Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Gray ME
655 PM EDT Thursday Mar 26 2015
low pressure will move across southern New England this evening.
High pressure will then gradually build into the region Friday
through Sunday. Low pressure will move eastward across Quebec on
Monday and will drag a cold front across our region Monday night.
Quick moving low pressure crosses the area Tuesday night into
Wednesday and again on Thursday.
Near term /until 6 am Friday morning/...
dense fog has become widespread across much of southern Maine and
southern New Hampshire. Have issued a dense fog advisory until 11
PM. Northerly winds should advect slightly drier air into the
region and mix out some of the fog at that time.
Areas of rain and rain showers continue to move rapidly to the
northeast in a strong gradient flow aloft. The changeover to snow
will continue this evening across the higher terrain of the
northern mountains. Snow will mix in over central areas as well by
around 08z...but this is mainly an elevation based snow event.
Previous disc...a positive tilted and progressive long wave trough
will move across New England tonight. Ahead of it warm air at all
levels spread across the region during the afternoon. A weak wave
will develop along the base of this trough and move across
southern New England tonight. To the north of this wave overunning
rain is expected across the region with snow over the higher
elevations. Quantitative precipitation forecast amounts will range from .50-.75 inches which
should not pose any flooding problems. Overnight cold air
advection gradually spreads south allowing the rain to change to
snow in the lower elevations in the mountains and foothills with
some light accumulations expected by morning. Over southern areas
the precipitation will probably end before enough cold air spreads
south to cause any changeover. Used a blend of the models for quantitative precipitation forecast
and overnight lows.
Short term /6 am Friday morning through Friday night/...
Friday and Friday night the base of the upper trough slowly
progresses east but will have plenty of cloud cover lingering
across the area. Some partial clearing may occur over northern
areas while southern areas remain mostly cloudy. Temperatures will
be near seasonal on Friday and Friday night as a blend of the
model guidance suggests.
Long term /Saturday through Thursday/...
the bulk of the precipitation associated with a deepening low
pressure wave along the offshore front will remain in the Gulf
of Maine on Saturday... however coastal sections of New Hampshire and Maine
will have a slight chance of showers through the day. Skies will
be cloudy contributing to a small diurnal rise into the middle 30s
over the coastal plain. Farther north middle to upper 20s for highs
is more likely.
Skies begin to clear out north to south overnight and colder air
filters in making for a chilly night. Sprawling high pressure
covering most of the nation moves into the southeastern states
bringing a northerly and then eventually westerly wind gradient
to New England. Surface temperatures for much of the area respond
to this downsloping component as well as synoptic scale warming
result in a warming trend Sunday.
The next chance of precipitation arrives Monday as warm air
advection ramps up ahead of a deepening surface cyclone well to
our north. The little bit of cold air associated with this system
should mostly dam north of the mountains and moderate within 12-18
hours. Over the coastal plain we will continue to see readings
reach the 40s in the afternoon with the occasional 50 degree
reading Tuesday and Wednesday. A weak wave transports quick moving
low pressure across the area Tuesday night into Wednesday before
moving it out to sea. This will bring chance precipitation to the
region... at this time it looks like it would bring mixed ptype.
Lastly models follow this with a stronger system for Easter
weekend which may cause have travel implications.
Aviation /00z Friday through Tuesday/...
short term...IFR conditions are expected later this afternoon and
tonight in rain...with snow at higher elevations across northern
New Hampshire and the western ME mountains. VFR conditions will gradually
return on Friday and continue Friday night.
Long term...scattered MVFR conditions possible in mountain and
coastal snow showers Saturday. Scattered MVFR conditions possible
Monday in rain and snow showers as a cold front crosses from north
a Small Craft Advisory will be required over the outer waters due to expected
building seas later this evening and continuing through Friday.
Winds will remain well below Small Craft Advisory criteria through Friday night.
Long term...waves remain high on Saturday before dropping by
Sunday morning. Seas and winds increase briefly Monday morning to
Small Craft Advisory criteria ahead of a cold frontal passage.
warmer weather and one half to three quarters of an inch of rain
will induce some runoff this evening. We will likely see some
rises on southern rivers. At the current time we do not expect any
big issues. Perhaps some minor poor drainage flooding this
evening. However...will have to monitor for ice movement on
rivers and streams.
ME...dense fog advisory until 11 PM EDT this evening for mez018>028.
New Hampshire...dense fog advisory until 11 PM EDT this evening for nhz005-
Marine...Small Craft Advisory for hazardous seas from 11 PM this
evening to 6 PM EDT Friday for anz150-152-154.