492
FXUS61 KBTV 192330
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
730 PM EDT Wed Jun 19 2024

.SYNOPSIS...
Dangerous heat and humidity will continue across the region into
tomorrow for just one more day with highs in the 90s combining with
humid conditions to create heat index values up to 100. Please
continue to take appropriate precautions to avoid heat stress as
heat can have a compounding effect. Scattered to numerous showers
and thunderstorms are possible tomorrow, which could possibly severe
and heavy featuring hail, frequent lightning, downpours, and gusty
winds.

&&

.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 405 PM EDT Wednesday...Showers and thunderstorms that are
stretched across the forecast area this afternoon will gradually
taper off into the evening as we lose instability and sunlight
tonight. Temperatures are not expected to fall very low tonight with
forecast lows in the lower to mid 70s for most. If temperatures at
the Burlington Airport (BTV) don`t fall below 80 degrees by
midnight, we will tie the all time warmest minimum temperature. Some
areas of the forecast area, particularly valley spots that had rain
today, may experience patchy fog tonight as moisture gets trapped
under an inversion.

The mild night will start us off warm again tomorrow as temperatures
climb into the upper 80s to mid 90s. Hottest conditions are most
likely to occur in the Champlain and Connecticut River Valley, where
heat indices could approach 100. This will be not quite as warm as
today was, as a frontal boundary is likely to produce some
precipitation and bring slight cooling from north to south. With
shortwave forcing, increasing wind shear, sufficient instability,
and oppressive heat, there is a marginal to slight (5-15%) chance of
a severe thunderstorm for most places across the forecast area of
northern New York and Vermont. The primary severe threat from any
storms will be gusty, damaging winds, however, there is also the
potential for hail and frequent lightning. In addition to severe
concerns, very high precipitable water rates are conducive to heavy
downpours. If storms become stationary along the frontal boundary
and repeat downpour in one spot, there could be the risk of flash
flooding.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 405 PM EDT Wednesday...The short term focus wl be potential for
showers and embedded thunderstorms associated with slow moving cold
frnt dropping south. The greatest potential for showers and embedded
storms look to be acrs central/southern VT on Friday where pw values
are still near 1.5" and sfc based CAPE values are in the 500-1000
J/kg range. Much drier air with lower humidity values wl be near the
International border associated with sfc high pres near Hudson Bay.
The latest trends however have been for less of a southerly push
associated with this 1022mb high pres, as frnt becomes stationary
acrs central NY into SNE. Progged 925mb temps btwn 18-21C support
cooler highs on Friday with values upper 70s to mid 80s. Greater
potential for cloud cover may hamper warming acrs southern sections,
but humidity values wl be higher in Rutland/Windsor counties too.
Areal coverage of showers wl decrease on Friday night as weak
subsidence develops and axis of deepest moisture is just south of
our cwa. Have continued with some token 15-25% chance pops for now
with temps in the 60s. Also, given recent rainfall and some lighter
winds areas of patchy valley fog is possible, especially CT River
Valley and parts of central/northern VT.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 405 PM EDT Wednesday...An unsettled pattern with occasional
showers are likley for this upcoming weekend into early next week.
The exact timing and placement of heaviest precip is still getting
fine tuned, but several parameters are coming together for localized
heavy rainfall. These parameters include a nearly stationary west to
east oriented boundary, pw values btwn 1.5 and 2.0", deep warm cloud
layer up to 11kft, and intervals of favorable 850-700mb fgen
forcing. Its always challenging for placement of heaviest qpf in
narrow west to east axis of favorable dynamics and moisture that is
several days away. Best potential attm looks to be acrs the northern
Dacks into central/northern VT. WPC has part of our cwa in marginal
for Day 3, which looks reasonable, especially given the activity
over the next 1 to 2 days. For now have continued with high likely
pops for Saturday into Sunday. As we get closer these pops can be
fine tuned with regards to timing and placement and hopefully we can
find a few hours of dry weather this upcoming weekend. Temps wl be
near normal for highs with values in the mid 70s to lower 80s while
lows hold in the 60s. Late Sunday into Monday, potent s/w energy and
associated sfc low pres wl track north of our cwa. However, given
the dynamics and boundary associated with this system, another
period of showers with embedded storms looks likely. Still some
uncertainty on timing and amount of instability, but dynamics should
be enough to support some rumbles of thunder. Much drier and quieter
weather returns for early to middle of next week with near normal
temps.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...Aviation challenge is fog potential tonight
followed by timing of convection on Thursday. Sfc dwpts are in
the upper 60s to lower 70s, indicating very high low level
moisture content, but KCXX VAD shows 20 knots at first gate.
So thinking some 3-5SM HZ is possible at SLK/PBG/MPV and EFK,
but given winds just off the deck, feel potential for fog with
IFR or lower conditions is <10% attm. For Thursday, expect areal
coverage of showers/storms to increase toward noontime with some
localized strong to severe storms possible. Any storms will have
the potential to produce strong/gusty outflow winds up to 40
mph, frequent cloud to ground lightning and MVFR vis in heavier
rain. The greatest potential will be between 17z and 22z on
Thursday, with conditions improving toward sunset. Have used
VCSH showers for now, but as confidence in timing improves
prevailing groups and tempo`s for MVFR cigs/vis will be needed
on Thurs.

Outlook...

Thursday Night: VFR. Chance SHRA, Slight chance TSRA, Patchy BR.
Friday: VFR. Chance SHRA.
Friday Night: Mainly VFR, with local MVFR possible. Slight chance
SHRA.
Saturday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Saturday Night: Mainly MVFR, with areas VFR possible. Likely
SHRA.
Sunday: Mainly IFR, with local MVFR possible. Likely SHRA, Chance
TSRA.
Sunday Night: Mainly VFR, with local IFR possible. Likely SHRA.
Monday: MVFR. Likely SHRA.

&&

.CLIMATE...
Hot temperatures will result in values near records. Below are
some of the records under threat of being broken.

Record High Temperatures:

June 20:
KBTV: 95/2012 Forecast 92
KMPV: 90/2020 Forecast 90
KPBG: 94/1964 Forecast 88
KMSS: 92/2012 Forecast 87
KSLK: 92/1995 Forecast 86


Record High Minimum Temperatures:

June 20:
KPBG: 70/1953 Forecast 73
KSLK: 68/2012 Forecast 67

&&

.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Heat Advisory until 8 PM EDT Thursday for VTZ001>011-016>021.
NY...Heat Advisory until 8 PM EDT Thursday for NYZ026>031-034-035-
     087.

&&

$$
SYNOPSIS...Storm
NEAR TERM...Storm
SHORT TERM...Taber
LONG TERM...Taber
AVIATION...Taber
CLIMATE...Team BTV