Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 250016 AFDCTP Area Forecast Discussion National Weather Service State College PA 816 PM EDT Mon Oct 24 2016 .SYNOPSIS... Northwesterly winds will continue tonight and Tuesday, occasionally producing light showers over the mountains. High pressure overhead on Wednesday morning will allow temperatures to near or drop below freezing over most of Central PA. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Moderately strong llvl pressure gradient across the region tonight will be compensated by areas of clearing to significantly reduce the mixing depth at times and keep sustained winds in the 5-10kt range in the Central valleys, and 10-15 kts across the Lower Susq Valley and Laurel Highlands. Gusts will be in the upper teens to lower 20kt range over the Laurels. Overnight low temps will be controlled by the cloud cover. Trouble is, that is a tough forecast. RH remains high in the LLVLs, but downsloping and some mixing due to still- strong gradient flow will duke it out for how much cloudiness exists overnight and where. Will keep the forecast very climo with mostly cloudy to the NW of IPT-UNV- AOO. The current partly cloudy skies should fill in with some stabilization this evening. Will maintain the forecast of mins close to freezing on the highest elevations, but m30s- m40s elsewhere. Of course, some showers will stream inland from Lake Erie all night reaching the NW mtns at times. Some of the showers may be mixed with snow, instead of plain rain as 925 mb wet bulb temps dip to around 0C later tonight. Snow accums are not expected due to warm ground and --precip. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... Tuesday looks very much like Monday just a few degs colder. The wind should start to slacken later in the day but may not go calm overnight. Temps again the trouble for Tues PM/Wed AM. In this case, the 5-10F temp drop from Mon PM to Tues PM will spell a moderate-high threat for freezing temps across the whole CWA, and could kill off the rest of the vegetation across the SE, ending the growing season. Have posted a freeze watch for that possibility. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... With tail end of CAA Wed morning and surface high pressure in place, could be a freeze ongoing to start the extended period. During the day, CAA comes to an end as weak progressive upper ridge moves through and low-level flow turns back to the S/SW. A compact low developing over the Midwest will already be knocking on our door late Wed night. Drier air remains in place over the east Wed night, but expect showers to work into the west overnight. With overrunning precip potentially falling into low dewpoint air, wetbulbs may fall enough to mix some snowflakes in at the onset over the northern mtns. Then, Thursday looks like a rainy day with QPF values of 0.50-1.00 likely northern half. Cool northwest flow Fri followed by subtle ridging within main flow Fri night. Though model guidance still somewhat divergent after that, the weekend continues to look unsettled as a series of shortwave troughs slide through. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... Moisture flowing off of Lk Erie will continue to produce a varying amount of stratocu across Central PA into Tuesday, with the most persistent cloudiness and lowest cigs across the higher terrain from KBFD south to KJST. Although widespread VFR conds noted at 23Z, model soundings suggest CIGs will dip a bit as the boundary layer cools/moistens overnight, with MVFR becoming likely at KBFD/KJST late tonight. The gusty wnw winds will abate a bit after sunset as the atmosphere cools/stabilizes, but winds still expected to remain in the 7-10KT range for most of the terminals. Tuesday should be similar to Monday, as the flow changes little in direction but does get a little lighter. Diurnal heating and resulting mixing within deepening boundary layer will cause cigs to rise during the day, with widespread VFR conds anticipated by midday. Outlook... Wed...Patchy AM fog possible. Thu...Rain/low cigs possible. Fri...AM showers/low cigs possible W Mtns. Sat...Showers/MVFR CIGS possible NW Mtns. && .CTP WATCHES/WARNINGS/ADVISORIES... Freeze Watch from late Tuesday night through Wednesday morning for PAZ026>028-035-036-045-046-049>053-056>059-063>066. && $$ SYNOPSIS...Dangelo/Lambert NEAR TERM...Dangelo/Lambert SHORT TERM...Dangelo LONG TERM...RXR AVIATION...Fitzgerald is the U.S. government's official web portal to all federal, state and local government web resources and services.