Area Forecast Discussion
Issued by NWS Portland, ME

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739
FXUS61 KGYX 250225
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1025 PM EDT Fri May 24 2019

.SYNOPSIS...
High pressure will build in from the west tonight and will crest
over the region early Saturday before shifting offshore in the
afternoon. A warm front will push east through the region
Saturday night and will be quickly followed by a cold front on
Sunday. High pressure will build in from the northwest Sunday
night and Monday and will crest over the region Monday night.
High pressure will shift offshore on Tuesday as a warm front
approaches from the southwest. The warm front will slowly lift
north and east of the region Tuesday night through Wednesday. A
weak cold front will cross the region Wednesday night and early
Thursday.

&&

.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
1020 PM...Added overnight fog for inland valleys that will
radiate. Td depressions 2-5 F in a lot of these spots, with
further cooling expected. Otherwise forecast on track.

710 PM...made a few tweaks to cover a little quicker clearing
and winds diminishing a little faster, but overall forecast
remains unchanged.

Low pressure south of Nova Scotia will accelerate out to sea
this evening as high pressure builds in from the west. Looking
for gradual clearing from west to east this evening. Low
temperatures will range from the upper 30s to lower 40s north
and mid to upper 40s south.

&&

.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
High pressure will crest over the region early Saturday before
shifting offshore south of New England. After a mostly sunny
morning expect clouds to move in from the west ahead of an
approaching warm front. Will see a chance of showers getting
into the Connecticut Valley by early evening and rain will
quickly spread eastward Saturday evening.

Rain will quickly push east after midnight and should clear the
forecast area by daybreak. QPF rather modest with this system
with most areas only seeing a quarter to half inch. Lows
overnight will range through the 50s.

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
On Sunday a short wave trough will be approaching northern New
England from southern Canada. At the surface low pressure near
Hudson Bay will deepen and drag a cold front across the forecast
area late Saturday night into Sunday morning. This will spread
showers and thunderstorms across the forecast area, with
precipitation ending over the Midcoast during the late
morning/early afternoon. Upslope showers will continue in the
mountains through Monday night as the upper level wave passes
by.

High pressure builds in for Monday, with sunny to partly sunny
skies and highs in the mid 60s to mid 70s for the entire
region. On Monday night, radiational cooling conditions will be
strong, allowing low temperatures to drop into the mid to upper
30s north to upper 40s south. This dry weather will be short-
lived however as a warm front associated with low pressure
deepening over the Plains nears. Any showers should hold off
until Tuesday afternoon over NH before spreading east and north.
The European model is developing low pressure along Cape Cod
Tuesday night into Wednesday morning. If this occurs, additional
moisture would be lofted northward, with the potential for some
heavier showers along the coast. Regardless, we will be in the
crosshairs for low pressure lifting out of the Plains and over
the Great Lakes region on Wednesday, with a warm front
sharpening and focusing precipitation again over the northeast.

Climatologically, precipitable water values will be 1 to 2
standard deviations above normal Tuesday through Thursday. The
warm layer cloud depth increases to 3500 ft or higher by
Wednesday into Thursday morning. These two factors indicate the
enhanced likelihood of heavy rain. This looks especially true
Wednesday night into Thursday morning when QPF amounts will
approach 0.70 to 1.00 inches in a 12 hours period, which would
be enough to promote flooding on some area rivers and possibly
produce flash flooding over the higher terrain.

Scattered showers will continue Thursday with a cold frontal
passage finally occuring late, coincident with a deep upper low
dipping out of Canada. A secondary cold front will push through
Friday morning, and this will finally allow high pressure to
build back over northern New England and foster drier weather.

Isolated thunder is possible Wednesday, but thunderstorm chances
look especially good Thursday with MUCAPE values near 1000-1500
J/kg over southern and central NH and coastal ME.

&&

.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Short Term...VFR tonight through Saturday. MVFR/IFR ceilings
developing Saturday night.

Long Term...Expect showers early Sunday morning with widespread
MVFR to IFR conditions. This will improve by mid morning
Sunday, followed by another round of showers and thunderstorms
ahead of a cold front arriving from the northwest. Widespread
VFR conditions are expected Monday but MVFR showers return
Tuesday into Wednesday.

&&

.MARINE...
Short Term...Have extended SCAs through 00z for bays and outer
waters. SCAs may be needed again Saturday night.

Long Term...Southwest flow over the waters Sunday shifts to the
northwest behind a cold front Sunday night. High pressure moves
east across Quebec on Monday with winds turning southeasterly
by Tuesday afternoon as another weak wave pulls a warm front
northward. Borderline SCA conditions are likely Wednesday with
southerly winds increasing.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Beach Hazards Statement from 8 AM EDT Saturday through
     Saturday evening for MEZ023>028.
NH...Beach Hazards Statement from 8 AM EDT Saturday through
     Saturday evening for NHZ014.
MARINE...None.

&&

$$
SYNOPSIS...
NEAR TERM...Cempa/Sinsabaugh
SHORT TERM...Sinsabaugh
LONG TERM...Hanes
AVIATION...
MARINE...



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