textproduct: State College

SYNOPSIS

* Lake effect snow showers will start to wane this evening, but may not go away over the northern tier until close to sunrise. * Brief periods of snow (Northern PA) and a wintry mix (Southern PA) are expected late Saturday Night and Sunday with light accumulations possible * A more significant/widespread winter storm is possible on Tuesday * Large scale pattern supports cold conditions into at least the first weekend in December

NEAR TERM /UNTIL 6 AM THIS MORNING/

SPS issued earlier until Midnight for portions of south central PA, given some potential for snow showers, tempertures below freezing, gusty winds and wet roads. Potential for squalls mainly limited now to the far north, where heavy bands of snow showers extend well inland from the lakes as of mid evening.

Temperatures came back up toward the low 30s earlier this evening at the office, but are now edging back down. A deep storm over eastern Canada will keep winds on the gusty side. Current winter weather products go to 06Z, might need to extend further out in time if bands hold together.

Earlier discussion below.

The closed low over QUE and it's surrounding trough will be sliding to the east tonight. The 1000-850 mean flow won't change much at all overnight, though, so the exit of LES SNSH is likely to be a little later than we'd like. They may last all night across the nrn tier. Model soundings for BFD keep the cloud depth at least 5kft with the middle to top of the cloud in the DGZ until nearly sunrise. So, our current expiration time on the headlines up north (06Z) may need to be adjusted. On the other hand, though, the inversion is lowering and the dewpoints aren't rising, so the SHSN may not be as intense as necessary to warrant keeping the headlines going. So, for now, we'll keep the exp time as is.

The wind and gusts do gradually diminish thru the night as high pressure starts to move in from the SW. Temps may dip close to 20F in lots of places by morning. The bigger urban areas will be more in the m20s.

SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/

Saturday will be the best day we will have for a while. Most of the day should be dry. Adjusted the POPS for late Saturday at the leading edge of the pcpn, to fit better with others. Overall a minor change in the northwest corner of our area.

Earlier discussion below.

The last vestiges of the lake effect clouds and any flurries should end early in the morning Sat. The upslope low deck in the west will start to diminish, but high and mid clouds close up any breaks of sun in the afternoon. The sun in the southeastern half of the CWA will last thru a good part of the day. Lift ahead of the next batch of precip will not hold precip until after dark Sat evening, and perhaps not until close to midnight, in the NW. The low center is well to our N and the fast SW flow will pull the precip across the region quickly. The majority of models and the meso ensembles all make very little precip for the SE third of the CWA on Sunday. What does manage to hit the ground there would likely be a mix in the morning or plain rain from late AM on as temps warm up thru the day. Light snow will be the predominant precip type for the northern mtns. The best QPF is in the NW, too. The first swipe at snow totals there could be near 3 inches in our NW 5-6 counties, and near 2" in the NE. But, that would be the worst of it as the air is very dry with little moisture coming in from the Gulf. Very little signal for freezing rain that lasts more than an hour, but it is worth mentioning inside the broader collection of "wintry mix."

LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/

Precipitation will quickly taper off from west to east late Sunday evening into early Monday, so most of Monday should be dry.

Complex low pressure over the southeast states on Tuesday will quickly race to the northeast. This may limit the pcpn some, but often we get the snow more from the inverted trough.

Expect things to taper off rather fast by early Wed.

A fair amount of model spread as one gets toward next weekend, other than to say, no real mild spells in store for the area anytime soon.

Earlier discussion below.

Unsettled weather will continue into early next week as cold air in the middle of the country sets up a strong baroclinic zone over the eastern US. High pressure in the Plains should keep cold air in place on the northern side of the precipitation shield from a wave of low pressure progged to move out of the Gulf. This system should move northeast around the base of the aforementioned high pressure system, bringing increasing moisture to the Mid-Atlantic Tuesday into Wednesday next week. It remains too early pin down details of timing, intensity, and precipitation type delineation, the first widespread plowable snowfall of the season is possible.

System at this time looks to be somewhat progressive with the lack of a strong area of high pressure to slow the advance of the system which will be a limiting factor in eventual snowfall totals across the area. Location of the low-pressure system still also have impact on where a transition zone from freezing precipitation to rainfall will be observed across the area and intensity of precipitation. GEFS and ECENS probabilities of 6"+ continue to outline low-end probabilities, thus no thoughts of any mentions outside of the HWO. Continue to monitor the forecast in the days ahead, especially if you have plans to travel.

High pressure will regain control of our weather in the wake of the aforementioned system for the middle to end of next week. Prevailing upper troughing brings high confidence in continued below normal temperatures and a chilly start to December.

AVIATION /06Z SATURDAY THROUGH WEDNESDAY/

Bands of snow showers will be across north central PA overnight. The main site to have snow showers will be BFD, and perhaps JST at times with the very weak activity over the southwest. A few flurries may get into AOO and UNV. Not expecting any snow for IPT, MDT, or LNS overnight.

I expect the activity to taper off during the day, with VFR conditions by later in the day.

Winds shift to the southeast Saturday night, as a warm front moves toward western PA. Any snow would be after 06Z Saturday, given current timing.

Outlook...

Sun...Light rain/wintry mix developing from west to east; restrictions possible. Precip may turn to rain across the south during the day.

Mon...Mixed/wintry precip likely early on. MVFR likely. IFR possible.

Tue...Snow possible, before a possible mix later in the day across the south. Restrictions possible.

Wed...Trending drier, lingering snow across NW PA.

CTP WATCHES/WARNINGS/ADVISORIES

Lake Effect Snow Warning until 1 AM EST early this morning for PAZ004>006. Winter Weather Advisory until 1 AM EST early this morning for PAZ010-011-037.