Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
348 am EST sun Feb 14 2016
the coldest air of the winter will move over the region today.
High pressure will slowly build across the region into Monday.
Low pressure will track west of the region Tuesday.
Near term /through tonight/...
snow showers will end in the next few hours as the upper level low
moves east and high pressure builds. Northwest winds will
continue all day with highs below zero in a large part of
Aroostook County. Elsewhere...highs will be in the low single
digits. The wind chill warning will likely need to be converted to
an advisory through Sunday evening for northern zones. The
existing Wind Chill Advisory for the southern part of the forecast
area will likely expire later this morning...but wind chills will
remain in the minus 10 to minus 20f range. The high builds over
night...but winds seem unlikely to become calm and allow full
decoupling. However...the air is cold enough to produce minus 10
to minus 15f readings over most of the area. The Allagash will see
readings closer to minus 20 and the coast will be in the zero to
minus 5 range.
Short term /Monday through Tuesday night/...
surface ridge axis will be over area by 12z Monday. Winds will be backing from
the west to the south drg the course of the day, allowing for warmer
temperatures to be drawn back into the area. High will aprch the l/M teens
across the north to m20s along the coast for afternoon maxes. 500 mb ridge will
be keeping weather at Bay throughout the day as next system is coming
onshore in western British Columbia at this time.
Isentropic upglide on the 285k layer per both the NAM and GFS does not
really get going across southern and western sections of County Warning Area until 00z Tuesday. All medium
range guidance is holding off on quantitative precipitation forecast until closer to 06z Tuesday and
with overrunning setup will allow for chance probability of precipitation just beginning to
encroach on County Warning Area by 00z.
Warm air advection advection will kick in Monday night with temperatures rising through the night.
Mins for Tuesday morning will likely be right around 00z before h9 winds
strengthen to between 25 and 30kts. After 06z Tuesday expect widespread quantitative precipitation forecast
to be ongoing over County Warning Area as low level jet kicks in. Significant amnts of warm air
being drawn in from the Atlantic will result in quick transition from
liquid to frozen precipitation through the day.
Latest 00z medium range guidance, with the exception of the NAM, tracks
surface low to our west on Tuesday with European model (ecmwf) being the slowest.
Majority of GFS ensemble members are now trending west with track of
low. Expect all zones to start off as snow by 06z with rain
beginning to mix in along the coast before 12z. Brief period of -fzra across
central sections around 12z then progressing north from there before becoming all
rain after 18z. This solution is a compromise between 00z GFS, which tracks
the low to our west, and 00z NAM, which bisects County Warning Area.
Expect that if NAM also tracks west that the transition will be much
quicker with very little snowfall at the start. As it stands now just
minimal snow accums along the coast with around 4-6 inches across northern
zones over a 24-hour period.
Maxes on Tuesday will top out around 40f in the north to around 50f along the
coast. This looks as though it will fall about 5 degrees short of a
record for Tuesday.
Precipitation winds down between 06z and 12z Wednesday as low rapidly pulls off to
the northeast. Expect just a brief period of snow showers at the end
of the event with only minor accumulations expected in wrap-
Long term /Wednesday through Saturday/...
upper level trough will skirt through by 00z Friday with potential for chance
snow showers continuing for the early part of the long term. 500 mb
ridge will bring quiet weather to the County Warning Area starting Friday morning before next
storm winds up back to the west early in the weekend. Event for
Saturday looks similar with warm advection possibly resulting in
mixed precipitation drg the day then switching back to snow overnight.
Aviation /08z Sunday through Thursday/...
near term: VFR conditions are expected at all terminals through
Sunday night with high confidence.
Short term: VFR expected at the beginning of the short term under
high pressure. MVFR restrictions will approach southern terminals
by 03z Tuesday and after 06z across the north. Expect a period of IFR
in snow and mixed precipitation between 06z and 12z in bhb and bgr and all
snow over northern terminals. By 15z Tuesday southern terminals will
likely be all rain with northern terminals transitioning over to
mixed precipitation and eventually rain. IFR will continue through Wednesday
morning before becoming MVFR and occasionally VFR.
near term: may have to end the gale later in the morning as winds
are a bit lighter than expected. However...with the strength of
the cold air mass moving over the relatively warm waters...will
want to see the trends over the next six hours. The heavy freezing
spray headline looks good at this point with an end time at 10am.
Freezing spray will continue and will likely transition to a
freezing spray advisory.
Short term: Small Craft Advisory conditions expected Monday evening with strong southerly
winds ahead of approaching system. Gale force winds likely late
Monday night into Tuesday with Small Craft Advisory for seas through the end of the period.
ME...wind chill warning until 10 am EST this morning for mez001>006-
Wind Chill Advisory until 10 am EST this morning for mez011-
Marine...heavy freezing spray warning until 1 PM EST this afternoon for
Gale Warning until 4 PM EST this afternoon for anz050>052.