textproduct: State College

WHAT HAS CHANGED

Level 2/5 severe T-storm risk expanded over the southern tier of central PA for this afternoon and evening

KEY MESSAGES

1) Scattered severe thunderstorms with locally heavy rainfall are possible across the southern tier/third of central PA this afternoon and evening

DISCUSSION

KEY MESSAGE 1: Scattered severe thunderstorms with locally heavy rainfall possible across the southern tier/third of central PA this afternoon and evening

Our focus this afternoon is on the southern half of the forecast area as a warm front lifts northward into Pennsylvania. Sfc dewpoints are projected to surge into the upper 60s to the south of the front where some cloud breaks should allow for at least modest destabilization. The moderately sheared and conditionally moist/unstable convective environment should promote scattered t-storm ignition into peak diurnal heating. The initial storm development is expected to evolve into forward propagating clusters with a strong to locally damaging wind threat. As convection intercepts the northward moving warm front over the southern tier of CPA, locally backed flow and more favorable low level shear may support the development of at least transient supercells with some tornado potential. SPC has expanded the level 2/5 slight risk to include the entire southern tier/third of CPA (areas near and south of US-22) along with corresponding severe wind and 2% tornado probs.

Heavy rainfall will also be a concern with pwat values between 1.5 and 2 inches. This is around the 95th percentile for this time of year and would support intense rain rates perhaps as high as 2-3"/hr. A warm cloud depth in excess of 11,000 feet and tall, skinny CAPE profiles also support a heavy rain signal. WPC has maintained a level 2/4 slight risk for excessive rainfall (ERO) over roughly the southern third of the forecast area where isolated instances of flash flooding will be possible, particularly in training/repeat storms over urban areas. The two limiting factors going against a more considerable flash flood threat are the ongoing dryness/drought conditions focused over the LSV and fairly progressive storm motions.

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Drier conditions are expected for the middle of the week as high pressure builds into Pennsylvania, though there is an increasing signal for light rain to hang around for much of the day on Tuesday across eastern PA as a wave of low pressure develops along a cold front to our southeast. A slight warming trend is expected, with high temperatures expected to be in the 70s and low 80s through the end of the week. An upper level disturbance moving through the region on Thursday and Friday will bring the next chance for showers and thunderstorms to Central PA, though there are still some timing differences in the models as to when rain will be most likely.

Temperatures continue to warm up into the weekend, with most of the area expected to see highs in the 80s by Sunday. A major pattern change upstream over the Pacific/Intermountain West this weekend could spell a return of more typical hot and humid conditions to close out June and begin July.

AVIATION /00Z TUESDAY THROUGH SATURDAY/

Surface winds holding from the north early this evening helping keep the risk of storms mainly south of central PA.

Still have to watch the overall situation over the next few hours, as some models crank up the showers later tonight.

Overall the main issue will be a wide range of conditions overnight with low clouds and fog in many spots expected.

Conditions should improve later Tuesday morning into Tuesday aft.

Outlook...

Wed...Mainly VFR, dry conditions expected.

Thu...Restrictions possible in another round of showers and storms late.

Fri-Sat...Restrictions possible in additional showers and storms.

CLIMATE

5th driest June 2026 (MTD) on record (of 132 years) at Williamsport with total monthly precip 0.73"

9th warmest average high temperature of 84.4 degrees at Harrisburg for June 2026 (MTD) on record (of 138 years) 10th driest June 2026 (MTD) on record at Harrisburg with total monthly precip of 0.58"

CTP WATCHES/WARNINGS/ADVISORIES

None.