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Office: ALY

FXUS61 KALY 111131
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
631 AM EST Mon Dec 11 2017

.SYNOPSIS...
As lake effect dissipates today, we await our next winter
weather event. Snow will overspread most of the region overnight
Monday and continue through Tuesday. Some warmer air may allow
for snow to mix with rain from Albany and points southward
through the Hudson River Valley. Brisk and colder weather is
expected for the middle of the week in the wake of this storm.

&&

.NEAR TERM /UNTIL NOON TODAY/...
As of 630 AM EST...Winter Weather Advisory cancelled for
northern Herkimer and western Hamilton counties.

Lake effect plume off Ontario has weakened significantly as
radar reflectivity depicts returns are around 20DBz or less.
Hence we have cancelled the winter weather advisory. Otherwise,
some flurries across the terrain will also dissipate as cloud
break for sunshine for a tranquil start to the work and school
week. As partial snow cover and low sun angle, we will favor a
blended approach of the guidance at this time.

&&

.SHORT TERM /NOON TODAY THROUGH 6 PM TUESDAY/...
 ...Winter Storm Watch continues for the Dacks, Lake George
Saratoga Region into southern Vermont...
 ...Winter Weather Advisory has been issued for the
Berkshires...

Breaks of sunshine will become filtered with additional higher
and mid level clouds later in the afternoon into the evening
hours. H2O vapor loop shows rather impressive and compact wave
crossing across the Dakotas into Minnesota. This Alberta Clipper
will initiate surface cyclogenesis across the lower Great Lakes
and result with impressive isentropic lift across the northeast
corridor overnight into Tuesday. As stated in the previous AFD,
snow is expected across the entire region Tuesday morning as
surface low deepens to around 990mb Tuesday afternoon.
Difference this run is the attempt for some warmer air to advect
into the mid levels from Albany and points southward through
the Hudson River Valley for some rain/snow mixture. While this
will cut down on overall accumulations, any slight deviations to
the thermal profiles will influence the snow accumulations. Per
extensive collaboration with neighboring offices and WPC
guidance, we will continue with the winter storm watch for those
areas already highlighted, and issue a winter weather advisory
for the Berks. Additional expansion of the advisory is expected
later today. Overnight lows in the 20s and highs Tuesday climb
into the 30s for most of the region with near 30F for the Dacks.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
An active and wintry pattern will continue into next work week
as a longwave trough persists over the eastern CONUS. While we
will be monitoring numerous shortwaves rotating into the
Northeast which will present a number of snow threats, model
agreement remains poor on exact timing, placement and intensity
of each shortwave. However, we have higher confidence in a
period of below normal temperatures impacting eastern NY/western
New England Wednesday - Friday.

Tuesday night, the surface low and associated snowfall will be
lifting into New England as cold air quickly filters into the
region. A dry slot, evident in the model RH fields, will nose
northward across eastern New York/western New England behind the
surface low. This will help cut off the snowfall during the
overnight period, with some snow showers lingering in the
Adirondacks.

During the day on Wednesday, the closed upper low will pass through
the area, with some light snow showers possible. On the back side of
this system, cold air flowing over the relatively warm lakes could
lead to continued lake effect snow, especially in the Adirondacks
and Mohawk Valley. Northwest flow will also lead to cold air
advection and the start of cold temperatures in our region. H850
isotherms fall to -15C to -20C throughout the day with little to no
rise in afternoon temperatures. Blustery winds will also set in
during the day with gusts of 30-40 mph possible, especially in the
high terrain locations. These below normal temperatures, along with
northwest flow, will lead to temperatures dropping towards 0 degrees
in the Adirondacks to teens elsewhere Wednesday night. Wind chills
overnight could fall into the negative teens in the Adirondacks
overnight so we'll be keeping a close eye if any wind chill advisory
headlines will be needed.

High pressure tries to nose in from Canada during the day Thursday
and the change in flow regime plus subsidence should suppress the
lake effect snow bands. Outside of lake effect snow chances,
locations should stay dry.

Chilly temperatures remain in placement Thursday - Friday with high
temperatures likely only rising into the upper teens to upper 20s
and lows in the teens/single digits which is about 10 - 15 degrees
below normal for mid-December. Our next shortwave exits the Great
Lakes and heads into our area bringing the next threat for snow
Friday - Saturday. While some moisture is associated with this
disturbance, poor model agreement remains on placement, timing and
intensity giving us a low confidence forecast on snow potential.

