Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/04/17
Area Forecast Discussion
National Weather Service Buffalo NY
903 PM EST Tue Jan 3 2017
.SYNOPSIS...
A mild airmass with widespread rain will continue into the overnight
hours across the region before a cold front sweeps across the
Eastern Great Lakes...ending the rainfall and ushering in much
colder air. Westerly winds will become strong tomorrow, and lake
effect snow will become organized tomorrow afternoon east of the
lakes, with such snowbands oscillating east of the lakes into the
start of the weekend. Air temperatures will remain below normal
later Wednesday and through the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
Surface analysis shows a broad surface low crossing Western NY late
this evening. This low will consolidate and deepen overnight as it
moves north into Southern Ontario and reaches western Quebec by
Wednesday morning. Regional radars showing the back edge of steady
rain moving through the Finger Lakes and eastern end of Lake Ontario
at mid evening, with the steady rain continuing for several more
hours east of Lake Ontario before tapering off overnight. Farther
west, another area of rain showers will persist across Western NY
through late evening. Upstream radars also show yet another area of
rain in NE Ohio, which the latest high res HRRR guidance brings into
Western NY overnight.
Later tonight behind the cold front temperatures both at the surface
and aloft will drop allowing trailing showers along and behind the
cold front to possibly end as some wet snow across the higher
terrain of the western Southern Tier.
Lake effect snow will begin in earnest through the day Wednesday as
temperatures at 850 hPa drop from around 0C to start the day down to
the negative teens Celsius by the close of Wednesday.
For Lake Erie...initially early Wednesday morning there may be some
lake convergent precipitation...with a mixture of rain/snow and
possibly some sleet through the morning hours...this before the main
dry slot in the lower level arrives. Overall precipitation will be
around a tenth of an inch or lower. This precipitation will diminish
some through the morning as drier air briefly passes across the
lake. Synoptic moisture will soon wrap back around the lake, and
with falling snow dendritic growth zone, we should see a band of
lake effect snow form on a WSW wind through the late morning and
afternoon hours. The westerly wind flow over the shorter fetch of
Lake Erie, combined with a strong wind flow that will limit the
residence time over the lake should limit snow accumulation through
the late Wednesday afternoon hours to just a few inches across Ski
Country, as well as some of the southern southtowns of Buffalo.
For Lake Ontario...temperatures will fall through the day at 850
hPa, steepening the low level lapse rates, and with the dry slot
behind the cold front not likely to reach the lake, we should see a
band of snow develop through the morning hours, oriented along the
long axis of the lake and towards the Tug Hill region. There is
model indication that an upstream connection to the upper lakes will
occur, adding moisture to the lake band and increasing the snowfall
rate. Here, a better organized band of snow is expected than off
Lake Erie, and snowfall amounts of 3 to 5 inches are possible by
late in the day Wednesday across the Tug Hill region.
In addition to the lake snows, there will also be a strong wind
across the region. The surface low this afternoon over the Great
Lakes region will deepen to around 980 mb by Wednesday evening over
southwestern Quebec. This will be around 3SD below normal. While the
surface low will track over the region tonight, with little winds,
the combination of the tightening pressure gradient from the
deepening surface low to our north and building high pressure over
the Plains and Ohio Valley, the steady cold air advection, and
moderate isallobaric couplet passing over the region will all
combine to produce gusty westerly winds across the entire Eastern
Great Lakes region tomorrow. Strongest winds will be across the lake
plains and east of Lake Ontario where gusts over 50 mph will be
possible. The position of the 40 to 45 knot low level jet, just a
thousand or so feet above the ground, coupled with the cold air
advection and deepening surface low may allow for wind gusts 45 to
50 mph over the higher hills of the region.
We will also have watch the lake seiche that will develop with the
strong southwesterly flow. Current thinking is that the rise in the
lake on the eastern end will be around 4 to 5 feet...or just below
advisory level.
The gusty winds and falling snow will bring areas of blowing snow
with reduced visibilities, first east of Lake Ontario where lake
snows will likely accumulate a few inches first, and then east of
Lake Erie tomorrow evening.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
...Significant Lake Effect Snows...
Arctic air will continue to pour across the lower Great Lakes
through the period as a deep trough gets carved out across the Great
Lakes region. Steady cold air advection with 850 mb temperatures
starting Wednesday evening around -15C falling to around -18C by
Friday morning. This will ramp up the over-lake instability with
lake induced CAPES up to 600 J/kg. Model soundings showing lake
induced equilibrium levels near 15K feet off Lake Ontario and near
10K feet off Lake Erie.
The 260-270 degree flow will focus the heaviest lake snows south of
Buffalo across the Chautauqua Ridge and the Tug Hill respectively
Wednesday night into Thursday morning. A passing short wave will
then back the flow slightly potentially shifts heavy bands
northwards into the Buffalo and Watertown areas, respectively. Bands
are expected to shift south once again Thursday night into Friday as
another short wave passes over the area.
With a long fetch down Lake Ontario and closer proximity to wrap-
around synoptic moisture, the Tug Hill should have no problem
accumulating at least 1-2 feet Wednesday night through Friday,
therefore the Lake Effect Snow Watch has been upgraded to a Lake
Effect Snow Warning.
