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
46
47
48
49
50
464 FXUS61 KCTP 050106 AFDCTP Area Forecast Discussion National Weather Service State College PA 906 PM EDT Sat May 4 2024 .SYNOPSIS... Cloudy skies with areas of light rain, drizzle and fog will persist throughout the weekend. High pressure slowly building eastward from the central Great Lakes will bring some drying and brightening to northern and central Pennsylvania by Monday and Tuesday, but the south will remain on the cloudy side with some showers. The pattern remains unsettled mid to late week with weather systems bringing rain chances Tuesday night into Wednesday, and Wednesday night into Thursday. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... Boundary layer convergence continues to ramp up this evening over central PA as 850 mb jet amplifies in rich deep layer moisture environment combined with easterly llvl maritime flow. This will continue to support widespread light rain and drizzle throughtout central PA through the overnight and keep temperatures within a few degrees of current readings through 12z Sunday morning. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/... Sunday will be unseasonably cool with slowly decreasing easterly flow from off of the western Atlantic, as we start to see an increasing southerly component in time. This will lead to a slight rebound in warmth over especially western/southwestern periphery of the CWA as steadier precip tapers off. Fcst highs should range from 55F in the Endless mtns and southern Poconos to ~70F in the far southwest corner of the CWA (near Confluence in Somerset County). Even with the advancing warm sector, scattered diurnal convection appears likely to the west of the Alleghenies Sunday afternoon which could spill into central PA late in the day as CAPE values increase. The SPC MRGL risk SWO clips a portion of Warren County. Everywhere else remains under general thunder. The CAD pattern loses its grip Sunday night into Monday as a weak cold front presses southeast from Lake Erie. This will allow for the possibility of night time convection along the cold front. Guidance has been bullish on fog development and the mention of it has increased in coverage in the wx grids. Fcst lows Sunday night are +10-20F above climo for early May in the low 50s to near 60F. Temperatures are forecast to bounce on Monday with fcst maxes getting back into the 70-80F range. High pressure and low pwat air should dry out the northern tier, but nearly stationary frontal zone will maintain a chance of showers/t-storms over south central PA through Monday night. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Unsettled weather is expected for the long term period with multiple chances for showers and thunderstorms. The first chance will come on Tuesday as a warm front lifts north of the area and moisture advection increases. The best chance for any showers or storms on Tuesday will be across the southwestern counties. Wednesday will be the warmest day of the period with highs in the upper 70s and 80s as the region will be in the warm sector of an approaching low pressure system. Most model guidance shows a weak wave of low pressure tracking to our north during the day on Wednesday along the warm front ahead of the primary low. This will bring more showers and storms to the area. The best chance for widespread showers and thunderstorms appears to be on Thursday as a cold front moves through. Locally heavy rainfall will be possible with ensembles showing PWATs approaching 1.3 inches across the southern tier along with surface CAPE of 500-1000 J/kg. A few stronger thunderstorms appear possible as well, as deep layer shear begins to increase as the upper level trough moves in. Temperatures will be on a downward trend behind the cold front and into the weekend. Highs on Saturday will range from the upper 50s across the northern and western mountains to the mid to upper 60s for the southeast. There is some disagreement in the models with respect to rain chances through the end of the period, but scattered showers appear likely as a couple of shortwaves ride through the southern edge of an upper low positioned to our north. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... A moist southeast flow preceding a slow-moving warm front in the Ohio Valley will produce low cigs and rain across the forecast area through at least Sunday morning. At 22Z, some MVFR cigs are noted across the eastern half of the state. However, all guidance points to deteriorating conditions overnight with widespread IFR/LIFR cigs by early Sunday morning. LIFR cigs are most likely where the southeast flow is forced to ascend the higher terrain of Central PA. Strengthening south-southwest winds aloft will result in marginal LLWS later tonight into Sunday morning. Bufkit soundings indicate the best chance of LLWS criteria being met will across the northern tier of the state. Little improvement in flying conditions are expected over most of Central PA Sunday, as a moist southeast flow off of the Atlantic persists. However, model soundings indicate some modest improvement is possible late in the day along and west of the spine of the Alleghenies. Outlook... Mon...AM low cigs/fog likely. Tue...Patchy AM valley fog possible, mainly Southern PA. Isold PM tsra impacts possible Western PA. Wed...AM low cigs possible NW Mtns. Thu...Rain/low cigs possible. PM tsra impacts possible southwest PA. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...DeVoir/Bowen NEAR TERM...DeVoir/Steinbugl/Bowen SHORT TERM...DeVoir/Steinbugl/Bowen LONG TERM...Bauco AVIATION...Fitzgerald