Rising heights are possible in the wake of this upper disturbance
leading to the flow regime shifting to W or even SW with
temperatures rebounding closer to normal heading into the weekend.
However, additional shortwaves are expected to traverse the
Northeast late in the weekend into early next week which will once
again bring additional threats for snow.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected the remainder of the overnight and
into the day on Monday. With an upper level trough overhead and
lake-effect snow upstream of the area, there will continue to
bkn-ovc cigs around 4-9 kft, esp for KGFL/KALB. Otherwise,
light and variable winds or s-sw winds of around 5 kts is
expected through the overnight hours with no precipitation
expected.

Daylight hours on Monday, there will be sct-bkn cigs around 4-6
kft with no precip through the day. Westerly winds will be
around 10 kts. Some mid level clouds may increase towards
evening as the next storm system approaches from the west.
Chance of snow appears to be after this TAF forecast cycle.

Outlook...

Tuesday Night: Moderate Operational Impact. Chance of SN.
Wednesday: Moderate Operational Impact. Breezy Chance of SN.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night:  Slight Chance of SN.
Friday: Moderate Operational Impact. Chance of SN.
Friday Night: Low Operational Impact. Slight Chance of SN.
Saturday: No Operational Impact. NO SIG WX.

&&

.HYDROLOGY...
No hydrologic problems are expected through the week ahead.

Cold weather with periods of snow and snow showers are forecast.
Ice will form and thicken on area lakes and rivers and some
river gauges may start to show erroneous readings due to ice by
the end of the week.

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.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Storm Watch from late tonight through late Tuesday
     night for NYZ032-033-038-039-041>043-050-082>084.
MA...Winter Weather Advisory from 1 AM Tuesday to 1 AM EST
     Wednesday for MAZ001-025.
VT...Winter Storm Watch from late tonight through late Tuesday
     night for VTZ013>015.

&&

$$
SYNOPSIS...BGM
NEAR TERM...BGM/OKeefe
SHORT TERM...BGM/OKeefe
LONG TERM...JVM/Speciale
AVIATION...Frugis/BGM
HYDROLOGY...BGM/OKeefe

FXUS61 KALY 111138
AFDALY

Area Forecast Discussion
National Weather Service Albany NY
638 AM EST Mon Dec 11 2017

.SYNOPSIS...
As lake effect dissipates today, we await our next winter
weather event. Snow will overspread most of the region overnight
Monday and continue through Tuesday. Some warmer air may allow
for snow to mix with rain from Albany and points southward
through the Hudson River Valley. Brisk and colder weather is
expected for the middle of the week in the wake of this storm.

&&

.NEAR TERM /UNTIL NOON TODAY/...
As of 630 AM EST...Winter Weather Advisory cancelled for
northern Herkimer and western Hamilton counties.

Lake effect plume off Ontario has weakened significantly as
radar reflectivity depicts returns are around 20DBz or less.
Hence we have cancelled the winter weather advisory. Otherwise,
some flurries across the terrain will also dissipate as cloud
break for sunshine for a tranquil start to the work and school
week. As partial snow cover and low sun angle, we will favor a
blended approach of the guidance at this time.

&&

.SHORT TERM /NOON TODAY THROUGH 6 PM TUESDAY/...
     Winter Storm Watch continues for the Dacks, Lake George
Saratoga Region into southern Vermont...
 ...Winter Weather Advisory has been issued for the
Berkshires...

Breaks of sunshine will become filtered with additional higher
and mid level clouds later in the afternoon into the evening
hours. H2O vapor loop shows rather impressive and compact wave
crossing across the Dakotas into Minnesota. This Alberta Clipper
will initiate surface cyclogenesis across the lower Great Lakes
and result with impressive isentropic lift across the northeast
corridor overnight into Tuesday. As stated in the previous AFD,
snow is expected across the entire region Tuesday morning as
surface low deepens to around 990mb Tuesday afternoon.
Difference this run is the attempt for some warmer air to advect
into the mid levels from Albany and points southward through
the Hudson River Valley for some rain/snow mixture. While this
will cut down on overall accumulations, any slight deviations to
the thermal profiles will influence the snow accumulations. Per
extensive collaboration with neighboring offices and WPC
guidance, we will continue with the winter storm watch for those
areas already highlighted, and issue a winter weather advisory
for the Berks. Additional expansion of the advisory is expected
later today. Overnight lows in the 20s and highs Tuesday climb
into the 30s for most of the region with near 30F for the Dacks.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/...
An active and wintry pattern will continue into next work week
as a longwave trough persists over the eastern CONUS. While we
will be monitoring numerous shortwaves rotating into the
Northeast which will present a number of snow threats, model
agreement remains poor on exact timing, placement and intensity
of each shortwave. However, we have higher confidence in a
period of below normal temperatures impacting eastern NY/western
New England Wednesday - Friday.

