Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 271952 AFDALY AREA FORECAST DISCUSSION National Weather Service Albany NY 252 PM EST Sat Feb 27 2021 .SYNOPSIS... Dry weather will return to the area tonight as high pressure builds into the area. Another system will move across the region later Sunday with periods of rain and perhaps a wintry mix across the higher terrain. A strong cold front will cross the area later Monday, possibly accompanied by some snow squalls and followed by much colder temperatures. && .NEAR TERM /THROUGH TONIGHT/... A band of precipitation will track from the Champlain Valley east across Vermont late this afternoon. This precipitation will fall mostly as a little rain at lower elevations north of the Captial District, with a little rain and snow mixed at higher elevations into the Green Mountains. The precipitation will be east of our area by early evening, and some breaks in the cloud cover should develop overnight, especially over the Hudson Valley, as high pressure builds southeast toward the area. The airmass associated with this high pressure is not particularly cold, and no lake response over and east of Lake Ontario is expected, which should help with some clearing overnight. Low temperatures tonight will be mainly in the 20s to near 30. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The next wave of low pressure will approcah our area on Sunday. This next system looks to be a combination of two unphased waves; one approaching from the Great Laks and one from the Tennessee Valley. Model consensus is good that the heaviest precipitation associated with the Tennessee Valley wave will track just south of our area, while precipitation associated with the northern branch wave will be heaviest to our north and west. Despite this split in the pattern, it looks like at least some light precipitation will be overspreading the area Sunday afternoon and continuing Sunday night. With the timing of the precipitation not until later Sunday, all areas should be above freezing before the onset of the precipitation and the p-type with this next system should be mostly rain. A little wet snow could mix in over higher higher elevations north and west of the Capital District, but no accumulations are expected. Periods of light rain will be widespread across the area Sunday night as this unphased system crosses the area. After the passage of these waves, there should be some clearing early Monday as weak cold advection develops. Temperatures will likely recover into the upper 30s and 40s in this pattern by early Monday afternoon, then a strong cold front will approach from the northwest later Monday. West-southwest winds will increase ahead of this system, and will likely become quite gusty before shifting to the northwest Monday evening. In addition, some snow showers will likely develop west of the Hudson Valley Monday afternoon, and could intesify into heavier squalls late in the day or Monday evening. Models are indicating some instability ahead of this system and with surface temperatures likely to reach the 40s just ahead of the front some small amounts of CAPE appear to be possible. The best chance for up to 2 or 3 inches of snow with this system will likely be over the western Mohawk Valley and southwest Adirondacks, but one or two squalls could reach as far east as the Capital District Monday evening and this will have to be watched. The cold front will be followed by blustery and much colder weather later Monday night. The flow appears to have enough of a northerly component behind this front so that most of the lake effect will shift into central NY rather quickly overnight, so that no major accumulations are expected for our areas east of Lake Ontario. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A fairly benign weather pattern is upon us as we head into the long term period. We begin on Tuesday with an anomalously cold airmass in place. The latest GEFS 850mb temps of -20 to -25C are 2 to 3 standard deviations below normal. This should translate to high temps below freezing area-wide (teens in the southern Dacks). In addition to the chilly temps, winds will also be gusty out of the northwest. So despite plentiful sunshine, temps will feel quite chilly throughout the day. The upper trough responsible for the cold airmass departs by Tuesday night with a general zonal flow setting up across the northeast. A northern stream trough looks like it will stay set up across Quebec and at times dip down into New York and New England throughout the remainder of the long term period. This may lead to a period of light lake effect snow showers downwind of Lake Ontario on Thursday. But all of the southern stream energy is progged to stay south of our region and therefore, looks like a mostly dry forecast. Temperatures will be above normal Wed-Thur, with highs in the mid 30s to mid 40s. A brief return to seasonable temps is expected Fri- Sat as the upper trough dips south, but temps return to above normal by the end of the weekend. Overnight lows will be the coldest of the period Tuesday night with temps in the single digits to upper teens. Lows for the remainder of the long term period look fairly seasonable. && .AVIATION /20Z SATURDAY THROUGH THURSDAY/... Through 18z/Sunday.... The main aviation weather concerns for the ALY terminals during this TAF cycle includes: * Short-term IFR/LIFR cigs/vsbys * Short-term low-level wind shear (LLWS) concerns * Southerly winds this afternoon shifting out of the west-northwest this evening/tonight * Potential for some mist/fog development overnight tonight depending on how much of a factor winds will be and the amount of low level moisture in place As of 12:30pm EST, GOES-16 Visible satellite imagery depicted a low level IFR/LIFR cloud deck over the area. The WSR-88D Doppler Radar indicated a second batch of rain showers moving into our northern counties (set to impact KGFL in the 18z-20z time frame). Drizzle/mist has also been noted over the region ahead of an occluded frontal boundary. The lower levels of the atmosphere remains very saturated per forecast soundings from the BUFKIT. IFR/LIFR ceiling and visibilities conditions should improve to MVFR levels by 22-23z this evening. Once the aforementioned occluded front passes tonight between 00z-05z, winds are expected to shift out of the west-northwest allowing for colder, drier air to advect into the region. This could help scour out any low level clouds allowing for conditions to return back to VFR. KPSF is the one site that could still be dealing with MVFR conditions after 05z. However, by 10z, KPSF could improve to VFR levels. Mostly cloudy skies will look to stick around as another disturbance approaches the region from the south on Sunday. This next disturbance could bring the area the chance for some showers on Sunday. Southerly winds of 5-15 kts this afternoon will shift out of the west-northwest later tonight. There`s the potential for winds to gust 20-25 kts at KALB/KPSF. Winds are to decrease in speed becoming light and variable overnight into Sunday morning. Outlook... Sunday Night: High Operational Impact. Likely SHRA. Monday: Low Operational Impact. Breezy. NO SIG WX. Monday Night: Moderate Operational Impact. Windy With Gusts To 34 kts. Chance of SHSN. Tuesday: Low Operational Impact. Breezy. NO SIG WX. Tuesday Night: No Operational Impact. NO SIG WX. Wednesday: No Operational Impact. NO SIG WX. && .HYDROLOGY... No major hydrologic issues are foreseen through the middle of next week. Some melting and sublimation of the snowpack in the valleys is expected during the day time over the next several days. NERFC forecasts show minor up and down changes in river flows due to the diurnal freeze/thaw cycle. River ice is not expected to break up over the next several days. Low pressure tracking across the area later Sunday and Sunday night will bring mainly rain. Total QPF for this system will range from 0.10 to 0.30 of an inch. A strong cold front with snow showers is expected to move through later Monday through Monday night. Much colder air returns Monday night and Tuesday. 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...MSE NEAR TERM...MSE SHORT TERM...MSE LONG TERM...Wasula AVIATION...Evbuoma HYDROLOGY...NAS/Rathbun is the U.S. government's official web portal to all federal, state and local government web resources and services.