textproduct: State College

WHAT HAS CHANGED

* Probability of a tornado increased over western PA from 2% to 5% with conditional intensity level 1

KEY MESSAGES

1) 1st severe thunderstorm risk of 2026 focused over western Pennsylvania later this afternoon/evening

2) Significant early springtime warm-up expected into Wednesday followed by late week cooling trend

DISCUSSION

KEY MESSAGE 1: 1st severe thunderstorm risk of 2026 focused over western Pennsylvania later this afternoon/evening

The first severe T-storm risk that includes a portion of CPA in 2026 remains on track for later this afternoon and evening. The primary threat area and greatest categorical risk (level 2 out of 5) will be focused from the Upper Ohio Valley into western PA with the eastern extent reaching the I-99 corridor. While it's possible that storms could extend farther to the east, the odds of them reaching severe limits drops off substantially given the anticipated low level stability associated with the persistent cool wedge that has been in place over east-central PA for the past few days.

The kinematic/wind shear profiles forecast over western PA (west of US-219) later today are quite strong for this time of year. In particular, the low level shear accentuated near or along a warm front could support a few supercells with attendant tornado risk in advance of a cold front reaching northwest OH by 00Z. SPC made a noteworthy and incrementally higher adjustment to the tornado probability (2% to 5%) and included a newly rolled-out conditional intensity level hatching within the 5% tor prob. For tornadoes, this essentially translates to IF a tornado occurs, it has greater-than-climo potential to reach EF2+ intensity. This helps to contextualize a reasonable max tornado intensity based on the environment and storm mode. Otherwise, a linear convective mode is favored with a potential line of strong to severe storms ahead of the aforementioned cold front capable of damaging winds.

KEY MESSAGE 2: Significant early springtime warm-up expected into Wednesday followed by late week cooling trend

Cool wedge pattern finally breaks down and allows for a significant springtime warming from Sunday into the middle of next week. Frontal showers exit the area Sunday morning with rain-free conditions likely holding into Tuesday. Dry and breezy conditions on Monday could lead to the first elevated risk of rapid wildfire spread for the year, especially across southeast PA where less rain is expected over the next 36 hours. Southwest flow builds by Tuesday, with a surge in temperatures and dewpoints anticipated. April to May- like max/min temps fcst +20-30 degrees above the historical average will challenge daily records in some areas Tue/Wed. Cold frontal passage Wed/Thu will bring some rain followed by gusty winds and a late week cooling trend back to near/slightly below normal climo.

AVIATION /14Z SATURDAY THROUGH WEDNESDAY/

Not a lot of change as of mid morning, cold air at the very lowest levels still in place for most of central PA. Main change was to cut back on showers through early afternoon, as most of the showers and isolated storms have been lifting northeast across the northwest corner of the state, i.e. BFD. Also added LLWS at IPT, given gusty easterly flow the next few hours.

Earlier discussion below.

Cold air damming across the ridge and valleys of central Pennsylvania is providing the anchor for IFR conditions overnight. Central forecast sites remain IFR, with some clearing and jumps to VFR at KJST and KBFD. An increasing low level flow ahead of a frontal boundary will keep low level windshear to the far western airfields through mid morning as it rides overtop the relatively colder air near the surface.

The cold frontal boundary will barge its way across the state through the afternoon and evening hours. Strong thunderstorms over western Pennsylvania early in the afternoon will diminish as they ride over top of the aforementioned low level cold air still generally trapped in the valleys over the central and east.

Enough wind and some mixing will help bring ceilings and visibility up to MVFR to VFR by late morning before a line of thunderstorms lowers both for a brief period through the afternoon and evening.

Outlook...

Sun...Trending towards VFR and breezy.

Mon...Restrictions possible as low-level moisture increases.

Tue...Restrictions possible in the morning due to low-level moisture. Showers later in the day.

Wed...Restrictions likely in showers.

CTP WATCHES/WARNINGS/ADVISORIES

Dense Fog Advisory until 10 AM EST this morning for PAZ058.