Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/16/22
AREA FORECAST DISCUSSION
National Weather Service Albany NY
918 PM EST Thu Dec 15 2022
.SYNOPSIS...
A coastal low will approach from the Delmarva Region
tonight bringing wet snow to the most of the region with rain mixing
with snow from Albany south and east especially in the Hudson River
Valley. The snow will be heavy at times north and west of the
Capital Region and over the higher terrain tonight into tomorrow
morning. The coastal low will move near eastern Long Island by
Friday afternoon, and then move east of Cape Cod by Saturday morning
into the afternoon with the snow tapering off. Rain will mix with
snow in parts of the Hudson River Valley and south of the Mass Pike
on Friday before changing back to snow. It will be cold in the wake
of the system for the upcoming weekend with lake effect snow for the
western Adirondacks.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Eastern Albany and southern Washington County were added to
the Winter Storm Warning until 10 am EST Saturday that includes
the southern Adirondacks, Lake George Saratoga
Region, northern Capital Region, Mohawk Valley,
Helderbergs, Schoharie Valley and the eastern Catskills...
Eastern Columbia County was added to the Winter Storm
Warning from 7 pm tonight to 10 am EST Saturday for southern
VT, the Berkshires, northern Litchfield County CT and the
northern Taconics of NY...
Eastern Dutchess County in the southern Taconics was added to
the advisory that includes eastern Ulster, eastern Greene and
western Rensselaer Counties that is in effect until 7 am EST
Saturday...
Leading edge of waves of snow hitting a wall of drier air but
the drier air is retreating. Areas where precipitation is very
light are seeing light rain and sleet and isolated pockets of
freezing sprinkles or drizzle where precipitation is very light
and temperatures are around freezing. Areas seeing the more
intense precipitation are seeing wet bulbing that is cooling low
levels resulting in snow. One wave of more intense
precipitation is tracking into our region and will track east
and northeast through the early morning hours, bringing an inch
or two of snow in some places and a wet and slushy inch or less
in valleys.
NY Mesonet observations showing an inch or two with the band of
snow in higher elevations. Mainly rain in the mid Hudson
Valley. NY Mesonet profiler at KALB showing a warm layer just
above the surface, which is consistent with the rain sprinkles
and sleet we have been seeing so far in the valleys around the Capital
Region. The Helderbergs, eastern Catskills and Schoharie area
have received the most snow so far, around a couple of inches.
We will have to see if more waves of higher intensity
precipitation form in central NY/PA later but just spotty and
scattered precipitation seen in central NY/PA. Again, dustings
to around an inch through this evening in valleys north of the
mid Hudson Valley and maybe 2 or 3 inches in higher peaks of
the eastern Catskills. Some rain mixing in through parts of the
Mid Hudson Valley. Temperatures should hold steady in many areas
through tonight or drop a degree or two where precipitation is
heaviest and wet bulb processes occur. Just minor adjustments to
temperatures and timing of snow through tonight.
PREVIOUS DISCUSSION:
A narrow 500 hPa ridge continues to shift east of New England
with a coastal low pressure system on the eastern flank of the
broad longwave trough over the eastern CONUS with a
closed/cutoff mid and upper low over the Upper Midwest and
western Great Lakes Region early tonight. The primary low
pressure system to this Miller Type B system remains occluded
over southern MN/southwest WI. The area of upper level
diffluence aloft ahead of the secondary coastal low tracking
northeast from the NC/VA coastal border had over running pcpn
developing south and west of the Capital Region.
The coastal low will continue to deepen and intensify as it
moves northeast tonight. The cyclone will be near the left front
quadrant or cyclonic exit region of the H250 jet streak of 125
kts over the Mid Atlantic States overnight, and the poleward jet
entrance region of the oceanic blocking low will be moving down
stream. The isentropic lift will be increasing on the 285K/290K
surfaces with the better upper level dynamics overnight.
Divergence enhances aloft in advance of the jet streak. High
pressure remains anchored near northern Quebec funneling cold
air southward. The H850 LLJ from the east to southeast will
increase to 35 to 50 kts advecting in plenty of Gulf and
Atlantic moisture. PWATS will run +1 to +2 STDEVs above normal
based on the NAEFS and -u wind anomalies /easterlies/ will be 2
to 4 STDEVS above normal. The east/southeast flow will cause
some downsloping issues for the Hudson River Valley tonight, but
will provide strong upslope conditions along the eastern slopes
of the western New England higher terrain, southern Adirondacks
and eastern Catskills. A burst of snow is possible even in the
Hudson River Valley due to the wet bulb and dynamic cooling. The
latest 12Z HREFs do show very high probabilities of 1"/hr rates
for the higher terrain of the eastern Catskills, and
eastern/southern Adirondacks, Berkshires, and southern Greens.
This storm will have a big elevation dependency and sharp
gradients in the snowfall are possible.
Initially, some indications are for a possible laterally
translating snow band per the CSTAR research late tonight. The
soundings are isothermal and we are expecting mainly a snow and
a rain/snow mix with this storm. We went towards the colder 10
percent side of the NBM guidance for temps. BUFKIT profiles
continue to show good dendritic growth/pcpn efficiency
especially from Albany north and west with the strong
omega/upward vertical motion. The low to mid level FGEN also
increases in the 850-700 hPa layer on the NAM/GFS from the I-90
corridor south and east between 06Z-12Z. Snow to liquid ratios
will be in the 6-10:1 range, so we are expecting a heavy wet
snow. Snowfall amounts in the Hudson River Valley may only range
from 1-4" by daybreak FRI, but over the higher terrain 6-12"
and the west-central Mohawk Valley is possible with some
amounts over a foot in the high peaks of the eastern Catskills
and the eastern Adirondacks and southern Greens. Portions of the
Litchfield Hills may have 3-6", as well as the northern Capital
Region. Some impacts are likely with the morning commute. Rain
is expected to mix with snow and possibly change over to all
rain in the mid Hudson River Valley and even the eastern Capital
Region due to the down sloping winds from the east to southeast
at 10-20 mph with some gusts 25-40 mph over the southern
Greens, Berkshires and Taconics.
Lows will be in the upper 20s to lower 30s from wet bulb
cooling and temps will steady or rise in the moderate to heavy
pcpn event for some locations.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
A High Impact Winter Storm continues Friday into Saturday
morning with the headlines remaining in place for most of
eastern NY and western New England.
