Scientific Forecaster Discussion
fxus61 kcar 070559
Area forecast discussion
National Weather Service Caribou ME
issued by National Weather Service Gray ME
1259 am EST Sat Dec 7 2019
low pressure will track across the Gulf of Maine tonight.
High pressure will build across the region later Saturday
through Sunday. A warm front will cross the region later Sunday
night through early Monday. Low pressure will track northwest of
the region Tuesday. A cold front will cross the region Tuesday
night through early Wednesday.
Near term /until 6 am this morning/...
update...clouds continue to depart to the east as clipper moves
into the Canadian Maritimes. Some upslope cloudiness will
continue over the higher terrain. Made minor adjustments to
temperatures and winds with this update. Otherwise, little
change to the overall forecast package.
930 PM update: latest radar ref imagery already
indicating a break down of lgt stratiform snfl alg the immediate
downeast coast as the clipper sfc low and S/WV tracking well S
of our forecast area weakens. Most if not all of snfl ovr this area will
end by or shortly after mdngt. Otherwise, trends seen latest
obsvd sfc temps/dwpts were used to update hrly fcst values of
each into the late ngt with reductions to fcst ovrngt low temps
made ovr some nrn Vly lctns due to thin cld cvr allowing sfc
radiational cooling with sig sfc based invsns. Uncertainty
exists in how long sfc base invsns ovr these areas will hold
with grad sfc winds xpctd to increase somewhat late tngt as the
sfc pres grad tightens and llvl cold advcn increases behind the
clipper S/WV Alf.
Orgnl disc: right as low is exiting, winds come around to the
northwest. Low temps in the north fall to the single digits, with upper
teens along portions of the coast. Snow showers will diminish
by morning as rear of mid-level jet passes through. The exiting
low pressure lifts east of Nova Scotia, surface high pressure
will build in northwest flow. Temps in most locations on Sat cooler in
Short term /6 am this morning through 6 PM Sunday/...
high pressure will cross the region Saturday night with
decreasing clouds north, mostly clear skies downeast. High
pressure exits to the east Sunday with a mostly sunny morning
then increasing clouds during the afternoon. A cold front will
extend from the Great Lakes across central Quebec province
Sunday night, with a warm front crossing the region later Sunday
night through early Monday. Expect a chance of snow north, with
a slight chance of snow/rain downeast, Sunday night with the
warm front. The cold front will remain nearly stationary Monday
while low pressure intensifies along the front across the Great
Lakes and tracks northeast. Warmer air will steadily move north
across the region Monday. Across downeast areas a brief
rain/snow mix is possible early Monday, though precipitation
will be mostly in the form of rain. The snow will transition to
rain, from south to north, across the remainder of the region
through the morning into early afternoon. A brief interval of
sleet or freezing rain is possible across northern areas during
the transition. Generally expect snow accumulations up to
around an inch across much of northern Maine before the
transition to rain, with 1 to 2 inches possible across the
Saint John valley. A slower transition to rain could allow
slightly greater snow accumulations. Precipitation should be in
the form of rain across the entire region by mid afternoon.
Temperatures will be at below normal levels Sunday. Low
temperatures Sunday night will occur early, then begin to warm
overnight. Temperatures will warm to above normal levels Monday.
Long term /Sunday night through Friday/...
the low will track northeast along the cold front, across
Quebec province, Monday night through Tuesday with warm
advection persisting across the forecast area. Temperatures will
be near steady Monday night. Precipitation will remain in the
form of rain Monday night through Tuesday along with melting of
the snowpack. A cold front will cross the region Tuesday night
through early Wednesday. The steadier precipitation will exit
across the Maritimes in advance of the cold front. Any lingering
precipitation will transition back to snow or snow showers
following the cold front. An upper level trof will approach from
the west Wednesday then cross the region Wednesday night
through early Thursday. A disturbance moving through the trof
could bring a chance of light snow or snow showers later
Wednesday into Wednesday night. High pressure should build
across the region Thursday, then exit to the east Friday. An
upper level disturbance/surface trof could bring a chance of
snow showers Friday. Temperatures will be at much above normal
levels Tuesday. Temperatures will fall Wednesday following the
cold front, with much below normal level temperatures
Aviation /06z Saturday through Wednesday/...
near term: VFR across the north tonight with west winds
continuing, but decreasing. Bgr and bhb will see snow showers
this evening and overnight. Expect MVFR in these showers, with
possible IFR at bhb. Winds light and from the west-northwest.
Sunday...generally VFR. MVFR possible late across northern
Sunday night...VFR/MVFR early. Lowering to IFR/LIFR
overnight with a chance of snow north and a chance of snow
and rain downeast.
Monday...IFR/LIFR. Precipitation changing to rain from south
to north through early afternoon. Gusty south winds.
Tuesday...IFR/LIFR with rain. Gusty south winds.
Tuesday night...IFR/LIFR with rain and gusty south/southwest
winds in advance of a cold front. The cold front crosses much
of the region Tuesday night with precipitation transitioning
to snow or snow showers following the front.
Wednesday...the cold front exits across the remainder of the
region early Wednesday. IFR/LIFR early, then MVFR/IFR during
the afternoon. Snow or snow showers following the cold front.
near term: Small Craft Advisory has been extended a few hours into Saturday
morning as wind gusts remain at or above Small Craft Advisory criteria, 25kts.
Waves will remain about 2 to 4 feet through this period.
Short term: Small Craft Advisory conditions possible early
Saturday night. Conditions briefly below Small Craft Advisory
levels later Saturday night through early Sunday, with Small
Craft Advisory conditions then developing later Sunday. Gale
force wind gusts are possible Sunday night into Monday.
Visibilities will be reduced in rain Monday.
Marine...Small Craft Advisory until 9 am EST this morning for