Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
1027 am EDT Thursday Jul 28 2016
a weak cold front will briefly stall across the area today then
continue south to the coast tonight. The front will push offshore
Friday into Friday night as low pressure along the front tracks
south of the area.
Near term /through tonight/...
10 am update: the most sig chg this update was to move the
greatest tstm cvrg later during the mid to late aftn to correspond
to the tm of Max htg...which we believe will be alg an axis msly
S of a Caribou to nrn Somerset County line and northwest of the interior
downeast zones, based on where some initial shwr activity is
forming across north cntrl ptns of the forecast area. Kept enhanced tstm element
wording to include gusty winds, hail and hvy rnfl with likely pops.
Other chgs include adjusting fcst 6hrly qpfs closer to the Max
pop axis going into the aftn and eve and fcst hrly temps to aftn
Max temps based on latest sfc obs.
Prev disc: cold front is on our doorstep with isold showers
breaking out ahd of it. Tstorm is located north of the Vermont
border and will continue to approach County Warning Area this mrng. Expect as
front drops south, that showers and thunderstorms wl dvlp drg htg
with airmass destabilizing. Temps acrs the north wl rise into the
M/u 70s and downeast zones in the lwr 80s. This combined with
dwpts still in the 60s, wl result in convective available potential energy on the order of 1000
j/kg along the front. Wl retain gusty wind mention along with
locally hvy rainfall as pw values appch 1.75 inches drg the aftn,
mainly FM a Danforth-Dover line.
Front looks to mv as far south as downeast by midnight tonight bfr
stalling. Expect tstms to diminish twd midnight with a few showers
lingering along the bndry acrs the south. With srly flow advecting
in moisture and dwpts rmng in the 60s expect patchy fog to dvlp cwa-
wide once again tonight. Areas of fog can be expected ovr the waters
and potential exist for widespread fog to advect on the coast and
wl allow later shifts to expand this mention north. Northern
zones wl dip into the 50s in the wake of frontal passage with
downeast zones still experiencing 60s tonight.
Short term /Friday through Saturday/...
a weak cold front stalled along the coast early Friday will allow
for the chance of showers downeast as northern areas become partly
cloudy. A small low tracking east from southern New England will
then track along the southern edge of the Gulf of Maine late
Friday into Friday night. As the low approaches, there will
likely be a period of steadier stratiform rain over downeast
coastal areas with some showers or patchy rain further inland.
CAPES are progged to be near 750 j/kg downeast on Friday. Although
the precipitation may be stratiform, some lift from a weak upper
level shortwave carrying the low east may be just enough to spawn
some embedded convection so will include a slight chance for
thunderstorms downeast too. The low will exit east Friday night as
high pressure builds in from the west bringing clearing and
slightly cooler and drier air across the region. This will set the
stage for a mostly sunny, dry and comfortable day on Saturday as
the high pushes in.
Long term /Saturday night through Wednesday/...
high pressure across the area will bring a clear and pleasant night
Saturday night followed by sunshine again on Sunday. Sunday night
will likely remain mostly clear as high pressure stays over the
area. Our focus then turns to a weak wave of low pressure tracking
off the mid Atlantic coast. This system may brush the downeast coast
with some rain late Sunday night into Monday. The latest GFS
carries most of the moisture from this system south of our region
with the European model (ecmwf) bringing a better chance for some rain Sunday night
into Monday. Shallow shortwave ridging returns with dry weather
Tuesday into Wednesday as the low moves away. However, a back
door frontal boundary to our northeast may be close enough to
bring some thundershowers to northern areas Tuesday and again on
Wednesday. However, once the low moves away early next week,
downeast will be mostly sunny and dry into mid week.
Aviation /14z Thursday through Monday/...
near term: VFR at most terminals next 24 hours. Exception may be
bhb this morning with IFR vsbys forecast to develop in the next
svrl hours, continuing through 12z. MVFR restrictions expected in
fog after 00z tonight with potential for IFR/LIFR toward end of
taf valid time.
At bgr may see MVFR vsbys between 03z and 06z Fri in southerly
flow along stalled frontal boundary. Further to the north, expect
thunderstorms in the vicinity at any point after 18z this afternoon. Any terminal
experiencing -tsra will likely see lower restrictions and variable
Short term: VFR conditions are expected across the north on
Friday with IFR conditions in low clouds and some rain downeast.
Conditions should improve to VFR across the entire area Friday
night then be VFR Saturday into Sunday. VFR conditions are likely
Monday, except may lower to MVFR along the downeast coast on
Monday as another small low tracks offshore.
near term: winds and seas will remain below Small Craft Advisory through tonight.
Expect areas of fog to develop again after midnight over the
Short term: winds and seas are expected to remain below Small Craft Advisory
Friday through the weekend. Some fog may limit visibilities on the
water early Friday.