Tomorrow...the heavy wet snow continues as the coastal low moves
northeast from southern NJ to near eastern Long Island by the
late afternoon. A dry slot to system coupled with the
downsloping may curtail the pcpn in the Hudson River Valley
allowing the thermal profiles for rain briefly especially south
and east of Albany. However, strong QG lift will continue
north/northwest to the deepening cyclone for periods of wet
hvy snow to continue west of the Hudson River Valley and over
the northern Berkshires, and southern Green`s. The upslope flow
will shift to the east to northeast with the wave reaching
eastern Long Island. Snowfall rates an inch or two an hour will
continue continue for portions the southern Adirondacks, Mohawk
Valley, eastern Catskills and southern Greens. The precipitation
should turn back over to snow the Hudson River Valley as we
enter the deformation zone to the coastal wave late in the day
into the early evening. The 3-km NAM and HRRR shows potential
intersection with the DGZ once again as it lowers in height
based on the BUFKIT profiles.Heavy wet snow will continue over
the higher terrain. Sharp snowfall accum gradients will persist
in eastern Albany County and this is why it was upgraded to a
warning. We have to monitor western Rensselaer where we have a
and advisory. Southern Washington County should turn back over
to snow late in the day and this is why we increased the snow
amounts to 5-9 inches through the overnight period. Some
locations in the higher terrain may approach 15-20 inches
before nightfall. Highs will only be in the upper 20s to lower
mid 30s over the hills and mtns, and mid and upper 30s in the
valley areas.
Fri night...The coastal low deepens and intensifies to around
990 hPa as it approaches Cape Cod and moves east to northeast of
the Gulf of Maine. The forecast area will be in the mid and
upper level deformation zone and most, if not all the pcpn will
change back over to snow. Widespread snow accums are possible.
The snow should continue to pile up over the higher terrain, and
this is where the Taconics could see heavy snow. We were not
confident western Dutchess county would reach advisory levels or
southern Litchfield County where we have only 1-3 or 1-4". Snow
rates may exceed three quarters of an inch to an inch an hour
at times again. Some locations in the eastern Catskills,
southern Adirondacks, and southern Greens, and northern
Berkshires could end up to 18-30". Some downed tree limbs or
power outages may occur with the heaviest wet snow. Locations in
the western- central Mohawk valley 10-20" and portions of the
Lake George Region, and the northern Capital Region 7-15" or
8-16". Albany is tricky but a storm total 5-9" is possible with
greater totals to the west. We will have to monitor if a
pivoting snow band forms near western New England, as the H700
low closes off. Stay tuned to updates with this challenging
storm system., Lows fall back into the 20s to lower 30s with the
winds increasing from the west to northwest. Total storm liquid
equivalent will range from 1.25-2.50" with this event.
Saturday-Saturday Night...Lingering west-northwest upslope
snowfall may persist over the western Adirondacks, and southern
Greens early Saturday morning for some light snow accumulations.
The next issue will be lake effect snowfall developing downwind
of Lake Ontario Saturday afternoon into Saturday night. Some
light to moderate snow accums will be possible for the western
Adirondacks, otherwise it will be cold and mainly dry across
most of the forecast area. We may need headlines for the western
Adirondacks for the lake effect later depending on the inland
event of the banding and amounts. Highs Saturday will run below
a little below normal with mid and upper 30s in the lower
elevations and upper 20s to lower 30s over the mtns. Lows Sat
night in the teens and lower 20s.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Following our Friday - Saturday winter storm, expect a long duration
lake effect snow event for the western Adirondacks with some upslope
snow showers for southern VT and the northern Taconics Sunday
through Monday. In fact, a multi-lake connection may develop
resulting in enhanced banding and snowfall rates Sunday night into
Monday. After a brief dry break on Tuesday, an arctic boundary may
lead snow showers or even snow squalls on Wednesday. Read on for
details.
The main highlight of the Sunday to Monday period will be lake
effect snow showers the will develop downstream of Lake Ontario.
This will occur in response to the closed parent cyclone from the
Upper Midwest tracking eastward over the Great Lakes which results
in persistent cold air advection over the lake. Initial west-
southwesterly flow will direct the lake effect band over northern
Herkimer County early on Sunday but as the parent cyclone weakens
and broadens, flow should back to the west and enhance the cold air
advection over the long fetch of the lake. This will enhance the
lake effect banding and help direct the band further inland and more
into central Herkimer County. Westerly flow continues into Sunday
night and even shifts to the west-northwest as the parent cyclone
tracks into the North Country. Guidance suggests this wind regime
may invoke a multi-lake connection as the west-northwest flow and
cold air advection tracks over the Georgian Bay and Lake Ontario.
This would again enhance snowfall rates and the intensity of the
lake effect band. Additional shortwaves could rotate around the
parent cyclone heading into Monday which could lead to a wind shift
to the northwest and therefore redirect the lake effect band further
south, approaching the Mohawk Valley by Monday evening.
High pressure finally builds into the Northeast by Tuesday which
should provide enough subsidence to end the lake effect snow. Expect
dry conditions for the entire area Tuesday before an arctic cold
front tracks eastward into our region on Wednesday. The sharp
thermal gradient and influx of arctic air combined with increasing
vorticity advection from the incoming shortwave could lead to snow
showers or even snow squalls. We will keep an eye on the potential
for snow squalls and message accordingly if confidence increases.
Temperatures this weekend and into early next week will be
seasonably chilly with daytime highs in the low to mid 30s with
overnight lows in the teens and 20s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
MVFR ceilings at POU and PSF and VFR ceilings at ALB and GFL will
persist tonight ahead of the main area of snow that will
overspread the region from 01 UTC to 04 UTC. While marginal
temperatures at POU may support rain initially, ALB, GFL and PSF
will likely begin as snow given colder temperatures. Snow will
result in MVFR visibility and IFR ceilings with periods of IFR
visibility possible overnight during times of moderate snowfall.
Best window of opportunity for moderate snowfall is 06 to 11
UTC.
During the day tomorrow, IFR ceilings will persist at PSF while
GFL, ALB and POU could improve to MVFR if precipitation turns
lighter, mainly after 15 UTC until 20 - 22 UTC. As precip turns
lighter, snow may mix with or even turn to plain rain. During
any mix or rain, visibilities should improve to MVFR.
After 21-22 UTC, colder air infiltrates the area resulting in a
changeover back to snow and may become moderate at times. This
would likely result in a return to IFR visibility and ceilings.
Northeast to easterly winds tonight will be sustained near
5-10kts with strongest winds at PSF. LLWS shear is possible at
POU as the winds at 2kft strengthens to 40kts. PSF turns breezy
tomorrow with sustained easterly winds rising to 10 - 18kts
with gusts up to 25kts. The other terminal will observe weaker
northeasterly winds ranging 5 - 9kts.
Outlook...
Friday Night: High Operational Impact. Definite SN.
Saturday: Moderate Operational Impact. Chance of SHSN.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: No Operational Impact. NO SIG WX.
Sunday Night: No Operational Impact. NO SIG WX.
Monday: Low Operational Impact. Breezy. Slight Chance of SHSN.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: No Operational Impact. NO SIG WX.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...Winter Storm Warning until 10 AM EST Saturday for CTZ001.
