Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 261716 AFDCTP Area Forecast Discussion National Weather Service State College PA 116 PM EDT Wed Apr 26 2017 .SYNOPSIS... A moist east-northeast inflow from the Atlantic Ocean will provide a cloudy and misty start today, followed by clearing through the afternoon. A few strong to severe storms are possible across the Northwest Alleghenies Thursday afternoon and evening. Warmer temperatures are expected through the end of the week. && .NEAR TERM /THROUGH TONIGHT/...
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We can see some funny blue stuff above the stratocumulus clouds locally. The GOES-16 0.64 channel shows most of the high clouds are in our easternmost areas and points east. Still some low clouds trapped in the valleys but mainly just strato-cu. The clouds will slowly erode and the temperatures will slowly climb this afternoon. Most areas should approach if not top 70F. The extreme southeast will likely be the last area to see the sun so they may not quite get to 70F in some locations. One of those days where northwestern PA will be warmer than our southeastern areas. Enjoy the late afternoon and evening pleasant weather. Due to weak flow and increasing moisture there could be some patchy fog. But a relatively warm overnight.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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Nice start to the day Thursday and it should be a warm day. Many areas will top 80F. The POP, CAPE, and PWAT fields all suggest a front approaches from the west in the afternoon. Noted the 12Z GFS is slower and our superblend is drier than previous runs. No real QPF in our region until around 2100 UTC and by 0000 UTC it gets to central PA and dies. The GEFS is not in yet. Clearly any showers/thunderstorms will most likely be in the late afternoon or evening hours. Only modest CAPE where the LLJ is the strongest. In the 600-900JKG-1 range. Better CAPE in some models/members to southeast where there is less lift and weaker winds. The front is moving into a strong ridge and it is a bit moisture starved. Overnight Thursday into Friday showers end or die out in central areas. A bit cooler and drier overnight Friday into Friday AM. The PW is normal to below normal and the 850 hPa temps are closer to normal to a tad above normal. There is no CAPE to speak of. Friday looks potentially like a really nice warm late April day.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/... Model and ensemble guidance remained in good agreement with large scale pattern amplification this period with a vigorous closed H5 low ejecting northeast from the southern Rockies into the upper Great Lakes/Canada and deep surface cyclone expected to lift out of the MS Valley. Meanwhile, an anomalous upper ridge centered over the Southeast U.S./western Atlantic will gradually weaken and shift east. The details of weekend forecast are still uncertain with rain risk likely focusing along/north of quasi-stationary frontal zone progged to shift south of PA by early Sunday before lifting back to the north as warm front. Therefore continued to utilize a NBM/ECENS/WPC blend for max/min temps and POPS which maintained good continuity with previous fcst. While unsettled with a period of rain likely at some point, the fcst does not look like a washout. Temperatures should remain above late- April climo but could be too warm/cool depending what side of the boundary you are on. Max POPS remain centered on Monday/May 1st as the aforementioned cold front crosses the Appalachians and continues toward the Atlantic seaboard. A severe weather threat may evolve downstream from the OH Valley into the Mid Atlantic, but at this time it is unclear whether instability will be sufficient to support severe storm risk. Temperatures will decline to near normal behind the cold front by next Tuesday May 2nd. && .AVIATION /17Z WEDNESDAY THROUGH SUNDAY/... Lots of clouds and low clouds around this AM. Some isolated bands of light rain too. Most areas are MVFR only patchy IR. Conditions should slowly improve later this morning and afternoon from west to east as the low to our east drifts away from us. Model RH profile support VFR conditions at BFD/JST by midday, while more gradual clearing takes place across the eastern half of the state during the afternoon. Poorest flying conditions will likely hang on the longest (perhaps until 16-17Z) across the Lower Susq Valley invof KMDT, KLNS and KMUI. Patch MVFR/IFR overnight expecting areas of fog. We also anticipate late afternoon/eve showers and thunderstorms over western areas spreading into eastern areas. Highest probability in the 21 UTC to 03 UTC range. Outlook... Thu...AM fog possible. Isolated PM tsra impacts possible west. Fri...No sig wx expected. Sat...Rain/low CIGs possible NW Mtns. Isolated tsra impacts possible southeast. Sun...Low CIGs possible east. Isolated PM tsra impacts possible west. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Grumm SHORT TERM...Grumm/Steinbugl LONG TERM...Steinbugl AVIATION...Grumm

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