Area Forecast Discussion
Issued by NWS Burlington, VT

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS61 KBTV 240048
AFDBTV

Area Forecast Discussion
National Weather Service Burlington VT
848 PM EDT Sat Jul 23 2016

.SYNOPSIS...
More scattered showers and thunderstorms are expected across the
North Country through this evening. Clearing and patchy fog
overnight. Sunday looks mostly sunny and seasonable under hand
yet another possibility of showers and thunderstorms late Monday.
Warm and mostly dry summer weather looks like it will continue Tue
and Wed.

&&

.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of 848 PM EDT Saturday...After a very active day which saw
numerous reports of severe weather things have quieted down.
Impressive development of a severe quasi-linear convective complex
and associated cold pool earlier this afternoon which raced
southeast at 40 knots affecting much of the Champlain Valley and
southern/south central Vermont as well as portions of Essex County
in New York with widespread wind damage and numerous water
rescues. This activity has weakened and exited our far southern
counties a few hours ago. An isolated shower or stray storm may
still be possible along the international border counties through
10 pm or so as weak additional shortwave energy rotates southward
but additional strong/severe weather is expected. Lows tonight
appear on track in the 50s to around 60 with patchy fog in favored
locales, though honestly a little br/fog could be possible just
about anywhere later tonight given recent rains and light winds in
the nocturnal boundary layer after midnight. Prior discussion for
Sunday/Sunday night follows. Have a great evening.

.Sunday...High pressure at all levels will allow plenty of sun with
850mb temps 15-16C and 925mb of 18-19c suggest mid 80s and much of
guidance has low 80s...thus nudged up deg/two.

.Sunday night...Upper Ridge dampens and passes FA with some embedded
energy, return flow aloft and deep moisture thus chance of showers
and possible elevated convection toward Monday morning which will
complicate matters for Monday.under "Marginal Risk" of severe
thunderstorms and we are in good agreement.

&&

.SHORT TERM /MONDAY THROUGH MONDAY NIGHT/...
As of 344 PM EDT Saturday...Rather busy with current severe
weather...thus bnorrowing from previouss shift with some edits
here and there. The end result...looks more uncertain than the
last few days here.

For days, guidance has been indicating unsettled conditions (eg:
showers and t-storms) to be possible. Still, things are not totally
clear. What I do expect is that a fairly robust shortwave will be
approaching the region late in the day. This will sync up daytime
heating with the best dynamics aloft. Models do indicate surface
based instability of probably 1000-1500 J/kg (NAM as typical is
higher) due to a warmer and more humid airmass getting into place.
Just how much instability we achieve will be related to how much sun
we see. 925mb temperatures are expected to become very warm -perhaps
23 to 25C. Under perfect atmospheric mixing conditions, this would
result in temperatures at the valley floor pushing into the mid 90s!
However, it appears we`ll have a good amount of clouds to restrict
heating to a degree. Though we should still easily reach the mid
80s.  The 0-6km bulk shear values are in the marginal level for
getting storms to become on the strong side.  SPC does have the
region in a marginal risk, but they also have some concerns about
the mix of ingredients lining up perfectly to develop severe t-
storms. Evaluation of various forecast sounding for Monday have some
"goofiness" (thats a technical term, by the way) showing in the
profiles. Not sure if that is due to convection within the models,
or if it`s a sign that despite the very warm air aloft, we`ll have
some inversion in place to restrict mixing, which in turn means
restricted convection.  At this point, will play the middle ground,
and keep PoPs in the 40-55% range and see how future guidance
trends.

&&

.LONG TERM /TUESDAY THROUGH SATURDAY/...
As of 344 PM EDT Saturday...Decent agreement with the 00z and
12z suites of models, and much of the week should be relatively
quiet, but feature more or less typical summer weather. Most of
the week we`ll see temperatures running a bit above normal. Looks
sunny and warm for both Tuesday and Wednesday. GFS and ECMWF start
to advect in some moisture for Thursday, along with having a
little more troughiness develop and perhaps a weak front sliding
down from Quebec. Thus it appears we`ll see some showers and
t-storms around. At this point, they appear to be of the garden
variety as I don`t see strong dynamics in place. Kept with a model
blend and painted in 30-40% PoPs.

More uncertain on Friday and Saturday with general trofiness
dropping into somewhat humid airmass for threat of showers and
thunderstorms friday and saturday but confidence is lower than mid
weeks forecast.

&&

.AVIATION /01Z Sunday THROUGH Thursday/...
Through 18z Sunday...Mainly VFR but scattered brief MVFR/IFR in
stronger showers and thunderstorms moving n to s thru 23z. High
pressure starts to move in from the NW overnight with light winds
and patchy dense fog and LIFR forming again 06-12Z at KSLK and
KMPV.

Winds generally light west to northwest at 5 to 10 knots.

Outlook 18z Sunday through Tuesday...

Sun...Mainly VFR under weak high pressure.

Mon/Monday night...VFR with scattered brief MVFR/IFR in showers
and thunderstorms with frontal passage.

Tuesday...VFR/high pressure.

&&

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

&&

$$
SYNOPSIS...Sisson/SLW
NEAR TERM...JMG/SLW
SHORT TERM...Nash/SLW
LONG TERM...Nash/SLW
AVIATION...Sisson/SLW


USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.