NY...Winter Storm Warning until 10 AM EST Saturday for NYZ032-033-
038>043-047>052-054-058-061-063-082>084.
Winter Weather Advisory until 7 AM EST Saturday for NYZ053-059-
060-064-066.
MA...Winter Storm Warning until 10 AM EST Saturday for MAZ001-025.
VT...Winter Storm Warning until 10 AM EST Saturday for VTZ013>015.
&&
$$
SYNOPSIS...Frugis/Gant/Wasula
NEAR TERM...NAS/Wasula
SHORT TERM...Wasula
LONG TERM...Speciale
AVIATION...Speciale
Area Forecast Discussion
National Weather Service Boston/Norton MA
1056 PM EST Thu Dec 15 2022
.SYNOPSIS...
Coastal low pressure moves north toward southern New England
tonight with rain and high-elevation snow through Friday.
Coastal low pressure then shifts eastward into Saturday
afternoon with improving conditions. Dry and blustery conditions
Sunday through Tuesday with near to below normal temperatures
in this period. While there is greater uncertainty in the
weather pattern for mid next week, below normal temperatures
appear favored.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
1030 PM Update...
Have increased precipitation chances especially across eastern
areas where ocean effect rain showers are a bit more widespread
than previous forecast indicated. Did lower temps a bit toward
the HREF/HRRR guidance across the higher terrain based on
observations. Rest of the forecast is on track.
630 PM Update:
Current regional radar mosaic shows some 15-25 dbZ radar
returns associated with warm-frontal precip shield but llvl dry
air still holding precip at bay; still have to go back to POU
before any precip is being reported specific to the approaching
synoptic-scale system. ENE maritime flow is however producing
spotty light showers or drizzle across NE thru E`rn MA. RAP-
based model soundings suggest column not saturating up enough
for another couple hrs; incorporated the bias-corrected HRRR for
PoP to slow timing down. This resulted in no appreciable change
to rain or elevational-band-dependent snow forecast. Expect
negligible hourly temperature changes with any cooling offset by
increasing moisture and warm thermal advection. Otherwise no
significant change needed attm.
Previous discussion:
Highlights...
* Winter Storm Warning and Winter Weather Advisory are in effect as
of 7pm Thursday for east slopes of the Berkshires and northern
Worcester Hills respectively.
Surface low over the Carolinas moves north over the waters of the
Mid-Atlantic, before reaching southern New England on late Friday
morning. Showers expected overnight as a surface trough extends
northward from the low into the northeast. The latest regional radar
composite have showers as far northeast as the PA-NJ border with NY.
While there are echos further northeast, there remains a layer of
drier air near the surface with a T/Td of 6 and 8 degrees.
Showers should begin to overspread southern New England between 03z
and 06z as the atmosphere saturates. The biggest question, where
will the snow accumulate? The greatest confidence for significant
snow likely to accumulate for those areas at and above 1,000 feet,
places such as Berkshires and northern Worcester Hills. Elsewhere
there will be a cold steady rain.
925mb and 850mb flow is out of the east, which will keep the much of
southern New England relatively mild for mid December. But, it is
the easterly flow that will enhance snowfall, especially the east
slopes of the Berkshires. Between 06z and 10z, HREF highlights the
Berkshires with a 30 to 50 percent chance of snowfall rates
exceeding 1 inch per hour! This will make any travel difficult. Snow
to liquid ratio is low given the setup, generally 7-9:1.
Winter Storm Warning and Winter Weather Advisory are in effect as
of 7pm Thursday for east slopes of the Berkshires and northern
Worcester Hills respectively.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Highlights
* Heavy wet snow continues for western MA and northern Worcester
Hills, highest snowfall expected in far western MA.
* Wind Advisory for gusty easterly winds for eastern MA and
southern RI.
Friday:
Wind driven rain and heavy wet snow are the primary threats for
Friday as a surface low strengthens off the coast of southern New
England. First, lets discuss the snow. HREF continues to show a
signal for heavy snowfall across the Berkshires, with 10 to 40
percent chance for snowfall rates exceeding 1 inch per hour between
15z and 20s. Winds are blowing at 925mb and 850mb enhancing the
upslope potential, giving 12 to 18 inches of heavy wet snow across
the Berkshires with locally higher amounts of 18+ inches for the
northern Berkshires along the Vermont border (ending 18z Saturday).
Given the SLR are 7-9:1 this will be heavy, power outages are
possible. Lesser snow amounts are expected for the northern hills of
Worcester county as there will be warmer air at the surface to
contend with. Snowfall for much of Worcester County comes late
Friday night and early Saturday morning as the storm exits the
region.
As for the winds, the 925mb/850mb low is centered just off the
south coast with winds aloft 40 to 50 knots. Not out of the
question there are gusts for the immediate east coast/south
coast of MA and southern RI (including the islands), gusts
between 45 to 50 mph are likely.
Temperatures remain well above freezing in all of the metros; BOS,
PVD, BDL, and ORH. This will limit any snowfall accumulations during
the day, but some light snow is likely Friday night as the storm
pulls east and exits the region.
Friday Night:
Ongoing 998 mb cyclone SE of Long Island early Fri evening will
continue to slowly meander NE through Cape Cod and move more slowly
NNE just east of Mass Bay by Sat AM.
Ongoing higher-elevation accumulating wet snow will continue across
the Berkshires, though as colder air advection cools the column,
another period of lighter-accumulating wet snow will resume across
the hills in northern Worcester County overnight. An additional 2 to
5 inches of new snow anticipated across the east slopes of the
Berkshires through 12z Sat, with up to a couple inches in the same
timeframe for portions of northern Worcester and northwest Middlesex
Counties. This colder air advection to gradually transition plain
rain over to a mix of rain and wet snow in the lower elevations in
the interior part of MA, CT and western RI (west of I-495/I-95),
with only slushy coatings. Light rains to turn lighter/more
intermittent across southeastern RI/southeast MA as coastal low
moves NE and dryslot moves in.
East-coastal strong E to NE wind gusts to have eased across most of
eastern and southeast MA, but will have continued 35 to 45 mph NE
gusts across Boston northward to the North Shore. Wind gusts across
the Islands will however begin to increase again from the WNW as
coastal low moves north of Cape Cod to around 35 to 40 mph.
Gradual/slow fall in temps given cloud cover and winds in low-mid
30s interior MA and CT and upper 30s-mid 40s eastern MA and RI.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Highlights...
* Precip ends Sat AM as coastal low pulls away into the Atlc waters.
* Drier with near to below normal temps Sun thru Tues.
* More uncertainty in weather pattern beyond Wed but below normal
temps favored for mid-late week.
Details:
Slow-moving low pressure then pulls away into the eastern waters
with better cold air advection on NW winds during the day on Sat.
