Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
1242 PM EDT sun may 3 2015
a broad ridge of high pressure will continue to provide the north
country with dry conditions and above normal temperatures into
early this upcoming week before cold front brings scattered
showers to the area. Isolated showers will be possible over the
mountains this afternoon. Temperatures behind the cold front will
drop back to near normal by midweek with dry conditions prevailing
until a warm front brings a slight chance of showers towards the
end of the week.
Near term /until 7 PM this evening/...
as of 1238 PM EDT Sunday...updated forecast to place slight chance probability of precipitation
across the eastern dacks and central cpv for this afternoon. Radar
showing widely scattered showers developing ahead of weak 500 mb vorticity
and associated middle level moisture. Given the very dry surface
conditions...not expecting much more than a few sprinkles in most
locations. Maybe a spot 0.01 or so in southern areas.
Otherwise...temperatures are warming quickly this afternoon...away from the
lake with btv already 76f. Thinking highs will range from the u60s
mountains to upper 70s to near 80f warmer valleys. Any brief shower
will quickly cool surface back into the 60s...but should warm back up
after shower passes and sun returns. Wind generally south to
southwest at 5 to 10 miles per hour.
Short term /7 PM this evening through Tuesday/...
as of 401 am EDT Sunday...overnight the period we will see very
similar results to Saturday night with light and variable to calm
winds under mostly clear skies allowing for good radiational
cooling to drop min temperatures across the region into the upper 40s to
low 50s in the valleys. The surface high pressure will still be
firmly entrenched Monday morning and thus we will continue to see
another day of above average temperatures likely being the warmest day of
the season thus far. Maximum temperatures will approach 80 degrees in the
Champlain Valley and upper 70s area wide. That will soon subside
though as a cold front looks primed to drop south from Quebec
bringing a scattered chance of showers across the area. The
coverage of the showers remains a bit of a question as the larger
global models bring a widespread path of showers however the
smaller higher resolution models show a line that falters as it
moves into the higher terrain of the Adirondacks. As such I
blended both coming up with more of a 40-60% chance in the higher
terrain with a 20-30% chance in the Champlain Valley. The
consensus of all the guidance is that the higher terrain
definitely does have the best chance to see the most rainfall.
Current quantitative precipitation forecast totals see about about 0.10" to 0.25" across most of
the area with the highest totals in the higher terrain of the
Adirondacks before the line potentially dissipates.
The other important feature is that the steep lapse rates leading
up to the cold front will likely bring some strong gusty winds.
That will combine with areas of low rh's however the overlap of
low rh's and gusty winds looks to be marginal so i'm not ready to
issue a Fire Weather Watch as of this forecast package.
Then Tuesday behind the front more seasonable temperatures will
return to the area seeing temperatures overnight will be in the in the
middle to low 50s warming to the middle 60s across the area during the
Long term /Tuesday night through Saturday/...
as of 356 am EDT Sunday...dry and Spring-like weather expected
through Thursday night.
European model (ecmwf) and GFS models in good agreement through the period.
Thus...forecaster confidence is high.
European model (ecmwf) and GFS models show a ridge of high pressure will build into
the region on Tuesday night and remain through Thursday night. On
Friday...both the European model (ecmwf) and GFS models showing a warm front will
build southeast from Canada into the region on Friday...so have gone
with slight chance probability of precipitation for rain showers on Friday.
A cold front will move south from Canada Friday night and
Saturday...so have gone with chance probability of precipitation for showers and
Aviation /18z Sunday through Friday/...
through 12z Monday...VFR conditions expected through the period
as a weak ridge of high pressure will be over the region.
Expecting some cumulus clouds to develop across the region today
between 13z-15z...as model guidance again showing steep low level
lapse rates across the region today. Expecting mainly clear skies
after 00z Monday.
Outlook 12z Monday through Thursday...
12z Monday-00z Tuesday...VFR conditions with weak high pressure
over the region.
00z Tuesday-12z Tuesday...mainly VFR but with areas of MVFR/IFR
in showers as a weak cold front moves through the region.
12z Tuesday-00z Friday...VFR conditions develop once again with
weak surface high pressure area building into the region through
the 60 to 90 day departure from normal precipitation shows a
deficit of 2 to 4 inches across most of northern New York into Vermont.
Dry conditions continue across our region with only a 10 to 20%
chance of an isolated shower on Sunday afternoon across central
and southern Vermont. Any precipitation today will be very light. A
cold front approaching the region from southern Canada will
increase the winds on Monday afternoon with breezy south to
southwest winds of 10 to 20 miles per hour with gusts between 25 and 35 miles per hour
expected. The strongest winds will be across the Saint Lawrence
valley...Champlain Valley...and exposed higher terrain of central
and northern Vermont. Meanwhile...minimum relative humidities
values will drop between 26% and 35% between noon and 4 PM on
Monday...before deeper moisture arrives associated with the cold
front. If the cold front arrives earlier than expected...than relative humidity
values will be higher especially across the northern Vermont and New York.
The lowest relative humidity values will be across central and southern Vermont on
Monday. These conditions combined with very dry fine fuels below
2000 feet and limited areas of green up per coordination with our
fire users...supports the potential for fire weather headlines on
Monday afternoon...if current trends continue. Still some
uncertainty on min rh's...timing of clouds/precipitation
associated with cold front and magnitude of wind speeds.
with warming temperatures this weekend its important to remember
that the lake and river waters are still quite cold. Below is a
reminder about cold water safety.
Early in the boating season...water temperatures on rivers...ponds
and lakes remain rather cold. Immersion in cold water can be life
threatening very quickly due to hypothermia and the bodies inability
to work efficiently in the cold water. Therefore...it is recommended
to consider postponing small craft boating activities until water
temperatures become warmer. However...if you choose to venture
out...wear all recommended cold water protective gear...including
a life jacket...in the event of an accident.
marine...weather forecast office btv