Areas east of Lake Erie should easily see several inches of snow,
including the Buffalo metro area during Thursday, especially the
Southtowns. Lake parameters are not quite as outstanding as off of
Lake Ontario, with drier air aloft, lower inversion heights, and the
potential movement of the bands across the area leading to lower
snow totals. We are likely looking at least 6-12 inches with
localized highest amounts focuses just to the south of Buffalo and
along the Chautauqua Ridge. Enough confidence attained in newest
guidance to upgrade these areas to a lake Effect Snow Warning from
Wednesday afternoon through Friday. With the potential for the
heavier lake snows to shift a little father north toward the Buffalo
metro area, have decided to place northern Erie county into a Lake
Effect Snow Advisory for the immediate Buffalo southtowns.
Regarding temperatures, the arctic air pouring across the lakes will
be reinforced by several additional waves rotating through the
longwave trough that is progged to set up over the eastern half of
the country. Highs in the 20s Thursday will give way to teens Friday
with lows in the teens Wednesday night and Thursday night and
potentially in the single digits Friday night. The brisk westerly
flow will add to the chilliness, with wind chills falling into the
single digits Wednesday night and lasting at least into Friday
morning.
&&
.LONG TERM /SATURDAY THROUGH TUESDAY/...
Mid-winter cold should be with us through the weekend and early next
week, with another potent upper level trough diving out of the
Arctic and across the Great Lakes by Saturday. This will also
continue lake-effect snows downwind of the lakes through the
weekend, though we may see a little more weakening and movement in
the bands, particularly as flow veers more northwesterly Sunday in
response to strong ridging upstream.
At the moment, it appears that we may see a break in the cold by
Tuesday, as the general consensus among global models is for a deep
upper low to develop over the Gulf of Alaska by Sunday, forcing
ridging downstream across the Western U.S. that eventually works its
way eastward during the early part of next week, helping to break
down the longwave trough over the East and resulting in a more zonal
flow aloft, with relatively mild Pacific air flowing eastward across
the northern half of the country.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
The first area of steady rain will continue through the midnight
hour east of Lake Ontario before tapering off overnight. Another
batch of showers across Western NY will continue through late
evening and be re-enforced by a third area of rain over NE Ohio. The
combination of rain and BR will keep areas of MVFR and IFR VSBY
overnight, with widespread IFR CIGS. This rain will all taper off
from west to east Wednesday morning with the passage of a cold
front. VSBY will improve to VFR, and CIGS will also improve to a mix
of MVFR and lower end VFR.
Lake effect snow will then form east of the lakes for the last 6 or
so hours of the TAF period Wednesday afternoon and evening. Better
organization will be east of Lake Ontario where a band of snow may
bring IFR or lower flight conditions to KART. A more sheared
environment will produce more disorganized snows east of Lake Erie
tomorrow morning, but a band of snow will form by late morning as
low level moisture increases and a WSW flow brings snows across Ski
Country...with possible snows near KBUF and KJHW through 18Z.
In addition to the snows...Wednesday will become windy across the
TAF region as an area of low pressure deepens considerably over
Quebec, and surface high pressure noses towards the Ohio Valley.
Westerly gusts up to 40 knots will be possible across all 5 TAF
sites.
Outlook...
Thursday through Friday...Lake effect snow in the snowbelts east of
the lakes with MVFR/IFR. Otherwise VFR.
Saturday and Sunday...VFR/MVFR with a chance of snow.
&&
.MARINE...
A cold front will cross the lake waters tonight...this connected
from a deepening area of low pressure that will advance across Lake
Ontario and through southern Quebec. The combination of the
deepening area of low pressure, strong pressure gradient owing from
a building surface high pressure over the Plains and towards the
Ohio Valley and steady cold air advection through the day will bring
gale force winds on both lakes...starting in the west around 12Z,
and then by 15Z points eastward. Expect gales through the evening
hours of Wednesday before the departing surface low relaxes the
pressure gradient such that winds will drop below gale force late
Wednesday night/early Thursday morning.
A cold westerly flow through the weekend may kick up waves to low
end small craft advisory levels from time to time, but winds will be
much less this weekend than with the gales upcoming.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...Wind Advisory from 10 AM Wednesday to 1 AM EST Thursday for
NYZ001>004-010>014-019>021-085.
Lake Effect Snow Warning from 1 PM Wednesday to 5 PM EST
Friday for NYZ012-019-020-085.
Wind Advisory from 1 PM Wednesday to 10 AM EST Thursday for
NYZ005>008.
Lake Effect Snow Warning from 4 PM Wednesday to 5 PM EST
Friday for NYZ006>008.
Lake Effect Snow Advisory from 1 PM Wednesday to 6 PM EST
Thursday for NYZ010.
MARINE...Small Craft Advisory from 7 AM Wednesday to 10 AM EST Thursday
for LEZ020.
Gale Warning from 7 AM Wednesday to 7 AM EST Thursday for
LEZ040-041.
