Scientific Forecaster Discussion
fxus61 kaly 271036
Area forecast discussion
National Weather Service Albany New York
636 am EDT Mon Mar 27 2017
a warm front moving through the region will bring a
period of rain today, mainly for this morning. A few pockets of
freezing rain are possible early, especially over western New
England. Milder temperatures are expected for later today into
tomorrow before a cold front crosses the region by tomorrow
afternoon or evening with some additional rain showers. Cooler, but
dry weather will return for the middle of the week before another
storm system impacts the area for Friday into Saturday.
Near term /until 6 PM this evening/...
as of 635 am EDT...a stationary front is located well south of
the region over the mid-Atlantic states, but this front will
start to lift northward this morning as a warm front.
Based on sfc obs from ASOS sites and the New York state mesonet, temperatures
have been stuck in the lower to middle 30s over the past 12-18
hours, but are finally starting to rise somewhat thanks to
south to southeast winds at low levels. Some sheltered valley
areas (mainly across western new england) continue to see very
light or calm winds and as a result, are still stuck below
freezing. These temperatures have been slow to rise, but should
finally reach above freezing by the mid to late morning hours.
As the warm front heads towards the area, isentropic lift/warm
air advection will allow for a period of steady rainfall this
morning. This rainfall is already spreading across western areas
and will continue to expand in coverage and intensity over the
next few hours. Although this precip will just come in the form
as a cold rain for the bulk of the area, any areas that are
below freezing at the surface may see a brief period of
freezing rain, such as across the southern Adirondacks, eastern
Catskills and across western New England. The best chance of
this occurring will be across southern Vermont and the Berkshires and
a west-southwest (freezing rain advisory) continues until noon for all our
western New England zones to account for this possibility. Most
of the icing will be light, generally a tenth of an inch or
less, although some parts of southeastern Vermont to the east of the
Green Mountains may wind up seeing close to a quarter inch. Any
amounts of ice will be enough to make any untreated surfaces
By the afternoon, the steady rainfall will be tapering off to
areas of showers, but plenty of clouds and drizzle will
continue. Cannot totally rule out some additional rainfall this
afternoon, but it looks fairly spotty. Temps should continue to
warm into the mid 40s to low 50s across the area.
Short term /6 PM this evening through Tuesday night/...
as the warm front lifts north of the area, the best forcing will
shift away from the area for the overnight hours. As a result,
additional precip will be limited overnight, but it will
continue to remain cloudy, foggy and damp due to abundant low
level moisture. Temps will only slightly drop, as the region
will be in the warm sector and clouds will limit the amount of
cooling overnight, with lows falling into the upper 30s to lower
On Tuesday, the storm's cold front will be heading towards the
area from the west. There will be wave of low pressure
developing along the boundary, but latest model guidance appears
to show this wave just missing our area to the south. Still,
some additional showers are possible with the front nearby and
as it passes, especially for the afternoon and evening hours, so
pops will be in the high chc or likely for most areas by late in
Model soundings and ensemble guidance suggest precipitable water values rise
to around 1.00 inch, which is 1-2 Standard above normal for late
March. This could allow for some moderate bursts of rain with
the frontal passage. Also, according to the latest nam12, the
best elevated instability (showalter values less than zero)
appears to just miss our area to the south over the mid-
Atlantic states and based off the latest guidance from spc, will
not include any thunder in our area. Still, will monitor model
trends in case instability gets any further north, allowing for
a few rumbles of thunder along with the frontal passage.
Despite the clouds and showers, it looks mild once again for
Tuesday with temperatures reaching into the 50s across the bulk
of the area.
Showers should quickly taper off with the passage of the cold
front on Tuesday evening, allowing for some clearing on Tuesday
night. Temps look to fall in the 30s, although the only areas to
fall below freezing will be across the far western Adirondacks.
Any showers should end before cooler temps arrive and allow the
precip to fall in any p-type other than rain.
Long term /Wednesday through Sunday/...
we begin the long term of the forecast with good global model
consensus with our departing storm off the New England coast as high
pressure from Hudson Bay begins its approach and positive influence
across the region. This will keep most of the region dry Wednesday
through Thursday with clearing skies and brisk conditions on
Wednesday to lighter winds into Thursday. Temperatures will slowly
moderate as those sub zero h850 temperatures Wednesday climb toward
0c by days end Thursday. Daytime highs mainly into the 40s with
some lower 50s for valley locations. Overnight lows mainly into the
20s Wednesday night.
