334
FXUS61 KBTV 210522
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
122 AM EDT Sun Jun 21 2026
.WHAT HAS CHANGED...
As of 238 PM EDT Saturday...
The forecast for the weekend remains on track with continued
showers and a few embedded rumbles of thunder expected. Given
recent rainfall, we continue to monitor rainfall amounts and
hydrological conditions closely, but outside of some possible
localized ponding, widespread flooding is not anticipated at
this time.
&&
.KEY MESSAGES...
As of 238 PM EDT Saturday...
1. Rounds of showers will continue through Sunday. Widespread
flooding is not expected, though some isolated flooding and
ponding in poor drainage areas is possible.
2. A steadier soaking rain is expected to move from west to
east through New England Monday into Monday night, mainly impacting
our southern counties but with the potential to track further north.
3. After some mid week drier conditions, unsettled weather is
favored to return by late week.
&&
.DISCUSSION...
As of 238 PM EDT Saturday...
KEY MESSAGE 1: The showery and unstable weather regime will continue as
an upper low slowly pivots eastward over the Canadian
Maritimes. Shortwaves rounding the base of this trough today
along with additional shortwave energy rippling into the area
from the west will support multiple rounds of showers with some
embedded thunderstorms lasting through the end of the weekend.
Despite continued cloud cover, we`ll see the development of
500-1000 J/kg SB CAPE this afternoon and again Sunday afternoon.
Mid-level lapse rates generally will remain in the 5-6.5
degC/km range, which all together could support the development
of some scattered convective showers and potentially some
embedded pulse-type thunderstorms this afternoon and again
Sunday afternoon. Lack of deep-layer shear will keep
thunderstorms generally sub-severe, and the Storm Prediction
Center accordingly only has our area outlined in the General
Thunder outline for today and tomorrow.
While this means severe winds and hail are generally not expected,
the primary concern remains briefly moderate to heavy rain within
heavier showers or thunderstorms, capable of producing localized
ponding or isolated flooding. This is especially true in areas that
have seen moderate or heavy rainfall over the last 24 hours, and
thus already have near saturated soils. In general, the highest
precipitation amounts over the last 24-48 hours have been observed
near the International Border and over the Champlain Valley and
northern Green Mountains. The good news is that precipitation rates
this afternoon and tomorrow are not expected to be too concerning,
with precipitable water values of around an inch limiting the heavy
rain threat. The one concern would be any areas where heavier
showers or thunderstorms train over one area, in which case those
areas will need to be watched closely. The northwest to southeast
flow continues to support a non-zero potential for some training,
but so far today showers have been moving fast enough to limit the
concern.
Between today and tomorrow`s showers and thunderstorms, we expect a
general additional quarter to half inch of rain, with locally higher
amounts likely in areas that experience training showers or storms.
Six hour Flash Flood Guidance from the Northeast River Forecast
Center is around 1.8 to 2.25 inches. Thus, additional rainfall rates
for today and tomorrow are forecast to remain below these
thresholds, and widespread flooding is not anticipated. We will also
continue to watch area rivers closely as rivers are generally
running high but are within banks. At this point, no rivers are
forecast to go into flood stage over the next few days, but this
could change if precipitation amounts locally exceed our current
forecast.
KEY MESSAGE 2: The pattern remains active going right into the upcoming
work week. The upper-level low over the Canadian Maritimes departs
to the east, but will quickly be replaced by a surface low-pressure
system/open upper level wave moving east/northeastward out of the
Ohio River Valley. This system will bring a eastward moving wave of
steady soaking rain through New England Monday, though models still
diverge on the exact track of the low and the placement of the
associated rain. Notably, models have shifted the track further
northward and closer to/through our forecast area with today`s
latest runs. This results in a tricky forecast, as it initially
looked like at least northern portions of our forecast area would
stay north of the system and avoid the soaking rain. However,
if the trend continues, portions of our area could see an
additional inch or more of rainfall. The most likely scenario at
this point (which is reflected in our current forecast) is that
the heavier rainfall is limited to our southern counties.
However, we have tweaked PoPs up slightly for much of the area
for Monday, and will continue to adjust if the northward trend
continues. Temperatures will remain near seasonal norms for
Monday and Tuesday.
KEY MESSAGE 3: Broad longwave troughing is projected to lift a little
with a flat, migratory ridge quickly moving through its base on
Wednesday. This favors drier conditions for the middle of next week,
but could still see some terrain showers as temperatures warm back
to the upper 70s to around 80 degrees. Projections suggest dry
conditions will be short-lived as a consolidated 850-500mb trough
moves through the Great Lakes region likely tilting local winds out
of the southwest and increasing diffluence aloft by Thursday. This
would keep the warmer temperatures through Thursday, but
diffluence/height falls aloft point to increasing shower potential.
Models are split on timing, but low pressure could move through the
region Thursday/Friday into Saturday with more widespread
rain/thunderstorms possible. Depending on details of timing and how
wrapped up the low gets, it`s possible that we could see an active
period of thunderstorms towards the end of next week.
&&
.AVIATION /06Z SUNDAY THROUGH THURSDAY/...
Through 06Z Monday...Scattered showers persist across our region
this morning with a mix of MVFR and VFR conditions at our taf
sites. Thinking the MVFR cigs at SLK will become IFR in the next
1 to 2 hours and prevail thru 14z, before improving. Elsewhere,
thinking mostly MVFR cigs prevail at EFK with VFR at PBG/BTV/MPV
and RUT with brief MVFR cigs possible in any shower activity.
Also, did note on the FAA webcam at RUT some very shallow ground
fog on the southwest perspective, so have placed BCFG few002 to
cover this potential. Given southeast winds 3 to 5 knots,
thinking fog coverage at RUT should be limited. Additional
scattered shower activity is expected on Sunday, which will be
covered with PROB30 groups in the next 12z taf package. Light
and trrn driven winds under 6 knots this morning, become
northwest at 4 to 8 knots today.
Outlook...
Monday: VFR. Chance SHRA.
Monday Night: Mainly VFR, with local IFR possible. Chance SHRA.
Tuesday: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Tuesday Night: VFR. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. Chance SHRA, Slight chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
WHAT HAS CHANGED...Duell
DISCUSSION...Boyd/Duell
AVIATION...Taber
|
