textproduct: State College

WHAT HAS CHANGED

* Continued to increase wind gusts across the Laurels, higher confidence in Advisory-level winds. * Little change with respect to the severe threat through this afternoon.

KEY MESSAGES

1) Marginal severe risk through this afternoon across all of central Pennsylvania with damaging winds being the main hazard.

2) Windy conditions expected today, with highest wind gusts across the Laurels where a Wind Advisory remains in effect.

DISCUSSION

KEY MESSAGE 1: Marginal severe risk through this afternoon across all of central Pennsylvania with damaging winds being the main hazard.

Current radar presentation outlines showers across central Pennsylvania with the nearest threat for thunderstorms across southeastern Ohio, thus have nixed all thunderstorm mentions in the near-term through sunrise Thursday morning. Current forecast utilizes a HRRR/HREF blend as it appears NBM has been tracking too slow with respect to the preceding shower activity across all of Pennsylvania this morning. This blend also outlines slightly better timing windows for thunderstorm mentions across central Pennsylvania as the cold front approaches later this morning and through the afternoon hours. In fact, bulk of model guidance indicated much of central Pennsylvania will be dry by 18Z (2pm EDT) outside of some scattered showers as the cold front moves east of the region by the late evening hours.

Speaking of the cold front, this will bring the best chances for strong-to-severe thunderstorms throughout the morning and afternoon hours. There was quite a bit of shower activity compared to forecast this time yesterday, which could very likely mute the severe threat across the region; however, cannot ignore the current severe threat going on across southeastern Ohio that does show that there is favorable amount of shear in the atmosphere. Recent forecast does bring the northern end of this activity into the southern tier slightly after sunrise, and could see some severe threat in this region with recent hi-res model guidance indicating some slight breaks in the clouds. This has been highlighted in more recent HREF probabilities in severe wind gusts, that highlighted less than 10% with the 00Z run yesterday, but is now above 10% for portions of southeastern Pennsylvania. Not a super large increase, but a slight increase nonetheless. We do expect tornado potential (mentioned due to observed TORs coming out of SE OH as of 4:30AM EDT) to become less favorable as they approach central Pennsylvania given slightly less veering in 850mb winds. Further north, unidirectional wind profiles do promote some severe risk throughout the morning and early afternoon hours with damaging winds appearing to be the only threat.

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KEY MESSAGE 2: Windy conditions expected today, with highest wind gusts across the Laurels where a Wind Advisory remains in effect.

Anomalously strong surface low- pressure tracking through the Lower Great Lakes will result in very windy day (especially by June standards with near-record low MSLP) this afternoon. Recent forecast outlines widespread maximum wind gusts between 35-45 mph this afternoon, with relatively higher wind gusts pushing close to advisory criteria. The most recent NBM (QMD) 24-hour maximum wind gust continues to highlight all of central Pennsylvania reaching into the 35-45 mph range with portions of the Laurel Highlands reaching into to the 45-50 mph range. Given this prospect, continued with the Wind Advisory this cycle with no changes; however, could realistically see a short-fused expansion across the northwestern Alleghenies if observational trends deem that gusts will overperform compared to previous forecast that employs NBM 90th percentile wind gusts. It is of note, that this set-up is similar to what we might see in March with area of deep surface low pressure tracking across southern Canada; however, this time of year poses a slightly different hazard with fully leafed trees which could to a higher impact versus our more typical cold season wind events.

AVIATION /09Z THURSDAY THROUGH MONDAY/

Nice sunrise here at the office. Conditions are mainly VFR, with a mid level cloud deck. Showers mainly near the MD border, with perhaps a gusty wind.

Expect this activity to move along and be out of the area by late morning or early aft.

More showers and storms could from by early afternoon, but expect most of this activity to be across the far east and south.

Main issue will the gusty winds from late morning into this afternoon. Winds should weaken by or just after sunset.

Outlook...

Fri-Sat...VFR with no significant weather.

Sun...Showers and thunderstorms developing in the afternoon across the far west.

Mon...Restrictions possible with widespread showers and thunderstorms.

CTP WATCHES/WARNINGS/ADVISORIES

Wind Advisory until 6 PM EDT this evening for PAZ024-033-034.