textproduct: Burlington

WHAT HAS CHANGED

As of 225 PM EDT Monday...

Patchy dense fog has been added to the forecast in favored valley locations for midnight tonight thru approximately 8am Tuesday.

KEY MESSAGES

As of 225 PM EDT Monday...

1. Patchy dense fog tonight into early Tuesday morning.

2. Scattered showers with a few thunderstorms possible Wednesday.

3. After a stronger system on Thursday, cool and showery conditions will prevail late this week and over the weekend.

DISCUSSION

As of 225 PM EDT Monday...

KEY MESSAGE 1: Generally quiet weather conditions anticipated over the next 36 hours (thru Wednesday morning). A narrow zone of surface high pressure cresting over the North Country overnight will bring light and variable wind conditions after midnight. Ongoing areas of stratocu in low-level CAA (and trapped beneath a sharp inversion layer) will persist into this evening, but are also expected to dissipate toward midnight. Given widespread rainfall that occurred on Sunday/Sunday night, conditions are favorable for patchy dense fog, especially in the favored river valleys. Fog should persist through 12-13Z Tuesday before dissipating. Overnight lows are generally expected in the mid 40s to lower 50s, except locally in the upper 30s across the northern Adirondacks.

KEY MESSAGE 2: A modest shortwave trough is expected to shift northeastward into nrn NY and VT mid-late Wednesday afternoon into Wednesday evening. Should see partly sunny conditions for the balance of the day, but with an increasing chance for scattered showers during the afternoon and evening hours. Weak surface-based CAPE up to 750 J/kg may allow for a few embedded thunderstorms, though severe storms are not expected. Afternoon high temperatures may be a few degrees warmer than Tuesday, generally reaching the mid- upper 70s, and a few lower 80s in the Champlain and Upper Connecticut River Valley. South winds increasing to around 10 mph in the afternoon will allow dewpoints to climb into the mid-upper 50s late in the day.

KEY MESSAGE 3: An impressive mid-June system will track along and north of the St. Lawrence Valley on Thursday. Buoyed by mid-level instability and a 120 knot jet streak to our southwest, this warm front will have excellent lift. 850mb winds of 50-55 knots will produce strong moisture advection through the region. A solid shield of rain will race northeast through our forecast area in 4-6 hours on Thursday morning. Thereafter, the intense sub 990mb surface low will pass along Montreal during the afternoon with the occlusion shifting east about noon-8pm. Convergence along the front will be good, and there will about some instability and below normal temperatures aloft. We will likely see convection, but equilibrium levels will be around -12 C, which suggests short and stout activity that may struggle to produce thunder with general lack of cloud ice. Still, we'll keep an eye, as there will be plenty of wind in the low- levels, but the strong shear may inhibit lift, in addition to dry air in the warm section. Some guidance has activity redeveloping, while others keep things limited, and so time will tell. Given the strong, but fast, nature of the front, and then some convection, there should be roughly 0.33-0.67" of precipitation with localized amounts around 1-1.25".

Precipitation will begin to gradually clear the area on Thursday night as a large upper low spirals to our north. It won't really budge for several days. So intervals of scattered rain showers will shift southeastwards across the region for the latter part of the week. If any day were to have thunder, it might be Friday with somewhat higher instability, cool temperatures aloft, and a weak surface trough passing through together. By next Sunday into next Monday, the upper low will begin to open into a trough and slide eastwards. As is typical for seven days out, models begin to sharply diverge, but things are leaning on the cool, showery side.

AVIATION /18Z MONDAY THROUGH SATURDAY/

Through 18Z Tuesday...Stratocumulus clouds have been a little more persistent than anticipated. KSLK also has a lower layer of SCT007 as a subtle area of vorticity coming off Lake Ontario has kept clouds, lower ceilings, and a few showers nearby. This feature is dissipating, but the chance for a few showers and intervals of 1200-2000 ft agl ceilings will still be present for a little longer. West to northwest winds of 6-12 knots will prevail for the next few hours, and then gradually subside between 23-02z towards light and variable. Clouds will begin to scatter overnight. Although patchy high clouds will be possible overnight, the recent rainfall and modest radiational cooling with dry mid-levels and light surface winds should allow some valley fog. There's some 15-25 knot winds hovering near 500-1000 ft agl, and this may limit activity. This may also result in areas of localized LLWS, but is not noted at any particular terminal. For now, 3SM is noted at just KSLK and KMPV still from roughly 07z-12z. After 12z, southwest to west-northwest winds pick up to about 5-9 knots, except for a lake breeze with a southeast wind at KPBG.

Outlook...

Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. Chance SHRA, Slight chance TSRA. Wednesday Night: VFR. Chance SHRA. Thursday: Mainly VFR, with areas MVFR possible. Windy with gusts to 30 kt. Definite SHRA, Chance TSRA. Thursday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Friday: Mainly VFR, with areas MVFR possible. Chance SHRA, Slight chance TSRA. Friday Night: Mainly VFR, with areas MVFR possible. Chance SHRA, Slight chance TSRA. Saturday: Mainly VFR, with local IFR possible. Likely SHRA, Slight chance TSRA.

BTV WATCHES/WARNINGS/ADVISORIES

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