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FXUS61 KGYX 232145

Area Forecast Discussion
National Weather Service Gray ME
545 PM EDT Tue May 23 2017

Weak high pressure will hold over the region through Wednesday as 
low pressure passes well offshore. A complex area of low pressure 
will approach from the southwest Wednesday night and Thursday and 
will slowly move northeast through southern New England and the Gulf 
of Maine Thursday night and Friday. High pressure will build in from 
the west Friday night and Saturday. A cold front will drop south 
through the region Saturday night and Sunday.


Have issued a quick update to account for current observational
trends and mesoscale models. CS shield continues over southern
areas, while skies remain mainly clear further inland. Expect
much of the CU fields to dissipate around sunset over the 

Prev Disc...
A stratus deck has moved offshore but it did take a
while for coastal locations to clear out today. After some 
clearing over the coastal plain and variable sun across the 
area, moderately dense cirrus blow off from the west has covered
southern NH and much of western Maine. Elsewhere cumulus had 
developed over the mountains. All this developed in WSW/weak 
ridging aloft and in advance of a warm front over the Great 
Lakes region. 

Expect more cloudy skies tonight with light and variable winds.
Overnight lows will range from the mid 40s to mid 50s.


Wednesday will be similar to today but with increasing moisture
due to an increased onshore flow. We'll see a weak sea breeze 
develop tomorrow afternoon with low pressure passing well south of 
the Gulf of Maine. That said there may be a stray shower associated 
with this low across southern NH or SW Maine. In addition, isolated 
mountain showers are possible as the elevated warm front nears 
tomorrow. Highs will generally be in the lower to mid 70s. Overnight 
lows will be a little warmer for northern zones in the upper 40s 
with lower 50s to the south.


A broad upper level ridge currently over the eastern portion of the 
US will shift eastward as the trough moves through the midwest and 
onto the east coast. This will set us up for an active pattern with 
a series of waves moving along the upper low and up the east coast. 

Thursday will start off partly sunny but quickly cloud over as 
low pressure develops to our south and moves up the east coast. 
This storm will deepen and pass across Cape Cod on Friday 
bringing widespread rain. While there is a fairly good consensus
there will be a coastal low, the strength of the storm is still 
seeing quite a bit of spread with QPF amounts as high as 2 
inches possible along the coast for the stronger solution and as
low as 0.5 inch. Have leaned a bit on the higher QPF both due 
to favoring the stronger solution and because of the long 
tropical fetch for the moisture source. 

The storm departs into the maritimes on Saturday with some
scattered upslope showers. Saturday afternoon and evening will
be a brief break from the rain. The next low will move through the 
Great Lakes on Sunday pushing a warm front and overunning 
precipitation through the area Sunday night. Another coastal low 
will spin up on Monday pushing another round of widespread 
precipitation through to start the week.


Short Term...VFR conditions will prevail with some possible
IFR/MVFR in low stratus and fog once again near RKD...AUG...and PWM 
late tonight into Wednesday morning. A low deck is lurking just 
offshore and should move back towards shore tonight. Additional fog 
or drizzle is possible late Wednesday night into Thursday morning.

Long Term... Thursday will begin with VFR and MVFR but rapidly drop 
to IFR on Thursday night as low pressure approaches the region. IFR 
with rain and fog will continue through the day on Friday with gusty 
winds along the coast. Conditions will improve to VFR with MVFR 
ceilings in the mountains for Saturday.


Short Term...Conditions should remain below SCA thresholds today
through early Thursday morning. 

Long Term...
A coastal low will cross the waters on Thursday into Friday with 
Small Craft Advisories likely and gale force winds possible ahead of 
the storm. Winds and seas will subside on Saturday and remain fairly 
calm through the start of next week.


In addition to the potential for a lot of rain on Friday morning, 
the easterly flow and winds associated with a coastal low will 
create a risk for coastal flooding. Onshore flow will develop 
Thursday ahead of the storm and strengthen through the day on 
Friday. This will result in a storm surge of around 0.5 ft Thursday 
night. The highest tides of the year will occur Friday, with the 
onshore component plus the storm surge resulting in coastal flooding.



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