textproduct: State College

WHAT HAS CHANGED

Decreased chc for SHRA/TSRA and removed mention of SVR TSRA for late this afternoon and evening.

KEY MESSAGES

1) Heat advisory in effect across the Lower Susq Valley and adjacent Scent PA through early this evening. Relief should be here for Sat.

2) A few fast-moving and generally low-topped TSRA are expected to flare up late this afternoon across the Eastern third of the CWA, with some producing brief gusty winds.

3) More storms will move into PA Sunday afternoon.

DISCUSSION

KEY MESSAGE 1: Heat advisory in effect across the Lower Susq Valley and adjacent Scent PA through early this evening. Relief should be here for Sat

As expected for many days, the heat and humidity will remain high through the daylight hours today over the SE. Overall, there are just minor adjustments to the temps/dewpoints for this afternoon.

The passage of a cold front late today/tonight will usher in lower dewpoint air and make it feel much less muggy on Sat. Afternoon RH in the 35-45% range will feel refreshing after a couple of very humid days. Temps will still be hot, getting into the 80s and perhaps near 90F Sat.

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KEY MESSAGE 2: A few fast-moving and generally low-topped TSRA are expected to flare up late this afternoon across the Eastern third of the CWA, with some producing brief gusty winds.

LLVL flow is broadly diffluent across much of the CWA with weak, neg llvl theta-E advection ahead of a cold front helping to negate much in the way of deep convection this afternoon. Furthermore, showers that developed across the Laurel Highlands and Wcent Mtns have dissipated as they moved into the enhanced llvl downsloping along the eastern edge of the Alleghenies.

Some development of a few taller showers and brief TSRA is still possible near and to the east of the RT 15 corridor, approx from KELM to KIPT and KTHV, but any threat of strong/damaging wind gusts has greatly diminished in this aforementioned unfavorable environment for deep convection.

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KEY MESSAGE 3: More storms will move into PA Sunday afternoon.

After the drier Sat, the flow backs and the more-southerly flow brings more-humid air back into PA. The mugginess will be noticed the most in the SE, with the Td just nearing 60F in the aftn. A very narrow jet buckles just a little and provides sufficient dynamics for another afternoon and evening round of severe thunderstorms. Arrival looks mid-late aftn NW with the storms crossing the CWA and exiting to the SE by 10-11PM. Some storms are possible out ahead of the front associated with the upper dynamics. The next visit from organized storms will likely not be until at least mid week (Thurs).

AVIATION /18Z FRIDAY THROUGH WEDNESDAY/

Drying, westerly downslope flow and broad llvl diffluent flow will prevent much coverage of otherwise fast moving showers and maybe a brief TSRA to the east of a KIPT to KSEG and KTHV line through 00Z Sat.

Have some VCSH in most of the TAFS later this afternoon, but even that convective development is looking less likely attm.

Otherwise, look for essentially VFR conditions to prevail late this afternoon right through Saturday.

A break on Saturday, but a stronger cold front on Sunday will bring the potential for more strong storms on Sunday.

Outlook...

Saturday...Mainly VFR.

Sunday...VFR favored early, with restrictions possible as FROPA brings chance of -SHRA/-TSRA later in the day.

Monday...Additional scattered -SHRA and associated restrictions possible.

Tuesday...Still a slight chance of showers and storms.

CTP WATCHES/WARNINGS/ADVISORIES

Heat Advisory until 8 PM EDT this evening for PAZ036-057-059- 063>066.