textproduct: State College

WHAT HAS CHANGED

Added gusty wind potential for the convection this afternoon.

KEY MESSAGES

1) Brief thundershowers possible this afternoon and evening, with wind gusts over 40 mph possible in some of the thundershowers.

2) Widespread rain on Monday, with severe and flash flood risk nearby to our south and east.

DISCUSSION

KEY MESSAGE 1: Brief thundershowers possible this afternoon and evening, with wind gusts over 40 mph possible in some of the thundershowers.

Arrival of low amplitude mid/upper trough combined with weak diurnal buoyancy should allow isolated to scattered low-topped convection to develop this afternoon and evening. CAMS show thundershowers developing over the Allegheny Plateau tracking to the east southeast through the evening. Modestly enhanced west-northwest flow and steep low level lapse rates could support a localized strong wind gust (40-45 mph), but the overall magnitude of the threat appears too limited for damaging wind probs/level 1 SPC categorical (marginal) risk at this time.

For the majority of central PA it will be a partly to mostly sunny and pleasant start to the weekend with max temps (generally below historical averages) in the upper 60s NW to around 80F in the Lower Susquehanna Valley. Breezy at times also today with wind gusts 20-30 mph from the west/northwest.

Winds will diminish tonight with partial clearing and patchy fog into early Sunday morning. Weather conditions for Father's Day look fantastic with astronomical Summer officially starting at 4:24AM Sunday.

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KEY MESSAGE 2: Widespread rain on Monday, with severe and flash flood risk nearby to our south and east.

A wet start to the work week with widespread rain expected on Monday. The heaviest rainfall is most likely between 8AM and 8PM with storm totals in the 0.75-1.50" range. Current probs off the latest ensembles and National Blend indicate 50-80% probs for >1" across most of central PA. Flooding risk is low with greatest risk likely confined to urban areas where locally heavy or repeat downpours could cause some isolated runoff issues. The higher risk for both flash flooding and severe weather appears to be to the south and east (Maryland and far eastern PA) near the warm front and within the warm sector, so we will need to monitor whether those features trend to the north and west. Rain tapers off/ends Monday night. With high pressure building in behind the departing low, Tue and Wed are likely to be generally dry.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

VFR remains prevailing for the rest of the afternoon into the overnight. Showers and some thunderstorms have developed from a mid-level shortwave entering into the region. While these are fast moving, meaning any restrictions they bring shouldn't last, they do carry with them rain, possibility of thunder, elevated wind gusts, and brief visibility restrictions. Exact timing confidence wasn't high enough to warrant TEMPO groups. However the scattered nature of these storms lends confidence in brief -SHRA/-TSRA region wide (with confidence lowest in LNS and MDT).

Confidence in any -SHRA/-TSRA decreases overnight, with mostly calm conditions expected. Models have hinted at visibility restrictions developing at BFD, JST, and UNV but confidence isn't high enough to drop under 5SM yet. will reassess confidence after we see where the most rain has fallen that may provide necessary moisture for more restrictive fog.

Outlook...

Sun...Showers and thunderstorms developing in the afternoon/evening across the far west, and around or shortly after Midnight over the Central and Eastern portions of the state.

Mon...Restrictions possible with a few periods of rain/or showers and thunderstorms.

Tue...Lower chances of showers, mainly VFR.

Wed...Mainly VFR, watching for precipitation chances though in the evening/overnight

Thu...Restrictions possible in another round of daytime precipitation

CTP WATCHES/WARNINGS/ADVISORIES

Will assess in future TAFs when the models None.