textproduct: State College

WHAT HAS CHANGED

* An extreme cold watch has been issued for Somerset County from Saturday evening through Sunday afternoon.

KEY MESSAGES

1) Prolonged dangerous cold weather continues through the weekend, with wind exacerbating the cold on Sunday 2) Accumulating snow is possible Wednesday

DISCUSSION

KEY MESSAGE 1: Prolonged dangerous cold weather continues through the weekend, with wind exacerbating the cold on Sunday

The peak of the cold is upon us with record challenging minimum temperatures this morning and again tonight/AM Saturday. Mostly clear skies and diminishing winds tonight will support low temperatures below 0 for most if not all of central PA, with many locations taking a run at -10F or colder.

Saturday night into Sunday we will see wind gusts increase to 25-35 mph across the area as a result of the pressure gradient on the back side of an intensifying coastal storm. The increasing winds will limit the extent to which temperatures fall Saturday night, we'll still see wind chill values near -10F for most locations and potentially colder than -20F in the Laurel Highlands. Given this threat, an Extreme Cold Watch was issued for Somerset County for Saturday night into Sunday afternoon. Elsewhere, cold Weather Advisories are likely for Saturday night.

Temperatures will begin to moderate by Groundhog Day (Monday), but it will still be cold for this time of year with highs remaining below the freezing mark in most of central PA.

Be on the lookout for icicles and other large chunks snow and ice that might fall off rooftops as winds pick up into Sunday and temperatures rise into next week.

KEY MESSAGE 2: Accumulating snow is possible Wednesday

NBM/NBMv5 are signaling the chance for a stripe of light snow accumulation (1-3") on Wednesday Feb 4 with a clipper system. However, there is considerable spread in model guidance with the placement of this stripe of snow, with some solutions keeping central PA dry. We will continue to monitor and update the forecast as necessary.

AVIATION /19Z FRIDAY THROUGH WEDNESDAY/

The combination of NBM/GLAMP/HREF model guidance indicated high confidence in precipitation mentions being nixed in the 18Z TAF package with no precipitation expected across all of central Pennsylvania through 31/18Z. Restrictions remain most probable at BFD/JST through 31/18Z with IFR/MVFR conditions prevailing, respectively. Some periods of IFR are possible (~30-40%) at JST between 09-12Z, thus have outlined this potential in the 18Z TAF package. Elsewhere, VFR conditions are expected to prevail with high confidence. Some high-level cloud cover will be expected overnight between 00Z Sat and 12Z Sat) based on recent HREF model guidance. High confidence in the presence of some high- level clouds overnight further southeast, given current satellite trends coupled with recent model guidance.

Outlook...

Sun...Snow stays SE of the area, less than 10% snow at LNS. Dry conditions prevail area wide.

Mon...Dry conditions expected area wide.

Tue...Snow across N/W PA late, restrictions possible.

Wed...Snow continues overspreading the area, restrictions possible.

CLIMATE

Daily record-challenging temperatures possible to close out January:

01/30 Daily Record Minimum Max temps MDT: 13 in 1934 IPT: 12 in 1934 AOO: 11 in 1966 BFD: -1 in 1977 STC: 12 in 1977

01/30 Daily Record Minimum temps MDT: 2 in 1934 IPT: -6 in 1948 AOO: -3 in 2019 BFD: -14 in 1965 STC: -10 in 1977

01/31 Daily Record Minimum temps MDT: 2 in 1948 IPT: -14 in 1948 AOO: -4 in 2019 BFD: -13 in 2019 STC: -9 in 1948

State College has a very good shot of tying the second longest run (7) of consecutive days with max temp <= 20F (1/25-1/31). The last time this occurred was post-Christmas 2017 (12-28-2017 to 01-03-2018). The longest run of 10 days occurred in January 1893 from the 11th-20th.

Top 3 coldest last week/7 days of January (mean temp 1/24-1/31) for State College

CTP WATCHES/WARNINGS/ADVISORIES

Cold Weather Advisory from 7 PM this evening to 10 AM EST Saturday for PAZ004>006-010>012-018-019-025>028-034>037-041- 042-045-046-049>053-056>059-063>066. Cold Weather Advisory from 7 PM this evening to 11 AM EST Saturday for PAZ017-024-033. Extreme Cold Watch from Saturday evening through Sunday afternoon for PAZ033.