Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 190016 AFDCTP Area Forecast Discussion National Weather Service State College PA 816 PM EDT Mon Sep 18 2017 .SYNOPSIS... A persistent ridge of high pressure at the surface and aloft will maintain fair, warm and generally dry weather during the entire upcoming week, and likely through the weekend as well. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Satellite shows the fog and low clouds have mixed out out over all but my far sern counties where the marine layer is deeper and slower to dry/mix out. Radar shows a few small showers popping up over my western zones where higher PWATs and heating on the ridges are forcing some local convection. There is a pretty good wedge of dry air around 700mb so showers will remain squat, with most areas remaining dry. The overnight will be a carbon copy from the department of redundancy department with daytime showers fading early followed by fair skies then followed by developing valley fog and low clouds. Lows in the upper 50s to lower 60s will average around 10 deg above normal. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... Tuesday will once again begin with the locally dense valley fog, burning off to a partly-mostly sunny afternoon as the upper ridge axis continues to reside right over central PA. The western extent of the outer bands of showers associated with Hurricane Jose that will be east of the Delmarva coast will flirt with SERN zones where I painted chance POPs in the afternoon. With expected light rain and thicker cloud cover, temps will likely be suppressed a bit across that region of the CWA compared to recent days. Max temps elsewhere will continue to run 6-10F above normal for mid September. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... For much of this period, a 500 hPa ridge will dominate our weather. As Jose moves away to the NE, heights will rise and this should further dry us out for the second half of this week. The GEFS forecasts a closed 5880 m ridge over us with near +2 sigma above normal heights by Friday and Saturday which will translate to well above normal temps. Enjoy! && .AVIATION /00Z TUESDAY THROUGH SATURDAY/...
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The main concern overnight is the likelihood of low cigs and fog developing across the central part of the state in response to radiational cooling under high pressure ridge. LAMP and SREF guidance support the idea of IFR/LIFR conditions late tonight over the western airfields, including KBFD/KJST/KUNV/KAOO/KIPT. Confidence in significant (IFR) reductions is lower across the southeast airfields, including KMDT/KLNS, due to the possibility of a persistent northeast breeze which could preclude fog/low cloud development. Currently guidance puts the odds of IFR just below 50 pct at KMDT/KLNS. Improving conditions are expected during late morning Tuesday, as any low clouds/fog begin to lift. Model data and climatology support a high confidence of widespread VFR conditions by Tuesday afternoon. .Outlook... Wed-Sat...Patchy valley fog possible each morning.
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&& .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...La Corte NEAR TERM...La Corte SHORT TERM...La Corte LONG TERM...Lambert/Gartner AVIATION...Fitzgerald

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