textproduct: State College

WHAT HAS CHANGED

*The flash flood and severe risk has diminished this evening, with the Flood Watch allowed to expire as of 8PM.

KEY MESSAGES

1) Unsettled pattern continues through the first half of the weekend, with some flash flooding and severe potential.

2) Trending warmer for the first half of the weekend, with above average temperatures expected by Wednesday.

DISCUSSION

KEY MESSAGE 1: Unsettled pattern continues through the first half of the weekend, with some flash flooding and severe potential.

The flash flood and severe threat for this evening have largely diminished, allowing the Flood Watch in effect across the southern tier to be expired as of 8PM EDT. Heavier rainfall today will bring an additional round of flash flooding concerns tomorrow with more rainfall in the forecast.

Recent runs of hi-res model guidance continues to indicate some potential for shower and storm development ahead of an approaching cold front. The main uncertainty based on models will be the coverage of showers/storms during the afternoon hours with the bulk of model guidance indicating increasing coverage by the late afternoon and into the evening hours across much of central Pennsylvania. HREF ensemble guidance depicts PWATs generally in the 1.50-1.75" range across northern and western halves of Pennsylvania with values reaching into the 1.75-2.00" range across southern and eastern halves of Pennsylvania. In terms of climatologically, this puts much of the area between the 75th and 90th percentile in PWAT values for July 10th, which outlines that storms will be be efficient rainfall makes and could bring localized rainfall values (based on HREF 6 hour PMMs) between 1-2" in areas where soils are already saturated with more recent heavy rainfall. After that, a few showers remain possible on Saturday across the southern half of the area as the cold front will be very slow to move to our south. Sunday looks like a much drier day as the front finally moves off to the south and a strong ridge develops over the middle of the country.

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KEY MESSAGE 2: Trending warmer for the first half of the weekend, with above average temperatures expected by Wednesday.

Drier conditions are expected to prevail for the first half of the week with the aforementioned strong ridge expected to develop over the middle of the country. Increasing heat is progged by LREF ensemble guidance across central Pennsylvania although there remains some uncertainty with respect to how warm temperatures and/or humidity get across the region. Current forecast of the latter half of the week outlines above average temperatures Wednesday and into the end of our forecast timeframe which matches with CPC's 6-10 Day Temperature Outlook that highlights odds tipping towards above average temperatures across all of Pennsylvania. Chances of rain begin to increase into the latter half of the weekend as temperatures and humidity increase; however, quite a bit of time to hone in on exact placement of showers/storms that will likely change as we approach that timeframe.

AVIATION /06Z FRIDAY THROUGH TUESDAY/

Mostly VFR ceilings are expected for tonight, with areas of mist/fog possible due to recent rainfall and ample moisture in place. Some showery activity is holding on that's looking to cause some restrictions at JST over the next few hours and possibly leave MVFR conditions in its wake. Higher confidence in overnight restrictions from mist/fog are over the Allegheny Plateau (KBFD) and portions of the Poconos & Lower Susquehanna Valley that saw the most rain (more so KLNS than KMDT), with patchier fog across the central mountain terminals (KJST/KAOO/KUNV/KIPT). A few showers may develop within this moist environment tonight, though sparse coverage (<30%) precludes widespread TAF inclusions at this time.

VFR is favored on Friday, though another shortwave moving across the Mid-Atlantic may bring intermittent visibility restrictions due to showers/thunderstorms. A weaker wave of showers and a few thunderstorms is expected to cross our southern/central (KJST/KAOO/KUNV/KMDT/KLNS) terminals during the morning & early afternoon, with lower confidence in lightning & restrictions from this activity. Higher confidence in scattered thunderstorms, visibility restrictions, and locally gusty winds will be from the activity that develops during the afternoon around KBFD, which will progress south and east across the Commonwealth into the evening. Have adjusted highest confidence in timing to current guidance's outlook. Convective activity will once again trend downward around sunset, with lower certainty with regards to impacts for KMDT/KLNS downstream of the initial storms.

Outlook...

Sat...Reduced chance and more limited coverage of PM showers/t-storm.

Sun-Tue...Mainly VFR/no sig wx.

CTP WATCHES/WARNINGS/ADVISORIES

None.