Scientific Forecaster Discussion
fxus61 kbtv 271918
Area forecast discussion
National Weather Service Burlington Vermont
318 PM EDT Thu Apr 27 2017
a band of showers with a rumble of thunder will move from west to
east across the north country late tonight into early Friday
morning. Rainfall will be generally under a quarter of an inch with
any lingering showers moving east of our area by midday Friday.
Temperatures will remain mild for Friday into Saturday...before
another cold front produces more showers and cooler temperatures
Saturday afternoon into Sunday.
Near term /through Friday/...
as of 314 PM EDT Thursday...forecast focus tonight will be timing of
a band of rain showers moving from west to east...along with an
embedded rumble of thunder. Big picture shows mid/upper level
trof lifting across the Great Lakes with trailing ribbon of mid
level moisture and associated weakening 5h vort lobe. Taking a
model blend between NAM/GFS shows best 850 to 500mb moisture and
weak 700 to 500mb Omega couplet across our western cwa around
06z...into the cpv around 09z...and over eastern Vermont around 12z
Friday. Have utilizing pops from model reflectivity to display
this timing in our grids/forecast overnight...with a 1 to 3 hour
window of likely to Cat pops. Have continued to mention schc
for a rumble of thunder...best cape profiles of 400 to 800 j/kg
is located over nny around 06z...with an axis of -1 to -3
showalter values shifting from west to east across our region
overnight. The combination of some dynamics and elevated
instability support the schc wording. Qpf will generally be
between 1 and 2 tenths of an inch...maybe a few higher values in
convective elements over northern New York. Still anticipating low
level southeast winds to advect additional low level moisture
back into central/eastern VT overnight with low clouds
prevailing. These clouds will lift as winds shift to the
west/southwest on Friday. Temps mainly in the upper 40s to near
On Friday...mid level dry slot develops along with weak ridge of
high pres under west/southwest flow aloft. Progged 925mb to 850mb
temps shows a sharp NW to se gradient across our cwa with temps near
5 to 6c slv to 16c near vsf...which support mid 60s west to near 80f
vsf and lower parts of the cpv. A few light lingering shower are
possible across eastern VT thru 15z...but most of the area will
remain dry with above normal temps prevailing. Good mixing and
progged 850mb winds between 35 and 40 knots...support some localized
wind gusts to 30 knots...especially in channeled flow over the
Short term /Friday night through Saturday night/...
as of 314 PM EDT Thursday...fast moving flow aloft will exist over
the area through the period. Friday night starts off dry...but
then surge of moisture moves in during the first part of
Saturday and brings showers to the area before exiting to the
east late in the day. Saturday night will be dry once again.
Despite the precipitation on Saturday...much of the area will
see above normal temperatures...especially from the Champlain
Valley eastward. Highs on Saturday will be in the lower 60s to
Long term /Sunday through Thursday/...
as of 314 PM EDT Thursday...high pressure will be over the area Sunday
morning with this feature moving east during the day. A frontal
boundary will move into the region late in the day and increase
the chances for some showers late in the day over northern New
York. The front will move toward the Canadian border Sunday
night into Monday with the best chances for precipitation over
the far northern portions of the area. Eventually a cold front
moves into the area Monday night into Tuesday and showers will
be more likely across the entire area. This will be our best
chance for higher precipitation amounts as moisture from the
Gulf and Atlantic should move up into the region. Temperatures
will be warm enough aloft to promote some high elevation
snowmelt and we should see some noticeable rises on area
waterways. Unsettled weather continues Tuesday through Thursday
as upper trough lingers over the northeast. Warmest temperatures
should be on Monday with temperatures trending toward more
seasonal values for the remainder of the week.
Aviation /19z Thursday through Tuesday/...
through 18z Friday...vis satl continues to Show Low clouds and
MVFR cigs at mpv/rut this afternoon...thinking these cigs will
lift to VFR by 20z...with the rest of the taf sites experiencing
VFR conditions. Tonight...soundings Show Low level southeast
flow will advect moisture back into mpv with cigs trending from
VFR to MVFR to IFR after 06z. Meanwhile...mid/upper level clouds
increase from SW to NE ahead of boundary this evening...with a
period of light rain showers between 06z-12z. A brief period of
MVFR cigs/vis possible with fropa overnight...along with a
rumble of thunder at slk/mss. Otherwise...breezy south winds at
10 to 20 knots with local terrain impacts will shift to the
southwest/west by Friday morning...with VFR conditions
Friday: VFR. Breezy. Slight chance rain showers.
Friday night: VFR. Slight chance rain showers.
Saturday: VFR. Chance rain showers...tsra.
Saturday night: VFR. No sig weather.
Sunday: VFR. Slight chance rain showers.
Sunday night through tuesday: VFR. Chance rain showers.