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klw

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    Thursday, July 13 - Friday, July 14, 2023 Convection

    in New England

    Posted 

    Severe Weather Statement
National Weather Service Burlington VT
639 PM EDT Thu Jul 13 2023

NYC031-VTC001-021-132245-
/O.CON.KBTV.TO.W.0001.000000T0000Z-230713T2245Z/
Essex NY-Addison VT-Rutland VT-
639 PM EDT Thu Jul 13 2023

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 645 PM EDT FOR
SOUTHEASTERN ESSEX...SOUTHWESTERN ADDISON AND NORTHWESTERN RUTLAND
COUNTIES...

At 639 PM EDT, a severe thunderstorm capable of producing a tornado
was located over Lake Dunmore, moving northeast at 30 mph.

HAZARD...Tornado and two inch hail.

SOURCE...Radar indicated rotation.

IMPACT...Flying debris will be dangerous to those caught without
         shelter. Mobile homes will be damaged or destroyed. Damage
         to roofs, windows, and vehicles will occur.  Tree damage is
         likely.

This tornadic thunderstorm will remain over mainly rural areas of
southeastern Essex, southwestern Addison and northwestern Rutland
Counties, including the following locations... Benson Bay, Catfish
Bay In Addison County, Huntley Island, Forest Dale, Beadles Cove,
Larrabees Point, Beartrap Island, Kerby Point, Hollands Pasture
Island, and East Shoreham.

    Thursday, July 13 - Friday, July 14, 2023 Convection

    in New England

    Posted

    BTV discussion (will Wiz make his wife read it to him- not for lack of ability to comprehend):

    https://forecast.weather.gov/product.php?site=BTV&issuedby=BTV&product=AFD&format=CI&version=1&glossary=1 

    NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 332 PM EDT Thursday...Active severe weather is ongoing
through this evening as an unseasonably strong low pressure
system drags a cold front eastward through our region tonight.
As expected, ingredients are present for rotating thunderstorms
in this region, near the triple point of a dynamic low pressure
system passing northeastward through the St. Lawrence Valley.
Our thermodynamic environment is impressive with mixed layer
CAPE at 2 PM of 1500-2000 J/kg, steep low level lapse rates and
moderate mid-level lapse rates helping updrafts strengthen.
Southwesterly wind shear is ample to keep storm structures
organized, with effective shear of 30 to 35 knots, and rotation
is substantial with 0-1 km helicity of 100 to 150 m2/s2.
Additionally, strong synoptic southerly winds will gradually
expand eastward, which are being channeled up the Champlain
Valley with wind gusts locally near 35 MPH. An occasional
stronger gust may cause isolated damage outside of the
thunderstorms, especially where we`ve seen very wet conditions.

A mixture of storm modes are present, which include linear
segments and discrete cells, which could include supercells. The
main hazards are damaging winds and flash flooding. Wind damage
has already been reported in the northern New York this
afternoon. Rotating storms have resulted in a reported funnel
cloud, but relatively high cloud bases (3000 feet or higher) may
limit the tornado potential. As thunderstorms expand northward
and eastward off of the Adirondacks, we will be concerned with
rotating storms and enhanced gusts in the Champlain Valley due
to enhanced low level convergence.

As the evening progresses, any discrete storms should tend to
be absorbed into a single fast moving squall line. Brief spinups
are possible along this line, and its fast forward speed will
tend to keep its severity going all the way eastward through
Vermont even as daytime heating. Scattered wind damage is
expected with the squall line. Less wind will be needed to
produce downed trees than typical given saturated soils in most
areas currently in a flood watch. Where a combination of
discrete and linear storms move over the same area, flash
flooding due to multiple rounds of heavy rain remains possible.
A heightened concern for flooding remains in our hard hit areas
of central Vermont, where capacity for additional heavy rain is
low. Improving conditions will arrive overnight with winds
becoming light and drier air settling in behind the cold front.
    • Like 3
    • Haha 1

    July 9th - 11th significant flood event

    in New England

    Posted 

    https://forecast.weather.gov/product.php?site=BTV&issuedby=BTV&product=AFD&format=CI&version=1&glossary=1

Otherwise, damaging winds are the main threat, with large hail
mainly confined to any rotating storms during the period.
Damaging winds may be more likely to uproot trees in today`s
event given saturated ground conditions areawide. Severe threat
gradually wanes across central/ern VT late this evening as
storms encounter weakening CAPE with onset of diurnal cooling
cycle.