Tuesday night, the surface low and associated snowfall will be
lifting into New England as cold air quickly filters into the
region. A dry slot, evident in the model RH fields, will nose
northward across eastern New York/western New England behind the
surface low. This will help cut off the snowfall during the
overnight period, with some snow showers lingering in the
Adirondacks.

During the day on Wednesday, the closed upper low will pass through
the area, with some light snow showers possible. On the back side of
this system, cold air flowing over the relatively warm lakes could
lead to continued lake effect snow, especially in the Adirondacks
and Mohawk Valley. Northwest flow will also lead to cold air
advection and the start of cold temperatures in our region. H850
isotherms fall to -15C to -20C throughout the day with little to no
rise in afternoon temperatures. Blustery winds will also set in
during the day with gusts of 30-40 mph possible, especially in the
high terrain locations. These below normal temperatures, along with
northwest flow, will lead to temperatures dropping towards 0 degrees
in the Adirondacks to teens elsewhere Wednesday night. Wind chills
overnight could fall into the negative teens in the Adirondacks
overnight so we'll be keeping a close eye if any wind chill advisory
headlines will be needed.

High pressure tries to nose in from Canada during the day Thursday
and the change in flow regime plus subsidence should suppress the
lake effect snow bands. Outside of lake effect snow chances,
locations should stay dry.

Chilly temperatures remain in placement Thursday - Friday with high
temperatures likely only rising into the upper teens to upper 20s
and lows in the teens/single digits which is about 10 - 15 degrees
below normal for mid-December. Our next shortwave exits the Great
Lakes and heads into our area bringing the next threat for snow
Friday - Saturday. While some moisture is associated with this
disturbance, poor model agreement remains on placement, timing and
intensity giving us a low confidence forecast on snow potential.

Rising heights are possible in the wake of this upper disturbance
leading to the flow regime shifting to W or even SW with
temperatures rebounding closer to normal heading into the weekend.
However, additional shortwaves are expected to traverse the
Northeast late in the weekend into early next week which will once
again bring additional threats for snow.

&&

.AVIATION /12Z MONDAY THROUGH FRIDAY/...
VFR conditions are expected throughout the day today. With an
upper level trough overhead, there will be sct-bkn cigs around
4-6 kft with no precip through the day. Westerly winds will be
around 10 kts. Some mid level clouds may increase towards
evening as the next storm system approaches from the west.
Chance of snow looks to arrive between 05-09Z/Tue where light to
moderate snow is possible. Conditions could be reduced to MVFR
or high-end IFR by the end of the TAF period.

Outlook...

Tuesday Night: Moderate Operational Impact. Chance of SN.
Wednesday: Moderate Operational Impact. Breezy Chance of SN.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night:  Slight Chance of SN.
Friday: Moderate Operational Impact. Chance of SN.
Friday Night: Low Operational Impact. Slight Chance of SN.
Saturday: No Operational Impact. NO SIG WX.

&&

.HYDROLOGY...
No hydrologic problems are expected through the week ahead.

Cold weather with periods of snow and snow showers are forecast.
Ice will form and thicken on area lakes and rivers and some
river gauges may start to show erroneous readings due to ice by
the end of the week.

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.

&&

.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Winter Storm Watch from late tonight through late Tuesday
     night for NYZ032-033-038-039-041>043-050-082>084.
MA...Winter Weather Advisory from 1 AM Tuesday to 1 AM EST
     Wednesday for MAZ001-025.
VT...Winter Storm Watch from late tonight through late Tuesday
     night for VTZ013>015.