Minor/additional wrap-around moisture will continue to impact the
hilly terrain in the Berkshires and northern hills in Worcester
County and into northeast MA. Additional snow accumulation in the
Berks and northern Worcester County a coating to an inch thru Sat
morning. NW winds will increase to around 10 to 20 mph with gusts 20
to 30 mph. Some sun will bring highs to the mid 30s to mid 40s but
the winds will make it feel cooler than that.
Given active weather in the near and short term periods, didn`t
spend much time looking at the extended forecast period. Tendency
toward seasonal to below avg temps in a generally dry period Sat
night thru Tues.
Forecast guidance then differs beyond Wed regarding a possible cold
frontal passage around Wed - GFS is quite robust showing modified
Arctic air behind this front but given a systemic GFS cold bias in
the extended range the magnitude of the colder air it is depicting
is in some question. However the international guidance shows
cooling temps into midweek so temperatures likely will continue to
downturn into midweek. Even larger uncertainty in ensembles and 12z
guidance regarding the late-week weather pattern/possible
storminess; something we`ll be certainly closely watching but
solution spread remains way too large to delineate any specifics at
this point. Thus opted for a broad brushed chance PoP beyond Wed
night.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
00Z TAF Update:
Tonight: High confidence in trends, moderate on exact timing.
MVFR ceilings generally common as steadier warm-frontal precip
advances 03-05z BAF-BDL and 06-10z ORH-PVD westward to BOS.
Advance of precip should bring about lowering and onset of IFR
type ceilings. Generally 4-6 SM -RA/RA for most TAFs but may mix
with SN at BAF (BAF runways mainly wet). ENE to E winds at
10-20 kts with gusts of 20-40 kts. Expect the highest gusts
across the south coast and higher terrain.
Friday...Moderate confidence.
IFR with localized LIFR. Elevational snow continues with a cold
rain elsewhere. Winds out of the E/ENE at 15-25 kts and gusts of
25-45 kts. Should see the highest gusts across the coastal
plain.
Saturday...Moderate confidence. MVFR/IFR conditions possible.
Windy with gusts up to 30 kt. Chance RA, chance SN.
KBOS Terminal...High confidence.
KBDL Terminal...High confidence.
Outlook /Saturday through Tuesday/...
Sunday through Tuesday Night: VFR. Breezy.
Wednesday: Breezy.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
330 PM Update:
Overall high confidence.
Increasing easterly gusts and building and increasingly rough seas
will be the trend into the gale level tonight through much of Fri.
Gale Warnings remain in effect for all waters through Fri evening
(00z Sat), then become more confined to the eastern and northeast
waters thru Sat AM. Offshore seas build to 8-11 ft by early Fri AM
and continue to build to 11-15 ft offshore.
Fri evening, while winds should briefly drop into the SCA level as
directions turn from NE to NW, increasing gusts into the Gale level
may develop into the Fri overnight hrs/early Sat period into the
southern waters. While not reflected in the forecast yet given
active gale warnings, may need to consider gale headlines on
portions of the southern waters starting overnight Fri nite/early
Sat.
Outlook /Saturday through Tuesday/...
Sunday: Winds less than 25 kt. Seas up to 5 ft.
Sunday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Rough seas up to 8 ft.
Monday: Strong winds with gusts up to 25 kt. Rough seas up to
9 ft.
Monday Night: Moderate risk for Small Craft Advisory winds with
gusts up to 25 kt. Seas up to 5 ft.
Tuesday: Low risk for Small Craft Advisory winds with gusts up
to 20 kt. Local rough seas.
Tuesday Night: Winds less than 25 kt. Seas up to 5 ft.
Wednesday: Low risk for Small Craft Advisory winds with gusts
up to 20 kt. Seas up to 5 ft.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...Winter Storm Warning until 7 AM EST Saturday for MAZ002-008-
009.
Winter Weather Advisory until 7 AM EST Saturday for MAZ003-004.
Wind Advisory from 7 AM to 10 PM EST Friday for MAZ007-014>016-
019-021-022.
Wind Advisory from 4 AM to 7 PM EST Friday for MAZ020-023-024.
RI...Wind Advisory from 4 AM to 7 PM EST Friday for RIZ005>008.
MARINE...Gale Warning from 4 AM Friday to 4 AM EST Saturday for
ANZ230>232-250-251-254.
Gale Warning until 10 PM EST Friday for ANZ233>235-237-255-256.
Gale Warning until 7 PM EST Friday for ANZ236.
&&
$$
SYNOPSIS...Loconto/Gaucher
NEAR TERM...BL/Loconto/Gaucher
SHORT TERM...Loconto/Gaucher
LONG TERM...Loconto
AVIATION...Loconto/Gaucher
MARINE...Loconto/Gaucher
Area Forecast Discussion
National Weather Service Cleveland OH
934 PM EST Thu Dec 15 2022
.SYNOPSIS... Low pressure over the Upper Midwest gradually
shifts eastward through Saturday with a surface trough linger
across the central Great Lakes. High pressure builds overhead
early next week.
&&
.NEAR TERM /THROUGH FRIDAY NIGHT/...
930 pm update...
We updated the hourly POPs through 12z in the morning to better
reflect with the latest trends with the HRRR and current radar.
The hourly POPs were adjusted slightly lower for the overnight
across far NEOH and NWPA.
630 pm update...
The near term forecast tonight into tomorrow looks on track with
no significant or impactful changes needed at this time. We are
seeing the occluded front show up fairly well on the radar this
evening near CLE due southward with a very thin line of heavier
showers. This front will continue to track eastward and a
decrease in POPs will follow behind this passage.
Previous discussion...
Occluded frontal boundary dissipating as it drifts eastward
this evening. Much of the region near and east of the Mid-Ohio
region eastward into western PA should see variable amounts of
drizzle through the evening. There are a couple pieces of better
lift that move across the region so a few passing showers are
anticipated. During the overnight hours we may start to see some
snow mix in with the drizzle and passing showers. No
accumulations are anticipated.
Winds have decreased with the weakening surface pressure
gradient across NW PA. Gusts may still reach 30 knots or so but
are not expected to increase so we will cancel the Wind Advisory
a couple hours early.
Cooler air gradually drifts into the area Friday with highs
dipping back into the 30`s. The upper level low remains in the
vicinity of the CWA so there will be some general weak lift.
There could be just enough jet energy to enhance this lift that
moves overhead with a few passing rain/snow showers possible
Friday afternoon. No snow accumulation is expected.
Lake effect snow develops over the lake into NY Friday night. We
will need to monitor it closely but it looks like it remains
offshore through the night. However there still are chances of
snow with light accumulations possible near the lakeshore of
Erie County, PA. Lows dip into the 20`s at most locations.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Upper level closed low over the Central Great Lakes will move to the
eastern Great Lakes through Saturday night before continuing east
towards Quebec/New England. The airmass will be cold enough with
sufficient moisture for lake effect snow. However, flow through the
column will be primarily out of the southwest on Saturday with lake
effect snow bands focused out over Lake Erie into western New York.
