textproduct: Burlington

WHAT HAS CHANGED

As of 216 AM EDT Tuesday...

Forecast precipitation amounts have increased slightly for the Wednesday into Thursday morning system, and the arrival of precipitation continues to trend earlier in the day Wednesday than the previous forecast.

KEY MESSAGES

As of 216 AM EDT Tuesday...

1. Mostly dry and seasonable weather is expected today and tonight, then more widespread precipitation arrives Wednesday into Wednesday night.

2. High pressure will bring another stretch of dry and pleasant weather to start the weekend.

DISCUSSION

As of 216 AM EDT Tuesday...

KEY MESSAGE 1: A dying cold front will come through early this morning and bring a few light showers, but weak forcing and dry low levels will minimize the impacts. Ridging will become more established and dominate the synoptic pattern going into Wednesday, continuing the quiet and relatively seasonable to above normal stretch. Overall, highs will be in the 70s to lower 80s through Thursday. Lows tonight will be in the mid 40s to lower 60s, increasing to the upper 50s to mid 60s Wednesday night with the arrival of a warm frontal boundary attached to a deepening low pressure system in Canada. While warm air advection will bring a more humid airmass into the region, there will not be enough time for a fully tropical airmass to become established. Rain arrives throughout the day Wednesday in northern areas as a warm front pushes through, though it appears to lack much elevated instability, so the rain should just be stratiform. The center of the low will pass by well to the north of our area, and the best dynamics should miss the region. Therefore, this will limit instability as the system passes by. The highest instability will be across the St. Lawrence Valley where the warmer airmass has the most time to become established. Dew points there should briefly reach the mid 60s to around 70 and a few rumbles of thunder are possible there. The cold front passes through Wednesday night into early Thursday, but the warm sector never looks to become fully established in the region, so most convection should remain to the southwest. St. Lawrence County and southern Vermont look to be the places that may see more convective enhancement, while the rest of the region should mostly see synoptically forced rain. However, if the trend of earlier precipitation and a faster system continues, we may see more availability of instability on Wednesday for more widespread thunderstorms. A strong southwesterly low-level jet will reach the 40-55 KT range at 850 mb Wednesday and Wednesday night, causing downsloping in the typical spots like the Champlain Valley, which could limit rainfall totals. Overall expected totals range in the 0.15 to 0.75 inch range for most places, with some higher totals locally along the spine of the Green Mountains and Adirondacks. This jet will also lead to widespread gusts in the 20-30 mph range, with locally higher gusts, particularly on summits. Then Thursday, winds should stay elevated in cold air advection out of the west and northwest.

KEY MESSAGE 2: High pressure will build into the region towards the end of the week into the weekend, bringing a stretch of dry and pleasant weather. Daytime high temperatures on Friday will generally be in the upper 60s and low 70s, with warmer temperatures expected for Saturday and Sunday in the 70s to near 80 as the ridging shifts eastward leading to southerly flow across the region. Ideal radiational cooling conditions are expected, especially Friday night into Saturday morning with the high pressure overhead. Overnight lows are expected to drop into the 40s, with some of the cold hollows dropping into the mid/upper 30s while locations near Lake Champlain will stay in the 50s. While dry weather will persist through much of the weekend, precipitation chances will increase through the day on Sunday with a shortwave trough pushing through, although there is still plenty of uncertainty regarding this feature.

AVIATION /12Z TUESDAY THROUGH SATURDAY/

Through 12Z Wednesday...A weak front continues to push through the region this morning, bringing some light precipitation and lower ceilings. Currently only KEFK is experiencing MVFR ceilings and reduced visibilities, but intervals of MVFR will be possible at several terminals this morning as the shower activity moves through, particularly across more northern locations. Improvement back towards VFR is expected towards 18Z, with VFR continuing through most of the forecast period. Winds will trend north/northwesterly throughout the day today, generally less than 10 knots, before becoming light and terrain driven overnight.

Outlook...

Wednesday: Mainly VFR, with local MVFR possible. Chance SHRA. Wednesday Night: Mainly MVFR, with local IFR possible. Definite SHRA, Slight chance TSRA. Thursday: Mainly VFR, with local MVFR possible. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX.

BTV WATCHES/WARNINGS/ADVISORIES

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