Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 060454 AFDCTP Area Forecast Discussion National Weather Service State College PA 1154 PM EST Tue Dec 5 2017 .SYNOPSIS... A cold front will move east of the area overnight. The weather will turn noticeably colder as a pattern change brings a prolonged period of winter chill. The below average temperatures and mainly dry weather will persist into next week. && .NEAR TERM /THROUGH WEDNESDAY/... Meso anal shows the cold front is moving quickly, and just moved east of Williamsport and east of the office here about an hour ago. Temps have fallen below freezing over my far NW zones, but radar shows no precip and satellite show skies have cleared, so the usual scenario of rain changing to snow before ending will not occur with this cold front. The cold front will be clearing my SERN zones during the wee hours of Wednesday. The HRRR suggests the entire CWA is dry by around 3AM. Lows will drop into the 20s over the north, and remain above freezing over the SE. These will still be above normal, but the trend over the next several days will be downward. && .SHORT TERM /WEDNESDAY NIGHT THROUGH 6 PM WEDNESDAY/... Only some non-threatening strato cu is possible in the Alleghenies on Wed. The sky should clear out nicely elsewhere. The dry air and subsidence will initially make it tough for post-frontal precip to form. The flow near the lakes will be more from the WSW, and this would keep any bands which can form later in the day up to our north. Will leave a tiny POP in the far NW corner of Warren Co Wed. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Global model and ensemble guidance remains in very good agreement on the maintenance of high latitude blocking pattern featuring an amplified ridge-trough configuration over the West Coast and eastern NOAM. The primary forecast issues will be embedded shortwaves and associated surface waves/fronts, which due to their scale and fast mean flow aloft may be difficult to resolve until the short range time frame. There is high confidence in a prolonged period of below average temperatures into mid-December with a reinforcing shot of arctic air possible next week. The cold pattern will bring opportunities for snow; lake-effect is inevitable mid-late week but should remain focused along the Lake Erie shore into southwest NY given mean west-southwest low level trajectory. One or more clipper systems are probable and likely offer the best shot for light snow. Finally, there appears to be multiple waves of low pressure lifting north along a western Atlantic front from late week into the early weekend timeframe, with guidance varying on specifics. There is a possibility one of these waves could clip the eastern part of the area with some light snow, but right now the mostly likely outcome is for precip to stay east of the area or off the coast. A reinforcing shot of arctic air is looking more likely next week along with a more favorable northwest flow lake-effect pattern. The core of the winter cold should grip the area during the second week of December with some signs of moderation during week 3. && .AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
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Light lingering showers continue to move through the southeast portion of central PA. However, cigs and vsbys continue to improve as only MVFR cigs persist at MDT and JST. These conditions should continue to improve overnight into tomorrow. The next concern is the gusty wind from the west, then to the northwest overnight into tomorrow. These winds should increase through the daytime hours tomorrow. VFR should dominate the pattern tomorrow though persistent winds with gusts upwards of 25mph through the daytime are possible. Outlook... Wed-Sat...No sig wx expected.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...Steinbugl LONG TERM...Steinbugl AVIATION...Ceru/Martin

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