518
FXUS61 KGYX 121405
AFDGYX

Area Forecast Discussion
National Weather Service Gray ME
1005 AM EDT Wed Mar 12 2025

.SYNOPSIS...
High pressure builds in this afternoon. A weak system will
cross southern New England tonight into Thursday bringing clouds
and slight chances for snow showers. High pressure then returns
for the end of the week with temperatures rising above normal
Friday and Saturday. A frontal system approaches late in the
weekend bringing chances for widespread rain and posing an
elevated risk for ice jam flooding.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

1000 AM...Satellite imagery currently shows a band of clouds
over the Gulf of Maine. These clouds are associated with a cold
front that just passed the region. With the cold front passed,
high pressure has arrived into the region with a tranquil
remainder of the day expected. In addition, a weak upper-level
disturbance over the Great Lakes will bring some cloudier skies
eastward. These clouds should arrive in northern New England by
the end of the day. Otherwise, minimal changes were made to the
ongoing forecast, refreshed daytime temperatures to reflect
observational trends.


635 AM...Minor update to reflect observational trends
in temperatures and dewpoints.

Previously...

Northwest winds are picking up across the area early this
morning in the wake of a cold front pushing offshore. Winds will
gradually ease into this afternoon as high pressure builds over
the region. Highs will range from the 20s across the north to
the 40s across the south with partly cloudy skies. Clouds will
increase later this afternoon from west to east as a weak system
approaches from the west.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH 6 PM THURSDAY/...
Skies will become mostly cloudy tonight as a weak system crosses
southern New England. Latest NWP guidance suggest moisture will
be limited with only slight chances for snow showers across NH
and far SW Maine with little to no accumulation.

High pressure will remain centered east of the area through
Thursday for mostly dry conditions. Onshore winds will lead to
mostly cloudy skies along and south of the mountains with highs
across the area in the upper 30s to low 40s.

&&

.LONG TERM /THURSDAY NIGHT THROUGH TUESDAY/...
04Z Long Term Update... Little change in the extended forecast.
Moderating temperatures will be the main theme with our best
chance for widespread rainfall arriving late Sunday through
early Monday.

Previously...
Pattern Overview: The second half of the week looks quiet as a
broad 500mb trough exits the region on Thursday and flow becomes
more zonal. A significant closed low develops in the Central
CONUS, but becomes more of an open wave as it reaches our area
at the end of the week. This will be part of the forcing for
rainfall on Sunday into Monday.

Impacts and Key Messages:
* An elevated risk for ice jam flooding exists on Sunday and
  Monday as a warm system will bring rain and rapid snowmelt to
  the region, contributing to river rises which will break up
  and move river ice. Further details can be found in the
  dedicated hydrology section below.

Details: Thursday night: Moist return flow keeps skies cloudy
with fog possible along the coastal plain. Skies stay mostly
cloudy overnight so temperatures only bottom out in the 20s
areawide with onshore flow keeping the immediate coast even a
little warmer.

Friday and Saturday: Skies look to trend toward partly cloudy
on Friday as high pressure noses in one more time before sliding
off to the east. Forecast soundings continue to show good
mixing up to 925mb where temperatures will be approaching +3-5C.
This supports high temperatures in the mid 40s to lower 50s.
Fog and low clouds are possible again Friday night as moisture
continues to stream into the region, so low temperatures Friday
night look to bottom out in the low to mid 30s. Rinse and repeat
for Saturday, but with 925mb temps more in the +6-8C range
amounting to highs in 50s across the board. The only caveat
being that the seabreeze may cause the immediate coast to fall
short of that, remaining in the mid to upper 40s. Clouds and the
chance for light rain showers increase Saturday night as a warm
front associated with the next system approaches. This will
hold low temperatures in the upper 30s to mid 40s.

Sunday-Tuesday: This is the period to watch as global models
are in good agreement of a widespread rain event Sunday into
Monday. The biggest question mark at the moment is QPF, which
is pretty good for a day 6/7 system. Generally, it looks as
though Sunday features light but steady rain showers as the warm
front crosses the region first. The cold front crosses the
region Sunday which brings about the window for heavier rain and
gusty winds. Trends have been holding steady with ensemble
means for total QPF still in the 0.50" to 0.75" range with
locally higher amounts around an inch in the mountains. We get
so warm during the day sunday that even after the cold front
crosses temperatures remain above freezing so any showers still
lingering remain rain during the day Monday. Anything that
lingers into Monday night has a chance of turning wintry with
the passing of a secondary cold front, but at that point it
would be very light. What is already certain with this system is
that temperatures and dewpoints during this time leads to rapid
snowmelt. This combined with the rainfall will lead to river
rises which will break up and move river ice, potentially
causing ice jams that could lead to flooding. More details on
this risk can be found in the hydrology section below.

&&

.AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Mainly VFR today. Skies turn overcast tonight with
cigs approaching MVFR thresholds across southern NH after 06Z.
MVFR cigs may linger along the coastal plain through Thursday
morning and will lift going into Thursday afternoon.

Long Term...Ceilings and visibilities will be variable across
the area Thursday night through the day Saturday as increasing
moisture may lead to the development of low clouds and fog
mainly during the night and early morning. Overnight Saturday
ceilings will lower as warm front approaches. Rain and low
ceilings will persist through Sunday with periods of IFR
visibilities possible in heavier rain Sunday night. Wind gusts
remain light through Saturday before picking up to 25-30kts on
Sunday with the passing of a cold front.

&&

.MARINE...
Short Term...Winds relax going into the afternoon as high
pressure builds over northern New England. Winds shift out of
the east southeast tonight and Thursday as high pressure moves
east of the waters.

Long Term...Wind gusts and seas remain below SCA criteria
through the day Saturday as high pressure slides over the
waters. Wind gusts ramp up overnight Saturday as a series of
fronts crosses the waters with a period of southerly gales
possible late in the day Sunday as a cold front crosses the
waters. Seas also peak overnight sunday reaching 8-10ft.

&&

.HYDROLOGY...
A controlled melt is likely this week as temperatures warm into
the 50s for much of the region, with runoff slowing at night as
temps fall below freezing. The slow release of the snowmelt
will keep river rises limited. River ice will likewise undergo
weakening through thermal rot, particularly in southern streams.
Attention turns to a dynamic storm system this weekend that
will spread rainfall over the region, resulting in more rapid
snowmelt late Sunday into Sunday night. There remains much
uncertainty in rainfall totals with the potential for over an
inch particularly in the south facing slopes of the White
Mountains. With gusty S winds and high dewpoints around 50 the
melt rate will accelerate over a ripened snowpack, with snowmelt
loss of 1-2" runoff possible. The combination of rain, snowmelt
and weakened river ice due to thermal rot, will cause river
rises sufficient to break-up and move river ice, leading to an
elevated risk for ice jam flooding by Monday.

&&

.EQUIPMENT...
KGYX radar is down and is awaiting parts for repair.

&&

.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 11 AM EDT this morning for
     ANZ150>154.

&&

$$

NEAR TERM...Palmer/Schroeter
SHORT TERM...Schroeter
LONG TERM...Baron/Tubbs