


Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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
911 FXUS61 KCTP 180914 AFDCTP Area Forecast Discussion National Weather Service State College PA 514 AM EDT Sat Oct 18 2025 .SYNOPSIS... * Increasing clouds with light rain showers or sprinkles tonight into early Saturday morning over north central PA * Clouds break for p.m. sun with noticeably milder temperatures to start the weekend * The weekend ends wet/windy with gusty rain showers Sunday afternoon-Sunday night; trending breezy/cooler into Monday && .NEAR TERM /THROUGH TONIGHT/... Increasing deep layer warm advection and associated weak isentropic lift was leading to fairly extensive altocu and high-based stratocu across the bulk of the CWA early this morning. Isolated to scattered, brief and light rain showers were drifting ESE across mainly the northern half of PA, with most of them not heavy enough or lasting long enough to do much more than dampen the ground with 0.01-003 of an inch. The higher end amounts mentioned here will occur almost exclusively near the PA/ NY border. By 16-18Z today, thicker cirrus, then altocu clouds will drift to the Susq Valley and points east as small scale and relatively flat ridging moves over the Commonwealth and a region of subtle descent beneath the thermally indirect, right exit region of a 300-500 mb jet moves NE from the Ohio Valley. Temps will start today +10 to +15 degrees higher than Friday morning - in the mid 40s to around 50F. Increasing southerly flow today will create weak llvl temp advection and combine with the sunshine and mild start to boost max temps +7-15F higher vs. Friday into the mid 60s to low 70s respectively, from east to west across the CWA. These temps will be (+10-15F above climo along the Allegheny Plateau and Laurel Highlands). Look for variable amounts of mainly mid and high clouds tonight, with similar to slightly milder overnight lows compared to early Sat morning. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... Amplifying 500mb trough will take on a negative tilt as it lifts through the Great Lakes/Ohio Valley into the Northeast on Sunday. A deepening a surface low (sub-1000mb) associated with the upper trough will track through Michigan into eastern Canada toward James Bay. Strong southerly flow ahead of the low will transport Gulf moisture northward and support a modestly moist air mass into PA. A cold front trailing the seasonably strong sfc low is expected to sweep eastward and serve as a focus for one or more lines/bands of gusty rain showers (shallow convective frontal rain bands) Sunday afternoon through the first part of Sunday night. The setup is a common transition season low CAPE/high shear environment with potential for strong to locally damaging wind gusts along the convective lines/frontal bands. Periods of heavy rain are also possible, but given the progressive forward motion, we feel that that flooding risk is pretty low or on the nuisance side (drought conditions also a contributing factor). Primary risk would be in urban or residential areas particularly where leaves clog storm drains. In fact, WPC trimmed back the MRGL risk for Excessive Rain to the Western Mtns and Northern Tier of PA in our CWA, but SPC expanded the MRGL SVR risk area slightly more to the east to encompass all of CTP`s CWA. A tight pressure gradient and 3-6mb fall/rise couplet indicates gusty winds will continue behind the cold front as the llvl flow turns to the west. We adjusted NBM wind gusts higher to max out in the 30-40 mph range or below wind advisory criteria for now. This will be the first "windy" period this Fall with the potential to blow leaves and unsecured objects (Halloween decorations) around. Max temps top-out in the 65-75F range in most areas on Sunday with some locations possibly approaching 80F in the LSV. Expect a steady drop in temps across the western Alleghenies Sunday night with low temps -10F colder vs. Saturday night. && .LONG TERM /MONDAY THROUGH FRIDAY/... Breezy and cooler to start next week with rain showers exiting the area Monday night. Wind gusts in the 25-35 mph range are forecast during the day on Monday and will amplify the 24hr cool down/maxT change of -10 to -20 degrees vs. Sunday. After a brief dry period Monday night into Tuesday, the remainder of next week looks unsettled and quite showery (especially downwind of Lake Erie over NW PA and the western Alleghenies) under the influence of large scale upper level troughing and broad cyclonic flow. It`s conceivable that the the first flakes of the season may be found over the higher elevations along the Allegheny Front. I guess it`s that time of year... && .AVIATION /08Z SATURDAY THROUGH WEDNESDAY/... A shield of mid and high clouds crossing the Great Lakes will continue to move over the airspace overnight. Ultimately an overcast deck near 10,000ft AGL is anticipated over much of the region by sunrise Saturday. However, there is high confidence (>90%) in no restrictions to flight categories due to the increasing clouds. VFR conditions should prevail throughout this TAF package. Surface winds will be generally calm overnight as well. The only area that could see some concern would be over northwestern PA near BFD. Scattered rain will likely develop off the coast of Lake Erie late tonight, and a PROB30 group has been included with BFD`s TAF to reflect the isolated chance of rain over that airfield. Outlook... Sat...VFR. A few showers possible over northwest PA. Sun-Mon...Restrictions possible in SHRA. Low probability of a thunderstorm over northwest PA. Tue-Wed...Scattered showers possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert/Steinbugl NEAR TERM...Lambert/Steinbugl SHORT TERM...Lambert/Steinbugl LONG TERM...Steinbugl AVIATION...Gartner/Tyburski