Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus61 kaly 261706 
afdaly

Area forecast discussion
National Weather Service Albany New York
106 PM EDT Fri may 26 2017

Synopsis...
low pressure will move northeast of the Gulf of Maine this afternoon
with isolated to scattered showers mainly from the capital region
north and east, otherwise it will be cloudy and cool. Then the
Holiday weekend starts off mainly dry and seasonable before the
threat for showers and possibly a few thunderstorms returns Sunday
night into Monday.

&&

Near term /until 6 PM this evening/...
as of 100 PM, still a generous coverage of showers north and
east of a Raquette Lake, New York to Saratoga Springs, New York to
Cheshire, Massachusetts line. These showers are within a midlevel
deformation zone and area of greater 700-500 mb Theta-E wrapping
into the western flank of the nearly-stacked cyclone centered
over the Gulf of Maine. Hi-res solutions indicate this activity
only slowly retreating northeastward in conjunction with the
upper low's slow departure, so have continued likely pops
through 21z before tapering to chance. South and east of this
area of steady rainfall, showers will be much more isolated,
with possibly a bit more activity across the Catskills. Cloudy
skies will continue, resulting in temperatures not budging
upward too much from where they are now in the 50s and lower
60s. The exception is over far southern portions of the
Catskills and Mid-Hudson valley where a few breaks of clouds
were noted and temps could briefly spike to near 70.

Previous discussion...as of 1041 am EDT...a 998 hpa cyclone
according the latest 1400 UTC rap has moved into the Gulf of
Maine with bands of moisture in the cyclones mid and upper level
deformation continuing to impact portions of eastern New York and
western New England. The cyclone has closed off at 500 hpa over
eastern New England with spokes of short-wave energy rotating
around the system. The pops were retooled with the higher values
mainly from the the capital region north and east with some
orographic upslope enhancement along The Spine of the southern
greens,Taconics,Berkshires. Locations south and west will likely
see isolated to scattered showers until the early PM, but the
activity should continue to wane based on the latest 3-km hrrr
and 4-km NAM in those areas. We kept at least scattered showers
in for the afternoon for locations to the north in the moist
cyclonic flow. As the latest GOES-16 visible/infrared imagery shows
cloudy conditions to prevail. The best chance of a few breaks in
the clouds will be near the Mid-Hudson valley/northwest CT/extreme
southeast Catskills in the late PM.

As coastal storm deepens slightly to 995 hpa, the sfc pressure
gradient will become a bit tighter as surface winds will be on
the breezy side this afternoon. Due to considerable cloud
coverage, high temperatures today will be similar to thursdays
and a good compromise to the 00z MOS. Mainly 60s to near 70f for
the capital region and southward toward the Mid-Hudson River
Valley with mainly 50s elsewhere, especially over the higher
terrain.

&&

Short term /6 PM this evening through Saturday night/...
the coastal storm impacts continue to wane as this feature
tracks further eastward. This will reduce shower coverage and
wind field across the region into the evening hours. However,
rather moist cyclonic flow regime remains in place so partly to
mostly cloudy skies should prevail overnight. Temperatures
mainly into the 50s which is near climatology for this time of
the year.

Overall model consensus now favors another weak short wave
tracking southeast through the daylight hours Saturday.
Meantime, anticyclonic surface field is increasing from the
west. So overall shower coverage will be rather isolated and
mainly across the higher terrain where we will place the pops/wx
at this time (dacks, Mohawk Valley and Catskills at this time
where the deeper moisture profiles are progged). Highs Saturday
afternoon are expected to range between 65-70f.

Saturday night, short wave ridging and rising surface pressures
should allow for additional breaks in the clouds and dry weather
conditions overnight. As partial clearing and light winds, we
will watch for the development of some fog that later shifts
will evaluate and add once confidence levels increase. We
discounted the GFS with its rather north bias of upstream short
wave as NAM/ggem/ECMWF and ensemble members were further south
and west of the region.

&&

Long term /Sunday through Thursday/...
an unsettled weather pattern is expected through much of the long
term period as a slow moving upper level trough approaches the
northeast from the Great Lakes.

