Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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847 FXUS61 KCTP 291731 AFDCTP Area Forecast Discussion National Weather Service State College PA 131 PM EDT Wed May 29 2024 .SYNOPSIS... *Numerous showers/t-storms expected this afternoon and evening *Drying trend to end May with below normal temperatures *Temperatures warm to near normal to start June with rain chances increasing into early next week && .NEAR TERM /THROUGH TONIGHT/... The main band of thunderstorms associated with an approaching surface low is continuing to work its way northward and is just through State College as of 17Z. Most guidance suggests that the northward progression of this band will slow over the next few hours and may sit over the area north of I-80 for a while. Repeating heavy downpours in this area could produce local QPF maxes around 1.5-2" as they maneuver over the region into the evening, and even though PWATs are fairly low (only around 1"), there could be some localized flooding concerns. WPC has added a sight risk of excessive rainfall for the northern portion of the CWA as a result. Showers and thunderstorms will be possible elsewhere across Central PA as well into the evening, but they will not pose as much of a heavy rainfall threat. Max temps will be 5 to 10 degrees below late May climo across most of CPA this afternoon with highs in the 60-75F range. Shower activity shifts to the east tonight with patchy fog possible over the western Alleghenies where skies should clear out. Seasonably cool night ahead with lows in the 40-55F range. && .SHORT TERM /THURSDAY THROUGH SATURDAY/... Final shortwave trough rotates through CPA on Thursday. A couple of showers or an isolated PM t-storm are possible Thursday afternoon beneath the upper trough axis mainly over southeast PA, but lower pwat air pouring into the region via NNW low level flow should keep most places dry. Highs will again be cooler-than-average with fcst max temps in the low 60s/70s. Seasonably strong high pressure dome migrates eastward from the OH Valley Thursday night into western PA early Friday morning. This setup should support one of the coolest nights in a while with low temps in the mid 30s to upper 40s. With light winds and mainly clear skies across the northern tier, some patchy frost cannot be completely ruled out. Center of 1025mb sfc high is parked right overhead by 12Z Saturday, ensuring the break in the rain continues into the first weekend of June. Look for max temps to rebound a bit on the last day of May with highs staying near/below climo. Another relatively cool night with lows in the 40-50F range. && .LONG TERM /SATURDAY NIGHT THROUGH TUESDAY/... Models diverge with the amplitude of a shortwave trough moving through the region late Saturday night into Sunday. This feature will bring the next chance of showers and thunderstorms to central PA. Longer range guidance shows multiple shortwaves moving through the region into the middle of next week bringing renewed chances for showers and storms, but confidence in the timing of these features is low. && .AVIATION /18Z WEDNESDAY THROUGH MONDAY/... (V)LIFR conds across the western highlands (BFD/JST) will continue for the next hour-two before giving ways to a brief period of VFR conditions. A period of showers this morning is likely to get to JST/BFD by 14Z Wednesday with less confidence further east so have left mentions out at this time. Within these showers, low-end VFR seems like the most likely options although cannot rule out a brief drop towards MVFR vsbys/cigs. Later this afternoon, higher coverage of SHRA is expected to develop with showers and thunderstorms expected. Brief visibility restrictions are possible in any heavier showers and storms (see below) with cigs borderline MVFR/VFR based on recent model guidance. Elevated CAPE does indicate higher chances of TSRA as these showers progress across the area today. This TAF package has tightened up some of the TSRA mention timing although some uncertainty still exists on exact coverage. Guidance indicated towards lowered vsbys/cigs at BFD/JST overnight into Thursday, which seems plausible given increased low-level moisture, light winds, and potential for some clearing skies. The main uncertainty at this time remains how quickly clouds clear out, which could limit fog potential across the western highlands. Recent guidance does suggest an earlier clearing time, so have outlined IFR/LIFR restrictions with some added uncertainty with regards to timing. Outlook... Wed Night-Sat...Predominantly VFR. Sun...Showers and thunderstorms possible. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl NEAR TERM...Steinbugl/Bauco SHORT TERM...Steinbugl/Bauco LONG TERM...Colbert/Bauco AVIATION...NPB