Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 120910 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 410 AM EST Wed Dec 12 2018 .SYNOPSIS... Chilly and mainly dry weather is expected through Thursday, with some light snow showers possible Thursday. Milder temperatures arrive Friday into the weekend, along with periods of rain. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 410 AM EST, still quite a bit of clouds across the region, although some breaks were developing across portions of the upper Hudson Valley. Some lingering snow showers/flurries continue across portions of the Taconics/southern Greens and Berkshires. With widespread clouds and some wind, temps remain in the lower/mid 20s in many areas, with even some temps near 30 close to the Capital Region. Tough call once again for today regarding cloud cover. While abundant at this time, we expect breaks to develop within the Hudson Valley region through the morning, as a combination of increased subsidence in the wake of the passing shortwave, and some downsloping occur. Across higher terrain areas, clearing may be more gradual, occurring later this morning across the Taconics/southern Greens/Berkshires, and last across western areas such as the Mohawk Valley, eastern Catskills and SW Adirondacks. Some flurries/snow showers may also linger a bit past daybreak across portions of the Taconics/southern Greens and Berkshires, where scattered additional coatings are possible. Temps should reach the lower/mid 30s in most valley areas, with mainly mid/upper 20s across higher terrain areas. Some portions of the mid Hudson Valley and lower elevations in Litchfield County could approach 40. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY NIGHT/... Tonight, clear skies early, before high/mid level clouds increase from SW to NE later this evening and overnight ahead of a compact shortwave approaching from the southern Great Lakes region. There is a slight chance that some light snow/snow showers develop between 3 and 6 AM for areas mainly south of I-90/I-88, per some hi-res models suggest, although with low levels remaining very dry, some of this may be tough to reach the ground. Low temperatures should reach the single digits above to slightly below zero across the southern Adirondacks and southern VT, where skies remain clear longer, with mainly teens farther south and west as clouds increase and limit radiational cooling potential. Thursday, aforementioned compact shortwave looks to track east across northern PA or southern NYS, while weakening within overall confluent flow aloft. Deformation along the northern periphery of this feature should allow for at least some forcing to produce light snow or snow showers, which will be mainly from the I-90/I-88 corridor south and west. Dry low levels could limit how much reaches the ground, however enough forcing could allow for some spotty light accumulations of a coating to less than an inch in some of these areas, with best chances across higher terrain areas of the SE Catskills. Otherwise, mostly cloudy with high temps mainly in the mid 20s to lower/mid 30s. Thursday night-Friday night, initial weakening shortwave departs off the New England coast, before increasing isentropic lift ahead of next system overspreads region from southwest to northeast Friday afternoon and night. Expect a general lull in precipitation Thursday night, however with developing low level warm advection and increasing Atlantic moisture, some patchy freezing drizzle or snow grains could occur across portions of the SE Catskills and perhaps mid Hudson Valley, especially late Thursday night into Friday morning. Will include some mention of patchy freezing drizzle/drizzle in these areas, but overall low confidence remains at this time for this to occur, especially for lower elevations in the mid Hudson Valley. Better chances for precipitation arrive Friday afternoon and Friday night. Wet bulb cooling processes could lead to areas of snow or a rain/snow mix across higher terrain areas of the SW Adirondacks, southern VT, and the Berkshires, especially at precipitation onset. Also, if low level cold air remains anchored, some freezing rain can not be ruled out as well in some northern areas, and trends will need to be watched as we get closer in time. Lows Thursday night mainly in the 20s, highs Friday warming into the mid 30s to lower 40s, and lows Friday night mainly in the mid/upper 30s except for lower 30s across portions of the SW Adirondacks, southern VT and Berkshires, and possibly portions of the Mohawk and upper Hudson Valley. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Upper level split flow still affecting the consistency of long range guidance/ensembles. There is still considerable spread in the track and timing of northern stream dominated upper energy and moisture. Northern stream upper energy looks strong and low level forcing along the leading edge of cold advection looks strong but moisture lacking. Also, boundary layer temperatures are predicted to be warmer than temperatures below the boundary layer, implying that the scattered coverage of precipitation could involve patchy light sleet or freezing rain when we do have chances for precipitation. However, this is really the first indication in long range guidance for chances for mixed precipitation. Also, there are considerable differences in the predicted amounts of moisture during the time window of the potentially best upper dynamics and low level forcing ahead of 2 cold fronts, one in the Saturday and Saturday night time frame and the other in the Monday time frame. Regardless of how the track, timing and moisture get sorted out, quite a bit of cloudiness and at least chances for rain and snow showers through Monday. More details will be known as we get closer and changes to the forecast can be expected between now and next weekend as details get clearer. Highs Saturday in the 40s with some upper 30s northern areas. Highs Sunday and Monday in the 30s to near 40 with a few lower 40s southern areas. Highs Tuesday in the 30s but mid to upper 20s higher terrain. && .AVIATION /09Z WEDNESDAY THROUGH SUNDAY/... Upper system exiting and low level flow across Great lakes has supported extensive cloud cover over our region with some snow flurries at times. Clouds and flurries will continue through about 09Z-11Z at KGFL, KALB and KPSF. The flurries are expected to stay north of KPOU but the cloud cover will persist there. Some flurries around KPSF could bring the ceiling down to around 1500 feet at times through about 10Z. Clouds will break up through the morning as the upper energy exits and low level flow turns more north. Ceilings above 3000 feet should break up at KPOU by mid morning and the rest of the TAF sites around midday or early afternoon. The sky will become clear and remain clear through this evening. Light and variable winds through mid morning will become northwest to north at less than 10 Kt, continue through the afternoon and then diminish to light this evening. Outlook... Thursday Night: No Operational Impact. NO SIG WX. Friday: Low Operational Impact. Slight Chance of RA. Friday Night: High Operational Impact. Likely RA. Saturday: Moderate Operational Impact. Likely SHRA...RA. Saturday Night: Moderate Operational Impact. Scattered SHRA...SHSN. Sunday: Low Operational Impact. Isolated SHRA...SHSN. && .HYDROLOGY... No hydrologically significant precipitation is expected through at least Thursday. Temperatures averaging below normal, and mainly below freezing, will support expansion and thickening of ice on area waterways. A warm-up appears possible Friday into the weekend ahead of a strong low pressure system approaching from the southern US. There is still considerable uncertainty on the track of this system and resulting QPF. Current indications are for areas from the Albany-Saratoga region through southern VT and points south and east receiving 0.25-0.50 liquid equivalent, while areas to the north and west receive mainly under 0.25". However, should the low pressure system track slower and farther north, greater rainfall amounts would occur. For details on specific area rivers and lakes, including observed and forecast river stages and lake elevations, please visit the Advanced Hydrologic Prediction Service /AHPS/ graphs on our website. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...KL/Thompson NEAR TERM...KL SHORT TERM...KL LONG TERM...NAS AVIATION...NAS HYDROLOGY...KL/Thompson is the U.S. government's official web portal to all federal, state and local government web resources and services.