&&

$$
SYNOPSIS...BGM
NEAR TERM...BGM/OKeefe
SHORT TERM...BGM/OKeefe
LONG TERM...JVM/Speciale
AVIATION...Frugis/BGM/JVM
HYDROLOGY...BGM/OKeefe



Office: OKX FXUS61 KOKX 111433 AFDOKX Area Forecast Discussion National Weather Service New York NY 933 AM EST Mon Dec 11 2017 .SYNOPSIS... High pressure briefly builds today. Low pressure will then pass across the Great Lakes tonight, while an associated warm front lifts through Tuesday morning. A strong cold front passes in the afternoon. Low pressure will move into the Canadian Maritimes Tuesday night into Wednesday night, with brief high pressure building across the area in its wake. A weak Alberta Clipper passes to the south on Thursday, followed by a low pressure system passing off the coast late Friday into Friday night. High pressure returns for the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Upper shortwave passing this morning. Westerly fetch producing clouds across the LI sound seen on visible and radar, as shortwave passes. Otherwise, sunshine will give way to an increase in clouds later today. Winds diminish as high pressure begins to briefly build across the area. High temperatures today will top out in the upper 30s to lower 40s per latest hourly guidance. && .SHORT TERM /6 PM THIS EVENING THROUGH 6 PM TUESDAY/... Low pressure moves across the Great Lakes tonight into Tuesday morning. The associated warm front approaches the area from the south late tonight into Tuesday with increasing chances of precipitation, followed by a strong trailing cold front Tuesday afternoon. Warm advection ahead of the main portion of the storm will make this a mixed precip event. Rain is forecast for the city, adjacent suburbs and coastal section, although some snow can mix in at first. Across inland areas, snow or a snow/rain mix changes over to rain as Temperatures rise during the morning hours on Tuesday. Snow accumulations expected to be 1 or 2 inches for the northern suburbs, with 2 to 3 inches expected further north across Orange County. Less than an inch is expected anywhere else where snow manages to accumulate. Highs on Tuesday will be in the upper 30s to lower 40s inland and mid to upper 40s along the coast, with even some 50 degree readings for Long Island. && .LONG TERM /TUESDAY NIGHT THROUGH SUNDAY/... A period of brisk weather is anticipated Tuesday night into Thursday as an intensifying low pressure system moves towards the Canadian Maritimes. With the tightening pressure gradient on the back side of the low, strong cold advection combined with sustained winds around 20-30 mph and gusts above 40 mph will lead to wind chill values in the single digits to teens on Wednesday, and largely the single digits to near zero Wednesday night. Although some moderation will occur on Thursday as flow backs to the WSW ahead of the next system, temperatures will remain well below climatological normals, with cold wind chill values in lingering breezy flow. Overall, a blocking pattern with low pressure anchored over the East Coast will continue a period of below normal temperatures and above normal precipitation as a series of waves rotate around the broader low. Chances of precipitation increase again into Friday as the subtropical jet shifts northward, combining with polar energy and leading to the development of a coastal low. The general track and intensity of the low will need to be monitored, but expected at least a slight chance of snow showers across the interior and perhaps a rain/snow mix along the coast into Friday night. Gusty flow and below normal temperatures will once again be possible as the low departs, with a slow moderation occurring through the weekend as high pressure builds across the area. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... A cold front will move across the area today. VFR today and early tonight. Cigs fall to MVFR late in the TAF period, mainly after 09z Tuesday as a warm front pushes north of the area and associated low pressure system passes north of the area. precipitation starts after 06z, mainly in the form of a mix of rain and snow for most terminals, except KSWF, where precipitation should be all snow. As warmer air works into the the coastal locations, precipitation should quickly change over to all rain. Interior locations should stay snow through at least 12z Tuesday. Generally westerly winds today. There may be a few occasional gusts this morning, then gusts become more frequent during the afternoon with speeds around 20 kt. Gusts will end after 23Z. Tonight, winds become more southerly and remain less than 10 kt. NY Metro Enhanced Aviation Weather Support... Detailed information, including hourly TAF wind component forecasts, can be found at: http:/www.weather.gov/zny/n90 KJFK TAF Comments: Gusts this afternoon may be occasional. The afternoon KJFK haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KLGA TAF Comments: Gusts this afternoon may be occasional. The afternoon KLGA haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KEWR TAF Comments: Gusts this afternoon may be occasional. The afternoon KEWR haze potential forecast is GREEN...which implies slant range visibility 7SM or greater outside of cloud. KTEB TAF Comments: Gusts this afternoon may be occasional. KHPN TAF