Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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796 FXUS61 KCTP 011123 AFDCTP Area Forecast Discussion National Weather Service State College PA 723 AM EDT Mon Jul 1 2024 .SYNOPSIS... A large high pressure system will build into the region today, followed by a dying cold front pushing in from the Great Lakes and stalling out over the area by the middle of next week. very warm and quite humid air will return for the second half of this week and last into the weekend. && .NEAR TERM /THROUGH TONIGHT/... High pressure (1026 mb or +2 Sigma) builds into the region today and tonight, before sliding to the Mid Atlantic Coast by Tuesday Evening. Much drier air advecting into the region early this morning via a light to moderately gusty (mid to upper teens - mph) NNW wind - with a rare touch of Lake Effect clouds and some very light rain/drizzle at times near the PA/NY border from the relatively shallow, yet still quite extensive strato cu clouds. Lake Erie water temps - 850 mb readings far exceed the required 13C needed for Lake Effect clouds and precip. This morning we have Lake Erie temps along the south shore averaging around 72F or 22C with 850 mb temps around 3-4C for a huge Lake/Air Delta T of 18-19C. Drier air will quickly mix down and erode the bkn-ovc clouds streaming south across the Northern Mtns and Laurel Highlands. Look for a mostly sunny to sunny late morning and afternoon with excellent visibility and PWAT Values ranging from about 0.5 of an inch in the West to 0.7 of an inch in the East. Winds will gradually diminish this afternoon and go nearly calm tonight as the center of high pressure (1025 mb or +2-3 sigma) become centered across Upstate NY and Northern PA. Strong radiational cooling early tonight will result in temps far exceeding air water delta Ts of 20F, which will lead to fairly widespread 1/2SM (or below) vsbys throughout the valleys of northern PA, with patchy 1-3Sm fog throughout the Central Valleys. Mins tonight will slide into the mid and upper 40s over the northern and western high terrain, and 50 to 55 respectively throughout the Central and Southern Valleys. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... Sunny and several degrees warmer on Tuesday into at least the first half of Wednesday, as upper level ridging builds over the state and the aforementioned surface high drifts east and just off the Mid Atlantic and Southern New England Coast. Day-day high temp increases will be 5 to 8 deg F, bringing us back to near or slightly above normal in the high temperature category on Tuesday. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... An Upper Level Ridge will drift east form the Central US and help to maintain fairly good amplification until Wednesday night/Thursday when a weakening shortwave passes well north of PA late Wed into Thursday and causes heights to sag up to a few DAM. The dying cold front is likely to sag into the state Thursday and stall out in the vicinity of PA through Friday. Falling heights/surging low level moisture ahead of the front could support scattered convection as early as Wednesday afternoon over the northwest half of PA. However, a better chance of showers/tsra areawide will come with the arrival of the front Thu into Friday. Early best guess of late week rainfall based on ensemble plumes ranges from 0.25 to 0.75 inches, with the highest amounts over the N Mtns and least in the south. Heat and humidity should peak ahead of the front Wed-Thu. Ensemble mean 850mb temps surging to near 20C indicate max temps could reach the low to perhaps mid 90s in the Lower Susq Valley Thursday, with high humidity pushing heat indices into the mid and upper 90s. Ensemble plumes suggest slightly cooler daytime temps late in the week, due to more clouds and scattered mainly afternoon and early evening showers and TSRA. However, high pwats in the vicinity of the stalling front should result in warm and humid days followed by muggy nights and above normal min temps the entire second half of this week. Models begin to diverge as we head into the weekend. Most guidance suggests that rain chances stick around through at least Saturday as another cold front approaches the area. && .AVIATION /11Z MONDAY THROUGH FRIDAY/... MVFR cigs persist over portions of central PA with residual moisture trapped beneath a low level inversion. Mixing of much drier air aloft should cause any early stratocu to dissipate by mid- late morning, with widespread VFR conditions expected the rest of the day. A fairly tight pressure gradient should result in gusty north winds for much of the day with gusts in the 20-25kt range for most of the region. Expect winds to diminish toward evening, as the center of the high pressure system pushes into PA. Outlook... Tue...Patchy AM valley fog N Mtns. Wed...Evening tsra impacts possible NW Mtns. Thu...AM low cigs possible W Mtns. Sct PM tsra impacts possible. Fri...Sct tsra impacts possible, mainly PM. && .CLIMATE... June 2024 was the warmest June on record for Bradford with a mean temperature of 66.6F, breaking the old record of 65.8F set in 2021. June 2024 was the 3rd warmest June on record for Harrisburg with a mean temperature of 76.0F. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert SHORT TERM...Lambert/Dangelo LONG TERM...Lambert/Bauco AVIATION...Fitzgerald/Colbert CLIMATE...Colbert