Despite heavier lake effect snow bands being focused primarily
offshore, models are in fairly good agreement that mid-level
moisture will rotate eastward into the forecast area through
the afternoon. Given the deeper moisture and broad cyclonic
flow, have added a chance of snow showers to much of the
forecast area. Most areas away from Lake Erie will see little to
no accumulation with high temperatures in the lower 30s.
As the upper level low shifts eastward on Saturday night, the trough
over Lake Erie will shift closer to shore. Some snow shower activity
is expected to return to lakeshore areas Saturday night into Sunday
but moisture depth and inversion heights will also be on the
decrease by Sunday. Expecting sufficient depth to remain for snow
showers with higher confidence across Erie County PA. At this point
accumulations looks to be light to moderate for Erie County with
lesser amounts elsewhere although band placement will need to be
monitored over the weekend.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
A ridge of high pressure will expand eastward across the Ohio Valley
on Monday which should back low level flow to southerly and push any
lingering lake effect snow showers over Lake Erie. The second
half of Monday and Monday night should be dry before the next
upper level trough approaches for mid-week.
Models indicate low pressure will move through the Central Great
Lakes Tuesday evening, pulling a strong cold front eastward across
the area into Wednesday. Some differences remain among the models as
to when the true arctic airmass is expected to arrive. Could see
this front trending slower but models are in agreement that a
longwave trough and below normal airmass will set up across the
eastern United States towards the end of the week. Confidence
is high in below normal temperatures with lower confidence in
precipitation potential. The last two cycles of the ECMWF have
been showing synoptic snow possible on Thursday while the 12Z
GFS favors a system tracking up the East Coast. Although we will
have to monitor model trends as we watch this potential storm
track, lake effect snows will become likely as an arctic
airmass arrives. Timing and favored areas for possible lake
effect snows will also be monitored into next week.
&&
.AVIATION /00Z Friday THROUGH Tuesday/...
Overall MVFR to lower end MVFR ceilings will be expected for
the duration of the next 24 hours for TAFs. There are some
pockets of IFR ceilings where are impacting CLE, CAK, and YNG
through about 4z this evening. Those ceilings should stabilize
around 1500 to 2000 feet later tonight. Scattered light rain
showers and light drizzle continue to move across NEOH and NWPA.
We have the mention of VCSH for those brief showers. Winds
will become more from the southwest in the wake of the occluded
frontal boundary crossing the area. Still seeing localized stronger
gusts up to 25 knots from the southeast at KERI through about
3z. South to southwest winds decrease to 5 to 12 knots
overnight and remain that way into Friday.
Outlook...Non-VFR possible with periods of snow Saturday through
Monday, mainly across NE OH into NW PA.
&&
.MARINE...
Winds will decrease into tonight as the pressure gradient weakens
and a cold front sweeps east across Lake Erie. A Small Craft
Advisory will remain in effect for locations east of Willowick until
7 PM and the expiration time appears to be on track. Winds will veer
to southwesterly overnight and be in the 15-20 knot range through
Friday. Winds are expected to increase Friday night as surface low
pressure moves from the Upper Midwest across the Upper Great Lakes.
A Small Craft Advisory will likely be needed again for areas east of
Avon as this low pressure system makes slow progress towards Quebec
and colder air arrives across Lake Erie. The potential for Small
Craft conditions exists west of Avon but is lower.
Marine conditions are expected to improve by Monday as a ridge of
high pressure builds east through the Ohio Valley. Low pressure will
pass north of Lake Erie on Tuesday pulling a strong cold front east
across Lake Erie into Wednesday.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...MM
NEAR TERM...Griffin/MM
SHORT TERM...KEC
LONG TERM...KEC
AVIATION...Griffin
MARINE...KEC
Area Forecast Discussion
National Weather Service Gray ME
937 PM EST Thu Dec 15 2022
.SYNOPSIS...
Low pressure developing off the Mid Atlantic moves along the New
England coast to bring the first big winter storm of the
season. While temperatures falling to around freezing tonight,
precipitation should fall hard enough to result in mostly snow
across the area. Mixing is expected to be an issue across
southeastern New Hampshire and coastal western Maine. Across the
interior, snowfall of 6 inches or more is expected, with lighter
amounts due to mixing along the coast. The storm will linger and
continue to bring periods of snow to parts of the forecast area
through late Saturday night. Building high pressure brings
quieter weather for most of the workweek, and then another
coastal storm is possible around the end of next week.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
935 PM Update...
Latest update was to increase pops for portions of central
Maine as a few precipitation reports are coming in related to
the low level maritime moisture within the northeast flow. This
precipitation remains very light.
730 PM Update...
Ocean effect rain showers continue to cross portions of far
southwesternmost Maine and southeast this evening. Just received
a spotter report from the Dover, Rochester area where the
precipitation was mixing with snow when the shower increased in
intensity.
Mostly rain with some snow shower activity will continue across
this region while we await the synoptically driven precipitation
situated over eastern New York State. This precipitation will
continue to have a difficult time making fast progress to the
northeast as it encounters a very dry atmosphere over northern
New England. The dry layer is evident in the 00Z GYX sounding
which is present from about H8 and up. This dry air will also
act to change some areas that are receiving rain, back to snow
later tonight due to evaporational cooling as noted by the
latest HRRR.
Made only minor modifications to the near term portion of the
forecast. Adjusted temperatures and dew points based on current
observations.
Prev Disc...
High Impact Weather Potential: Snow overspreads interior New
Hampshire after midnight with slick travel developing by
daybreak.
Pattern: Occluded and vertically stacked low is centered over
Minnesota this afternoon with an occluded front arcing south and
east across the Great Lakes...and the south and east into the Mid
Atlantic with a pressure weakness over eastern VA/NC indicating the
beginning of low pressure that will bring the first widespread
winter storm to our region beginning late tonight. Precipitation
band in the warm advection regime and along the moist southeasterly
Jet at H8 is slowly advancing north and east with the high over low
blocking pattern downstream over the Canadian maritimes slowly
pushing east. Primary forecast concern will be on the arrival of
this precipitation shield and what PTYPE it will take when it
arrives.
Through this Evening: Stratocu has enveloped most of the forecast
area with top down saturation expected to continue to increase
overall cloud cover. It will remain fairly mild through 7pm with
temperatures around 30 in the mountains with mid to even upper
30s common to the south.
Tonight: +DPVA arrives overnight with top down saturation
allowing upstream band of precipitation to arrive after
midnight. Moist easterly flow ahead of this feature will likely
allow for a few rain/snow showers ahead of the main band which
is just an expansion of what is already happening over the Gulf
of Maine. SE NH should begin as rain with snow from EEN to CON
and north with an inch or two possible by daybreak Friday.
