Scientific Forecaster Discussion
fxus61 kcar 252219
Area forecast discussion
National Weather Service Caribou ME
619 PM EDT sun Jun 25 2017
a trough of low pressure will remain to our west this week.
Occasional disturbances tracking out of this trough and across our
area will bring periodic chances for showers and thunderstorms.
Near term /through Monday/...
6:19 PM update...isolated to scattered showers continue to
track northeast across parts of the County Warning Area early this evening. A
couple of lightning strikes, but thus far nothing too
impressive. There likely will be a few thunderstorms this
evening, but the chance of anything turning severe is small as
MUCAPE values are mostly less than 300 joules per the latest Storm Prediction Center
mesoscale analysis Page. Will maintain the enhanced wording for
small hail and gusty wind, but feel this threat is small and
will be very isolated. Made some minor tweaks to the forecast
based mostly on the latest observations and radar trends.
some showers have been popping up this afternoon across
northern and western areas as upper jet streak has been
enhancing these showers. Satl WV imagery coupled W/the lightning
display showed a disturbance move ENE W/some lightning activity
across southern Quebec and New Hampshire. This activity will lift ENE into
the evening. The latest meso-analysis showed the best
instability into the N and W but this looks to change by later
in the afternoon into the evening. Rap soundings showed convective available potential energy
hitting 400-500 joules across central and western areas W/steep
lapse rates and 0-6km shear of 25 kts. Decided to keep enhanced
wording(winds/hail) into the evening W/the stronger cells.
Activity will wind down across the central and downeast areas
later in the evening. More showers and perhaps a tstm for the
northern 1/2 of the County Warning Area later on as a cold front residing back
across Quebec apchs the region overnight. The best forcing
appears to be across northern Aroostook County. Temps will cool
down behind the front across far northern and western areas as
the front moves across that region Monday morning W/upper 40s to
around 50. The rest of the County Warning Area will be in the 50s.
The front is expected to slide into eastern areas by mid morning
Monday W/showers across the eastern areas. The front is forecast
to slide further S during the day on Monday as shown by the NAM
GFS and Canadian Gem and weaken. Some weak forcing was noted
especially by the GFS to keep some showers going into Monday
afternoon across the downeast areas. Decided on 20-30% pops
using a blend of the guidance. Rainfall for this term will be
0.10 inch or less except W/any tstms.
Short term /Monday night through Wednesday/...
an upper level trough and weak surface low will be centered to our
west, just north of the Great Lakes Monday evening. The trough will
remain to our west through the middle of next week bringing
occasional chances for showers. A weak disturbance running out of
the trough and across our area late Monday night into Tuesday will
bring a good chance for showers and some thunderstorms. The most
likely focus of the showers will be along a weak surface frontal
boundary across the north central part of our area on Tuesday.
Showers would likely diminish Tuesday night. However, another
similar disturbance kicking out of the Great Lakes trough will come
along on Wednesday and bring a renewed chance for showers and
thunderstorms. Central and northern areas look favored again.
Forecast CAPES both Tuesday and Wednesday look similar, around 500
j/kg across the north and a little less downeast.
Long term /Wednesday night through Sunday/...
the weather disturbance crossing the area on Wednesday will lift
away Wednesday night as a small high builds in behind it. The
mid- week period will then feature a Big, Warm and humid high
pressure system off the southeast coast and big, cool and dry
high pressure system over Hudson Bay. A well defined frontal
boundary in the trough over the Great Lakes will Divide the two
and provide focus for convergence. Moisture converging in this
front will stream east into our area on Thursday ahead of a
large surface low squeezed between the two highs. This will
bring a chance for some rain late Thursday into Friday. The
boundary may push south late Friday into Saturday before the
main body of the surface low lifts north, to our west, late
Saturday into Sunday. This has the potential to carry a lot of
moisture north along the boundary bringing a chance for a
soaking rain over the weekend.
Aviation /22z Sunday through Friday/...
near term: looks like VFR for all terminals into Monday outside
of any convection with briefly lower ceilings and visibilities.
Across some of the northern terminals from khul to kfve as cigs
could hit MVFR for a brief time Monday morning W/the arrival of
the cold front.
Short term: VFR conditions Monday evening may drop to MVFR
Monday night into Tuesday, especially across the north, but
range between VFR and MVFR downeast. Conditions should improve
to VFR Tuesday night into early Wednesday then drop back to MVFR
Wednesday night in lower clouds and showers.
near term: beach hazard remains in place through 00z(8pm) this
evening. Winds were 10 kts W/seas around 4 ft. Winds could pick
up a bit on Monday at 15 kts as a cold front apchs from the N.
Seas should hold around 4 ft away from the intra-coastal areas.
Short term: winds and seas are expected to be below Small Craft Advisory Monday
night through Thursday. Fog may limit visibility across the
waters at times.
ME...beach hazards statement until 8 PM EDT this evening for mez029-