textproduct: State College

WHAT HAS CHANGED

* Increased max wind gusts for Thursday

KEY MESSAGES

1) No change to marginal severe/heavy rain risk overnight through Thursday afternoon

2) Unusually windy by June standards Thursday

DISCUSSION

KEY MESSAGE 1: No change to marginal severe/heavy rain risk overnight through Thursday afternoon

HREF and REFS 3hr PMMs both indicate upstream convective activity in the Ohio Valley will likely weaken as it reaches NW PA late tonight. This suggests a rather low potential for severe wx and/or heavy rain impacting CPA.

Early day/leftover convection sliding to the southeast brings a reduced severe wx risk to much of CPA on Thursday with the strongest activity most likely to develop along a cold front between midday and late afternoon across the lower Susquehanna Valley or to the southeast of I-81. Very strong low level wind fields for this time of year will promote a isolated to scattered damaging wind threat. SPC made no changes to the convective outlook for Thursday with the 1730UTC update.

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KEY MESSAGE 2: Unusually windy by June standards Thursday

Anomalously strong -4SD (near record low MSLP) surface low- pressure tracking through the Lower Great Lakes will result in very windy day by June standards on Thursday with widespread gradient/non-thunderstorm wind gusts between 35-45 mph. Max wind gusts could approach advisory criteria in some areas. Fully leafed trees may also lead to a higher impact vs. more typical cold season wind events. We will continue to highlight wind impacts in the HWO with some considerations given to a NPW headline for this cycle.

AVIATION /18Z WEDNESDAY THROUGH MONDAY/

VFR conditions are expected through the rest of the day with scattered to broken clouds between 4000 and 5000 feet. Winds will be out of the southwest at 10 to 15 knots with gusts to 25 knots possible. Widely scattered showers will continue to pop up over the eastern half of PA through the rest of the afternoon, but most locations likely remain dry. The best chance for any showers will be at MDT and LNS.

Mid and high clouds increase overnight ahead of a warm front lifting northward through the region, and light rain will overspread Central PA from west to east after 00Z. A very strong low-level jet for this time of year will move through tonight, leading to a period of LLWS at nearly all TAF sites into the morning.

A weakening line of showers and thunderstorms is then expected to move through along a cold front, first reaching BFD and JST in the 08-09Z timeframe. This line should be east of all TAF sites by 15Z. PROB30s have been included at all TAF sites to provide some more specific timing for heavier showers and thunderstorms, but the timing may have to be adjusted as confidence increases. There is some potential for these showers and storms to mix down some of the very strong winds aloft, but confidence is low on this occurring.

Scattered showers will continue through the rest of the morning behind the front, but widespread rainfall is unlikely after 14Z. The bigger concern for Thursday will be strong westerly winds. Gusts to 30 knots appear possible at all TAF sites, with BFD, JST, AOO, and UNV, potentially seeing gusts as high as 40 knots.

Outlook...

Thu PM...Scattered showers and gusty winds.

Fri...Showers ending.

Sat...VFR with no significant weather.

Sun...Showers and thunderstorms developing in the afternoon.

Mon...Restrictions possible with showers and thunderstorms.

CTP WATCHES/WARNINGS/ADVISORIES

None.