Area Forecast Discussion
Issued by NWS Burlington, VT

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000 FXUS61 KBTV 301929 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 329 PM EDT Sat Jul 30 2016 .SYNOPSIS... Low humidity levels, partly to mostly sunny skies, and pleasantly warm temperatures will characterize Saturday, as Canadian high pressure controls our weather through tonight. Thereafter, a slow moving upper level disturbance and associated rich moisture moving out of the Ohio Valley will bring periods of rain showers Sunday into Monday, possible lingering into early Tuesday. High temperatures will reach the low 80s today, but then generally in the low to mid 70s for the Sunday through Tuesday time frame with abundant cloudiness. High pressure returns Wednesday through Friday with warmer and more humid conditions. && .NEAR TERM /THROUGH SUNDAY/... As of 140 PM EDT Saturday...Tranquil and pleasant weather conditions through the rest near-term period. Dry northerly low- level airstream continues east of 925mb anticyclone centered across swrn Quebec. This will continue to provide the North Country with relatively low humidity (2-m dewpoints in the 50s) today. Mid-upper level clouds streaming enewd ahead of Ohio Valley trough are staring to dissipate in the nid afternoon hours but will still provide filtered sun especially over the srn half of the forecast area. With 850mb temps of +11C to +13C at 21Z per 00Z GFS, looking for highs generally in the upr 70s to lower 80s. 10-meter winds generally N 5-9 mph, except locally NE across far nrn NY. PoPs NIL. Continued quiet tonight, though will see some mid level clouds (8-10 KFT) increasing from SW-NE after midnight as slow-moving 500mb trough shifts newd from OH into PA/wrn NY. Included slight chance of showers s-central VT toward 12Z Sunday, but most likely scenario is that associated shower activity remains south of the entire forecast area until during the day Sunday. Overnight lows mid-upr 50s, except locally around 60F s-central VT valleys where clouds inhibit radiative cooling. Some patchy valley fog is possible nrn valleys after 06Z Sunday. && .SHORT TERM /SUNDAY NIGHT THROUGH MONDAY NIGHT/... As of 325 PM EDT Saturday...Rain shield will continue to slowly advance northward Sunday night and into Monday, offering a wet close to the weekend. Both global and mesoscale model QPF output continues to suffer from model- generated convective bullseyes in their respective QPF fields in various different locations. While PWAT values are seasonably high around 1.5 to 1.7", there really isn`t much in the way of instability to speak of given the time of day, overcast skies and poor low and mid-level lapse rates. Because we aren`t likely to see much in the way of thunder to enhance rainfall rates, think higher QPF as seen in some guidance and WPC seems a bit overdone. Generally stuck close to 15z SREF/12z GFS/12z NAM blend for PoPs/QPF/Wx. A steady light to moderate rainfall seems the more likely outcome with the heaviest precip falling Sunday night into early Monday. It appears the steadiest precip generally comes in two waves - one is the south- to-north moving axis associated with the warm front, and another later in the day Monday from the upper trough axis. While rainfall should provide beneficial given the dryness, there may be areas of localized ponding in poor drainage areas. Factoring in rainfall for Sunday, forecast amounts are between 0.75" to 1.25". Should greater instability be realized that currently indicated, these values may be locally higher. Temperatures Sunday night stand to be pretty mild and more humid. With anticipated cloud cover and at least a light south wind, expect temperatures to fall very slowly to lows in low to mid 60s, a few degrees warmer than recent MAV/MET MOS output. On the flip side, high temperatures Monday were undercut a couple degrees compared to MOS given the extensive cloud cover. Values are in the low 70s, only a few degrees higher than lows the evening before. Lows Monday night in the upper 50s to lower 60s. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 325 PM EDT Saturday...After a wet Monday, global models then point to mid-level height rises associated with ridging aloft Tuesday through Thursday. GFS and ECMWF want to show isolated showers or thunderstorms but this seems overdone and have kept the forecast dry. 850 mb temperatures warm each day and are up in the +13 to +15C range supporting another period of above-normal temperatures in the low to mid 80s. Thursday will continue the trend of above-normal temperatures, but we will start to see more of a southwesterly breeze and also an increase in humidity levels. Still dry but warm and humid with highs into the upper 80s (maybe spot 90) with lows Thursday night in the upper 60s. It appears Friday potentially may have a window for active weather as mid-level flow tightens across the Great Lakes and wind fields strengthen, as a cold front moves into a warm and humid antecedent air mass. There`s some difference between the GFS and ECMWF when the front crosses through our area Friday, which has implications on available instability, with the GFS suggesting an afternoon frontal passage. It`s very early but on the synoptic scale, there appears to be potential for stronger thunderstorms Friday. Definitely is something that should be monitored in subsequent model runs. && .AVIATION /20Z Saturday THROUGH Thursday/... Through 18Z Sunday...VFR conditions will persist through most of the period. High and mid-level clouds are filtering from the south but most are dissipating as they move into the region. Overnight increased moisture will bring lower VFR ceilings. If ceilings don`t not move in fast enough, there is potential for overnight IFR fog at MPV. Have decided to leave out the mention in the TAFs for now. Showers will move slowly in late into the period into the southern stations after 15Z. Winds will be light and variable for the period. Outlook 18z Sunday through Wednesday... 18z Sunday-00z Tuesday: Intervals of MVFR in shower activity Sunday afternoon through Monday with slow moving upper trough. 00Z Tuesday through Wednesday: Upper trough brings lingering showers Monday night into early Tuesday with periods of MVFR and brief IFR possible. Then clearing with VFR conditions as high pressure returns Tuesday afternoon through Wednesday. May see areas of nocturnal fog 06-12Z Wednesday SLK/MPV with localized LIFR conditions. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...Banacos/MV SHORT TERM...Loconto LONG TERM...Loconto AVIATION...Banacos/MV is the U.S. government's official web portal to all federal, state and local government web resources and services.