FXUS61 KBTV 262317
Area Forecast Discussion
National Weather Service Burlington VT
717 PM EDT Mon Jun 26 2017
Scattered showers and isolated thunderstorms will wane across
the area this evening, though reblossom in earnest on Tuesday as
vigorous upper energy pushes into the area. After a mainly dry
Wednesday, unsettled weather returns for later in the week and
into next weekend. The potential for some heavier rainfall will
exist, especially by next weekend as a front lingers in the area
and conditions trend warmer and more humid.
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 715 PM EDT Monday...Have updated forecast to reflect
current radar trends. No significant changes from previous
forecasters thinking. Previous discussion follows.
Scattered showers and a few/isolated storms have developed as
expected this afternoon along a weak surface trough draped from
near Lake Ontario east into central New England as of mid-
afternoon. Weak convergent flow and low- end surface-based
instability along this boundary is driving this activity in the
absence of larger synoptic- scale forcing, and given rather poor
lapse rates aloft coverage should wane as we progress beyond
sunset and toward the overnight hours. A brief heavy downpour
will be possible here and there, but many areas will remain dry
so don`t cancel any outdoor plans you may have for this evening.
Lows a blend of consensus guidance offering lows ranging
through the 50s in most spots.
A better coverage of showers and thunderstorms is expected on
Tuesday as another fairly vigorous shortwave swings directly through
the region. Juxtaposition of this feature with chilly thermal
profiles aloft (-20 to -22C at 500 mb) suggests convection will
likely organize into one or two bands which will sweep across the
area during the late morning and afternoon hours. Not enough
instability to drive anything to severe levels, but given low wet
bulb zero heights below 8 kft some brief gusty winds and small hail
could certainly occur. Best probabilities across eastern counties
where at least some morning/early afternoon partial sunshine will
steepen low level lapse rates. Highs a bit cooler tomorrow with the
convection and an broad increase in afternoon ambient cloud
cover...mainly 60s to perhaps a few spot 70F readings south and east.
Shortwave then exits east through the evening hours on Tuesday with
convective coverage lessening over time and leaving a mainly dry
overnight period. Again, a few early evening storms may spit
out some small hail east early. Low temperatures perhaps a
degree or two cooler than tonight, generally upper 40s to mid
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 247 PM EDT Monday...Wednesday looks to be a relative
minimum in the convective activity for the week. Northwest flow
aloft in the wake of the shortwave should dry things out despite
a fair amount of cold air aloft. There will be some instability
developing in the afternoon but areal coverage should remain
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 247 PM EDT Monday...Thursday will begin a stretch of
active weather through the end of the week. A wave along a
frontal boundary will travel north of the border Thursday
through thursday night with a boundary stretched out east to
west. Showers and thunderstorms will develop to the west of the
area in the lower great lakes and southern Ontario and move east
along the boundary. Instability progged to be meager Thursday
and thursday night so overall thunder chances area fairly low.
Instability increases Friday so increased thunder chances Friday
and Friday night.
Southwesterly flow will continue to transport more moisture rich
air into the region Friday and Saturday. Available instability
progged to increase with the moisture plume moving into the
area, but deep layer shear is meager at this point. PWAT values
by Saturday way back up into the 1.50-2.00" range and heavy
rainfall is definitely a concern. The rainfall of the last week,
combined with whatever falls Thursday could set the stage for a
flash flood event Saturday. Amount and location of Thursday`s
rainfall will set the antecedent conditions for any potential
flooding Saturday. Still quite far out in the forecast, but
definitely bears watching.
.AVIATION /23Z MONDAY THROUGH SATURDAY/...
Through 18Z Tuesday...Mainly VFR with SCT/BKN cigs in the
040-080 AGL range through 12Z Tuesday under light south to
southwesterly flow. Scattered showers/isolated thunderstorms to
affect terminals in the 18-04Z time frame this
afternoon/evening, but most of the period should remain dry.
KBTV threat the highest in the 22-01Z time frame. Overnight any
lingering showers to end leaving mainly VFR. Some brief and
patchy MVFR cigs in the 015 AGL range possible at KMPV and KSLK
from 09-12Z but confidence low. After 12Z Tuesday more robust
energy pushing into the area aloft will spark better coverage of
showers/sct storms. Highest coverage initially at KSLK/KMSS from
14Z onward where MVFR will be offered. Further east
shower/storm probabilities increasing by 18Z but covered with
just VCSH at this point given timing uncertainty.
Tuesday: VFR. Chance SHRA...Slight Chance TSRA.
Tuesday Night: VFR. Chance SHRA...Slight Chance TSRA.
Wednesday: VFR. Breezy. Chance SHRA...Slight Chance TSRA.
Wednesday Night: VFR. Slight Chance SHRA...Slight Chance TSRA.
Thursday: VFR/MVFR. Chance RA...Chance TSRA.
Thursday Night: VFR/MVFR. Likely RA...Likely SHRA... Chance TSRA.
Friday: VFR. Chance SHRA...Chance TSRA.