textproduct: Burlington

WHAT HAS CHANGED

As of 231 AM EDT Sunday...

No significant changes with this forecast package.

KEY MESSAGES

As of 231 AM EDT Sunday...

1. Periods of rain will make for a wet rest of the holiday weekend. Cool temperatures today will give way to warmer conditions on Memorial Day.

2. Warmer weather expected for mid week, with another chance of showers on Wednesday.

3. Below normal temperatures and some showers are expected at times late in the week.

DISCUSSION

As of 231 AM EDT Sunday...

KEY MESSAGE 1: Hope everyone was able to get outdoors and enjoy the beautiful weather on Saturday as today will be drastically different. Weak low pressure centered over the Great Lakes will slowly push eastward through the day, eventually passing overhead or just to our south tonight into early Monday. A swath of light to occasionally moderate rain associated with warm air advection ahead of the low is currently spreading over our region early this morning, and it will continue to trek eastward through the morning hours. Hourly rainfall amounts have generally been just a few hundredths at most, but do note some locations near Lake Ontario have picked up closer to 0.20 inch in locally heavier showers. Expect this trend will continue as this precipitation moves through northern NY and VT: steady light rain occasionally picking up to become a little heavier at times. The rain and abundant cloud cover will also serve to keep temperatures much cooler than yesterday. The latest surface observations show most places are in the mid 40s to mid 50s at this early hour, and don't expect this will change all that much through the day, with just a few degrees of warming expected. Winds will be blustery as well; a 45kt S/SE 850mb jet will lift across the area, and while mixing won't be optimal due to the steady rain and an inversion around 3000-4000 ft, still anticipate gusts of 20 to 30 mph will be possible across much of the area. Favored northern/western slopes of the northern Adirondacks and Green Mountains could see gusts around 40 mph at times due to downsloping, but expect these will be fairly localized.

The main area of rain exits by mid afternoon, leaving a few lingering showers into the early evening hours. However, another slug of steady rain will move in overnight into Monday morning as the occluded front follows behind the weak surface low. Forcing and moisture will both be a little better with this boundary than what we're seeing this morning. The front may also become oriented parallel to the flow for a time as winds turn more toward the S/SW, which may lead to some training of cells. All this points toward tonight seeing higher rainfall amounts than today. Rainfall amounts through the day today will range from just a few hundredths in the Northeast Kingdom (due to shadowing from the Whites), to around a half an inch in the Adirondacks and southern St Lawrence Valley. Tonight into Monday, meanwhile, expect a widespread third to half an inch of rain, with some spots seeing up to three-quarters of an inch. Rainfall rates will be moderate at times but not enough to cause any flooding concerns beyond perhaps some ponding in poor drainage areas. The rain comes to an end from west to east quite quickly Monday afternoon, and expect we'll see the sun poke out by evening. Highs will be much warmer than today, seasonably in the mid 60s to mid 70s.

KEY MESSAGE 2: High pressure will build across the Northeast CONUS Monday night and Tuesday, giving us a break from the wet weather. A cold front will start to approach from the north late in the day Tuesday, but don't anticipate much more than increasing clouds through the daylight hours. Flow will turn toward the southwest, and this with sunshine will allow highs to warm into the mid 70s to low 80s. Winds will pick up a bit ahead of the incoming front, so it might be a little breezy later in the day, especially in the Champlain and St Lawrence Valleys and along the northern slopes of the Adirondacks.

The front moves through Tuesday night into Wednesday as the surface low passes by well to our east. As is usually the case, the front will move through rather piecemeal, with a wind shift/surface trough coming through early Wednesday, followed by a temperature/moisture gradient later Wednesday. Either way, with meager forcing and moisture, don't expect much more than a round or two of scattered showers. While instability doesn't look very impressive, can't totally rule out a rumble of thunder or two Wednesday afternoon with the secondary front. Wednesday will be a little cooler than Tuesday, mainly in northern areas, but it will still be warm with highs in the low 70s to around 80F.

KEY MESSAGE 3: No significant weather is currently anticipated Thursday through Saturday. In the upper air pattern, there will likely be a cutoff low over the western US and large ridge downstream over central North America. This pattern will support northwest flow and cool weather in the North Country and New England, with potential for showers when any shortwaves of polar origin push through our area. The predictability of how these fast moving systems progress is very low at this time, so it is impossible to say when and where showers will occur. That being said, the blend of models suggests Friday during the daytime hours is our greatest opportunity for seeing some rain and most unseasonably cool conditions. High temperature spread on both Friday and Saturday are greater than typical, owing to the uncertainty in how anomalous of a cool air mass will be present and associated cloud cover/rain. Needless to say, the current forecast highs could trend substantially cooler on either or both days as predictability increases moving forward.

AVIATION /06Z SUNDAY THROUGH THURSDAY/

Through 06Z Monday...VFR conditions prevail as light rain begins to overspread the airspace. Pockets of moderate rainfall rates will support some MVFR visibilities, while ceilings remain largely above 3000 feet through 12Z. Thereafter, MVFR conditions may gradually develop at all terminals as ceilings lower slightly, perhaps with exception of EFK with greater moisture/rainfall staying farther south and west. Steady rain will shift south and east of the region between 18Z and 21Z, although another round of showers will likely move in from the southwest towards the end of the TAF period and help to sustain MVFR potential. Winds are somewhat tricky through the period as a moderately strong southeasterly low level jet gradually lowers and shifts slowly northeastward through the region. Light and locally southerly winds currently should trend southeasterly and gusty after 09Z with periodic gusts of 20 to 30 kts at most sites, although this pattern will keep winds at MSS mainly lighter out of the east/northeast for most of the period. Most sites should be experience some LLWS, with the most persistent and strong shear expected at SLK and RUT. By 00Z, additional LLWS should be focused across eastern Vermont such that MPV and EFK will be favored.

Outlook...

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

MARINE

As of 231 AM EDT Sunday... A Lake Wind Advisory is in effect for today. South to southeast winds will increase early this morning, becoming sustained 15 to 25 kt with gusts to 30 kt. Waves will be 1 to 3 feet.

BTV WATCHES/WARNINGS/ADVISORIES

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