Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 160710 AFDCTP Area Forecast Discussion National Weather Service State College PA 210 AM EST Fri Feb 16 2018 .SYNOPSIS... A complex frontal system will move through the region overnight and early Friday. Cooler and drier weather will move in for Friday before a new frontal system brings more inclement weather for late Saturday through early Sunday. && .NEAR TERM /UNTIL 6 AM THIS MORNING/...
-- Changed Discussion --
Mesonet reports close to 2 inches of rain have fallen since last evening from Southern Clearfield Co southward through the Laurel Highlands. This area will continue to be the focus for the heaviest rain early this morning, due to a plume of anomalous PWATS ascending the high terrain of southwest Pa. Latest HRRR supports up to an additional inch of rain over Cambria/Somerset counties between 06Z-12Z. With rainfall in this area already near FFG, have opted to issue a flood warning through dawn, with a flood advisory downwind (east) of there into the south central mountains. Min temps tonight will be very mild and in the 50s in the SE, but in the lower 30s in the far NW where an early morning cold FROPA will send temps tumbling just before sunrise.
-- End Changed Discussion --
&& .SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SATURDAY/...
-- Changed Discussion --
Models indicate cold front will push SE through the region early this morning. However, significantly drier/colder air won`t arrive until passage of a secondary cold front linked to shortwave tracking across the Grt Lks. Model indicate this boundary will reach the northwest counties by late am, the central part of the forecast area by early afternoon and late afternoon across the Lower Susq Valley. Will keep showers in the forecast until passage of secondary cold front. Model soundings and HREFV2 data indicates just enough cold air may arrive for a brief change to snow showers over the Alleghenies before precip shuts off. Don`t expect any accums except perhaps a coating over the highest ridges of Somerset Co. After a mild morning, expect readings to fall during late morning and afternoon under strong cold air advection. Arrival of drier air is likely to bring clearing skies by late in the day.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... Period starts off with high pressure moving quickly west to east across the state. Weak and fast moving low pressure center is forecast to develop over eastern NC Saturday afternoon, an move to off the NJ coast overnight into Sunday morning. This could bring a swath of 2-4 inches of snow to much of central counties with a little less to the north and a little more to the south and east. Of some concern is the air and ground temps at the start of pcpn...this may limit accumulations til sfc temps can cool off. System clears out quickly for Sunday with a mild pattern resuming next week with rounds of rain targeting the northwest 1/2 of the area. Temps will be back into the 50s and 60 or so by Tues and remain mild into mid- week. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... TAFS updated. Visibilities remain rather good...even with the rain. Earlier discussion below. 00Z TAFS sent. 00Z TAFS close to earlier package. Main thing was to add more detail later on Friday. A moist southwest flow ascending the Allegheny Mountains will result in persistent MVFR cigs at KBFD/KJST through dusk, This will be followed by quickly lowering cigs spreading across the region this evening, as an area of low pressure approaches from the midwest and tracks across Pennsylvania tonight, resulting in rain of varying intensity and deteriorating cigs/vsbys. Cold front moving faster now...than what models had several days ago. Expect clearing from northwest to southeast later on Friday. Some snow may occur on the back side of the cold front across the northwest. Outlook... Sat and Sat night...Snow spreading northeast across the state late Sat and continuing into early Sunday with widespread IFR and LIFR restrictions. Sun...Clearing. Mon and Tuesday...Periods of Rain/low cigs possible, especially NW Mtns. && .HYDROLOGY... PWATs climb to 30mm - nearly 5 standard deviations above normal. Upslope and prolonged time of rain will result in 2-3 inches of rain in the Laurels and 1-2 inches across the middle third of the area. The greatest threat for flooding exists in the Laurels, but some minor problems may crop up in the central mtns. At this point, not enough to worry about in the central mtns for a flood watch. Much of the snow is melting, but the pack is dense, now. 50 dewpoints and strong SW wind will help melt quite a significant amount away today and tonight in the W. Streamflows are already well above normal (>75th percentile) in the southern half of PA right now. So, the rain will be excessive, and flooding is almost likely in the Laurels. The WPC outlook of a SLGT risk of excessive rainfall matches up nicely with the area covered by the watch. && .EQUIPMENT... The radar is down with a malfunctioning motor. Techs are in the process of trying to install a replacement. && .CTP WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
Flood Watch through this evening for PAZ024-033.
-- End Changed Discussion --
&& $$ SYNOPSIS...La Corte NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald/Lambert LONG TERM...Dangelo/Gartner AVIATION...Martin HYDROLOGY... EQUIPMENT...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.