textproduct: State College

WHAT HAS CHANGED

* Minor changes to capture near term trends.

KEY MESSAGES

1) Warmer and more humidity during the second half of the week

2) Showers with strong to severe thunderstorms are expected for Thursday

DISCUSSION

KEY MESSAGE 1: Warmer and more humidity during the second half of the week.

930 PM Update... Low clouds pretty much gone with only high clouds streaming overhead. This should remain the same overnight. Without the low clouds, we will have some fog form overnight, mainly in the valleys. Dewpoint depressions already down to 2 at BFD, 1 at SEG and 1 at THV as they race each other to the bottom of the temperature rankings.

Previous discussion... Cooler temperatures through the middle of the week associated with a trough will give way to increasing humidity and warmer temperatures starting Wednesday afternoon. Increased temperatures and humidity will last through the start of next week.

Temperatures from earlier in the week in the 70s will warm to the upper 70s to mid 80s later in the week and into the weekend. Southerly return flow on the backside of a departing sfc high will help induce WAA and start to push increased moisture into the region. A passing warm front later Wednesday into Thursday will further increase temperatures and moisture across the area as the warm sector of a passing sfc low becomes established over the region. The cold front associated with the system will cross the area late Thursday into Friday morning. A drop in temperatures by a few degrees for Friday/Saturday will be possible behind the front. But temperatures and humidity will rebound and increase once again.

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KEY MESSAGE 2: Showers with strong to severe thunderstorms are expected for Thursday.

A pre-frontal trough tracking across the area ahead of the approaching cold front will cross the area during the afternoon hours. Currently the outlook from SPC is for a Marginal Risk for severe thunderstorms across the entire area. Current guidance brings somewhat favorable shear values of around 30 knots along with instability of around 1,000-1,500 J/kg. Uncertainty among guidance for the amount of cloud cover still remains as of the most recent model runs. Damaging winds with a lower chance for hail remains the primary hazard.

Increased PWat values to around 1.50" will also help increase the potential for heavy rainfall with thunderstorms that develop. The eastern half of the area still remain in a Marginal Risk for excessive runoff from WPC.

Thursday night continues to look poor for lunar eclipse viewing (around midnight local), especially for the eastern half of PA. Clouds and showers may not clear off by that time for the east. But, there is a chance for the west to begin to clear out. However, low clouds may also start to form in the mountains. So, the outlook for a clear or partly cloudy sky is not great.

AVIATION /01Z WEDNESDAY THROUGH SUNDAY/

Mainly clear skies and light winds will allow for patchy valley fog to form tonight over north-central PA. IFR restrictions appear most likely at BFD and IPT, though AOO and UNV may also see impacts from fog. VFR conditions will return by 14Z and will continue through the rest of the day under partly cloudy skies. Winds will be out of the south at 5 to 10 knots.

Outlook...

Thu...Restrictions possible in scattered afternoon showers and storms.

Fri...Still a slight chance of a shower, VFR otherwise.

Sat-Sun...Clearing conditions, VFR favored.

CTP WATCHES/WARNINGS/ADVISORIES

None.