Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
1206 am EDT Monday Apr 27 2015
upper level low pressure will keep unsettled conditions across
the region through the early next. A brief break in the unsettled
weather is expected by the middle of the week.
Near term /through today/...
update 0000 edt: have adjusted temperature and dew point base on
latest observations. No other changes.
A persistent upper low will continue to spin over the Canadian
Maritimes tonight into tomorrow. A shortwave will rotate around
the back of this low, dragging its associated surface low
southwestward from the Maritimes tonight to the Gulf of Maine by
Monday afternoon. The shortwave feature is already evident on
satellite imagery this afternoon as a band of higher cloud tops
and deeper moisture spinning westward through New Brunswick. This
activity will slide into The Crown of Maine overnight, and then
continue to push southward across the state tomorrow. Some snow
could mix in with the rain overnight, mainly in the higher terrain
of the north Maine Woods. Otherwise, temperatures in the upper 30s
will keep the precipitation in the form of rain.
Showers will continue through tomorrow morning and then will
gradually wind down from north to south during the afternoon. Winds
will increase out of the north as the pressure gradient tightens in
response to the aforementioned surface low crossing Nova Scotia to
the Gulf of Maine. Highs will be similar to what we've seen today,
mainly in the upper 40s to lower 50s. Total rainfall for tonight and
tomorrow will be a quarter inch or less.
Short term /tonight through Wednesday/...
whats left of spokes of shortwave energy moving west to east into our area around
an quasi-stationary upper low near Nova Scotia will still keep
mcldy...unsettled and fairly raw conditions over the forecast area...with
a sig amount of shower activity being driven by diurnal heating...
meaning the best chance of showers will be Monday evening and again Tuesday afternoon
and evening. A little more improvement on Wednesday...with the operative
word being little...with widely scattered to scattered showers still possible
Wednesday afternoon over NE and east central portions of the forecast area. Quantitative precipitation forecast with showers will
be fairly lclzd...and generally less than a tenth of an inch
cumulative through Wednesday for most lctns. Temperatures will be msly held
below average during daylight hours due to cloud cover and any showers.
Long term /Wednesday night through Sunday/...
longer range models are in relative agreement with slowly
improving conditions for the forecast area Wednesday night and Thursday as the upper low
moves further east into the open Atlantic a narrow upper ridge/col zone
of very weak flow aloft moves over the forecast area.
Aftwrds...longer range models are in relatively poor agreement for
Friday and Sat regarding the potential of shortwave energy from central can
phasing with southern jet stream shortwave energy moving east-northeast from the lower MS
River Valley. The dtmnstc 12z GFS is much stronger with shortwave energy
digging ssewrd from central can...resulting in a stronger...more
amplified upper low and much stronger...further north surface low into the
southern Gulf of ME. The 12z European model (ecmwf) is much weaker with shortwave energy from
central can...resulting in both the surface and upper low being
weaker...moving more ewrd off the southeast U.S. Coast. The superblend does
introduce low chance rn probability of precipitation for Friday and Friday night to southern portions of the
forecast area...but confidence is low. In fact...CPC outlooks suggest this to
be the beginning of a fairly dry period for our forecast area...and wpc medium range
guidance favors more toward the European model (ecmwf) solution. With this in
mind...we begin to go with a slow warming trend this late week
and weekend...with potentially more sig warming Erly next week after
the uncertainty period with regard to the upper low late this
Aviation /04z Monday through Friday/...
near term: MVFR/VFR ceilings will lower from north to south
overnight as a band of rain showers spreads across the state.
Prevailing IFR is likely at kfve, kcar, and khul by 06z, with
ceilings wavering right around 1000 feet at the other sites.
Ceilings will improve gradually through the day Monday, with
prevailing MVFR everywhere by 14z.
Short term: VFR...xcpt MVFR clgs and occasionally visibilities with any showers...
especially northern taf sites Tuesday through Tuesday evening.
near term: no headlines will be needed on the waters tonight or
Monday. Winds and waves will both remain below small craft criteria
during this time.
Short to long term: Small Craft Advisory wind and marginal seas are likely later
Monday night into Tuesday...then no hdlns expeceted Tuesday night through Thursday night. Kept
close to ww3...xcpt for Friday-Sat tm frame...where we lowered WV heights
in conjunction with neighboring offices...factoring a weaker and
further S European model (ecmwf) storm solution in this tm frame.