Small Craft Advisory from 7 AM Wednesday to 10 AM EST
Thursday for LOZ030.
Gale Warning from 10 AM Wednesday to 10 AM EST Thursday
for LOZ042>045-062>065.
&&
$$
SYNOPSIS...THOMAS
NEAR TERM...HITCHCOCK/THOMAS
SHORT TERM...TMA
LONG TERM...TMA/WOOD
AVIATION...HITCHCOCK/THOMAS
MARINE...THOMAS
Area Forecast Discussion
National Weather Service Green Bay WI
525 PM CST Tue Jan 3 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 238 PM CST Tue Jan 3 2017
The latest rap analysis and satellite/radar imagery show a potent
shortwave, located over the boundary waters of Minnesota, pushing an
arctic front across central WI early this afternoon. Still some
lower visibilities around 1 mile hanging on over the Door Peninsula,
but most locations have seen their visibilities improve above 3
miles. Looking upstream, though a narrow break in the clouds is
moving across the MN/WI border, there is another large area of
overcast conditions over northwest Minnesota where snow showers and
flurries are occurring. As arctic air plows across the region
tonight, light snow chances, clouds, and temps are the main forecast
concerns.
Tonight...The arctic front will finish crossing northeast Wisconsin
early in the evening. Cold advection will then continue through the
night, dropping 850mb temps to -18/-19C, and low temps into the
single digits. West winds will ramp up through the night, with some
gusts approaching 30 mph. This will drop wind chills over central
and north-central WI into the 15-20C below zero range by sunrise. In
addition, a potent upper shortwave will amplify across the western
Great Lakes, with comma head moisture spreading light snow showers
and flurries from northwest to southeast over the course of the
night. The most persistent snows should be over north-central WI,
where a minor lake contribution will occur over Vilas Co., and also
where mid-level moisture looks the most robust. Will show up to an
inch of snow there. Little to no accumulations are expected
elsewhere.
Wednesday...Upper troughing will slowly shift east across the
central Great Lakes but cyclonic flow will continue through the
column. Some residual moisture will linger in the 900-850mb layer,
which combined with steep low level lapse rates, should lead to
scattered snow showers and flurries across the area. Minor
accumulations under an inch could occur in the snow belts of n-c WI.
Highs ranging from the middle single digits above zero to the mid
teens near the Lake. Wind chills will approach -20C between 12-15Z
over central and north-central WI.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 238 PM CST Tue Jan 3 2017
Arctic air will remain over the region through the work week, with
a reinforcing shot arriving in the wake of another frontal passage
on Saturday. Precipitation chances will be minimal, except in
Vilas county, where scattered snow showers or flurries will occur
from time to time. The main story during this period is much below
normal temperatures, with the potential for wind chill advisories
west of the Bayshore and Fox Valley areas, where wind chills of
-20 to -30 F are possible Wed/Thu/Fri/Sat nights.
Arctic high pressure is expected to slide east of the region
Sunday night into Monday, with increasing south winds leading to
significant warm air advection. Aside from moderating temps,
there is a small chance of snow on Monday.
Both the GFS and ECMWF show a northern plains low pressure system
heading toward western Lake Superior Monday night into Tuesday,
with snow possibly mixing with or changing to rain as warmer
air arrives on Tuesday. Given the decent agreement in the medium
range models, will go with likely pops for day 7, which is usually
a risky proposition.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 525 PM CST Tue Jan 3 2017
West winds will be on the increase tonight and continue into
Wednesday in the wake of an arctic front. MVFR cigs over the
region early this evening may depart later evening or overnight as
drier air pours in. More MVFR clouds with SW-/SW-- over Minnesota
may work into the state from west to east late tonight into
Wednesday. This second area of clouds with the upper low system
will also be sliding over a drying boundary layer so coverage
will turn variable. Mvfr lake effect clouds will be more
widespread toward the Lake Superior snow belt region.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......TDH
Area Forecast Discussion
National Weather Service Grand Rapids MI
1048 PM EST Tue Jan 3 2017
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 326 PM EST Tue Jan 3 2017
Light rain and fog will move out of the area by this evening. Colder
air will then be spreading across the area later this evening and
through the overnight hours. This cold air will then produce lake
effect snow showers that are expected to last at least through
Friday. Normally favored lake effect areas will see multiple inches
of snow through Friday, with inland areas toward Clare and Lansing
seeing little to no accumulation. Blowing and drifting snow will
cause impacts for areas closer to the lakeshore late tonight Through
Wednesday with gusty winds.
&&
.UPDATE...
Issued at 1048 PM EST Tue Jan 3 2017
We are seeing several bands of showers (rain and snow) associated
with the passage of the arctic front early this evening. This was
shown well run after run with both the RAP and HRRR models. I
adjusted the hourly pops to show this feature. I will not add
much QPF however. There should be break in the snow showers after
midnight as we have to wait for the inversion height to get deep
enough to start the lake effect snow showers. This could take
until 5 to 7 am Wednesday morning. Given the gusty winds and
temperatures near 15 (more or less) these snow showers will
likely still cause travel issues this coming morning. I believe
our headlines are good.