At the start of the period, weak ridging will be in place over the
northeast on Sunday, as a large cutoff upper level low starts to
head towards the western Great Lakes from central Canada. With the
weak ridging in place, most areas look to stay dry for Sunday,
although clouds will generally be increasing through the day. As
the ridge departs, warm advection thanks to south to southwest flow
at low to mid levels may allow for a shower across far western areas
by late Sunday or Sunday evening, but the better chance look to
arrive for Sunday night into Monday. Temps look fairly seasonable
for Sunday with low to mid 70s for valley areas and 50s for Sunday
night.

Have gone with high chc to likely pops for Monday as a sfc warm
front moves across the area with a period of steadier rainfall. With
plenty of clouds and the rain in place, temps will mainly be in the
60s. Have also included a slight chc for thunder, as some elevated
instability could allow for a few rumbles across the region.

The upper level low will slowly move from the Great Lakes on Tuesday
towards the northeast for Wednesday. The storm's cold front looks
to cross through the area on Tuesday, so will continue chance pops
through the day with seasonable temps in the upper 60s to upper 70s.
Being in the storm's warm sector, there may be a few breaks of sun
(especially for valley areas), so will allow for sky cover to vary
between partly to mostly cloudy on Tuesday. Will also include a
slight chc for thunder, as any breaks could allow for some
instability ahead of the advancing cold front.

Behind the front, some additional light rain showers will look to
occur, especially for northern and western areas for Tuesday night
into Wednesday, thanks to the cyclonic flow aloft in place. Will
continue chance pops for rain showers with a partly to mostly cloudy
sky. Temps will continue to be near or slightly below seasonable
levels for late may.

Another shortwave swinging around the main longwave trough over the
northeast could allow for some additional showers for late in the
week as well. Will continue to allow for low chc pops for Thursday
with temperatures just slightly below normal.

&&

Aviation /18z Friday through Wednesday/...
low pressure near kbos will move northeast to the southern Gulf
of Maine late this morning, and then will move slowly east of
New England this afternoon.

Rain in the kalb, kpsf, kpou and kgfl areas will continue
through this morning with mainly MVFR ceilings and visibilities
but some brief periods of IFR in heavier rain in terms of
cigs/vsbys are likely at kalb/kpsf prior to 14z. Some VFR
possible in lulls in the rain in the late morning into the early
afternoon. The rain may slowly decrease in coverage and
intensity this afternoon but ceilings and visibilities should
continue to be predominantly MVFR.

Winds aloft have weakened so there should not be any wind shear.
Generally north-northwest winds at 10 kt or less but gusts over
15 kt later this morning and afternoon hours.

Outlook...

Saturday night: no operational impact. No sig weather.
Sunday: low operational impact. Slight chance of rain showers.
Sunday night: moderate operational impact. Chance of rain showers.
Memorial day: moderate operational impact. Chance of rain showers...tsra.
Monday night: moderate operational impact. Chance of rain showers.
Tuesday: moderate operational impact. Chance of rain showers...tsra.

&&

Fire weather...
showers/periods of rain this morning will become less
widespread during the afternoon, but still expect a cloudy,
cool, and damp day. Slightly warmer and drier Saturday with
light northwesterly winds. A more widespread precipitation activity
is expected to occur Sunday night into early Memorial Day.

&&

Hydrology...
radar estimates suggest a tenth to around a half inch of
rainfall has occurred this far. Coastal storm will likely bring
more rainfall to the region, with up to another half inch
possible. Locally higher amounts could occur along eastern-
facing slopes of the higher terrain. Storm total amounts should
range from around a half into to an inch. River flooding is not
expected at this time.

Showers should taper off through the daylight hours on Friday,
with only light amounts expected. The next potential for
widespread rainfall is expected Sunday night into Memorial Day.

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 website.

&&

Equipment...
the ASOS in Glens Falls at the Floyd Bennett Memorial Airport
continues to experience outages with hourly metars occasionally
missing. This will continue until communications are fully
restored.

&&

Aly watches/warnings/advisories...
CT...none.
New York...none.
Massachusetts...none.
Vermont...none.

&&

$$
Synopsis...bgm/wasula
near term...bgm/Thompson/wasula
short term...bgm
long term...frugis

National Weather Service Glossary of Abbreviations