This all changes toward the end of this week and into the weekend.
Short wave trough axis was coming ashore across central California
and Oregon's coasts. Global model consensus favors with tracking
this wave across The Four-Corners region and into the Southern
Plains at the start of the long term forecast period. Ample Gulf of
Mexico moisture begins to become entrained as this storm develops
and begins to track northeast across the central Mississippi River
valley and Ohio Valley Thursday night into early Friday. While the
surface low is forecast to track across the Great Lakes region,
impressive low level jet and moisture advection will spread
precipitation into the region through Friday. As the surface high
slides to our northeast, thermal column appears to be cold enough
for the onset of precipitation to fall initially as snow. Then as
the warm advection evolves and strengthens, we will see a changeover
to mainly rain for this event later Friday.
Then models begin to diverge Friday night into first day of April on
Saturday. The GFS wants to further develop a coastal low which will
aid in colder air advecting back into our region while the Canadian
is similar but a more pronounced cold air damming signature. The
European model (ecmwf) is very progressive with ending the precipitation through
Saturday. For now, combination of the blended approach and wpc for
likely pops Friday into Friday night with a tapering off to
scattered pops for the first half of the weekend. With a blended
approach utilized, the chance for snow mixing back in is possible
mainly into the higher terrain.
Somewhat drier air is expected for the second half of the weekend.
Some terrain enhanced clouds and perhaps a shower is possible as
moisture and April sun angle may assist with shower development.
Aviation /12z Monday through Friday/...
thanks to an approaching warm front, steady rainfall is moving
into the area. This rainfall is allowing for MVFR/IFR conditions
at all taf sites due to both visibility and ceilings, although
it generally be IFR through much of the morning hours as
ceilings will mainly be below 1000 ft. S-southeast winds will be 5 to
10 kts, although there have been a few higher gusts at kalb so
far this morning.
Temperatures are generally at or just above freezing, so a brief
period of freezing rain is possible at kgfl/kpsf for the next
hour or so. Otherwise, precip will just be in the form of a cold
rain for this morning as temperatures slowly warm up through the
30s. 2 kft winds will be around 30 kts over western New
England, so will allow for a period of low level wind shear this morning at kpsf
This afternoon, steady rainfall should end by around 17z-18z or
so, allowing for visibility to improve. However, plenty of
lingering low clouds will keep MVFR conditions around. There
still may be a few showers around this afternoon into early this
evening, so will include a prob30 to account for this
possibility. IFR conditions look to return for tonight thanks to
the abundant low clouds and low level moisture, along with light
or calm winds, leading to the developing of fog and stratus.
Tuesday through Tuesday night: moderate operational impact.
Chance of rain showers.
Wednesday through thursday: no operational impact. No sig weather.
Thursday night: low operational impact. Slight chance of snow.
Friday: high operational impact. Likely rain...sn.
most areas continue to have snow on the ground. Damp conditions
are expected for today into tomorrow with light winds. Some
clearing is expected by Wednesday.
as a warm front moves across the region, a period of rainfall is
expected today, with the bulk of the rain coming this morning.
In addition, milder temperatures will return by this afternoon,
which will allow for some additional snow melt today through
Some additional rain showers are possible tomorrow with the
passage of a cold front before dry weather returns for
Wednesday into Thursday. About one to three quarter(s) of an
inch of rain is expected between today and tomorrow. This
rainfall, along with the expected snowmelt, will cause some
rises on rivers and streams. However, this rain and snowmelt
won't be enough to cause any flooding. The latest mmefs supports
this as well, with just a few river points nearing action stage,
but no sign of any flooding expected this week.
Some additional precipitation in the form of rain and snow is
expected for Friday into Saturday.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
advanced hydrologic prediction service /ahps/ graphs on our
CT...Freezing Rain Advisory until noon EDT today for ctz001.
Massachusetts...Freezing Rain Advisory until noon EDT today for maz001-025.
Vermont...Freezing Rain Advisory until noon EDT today for vtz013>015.