Comments: Gusts this afternoon may be occasional. KISP TAF Comments: Gusts this afternoon may be occasional. .OUTLOOK FOR 12Z TUESDAY THROUGH FRIDAY... .Tuesday...MVFR or lower possible with a wintry mix to rain at northern terminals and rain at southern terminals. Conditions improve to VFR Tuesday afternoon. SE-SW winds G15-25KT possible. .Tuesday night-Wednesday...Mainly VFR, with a chance of MVFR in snow showers. W-NW winds G20-35KT probable. .Wednesday night-Thursday night...VFR. W-SW winds G15-25KT possible. .Friday...MVFR possible with snow. W-NW winds G15-20KT possible. && .MARINE... As high pressure begins to build across the area, gusts will gradually begin to diminish, with seas slowly subsiding on the ocean waters later today. Winds and seas then increase again on Tuesday, with SCA conditions becoming likely on the area waters. By Tuesday night, gale- force winds will be possible as an intensifying low pressure system ejects into the Canadian Maritimes. Gusty flow and at least SCA-level conditions will continue into Thursday before gradually subsiding into Thursday night as flow weakens across the area. Relatively tranquil conditions persist through Friday before winds and seas increase into Friday night behind a departing low pressure system. && .HYDROLOGY... No significant hydrologic impacts expected. && .EQUIPMENT... NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) is off the air for an extended period of time. See our headline news on the web at: http:/weather.gov/nyc The Riverhead NOAA Weather Radio Station WXM-80 (162.475 MHz) is currently out of service. NWS technicians are working with Verizon to restore service. An estimated time of return to service is not currently known. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 PM EST this evening for ANZ350- 353-355. && $$ SYNOPSIS...MD/Fig NEAR TERM...MD/Fig/PW SHORT TERM...Fig LONG TERM...MD AVIATION...BC/IRD MARINE...MD/Fig/PW HYDROLOGY...MD/Fig EQUIPMENT...
Office: BUF FXUS61 KBUF 111453 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 953 AM EST Mon Dec 11 2017 .SYNOPSIS... Surface high pressure briefly builds across the region with fair and largely dry weather today. Low pressure will then cross the region bringing periods of widespread accumulating snow that will last through Wednesday. Several additional weak systems will then cross the area late in the week along with additional chances of snow. && .NEAR TERM /THROUGH TONIGHT/... Regional radars show some areas of very light snowfall and flurries across the forecast area this morning. With sfc high building in from the west no significant additional snowfall accumulation anticipated for the remainder the morning hours. Otherwise we can expect a welcome quiet and largely dry day under the transient surface ridge...with daytime highs ranging from the lower to mid 20s across the North Country to the upper 20s/near 30 elsewhere. Tonight...our brief period of fair and dry weather will quickly come to an end...as a slowly strengthening surface low pushes eastward from the Upper Great Lakes. Increasing warm air advection/isentropic upglide out ahead of this system will result in widespread light snow spreading across the region from west to east...with the snow picking up a bit during the overnight hours as the main surface low pushes to our western doorstep...and available moisture/lift both ramp up. At this point total nighttime snowfall accumulations appear as if they will range from 1-2 inches...with a few spots potentially receiving between 2-3 inches. Low temps will range from around 20 east of Lake Ontario to the mid 20s elsewhere and should occur during the first half of the night...before giving way to slowly rising temps overnight in the warm advection regime out ahead of the approaching surface low. && .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/... ...Accumulating synoptic snows will transition to another potentially significant lake effect snow event... The clipper low will be in the process of passing across the region Tuesday morning. Widespread accumulating synoptic snows will be ongoing. Ascent from this storm looks to be driven by warm advection with particularly impressive isentropic lift. 00z NAM/GFS/GEM all pretty similar in QPF guidance and supportive of additional snowfall amounts of 2-3 inches through Tuesday morning. As the surface low starts to push across northern New York Tuesday afternoon, winds will veer to west then northwest while becoming rather gusty as cold advection sets in. Winds in the wake of the systems cold front may peak near 45 mph, especially south of the low center across the western Southern Tier driving wind chills into the teens. Later Tuesday into Wednesday, a transition will take place into another potentially significant lake effect snow event. Lake enhanced/effect snows are expected to develop south or southeast of the lakes as 850 mb temperatures cool in a northwest flow regime. Profiles indicating many favorable lake effect parameters including extreme over-lake instability, equilibrium heights rising to near 15k feet and sufficient synoptic moisture and lift intersecting the dendritic snow growth zone. Tuesday night into Wednesday will likely be the most significant time period of