I also lowered the hourly temperatures after midnight.
Temperatures are falling quickly in Wisconsin. Madison fell 16
degree between 5 pm and 10 pm this evening, from 32 to 16. Most
other stations in Wisconsin are seeing similar falls in there
temperature. This will cross the lake and reach our CWA after
midnight. I used the time delayed ensmebles of the HRRR and RAP
models to create the hourly temperatures. We could see
temperatures near 10 above in parts of our northern CWA by 7 to 8
am Wednesday morning. This will put wind chills into the 5 to 10
below range by Wednesday morning near Route 10.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 326 PM EST Tue Jan 3 2017
We will be letting go of the Dense Fog Advisory this afternoon, and
keeping the Winter Weather Advisory as is for tonight into Thursday.
The potential still remains that this may need to be extended at
some point, but there is plenty of time to monitor that need.
Winds have started to come around to the NW and pick up enough to
mix the low levels a bit and help to dissipate the fog as the low
exits to the SE. The change of the wind to be from the NW is
starting the process for the colder air to move over the area. It
seems like KLDM and KMBL are seeing the cold air move in with pcpn
starting to change over there. This will continue to spread through
the area, and all locations should be over to snow by 06z tonight.
We expect lake effect to start kicking in toward midnight when the
air is expected to become sufficiently cold enough. Inversion
heights will still be quite limited at that time, but will increase
to around 5-6k ft after 06z as the upper jet core sinks south
through the area. H850 temps will bottom out around -20 to -21C
around 18z on Wed producing delta t/s of mid 20s.
We are expecting numerous snow showers to be present in the favored
WNW areas from tonight, right on through Thu night and beyond with
some small fluctuations in the bands. The thought continues to be
that amounts will not be too heavy, but accumulations will add up
over the prolonged time frame. Limited inversion heights, and the
DGZ near or below the cloud base will be conducive for smaller
snowflake size and limiting the "fluff factor".
Blowing and drifting snow will be an issue with a fresh dry snow
falling and wind gusts up to around 35 mph or so late tonight and
Wednesday. The most impacted area will be generally west of U.S.-
131, maybe a little further inland along I-94 with the WNW flow.
This will become less of an impact Wednesday night and beyond as
winds will diminish a bit.
.LONG TERM...(Friday through Tuesday)
Issued at 326 PM EST Tue Jan 3 2017
Low level troughing persists along the lakeshore Friday into
Saturday...with a northwest flow prevailing. That combined with the
arctic airmass in place should result in continued lake effect snow
showers...most numerous generally along and west of Highway 131. The
greatest low level convergence remains situated from South Haven to
Muskegon. This is the region that should see the most snow in this
period.
The models for several runs have been showing a 700 mb wave tracking
through Friday am. This feature is forecasted to have relatively
deep moisture...up through -30 deg c. If this feature does
develop...the snow showers Friday morning could be quite heavy. Low
level convergence has the look of an I94 band setting up as this
feature tracks through. That would support the heavy snow bands
reaching well inland toward Lansing and Jackson.
Then Saturday night into Sunday...more of a northerly flow evolves.
This should cause the snow showers to migrate closer to the
lakeshore. Will feature the highest POPs from Ludington southward
through Muskegon and into South Haven. As the airmass will be
plenty cold enough for lake effect...and increased risk for a
heavier band of snow to develop exists.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 646 PM EST Tue Jan 3 2017
The arctic front is currently over eastern WI based on the surface
temperature and dew point gradient. The surface air temperature
was in the mid 30s along the lake shore over eastern WI but only
in the teens over the western part of the state. There is a band
of snow showers developing (mostly aloft now) along this front. I
do believe that the HRRR and RAP models depicting that band of
snow showers to develop and intensify as is crosses Lake Michigan
into lower Michigan between 9 pm and midnight makes sense to me. I
put TEMPO 1sm -shsn in most of the tafs to cover this band moving
through. After that there will be a break in the snow showers. The
actual lake effect event will begin after 10z and will continue
through most of the rest of the week actually. On Wednesday, due
to the strong winds the heaviest snow will be near US-131 by Thu
winds will be lighter and the heaver snow bands will be closer to
the lake shore.
&&
.MARINE...
Issued at 326 PM EST Tue Jan 3 2017
We have upgraded to a Gale Warning for the event from later this
evening through Wednesday evening effective immediately. Model winds
have trended up over the past 24 hours for the winds from tonight
through Wednesday evening as the cold air pours in over the area. We
are looking at gales up to 40 knots likely. Freezing spray will
become likely with the cold air, winds, and waves.
Winds will diminish some then late Wed evening, but remain in the
Small Craft Advisory category through Thursday with the cold air
coming over the relatively warmer waters.
&&
.HYDROLOGY...
Issued at 112 PM EST Tue Jan 3 2017
Precipitation totals over-performed previous forecasts with a
stripe of rainfall generally between 0.50-0.75 of inch, extending
from far southwest Lower Michigan to the Saginaw Bay. Localized
totals of around 1.00 inch cannot be ruled out when referencing
radar estimates and MRMS products. As a result, already saturated
ground soil has allowed moisture to quickly make it into streams
and rives to lead to fairly steep rises.