We`ll need to watch the southern end of the potential convective
line, where some of the CAMs output and HREF suggest best
potential for training storms toward the end of the event this
evening. Thinking most rainfall is in 0.75-1" range, but
locally 1-1.5" and maybe localized 2" totals for Rutland/Windsor
counties if storms take on more of an NE-SW orientation
parallel to weakening deep-layer shear in the 00-03Z period this
evening. Low Flash flood guidance values - a function of
saturated antecedent soil conditions - of roughly 1.2-1.5" in 3
hours will potentially be exceeded with the type of intense
rainfall that these thunderstorms can produce. As such, Flood
Watch continues to look good, and will highlight greatest
potential of flash flooding is in s-central VT.

    July has arrived ... the Meteorologically defined mid summer month

    in New England

    Posted 

    https://forecast.weather.gov/product.php?site=BTV&issuedby=BTV&product=AFD&format=CI&version=1&glossary=1

Convective allowing models are consistent in their depiction of
convective initiation in vcnty of St. Lawrence County 18-19Z,
with convective storms moving steadily eastward through the late
afternoon hrs in nrn NY and across VT during the late afternoon
thru evening hours. Best vertical shear is in the sfc-700mb
layer, with excellent hodograph curvature and sfc-1km SRH values
exceeding 100 m2/s2, especially across nrn NY. Weakening mid-
level flow and shear suggests updrafts may rain back on
themselves later in the convective evolution, with potential for
storm mergers and upscale growth into a QLCS. Until that time
however, environment does support supercell development with
30-40kts of sfc-6km bulk shear and aforementioned strong low-
level SRH and high CAPE values. Can`t rule out an isolated
tornado or two, especially nrn NY ewd into the Champlain Valley,
where stronger southerly PBL flow will exist with terrain
driven channeling effects. Vermont averages one tornado per
year, and this is the type of convective environment that can
be conducive for isolated tornadoes to happen in our region.

    July 9th - 11th significant flood event

    in New England

    Posted

    My favorite part of the Governor's midday press conference was the guy who said they are still looking for the bridge that got washed out in Vershire.  He then added that they are not going to put it back when they find it but they would like to find it anyway.  (he was smiling as he added the second part)

    • Like 3

    July has arrived ... the Meteorologically defined mid summer month

    in New England

    Posted

    Flood watch issued for most of Vermont for tomorrow into Friday:

    https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=BTV&wwa=flood watch 

    Flood Watch
National Weather Service Burlington VT
1259 PM EDT Wed Jul 12 2023

NYZ028-031-034-035-VTZ003-004-006>011-016>021-130845-
/O.NEW.KBTV.FA.A.0003.230713T1800Z-230714T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Clinton-Western Clinton-Western Essex-Eastern Essex-
Orleans-Essex-Lamoille-Caledonia-Washington-Western Addison-
Orange-Western Rutland-Eastern Franklin-Eastern Chittenden-
Eastern Addison-Eastern Rutland-Western Windsor-Eastern Windsor-
Including the cities of Champlain, Plattsburgh, Dannemora,
Ellenburg, Lake Placid, Newcomb, Port Henry, Ticonderoga, Derby,
Newport, Island Pond, Lunenburg, Johnson, Stowe, Hardwick, St.
Johnsbury, Montpelier, Waitsfield, Middlebury, Vergennes,
Bradford, Randolph, Fair Haven, Rutland, Enosburg Falls,
Richford, Richmond, Underhill, Bristol, Ripton, East Wallingford,
Killington, Bethel, Ludlow, Springfield, and White River Junction
1259 PM EDT Wed Jul 12 2023

...FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT...

* WHAT...Flash flooding caused by excessive rainfall is possible.

* WHERE...In Vermont... Most of central and northern Vermont except
  Grand Isle, Western Chittenden, and Western Franklin Counties.  In
  New York... Essex and Clinton Counties.

* WHEN...From Thursday afternoon through late Thursday night.

* IMPACTS...Excessive runoff may result in flash flooding,
  especially along river and streams and in low-lying and
  flood-prone locations.

