Area Forecast Discussion
Issued by NWS Albany, NY

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000 FXUS61 KALY 211732 AFDALY Area Forecast Discussion National Weather Service Albany NY 1232 PM EST Sun Jan 21 2018 .SYNOPSIS... Above normal temperatures will continue this weekend into early next week. A low pressure system will impact the region late tonight into Tuesday night bringing some mixed precipitation to the area and a moderate to locally heavy rainfall. Some freezing drizzle is possible for portions of the late tonight into Monday morning. A colder, seasonable airmass will be ushered back into the region behind the storm. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... As of 1230 PM EST...A cold front has stalled to our north across northern New York and northern New England and is expected to remain nearly stationary through the day today. Stratus clouds will continue to impact the area especially north and west of the Capital District. Warm air advection clouds will be on the approach from the southwest during the day but are not expected to reach the local area until after dark. Winds will be light. High temperatures will vary from the mid 30s to mid 40s in most areas. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY NIGHT/... An expansive southern stream low pressure system over the Plains will begin to impact the local area tonight as it moves towards the Great Lakes region. The system becomes vertically stacked and tracks across the Great Lakes Monday night into Tuesday with its cold front sweeping across the local area Tuesday. The system will deepen over New England Tuesday night as northern stream energy interacts with it. Isentropic lift will begin tonight with clouds overspreading the area and some spotty light precipitation is possible especially overnight into Monday. The challenge will be the temperature profile as surface readings fall some this evening and warmer air moves in aloft setting the stage for freezing precipitation. Freezing drizzle is the p-type expected, however confidence for it occurrence is not high enough or widespread enough to issue a winter weather advisory at this time. As boundary layer temperatures warms during the day Monday a changeover to drizzle and eventually rain is expected. However temperatures will struggle across portions of the southern Adirondacks, upper Hudson Valley and southern Vermont and portions of the Berkshires and should drop a couple/few degrees Monday evening so freezing rain is real threat. Precipitation is expected to remain light during the day Monday with steady precipitation developing Monday night especially late at night as the strengthening low level jet ahead of the low pressure system moves into the region. Guidance indicates the 850 mb jet should increase to 50 to 70 knots (2-3 standard deviations above normal) as it moves across the area mainly to south and east of the Capital District Tuesday morning. This will push precipitable water values up to around an inch (2-3 standard deviations above normal) and result in a period of moderate to heavy rainfall Tuesday morning with the bulk of the QPF falling at this time. This is expected to cause rises on rivers and streams, which may move and dislodge ice and may cause flooding near ice jams. With the passage of the cold front the moderate to heavy rainfall will come to an end. Rain will continue as the upper trough swings through. As the low moves off to our east Tuesday night a colder, seasonable airmass will be ushered in with linger rain changing to snow with some light accumulations possible. Temperature forecast is very tough tonight into Tuesday. How much do readings drop off tonight and how much they rise Monday? They should remain fairly steady Monday night with temperatures rising Tuesday ahead of the cold front. Tonight expecting upper 20s to lower 30s with temperatures in the 30s Monday and Monday night rising into mainly the 40s Tuesday. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... Medium-range deterministic models and ensemble guidance are in solid agreement that the long term period will be characterized by a return to wintry temperatures a bit below normal. It appears another warm-up will begin by Saturday. On Wednesday, persisting cyclonic flow and low-level cold air advection with H850 temps around -12C should support lake effect snow in favored locations of the Mohawk Valley and western Adirondacks. Low inversion heights expected to keep accumulations fairly light. Blustery as well Wednesday into Thursday with the cold advection. Subsident mid-level northwesterly flow builds in Wednesday night into Friday with accompanying high pressure at the surface, spelling an end to lake effect activity. Rather chilly during this timeframe with forecast lows in the single digits and teens, and highs in the teens and 20s, with winds making it feel colder through Thursday before the high sets up shop. Return flow looks to kick in by Saturday providing a boost to temperatures back above normal values. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Areas of low VFR stratus have expanded into KALB/KGFL with MVFR at KPSF with modest moisture advection beneath an inversion. Expect varying coverage of these stratus throughout the daylight hours today, with some high clouds as well. Tonight, low-level moisture advection will increase ahead of a low pressure system moving across the Great Plains. This should allow cloud bases to lower to MVFR and perhaps IFR levels late in the TAF period. The moisture advection may be accompanied by patchy drizzle or freezing drizzle as a warm front focuses the moisture, especially after 06Z. FZDZ appears relatively more likely at KGFL and KPSF where temps are expected to be lower, but cannot be ruled out at KALB/KPOU where temps may be around the freezing mark. Vsby restriction may exist in a combination of DZ and BR. Winds will be light and variable throughout the TAF period. Outlook... Monday: Moderate Operational Impact. Chance of RA...DZ. Monday Night: High Operational Impact. Definite RA. Tuesday: High Operational Impact. Definite RA. Tuesday Night: Moderate Operational Impact. Chance of SHRA...SHSN. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX. && .HYDROLOGY... Ongoing flooding due to ice jams will continue to be addressed with areal flood warnings, as some lingering issues continue due to existing ice jams which froze in place. Temperatures will continue to run above normal into early next week. Tuesday will be the mildest with highs mainly in the 40s a colder seasonable airmass returns Tuesday night. A storm will bring a moderate to locally heavy rainfall to the area. The rain is expected to be light during the day and in the evening Monday with the bulk of the rain occurring Tuesday morning. QPF amounts are forecast at this time to range from about an inch up to possibly 1 1/2 inches. The higher amounts across expected east of the Hudson River Valley and across portions of the central/southeastern Catskills. The rain is expected to cause rises on rivers and streams, which may move and dislodge ice and may cause flooding near ice jams. Our latest Winter/Spring Flood Potential Outlook (ESFALY) was issued Friday evening. 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...IAA NEAR TERM...IAA/11 SHORT TERM...IAA LONG TERM...Thompson AVIATION...11/Thompson HYDROLOGY...IAA is the U.S. government's official web portal to all federal, state and local government web resources and services.