469 
FXUS61 KBTV 171131
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
631 AM EST Tue Nov 17 2020

.SYNOPSIS...
A cold front will cross the area today into this evening along 
with variable clouds and scattered flurries, mainly across 
higher terrain. Expect a chilly day on Wednesday behind the 
front, after which temperatures moderate considerably by 
Thursday into next weekend as south winds return. The next 
chance of significant precipitation occurs by Sunday night into 
Monday.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
As of 630 AM EST Tuesday...The forecast remains largely in good
shape as of 600 am. I did put in a 1-3 hour window of higher 
shower chances through late morning across central/northern 
counties along a pre-frontal convergence line dropping southward
this morning, evident as a line of snow showers across 
northeastern NY into the northern Champlain Valley and portions 
of nc/ne VT. Within this band, brief visibility restrictions to 
below 2 miles are likely, though with sfc temperatures aoa 
freezing little to no impacts are expected. Otherwise, just some
minor cloud coverage adjustments were made to line up with 
current observational trends. Have a great day!

Prior discussion...
Variable clouds will be the rule over the next 36 hours as a 
cold front crosses the region. Deeper moisture is lacking with 
with this feature, so only low to slight chance PoPs (10-30%) 
will be offered today with any minor accumulations occurring in 
elevated terrain (< 1 inch). High temperatures to hold steady 
this morning (30s to around 40), then slowly fall this afternoon
as flow veers northwesterly over time behind the boundary.

By tonight the front clears well south and east of the area. 
However, models generally concur that ample moisture in the lower to 
mid levels will become trapped beneath a building synoptic inversion 
near 850 hPa. As such, while the broad valleys will likely trend 
partly cloudy, higher terrain will likely hold on to ample cloud 
cover with some scattered flurry activity here and there owing to 
the above reasoning and some lightly forced orographic effects. This 
appears reasonable given this is a common occurrence during post-
frontal northwest flow regimes and current upstream clouds across 
southern Canada. Given the expected cloud cover I ended up raising 
minimum temperatures by 1-3 degrees in our colder northern mountain 
locales. 

Then variable clouds/mtn flurries thin/end by Wednesday morning, 
with partly to mostly sunny skies expected by afternoon as high 
pressure builds eastward. This will be the coldest day of the week 
with mean 925 hPa temps hovering only around -10C supporting highs 
only in the 20s to locally around 30.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY/...
As of 250 AM EST Tuesday...Last chilly night in store for the 
short/extended period on Wednesday. Temperatures should drop 
pretty rabidly for the 1st half of the night before clouds and 
southerly winds increase after 06z. Hollows across the 
Adirondacks and eastern VT will see the coldest readings in the 
upper single digits/low teens, with mid teens to around 20 
elsewhere. As warm front begins to push northward expect cloudy 
skies throughout the day Thursday. Temperatures will be near to 
slightly below normal from west to east, with warmest readings 
across the St Lawrence Valley (mid/upper 40s) and coolest 
readings (mid/upper 30s) for far eastern VT/Northeast Kingdom. 
Despite fairly normal readings, southerly winds will increase 
during the day Thursday around 10-15 mph (20-25 mph over Lake 
Champlain) which will make for chillier conditions.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 250 AM EST Tuesday...Overall, relatively quiet period of 
weather through the weekend. Zonal flow aloft will continue to 
bring several impulses across the North Country, however expect 
only an increase in cloudiness as available moisture is lacking.
Surface boundary begins to sink south of southern Quebec 
Saturday. A few sprinkles may be possible with this boundary, 
but expect largely dry conditions. Near to slightly above 
seasonable temperatures in the mid 40s/low 50s are expected 
Friday - Sunday. Our next system begins to approach from the 
west Sunday, with breezy southerly winds increasing throughout 
the day. Surface cold front moves through Monday 
morning/afternoon. P-type is looking like rain at this point 
outside the highest terrain with a chance for some scattered 
snow showers late Monday night as surface front pulls away to 
the east.

&&

.AVIATION /12Z TUESDAY THROUGH SATURDAY/... 
Through 12Z Wednesday...Mainly VFR expected over the next 24 
hours as cold front crosses the region this afternoon. BKN/OVC 
cigs generally in the 035-070 AGL range expected through through
the period, with some occnl partial breaks at favored terminals
of KMSS and KPBG. Scattered flurries likely through much of the
forecast period in higher elevations/KSLK with a brief 1-3 hour
window of MVFR/brief IFR -shsn possible at KSLK/KPBG/KBTV/KMPV 
through late morning/early afternoon as front passes. Winds 
generally west to southwest 5-9 kts through 16Z, trending west 
to northwesterly 6-12 kts thereafter behind the front.

Outlook...

Wednesday: VFR. Chance SHSN.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Saturday: Mainly MVFR, with areas VFR possible. NO SIG WX.

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.

&&

$$
SYNOPSIS...JMG
NEAR TERM...JMG
SHORT TERM...LaRocca
LONG TERM...LaRocca
AVIATION...JMG