FXUS61 KBTV 170536
AREA FORECAST DISCUSSION
National Weather Service Burlington VT
136 AM EDT Wed Jul 17 2019
An advancing cold front will bring showers and thunderstorms to
the region on Wednesday. Moisture from the remnants of tropical
system Barry interacts with this front dropping down from
Canada. Heavy rainfall is possible which could lead to localized
flooding. The front moves south of the area Wednesday and drier
air moves in for Thursday. The pattern will change once again
Friday and Saturday experiencing hot and humid conditions along
with the threat of thunderstorms, some of which could be strong
.NEAR TERM /THROUGH TONIGHT/...
As of 135 AM EDT Wednesday...Overall forecast in good shape.
Increasing clouds with increasing chances for showers is the
main idea and handled well in the forecast. Only tweak is to low
temperatures as temperatures will stay up overnight with all the
clouds moving in...but some areas of eastern Vermont have
cleared out and fallen to expected lows. So have fine tuned
temperature trends over the next several hours to match this
Forecast for tonight is in good shape with dry conditions for
evening activities. Light south to southwesterly flow continues
to increase 2-m dewpoints across the North Country, with
readings generally in the 65-70F range. Muggy conditions will
prevail overnight, with lows generally in the mid 60s east of
the Green Mountains, and in the upper 60s to lower 70s across
western VT into nrn NY. Weak shortwave ridging and absence of
low-level convergence will keep shower chances low (around 20%)
through 06Z or so. However, it appears that a weak shortwave
trough moving enewd from nrn OH and srn lower Michigan will
bring an increasing threat of showers during the pre-dawn hours
Wednesday. CAPE is limited, so maintained just a slight chance
of thunderstorms overnight. Best chance of showers late tonight
will be across nrn NY into the Champlain Valley.
Potential for showers will continue to increase across the
region through Wednesday. Most precipitation falls from 09-18z
Wednesday. Greatest pwats over the area will be in the Champlain
valley where numerical guidance is surpassing 2" pwats.
Widespread showers and isolated thunderstorms are expected,
greatest threat for heavy rain will be across our most southern
zones in Vermont. Some of this moisture is related to the
remnants of tropical storm Barry, some threat for heavy rainfall
continues, though areas to our South are even more threatened.
Storm total rainfall from tonight through tomorrow range from
around a quarter of an inch along the international border up to
about an inch in Southern Vermont. Daytime high temperatures on
Wednesday will be near normal, generally upper 70s to lower
80s. Showers will shut down pretty quickly after 00z Wednesday
evening as cold front continues to push eastward, along with
deepest low level moisture. A surface high will be on it`s heels
and ridging into our area out of Canada for Wednesday night.
Minimum overnight temperatures will be around seasonal normals
as well, generally upper 50s to around 60.
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 322 PM EDT Tuesday...Thursday will be an overall nice day on
the back side of the front that swings through on Wednesday. Deep
layer ridging develops through the day on Thursday which will yield
some clearing of skies, especially across the northern half of the
forecast area. However, this ridging will be very transient will
already be exiting to our east by late Thursday. Temperatures will
be seasonable with highs in the upper 70s to mid 80s, however
dewpoints in the mid 60s could make it feel a little uncomfortable
Thursday afternoon and evening.
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 322 PM EDT Tuesday...The main story Friday and heading into the
weekend will be some impressive heat and the potential for strong to
severe thunderstorms. A warm front will lift across the North
Country Friday morning which will also begin ushering in yet another
moisture rich air mass. The warm front should pass through the
region uneventfully with very little shower activity expected with
the antecedent dry air ahead of the front. Strong warm air advection
is noted on all numerical guidance on Friday with 850 mb
temperatures warming from 16 degrees C near sunrise to 21 degrees C
by late afternoon/early evening. This should yield afternoon high
temperatures warming into the mid 80s to lower 90s. As mentioned
earlier, moisture will also be surging into the region on Friday.
Dew points will easily increase into the low 70s with the
possibility of mid 70s across the St. Lawrence Valley. This will
create heat index values of 95 to 105 across the Champlain and St.
Lawrence Valleys with lower 90s elsewhere. Should this scenario
continue to look likely, a heat advisory will be needed in the
coming days. In addition to the heat on Friday, some strong
thunderstorms will also be possible. Anytime temperatures warm into
the 90s with dewpoints in the 70s, pulse thunderstorms are always a
possibility. Given the drier air initially on Friday and equilibrium
levels above 45,000 ft, any storms that pop up would have the
potential to drop some gusty and possibly damaging winds.
Saturday will see a continuation of heat with a cold front now not
expected to push through until the late afternoon hours. High
temperatures will be range from the upper 80s to mid 90s with
dewpoints once again in the 70s. Heat index values for Saturday will
also range from 95 to 105 with the same locations mentioned earlier
possibly needing a heat advisory. Otherwise, Saturday could be an
active day for strong to severe thunderstorms. Instability,
moisture, shear and lift will all be present. Shear overall looks
pretty meager with 0-6 km shear around 30-35 knots but instability
upwards to 2000 J/kg is more than enough to help storms get
organized. In addition, the aforementioned cold front will act as a
lifting mechanism to help storm initiation. As typical in North
Country fashion, trying to get the front and trough to line up
remains in question which could either help our hurt the chances for
severe weather on Saturday depending on if they are in phase or not.
A big pattern change will begin to take place on Sunday and continue
into Monday as an upper level trough begins to amplify to our west
before moving overhead late Monday. This will drive another front
through the region sometime Sunday night into Monday afternoon
depending on which model you believe. Significantly cooler (and
drier!) air is expected underneath this trough which looks to stall
out over us through at least the middle of next week with
temperatures trending back to near normal or possibly even below
normal. Showers will remain possible pretty much every day in the
upcoming week with broad cyclonic flow aloft but the lack of any
major storm system will prevent any particular day from being a wash-
.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
Through 06Z Thursday...A mix of MVFR/VFR through the TAF period
as remnants of Barry begin to move into the North Country.
Deck of high clouds will begin to lower through the night with
ceilings becoming MVFR by 12z. Rain showers and potentially
some thunderstorms will develop after 10Z. Expecting mostly
MVFR visibilities in these showers, however locally IFR may be
possible in heavier showers/thunderstorms with best chances at
KRUT and KMPV terminals. Winds during this time frame will be
generally out of the south between 5-10 knots. A cold front
sags south from Canada towards 22z bringing with it improved
conditions on northwesterly/northerly winds between 5-8 kts.
Thursday: VFR. Slight chance SHRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Chance SHRA, Chance TSRA.
Friday Night: VFR. Chance SHRA, Chance TSRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA,
Saturday Night: Mainly VFR, with local MVFR possible. Chance
SHRA, Chance TSRA.
Sunday: VFR. Chance SHRA.