Fortunately, long range models do not bring any moisture laden
systems through over the next 7 days. We will transition to lake
effect snow over the next several days, placing much of any
additional moisture over extreme western portions of the state.
Concerns through Thursday and Friday will be in relation to ice
formation, as high temperatures sink near or below 20 degrees and
low temperatures consistently bottom out in the single digits and
low teens through Sunday.
Conditions will need to be closely monitored through the week
given high river levels and potential for ice formation.
Fortunately, only lead to minor river flooding immediately along
river banks and adjacent low lying areas.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory from 4 AM Wednesday to 10 AM EST
Thursday for MIZ037>039-043-044-050-056-057-064-065-071>073.
LM...Gale Warning until 10 PM EST Wednesday for LMZ844>849.
&&
$$
UPDATE...WDM
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...JAM
MARINE...NJJ
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
936 PM EST Tue Jan 3 2017
.SYNOPSIS...
A weak cold front will move off the the Carolina Coast later
tonight with colder air gradually spreading back over the region
on Wednesday and Thursday. A low pressure system is expected to
lift out of the Northern Gulf of Mexico early Saturday and could
bring widespread winter precipitation to the region.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
As of 9:35 EST Tuesday: Based on local radar trends and latest
RAP model data, we have slowed down the precipitation entering the
south end of the western North Carolina mountains. We still think
a secondary surge of moisture and DPVA will arrive, instigating
the shower activity. Thermal structure continues to only support a
mix to snow at the highest elevations in the wee hours Wednesday
morning.
Meanwhile, the cloud and fog forecast was adjusted to better fit
going conditions. There remains pockets of low clouds and patchy
to areas of fog ( some locally dense ) mainly in parts of the
western piedmont and foothills of North Carolina. High clouds may
have locked in some of the low clouds, and a few visibility
values are running around 1/4 mile. Meanwhile to the south, higher
clouds continue, along with some gradient. Nevertheless, with
winds on a downward trend tonight ( and thinning upper clouds ) we
would now expect some fog to re-develop. We have hit the fog
harder in our northeast forecast area, and brought more fog in to
the south. As it stands now, the dense fog appears isolated and
random from site to site. We have issued an SPS to call attention
to the changeable conditions. If the fog fans out, a Dense Fog
Advisory may be required.
Temperatures tonight seem to be doing okay, and only minor
adjustments made in that department.
Meanwhile the models favor this pattern persisting into daybreak
Wednesday as the flow is reinforced by an intruding cold front.
However, this front will advect much drier air into the region
yielding the end of any upsloping shra activity by late morning
into midday. As caa initiates and the atm cools from the top down,
and lingering high elevation precipitation cold change phase to a
rain/snow mix, before diminishing altogether.
Downsloping flow will dominate the pattern across the low
terrain of NE GA and the western Carolinas on Wednesday leading
to partly/mostly sunny skies and temperatures nearly 8-10 degrees
above normal, yet at or below normal westward atop the mtns thanks
to the developing caa. Lastly, winds are expected to increase
amidst improved H85 flow yielding strong, yet sub advisory wind
gusts across the northern mountains by early/mid morning lasting
through periods end.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
At 2 PM Tuesday: On Wednesday night a low amplitude upper trough
will be over the Easter USA, with low amplitude ridging to the
Western USA. The trough broadens to the west, and progresses slowly
across the Eastern USA through Thursday and Friday. Weak channeled
vorticity will round the base of the trough the period, but the
models disagree on timing and placement. The bulk of more
vigorous vorticity will pass well north of our area however.
At the surface, on Wednesday night dry high pressure will be over
our area, although the models show some high level cloud cover
moving over the area. a cold front will approach from the northwest
on Thursday, with vertical profiles supporting light snow in the NC
Mountains. As the front moves through our area Thursday night, snow
chances increase in it`s wake, mainly over the NC Mountains, but
perhaps spilling over the Blue Ridge to the Foothills and Piedmont
in robust northwest flow. Enough warming is expected during the day
to change precipitation over to snow along and east of the Blue
Ridge. Temperatures will fall from slightly above normal on
Wednesday night, to below normal in cold advection behind the front.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
As of 230 PM EST Tuesday...The main focus this period will be on the
possible winter event Friday night and Saturday. Models agree on a
system during this timeframe and that there will be some snow, but
the details of how much and where are still uncertain. The 12z GFS
has the coldest solution with mainly snow but the precipitation is
the lightest. The 12z runs of the ECMWF and Canadian models have
heavier precipitation but start it off as rain in the Piedmont
before transitioning to snow. GFS ensemble runs also run the gamet
in amounts due to similar differences. Plan to go with all snow in
the mountains with an initial rain/snow mix in the Piedment becoming
all snow Friday evening. Right now am thinking accumulations of 1-3
inches but this could change significantly with later forecasts.
