000
FXUS61 KBTV 252338
AFDBTV

AREA FORECAST DISCUSSION
National Weather Service Burlington VT
738 PM EDT Sat May 25 2019

.SYNOPSIS...
A warm front will push into the area this evening with
widespread rainfall expected along with a few non-severe
thunderstorms. Precipitation tapers off for Sunday as a weak
cold front drops through the area and high pressure builds in
from the west. Fair and mainly dry weather continues through
Tuesday before more unsettled conditions return for the later
half of the work week.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 724 PM EDT Saturday...Strong to severe thunderstorms have
developed along a warm frontal boundary across northern New
York. These storms have developed in a relatively stable
environment and should continue to track into an increasingly
stable environment which should cap any severe potential heading
into the overnight hours. Rainfall rates between a tenth of an
inch to a quarter of an inch per hour have been observed with
these thunderstorms and similar amounts are expected as the
storms begin to push into Vermont by 8 PM. Lightning activity
has largely been confined to northern New York and has been
dwindling as the environment continues to stabilize. It looks
like the bulk of precipitation will exit the North Country
shortly after midnight with drier conditions expected Sunday
morning.

Previous Discussion...The forecast remains largely on
track for tonight as a warm front approaches from the southwest
and widespread light to moderate precipitation overspreads the
region. Fairly robust support for pcpn exists with a good surge
of warm advection pushing into the area on the nose of a 50kt
southwesterly mid-level jet. This feature will also usher in an
airmass of higher moisture content (PWATS to 1.5") and steeper
mid-level lapse rates and have maintained non-severe elevated
thunder chances accordingly. This will be most focused across
northern NY where locally heavy rainfall wording will be
maintained generally along and southwest of an Ogdensburg-
Saranac Lake-Ticonderoga line per recent WPC excessive rainfall
D1 guidance. 12-hour model blended QPF maintains consistency
with prior forecasts showing basin average values from 0.50 to
1.0 inches north and from 0.25 to 0.50 inches south, locally
higher to 2 inches in aforementioned heavy rainfall threat area.
At this point the threat of flash flooding in this area is
rather low, but non-zero given 3- hourly FFG is averaging only
around 2 inches. Therefore conditions will be monitored closely
this evening. Most of the steadier pcpn should be focused this
evening through 2 to 3 am or so with coverage generally tapering
off by sunrise as best forcing exits east and south. Lows
tonight on the mild side under persistent southerly flow
- mid 50s to lower 60s.

Any scattered early morning showers to gradually wane through the
day on Sunday as a weak cold front sweeps through the area and
ambient conditions dry out over time. Some lingering instability and
steepening low level lapse rates give me pause to omit thunder
entirely at this point, but the overall theme will be for large-
scale drying and skies trending partly sunny by late morning into
the afternoon. High temperatures to run seasonably mild in the 70s
to locally near 80 far south.

High pressure then builds east from the Great Lakes Sunday night
with mainly clear skies, light winds and nil pops. Lows near
seasonable late May norms in the 40s to around 50.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 336 PM EDT Saturday...A weak boundary will cross the area
Monday morning bringing mainly an increase in clouds with scattered
light showers possible across the high peaks of the Greens and
Adirondacks, and the Northeast Kingdom...not expecting any real
measurable precipitation with this front. Behind this winds will
turn out the north/northwest as high Canadian high pressure moves
overhead. Clouds clear briefly towards 00z before high clouds
increase once again as decaying convection from the midwest advects
eastward. High temperatures on Monday will be slightly below normal
for the northern areas in the mid to upper 60s and near normal
around 70 for much of the Champlain Valley and central/eastern VT.
Lows Monday night will be below normal in the low to mid 40s.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 336 PM EDT Saturday...Still some uncertainty in the
northeastern extent of a shortwave passing close to the area on
Tuesday. NAM/GFS/Canadian solutions graze Rutland and Windsor
counties (and points south) but keep much of the area mainly dry,
while ECMWF has widespread precipitation (with highest amounts
across southern areas) across the North Country...Euro outlier at
this point so have trended towards a more dry forecast, however have
included mention for chances for precipitation with greatest
likelihood Tuesday PM.

The active pattern continues for much of the remainder of the
extended as subtropical ridge across southeast US continues to pivot
systems over the North Country. Currently looking like widely
scattered showers Wednesday and Thursday with the potential for
embedded thunderstorms. PWATs increase once again with both of these
systems to around 1.5" with good fetch of Gulf moisture. Still a
little far out but we will continue to monitor for any
convective/hydro threats.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...Showers and thunderstorms are currently
tracking across northern New York and will continue to push
eastward through the evening and overnight hours. Have mention
of TS at KBTV, KSLK and KMSS based on latest data but lightning
should become more isolated as the atmosphere stabilizes.
Localized IFR visibilities are to be expected in the
thunderstorms. Ceilings will trend from VFR to MVFR over the
next few hours as the warm front moves through. Saranac will
likely see a period of IFR ceilings tonight under a strong
inversion but should be on the only place. Precipitation quickly
tapers off from west to east after 06Z with clearing skies
expected on Sunday. A wind shift from south to northwest is
expected after 16Z Sunday.

Outlook...

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

&&

.MARINE...
As of 323 PM EDT Saturday...A Lake Wind Advisory is in effect
tonight as south winds increase into the 15 to 25 kt range. This
will create a light to modest chop on open waters and in bays
with southerly exposures. Steadier rainfall this evening will
also reduce visibility to below 5 miles at times, especially
late this afternoon and this evening. Small craft should
exercise caution

&&

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

&&

$$
SYNOPSIS...JMG
NEAR TERM...Clay/JMG
SHORT TERM...LaRocca
LONG TERM...LaRocca
AVIATION...Clay
MARINE...JMG