textproduct: State College

WHAT HAS CHANGED

* Increased cloud cover percentage early today and again late today and early tonight.

* Keeping a close eye on NBM guidance max temps (may be too warm) for next week. Included more topographic/elevation detail in the hourly and max temps for Monday and Tuesday which cools values across the Mtns by several deg F.

KEY MESSAGES

1) Significant summerlike temperature begins today and ramps up Sunday through early next week; highest temperatures of the year so far

DISCUSSION

KEY MESSAGE 1: Significant summerlike temperature begins today and ramps up Sunday through early next week; highest temperatures of the year so far.

After a cool start to May, a significant summerlike warmup is on the horizon, beginning today and peaking early next week. GEFS 925-850 neg temp anomalies this morning will rebound to near normal for this afternoon and tonight before reaching levels of around +1.5-2 St Deviations for Sunday and +2-3 sigma for Monday and Tuesday.

This large scale pattern shift should deliver a rather sudden warm surge with max temps both Monday and Tuesday projected to reach well into the 80s and even lower 90s.

Daily record highs may be challenged based on the current fcst Monday and Tuesday. Max temps were adjusted lower by a few degrees due to a known systematic bias correction issue identified in the NBM during the shoulder seasons.

There may be some potential heat risk considerations looming for early next week, mainly for Monday and Tuesday. This stems not only with the forecast high temperatures and increased humidity, but also from an acclimation perspective. The summer like heat isn't expected to last long with the next cold frontal system pushing through the region Wed and Wed night with showers and isolated to sctd TSRA.

This will be followed by another notable dip in temps (to near or slightly below normal values) next Thursday and Friday, along with a chance for a shower or afternoon thunderstorm.

AVIATION /07Z FRIDAY THROUGH TUESDAY/

Lingering low-level moisture beneath a closed low that is exiting the region will maintain primarily MVFR across the western/central terminals (KJST/KAOO/KUNV) through the morning, with IFR being favored at KBFD & VFR favored elsewhere during this timeframe. Subsidence in the wake of this low will result in low clouds scattering out west-to-east over the course of the day, with regionwide VFR by the late morning & afternoon hours. The pressure gradient between a high pressure nosing in from the Mid Atlantic & the departing low will support daytime NW winds around 10-15 kts with gusts up to around 20 kts, followed by winds diminishing in the evening.

Outlook...

Sat-Sat Night...VFR is likely much of the time, although brief restrictions are expected at BFD and less likely at JST/UNV/AOO/IPT due to isold/sct SHRA/TSRA.

Sun...Sct SHRA/TSRA NW, VFR elsewhere.

Mon...Low cigs/isold --SHRA poss, mainly S.

Tue...Sct SHRA W. Otherwise, no sig wx.

CLIMATE

Daily record max temperature for May 18-19:

5/18 5/19 Harrisburg 94 in 1962 95 in 1962 Williamsport 95 in 1962 96 in 1996 Altoona 91 in 1962/1996/2017 92 in 1996 Bradford 85 in 1962 85 in 1962 State College 92 in 1962 92 in 1934/1996

Please note: State College Co-operative observations are a 24-hour summary taken once per day around 7 AM (7AM-7AM). Therefore, a max temp occurring in the daylight or late in the day is usually reported in the _next_ day's observation. Also, the same min temp may be reported on two consecutive days if the min occurs at observation time.

CTP WATCHES/WARNINGS/ADVISORIES

None.