The storm will quickly depart Saturday afternoon with cold high
pressure building in for the weekend into the first half of next
week. Expect highs in the 20s and 30s and lows in the teens to
around 20 Sunday and Monday. These readings may be a little colder
if there is actually snow on the ground. Temperatures will begin to
moderate some by Tuesday but conditions are expected to remain dry
after Saturday.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
At KCLT and Elsewhere: As noted earlier the slowly retreating
wedge boundary continues to lift north into locations north of the
airfield. Nevertheless, left over moisture and brief clearing has
allowed some stratus to develop in areas around KCLT. If winds
should drop off ( and we think they will ), we will probably note
a reduction of the stratus layer and the reformation of fog. As a
result we have trended the KCLT TAF in that direction, back to IFR
in CIGS and VSBYS.
Ample drying and subsidence Wednesday should scour any remaining
lower clouds or fog out by mid morning, with a trend to VFR.
Elsewhere a virtual smorgasbord of clouds and fog issues to the
north at Hickory, while AVL was waiting on clouds arriving from
the west. Plan to keep HKY down overnight, until we see
differently. Our southern TAF sites have cleaned out, to VFR
conditions, with the old front lifting north and some gradient. It
remains somewhat questionable how much fog will reform, but we
have allowed some stratus and fog to return / based on latest
guide / in the overnight hours. Therefore back to either IFR or
MVFR conditions.
Improving conditions then expected Wednesday and low level
moisture and sinking air scour any remaining clouds out.
Outlook: Drier conditions will persist into Wednesday. Tremendous
uncertainty then develops in the forecast for the weekend, with a
period of wintry weather possible at some point, most likely
Friday night into Saturday.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT Low 54% Med 72% High 100% High 100%
KGSP Low 55% Low 57% High 100% High 100%
KAVL Med 72% Med 75% High 86% High 100%
KHKY Med 66% Med 63% High 97% High 100%
KGMU Med 79% High 100% High 100% High 100%
KAND Med 66% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...JPT
NEAR TERM...CDG/TS
SHORT TERM...JAT
LONG TERM...SW
AVIATION...CDG/TS
Area Forecast Discussion
National Weather Service Lincoln IL
836 PM CST Tue Jan 3 2017
.UPDATE...
Issued at 836 PM CST Tue Jan 3 2017
Much colder and drier air moving into central and southeast
Illinois this evening following today`s cold frontal passage.
Temperatures this evening as of 8 pm range from 18 degrees in
Galesburg to 37 in Lawrenceville with temperatures already in the
teens upstream in Iowa poised to push into the area overnight.
Strong pressure gradients between the departing low and high
pressure over the Plains are resulting in windy conditions with 20
mph NW winds and gusts as high as 35 mph. Back edge to low clouds
and stratus is past Springfield to Peoria and should push east to
around the Indiana border by Midnight. Expecting lows tonight to
reach as low as 10 degrees for areas NW of Peoria ranging to the
low 20s south of I-70, with wind chills causing temperatures to
feel 10 to 15 degrees colder. Have updated forecasts for earlier
clearing and gustier winds this evening, and trended lows slightly
colder given th cold temperatures upstream advecting into the
area.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 210 PM CST Tue Jan 3 2017
A short wave will exit eastern IL late today as it moves into the
Ohio river valley. Rain showers east of the IL river will diminish
from west to east during the afternoon and early evening, ending
near the Wabash river by mid evening. Stratus deck with bases below
1k ft over IL. These low clouds were decreasing over central and
western IA and NW MO, and HRRR models shows these low clouds
decrease from nw to se during the evening, diminishing near the
Wabash river valley early overnight. An arctic cold front has pushed
southeast of the Wabash river by mid afternoon with brisk nw winds
15-25 mph dropping temperatures. Mercury levels currently range from
mid 30s nw of the IL river to the upper 40s near Lawrenceville. Low
temperatures tonight will range from 10-14F nw of the IL river where
wind chills will lower to 0 to 5 below zero later tonight into Wed
morning. Lows in the lower 20s from I-70 southeast where wind chills
reach 7-12F.
1038 mb arctic high pressure over MT ridges into the MO valley on
Wed and should provide a mostly sunny but cold day to central IL.
Mid/high clouds will be increasing during mid/late Wed afternoon
ahead of next wx system moving into the central plains. 850 mb temps
down to minus 10-14C on Wed gives cold highs in the lower 20s
northern CWA and upper 20s in southeast IL. Brisk nw winds to
continue tonight and Wed keeping wind chills down in the single
digits, and even zero to 5 below zero over northern/nw CWA.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 210 PM CST Tue Jan 3 2017
All models have now come into agreement and showing consistency with
previous run, in regards to the weather disturbance forecast to
quickly slide across the area Wed night through Thursday morning,
with a quick shot of snow. Very cold temps in the Arctic airmass
that is currently advecting into the region, will be cold enough
that any energy/vort max will produce enough lift for light snow and
flurries to be possible as it moves across the region. With airmass
cold and dry, snow to liquid ratios will be quite high. So with qpf
being small as well, not much snow will fall during the period in
the area. Current forecasted track of this piece of energy suggests
that most of the accumulating snowfall will be along and south of a
Quincy to Paris line. Snowfall amounts of around an inch or more
will be possible in west central IL. North of this area, flurries
are possible as forcing will be weaker and moisture more limited.