Further east across western Maine...precipitation of any
significance will hold off until after daybreak.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
SIGNIFICANT AND PROLONGED WINTER STORM TO BRING SIGNIFICANT
SNOW FOR MANY LOCATIONS..
High Impact Weather Potential:
* Heavy Snow for all but far SE NH and the coast of ME from
Portland South. Inland...totals well over one foot are
possible...particularly for locations at elevation.
* Snow will be heavy and wet just inland from the changeover line
with the potential for power outages.
* Wind Gusts will approach advisory criteria in the somewhat
warmer air from Portland south to Seacoast NH.
Pattern: Surface low track has trended further north over the
past 24 hours but also a bit deeper...which helps hold the cold
air in north of it/s eventual track. Consensus track moves from
the SE Jersey coast around daybreak Friday north and east across
southeastern MA Friday night while slowly deepening...with the
low hesitating for a time east of Cape Ann before pushing east
towards the Nova Scotia. H7 low tracks from southern New England
ENE into Nova Scotia.
Model Preferences: There is good agreement on the overall surface
low evolution but have followed the EC/NAM3km/HRRR track more
closely. Looking at upstream observations...the HRRR has been too
warm with temperatures in the precipitation region and have tended
to follow more closely the NAM 2m temperatures/dewpoints which has
it/s biggest implications for the Maine coast...which as the
deepening low arrives Friday afternoon/evening precipitation rates
and ENE flow should bring the snow line rather close to the coast.
PTYPE evolution:
* Rain from ASH/MHT to the NH Seacoast through Friday night
with a possible changeover towards daybreak Saturday.
* Favoring all snow north of a EEN-CON-GYX-LEW-AUG line.
* Between this line and the coast...precipitation will likely start
as rain or a rain snow mix...and then transition to more snow by
Friday late afternoon /after sunset/ as heavier precipitation
rates arrive with snow continuing Friday night.
QPF: What the event lacks in strong deepening of the surface low it
makes up for in longevity with the eastward progression hesitating
as the H5 low cuts off before the surface low then pulls east. The
result is around 1" near the Canadian border with amounts increasing
to around or a bit above 2" along the coast near where any mesoscale
banding associated with the surface low will pivot before pulling
east.
Snowfall Rates: Without a rapidly deepening low...snowfall rates
generally look to be moderate with HREF probs pretty meager on a
signal for much above 1"/hr...centered on late Friday afternoon and
the first half of Friday night. Light-moderate rates will likely be
in place to begin the day Saturday...tapering off with time.
Honestly...this is the biggest concern for areas with marginal
temperatures seeing enough snow to warrant warning-headlines.
Winds: While northeasterly winds will be gusty late Friday and
Friday night...best threat for winds over 40 mph will be coastal
York and Rockingham were mixed layer is deepest. Confidence not
high enough to issue advisories here with this package...and
will let the overnight shift have another look. Winds where
precipitation remains mostly snow will likely remain below 30
mph precluding significant additional wind-related impacts.
Saturday-Saturday night: Expect robust snowfall to be ongoing across
much of the area daybreak Saturday with rates starting to decrease
in the afternoon. Daytime snowfall on Saturday will range from an
inch or less over southern NH to as much as 4-6 inches over the
western ME mountains.
Headlines: Have issued a string of advisories for most of the
coastal zones except coastal York/Rockingham counties where very
little snow is expected. In the advisory area. For the advisory
in NH...amounts are a bit on the low side...but with significant
variation throughout the zones. From Portland north and
east...can/t rule out these zones eventually needing
warnings...but precipitation rates remain a bit questionable and
do not have high enough confidence that we/ll see 6" amounts in
this area. Further inland...8-14+ is looking likely with areas
over 1000 feet likely to push the high end of this envelope and
of course some mountain spots even higher. Biggest impact
concern will be along the SEern edge of the warning where
snowfall will be heavy and wet /ratios 5-8:1/ which...after
accumulating 4-5" will be sufficient to start taking down tree
limbs and causing power outages.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Overview...
Light snow is likely to be ongoing Sunday morning across
eastern and northern zones as this first storm system only
gradually moves eastward. Breezy conditions are likely Monday
through Wednesday as the system remains across the Canadian
Maritimes, and high pressure gradually builds in from the west.
With this flow pattern, seasonable temps are expected most of
the week. A weak disturbance brings an increased chance of snow
showers on Wednesday across northern areas. By late in the week,
there is increasing potential that another large storm system
could impact New England, with rain, snow, and wind possible.
Details...
The center of the low from the upcoming storm is expected to be
near Nova Scotia by Sunday, but an elongated trough and ample
moisture is likely to keep light snow ongoing across eastern
areas and the mountains. Accumulations would likely be light on
Sunday itself, and they would only be on top of the higher
totals form the previous couple of days. Southern areas may see
a few snow showers through the day, but otherwise mainly cloudy
skies with highs in the 30s are expected.
By Sunday night the system should be pulling away, with upslope
snow showers gradually lessening in coverage into Monday.
Northwesterly flow will bring some breezy conditions on Monday
and Tuesday, but generally brighter conditions with seasonable
temperatures are expected outside of the mountains. Scattered
northwesterly upslope snow showers are possible into Tuesday.
Another round of snow showers are possible late Tuesday night
and Wednesday across northern areas as a shortwave passes
through the area in the northwesterly flow pattern.
Despite the persistent northwesterly flow, the ongoing blocking
pattern across Greenland will continue to feed mild maritime
air into the arctic air masses as they move southeastward into
the area, resulting in an airmass with near normal temperatures.
By Thursday and Thursday night, the ridge axis likely makes its
closest pass to New England and offers the best chance for
colder nighttime temperatures. While not overly impressive on
their own, they do represent the antecedent airmass ahead of
the next storm system.
Another storm system has the potential to impact the area by
the end of next week. While still roughly seven days away, there
is a higher than usual level of confidence that the system will
affect New England sometime in the Thursday night to Saturday
timeframe. There is strong agreement among the global models on
this, and there has been a relatively high level of run to run
consistency with the system as well. What remains to be seen, of
course, is what the track of this system will be. Both rain and
snow are possible with this system, with the development and
track of a secondary coastal low the main driver of this. Models
are showing anything between and wind driven rain to all snow,
so at this point in time we will continue to monitor the trends
over the next few days for a better picture of the impacts.
One factor with the storm late next week is that astronomical
will be at their peak for the month, with any kind of onshore
flow likely leading to impacts. These impacts will also be
determined by the track and timing of the system.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...
Significant impacts to aviation interests are expected to develop
through the next day or so, lasting through Friday and much of
Saturday as a winter storm passes just offshore. Broken down by
aspect...
