textproduct: Burlington

WHAT HAS CHANGED

As of 259 PM EDT Saturday...

Air quality impacts no longer expected today/tonight.

KEY MESSAGES

As of 259 PM EDT Saturday...

1. Showers and an isolated thunderstorm will gradually wind down by sunset in southern portions of our region.

2. Seasonable and dry conditions early in the week. We'll be watching the northward extent of an area of heavy rain over southern New England, which could come far enough north to affect southern portions of Vermont.

3. Warm and somewhat humid for mid and late next week with a couple shower chances.

DISCUSSION

As of 259 PM EDT Saturday...

KEY MESSAGE 1: A very weak disturbance aloft well to our west coupled with a sharp moisture gradient across northern New York and northern Vermont is promoting a southward shifting area of showers today along a surface cold front. The front is more of a dew point front, with sharply drier air lagging a few hours but it is on its way with refreshing air (dew points approaching 50 degrees) incoming on breezy northerly winds.

The showers south of the boundary are producing a couple of thunderstorms as of this hour. The chance of a thunderstorm remains low but non-zero through this evening, although the risk area will continue to shrink towards the south. Thankfully for outdoor activities, even when showers grow tall enough to produce lightning, storms will be quite weak given an environment with low downdraft CAPE (under 500 J/kg) amidst similarly low mixed layer CAPE, such that risk of strong winds or hail is minimal. The marginal instability will likely trend lower as drier air near the surface advects in simultaneous with the ongoing convection, so would not expect an uptick in thunderstorm chances towards the evening.

KEY MESSAGE 2: Tranquil weather will prevail tonight through at least Monday morning areawide, associated with a wedge of deep layer ridging in place north of the cold front as it settles well to our south. The next chance of rain begins Monday with a fairly uncertain forecast of rainfall chances throughout the period from Monday through Wednesday, tied to the northward progress of an anticipated slow moving wave of low pressure along a quasi-stationary front. This system will have the ingredients for very heavy rainfall amounts, and an excessive rainfall outlook currently is in place to our south where the consensus footprint is located.

Rainfall amounts and chances for any measurable rain taper off sharply moving northward from southern Vermont and southern Adirondacks. The northward extent currently peaks early Tuesday, although the wetter/farther north scenarios lead to a later timing of the rainfall. The wettest guidance shows significant rainfall is possible across our region, and have noted some of the latest deterministic guidance shows the footprint of heavy rain extending into southern Vermont. We'll watch these trends closely given the potential impacts. At this time we have tilted sky cover a bit towards mostly cloudy skies progressing northward on Tuesday, and if trends in the data suggest a more northward footprint of deep moisture and rain we will see cloudy skies along with temperatures trending cooler in the coming days. High temperatures will be heavily dependent on the position of the front; if it tends to be farther south, we'll see less moisture/precipitation leading to highs in the 80s, while more northward location will support wetter conditions leading to temperatures mainly in the 70s but with higher humidity.

KEY MESSAGE 3: A cold front will eventually pass through late next week, likely late Thursday or Friday. Out ahead of it, the heat and humidity will gradually build. By Thursday, temperatures will likely reach the mid 80s to lower 90s. Dew point will gradually rise well into the 60s. However, the airmass will be less warm than last week and its residence time will be shorter, so there will be less time for the heat to build in from the southwest. Showers and storms should accompany the cold front, and the potential for strong to severe storms will be watched as its exact strength and timing become more certain. Behind the front, a drier and somewhat cooler airmass looks to persist into mid-July.

AVIATION /00Z SUNDAY THROUGH THURSDAY/

Through 00Z Monday...The last few showers are shifting south of KRUT at this time. Skies will trend mostly clear overnight with winds quickly becoming calm or terrain driven. On one hand, dry air is shifting into the region with a front now to our south, but it will also be cooler with a better opportunity to radiate than the last several days. For now, depicted fog in TEMPOs for fog favored terminals and decided to include KRUT since it rained there within the last hour, mostly 06z-10z. Winds favored some prevailing fog at KMPV, but remained optimistic with 3SM through 12z, but it could easily dip towards IFR. Otherwise, after 12z, mainly fair weather cumulus at or above 7000 ft is expected with northwest winds around 5-9 knots.

Outlook...

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

BTV WATCHES/WARNINGS/ADVISORIES

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