accumulating lake snows with equilibrium level peaking. Strong winds could bring additional impacts with travel conditions expected to be hazardous in heavy snow and blowing snow. The core of the anomalously deep upper level low will pass over our region Tuesday night and Wednesday which will bring the coldest air yet this month with lows dipping into the single digits to teens Tuesday night and only peaking in the teens to maybe 20 on Wednesday. Lake effect then continues to look like it will begin to weaken later Wednesday night as high pressure over the Ohio Valley is forecast to nose north into western New York. && .LONG TERM /THURSDAY THROUGH SUNDAY/... Medium range guidance continues to indicate two more clipper lows working across the Great Lakes later this week and next weekend. A fair amount of uncertainty remains regarding the timing and tracking of either of these clipper lows as well as any potenial lake enhancement. Have continued broadbrush chance POPs for snow showers through Saturday until more certain details arise in newer guidance. Temperatures will remain below average through the end of the week, as the region will remain embedded within longwave troughiness. The eastern trough may break down over the weekend which would potentially allow warmer air to return to our region. Blend of model temperature guidance indicates temps may rise back to normal by Saturday and possibly above normal for Sunday. If this occurs rain/snow would be possible Sunday. Longer range guidance suggests that this break from the cold may only be temporary, as a longwave trough becomes re-established over the East in the week following. && .AVIATION /15Z MONDAY THROUGH FRIDAY/... Regional radars show some areas of light snowfall and flurries this morning. This light snow is producing some lower VSBYS/CIGS resulting in IFR/MVFR east and southeast of both Lakes Erie and Ontario. However, as the surface high continues to build in from the west conditions will improve by early this afternoon with mainly VFR across the forecast area. These improved flying conditions will then deteriorate back to IFR from west to east tonight as low pressure advances eastward across the Great Lakes and spreads widespread light snow across the region. Outlook... Tuesday through Wednesday...Widespread IFR in periods of snow. Thursday and Friday...Areas of MVFR/IFR with snow showers likely. && .MARINE... Weak high pressure will build across the region today...with winds tending light and variable by midday/early afternoon. As a result... lingering advisory-level conditions across portions of Lake Ontario will come to an end this morning...with fairly quiet conditions then following for this afternoon. Low pressure tracking eastward from the Upper Great Lakes will then pass directly overhead late tonight and Tuesday morning. Winds will increase in the wake of this system Tuesday through Wednesday...with another period of solid Small Craft Advisory conditions expected areawide. On Lake Erie...it is not out of the question that conditions could approach or even reach marginal gale force levels from Tuesday into early Tuesday evening...however at this point confidence in this remains too low for a Gale Watch. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...Winter Storm Watch from 7 PM EST this evening through Wednesday afternoon for NYZ001>008-010>012-019-020-085. MARINE...None. && $$ SYNOPSIS...AR/JJR NEAR TERM...AR/JJR SHORT TERM...TMA LONG TERM...SMITH AVIATION...AR/JJR MARINE...AR/JJR
Office: BGM FXUS61 KBGM 111148 AFDBGM Area Forecast Discussion National Weather Service Binghamton NY 648 AM EST Mon Dec 11 2017 .SYNOPSIS... After scattered morning snow showers and flurries, things will be fairly quiet until a clipper system quickly moves through tonight into early Tuesday with accumulating snow. Lake effect snow will follow for Tuesday afternoon through Wednesday night in Central New York and perhaps some of the Northern Tier of Pennsylvania, as Arctic air descends across the region. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... 645 AM Update... We were able to drop the winter weather advisory earlier, that had been in effect for Northern Oneida, since snowfall rates/banding were already significantly diminishing. That being said, around an inch or so of fluff will be possible from the last vestiges of lake effect this morning. Clipper system tonight-early Tuesday, plus the Arctic air and lake effect snow that will follow, are the main forecast concerns in the big picture. For details on that please refer to the short term portion of this area forecast discussion. Previous discussion... Lake Ontario band shifted north of the area much of yesterday, but with approach of a shallow cold front it is now reorienting as of 3 AM. It will bodily carry through northern Oneida county during the next several hours, likely reducing visibility to about a mile while dropping another quick 1 to 2 inches north of the NY Thruway. We will allow Winter Weather Advisory to continue up to the scheduled expiration of 7 AM this morning. As winds veer northwesterly behind the front, inversion heights will also rapidly drop to below the dendritic growth zone, which along with drier air will allow the lake effect to transition to multi-band snow showers and flurries after dawn this morning, before ending around midday. So south of the Thruway to about as far as Moravia-Cortland-Pharsalia-Morrisville-Waterville, accumulations this morning should be limited to a fluffy dusting to around an inch. Elsewhere just a few flurries are expected as the weak front passes; many locations especially in Northeast PA will see nothing at all due to the amount of dry air. Though there will be a gradual decrease in lake clouds, high thin clouds will quickly stream in ahead of the approaching clipper, and then thicken with time. This will hold highs back to generally in the mid 20s to mid 30s range. && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... 