But, still wont take much forcing in the cold air to produce
flurries. However, for now, will just continue the slight chance of
snow in this area.
Beyond this mid week system, dry and very cold weather is expected
through the rest of the week and through the weekend. The high
pressure will not get east of the CWA til the beginning of the week.
Once this occurs, warmer temps will advect back northward into the
area, along with the chance of precip. This looks to begin by
Tuesday, so precip type will mix of rain and snow early and then
changing to all rain as temps warm well above freezing.
Temps overall this forecast package will be very cold with lows in
the single digits and highs in the 20s. Temps will begin to warm
starting Monday and then get into the 40s for Tuesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 541 PM CST Tue Jan 3 2017
Brisk NW winds behind a recent cold front will continue for the
next 24 hours with wind speeds 10-20 kts and typical gusts 20-25
kts. Wind speeds decreasing late in the 24 hour TAF forecast
period. Otherwise...IFR/MVFR cigs improving to VFR category by
3-6Z as dry air moves in from the NW. Isolated -DZ/-FZDZ early
this evening as precipitation rapidly diminishes from west to
east with colder air moving in to drop temperatures below
freezing.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SHORT TERM...07
LONG TERM...Auten
AVIATION...37
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
953 PM EST Tue Jan 3 2017
.UPDATE...
Issued at 953 PM EST TUE JAN 3 2017
Temperatures are now starting to fall over our western counties
signaling the passage of the cold front. Numerous showers
occurring in advance of the front will become more scattered in
nature and transition to drizzle overnight and this is handled
well in the forecast. No lightning has been observed this evening
so that threat was removed from the forecast.
UPDATE Issued at 537 PM EST TUE JAN 3 2017
Removed any mention of snow later tonight into Wednesday morning,
instead opting to transition showers to areas of drizzle before
ending as models indicate clouds shallowing out and remaining too
warm for ice to be present. Surface temps should stay above
freezing where any drizzle occurs so do not anticipate any issues
with freezing drizzle.
&&
.SHORT TERM...(This evening through Wednesday night)
Issued at 325 PM EST TUE JAN 3 2017
19z sfc analysis shows low pressure shifting east through the Ohio
Valley with a cold front stretched back west southwest into the
Southern Plains. This places eastern Kentucky in the system`s
warm sector with scattered to numerous showers passing through the
CWA under nearly overcast skies. Still looking at a potential for
the showers to become more convective and deeper late this
afternoon and into the evening - perhaps even to the point of some
thunder before the system`s cold front works through later
tonight. Currently readings are holding up in the upper 50s and
lower 60e with dewpoints just a category behind for most places.
The showers and low clouds are still bringing local patches of fog
and reduced visibility to parts of the area. Meanwhile, winds have
begun to swing more to the west with the sfc low now off to the
northeast.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict the southern stream wave
- responsible for our wet weather these past couple of days -
pulling off to the east this evening while a northern stream
trough pivots into the northern Great Lakes. This northern wave
drives height falls and energy deep into the Ohio Valley tonight
as fast flow moves through Kentucky. This is well modeled through
the day Wednesday even as it lifts northeast into Ontario and
Quebec. Behind this, a much broader trough will take shape and
start to shift south into the Upper Midwest by Thursday morning
with bigger implications for our weather for the latter part of
the week. Given the good agreement for the bulk of the short term
will go with a blended solution with the HRRR and NAM12 favored
in terms of details.
Sensible weather will feature scattered to numerous showers into
the evening with even a rumble of thunder possible. CAA will
kick in late this evening as a cold front crosses eastern
Kentucky. This will end the threat of thunder and also bring in
brisk conditions with northwest winds of around 10 mph continuing
into the early morning hours of Wednesday. The moisture will
shift off to the east just as the column cools enough from west to
east for a brief transition to snow flurries when the pcpn exits
to the east. Of note, will be a return of sunshine on Wednesday
as high pressure quickly moves into the area, but temperatures
will not rebound much from the morning lows. Later that night, cold
air continues to pour into the area with temperatures bottoming
out in the lower 20s most places by Thursday morning - this is as
the next sfc wave approaches and brings lowering clouds into east
Kentucky by morning - with snow not far behind. See below for more
details on this cold and snowy blast to end the work week.
Per the usual, started with the CONSShort and ShortBlend for most
of the wx elements with only minor adjustments in the near term
to account for current conditions and then fine tuned lows
Wednesday night. Also, beefed up PoPs through the first part of
the night and held them in a tad longer in the far southeast for
Wednesday morning.
