textproduct: State College

WHAT HAS CHANGED

* A Wind Advisory has been issued for Friday into Friday night across the Laurel Highlands and NW Mountains

KEY MESSAGES

1) Cold air advection underway this morning with gusty winds and lingering precip mixing with or changing to snow.

2) A strong Clipper system will pass to our north on Friday resulting in strong winds Friday afternoon and evening.

2) A warm front on Sunday will bring warmer and more humid air that will linger into early Monday before a strong cold front brings a period of rain Monday followed by colder, drier air and gusty winds again late Monday into Tuesday.

DISCUSSION

KEY MESSAGE 1: Cold air advection underway this morning with gusty winds and lingering precip mixing with or changing to snow.

The cold front has pushed east of the CWA as of 6AM Thu. Temperatures now range from the mid 20s in the northwest mountains to around 50 in the Lower Susquehanna Valley. Wind gusts have generally been 25-35 kts, but notably MDT did gust to 46 kts at 550 AM. Winds will be strongest this morning and slowly weaken through the day.

As the upper trough transitions from positively tilted to neutral and ultimately negatively tilted through the day, an area of precip on the back side of the cold front will continue to fall over eastern zones. For much of this area, the precip will change from rain to snow by mid morning. By that point, dry air will also begin filtering in at the lowest few km, and precip will get lighter. The combination of decreasing precip rate and the ground starting off warm should prevent any snow from accumulating, but a thin slushy coating on car tops and grassy surfaces can not be completely ruled out in the Lower Susq.

KEY MESSAGE 2: A strong Clipper system will pass to our north on Friday resulting in strong winds Friday afternoon and evening.

The next system will be a potent Clipper moving across the Great Lakes on Friday. This will likely bring a band of rain and snow showers across mainly the north, but otherwise more of a wind producer than a precip maker. Given the pressure gradient, winds will be near 50 kts at 850 mb. Our position beneath the right exit region of the mid/upper jet will likely promote pushing strong winds down towards the ground. Wind gusts in the 40-50 kt range are possible Fri afternoon into Friday night.

A Wind Advisory has been issued for the Laurel Highlands and Northwest Mountains for late Fri morning through 2 AM Sat. This advisory may need to be expanded eastward to include at least the Lower Susquehanna Valley. Subsequent shifts will continue to evaluate this potential.

Wind chills drop into the teens and 20s Friday night into early Saturday, a big change from the recent warm weather.

KEY MESSAGE 3: A warm front on Sunday will bring warmer and more humid air that will linger into early Monday before a strong cold front brings a period of rain Monday followed by colder, drier air and gusty winds again late Monday into Tuesday.

Guidance favors a Great Lakes Cutter track for the next system Sunday into Monday. This would result in a corridor of warmer air pushing in ahead of the system, with highs rising back into the upper 40s and 50s Sunday, and perhaps even the low 60s to start the day Monday. Much colder air and strong gusty winds push back in behind the cold front later Monday with cold temps around through the middle of next week. Latest NBM guidance shows highs stuck in the 20s and 30s on Tuesday, some 15-20 degrees below average.

AVIATION /12Z THURSDAY THROUGH MONDAY/

A cold front will cross the area from NW to SE early this morning. It will become gusty, with sfc winds becoming NWerly by Thurs AM. A brief appearance of lake effect and upslope -SHSN is possible at BFD and JST overnight, and went with VCSH in TAFs. Both airfields should see cigs dip to IFR overnight.

It is not out of the question that MDT/LNS could even have some wet snowflakes mix in with the -RA Thurs AM following the frontal passage, but sfc temps there will be above freezing.

Otherwise, MVFR cigs should hang on across the western highlands on Thursday, with everyone else eventually becoming VFR.

Outlook...

Thu-Fri...Windy and colder. Scattered rain and snow showers, with restrictions possible.

Sat...Becoming VFR.

Sun...Rain and snow showers possible across the northern half of PA. Restrictions possible.

Mon...Cold frontal passage. Pre-frontal SHRA/TSRA with IFR possible. Then turning blustery and colder. Post-frontal IFR or low-MVFR cigs expected across the west.

CLIMATE

A record high temperature of 79 degrees was set at Harrisburg on Wed Mar 11. This breaks the old record of 76 degrees set in 2021.

Bradford also set a record high of 67 degrees on Wed, breaking the old record of 66 set in 1977.

A record rainfall of 1.53 inches was set at Johnstown on Wed Mar 11. This breaks the old record of 1.20 inches set in 1952.

CTP WATCHES/WARNINGS/ADVISORIES

Wind Advisory from 11 AM Friday to 2 AM EDT Saturday for PAZ004-010-017-018-024-025-033-034.