Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Burlington Vermont
731 am EDT sun Mar 29 2015
high pressure will build into the region continuing to bring clear
skies and cold temperatures today. To start the work week a cold
front will bring a chance of rain and snow showers to the area.
After a brief cool down Tuesday and Wednesday a warming trend will
lead to temperatures in the middle 40s to low 50s by the end of the week.
Near term /until 8 PM this evening/...
as of 722 am EDT Sunday...dry air is pushing into the area and
clear skies are all around from The View of the webcams across
the area. Other than the cold temperatures today will be beautiful across
the north country. Winds aloft are already beginning to shift
around from the north west to west thus beginning the trend of warming
throughout the morning. Other than the lovely Saranac Lake area,
who is currently at -9, temperatures are in the low teens and should
begin to start warming up quickly. The current forecast is in good
shape and only some minor cosmetic changes to temperatures/dew points and
wind speeds were made.
Previous discussion as of 326 am...broad high pressure will
continue to build into the region. An upper level ridge will build
into New England this afternoon bringing significantly drier air
in the middle levels. 1000-700mb relative humidity will be less than 40% through the
afternoon and into the early evening. The clear skies and shift in
winds from northerly to southwesterly will allow temperatures to warm
into the middle 30s today.
Short term /8 PM this evening through Tuesday/...
as of 326 am EDT Sunday...late Sunday night/early Monday morning
an Alberta clipper system will quickly push into the region with
decent qg forcing from 06z-18z. It will bring a slight chance of
snow showers Sunday night over northern New York before
overspreading into Vermont by early morning on Monday. Expect the
temperatures in the boundary layer to support complete melting of the
precipitation in valleys by 15-18z before changing back to snow by 00z in
the evening. Models showing steep low-level lapse rates and even
some low values of cape, so some gusty rain or snow showers may
accompany the cold front as it move through later in the day.
Temperatures during the day will warm into the low to middle 40s under
moderate and gusty south westerly flow of 25 to 30 kts with
Colder Post frontal northwest upslope flow develops and with
Froude numbers expected above 1 most of the snow shower expected
at the summits and slightly on the Lee side of The Greens. A
dusting to an 1 inch will be possible with a bit more on the
mountain summits. The biggest quantitative precipitation forecast region will be over northern New
York where 1-3" inches of snow is likely. The southerly flow
during the day on Monday will support continued warming to near
normal with highs in the middle 40s in the valleys and upper 30s
elsewhere. Expect lows overnight behind the cold front to be
similar to Sunday night in the middle 20s.
Tuesday behind the surface front an upper level trough will pass
through the region with north westerly flow which will provide
some orographic snow showers over the Adirondacks and The Greens.
Dont expect any showers over the valleys as the dynamic forcing
wont be very strong and the showers will have to depend on the
orographic lift to develop. Highs on Tuesday will stay on the
cooler side running in the middle 30s across the area.
Long term /Tuesday night through Saturday/...
as of 320 am EDT Sunday...a progressive upper flow regime is
expected to be in place across the northeastern Continental U.S. Throughout
the extended period. The period begins quiet as both the 00z European model (ecmwf)
and GFS indicate a surface ridge and building 700-500mb shortwave
ridge building eastward from the Great Lakes region Tuesday night. This
feature will bring mostly clear...but seasonably cool conditions
as we close out March and begin April. Good radiational cooling
potl Tuesday night should yield overnight lows mainly in the
teens. Highs on Wednesday will generally reach the middle 30s in
valley locations...with light winds and sunshine expected as surface
anticyclone crests over northern New York and Vermont with strong middle-level
As the surface ridge shifts east of New England Wednesday night...a
warm front will approach from the eastern Great Lakes...bringing
increasing clouds...breezy southerly winds...and a chance for some
light mixed wintry precipitation toward daybreak Thursday. Could see
some isolated to scattered rain showers during the day Thursday as
well...though best isentropic lift should move by with the front
early in the day. Good low-level warming expected Thursday...with
850mb temperatures +5 to +7c based on 00z GFS by 18z Thursday. Despite
potential cloud cover...should see temperatures near 50f in valley
locations for daytime highs.
Parent surface low passes well to our north and west...but trailing cold
front moving through the region Thursday night with potential for
additional frontal rain showers. Lows Thursday night should remain
in the middle 30s to near 40f (warmest in the Champlain valley). At
this point...overall quantitative precipitation forecast should be less than 0.50" given northern stream
shortwave and quick/progressive motion of surface cold front. While some
additional breakup of river ice is likely owing to extended duration
of above freezing temperatures...current indications suggest river
flows shouldn/T be particularly high to pose a flood threat with
this frontal system.
Some daytime low-level cold air advection on Friday...but with 850-700mb flow
remaining from the west-southwest...should still see highs in the middle to upper
40s for most sections. Some divergence in model solutions Friday night
and Saturday...as 00z European model (ecmwf) stalls frontal zone across eastern New
England with potential wave low causing additional shower activity.
The 00z GFS is more progressive...suggesting clear and dry
conditions for Friday night and Saturday. At this point...stayed close
to broader average of solutions with slight chance of light snow
showers Friday night...and 20 probability of precipitation for rain/snow showers on Sat.
Aviation /12z Sunday through Thursday/...
through 12z Monday...VFR expected through at least 06z Monday.
Clear skies with light winds through this morning. Winds become
light S-SW this afternoon as high pressure begins to shift east of
Vermont. Valley channeled flow will allow for some southwesterly gusts to
20 kts at kmss. High clouds ahead of northern stream trough will
result in increasing cirrus clouds this afternoon...then broken-
ovc120-150 tonight. Winds will begin to increase overnight as
southerly gradient flow increases. Winds at btv increase to
12-16kts after midnight with gusts to 26 kts expected. Scattered
light snow shower activity advances eastward across northern New York toward
daybreak Monday...with intervals of MVFR visibility possible at slk/mss
near the end of the taf period.
Outlook 12z Monday through Thursday...
12z Monday through 06z Tuesday...periods MVFR ceilings/visibility in rain
or snow showers with low pressure system moving west to east out
of Great Lakes.
06z Tuesday through 00z Wednesday...mainly VFR conditions...but
localized MVFR with scattered mountain snow shower activity (possibly
including slk/mpv) Tuesday morning. Hir terrain obscured at times.
00z Wednesday through 12z Thursday...mostly clear with high
pressure in place.
12z Thursday through 00z Friday...MVFR ceilings/visibility possible in
scattered rain showers ahead of approaching low pressure system.