textproduct: State College

WHAT HAS CHANGED

* Increased wind gusts by about 5-10 kts from previous values based on winds in the upper half of the well mixed layer for Monday.

KEY MESSAGES

1) Colder tonight after a taste of summer like weather.

2) Light snow likely across the northern tier Monday/Monday night.

3) Much colder first half of the week but warming up again at week's end.

DISCUSSION

KEY MESSAGE 1: Cold front now east of our area as of early evening.

A gust wind will follow across the Central Ridge and Valley Region of the state, while deepening cold air, upslope flow and the approach of a mid and upper level trough from the Ohio Valley brings persistent layered clouds and a trend toward increasing chcs for light rain/snow showers across the NW Mtns. The mixed precip will be changing to mainly snow showers after dark. Some light rain/snow showers could drift over the Laurel Highlands too through early tonight as the main mid/upper level trough axis moves through. As the temps in the clouds and at the sfc get colder, the precip will become frozen and have little time/altitude above freezing to melt on it's way to the ground. There could also be a little graupel in a shower or two if they can tap a little CAPE. These SHSN will last into the first half of the night. Just a dusting of an accumulation is expected, mainly along and N of Route 6.

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KEY MESSAGE 2: Light snow likely across the northern tier Monday/Monday night.

A Clipper-like system dives down from Central Canada and across the Great Lakes on Monday. It has meager moisture to drop on Central PA, but numerous SHSN expected in the northern tier. More sparse showers (mixed) will make it south of I-80. Sfc temps are expected to get into the 40-45F range in the nrn tier in the aftn on Mon, so the p-type may be a mix, too. The NAM does paint some meager CAPE in the NW, too. So, there could be a briefly heavier spot of precip/snow here and there. At this point, it doesn't look dynamic enough to make serious snow squalls. However, the forcing looks strongest later in the day and evening Monday as a short wave trough passes overhead. A couple of models show the SHSN dipping into the Laurels in the evening. The SHSN will linger all night and perhaps into Tuesday AM until the (broad) axis of the upper trough moves past the CWA. Overall, the accums could be an inch or so in the nrn tier and perhaps a dusting in the Laurels and Alleghenies. Wouldn't be surprised to see a dusting on the ridge tops around Happy Vally by Tuesday AM.

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KEY MESSAGE 3: Much colder the first half of the week but warming up again at week's end.

Tuesday MA mins will be cold enough for frost over all of the area, but wind of 10-15 G 20-25KT will keep that from happening. The cold pool will be deepest on Tuesday, limiting max temps to the freezing mark near the NY border and 45-50F in the srn cities. These numbers will be about 10-12F below normals.

Wednesday morning will be the coldest this week due to the center of the sfc high being right overhead. Morning mins will be well below freezing everywhere. Even the Lower Susq will get into the L-M20s. The start of the growing season (date of the normal last spring freeze) is not until the 11th there. So, we probably won't be issuing frost/freeze products for that morning. But, collaboration with our neighboring WFOs will weigh heavily on that decision.

It then warms up close to normals maxes on Wed as the sfc high slides to our E and S and the wind turns to come out of the S and we should be sunny. Thursday looks much warmer, jumping another 10-15F over Wed's numbers. PoPs stay pretty low as we warm up as the sfc high noses back into the Deep South. That will help to keep moisture from the Gulf from getting to us.

AVIATION /06Z MONDAY THROUGH FRIDAY/

Early March-like weather pattern expected over the next 36-48 hours with reinforcing surges of unseasonably cold air. This will promote an uptick in rain and snow shower activity through Tuesday before high pressure arrives Tuesday night into Wednesday. The result will be intermittent rounds of rain and snow showers with occasional drops in visibility to MVFR/IFR. BKN-OVC ceilings will be fairly stable in the low VFR to solid MVFR range. Timing of visibility drops are difficult at this point so opted to use prevailing VFR to MVFR -shra/-shsn for now across the western and central terminals (outside of KMDT/KLNS) with highest odds for more frequent IFR visibility restrictions in shsn at KBFD. Wind is also a little tricky to time with 20-30kt gusts from 290-320 likely fading some today and shifting more to a 270 degree component before increasing later tonight into Tuesday.

Outlook...

Wed-Thu...VFR.

Fri...Chance of rain showers especially in the western airspace.

CTP WATCHES/WARNINGS/ADVISORIES

None.