textproduct: State College

WHAT HAS CHANGED

No significant changes with this update.

KEY MESSAGES

1) Warmer and more humid temperature build starting during the second half of the week

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

DISCUSSION

KEY MESSAGE 1: Warmer and more humid temperature build starting during the second half of the week.

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 isolated 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.

AVIATION /18Z TUESDAY THROUGH SUNDAY/

Upper level low over southwestern Ontario will keep cool northwest flow flowing off of the Great Lakes today.

This afternoon could see some gusty winds with 15-20 knots at times, most likely in the early to mid-afternoon, along with an increase in VFR stratocumulus.

Isolated showers may linger in the northern tier over the next few hours, but coverage and intensity is expected to be low. Skies will gradually clear out this afternoon into the evening as the upper low pivots out to the northeast. This gives way to clearer skies tonight and calm winds into Wednesday morning. Model guidance hints at patchy morning fog building in tomorrow morning with signal strongest in the northern airfields. IFR to LIFR restrictions are possible with fog that develops. Once fog burns off in the morning, VFR conditions are expected through the end of the TAF period.

Outlook...

Wed...Patchy morning fog, otherwise mainly VFR conditions.

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

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

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

CTP WATCHES/WARNINGS/ADVISORIES

None.