FXUS61 KBTV 250230
Area Forecast Discussion
National Weather Service Burlington VT
1030 PM EDT Thu May 24 2018
Expect more sunshine on Friday along with above normal
temperatures as gusty west to southwest winds develop. Highs
will be in the upper 70s to mid 80s. The potential for showers
will increase along the Canadian Border Friday night as a cold
front moves southward into the region. This boundary will
continue to move south across the area on Saturday with the
threat of more showers and a few thunderstorms expected across
northern New York and northern and central Vermont. Showers will
come to an end later Saturday night and it now looks like the
best chance for any precipitation on Sunday will be out across
portions of northern New York where a cold front becomes
established. This front will move slowly eastward on Memorial
Day and thus there will be a continued chance for precipitation
across the entire North Country.
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 1028 PM EDT Thursday...Only minor adjustments to the
forecast at this time...primarily to lower temperatures
overnight with excellent radiative cooling ongoing. Dry weather
will continue tonight with little in the way of any cloud cover
as high pressure continue to prevail over the region. Low
temperatures generally in the low to mid 50s. Some of the
normally cooler spots within the northern Adirondacks and far
nern VT will see overnight lows in the mid to upr 40s.
Idea of above normal temperatures for Friday looks real good
with pronounced west to southwest flow becoming established.
Highs will be in the upper 70s to mid 80s. Could be looking at
another day of large temperature-dew point spreads with
afternoon relative humidities getting down into the 20 percent
range in some areas. We were able to get down into the 10
percent range today. So with a bit more wind on Friday will need
to keep an eye on potential fire weather concerns. We are
greening up which may help mitigate concerns just a bit...but
something to definitely keep an eye on. There should be some
convection up across Quebec that wants to move east-southeast
toward our area...but feel most of it will remain north of the
border Friday afternoon.
Cold front moves slowly south into the region Friday night and
feel this will be when the northern and central sections of our
area have the best chance of experiencing any showers and maybe
a thunderstorm near the international border in the evening.
Higher dew points...clouds... and showers should keep lows in the
mid 50s to mid 60s.
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 338 PM EDT Thursday...Cold front continues to sag slowly
southward during the day on Saturday and weakens with time.
Nevertheless it will be a focus for convection Saturday
afternoon as instability develops along and south of the
boundary and precipitable water values increase. Best chance for
showers and possibly some thunderstorms will be across northern
New York and the central and southern sections of Vermont.
Saturday night the front washes out and the flow turns more west
and southwest. Thus any lingering showers should move back east
and northeast before weakening as it encounters more stable
air...which is in response to a developing maritime flow as high
pressure builds down and creates a more easterly component to
the low level flow. Should not see much in the way of
precipitation overnight...but would expect plenty of clouds and
maybe some fog. Lows Saturday night should be in the upper 40s
to upper 50s.
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 338 PM EDT Thursday...Complex and dynamic upper level and
surface pattern prevails across our forecast on Sunday into
Monday with backdoor front draped over our cwa. This front will
result in a sharp west to east thermal/instability axis and make
for a challenging pops forecast for Sunday into Monday.
NAM/GFS/ECMWF show best combination of instability, moisture,
and lift/convergence across northern NY/SLV therefore have
mention likely pops with thunder in this region and just chc of
showers cpv/central and eastern VT zones. Have noted pws btwn
1.50 to 1.75", CAPE values of 1000 to 1500 j/kg, and good se to
sw convergence across the slv/western dacks where boundary
becomes stationary. While the shear is limited with 0 to 6 km
values of 25 to 30 knots, thinking localized very heavy rainfall
is possible across the SLV/Western Dacks on Sunday
aftn/evening, given the cape/pw profiles, along with vector
analysis showing some potential for training/back building
storms. Sharp qpf/pop gradient anticipated with much
drier/stable maritime airmass from CPV eastward. Progged
850/925mb temps with boundary overhead support highs lower 80s
west to upper 60s to mid 70s east...with 75f at BTV.
On Monday...surface boundary dissipates across our cwa as surface to
925mb flow becomes southerly and west/northwest flow aloft develops.
This southerly winds will help to advect some additional
moisture/instability across our central/western cwa on Monday aftn.
This will interact with s/w energy dropping down in the flow aloft
with an approaching cold front to produce additional chances for
showers/storms. Best chc for storms will be along and west of the
cpv...where cape profiles approach 1000 j/kg. Progged 850mb temps
near 14c support highs in the mid/upper 70s with maybe a few lower
80s possible in the warmer valleys. The overall threat for
stronger/severe storms looks limited do to the lack of
shear/instability, but if more sfc heating and moisture can develop
a few stronger storms are possible on Monday afternoon.
As front clears the area overnight Monday Night into early Tuesday,
clouds will linger but taper off relatively quickly as dry air moves
in after 12z. Expect clear sunny skies by the afternoon on Tuesday
with temperatures in the mid to upper 70s. Pressure gradient
remains relatively strong, and with good daytime mixing, could
have some breezy conditions during the day Tuesday. Surface high
pressure builds in by Tuesday night, thus expect clear and calm
conditions overnight. Good radiational cooling is likely so
have low temperatures at or slightly below normal (normal this
time of year is around 48) with mid 30s in the Adirondacks and
mid to upper 40s in the Champlain valley and points east. High
pressure and dry air remain in place through Wednesday before
our next system approaches from the west on Thursday. This
system is relatively complex with timing of upstream shortwave
and the phasing of the potential tropical system over the
southeast US playing an important role in it`s develop. Models
overall agree on some phasing of these systems, but diverge on
the timing and placement of the heaviest moisture, with GFS
indicating higher moisture and rain chances towards the end of
Thursday, and ECMWF holding off until early Friday morning with
heaviest precip over mid Atlantic. At this time have gone with
Superblend of PoPs between 20-40 to indicate uncertainty but
possibility of unsettled weather for the end of the period.
Temperatures through this time will likely be above normal with
highs in the upper 70s to around 80 and lows in the upper 50s to
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Through 18Z Friday...VFR thru the period. Will see widespread
LLWS 03-12Z as westerly low-level jet develops with winds
35-45kts at 2kft AGL. Have included LLWS for all TAF locations.
Sfc winds SW...increasing to 10-15kts on Friday with gusts
20-22kts at BTV/SLK/PBG/MSS. Mid-level clouds will increase
Friday afternoon (SCT-BKN080-150) with a slight chance of a late
afternoon shower at KMSS.
Friday Night: VFR. Chance SHRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
Saturday Night: Mainly VFR, with local MVFR possible. Chance
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA, Likely
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Memorial Day: Mainly VFR, with areas MVFR possible. Chance SHRA,
Monday Night: Mainly VFR, with local IFR possible. Chance SHRA,
Slight chance TSRA.
Tuesday: VFR. Slight chance SHRA.