textproduct: State College

WHAT HAS CHANGED

* Tweaked mins down just a hair for tonight

KEY MESSAGES

1) Pleasant, rain-free dry spell to start June. 2) Summer conditions return later in the week into the first weekend of June.

DISCUSSION

KEY MESSAGE 1: Pleasant, rain-free dry spell to start June.

Trend, low dewpoints, light wind, and cold night last night point to another chilly night. Not as cold (5F above), but still very chilly for June 1.

Prev...

A deep upper level low over eastern Canada will rotate more energy aloft across the region tonight into Monday. The coldest air around will be advected well south into the southeast states. For central PA, mainly looking at dry conditions through mid week. Dry air is advected southward across PA, as high pressure builds southward from central Ontario. A good setup for dry conditions.

Last night was a cold night across the region, see the PNS sent. While it is much warmer now than yesterday, still looking at low dewpoints. With less wind than last night, looking at the potential for isolated cold pockets, with some frost in these spots over the next 2 nights.

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KEY MESSAGE 2: Summer conditions return later in the week into the first weekend of June.

The combination of a large high pressure ridge to our west, and a low just off the NC coast will keep mainly dry weather across central PA into Friday.

More information below.

Early week East Coast upper trough/closed low near the OBX shifts eastward and allows upper ridge axis to translate downstream from the Upper Midwest through the Great Lakes. This pattern transition will deliver a noticeable warming trend for late week with summer conditions returning into the first weekend of June. Max temps climb above early June climo into the 75-85F range on Thursday followed by widespread 80-90F readings fcst Friday-Sunday. An approaching cold front impinging on a very warm and increasingly more humid airmass will favor an increasing chance for scattered showers/t-storms by Saturday.

AVIATION /01Z MONDAY THROUGH FRIDAY/

VFR prevails through the 00Z TAF period, with key messages being: post-frontal northerly breeze on Monday; isolated afternoon showers; and easterly wind shift + increasing cloud cover behind backdoor cold front (primarily after 00Z Tuesday).

A weak, dry cold front will move south across the Commonwealth tonight, bringing a light northerly wind shift and minimal impacts. Northerly winds of up to around 10 kts are expected Monday afternoon, with spotty gusts to 15-20 kts possible. Diurnal heating (0-3 km lapse rates to 8-9 C/km) and cool air aloft (700 mb temperatures around -5 C) will support an afternoon cumulus field (SCT/BKN at 5000-8000 ft) + a few isolated light showers. With that said, the lack of organized lifting mechanisms in place & prohibitively dry air aloft (RH <5% above 700 mb) limits shower coverage/certainty below 30%.

High pressure building in from the north will bring a backdoor cold front down the Northeastern Seaboard later on Monday, reaching the Lower Susquehanna Valley (KMDT/KLNS) by 23Z Monday - 03Z Tuesday & continuing to the Central Mountains (KIPT/KUNV/KAOO/KJST) later in the night. Easterly winds and BKN/OVC clouds will accompany this front, with ceiling restrictions to MVFR unlikely (10-20% chance, mainly after 00Z Tuesday).

Outlook...

Mon-Fri...VFR with no significant weather. Any showers that develop Mon/Tue will be light and spotty. Any fog very limited.

CTP WATCHES/WARNINGS/ADVISORIES

None.