textproduct: State College

WHAT HAS CHANGED

* No significant changes.

KEY MESSAGES

1) Showers/isolated t-storm likely near and southwest of US-322 this afternoon

2) Noticeably cooler start the last weekend of April with periods of rain tapering off early Sunday

3) More seasonable end to what has been one of the warmest April's on record

DISCUSSION

KEY MESSAGE 1: Showers/t-storm likely near and southwest of US-322 this afternoon

HREF/RRFS show rain showers or an isolated t-storm developing this afternoon within llvl convergence zone (located near or just to the SW of US-322) associated with a backdoor cold front. Any t-storm is expected to be non severe given weak instability and shear profiles. A couple of slow moving downpours are possible as PW values gradually tick higher through the evening to ~ 1 inch. Hires models signal a relative decrease in shower coverage into tonight with max POPS over the northern and western periphery of the CWA by 12Z Saturday.

KEY MESSAGE 2: Noticeably cooler start the last weekend of April with periods of rain tapering off early Sunday

Weak area of low pressure slides east-southeastward from the thumb of lower MI to the southern Delmarva/VA Tidewater region Saturday. Passage of upper level trough and moist east/southeast llvl flow will help support periods of rain into Saturday night with total QPF amounts generally in the 0.25-0.75" range. CAD pattern will result in a 24hr maxT change on the order of 15 to 20 degrees to the downside vs. Friday. Rainfall will be of the beneficial variety particularly across the far south central and southeastern zones were moderate /D1/ to severe /D2/ drought conditions exist. Rain ends in time to salvage the second half of the last weekend of April 2026. High pressure building in Sunday night could introduce a frost risk in some parts of the area early Monday morning.

KEY MESSAGE 3: More seasonable end to what has been one of the warmest April's on record

Most sites are tracking top 5-10 warmest April-to-date through the 23rd. The much above normal warmth is expected to fizzle out through month-end as the pattern shifts cooler on the margin with more seasonable days and nights near or slightly below the historical average heading into May.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

VFR is likely to prevail through 00Z Saturday with flight restrictions limited to SHRA across Central PA tomorrow morning & afternoon.

Clouds will increase between 02Z-07Z Friday as a shortwave approaches from the northwest, with conditions remaining dry through the night. An initial round of scattered showers is expected between 12Z-17Z Friday along a narrow NNW/SSE boundary over Central PA (closest to KBFD/KIPT/KUNV), where milder/moist air from the southwest meets & rises over cooler/drier air from the northeast. Most of these showers will move across the drier side of this boundary, with VFR favored for these showers given low-level dry air (T/Td spreads around 10 degrees C).

A second round of scattered showers will develop across this boundary in the afternoon (18Z-24Z), driven by instability developing on the mild/moist side (HREF mean SBCAPE around 500 J/kg). Visibility restrictions will be more likely with these showers given the diurnally driven instability in place, with brief gusty winds also possible given the inverted-V profile in place (primarily KJST/KAOO/KUNV). For our other sites, spottier shower coverage is expected due to greater distance from the frontal boundary & less moisture being available on the drier side, though visibility restrictions to 5-6SM are possible. Moreover, a few thundershowers may develop given the instability, though the low-topped nature of these showers (HRRR modeled cloud top temperatures warmer than -30 degrees C) precludes TSRA mentions at this time.

Outlook...

Sat-Sun..Periods of rain with MVFR to IFR conditions.

Mon...VFR likely.

Tue...VFR early, with restrictions west to east as ceilings lower and showers move in.

CTP WATCHES/WARNINGS/ADVISORIES

None.