textproduct: State College

WHAT HAS CHANGED

* No major changes made to the forecast at this time.

KEY MESSAGES

1) Dry weather Friday and Saturday with warmer temperatures. Snow showers possible Saturday night into early Sunday.

2) We continue to watch for the potential of additional wintry weather early next week and rain into the middle of next week.

DISCUSSION

KEY MESSAGE 1:

Upper level trough across the Northeast US is rotating eastward today as a weak surface trough in the Mid Atlantic tracks east and northwest flow across the eastern Great Lakes keeps lake clouds just north of the PA/NY border. A more dominant surface high builds in tonight and tomorrow with rising heights aloft contributing to synoptic scale subsidence and mostly clear skies. As the long wave trough moves east and the next short wave drops into the central Canadian Plains the weak ridge in between will amplify over the Great Lakes as it moves into the Northeast. The air mass associated with the ridge will be noticeably warmer with 850mb temps 0 to +2 deg C...allowing surface temperatures on Friday to climb into the low to mid 40s across north-central PA and into the upper 40s and lower 50s in central and southern PA.

Temperatures are expected to remain mild overnight Friday into Saturday...only dropping into the lower to mid 30s. The relative warmth will persist on Saturday with afternoon highs into the mid to upper 40s north...and mid to upper 50s south.

A stronger amplification of the synoptic trough over central and eastern Canada will occur Saturday and eventually drop south Sat night. Colder air will arrive with this trough and bring temperatures back into the 20s and 30s, along with a low chance of snow showers late Sat night into Sunday morning. The best chance (30-50 pct) of snow will be across the northern tier of central PA. No significant/impactful snow is expected at this time.

KEY MESSAGE 2:

The long wave trough remains mostly in place across the region Sunday night into Monday night, but uncertainty arrives with the wave pattern to the south that may bring additional rounds of precipitation to the region. A couple waves move in from the central US and attempt to brush the southern fringes of the cold air mass during this time with some potential episodes of rain/snow, but there is still quite a bit of uncertainty regarding the north- south extent of these waves. There is high confidence in the overall pattern becoming warmer by the middle to latter part of next week. Several short waves may move across the region during this time as well, which would likely bring rain (rather than snow) to the region. Will need to monitor this potentially significant pattern shift as this could prove impactful to the break up of river ice and lead to an increased threat of ice jams.

AVIATION /18Z THURSDAY THROUGH TUESDAY/

Forecast terminals are expected to be VFR through the next 24 hours. High clouds continue to stream west to east across southern PA this afternoon due to a weak system passing by to the south. The chances for a light rain shower around KLNS and KMDT have decreased, restrictions are not expected at this time. Will still need to keep an eye on the development of a very shallow low-level inversion with calm winds early tomorrow morning at KLNS and KMDT. So, there is still the potential for a few low clouds or patchy fog in these areas prior to daybreak.

Outlook...

Fri-Sat...Dry conditions with VFR probable. Rain and snow showers and associated restrictions possible Sat. Night into early Sun.

Sun...Mainly VFR.

Monday...Snow showers possible and associated restrictions. Confidence is low but KJST, KAOO, KMDT and KLNS look to have the best chance at this time.

Tuesday...Another round of snow and/or rain is possible across much of central PA which could cause some vsby and cig restrictions. Confidence is low to medium.

CTP WATCHES/WARNINGS/ADVISORIES

None.