Area Forecast Discussion
Issued by NWS Burlington, VT

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744 FXUS61 KBTV 300624 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 224 AM EDT Sat Jul 30 2016 .SYNOPSIS...
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Low humidity levels, mostly clear 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.
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&& .NEAR TERM /THROUGH TONIGHT/...
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As of 152 AM EDT Saturday...Tranquil and pleasant weather conditions through the 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 2-m dewpoints in the 50s today. Early AM valley fog will dissipate by 13Z, and then skies will be mostly sunny thru the day. 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 14-22Z generally N 5-9 mph, except locally NE across far nrn NY. PoPs NIL. Continued quiet tonight, though will see some mid-upper level clouds 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.
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&& .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... As of 415 PM EDT Friday...12z guidance not all that consistent, but consistent enough to indicate that there will be period of showers (perhaps a steady moderate rain) sometime between late Sunday into Monday, all in association with a trough swinging through. That trough and associated energy is currently back across Nebraska. Timing differences between the models, with ECMWF being the fastest (showers by Sunday morning), the GFS with it`s showers coming in during the afternoon, and NAM the slowest with nothing really until early evening. Stuck a little closer to the GFS as it seemed like a good compromise. Thus painting in increasing chances of showers from southwest to northeast during the day. Some interesting signals in the models for late Sunday/Sunday night. All models show some precipitation "bullseyes" where they indicate a small area of locally heavy rain. Doesn`t appear to be convective feedback, as models keep instability very minimal during the period. However over the course of 18 hours or so, QPF adds up in the models. GFS has a swath of 2-3" from south-central VT back across central NY. ECMWF has 2-3" almost everywhere across VT, with lesser totals west. NAM has 1-2" from central VT extending southwestward. Great variability in the model depiction. Think this is due to how each model handles the shortwave energy, which appears to come through in pieces, combined with convergence aloft around the 700mb level. Soundings do indicate a fairly juiced atmosphere, with Precipitable Water values around 1.5", fairly deep warm cloud depth (11-12k ft) along with rather weak winds, with 850mb trending southeasterly (hint of atlantic moisture tap). Bottom line, could see some downpours, perhaps Sunday night. For precip totals in the forecast, I went with an overall model blend including output from 00z model suite. End up with rainfall totals of 1-1.25" across South-Central VT. Lower amounts the further north you go -- just 0.25-0.33" or so up along the Canadian border. At this point don`t expect any flood issues. Ground in that part of the state is very dry (borderline moderate drought), and as long as the rain falls over several hours, the ground will absorb it. However, something that will need to be watched in later forecasts. As mentioned above, instability is very minimal, so primarily rain showers with only isolated rumble of thunder expected. Precipitation will be slow to end on Monday, with lots of clouds around. Temperatures Sunday 70s to perhaps lower 80s (depends on how quick the showers get in). Will be on the cool side Monday with all the clouds, just 70s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 415 PM EDT Friday...okay agreement between 12z suite of GFS and ECMWF. Both show a weak shortwave moving across early on Tuesday that should result in a few showers first thing in the day. Ridging aloft develops mid/late week, though ECMWF is much more pronounced with it. GFS is, like the 00z run, showing a flatter ridge. Even so, it should be dry Wednesday and Thursday. Perhaps an isolated shower in some of the higher terrain, but have PoPs less than 20% both days. A front will be approaching on Friday, though at this point the 12z runs keep us dry. With 00z runs having a slightly faster timing, have kept some 20-30 PoPs in for Friday, in the event later models speed up again. Probably the most noticeable aspect of the weather next week will be the increasing heat. GFS has 925mb temperatures of 20-22C on Wednesday and increases it to 24-26C by Friday. ECMWF is a little cooler. Thus looking at highs well into the 80s to even lower 90s by Thursday and Friday. 25C at 925mb typically translates to 35C (95F) at lower elevations. Not ready to go that warm yet, but followed the previous forecasters idea of upping high temperatures a few degrees from the base model blend. && .AVIATION /06Z Saturday THROUGH Wednesday/...
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Through 12Z Sunday...Localized LIFR fog SLK/MPV thru 12Z Sat, then SKC-FEW250 with light N-NE winds daylight hrs areawide. Continued VFR tonight with increasing mid-upr level clouds mainly after 06Z Sunday. Some chance of localized early AM fog SLK/MPV once again 06-12Z Sunday. Outlook 12z Sunday through Wednesday... 12z Sunday-00z Tuesday: Mainly VFR early Sunday, but then 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.
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&& .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Banacos NEAR TERM...Banacos SHORT TERM...Nash LONG TERM...Nash AVIATION...Banacos

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