-- Discussion containing changed information from previous version are highlighted. --
196
FXUS61 KBTV 261716
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
116 PM EDT Thu Jun 26 2025

.SYNOPSIS...
Much cooler temperatures with plenty of clouds will impact our
region today, along with a few light rain showers. Any rainfall
amounts will be light and generally under a tenth of an inch. An
active period of weather is anticipated late Friday into Saturday
with several rounds of localized heavy rainfall expected, along with
some localized flash flooding possible. Drier and warmer weather
returns by early next week.

&&

.NEAR TERM /THROUGH FRIDAY/...
As of 1014 AM EDT Thursday...Just a few minor adjustments needed
to the forecast this morning. Increased cloud cover continues to
stream into the region, and despite the radar returns
precipitation is not quite making it to the surface. As the
afternoon progresses, some light precipitation can be expected,
but the current forecast has this covered.

Previous discussion below:
GOES-19 water vapor shows fast confluent flow aloft acrs our
cwa which is in btwn a strong mid/upper lvl ridge over the se
conus and departing trof over eastern Canada. A pocket of
enhanced mid lvl moisture associated with decaying MCS wl dive
southeast acrs our cwa today. However, the combination of
warming cloud tops on the GOES-19 IR satl imagery, decreasing
reflectivity structure on radar and drier air at the llvls
undercutting deeper moisture aloft wl result in light qpf today.
Have kept the general idea of chc pops with qpf <0.10". North
winds, plenty of clouds, and scattered light precip wl keep
temps in the mid/upper 60s to mid 70s acrs our fa. Tonight
latest 00z HRRR indicates slightly stronger progged composite
reflectivity acrs parts of our cwa, so have bumped pops into the
40- 60% range, especially early this evening. Once again,
precip might have difficulties reaching the ground, as drier air
near the sfc is advecting into our region on north/northeast
winds around sfc high pres over northern Maine. Comfortable lows
in the upper 40s to near 60F anticipated. Friday looks
unsettled again as a warm frnt tries to lift northward, but runs
into dry air. Guidance is struggling on the areal coverage and
placement of potential precip attm, so have chc east to low
likely west in the morning, increasing to 60 to 80% in the aftn
from west to east. The highest probability of precip looks to be
over northern NY, but some guidance has greatest potential
north of our cwa on Friday. If this trend prevails, lowering of
pops maybe needed acrs portions of our cwa. Any qpf on Friday wl
be in the 0.10 to 0.25" range with some localized higher
amounts possible in any convective elements. Highs in the mid
60s to lower 70s.

&&

.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/...
As of 316 AM EDT Thursday...An active period of wx anticipated with
several rounds of localized heavy rainfall likely, along with
isolated flash flooding possible. Still considerable spread in exact
placement of heaviest qpf axis and associated precip amounts, but
synoptic scale setup remains unchanged with latest 00z guidance. If
current trends continue a flood watch maybe needed for portions of
our area late Friday into Saturday for rainfall amounts in the 1.5
to 2.5" with localized amounts near 4.0" possible.

The large scale pattern indicates deep mid/upper lvl ridge acrs the
se conus with developing south/southwest flow in the 850mb to 300mb
layer, which helps to advect pw values in the 1.50" to 1.80" range
into our cwa. 00z GFS shows pw values approaching 2.0" by 06z Sat
acrs our fa, which is 150% to 200% of normal for late June. In
addition to very deep moisture profiles, an un-seasonably strong
250mb jet of 140 to 160 knots wl be lifting acrs southern Canada,
placing our northern cwa in the favorable right rear quadrant for
promoting large scale ascent and strong ulvl divergence. Meanwhile,
in the 925mb to 700mb layer a sharpening llvl gradient wl be present
acrs our region, helping to enhance bands of favorable 850 to 700mb
fgen forcing and promoting localized heavy rainfall rates. This
narrow axis of favorable fgen forcing is extremely difficult to
predict and correlates very closely with axis of max qpf. If the
strengthening 850mb jet pushes warmer air further northward and
better/deeper instability develops overhead, the axis of heaviest
rainfall would be located over southern Canada, which is supported
by several pieces of guidance. However, if the sharp boundary and
associated instability is acrs our fa, along with the nose of the
850mb jet, the heaviest precip would be centered acrs our
central/northern cwa. The placement of this 850mb jet is key for
enhanced llvl moisture convergence and development of elevated
instability, especially on Saturday, when better dynamics aloft
arrive. Its the elevated instability parameters in combination of
warm cloud depths over 12,000 feet, which could enhance rainfall
rates and cause localized flash flooding. The MCS and associated
convection crntly over central NE is progged to angle our way and
ride along a nearly stationary boundary draped somewhere acrs the ne
conus late Friday into Sat. Based on EPS and GEFS and averaging the
latest deterministic guidance, the greatest potential for the
heaviest rainfall would be near the International Border over
northern NY into central/northern VT. WPC continues a slight risk (2
out of 4) acrs this region, which looks reasonable. Highs on
Saturday wl be in the mid 60s east to mid 70s west with increasing
sfc dwpts/humidity values.

