Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 272007 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 407 PM EDT Sat Aug 27 2016 .SYNOPSIS... A ridge of high pressure will move east of the region overnight. An upper disturbance over the Great Lakes will approach the region Sunday with a chance for showers and thunderstorms Sunday afternoon and Sunday night. a cold front will move south from Canada Sunday night and early Monday. A ridge of high pressure will then build into the north country Monday night and Tuesday. && .NEAR TERM /THROUGH SUNDAY/... As of 407 PM EDT Saturday...Expecting mainly clear skies through midnight, as a ridge of high pressure move east of the region overnight. Expecting mid and high clouds to be on the increase after midnight as clouds from an upper disturbance over the Great Lakes moves into the region. Have gone a bit above mos guidance for min temperatures overnight due to increasing cloud cover and surface winds shifting into the south overnight. A dry night is expected overnight. Have included a mention of some patchy dense valley fog over the Connecticut valley after midnight tonight, as this area had some fog this morning. On Sunday, expecting showers and thunderstorms to develop across the region by Sunday afternoon as an upper disturbance shifts east from the Great Lakes. Instability is marginal Sunday afternoon, so have stuck with mainly chance pops for now. SPC has area in a general thunderstorm outlook for Sunday. Precipitable water values per bufkit forecast soundings climb to over 1.5 to near 2 inches in some areas by Sunday afternoon. 0-6km bulk shear is around 30-40 knots Sunday afternoon, so any storms that do develop should move along and not stall over the region. Some brief locally heavy rainfall may be possible with any storms that do develop. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 330 PM EDT Saturday...Short term period picks up with the surface front on the St. Lawrence Valley doorstep and southerly flow ahead of it. Plenty of low level moisture streaming northward ahead of the front, with precipitable water over 1.5 inch until the front passes. Residual daytime heating, low level forcing along the front, and weak 500 mb dynamic support in the form of a sheared vort center. Kept chance to low likely pops going 00 to late evening, then tapers off. As the vort center passes the 500mb flow flattens, with a secondary and better defined shortwave trough moving across the area Monday in northwest flow. Despite the second trough on Monday precip chances decrease as northwest low level flow brings in much drier air. Slight chance to chance pops continue over higher terrain from 00-18z Monday, then dry thereafter. Clearing late Monday into Monday night with 1000-500 mb RH dropping below 30%. Fog formation possible Monday night under surface and upper ridging and clear skies for good radiational cooling, but didn`t include in forecast this far out. For temps, Sunday night still relatively warm with residual moisture limiting lows into the 60s. Highs Monday a little cooler under lower heights and 850 mb temps cooling to around 11C in support of max temps in the 70s. By Monday surface boundary is located just east of our cwa...with any lingering showers quickly ending as much drier air advects into the region. Progged pw values fall below 1.0 with moderate cold air advection on breezy northwest winds. 850mb temps cool 4 to 6 degrees by 12z monday with highs mainly in the 70s anticipated. will mention low chc pops in the morning for eastern areas. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 312 PM EDT Saturday...On Tuesday...surface high quickly shifts into the Gulf of Maine...as return flow develops ahead of approaching boundary. Northwest upper flow over the region, with 500mb shortwave trough moving through central Canada towards forecast area trough passes well north of region Tuesday night/Wednesday, dragging a surface front behind. Return of moisture, weak instability and frontal lift good for chc showers in the north Tuesday night and areawide Wednesday. Strong low level cold air advection follows boundary on Thursday into Friday with 850mb temps falling between 2 and 4c. This low level thermal profiles supports temps dropping back to below normal by Thursday with highs mainly in the 60s to lower 70s and lows in the 40s to mid 50s. Expect mainly terrain driven showers on Thursday into Friday associated with upslope flow and some mid level moisture. Will mention schc/low chc pops for the mountains of NY into northern VT...based on position of closed 5h trof and available moisture. && .AVIATION /20Z Saturday THROUGH Thursday/... Through 18Z Sunday...mainly VFR through the period. Expecting cumulus clouds over the Adirondacks and Green Mountains to dissipate by 00Z Sunday, due to the loss of daytime surface heating. Expecting a gradual increse in high and mid level clouds overnight as a weak disturbance approaches from the Great Lakes. There could be some light scattered rain showers over northern New york between 15Z-18Z Sunday. Surface winds expected to be mainly less than 10 knots through the period. Outlook 18Z Sunday through Thursday... 18Z Sunday through Thursday...mainly VFR through the period with high pressure. Two main threat periods for scattered showers and brief MVFR conditions - Sunday afternoon and Sunday evening, then again Tuesday afternoon/Wednesday with weak trough passages. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...WGH NEAR TERM...WGH SHORT TERM...Hanson LONG TERM...Hanson AVIATION...WGH

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