley fog is noted northeast of Pittsburgh on Nighttime Microphysics GOES-16 satellite. However, confidence is high that fog will not be an issue during the early morning commute with passing clouds from the northeast with a new shortwave. Rain showers probabilities increase after 10am north of Pittsburgh with a passing shortwave and will likely continue into the late evening. Hi-Res model soundings suggest pockets of 50J/kg to 150J/kg low-level instability during peak heating. Therefore, a few updrafts may lead to thunderstorm activity. With a low freezing level (7kft to 8kft) and storm tops projected near 10kft to 11kft, a few cell may produce small hail. With rainfall activity being sporadic, low PWATs, and the loss of a well- defined warm cloud layer, rainfall totals will be range between a trace to 0.25 inches across the region; higher amounts mainly focused near I-80. High temperatures will range from mid-70s to mid-60s Friday afternoon. The probability of higher temperatures will likely be south of I-70, where clouds and precipitation will be heavily absent for a large portion of the day. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... KEY MESSAGES: - Precipitation chances will diminish late evening. - Dry, quiet, and cool weather is anticipated Friday night into Saturday morning with building high pressure from the west but prevailing northwest flow aloft. - Near-normal temperatures return Saturday afternoon. ------------------------------------------------------------------- An elongated trough over the Ohio River Valley will continue to advance cooler temperatures into the region Friday evening into Friday night. With clouds gradually clearing under the loss of diurnal heating and precipitation chances diminishing, temperatures will likely trend below average with radiational cooling and 850mb temps falling from 9C to 6C just before dawn. Ridging to the west suggest a dry and quiet Saturday and the return of near-normal temperatures A shift from west to southwest flow will likely return warm, moist conditions to the region Saturday night. However, temperature will likely still range near the climatological norm. && .LONG TERM /SUNDAY THROUGH THURSDAY/... KEY MESSAGES: - A passing cold front will return rain chances to the region early Sunday. - Cool temperatures to start should warm next week. - Hot conditions may develop late week with a noted ridge in long range models. ------------------------------------------------------------------- Convection returns early Sunday morning as a low pressure ejects out of the Plains and quickly passes into the Ohio River Valley. A few stray showers may evolve ahead a cold front, but Hi-Res model suggest shower activity confided to the boundary. In the wake of the cold front, expected clouds clearing and temperatures recovering to near just slightly below average. A strong ridge out of the Dakotas will continue to stream cool, northerly flow into the region Monday into Tuesday. If the sky remains cloud free, temperatures have the chance (NBM suggesting 40% to 60%) to fall below 50 degrees north of Pittsburgh and along the ridges. Precipitation chances remain low (less than 30%) Monday through Wednesday given long range uncertainty of a developing disturbance. Long range models are suggesting a pattern shift (June 13th- June 15th) as a ridge axis builds and returns warm conditions to the region. The NBM50th percentile is suggesting hot conditions Thursday into Friday as temperatures range in the upper-80s to low-90s. && .AVIATION /10Z FRIDAY THROUGH TUESDAY/... VFR conditions are expected through the TAF period. Areas of mid level clouds will cross the region this morning, rotating around an upper low centered across Ontario and the Great Lakes region. Model soundings and the CU rule indicate a broken diurnal cumulus layer will develop this morning as convective temperatures are reached, and continue through the day. Scattered showers are expected, mainly north of PIT, with that area in closer proximity to the low, and more favorable moisture. An isolated thunderstorm is also possible, though chances remain too low for inclusion in the TAF at this time. A sufficiently tight pressure gradient, and mixing, will result in west wind gusting to 25kt during the daylight hours today. Clouds should gradually decrease through this evening as temperatures fall below convective thresholds. Wind will also diminish with decreased mixing. .Outlook... Periodic restrictions and scattered showers are then expected through Monday as a slow moving upper low persists across the Great Lakes region. VFR should return Tuesday under high pressure. && .PBZ WATCHES/WARNINGS/ADVISORIES... PA...None. OH...None. WV...None. && $$ SYNOPSIS...Hefferan NEAR TERM...Hefferan SHORT TERM...Hefferan LONG TERM...Hefferan AVIATION...WM