* ADDITIONAL DETAILS...
  - Additional rainfall is expected Thursday afternoon as a line
    of strong thunderstorms moves through. Rivers and streams are
    already running high and any additional rainfall will go
    straight to run-off in areas that have recently flooded.
    Additional forecast rainfall amounts for Thursday afternoon
    are 1 to 1.5 inches, locally up to 2 inches in the heaviest
    storms.
    • Like 1

    July 9th - 11th significant flood event

    in New England

    Posted

    Flood watch issued for most of Vermont for tomorrow into Friday:

    https://forecast.weather.gov/wwamap/wwatxtget.php?cwa=BTV&wwa=flood watch 

    Flood Watch
National Weather Service Burlington VT
1259 PM EDT Wed Jul 12 2023

NYZ028-031-034-035-VTZ003-004-006>011-016>021-130845-
/O.NEW.KBTV.FA.A.0003.230713T1800Z-230714T0600Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Eastern Clinton-Western Clinton-Western Essex-Eastern Essex-
Orleans-Essex-Lamoille-Caledonia-Washington-Western Addison-
Orange-Western Rutland-Eastern Franklin-Eastern Chittenden-
Eastern Addison-Eastern Rutland-Western Windsor-Eastern Windsor-
Including the cities of Champlain, Plattsburgh, Dannemora,
Ellenburg, Lake Placid, Newcomb, Port Henry, Ticonderoga, Derby,
Newport, Island Pond, Lunenburg, Johnson, Stowe, Hardwick, St.
Johnsbury, Montpelier, Waitsfield, Middlebury, Vergennes,
Bradford, Randolph, Fair Haven, Rutland, Enosburg Falls,
Richford, Richmond, Underhill, Bristol, Ripton, East Wallingford,
Killington, Bethel, Ludlow, Springfield, and White River Junction
1259 PM EDT Wed Jul 12 2023

...FLOOD WATCH IN EFFECT FROM THURSDAY AFTERNOON THROUGH LATE
THURSDAY NIGHT...

* WHAT...Flash flooding caused by excessive rainfall is possible.

* WHERE...In Vermont... Most of central and northern Vermont except
  Grand Isle, Western Chittenden, and Western Franklin Counties.  In
  New York... Essex and Clinton Counties.

* WHEN...From Thursday afternoon through late Thursday night.

* IMPACTS...Excessive runoff may result in flash flooding,
  especially along river and streams and in low-lying and
  flood-prone locations.

* ADDITIONAL DETAILS...
  - Additional rainfall is expected Thursday afternoon as a line
    of strong thunderstorms moves through. Rivers and streams are
    already running high and any additional rainfall will go
    straight to run-off in areas that have recently flooded.
    Additional forecast rainfall amounts for Thursday afternoon
    are 1 to 1.5 inches, locally up to 2 inches in the heaviest
    storms.

    July 9th - 11th significant flood event

    in New England

    Posted

    1 hour ago, tunafish said:

    Just awful.  Stating the obvious here but the recovery efforts are going to be $$$ and last for months.

    Vermont's topography and the fact that most towns are settled along the rivers in the valley make it a "perfect" candidate for significant flooding.  The water just has nowhere to go.

    And it's not like these are people building new multi-million dollar homes along the floodplains of prime hurricane country.  These are hundreds of years old settlements.  That is to say, you can't fault anyone for the losses they're experiencing.

    Vermont also has a massive housing shortage which will make it even harder on the displaced.

    • Thanks 1
    • Sad 1

    July 9th - 11th significant flood event

    in New England

    Posted

    2 hours ago, powderfreak said:

    I’m hearing I-89 might be messed up in both directions and closed for some time in that Montpelier to Waterbury stretch.

    It has reopened

    https://www.vermontpublic.org/live-updates/vermont-experiencing-significant-flash-flooding#interstate-89-reopens-in-montpelier-area

    Quote

     

    The Vermont Agency of Transportation says the Montpelier section of Interstate 89 has reopened.

    The stretch of roadway between Exit 7 in Berlin and Exit 9 in Middlesex is open again in both directions after closing overnight due to flooding.

    VTRANS says crews inspected the roadway this morning and cleared debris from the northbound lanes.

     

     

     

    • Like 3

    July 9th - 11th significant flood event

    in New England

    Posted

    1 hour ago, mreaves said:

    Wrightsville Dam was built in response to the 1927 flood.  There were a couple of others built as well in response to that flood, Little River in Waterbury and the East Barre Dam, not far from me.  I expect they are all pretty full.

    https://vtdigger.org/2023/07/11/montpelier-warns-that-wrightsville-dam-could-spill-over-imperiling-city/

    from that article is an shot of Montpelier this morning:

    downtown-Montpelier-Tuesday-morning-1536

    • Like 2
    • Sad 1
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