CEILINGS...MVFR CIGS are already filling in this afternoon in
northeast flow. This trend will continue through the overnight with
CIGS lowering to IFR in southern zones by around daybreak...perhaps
a bit sooner with at KPWM, and perhaps for a brief time at KMHT/KCON
as light showers develop. IFR CIGS are forecast to hold off until
the mid-morning hours further north into KAUG, meanwhile over at
KHIE mountains will likely block lower ceilings from filling in
until steadier precipitation arrives... with MVFR CIGs developing by
mid-morning, and IFR holding off until winds turn northerly on
Saturday. IFR CIGs, at times LIFR in heavier precipitation, prevails
into Saturday with modest improvement to MVFR for southern interior
terminals by the end of the day, VFR for most places by Sunday
morning... though there is more disagreement heading east with how
quickly conditions will clear with this slow moving system. KHIE
meanwhile will continue to experience low ceilings as flow
transitions to the upslope variety into Saturday.
PRECIPITATION/VSBY...The rain/snow line continues to be the most
challenging portion of the forecast, especially in the vicinity of
our busier terminals along the coast and in the southern interior.
Before the primary swath of stratiform precipitation moves in... A
few preceding light showers may develop and provide brief VSBY
restrictions, mostly from SN where IFR is more likely at KPWM/KCON
versus VFR/MVFR in RA at KMHT/KPSM after midnight tonight. Steadier
SN/RA arrives in the few hours surrounding daybreak on Friday with
IFR SN for all sites except for RA at KMHT/KPSM. KMHT and KPWM
exhibit the highest degree of uncertainty WRT precip type through
the period... with the current forecast depicting a change to rain
at KPWM by around noon and riding the RA/SN line until Saturday
morning when SN is expected. KMHT sees the transition from RA to SN
late Friday night/early Saturday. Mainly light snow is expected
through Saturday, tapering off from west to east through the day...
but hanging on further east into Saturday night.
WINDS/LLWS... Light ENErly winds today will strengthen through
tomorrow, then turn northerly early Saturday morning... and
eventually northwesterly late Saturday and overnight. While the PGF
alone will make for steady winds between 10-20 kts for most
places... strongest at the coast... wind gusts will be fairly
limited over most of the interior, where prolonged easterly LLWS is
more likely to occur, starting between midnight and dawn for
KMHT/KCON/KLEB/KHIE, and lasting through Friday into Friday night
before the LLJ responsible starts to pull away to the east. At the
coast... wind gusts 35-40 kts will center on the Fri aftn and
evening period, with a more brief period of LLWS as the core of the
LLJ comes overhead. Wind gusts will very gradually diminish Friday
night through Saturday, from east-to-west, falling below 20 kts over
NH during the day and then over ME by the evening.
Long Term...Light snow likely brings continued restrictions
through midday Sunday across northern and eastern terminals,
with MVFR to VFR ceilings likely elsewhere. Conditions gradually
improve Sunday night, with mainly VFR to MVFR at times on
Monday. HIE is likely to see more MVFR conditions Monday and
Tuesday, along with scattered snow showers. Snow showers are
possible on Wednesday across northern terminals, with improving
conditions Wednesday night and Thursday. Rain or snow is then
likely Thursday night and Friday.
&&
.MARINE...
Short Term...While a few gusts to storm force are possible over
the outer waters...confidence in their longevity and location is
not high enough to warrant a storm warning. Therefore...have
transitioned to gales everywhere for the upcoming low pressure
system...which will pass through the Gulf of Maine on Saturday
with winds shifting northwesterly and slowly subsiding Saturday
night.
Long Term...SCA conditions continue on Sunday through Monday
with northwesterly winds and residual elevated seas, and then
gradually lower on Tuesday as northwesterly flow eases. High
pressure gradually builds in through midweek.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Winter Storm Warning from 10 AM Friday to midnight EST
Saturday night for MEZ007>009-012>014-018>022-033.
Winter Weather Advisory from 10 AM Friday to midnight EST
Saturday night for MEZ024>028.
NH...Winter Storm Warning from 10 AM Friday to midnight EST
Saturday night for NHZ001-002-004.
Winter Storm Warning from 1 AM Friday to 7 PM EST Saturday for
NHZ003-005>009-011-015.
Winter Weather Advisory from 1 AM Friday to 7 PM EST Saturday
for NHZ010-012-013.
MARINE...Gale Warning from 4 AM Friday to 4 PM EST Saturday for
ANZ150>154.
&&
$$
NEAR/SHORT TERM...Cannon
LONG TERM...Clair
Area Forecast Discussion
National Weather Service Indianapolis IN
858 PM EST Thu Dec 15 2022
.Forecast Update...
Issued at 857 PM EST Thu Dec 15 2022
Radar trends suggest the light snow showers will be east of
Interstate 65 shortly after 9 pm and east of central Indiana after
10 pm as upper wave around the base of southern Minnesota low ejects
northeast across southern lower Michigan. Meanwhile, IR loop was
showing a few breaks in the stratus were moving into the lower
Wabash Valley, however stratus should mostly stay thick per upstream
IR and moisture trapped beneath a temperature inversion around 4K
feet per HRRR BUFKIT. This should keep temperatures from falling any
lower than the upper 20s overnight.
&&
.Short Term...(This evening through Friday)
Issued at 253 PM EST Thu Dec 15 2022
* Cooler temperatures
* Scattered snow showers and flurries today and tomorrow
* Breezy at times
Rest of Today
Clouds have thickened across the region today, and will likely stick
around through the short term thanks to the cool unstable air mass
overhead. Enough instability may be realized today to generate a few
snow showers or flurries. A vort max rotating around a big closed
low to our north will provide enhanced lift to further aid in precip
generation. Latest ACARS soundings out of IND show generally sub-
freezing temperature profile above 1500 ft. With a fairly dry
surface airmass in place, some of the precip may begin as a few rain
drops. However, temperatures should evaporationally cool to near
freezing which will change precip quickly to snow.
Tonight
Lingering snow showers or flurries will come to an end around
midnight as the vort max lifts northward and instability wanes.
Cloud cover should persist, but a few breaks could open up at times.
Breaks in cloud cover are not currently expected to affect low
temperatures all that much, as winds remain rather brisk during the
overnight around 5-10 kts. Lows in the upper 20s are still in the
forecast due to the robust CAA currently in place.
Friday
Tomorrow may end up being a carbon copy of today, weather-wise. Any
breaks in the stratus deck will quickly fill in, with more snow
showers possible during the late morning and afternoon hours. BUFKIT
soundings show a fairly deep well-mixed layer with some weak
instability. Of the Hi-res models, the HRRR is the most aggressive
regarding instability with 30-50 J/kg CAPE in the lowest 3km of the
atmosphere. While that`s not a lot in normal circumstances, in the
winter it`s something to keep an eye on. Consequently, the HRRR is a
bit more robust with snow shower development.
