617
FXUS61 KBTV 040025
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
825 PM EDT Sat May 3 2025
.SYNOPSIS...
Intervals of showers and below normal temperatures will prevail on
Sunday with greatest potential of some dry weather near the
International Border. Temperatures will only warm into the upper 40s
to mid 50s, except mid 60s over the northern Saint Lawrence
Valley on Sunday. The unsettled and cool weather pattern
continues until early this upcoming week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 718 PM EDT Saturday...There will be an interruption in
precipitation this evening before widespread rain begins again
after midnight. Should skies break, fog will form with potential
for some localized areas of dense fog. The forecast remains on
track.
Previous Discussion...GOES-19 water vapor shows a deepening and
closing off mid/upper lvl cyclonic circulation over the central
MS River Valley with deep moist conveyor belt from the SE conus
into the Ohio Valley/NE conus. This deep moisture conts to
advect along a nearly stationary boundary from western PA into
southern/central New England and wl cont to be the focus for
additional showers tonight into Sunday. If you enjoyed the cool
and damp conditions of Saturday, guess what you are in luck
again for Sunday. As the flow remains strongly blocked tonight
into Sunday, expect plenty of clouds with additional showers and
some trrn enhanced qpf on the eastern side of the CPV/western
Slopes. Froude #`s <0.25 thru 00z Monday.
For tonight, we should see a brief break in the areal coverage of
showers this evening, per radar trends showing a narrow axis of
little rain over central NY/PA attm. Given small dwpt depressions,
light bl winds, and recent rainfall, areas of patchy fog are
possible in protected valleys and acrs the higher trrn tonight.
Meanwhile, additional deep layer moisture and elongated vorticity in
the fast confluent mid lvl flow wl race from southwest to northeast
with additional showers likely late tonight into Sunday. Both
GFS/NAM and ECMWF indicating a sharpening north to south pw and 850
to 500mb moisture gradient developing, which results in a
challenging pop/qpf fcst for Sunday, as sfc boundary remains south
of our cwa. The best mid lvl deformation and axis of moisture looks
to be from the High Peaks into central/southern VT, while near the
International Border could stay mostly dry on Sunday. Very difficult
to pin point the exact northern extent of precip, especially with
sfc high pres trying to advect drier dwpts southward. HREF 24hr
probability of qpf >0.25" is 60 to 80% along and south of a Tupper
Lake to Newport line on Sunday, with <5% over the SLV. THe
probability of qpf exceeding 0.50" in a 24 hour period on Sunday is
only 30 to 40% at most acrs central VT mtns on Sunday, which
indicates most of the rain wl be light again on Sunday. Have
utilized some high res NAM 3KM and 12z HRRR 2M temps to
highlight cooler temps within the rain axis on Sunday, while SLV
should warm into the mid 60s with drier conditions.
As 1028mb high pres tries to build southward toward our northern cwa
on Sunday night, the areal coverage of precip should become confined
to southern VT. Guidance conts to show a very sharp north to south
moisture gradient, making for a challenging fcst with regards to
placement of qpf/pops. A small 25 mile shift to the north, would
result in higher qpf/pops into central/northern cwa on Sunday night.
For now we have nil pops near the International Border to low likely
south of Route 4. Lows range from the mid 40s to lower 50s.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY/...
As of 330 PM EDT Saturday...An upper-level low will continue to spin
across Ohio as it slowly moves to the northeast closer to our
region. This system will stagnate due to an area of mid-level
deformation across Quebec and a blocking high off the coast of the
Canadian Maritimes. Decent moisture transport off the Atlantic on
Monday will keep precipitation chances around across southern
Vermont, but dry air associated with a col in northern New York will
help to limit shower activity in the northern regions of the area.
Although shower chances are lower to the north Monday, clouds from
upper-level subsidence will limit any sunshine. Shower chances will
continue Monday night across southern Vermont, increasing northward
by Tuesday morning, as the low gradually meanders to the northeast.
Shower activity looks to become more widespread Tuesday into Tuesday
afternoon with some instability developing across the St. Lawrence
Valley. Temperatures will be in the upper 50s to low 60s where
precipitation will fall in southern Vermont, but where drier air
exists to the north highs could reach into the upper 60s. Overnight
lows look to dip towards the low 50s for most Monday night.
&&
.LONG TERM /TUESDAY NIGHT THROUGH FRIDAY/...
As of 330 PM EDT Saturday...The pattern will remain stagnant through
the better portion of mid- week. The upper low will finally translate
over the area Tuesday night into Wednesday with the best chances for
precipitation Tuesday night in southern Vermont and Wednesday along
the international border. There is potential for some heavier
precipitation Tuesday night into Wednesday night with PWATs around 1
inch and aligned upper-level divergence with the moisture conveyor
belt. There are no extraordinary precipitation amounts over the 5
day period, but continued light precipitation could yield areas of
1-2" over the next 5 days. NBM probabilities of 72-hr amounts
greater than 1" are generally 20-40% with higher probabilities well
to our south. Any northward jogs of the low or convective elements
may skew towards the higher amounts, and we will continue to monitor
the conditions over the next few days.
As the upper low finally departs Wednesday night, a new upper low
will promptly replace it building in from the St. Lawrence Valley for
Thursday. Ensembles have trended the precipitation chances down with
a more progressive system. Shower chances look best in areas east of
the Greens on Thursday. If the trend holds, we may have a chance at
our first precipitation free Saturday. NBM probabilities still have
a 10-20% chance for precipitation, but that is definitely lower than
climo probabilities at 40%. Temperatures by late week look to be on
the cooler side with highs in the upper 50s behind the upper low,
however, a warming trend looks apparent by the weekend.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...With a break in rainfall, CIGs will improve
for most locations mainly to a mix of MVFR/VFR. The exception
will be at RUT where precipitation or low stratus will keep
conditions ranging mainly VLIFR to IFR. In this space of time
between rainfall, some fog may form elsewhere as well, but
extent and potential at terminal sites will be dependent on
cloud breaks. MVFR/IFR is expected to become more widespread
again 04-08Z as the next slug of moisture moves into the region.
MSS will be the odd one out staying on the periphery of lower
CIGs; one caveat could be some overnight fog should clouds break
more than expected. Otherwise, winds will not be much of a
concern to aviators with light winds becoming more northwesterly
on Sunday.
Outlook...
Sunday Night: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Monday: Mainly VFR, with local MVFR possible. Chance SHRA.
Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Tuesday: MVFR/IFR conditions possible. Definite SHRA, Slight
chance TSRA.
Tuesday Night: MVFR/IFR conditions possible. Chance SHRA.
Wednesday: Mainly MVFR, with areas VFR possible. Likely SHRA,
Slight chance TSRA.
Wednesday Night: Mainly MVFR, with local IFR possible. Chance
SHRA.
Thursday: Mainly VFR, with areas MVFR possible. Chance SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Boyd/Taber
SHORT TERM...Danzig
LONG TERM...Danzig
AVIATION...Boyd/Taber
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