NWS Caribou, Maine Area Forecast Discussion

FXUS61 KCAR 291402

Area Forecast Discussion
National Weather Service Caribou ME
1002 AM EDT Thu Jul 29 2021

High pressure will move east of the area today as low pressure
approaches from the west. Low pressure will cross the area
tonight into Friday as it pulls a cold front through. High
pressure will build south of the area Saturday. Low pressure
will approach on Sunday.


1000 AM Update...Mostly sunny skies this morning giving temps a
boost early on. Lower clouds w/ greater moisture are becoming
more widespread south of Maine. These will work in later this
afternoon. Until then, will likely see plumes of cirrus overhead
through the morning, with diurnal cumulus dotting the mid
levels. Did push arrival of rain showers back to the evening;
guidance soundings slowly saturate top down west to east.

Previous Discussion...
Today will begin clear and chilly with some patchy fog over the
rivers and lakes. High pressure will then bring a mostly sunny
morning followed by some increasing clouds this afternoon as low
pressure approaches from the west. Some light rain may begin to
stray into western areas at the end of the day. A trough of low
pressure will move in tonight spreading rain into western areas
early in the evening and further north and east late in the
evening. A rumble of thunder can`t be ruled out over some south
central areas overnight. Otherwise, this is expected to be a
stratiform overrunning rain event. The surface trough will
initially be an open wave with generally light rain pushing
across the area overnight. Low pressure will begin to get
better organized along the coast early Friday morning as jet
energy rounding the bottom of the trough streams into western
and southern New England. This may begin to make rain a little
steadier and heavier initially in southern areas very late
tonight into early Friday morning.


Rain wl be ongoing Fri morning but what area wl see the heaviest by
12z rmns to be seen. 00z guidance left a lot to be desired with
regard to initialization thanks to the MCS over the upr midwest
tonight. Am not thoroughly convinced that coastal low wl be able to
dvlp over the Gulf of Maine Fri morning as models continue to flip-
flop with well-defined sfc low over swrn GOM by 12z Friday per
latest NAM/EC with a weaker low in the vicinity per GFS/CMC.
Eventual movement of MCV tda wl determine whether potential for hvy
rain sets up for portions of our FA Fri morning.

Upr lvl trof appears to begin going negative Fri morning with
potential for locally hvy rain over sern areas Fri morning bfr main
crux of qpf exits northeast into NB. Best location for locally hvy
rain looks to be over Washington County in area of coupled jets and
if any elevated storms can develop. 0.50-0.75 inches in a 6 hour
period, more on the order of 3-4 hrs are possible over this region.
This is the area that needs the rainfall less than any other portion
of the CWA. Storm total rainfall looks to be between 1-1.25 inches
to the south of the I-95 corridor with 0.50-1.00 inches expected

As system exits into the Maritimes over the weekend expect that we
wl see showers in nwrly flow as weak disturbances move acrs the
region thru Saturday. Area wl experience blo normal temps with highs
over the north likely to remain in the 60s and lows in the
40s through the end of the pd.


A brief break in the wx is expected Sun morning ahead of the next
system mvg in fm the west as upr lvl troffing continues. Question
centers around how widespread rain wl be drg the day Sunday as
majority of guidance indicating Downeast areas wl be most likely to
see rainfall Sun aftn and thru the overnight. GFS meanwhile has most
potent s/wv tracking thru nrn areas Sun night which warrants keeping
likely pops over entire region Sun night. Wl fine-tune chcs and area
as we get closer in time.

After a brief break Mon night into Tuesday pattern becomes a little
harder to discern when next significant rainfall moves into the
area. Subtropical ridge shows signs of strengthening by the middle
part of the week with moderating temps expected on Wed.


VFR conditions are expected today into this evening. Conditions
will likely lower to MVFR then IFR late tonight as lower clouds
and rain move in.

Fri-Fri night...IFR/LIFR Fri in heavy rain and embedded tstms on
Fri. Improvement to MVFR/VFR possible at BGR and BHB in the
evening with northern terminals still seeing IFR restrictions. S
winds becoming NW 5-15kts Fri afternoon and gusty into Fri

Sat-Sat night...Mainly VFR, though possible MVFR across the
north in showers Sat aftn. W 5-10kts and gusty Sat afternoon.

Sun-Mon...MVFR, possible IFR/LIFR in rain. SW 5-10 kts Sun,
light S overnight then W Mon.


Wind and seas should remain below SCA today. Winds will reach
SCA in gusts to 25-30 kt overnight in the south wind ahead of
the approaching trough of low pressure. Visibilities should be
good through this evening but will likely lower in some rain
and patchy fog late tonight.

SHORT TERM: SCA possible late Fri night into Sat morning with
wind gust marginal around 25kts. Seas increase to 5 kts on the
outer waters Sat morning. Rain and possible embedded thunder Fri
morning with visibilities reduced in patchy fog. Remainder of
the weekend into early next week will be below SCA levels.


MARINE...Small Craft Advisory from 9 PM this evening to 8 AM EDT Friday
     for ANZ050>052.



Near Term...Bloomer/Cornwell
Short Term...Farrar
Long Term...Farrar

NWS CAR Office Area Forecast Discussion