Intense Ocean Storm To Form South Of The Region

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FXUS61 KCAR 272208

AFDCAR

Area Forecast Discussion

National Weather Service Caribou ME

508 PM EST Wed Jan 27 2021

.SYNOPSIS...

Low pressure will track south of the region tonight into Friday,

with a trof extending back towards the coast. High pressure will

build toward the region Saturday, then cross the region Sunday.

Low pressure will begin to approach from the south later

Monday.

&&

.NEAR TERM /THROUGH THURSDAY/...

Weak mid level ridging will build across the region tonight. The

forecast soundings are indicating plenty of moisture below 700

MB, thus expect a continuation of mainly cloudy skies overnight.

There is some weak warm advection around 700 MB and this may

result in some light snow or light snow showers overnight, north

of the Katahdin region. Any precipitation that falls overnight

will be light, generally a couple hundreths of an inch or less,

thus any snow that falls will not accumulate much more than a

few tenths of an inch at best. A little concerned about the

potential for some light patchy freezing drizzle/light

snow/freezing drizzle combination late tonight, as forecast

soundings are showing dry air above 700 mb layer. Have decided

to mention patchy freezing drizzle after midnight, mainly north

of the Katahdin region. The cloud cover should keep temperatures

from falling much overnight, thus went a few degrees higher

than NBM numbers for overnight lows.

On Thursday, we will see the approach of a 500 MB low diving

southeast from Ontario/Quebec provinces. Again, expect a mainly

cloudy sky with plenty of moisture in the low levels. Continued weak

warm advection around 700 MB will likely generate a little light

snow or snow showers, mainly north of the Katahdin region. As

we head later into the afternoon, the chances for snow will

increase farther to the south in association with the developing

inverted trof. Again, any snow on Thursday will remain

relatively light, generally an inch or less. Highs on Thursday

will range from the mid to upper 20s north and low to mid 30s

Downeast.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...

Surface low pressure will track well southeast of the Gulf of

Maine Thursday night into Friday, with a trof extending back

across the Gulf of Maine toward the Downeast coast. However,

uncertainty still exists regarding the exact location and

movement of the trof. At the same time, an upper level low

will move south across New England. Convergence along the trof

will help focus an area of snow Thursday night into Friday.

Whether this area of snow remains mostly offshore, or reaches

the Downeast coast is still uncertain. Accumulating snow is

likely Downeast Thursday night into Friday. However,

accumulations will be dependent on the eventual location,

persistence and movement of the trof. Lesser snow chances will

exist across northern portions of the forecast area. The trof

will pivot southwest then south later Friday into Friday night

with snow exiting across the Gulf of Maine. Could still have

lingering snow showers Downeast early Friday night. Otherwise,

expect mostly/partly cloudy skies across the region Friday

night. High pressure will build toward New England Saturday

with partly cloudy skies across the forecast area. Temperatures

will be at slightly below normal levels Friday/Saturday.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...

High pressure builds toward the region Saturday night, then

crosses the region Sunday through early Monday. Generally

expect mostly clear/partly cloudy skies across the region

Saturday night through early Monday. Low pressure will intensify

along the Mid Atlantic coast Monday into Monday night then

track northeast Tuesday into Wednesday. Uncertainty still exists

regarding the track and timing of this low which has the

potential of bringing accumulating snow to the region. However,

potential impacts from the storm will be dependent on the

eventual track and timing of the low. Temperatures will be at

slightly above normal levels Sunday, with above normal level

temperatures expected Monday through Wednesday.....