&&

.LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/...
As of 316 AM EDT Thursday...Rainfall appears likely to linger across
Vermont Saturday evening but global deterministic guidance remains
split on how fast the precipitation exits. Some of the guidance
depicts the frontal boundary getting hung up across the Green
Mountains with light rain continuing into Sunday morning while
others have a more progressive frontal boundary allowing rainfall to
end sooner. The ensembles seem to be a split of the two showing rain
ending during the pre-dawn hours on Sunday but any additional
rainfall during this timeframe is likely to be light as the highest
PWAT air mass slides off to the east. Still, runoff from higher
terrain will continue during this time frame and could allow for
some additional flood concerns depending on where exactly the
heaviest rain axis sets up on Friday and Saturday.

Brief ridging on Monday will allow for some peaks of sunshine and a
brief period of dry weather in the wake of a warm front.
Temperatures on Monday will warm back above seasonal normals with
highs in the 80s to near 90 degrees in the wider valleys. Subsidence
from mid-level ridging should help prevent any pop-up afternoon
thunderstorms on Monday. As we head into Tuesday, the weather once
again looks to be rather unsettled. A cold front is slated to move
across the region during the day on Tuesday but with plenty of
timing discrepancies between deterministic and ensemble guidance. As
usual, it does appear that the approaching cold front on Tuesday
will come through piece by piece with a pre-frontal trough Tuesday
morning, followed by the upper level supper, then the surface cold
front, and ultimately the low level wind shift. Given these features
are out of phase, we could see some strong storms but the
possibility for severe storms on Tuesday seems pretty low. There is
plenty of time for this to change so we will be watching this
closely over the next several days. Following the cold front, a
longwave trough appears likely to situate across the region which
will bring seasonal temperatures with the chances for daily showers
and maybe a rumble of thunder or two.

&&

.AVIATION /17Z THURSDAY THROUGH TUESDAY/...
-- Changed Discussion --
Through 18Z Friday...Overall, VFR conditions and light winds
are expected through the TAF period. Some light rain showers
are generally expected between 18Z and 00Z across our terminals
but given that the rain is expected to fall out of a 10kft
deck, much of it will likely evaporate prior to making it to the
ground. Any rain that does make it down to the ground will be
light and likely won`t have any impact on the flight category
expect some brief periods of MVR Vis. MPV could see some early
morning fog if the mid level deck clears out, with some pre-dawn
IFR conditions. Winds will out of the northeast this afternoon
at 5-10 knots, becoming light and variable overnight before
becoming southeasterly at 5-10 knots tomorrow.

Outlook...

Friday Night: Mainly VFR, with local MVFR possible. Definite
SHRA, Slight chance TSRA.
Saturday: Mainly MVFR, with local IFR possible. Definite SHRA,
Slight chance TSRA.
Saturday Night: Mainly MVFR, with local IFR possible. Chance
SHRA, Slight chance TSRA.
Sunday: Mainly MVFR, with local IFR possible. Slight chance SHRA.
Sunday Night: Mainly VFR, with local IFR possible. NO SIG WX.
Monday: Mainly VFR, with areas MVFR possible. Slight chance SHRA,
Slight chance TSRA.
Monday Night: Mainly VFR, with local MVFR possible. Likely SHRA,
Slight chance TSRA.
Tuesday: MVFR/IFR conditions possible. Likely SHRA, Slight chance
TSRA.
-- End Changed Discussion --

&&

.HYDROLOGY...
The latest NWS forecast continues to support the idea of several
rounds of moderate to locally heavy rainfall will be possible
late Friday into Saturday. With boundary position and movement
at play, the exact placement of heaviest rainfall remains
somewhat uncertain, though there is fairly decent consensus that
the focus will lie across far northern NY into the northern
third of Vermont. Given near normal streamflows and 0-40cm soil
moisture profiles, we do have some wiggle room/capacity to
handle some of the runoff. As such, widespread mainstem river
flooding is not expected at this point with the emphasis more on
the flash flood threat in small streams/watersheds in steep
terrain. However, a few of the smaller rivers may see sharp
rises by Saturday. Our current precipitation forecast indicates
1.5 to 2.5 inches, with localized higher amounts likely across
the higher terrain in the aforementioned areas. It needs to be
stated, a significant variability in rainfall distribution
often occurs during convective events, so exact precip amounts
and placement are very challenging. Current 3/6 hour flash
flood guidance of between 2 and 3.5 inches all appears
reasonable at this time.

&&

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

&&

$$
SYNOPSIS...Taber
NEAR TERM...Kremer/Taber
SHORT TERM...Taber
LONG TERM...Clay
AVIATION...Verasamy
HYDROLOGY...NWS BTV