000
FXUS61 KBTV 192301
AFDBTV
Area Forecast Discussion
National Weather Service Burlington VT
701 PM EDT Thu Jul 19 2018
.SYNOPSIS...
High pressure will prevail over the region tonight through Saturday
bringing dry weather...plenty of sunshine... and above normal
temperatures. The pattern is expected to change Saturday night when
southerly low level flow develops and brings deeper moisture into
the region. This will lead to increasing chances for rain late
Saturday and especially on Sunday.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
As of 325 PM EDT Thursday...Northwest flow aloft today has
helped to maintain dry air over the region and keep skies
essentially clear. Some very shallow cumulus has tried to
develop but lack of moisture and subsidence from high pressure
over the area has helped to limit any cloud develop. With high
pressure over the area winds have generally been light and
variable...and this also helped to develop some lake breezes on
either side of Lake Champlain. Clear skies and light winds are
expected tonight but temperatures should not get as low as last
night. Lows will generally be in the 50s with 40s in the
mountains. There may be some fog later tonight...especially at
Saranac Lake, New York and some of the favored locales of
eastern Vermont.
Sunny and dry weather continues for Friday with high pressure at the
surface and aloft. Air mass is still on the dry side and with
warming 925 millibar temperatures looking at highs in the 80s to
around 90. We should see the low level flow gradually turning to the
south Friday night. Dry weather will continue...but lows will range
from the mid 50s to mid 60s with a few upper 40s in the
mountains.
&&
.SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/...
As of 325 PM EDT Thursday...Southerly flow aloft becomes more
established across the region Saturday and especially Saturday
night. We should start to see an increase in clouds and
eventually an increase in precipitation chances late Saturday
night and especially early Saturday morning when pronounced
southerly flow aloft develops ahead of a slow moving upper
trough. More clouds/deeper moisture on Saturday suggest high
temperatures will not be as warm as Friday...but still looking
at upper 70s to mid 80s. Lows Saturday night will be in the mid
50s to lower 60s with a high likelihood for precipitation after
midnight Saturday night.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As of 325 PM EDT Thursday...The long term forecast continues to
look very unsettled, characterized by a moist, tropical air
mass over the North Country and a long-duration of showery/rainy
weather. Vertically-stacked low pressure over the Ohio River
Valley will continue to drop southward through the day Sunday,
further amplifying the longwave pattern over the eastern US and
resulting in a long fetch of southerly/southwesterly flow into
New England. Downstream of the low, models have consistently
keyed in on the strengthening of a southerly wave and the
development of an associated surface low forming off the
Carolina Coast Saturday and tracking northward to New England
Sunday. This feature should bring some more focused
precipitation and some higher winds to the North Country Sunday
morning, although the more precise timing, placement, and QPF
amounts are still yet to be determined. The track of the low and
the resultant strong southeasterly winds ahead of it would
favor a high PoP, low QPF event for the Champlain and
Connecticut Valleys as a result of rain shadowing. Higher
elevations, however, will not be rain shadowed and will see
higher QPF amounts. Precipitation should temporarily wane Sunday
night as weak shortwave ridging builds in. By Monday afternoon,
a Bermuda High will build over the western Atlantic, while a
broad upper low will gyrate over central Canada. The net result
of this will be continuous southwesterly flow from the
southeastern United States through New England, funneling
impressive moisture into the area between the two steering
features. PWATs are forecast to be in excess of 1.7" (greater
than 90 percent of the climatological daily average...) from
Sunday all the way through Wednesday. Under this setup, any weak
disturbances moving through the flow will trigger showers and
thunderstorms with locally heavy rainfall, particularly in the
afternoons when the atmosphere will be the most unstable, so
have kept PoPs generally above 50 percent Sunday through
Wednesday.
Precipitation this weekend/next week will be beneficial for the
area, but will also have to be monitored for flooding potential. The
US Drought Monitor has the North Country ranging from
"Abnormally Dry" to a "Moderate Drought", so the area will be
able to absorb quite a bit of rainfall before flooding becomes a
concern. Nevertheless, anytime we see a setup like this, the
potential for some flash flooding could exist and will be
monitored.
High temperatures in the long term will be generally in the upper
70s to mid 80s, with uncomfortably high dewpoints in the upper 60s
to low 70s. Lows will be 60s to low 70s.
&&
.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
Through 00Z Saturday...VFR through the forecast period. Only
exception will be a brief 3-4 hour window from 07-11Z Friday
during which some patchy MVFR/IFR mist/fog will be possible at
KSLK/KMPV (confidence highest at KSLK). Winds generally light
and variable overnight, trending south/southeasterly from 5 to
10 knots after 12Z Friday.
Outlook...
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
Saturday Night: VFR. Chance SHRA.
Sunday: Mainly MVFR, with areas VFR possible. Chance SHRA.
Sunday Night: Mainly VFR, with areas MVFR possible. Chance SHRA.
Monday: Mainly VFR, with areas MVFR possible. Likely SHRA, Likely
TSRA.
Monday Night: Mainly VFR, with local MVFR possible. Chance SHRA,
Slight chance TSRA.
Tuesday: Mainly VFR, with areas MVFR possible. Likely SHRA,
Chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Evenson
NEAR TERM...Evenson
SHORT TERM...Evenson
LONG TERM...RSD
AVIATION...JMG
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