Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
345 am EDT Tuesday Sep 23 2014
an upper level trough across Quebec and northern New England will
bring variable amounts of cloudiness across the north country
today...with a few sprinkles possible across the mountains. Skies
will clear out tonight as a high pressure amplifies at the surface
and aloft across the northeastern United States. This large area of
high pressure will bring dry weather with warming temperatures right
through next weekend.
Near term /until 7 PM this evening/...
as of 326 am EDT Tuesday...mean 500-300mb trough axis bisects the north
country early this morning...with 06z rap analysis indicating
upstream 80-90kt jet across southeastern Ontario. The upstream jet is
associated with a middle-level vorticity and area of cloud cover across
Ontario...which will move in across northern New York later this morning per
prognosticated RUC/NAM relative humidity trends. Also dealing with lingering stratus
layer across much of Vermont with ceilings around 5 kft early this
am. On balance anticipate mostly cloudy conditions...with some
sunny breaks this afternoon especially across S-central Vermont. May
see a couple of sprinkles from the stratus layer...mainly across the
northern Adirondacks and northern Green Mountains during the day...but not
anticipating any measurable rainfall. Despite limited
sunshine...high temperatures will generally reach the low-middle 60s
this afternoon...which is about 10 degrees warmer than where
temperatures hovered much of the day Monday. Winds will generally
remain SW-west at 5-10 miles per hour.
Short term /7 PM this evening through Thursday/...
as of 326 am EDT Tuesday...skies are expected to clear out tonight as
deep-layer ridge builds in from the west and final shortwave
trough departs well to the north and east. This will begin an
extended period of dry weather conditions across the north
country. Skies will generally be clear...but will see nocturnal
fog each night in the favored river valleys. Also...may see some
middle-upper level clouds on Thursday. Clouds will be associated with
cut- off upper low which is now prognosticated by 00z GFS/NAM to move from
the southeastern Atlantic coast a bit further up the middle-Atlantic coast.
Still looks like any precipitation will stay south of our region.
High temperatures will moderate through the period and be well
above normal for late September. Highs generally in the low 70s on
Wednesday and low-middle 70s for Thursday...except possibly a bit
cooler in S-central Vermont depending on potential cloudiness. Winds
will be relatively light...becoming light southeast to south
Wednesday and Thursday as center of surface anticyclone shifts
east of the north country. Overnight lows will range from the upper
30s to middle 40s tonight...and generally in the 40s Wednesday night.
Long term /Thursday night through Monday/...
as of 340 am EDT Tuesday...much above normal temperatures expected as
large scale synoptic ridge prevails across the eastern Continental U.S.. all
models and latest ensemble data in good agreement with this
scenario for Friday through the upcoming weekend. Expecting a
large swing in diurnal temperatures...given the deep dry air in place
across our County Warning Area...especially over the weekend. Prognosticated 850 mb temperatures
warm between 13-15c on Sat/Sunday...which support highs well into the
70s...with a few lower 80s possible in the warmer valleys. Have
bumped temperatures 2 to 5 degrees above the super-blend values. Lows will
range in the 40s colder mountain valleys to middle 50s cpv/slv...with
light terrain driven winds. By late Sunday into Monday...both the
GFS/European model (ecmwf) hint at a back door front approaching our northern County Warning Area.
This feature will have limited moisture...with strongest low level cold air advection
occurring across northern Maine...where best hght falls happen
associated with digging middle/upper level trough. Will mention schc/low
chance wording in the grids across our northern County Warning Area...but quantitative precipitation forecast amounts
will be light. Prognosticated 850 mb temperatures drop between 9-11c...supporting highs
in the u60s northern mountains to middle 70s.
Aviation /08z Tuesday through Saturday/...
through 06z Wednesday...VFR conditions will continue at all taf sites
through 06z Wednesday. Surface high pressure is located across the Ohio Valley with
west to northwest upslope follow across our taf sites. This combined
with several pieces of energy...has resulted in scattered to
broken clouds across many of our taf sites. Per latest sounding data
expect a broken cloud deck today at 4000 to 6000 feet with west
winds shifting to the south/southwest today at 5 to 10 knots. Some
higher gusts will be possible in the SW to NE aligned
slv...impacting mss. Otherwise...skies will clear this evening with
light terrain driven winds developing after 00z.
Outlook 06z Wednesday through Saturday...
surface high pressure will result in clear skies and VFR conditions for Wednesday
into Thursday...with some patchy fog possible with IFR conditions at
mpv/slk on Thursday morning. Some clouds increase on Thursday
associated with sub-tropical moisture...but showers should stay
south of our taf sites. VFR conditions will prevail into the
weekend...with light winds