The deeper mixed layer and instability may be enough to encourage
momentum transfer to the surface after sunrise. Thankfully, the flow
at the top of the PBL isn`t substantial (only around 35 kts within
the 750-850mb layer). Accounting for some momentum loss as it mixes
downward, peak gusts around 25 kts are expected at times. Winds
should die down as the sun begins to set and the atmosphere
stabilizes. Cold temperatures will persist due to the continued CAA,
and highs should top out in the mid-30s.
&&
.Long Term...(Friday night through Thursday)
Issued at 253 PM EST Thu Dec 15 2022
Friday Night Through Saturday.
Occasional flurries and light snow showers will continue Friday
night into Saturday as the aforementioned strong upper level low
pressure system continues to occlude and move into the Great Lakes
region. This slow moving low pressure system will keep a fairly
persistent forecast in place through Saturday with surface flow
generally southwesterly while flow aloft is generally easterly to
somewhat northeasterly.
Areas of weak to moderate vorticity circling around the low will
combine very steep lapse rates near the surface will allow for a
return to flurries and light snow Saturday, especially during the
late morning and early afternoon hours. Flurries will be most
frequent across the northern counties where the upper level forcing
will be stronger.
Sunday Through Tuesday.
The low will finally push away Sunday with zonal to slightly
northwesterly flow aloft during the early work week. Temperatures
will remain near to below normal with the lingering cold air aloft
and lack of southerly surface flow. Another strong upper level
closed low will move through Southern Canada Monday into Tuesday
with the potential for light snow across the area late Tuesday into
Tuesday night. This all will be dependent on the strength of the
upper level low which remains quite uncertain at this time. A
stronger low would lead to stronger northwesterly flow which then
increases the lapse rates and allows for a quick burst of snow.
Wednesday and Thursday.
The pattern will begin to shift going into Wednesday as the next
major weather system approaches, but there remains a significant
amount of uncertainty as to how and when this system will impact the
area. Confidence is increasing that there will be accumulating snow
going into Christmas across portions of the Midwest, but locations,
timing, and amounts remain very uncertain.
There will be a potential for pockets of more significant snow
accumulations, but again it remains very uncertain as to where it
would occur. Models continue to struggle with the development of
this system as it dives into the area from the northwest and how the
late Tuesday system may impact moisture availability. Continue to
monitor the forecast this weekend into early next week as details
begin to become more clear.
&&
.Aviation...(00Z TAF Issuance)
Issued at 532 PM EST Thu Dec 15 2022
Impacts:
- Ceilings will teeter totter in between VFR and MVFR through
the TAF period.
- Scattered light snow showers or flurries possible tonight and
Friday afternoon
- Winds 210-240 degrees 9-13 knots with gusts to 20 plus knots
after 17z
Discussion:
Upper disturbance will lift northeast across the Great Lakes
tonight and more impulses will move northeast across northern
Indiana Saturday afternoon around the base of an upper Wisconsin
low. This will bring fringe VFR and MVFR flying conditions with
visibilities reduced at times in snow showers, mainly Friday
afternoon.
Winds will be southwest and gust to over 20 knots Friday afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...MK
Short Term...Eckhoff
Long Term...White
Aviation...MK
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
711 PM EST Thu Dec 15 2022
...New UPDATE, AVIATION...
.UPDATE...
After a very active day weather wise the atmosphere is stabilizing
and drying out aloft as seen in water vapor imagery. Low level
lift around the surface cold front will continue to produce clouds
and scattered light rain for a few more hours especially in SW FL
areas. Cooler and drier high pressure finally building into the
region this evening for pleasant weather conditions overnight and
Friday. Have updated PoP grids based on radar trends otherwise
forecast on track.
&&
.AVIATION...
(00Z TAFS)
Lingering MVFR stratus clouds and light rain with MVFR vsbys on
post cold front NW-N winds to continue over the terminals through
04-06Z before clearing overnight. Fri a return to N winds and
mostly clear VFR conditions.
&&
.DISCUSSION...
Issued at 220 PM EST Thu Dec 15 2022
A strong cold front continues to push eastward through Florida
through the day. Showers and storms are currently pushing through
the eastern gulf waters and parts of west central and southwest
Florida. The latest radar is showing heavy downpours, frequent
lightning as well as gusty winds over the water and moving ashore as
the squall line moves eastward. A Tornado Watch continues for parts
of west central and southwest Florida through 4 pm this afternoon.
The latest HRRR guidance shows the main line of showers and storms
pushing south and east of Tampa Bay through 3 pm and then pushing
through SW Florida between 2 pm - 6 pm. Showers and storms should
taper off late this evening into the overnight hours with partly
cloudy skies expected on Friday.
The front will be located over southern Florida by early Friday
morning allowing for high pressure to ridge in from the northwest.
Some residual clouds will be possible early Friday morning, but rain-
free conditions are expected and will further clear out by Friday
evening. Pleasant and much cooler weather expected Friday and
Saturday. By late Saturday night, another area of low pressure and
cold front moves across Florida bringing the next chance of showers
and storms. This will be short-lived with clearing conditions by
Sunday afternoon. This will bring another bigger cool down with the
temps dropping 10-15 degrees below average. The coolest day will be
on Sunday with daytime highs expected to top out only in the 50`s
and 60`s and overnight lows on Sunday night dropping into the 30`s
and 40`s. Pleasant and cool weather expected Sunday and Monday
before the next area of low pressure moves through on Tuesday next
week.
&&
.MARINE...
Issued at 220 PM EST Thu Dec 15 2022
Showers and storms continue to push through the eastern gulf waters
and will taper down over the next few hours. The SCA has expired,
but gusty winds will remain around 15-20 knots and seas around 4 to
7 feet through late this evening. Winds shift to the north behind
the front and subside on Friday. Winds will then continue from the
N/NE through the rest of the period with another round of showers
and storms possible Saturday into Sunday.
&&
.FIRE WEATHER...
Issued at 220 PM EST Thu Dec 15 2022
A cold front pushes through the region today producing showers and
storms as well as gusty winds. Some high dispersions today with
gusty winds in the vicinity of the cold front and with showers and
thunderstorms moving through the area. Cooler and drier air moves
into the area behind the front for the rest of the week, but
humidities are expected to remain above critical levels. Dispersions
will be fairly low for Friday, with generally below 30 expected.
Another round of showers and storms possible on Saturday afternoon
into Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 55 70 54 69 / 0 0 0 50
FMY 64 75 60 77 / 40 10 20 40
GIF 53 69 51 68 / 10 0 0 40
SRQ 57 71 54 71 / 10 0 10 50
BKV 47 69 44 68 / 0 0 0 50
SPG 58 68 57 68 / 10 0 10 50
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE/FIRE WEATHER...RDavis
DECISION SUPPORT...Hurt
UPPER AIR/CLIMATE...Close