Area Forecast Discussion
Issued by NWS Burlington, VT
Issued by NWS Burlington, VT
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589 FXUS61 KBTV 210742 AFDBTV Area Forecast Discussion National Weather Service Burlington VT 342 AM EDT Sun Jul 21 2024 .SYNOPSIS... A cold front dropping south this morning will produce scattered showers through the morning hours. High pressure will build into the region this afternoon with dry weather expected through the daylight hours on Monday. Rain chances will begin to increase Monday night as a warm front lifts northwards with periods of rain expected through Thursday. Rain could be heavy at times, especially on Thursday, but no flooding is expected at this time. && .NEAR TERM /THROUGH MONDAY NIGHT/... As of 341 AM EDT Sunday...A cold front continues to make steady but slow progress this morning with 3 AM observations still showing the frontal boundary just north of the International Border. Scattered to numerous rain showers have developed ahead of the cold front near the International Border with rainfall amounts ranging from a few hundreths of an inch in northern Vermont up to a third of an inch across far northern New York. Models, surprisingly, are not handling this precipitation very well with the 00Z run failing to initialize the ongoing shower activity ahead of the cold front. Initially, it appeared that showers would be isolated to maybe scattered, However, current radar imagery shows a full line of showers extending from southern St. Lawrence County into the Northeast Kingdom. The use of forecast soundings was very beneficial to the forecast tonight because although models are struggling to depict ongoing rainfall, the soundings do show weak omega and very shallow instability ahead of the front. These two parameters are likely allowing the more widespread shower activity that should slowly dwindle with time as the convergence along the front weakens as we head into the late morning hours. A dry air mass is expected to quickly filter into the North Country in the wake of the cold front this afternoon with plenty of sunshine expected by early to mid-afternoon. Temperatures will be quite pleasant with highs in the 70s and decreasing humidity. Given the clearing skies, it`s a safe bet that we will be in store for patchy to possibly dense fog in the favored locations of northern New York and Vermont with high pressure building overhead as well. This fog will mix out after sunrise on Monday with another nice day, albeit noticeably warmer, on tap across the region. Cloud cover will increase later in the day on Monday as rain showers begin to lift north towards southern Vermont. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 341 AM EDT Sunday...A meandering frontal boundary and increasing moisture will bring chances for rainfall Monday night into Tuesday, marking the start of a fairly active period of weather. There is still some uncertainty with the actual location of where the frontal boundary will set up, but model guidance continues to show the axis of heaviest precipitation closer to southern New England. Despite this, precipitable water values will near 1.7 inches which will allow for some possible periods of moderate to heavy rainfall, although marginal instability across the region will help limit convection and the heavy rain threat. Temperatures during the day on Tuesday will be seasonable, with highs in the 70s to low 80s and lows generally in the 60s. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 341 AM EDT Sunday...The active period of weather continues through mid-week as the frontal boundary remains across the Northeast. Several impulses will traverse along the boundary Wednesday and Thursday, bringing additional chances for rainfall. While no day will be a complete washout, several rounds of showers and possible thunderstorms can be expected across the region. Looking at model soundings, Thursday currently looks more favorable for developing convection with the primary threat being heavy rainfall given the high PWAT values and decent and modest tall and skinny CAPE profiles. With continued chances for showers each day, WPC has the forecast area in a Marginal Excessive Rainfall Outlook (ERO) for Thursday, although the main threat will be in any locations that receive multiple rounds of showers and heavier rainfall. The potential for showers is still dependent on where the frontal boundary sets up, so any shifts will influence how much rainfall to expect and trends will continue to be monitored. Temperatures will generally remain seasonable, with high temperatures in the upper 70s to mid 80s although it will feel quite humid with dewpoints increasing into the 60s to lower 70s. Heading into the weekend, a period of drier and seasonable weather looks to return as a cold front ushers in a drier airmass and high pressure begins to build into the region. Temperatures will increase through the weekend under strong ridging, with some locations warming into the upper 80s. && .AVIATION /08Z SUNDAY THROUGH THURSDAY/... Through 06Z Monday...Showers continue near the International Border and will sink south through the morning hours. These showers have occasionally presented MVFR conditions with visibilities dropping below 6 miles briefly but have generally remained well above 6 miles. A brief period of MVFR ceilings may occur just behind the front but overall VFR conditions are expected through this TAF Period. Light and variable winds this morning will switch to the NW following the frontal passage at 5-10 knots. Outlook... Monday: VFR. NO SIG WX. Monday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Tuesday: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Tuesday Night: Mainly VFR, with local MVFR possible. Chance SHRA, Slight chance TSRA. Wednesday: Mainly MVFR, with areas VFR possible. Chance SHRA, Slight chance TSRA. Wednesday Night: MVFR/IFR conditions possible. Chance SHRA. Thursday: Mainly MVFR, with local IFR possible. Likely SHRA, Slight chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Clay NEAR TERM...Clay SHORT TERM...Kremer LONG TERM...Kremer AVIATION...Clay