Area Forecast Discussion
Issued by NWS Caribou, ME

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FXUS61 KCAR 251729 AAD
AFDCAR

Area Forecast Discussion...UPDATED
National Weather Service Caribou ME
Issued by National Weather Service GRAY ME
129 PM EDT Thu May 25 2017

.SYNOPSIS...
High pressure will remain to our northeast early today. Low
pressure will approach from the southwest this afternoon into
tonight then track across the Gulf of Maine on Friday.

&&

.NEAR TERM /THROUGH TONIGHT/...
1130 AM Update...Forecast continues to be in good shape with
only minor updates...first to slow PoPs arriving from the
south...but at the same time increase cloud cover. Temps remain
on track.

9 AM Update...Primary change this hour is to lower temperatures
just a tad based on morning observational trends. Gradually
increasing high cloudiness attm is covered well in inherited
forecast. Can/t rule out a stray shower this afternoon...but all
in all a dry day with seasonal temperatures expected.

6 AM Update...Increased cloud cover just a bit Downeast where
high clouds have spread across. Also, some minor adjustments to
temps. Otherwise, no major changes this hour.

High pressure over the Maritimes will remain in control of our
weather today. The day will begin partly cloudy, then clouds
will increase from the southwest this afternoon as moisture
begins moving in from a trough of low pressure approaching from
the southwest. Some light rain may begin to move into Downeast
areas this afternoon into this evening as an initial surface
wave of low pressure slides to our south and a band of moisture
lifts up from the southwest. A stronger, more organized low will
then lift north from the trough later tonight pushing a more
substantial area of rain north into the area late tonight. By
early Friday morning rain should cover central and Downeast
areas with some light rain possibly pushing into the north. An
increasing northeast wind will accompany the system as surface
low pressure lifts into the Gulf of Maine.

&&

.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
There are still some differences among the model guidance w/the
latest low pres system which leads into the placement of
rainfall.

Low pres is expected to track across the Gulf of Maine on Friday
w/rain being brought all the way into northern areas. The latest
run of the ECWMF and Canadian Global are heavier w/the rainfall
and bring more rain further n and w. The GFS and especially the
NAM keep the far n and nw areas at 0.10 inches or less. This
includes the St. John Valley and the Allagash. The upper low is
forecast to remain across the Gulf of Maine w/the best forcing
residing across the central and downeast areas. The GFS mid
level forcing matches well w/this setup. The NAM is similar to
this alignment as well. Thinking here is that the ECMWF and
Canadian Global could be too heavy w/their rainfall and too far
west given the upper low is further s and fills w/time as the
system weakens pulling away. Confidence attm is not high enough
to alter the daycrew`s assessment w/the rainfall across central
and downeast areas. Therefore, decided to stay w/consistency on
the forecast. This means rainfall amounts will vary from north
to south w/0.10-0.25 inches for Northern Maine say from
Caribou- Presque Isle n and w. From Houlton and Millinocket down
through central and downeast areas, rainfall amounts will be
0.50-1.00 inch. Central and downeast areas could see heavier
amounts as strong llvl convergence is noted by the NAM and even
the GFS through early afternoon in these areas. Temperatures
will vary as well w/nw areas including the St. John Valley
seeing upper 50s to around 60 w/less rainfall expected while the
rest of the CWA sees low to mid 50s.

The rain is expected to quickly end by Friday evening and the
low continues to pull away. The airmass looks like it will dry
out especially above 850 mbs. Below that level, moisture looks
like it will hang in w/a nne wind setting up. This is shown by
the latest NAM and GFS soundings showing deep moisture holding
below 850mbs. Therefore, low clouds expected which will keep
temps up overnight. Drier for Saturday w/daytime temps
rebounding back into the 60s. Some high clouds are expected to
move in across the region as an upper disturbance moves across
the region.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
Unsettled weather looks like it will set up later Sunday and
could very well continue into Memorial Day and beyond.

Sunday was looking to be dry and pleasant day but the latest
runs of the GFS and ECWMF want to lift a warm front across the
northern tier of the CWA by Sunday afternoon. This would mean
the possibility of showers and perhaps a thunderstorm as some
instability does look to be there. The Canadian Global is drier
and shows the high to the ne holding in. Attm, confidence is low
on this setup and decided on 20-30% pops across the Crown and
nw areas and kept the rest of the CWA dry. Looking for upper
60s to around 70 w/the exception of the coast as temps could be
colder due to a s wind off the cold Gulf of Maine waters.

Unsettled pattern looks to be setting up from Memorial Day into
Wednesday. A large low pres system is forecast to move slowly e
from central Canada w/a series of disturbances moving across
the New England region. These disturbances will bring showers to
the region w/the most concentrated rainfall coming Tuesday into
early Wednesday. Daytime temperatures look to be below normal
during this stretch w/the aforementioned pattern setting up.

&&

.AVIATION /18Z THURSDAY THROUGH MONDAY/...
NEAR TERM: Clouds will thicken and lower tonight ahead of low
pressure moving northeast into the Gulf of Maine. VFR all sites
attm will lower to MVFR/IFR towards daybreak from BGR south.
Easterly winds strengthen to 12g22kts overnight.

SHORT TERM: Rain continues to spread north with IFR/LIFR
restrictions in moderate to potentially heavy rain from CAR/PQI
south...with precipitation reaching FVE around 15Z on Friday.
Rain continues through Friday evening before tapering to showers
Friday evening with IFR/MVFR restrictions gradually improving
to VFR Saturday morning and continuing through Sunday. Another
frontal system arrives from the west on Monday with MVFR
restrictions likely.

&&

.MARINE...
NEAR TERM: A SCA will stay for later today into tonight for
northeast winds gusting up to 30 kt. High astronomical tides
will result in strong tidal currents tonight through the
Memorial Day weekend. This will be addressed in the Hazardous
Weather Outlook.

SHORT TERM: Still looking at SCA conditions for winds and seas
into Friday afternoon. Winds will start to relax as the low
pulls away but seas will stay up longer to around 6 ft or so due
to sse swell component. Seas will drop off by midday Saturday
as winds become light and seas subside below 5 ft. These
conditions will continue into Sunday as high pres builds across
the region.

&&

.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...Small Craft Advisory until 8 PM EDT Friday for ANZ050>052.

&&

$$



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