Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Caribou ME
1217 am EDT sun Aug 2 2015
a series of upper level disturbances will move across the region
through the weekend bringing showers and thunderstorms. A cold
front is expected to approach the region Monday night and move
across the area on Tuesday.
Near term /through today/...
no changes to going forecast overnight.
The upper level disturbance which helped support the severe
thunderstorms this afternoon is now exiting across the Maritimes.
Surface high pressure will build across the region overnight with
partly cloudy skies across northern areas and mostly clear skies
across the remainder of the forecast area. Overnight low
temperatures will range from the middle to upper 50s north...to the
upper 50s to around 60 downeast. Have updated the forecast to
adjust for current conditions along with expected overnight
temperatures and cloud cover. Have also included patchy fog
for tomorrow...another upper shortwave will trek across the
region. This will bring scattered showers and thunderstorms,
mainly to northern portions of our area. Highs will be in the middle
70s north, to around 80 across interior downeast.
Short term /tonight through Tuesday/...
County Warning Area will be in transition from hipres to appchg lopres on Sun night.
Lopres will mv into eastern Quebec with trailing cold front back to the west by
12z Monday. 12z models differ on placement of front by this time with
GFS further west than NAM/CMC. 500 mb flow becomes zonal at the start of
the short term with brief ridging through most of the overnight. Ridge will
deflect S/waves off to the northwest with only isolated rain showers or thunder expected
across the far north toward daybreak as upper trough and associated front approaches.
Min temperatures Sun night will be fairly uniform across County Warning Area in the u50s. Srly
flow across downeast will keep temperatures warm and cloudy skies across the northwest will
keep temperatures from dropping off too much drg the night. Elevated
instability expected to be present through 04z across The Crown of Maine.
Airmass will likely destabilize ahead of next appchg front on Monday.
Temperatures will warm into the l/M 80s as temperatures soar above 20c. BUFKIT soundings
indicate 500-1000 j/kg per GFS for Monday afternoon while NAM is about 2x
as high. Cyclonically-curved hodograph along with strong bulk
shear values and strong middle-level lapse rates will likely spell the next
severe threat late afternoon into the evening.
Frontal passage occurs sometime Tuesday morning with continued showers and possibly
thunderstorms ahead of upper level trough. Maxes on Tuesday will be right around normal
as showers and clouds prevent much rise in temperatures.
Long term /Tuesday night through Sunday/...
the main concern for the extended forecast period is a series of
weak upper level shortwaves that are prognosticated to propagate eastward
across Maine. Each wave could produce isolated/scattered showers and
storms across the northern two thirds of our County Warning Area...with the best
chance occurring on Wednesday. This activity will have a strong
diurnal component...so we are expecting most of the precipitation to fall
during the daytime hours. Temperatures will be cooler with below
normal temperatures. Highs will generally range from the upper 60s to middle
Aviation /04z Sunday through Thursday/...
near term: variable conditions will occur with any patchy fog
overnight. Otherwise...VFR conditions are expected overnight. VFR
will prevail until 18z Sunday, then local MVFR is possible at the
northern terminals as scattered showers and thunderstorms develop
during the afternoon.
Short term: VFR expected through Monday morning before line of
showers and thunderstorms ahead of front brings MVFR and possibly
IFR conditions to terminals late Monday afternoon continuing through
the day on Tuesday. VFR and occasional MVFR can be expected
through the middle of the week as upper level disturbance moves
through then VFR after.
near term: winds/seas will remain below Small Craft Advisory
levels overnight through Sunday.
Short term: winds/seas will remain below Small Craft Advisory
criteria through Monday night. Southerly winds ahead of front may
allow seas to build above 5 feet on Tuesday.