textproduct: Burlington

WHAT HAS CHANGED

As of 145 AM EDT Sunday...

No significant changes were made to the forecast.

KEY MESSAGES

As of 145 AM EDT Sunday...

1. Showers continue this morning before tapering off with clearing skies this afternoon and evening. Ridging begins to build into the region tonight into the start of next week with warm and drying conditions.

2. Warm, humid conditions could pose heat risk concerns along with chances for showers and thunderstorms.

DISCUSSION

As of 145 AM EDT Sunday...

KEY MESSAGE 1: Nearly geostrophic cyclonic flow around an occluding upper low over southern Quebec will keep showers rotating through the region early this morning into early this afternoon. Persistent showers on the southern flank of the low combined with decent pwats to an inch, and rain rates to a quarter inch an hour at times, will bring an additional quarter to half an inch of rain to the region today, mainly near the International Border and the higher terrain. The low will pivot southwards this morning as high pressure across the Great Lakes increases the northerly steering flow aloft. As the lows sinks south, a band of light to moderate showers will develop near the International Border and slide south. Shower chances with this band are between 75-100% generally between 9 AM and 3 PM from north to south. Areas in the Northeast Kingdom and the northern Champlain Valley will likely stay under light shower and mist activity for several hours before the band shifts south. Northerly winds may gust up to 20 to 25 MPH in the Champlain Valley and eastern Vermont as the low pivots south with a continued tighter pressure gradient. Northerly flow will advect cooler air from the north behind the rain band with highs today 10 degrees cooler than yesterday into the mid to upper 60s. Skies will quickly begin to clear as rainfall tapers off by mid to late afternoon. High pressure from the west will help trends winds towards calm with clearing skies under light north northeast flow aloft. Northeast flow in the St. Lawrence Valley with cooling temperatures may lead to patchy fog along the river for locations such as Massena and Ogdensburg tonight. Similarly, where flow is lighter in the protected valleys, the NEK may also experience some patchy fog. Elsewhere light flow aloft should keep fog chances low.

Into the work week, mid and upper level ridging will build in from the west through at least Wednesday. Ridging will support increasing temperatures and dry conditions for early to mid next week. 925mb temperatures in the latest ensembles are progged to be around 20C, supporting surface temperatures in the 80s both Monday and Tuesday. Temperatures will steadily climb each day Monday into Tuesday with each seeing daytime highs a degree or two warmer than the last. Dewpoints Monday and Tuesday will be in the 50s, leading to comfortable humidity values and generally cool overnight lows in the mid to upper 50s as well.

KEY MESSAGE 2: Forecast conditions from Wednesday onwards remains unchanged. As has been the weather pattern the last several days, a high amplitude ridge will bring some warm to hot temperatures. Then, a trough on its northern periphery will get shunted southeast. Of all these types of systems, this will be the weakest in terms of baroclinicity. Rain will overspread the region late Wednesday into Thursday as the weak surface low tracks off the Maine Coast. However, unlike the last several occasions, the ridge doesn't just reamplify to our west, but begins to angle east as a longwave trough takes its place. Given its breadth, the large upper low positioned near the Hudson Bay will be slow to move. Deep southwesterly flow with a connection to the Gulf will let increasing warmth and humidity spill into the region. There will be a some bifurcation of instability as surface high pressure across the Canadian Maritimes drives in more stable southeasterly flow. So any thunder chances will be greatest for northern New York. With temperatures in the upper 80s to lower 90s and dewpoints climbing into the 60s, we'll have the potential to observe heat indices close Heat Advisory thresholds. We've had heat this year, but this will be the first with increased humidity. So heat-health concerns will be present with the probability of reaching the Major (Level 3 of 4) category around 50-70% across lower elevations.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Through 06Z Monday...Rain is present over the region with mainly VFR or MVFR conditions, though there are patches of IFR noted near KSLK and KEFK. Conditions will probably hold steady for the next 2-4 hours as rain shifts east, and then as the surface low moves farther southeast from Vermont, winds will become west to northwest at 5-11 kts with some gusts 16-20 kts. At 2000 ft agl west-northwest winds remain about 35-40 knots, which will cause pockets of LLWS over KEFK and KMPV for the next few hours. Then from about 10z-18z, rain will wrap around the surface low back southwards. Ceilings will lower to 700-2100 ft agl, with IFR ceilings likely at KSLK and KEFK, but also possible at KBTV. Behind this push of rain, winds will become northerly, and then ceilings will quickly improve behind rain. After 00z, winds will begin to decrease with skies trending clear. The only thing will be a northeasterly low-level jet with winds at 2000 ft agl around 35-40 knots, which will produce LLWS at KEFK and perhaps KMPV. These winds will arc south beyond 06z Monday.

Outlook...

Monday: VFR. NO SIG WX. Monday Night: VFR. NO SIG WX. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Slight chance SHRA. Wednesday: VFR/MVFR conditions possible. Chance SHRA, Slight chance TSRA. Wednesday Night: Mainly MVFR, with areas IFR possible. Chance SHRA, Slight chance TSRA. Thursday: MVFR/IFR conditions possible. Chance SHRA, Chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

VT...None. NY...None.