400 AM Update...The highly advertised clipper low will strengthen as it tracks across the Great Lakes and into New York tonight and Tuesday. Light snow will break out in isentropic lift regime over CNY and NEPA by late evening with best forcing across NY portion of forecast area. Snow picks up with time heading into the Tuesday commute. Warm advection appears to be split into lift and warming of the boundary layer enough to significantly affect snow-liquid ratios and surface temps tomorrow morning. Arctic front with falling temperatures arrives late afternoon. The favorable dendrite crystal layer rises tonight to about 10K-13K feet with relatively mild air beneath. Dry slot also noted to come into play as strong jetlet rounds base of upper low Tuesday. Snow totals will not be easy with this one due to the above factors as there will likely be insufficient flake production, some stoppage of precip at times, and low level warming to melt what falls, or even provide some liquid flakes in some of the warmest locales. Looking for a quick 1-3"/2-4" accumulation in a S-N gradient overnight and nominal accums on Tuesday with some melting. Given this uncertainty, have held off on issuing winter advisories across the Southern Tier and NEPA pending further review. We have issued a Winter Storm Watch through Wednesday across the northern zones where confidence in several inches is highest. It looks to be just a tad colder overall, coupled with topographic enhancement along the Tug Hill and Mohawk Valley. Synoptic and hi-resolution models were simulating this with a QPF bullseye in this area. In addition...a good set up for LES along a 290-310 flow develops later Tuesday night and Wednesday post Arctic frontal passage. Lapse rates beneath inversion layer appear stout with limited shear and good support from synoptic moisture. Thus, multi-single band hybrid lake effect/enhancement should produce healthy squalls and accumulations through Wednesday for the Syracuse area and hilltowns to the south. A good portion of the area southeast of Lake Ontario is likely to see a bunch of snow by Wednesday afternoon. Watch (and/or Warnings) may need to be expanded slightly depending on confidence of inland extent to snow plumes. Turning much colder by Wednesday with highs struggling in the teens to lower 20s. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... 400 AM Update...No significant changes to medium range with long wave pattern remaining in a broad trof and models consistent with 12Z runs. Previous discussion... Flow becomes more westerly and relaxes on Thursday so snow showers will taper off. However, unsettled weather will continue through Friday with trofiness aloft, a clipper moving into the Great Lakes, and systems running up the coast to our east. Confidence in forecast is low to moderate until Friday when global models diverge quite a bit on positioning and timing of disturbances diving around the base of the trof and interacting with the front along the coastal plain. Chance PoPs during this time and some moderation of temperatures with flatter flow and slight warm advection. Temperatures look to potentially warm above freezing into the mid-30s to lower 40s by next Sunday, as a storm system passes by well to our north. This system will bring chances for rain and snow showers, and perhaps some mixed precipitation. && .AVIATION /12Z MONDAY THROUGH FRIDAY/... Lake effect snow is winding down this morning, but between 12Z-15Z there will still be times of 1-4 mile visibility for KRME-KSYR. Brief high end MVFR ceiling and a light flurry will still initially be around KBGM-KITH, otherwise all terminals will go to VFR late morning through early evening. Wind is veering to west-northwest but less than 10 knots, becoming variable late afternoon to southeast tonight. With this busy pattern, a clipper system will already start moving across the region from 03Z onward with IFR to fuel alternate required conditions becoming likely through dawn Tuesday. Outlook... Tuesday morning...Lingering restrictions as a clipper system finishes moving through the region. Tuesday afternoon through Wednesday night...Gusty snow showers and associated restrictions, especially NY terminals. Thursday through Friday...Still a chance for snow showers and intermittent restrictions. && .BGM WATCHES/WARNINGS/ADVISORIES... PA...None. NY...Winter Storm Watch from this evening through Wednesday afternoon for NYZ009-018-036-037. && $$ SYNOPSIS...MDP NEAR TERM...MDP SHORT TERM...JAB LONG TERM...JAB/MJM AVIATION...MDP