textproduct: State College

WHAT HAS CHANGED

* No significant changes to the fcst for the upcoming 48 hours. Maintained increasing heat and humidity for the latter half of this week.

KEY MESSAGES

1) Patchy fog is possible in sheltered valleys, mainly north, overnight as temperatures cool off into the 50s.

2) Low RHs

3) Warmth surges again later this week with dangerous heat possible Thursday and Friday.

DISCUSSION

KEY MESSAGE 1: Patchy fog is possible in sheltered valleys, mainly north, overnight as temperatures cool off into the 50s.

SFC ridge axis extending south-southwest into the Ohio Valley from a 1020 mb high center located over southern Quebec.

The light northerly flow across the CWA during the short overnight combined with and anomalously low PWAT values for early June will minimize the occurrence for any fog below 1/2SM late tonight/early Monday.

While the airmass is dry, the temps should be dipping to and perhaps below the crossover temps (mid-aftn dewpoints) in the lower elevations of the Allegheny Plateau. Otherwise mainly clear sky and light north to NE breeze, if any, will combine with the dewpoints in the low-mid 50s to give us a comfortable night.

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KEY MESSAGE 2: Low RHs

RH will dip into the upper 20s and 30s Mon, and 30s over the east on Tues. Paired with relatively light wind and the greened- up landscape, though, it should yield no elevated risk for rapid wildfire spread.

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KEY MESSAGE 3: Warmth surges again later this week with dangerous heat possible Thursday and Friday.

While the NBM max temps have inched lower by 1-4F for the next couple of days, the latter half of the week still looks hot. 90s should be widespread Thurs and Fri. The elevations of the Alleghenies will be the coolest spots, but the valleys there could also get to 90F. Heat Index/ApparentT values remain virtually unchanged for those two days.

The new/cooler temps T-W are likely due to the raised cloud cover and higher chc of precip vs prev guidance. Categorical (80%+) PoPs appear Tues night over the west as moisture increases and sct TSRA are expected. These shouldn't get too far to the east, perhaps staying W of UNV/AOO. Wed will hold widespread SHRA/TSRA over the bulk of the CWA as the upper ridge weakens and shortwaves (old MCSs) crest the ridge and meet up with the increasing moisture.

Only slight relief arrives Sat, but temps remain very warm/hot. The 6-10 and 8-14 day outlooks are for continued above normal temps (and precip). Above normal precip would help out the areas that continue to be in drought.

AVIATION /01Z MONDAY THROUGH FRIDAY/

Winds will continue to die down overnight and take on a more easterly character as high pressure builds to our east. The light winds and clearer skies will allow for enough radiational cooling for patchy fog to develop, most likely in the 08Z-12Z timeframe. While low lying valleys are the areas with greatest confidence in fog development, visibility restrictions due to fog/mist are possible at BFD and UNV. Confidence isn't high enough to introduce MVFR, or lower, restrictions into the TAFs, but should a more aggressive fog up solution be favored during the overnight model runs, it may have to be added in future TAFs.

As mentioned in the previous discussion, a backdoor cold front will move through our easternmost terminals (KIPT/KMDT/KLNS) Monday morning (09Z-12Z). It brings with it a chance of MVFR ceilings, but most model solutions look too scattered to introduce them into the TAFs. Cloud bases during the morning will be lowest at LNS and MDT in the 3-4kft range. Clouds continue to scatter during the afternoon and winds will increasingly turn more southerly as a high cirrus deck moves in from the west in the late afternoon/evening to the western terminals.

Outlook...

Mon-Tue...VFR favored outside of isolated morning fog. Restrictions possible in -SHRA/-TSRA late Tue.

Wed-Fri...Restrictions possible in -SHRA/-TSRA.

CTP WATCHES/WARNINGS/ADVISORIES

None.