textproduct: State College

WHAT HAS CHANGED

* Lowered dewpoints on Tues and Wed * Increased wind gusts on Tues

KEY MESSAGES

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

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

DISCUSSION

KEY MESSAGE 1: Light snow likely across the northern tier Monday/Monday night.

Cloud cover across the CWA will continue to thin and clear out this morning, but clouds upstream will be arriving and spreading across the area from W to E through the rest of the day.

The moisture-poor system moving in across the Great Lakes will generate numerous SHSN over the northern half of the state and in the Laurel Highlands. Dry air in the llvls will limit the QPF, too. Sfc temps are expected to get into the 40-45F range in the nrn tier in the aftn, so the p-type may be a mix, and melt any snow that initially lays down. Meager CAPE over the NW could generate a briefly heavier spot of precip/snow here and there. HREF members, GFS, and NAM all generate a heavier shower or two in the Laurels and perhaps into the central mountains. Temps should be a little milder than in the northern tier, but the very highest hill tops may get a thin coating tonight/Tues AM. Overall, the accums could be an inch or so in the nrn tier and perhaps a dusting in the Laurels and Alleghenies.

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KEY MESSAGE 2: Much colder the first half of the week but warming up again at week's end.

Tuesday morning mins will be cold enough for frost over all of the area, but wind of 10-15 G 20-25KT should keep that from happening. Still, a great portion of the CWA will be <=32F Tues AM. Tues will be the coldest day as the cold front associated with the system passes before or around sunrise and a secondary front should move across during the daytime. Wind will also pick up as the dry, heavy air moves in. Model profiles show that we may be able to mix down gusts into the 30s on the ridge tops and in the downslope of the Lower Susq, and 20s elsewhere. RH will dip to 30-40pct.

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 to about 5F below normal 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. Dry air will still be in place, and the RH will certainly drop into the 20s for everyone as the temperatures warm but dewpoints don't keep up. Thursday looks much warmer, jumping 8-15F over Wed's numbers (greatest gains will be over the NW). PoPs stay pretty low as the sfc high noses back into the Deep South. That will help to keep moisture from the Gulf from getting to us. Temps rise another 10F on Friday. Moisture makes it all the way around the periphery of the high on Fri, and a front dropping in from Canada could make a couple of SHRA in the NW. But, these may dry up before reaching S of the Turnpike and I-81.

AVIATION /07Z 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.