785
FXUS61 KBTV 271123
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
723 AM EDT Tue Jun 27 2017
.SYNOPSIS...
Showers will becomE rather widespread during the late morning
and afternoon hours today across the entire area. Also...the
potential for thunderstorms will exist and gusty winds and small
hail will be possible with any of the storms. The showers and
storms end tonight and much of the area will be dry on Wednesday
with just the possibility of some showers up along the
international border. Below normal temperatures will continue
through midweek...but a warmer and wetter pattern sets up for
the rest of the week and into the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 723 AM EDT Tuesday...Overall forecast in good shape with
no real changes needed at this time. The dry weather this
morning will be short-lived as well defined shortwave trough
moving out of the eastern Great Lakes early this morning is
enhancing convection over western New York state. This feature
moves across our area during the late morning and afternoon
hours and increase dynamic support across the region for greater
areal coverage of showers and isolated storms across our area.
Going forecast of convection ramping up into the likely category
looks real good. Colder core aloft associated with the
shortwave trough will steepen lapse rates over the area and
despite cooler temperatures today...sufficient instability will
develop with CAPE values in the 200-500 J/kg range. Low wet bulb
zero values and layer of drier air in the sub-cloud region both
point to gusty winds and small hail with any of the stronger
convection. Going forecast already has this in and will continue
to maintain. A Special Weather Statement has been issued to
highlight the threat of stronger storms.
The showers will end across northern New York in the early
evening hours and then across Vermont by midnight. Surface high
pressure builds into the region behind the departing upper
trough tonight and Wednesday. Any forcing will remain north of
the border on Wednesday and thus most of the area should remain
dry. Could see a few showers up along the international border
Wednesday afternoon. High temperatures will actually be a few
degrees warmer than today with highs in the upper 60s to lower
70s...which is a few degrees cooler than normal for this time of
year.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 423 AM EDT Tuesday...Any Wednesday afternoon convection
dissipates going into the evening and overnight hours with the
loss of surface heating and a weak ridge of surface high
pressure building over the region. As such, it should be a
relatively quiet night, and likely the last of the week with
active weather quickly returning Thursday as low pressure moving
through the Great Lakes will push a west/east oriented warm
front over the region. Showers develop along the boundary across
northern New York during the morning, and become widespread
across the entire forecast area through the afternoon and into
Thursday night. Tricky forecast in regards to thunderstorm
potential as surface instability is quite weak Thursday morning
to mid-day when 0-6km shear is the strongest (60-70kts), but as
the warm front begins to slowly lift northward during the late-
day and overnight hours instability actually increases while
the shear decreases. As such, feel thunderstorm potential will
be greatest across central/southern areas during the late
afternoon to around midnight, with coverage decreasing towards
daybreak Friday as the North Country becomes entrenched in the
warm sector.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 423 AM EDT Tuesday...By Friday morning the aforementioned
warm front will be lingering around the international border
with the majority of the North Country firmly in the warm
sector. Over the next 24-48 hours several waves of low pressure
riding along a cold frontal boundary to our west will provide
ample instability for showers and thunderstorms along with
additional moisture and PWATs surging to 1.5-2". While the exact
timing of each individual wave is difficult at this time,
confidence is growing high that periods of heavy rain from
Friday afternoon through Saturday night are likely with
additional rainfall amounts in the 1-2" range on top of the 1"
we`re likely to see on Thursday. Considering how wet area soils
are already, this could be the tipping point to realize flash
flood potential and bears watching through the week.
Sunday remains showery, especially across northern areas as the
parent upper trough and surface cold front look to swings through
the region, with quieter and drier conditions expected Monday post
fropa.
&&
.AVIATION /11Z TUESDAY THROUGH SATURDAY/...
Through 06Z Wednesday...Showers and isolated thunderstorms will
move from southwest to northeast across the entire area between
16z and 02z. Note the potential for gusty winds...variable
winds at 25 to 35 knots...and small hail... generally less than a
half inch in diameter...will be possible with any of the
storms. The time period most likely for this activity will be
from 16z through 22z. Any showers and storms will quickly be
ending between 00z and 04z. Expect VFR conditions through the
period...with localized MVFR/IFR conditions near the showers and
storms. Winds will generally be from the south and southwest
through the period.
Outlook...
Wednesday: VFR. Slight Chance SHRA.
Wednesday Night: VFR. Slight Chance SHRA.
Thursday: VFR/MVFR. Occasional SHRA.
Thursday Night: MVFR. Likely SHRA...Likely TSRA.
Friday: VFR. Chance SHRA...Chance TSRA.
Friday Night: VFR. Chance SHRA...Chance TSRA.
Saturday: VFR/MVFR. Likely SHRA...Chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Evenson
NEAR TERM...Evenson
SHORT TERM...Lahiff
LONG TERM...Lahiff
AVIATION...Evenson
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