textproduct: Binghamton

SYNOPSIS

High pressure will dominate our weather today through Friday with seasonable temperatures and no precipitation. A storm system approaching the area may bring a brief period of light freezing rain to parts of the area early Saturday, before changing to light rain. A steadier rainfall is expected Sunday into Monday, which may result in river rises and localized flooding.

NEAR TERM /THROUGH FRIDAY/

550 AM Update:

Made some minor adjustments to sky cover to reflect latest satellite trends. The eastern edge of the stratus deck is now almost perfectly aligned with the I-81 corridor in NY, extending southward into western Susquehanna County-central Wyoming County-western Luzerne County in Northeast PA. Otherwise, also made some minor tweaks to hourly temperatures for the next few hours. The rest of the forecast remains on track and the previous discussion remains valid.

300 AM Update:

The main forecast challenge in the immediate near term is the significantly varying temperatures early this morning. Where skies are clear (mainly east of I-81), radiational cooling has allowed temperatures to plummet into the single digits and lower teens. Meanwhile, a deck of low stratus is situated across most areas west of I-81, which has allowed temperatures to remain nearly steady in the mid to upper 20s. As there really isn't any model guidance that represents this sharp gradient in temperatures well, several hand-edits were made to the hourly temperature grids for the pre-sunrise hours.

High pressure will be in control of our weather for today, which will bring precipitation-free weather. The aforementioned cloud cover west of I-81 will be a bit slow to dissipate, but the expectation is that this will happen by this afternoon as the upper level ridge begins to move overhead. Aside from those clouds, skies will be mostly sunny today. Highs are expected to be in the upper 20s to mid 30s, which is a few degrees below normal for this time of the year.

Partly cloudy to mostly clear skies are expected tonight as high pressure remains in control. Some higher clouds may move in from the west, which may limit radiational cooling somewhat, but still went a few degrees below guidance with otherwise decent radiational cooling conditions expected. Lows are expected to be in the teens to lower 20s for most of the area, with perhaps some single digit readings across the usual colder spots of Oneida County.

High pressure will drift to the east on Friday, which will result in a southerly return flow. This will allow temperatures to be a few degrees warmer Friday with highs expected to be in the mid 30s to near 40. Most of the day will be partly sunny, but clouds will begin to increase from the west late in the day ahead of the next system. Any precipitation is expected to hold off until Friday night/early Saturday.

SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/

310 AM Update:

The peak of the upper-level ridge will move off to the east Friday night while a trough will swing northward into the Great Lakes region. Southwesterly flow will advect moisture into the region and there will be enough lift to kick off some rain showers late Friday night and early Saturday morning. There is a warm nose present from around 950mb to 700mb but at the surface temperatures are right at or below freezing. This will lead to patchy freezing rain/drizzle for most areas other than the Finger Lakes region. Models do not have much for ice accumulation but a light glaze of ice cannot be ruled out. Lows Friday night will range from low 20s to low 30s with valleys having the best chance of hanging onto the 30s.

Temperatures should be fairly quick to warm up during the day, so any remaining freezing rain after sunrise should transition to just rain by the mid to late morning hours. As the trough lifts north, the best chance for rain showers will be across the Wyoming Valley, Poconos, and even the Catskills as the band of rain hugs the coast. Some spotty showers cannot be ruled out elsewhere, but many models keep conditions drier through late Saturday evening. Seeing this, PoPs were lowered below NBM guidance for Saturday. Temperatures will max out in the 40s before dropping into the 30s and low 40s Saturday night. A more broad upper-level trough will sweep through the Midwest Saturday night. This will drive a surface low up the backside of the departing ridge, bringing widespread rain with it beginning late Saturday night.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

310 AM Update:

Widespread showers will continue through at least Sunday night as strong southerly flow will advect warm, moist air into this system. There is uncertainty where this system will track and if a dry slot will form somewhere over the region. Despite this uncertainty, there remains concerns for hydro issues. The PWATs are 2 to 3 standard deviations above normal for this time of year. Models show anywhere from 1 to 2 inches with locally higher amounts closer to 3 inches for total precipitation through the weekend time period. This will fall on top of the current snow cover and frozen ground. NOHRSC analysis and core measurements at the office have snow water equivalents (SWE) at an inch or less. Ensemble guidance have low probabilities of the typical trouble points reaching minor flood stage. WPC continues to have a marginal risk for excessive rainfall over the region for Sunday. Any potential flooding will be our main concern but there may also be non-severe thunderstorms late Sunday. Models are showing limited instability across PA, though this instability is elevated. Given the strong low-level flow, shear will be high. Confidence was too low to include thunder in the grids given the late timing of instability in the area, but it will be worth monitoring for a low CAPE/high shear thunderstorm potential.

Rain will likely continue into Monday as this system moves out of the region. As the upper-level ridge sweeps through, some wraparound moisture will also be present, so some showers may linger over north- central NY later while most others dry out. Surface high pressure will build into the region Monday night and keep conditions dry through Tuesday. Another low pressure system will bring the next round of precipitation to the region Tuesday night into Wednesday. Conditions initially will be warm enough for rain but cooler air will begin to filter in from the northwest and could lead to a rain/snow mix or even just snow by late Wednesday.

Over the next seven days, temperatures will be warmest Sunday as 50s return for highs and low will only be in the upper 30s to mid 40s Sunday night. Temperatures will then trend cooler through midweek but will remain above average for late December/early January.

AVIATION /12Z THURSDAY THROUGH MONDAY/

The eastern edge of a MVFR to Fuel Alternate stratus deck will continue to impact the majority of terminals this morning, although a bit of uncertainty is present for KRME and KAVP. KRME may remain mainly VFR this morning with the stratus deck located just to the south and west. For KAVP, while the majority of the guidance keeps VFR conditions there this morning, the eastern edge of the stratus deck continues to advance closer and is on track to arrive there by around 13Z or so, assuming it doesn't retreat back to the west before then. Added in a TEMPO for MVFR ceilings there for 13-16Z.

The other tricky part of the forecast is how long it takes this deck of clouds to dissipate during the day today. Current expectations are that the clouds will scatter out by this afternoon, resulting in a return to VFR conditions, although KELM may have clouds linger a bit longer. Then late tonight/early Friday morning, MVFR ceiling restrictions are expected to return to most terminals.

Outlook...

Friday through Friday evening...Mainly VFR.

Late Friday night through Saturday...Occasional restrictions possible in scattered rain showers. Some freezing rain possible late Friday night/early Saturday morning.

Sunday through Monday...Rain and associated restrictions likely.

BGM WATCHES/WARNINGS/ADVISORIES

PA...None. NY...None.