.LONG TERM...(Thursday through Tuesday)
Issued at 245 PM EST TUE JAN 3 2017
The focus in the extended period will be the Thursday and Thursday
night time frame. The model data is finally beginning to come into
some agreement regarding the passage of a trough of low pressure
aloft Thursday and Thursday night. As of now, the thinking is that
an upper trough will move quickly across the Great Lakes region
toward the end of the week. A potent shortwave is forecast to move
quickly across the Ohio and Tennessee valley regions around the base
of the upper low. With cold air already expected to be firmly
entrenched across the region, any precipitation that falls Thursday
and Thursday night will be in the form of snow. With the models
coming into some agreement, and with the latest MOS data having
higher pops, decided to increase the precipitation chances for
eastern Kentucky Thursday and Thursday night. Also increased the QPF
and snowfall amounts as the model data has also trended in that
direction. Most locations can tentatively expect between a half inch
and an inch of snow Thursday and Thursday night. The higher terrain
along the Virginia border may see just over an inch. Areas along and
north of I-64 may also pick up around an inch, as the precip is
expected to begin there first and will be closer to the center of
the passing shortwave. The snow may last into the day on Friday, due
to moist upslope flow.
After the snow ends on Thursday, it looks a dry forecast through the
beginning of next week. Temperatures will be running below normal
across the area, with daily highs in the 20s and 30s expected each
day. Nightly lows should be in the teens and 20s on Friday, and in
the teens Saturday through Monday. Conditions should improve
slightly for Monday and Monday night, with highs forecast to warm
into the upper 30s and lower 40s, and lows in the 20s expected. A
few location in our higher terrain may even fall into the single
digits Sunday and Monday morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 638 PM EST TUE JAN 3 2017
A cold front now located across central Kentucky will continue
pushing eastward across eastern Kentucky this evening. Ahead of
the front, numerous showers will be found with ceilings varying
from low MVFR to IFR. Behind the front, ceilings are expected to
drop to LIFR and the showers will transition to areas of drizzle.
Ceilings will then trend upward late tonight into Wednesday
morning as colder/drier air starts to advect into the region in
the low levels. This should result in a return to MVFR ceilings
shortly after dawn and then a scattering out of the clouds from
west to east during the late morning. TAFs portray the above
expectations but confidence on the timing of the category changes
is low.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...ABE
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...ABE
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
911 PM CST Tue Jan 3 2017
.SYNOPSIS...
Issued at 307 PM CST Tue Jan 3 2017
A more zonal H5 pattern has developed across the
western CONUS over the past 24 hours. A strong shortwave remained
off the coast of Oregon, however, 50+ meter HT rises were noted
over the pacific Northwest into Idaho and northern Nevada this
morning. With this noted, the feature off the coast of Oregon,
should remain stationary over the next 24 hours. West of the west
coast shortwave, a positively tilted ridge of high pressure extended
from the Gulf of Alaska into northwestern Nunavut Canada. East of
the apex of the ridge, a closed low was present over northern
portions of Hudson Bay. On the western and southwestern periphery of
the low, two shortwave troughs were present, one due west of the low
and a second which extended southwest of the low into southwestern
Canada. At the surface, arctic high pressure was anchored over
southeastern Montana and extended south southeast into northwestern
Nebraska. With the exception of some thin mid and high clouds in
association with a jet streak, skies were mostly clear to partly
cloudy. Temperatures were cold across western and north central
Nebraska with 3 PM CST readings ranging from 9 at Valentine to 20
at Imperial.
&&
.UPDATE...
Issued at 910 PM CST Tue Jan 3 2017
The faster RAP and HRRR models are handling the snow across Wrn
Neb the best. A new forecast is in place for the developing snow
using a blend of those two models plus the previous forecast.
Snow production shown by the webcams in the Scottsbluff area look
good.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 307 PM CST Tue Jan 3 2017
Clouds will be on the increase tonight as mid level moisture spreads
eastward across the area. Lower clouds (stratus) will also develop
across portions of the panhandle through southwest Nebraska by
daybreak Wednesday. Northern Nebraska will be the last to see the
clouds increase tonight, and will drop a few degrees below zero.
These areas will also see the coldest wind chills and a wind chill
advisory will remain in effect.
Mid level frontogenesis will strengthen Wednesday morning, and snow
will develop in a band from western through southwest Nebraska by
noontime. Cross sections indicate the potential for some banded
moderate snow intensities, and expect a general 1 to 3" inches with
an isolated higher amount near 4" not out of the question. This is
mainly due to the dry powdery nature of the snow. Winds will be
light and blowing snow will not be an issue. Across portions of
central and especially north central Nebraska, drier air in the
lower levels will limit snow to just light or flurries. Little
accumulation is expected for these areas.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 307 PM CST Tue Jan 3 2017
Wednesday night through Friday: In the mid range,
lingering snow chances Wednesday night and temperatures are the main
forecast challenges. Decent mid level frontogenesis and isentropic
lift on the 285K surface, will continue into the evening hours
across the southern half of the forecast area. Both the latest NAM12
and GFS solutions are in decent agreement with the location and
southward track of this lift into the overnight. QPF forecasts for
tomorrow evening are on the order of five to ten hundredths for
North Platte during the evening hours. Utilizing a 18-1 ratio of
snow to rain, yields around an inch to an inch and a half for North
Platte. Add this to what is expected Tuesday afternoon and North
Platte is looking at around two inches of snow. Some higher amounts
of up to 3 inches are possible in Garden and Deuel County. With
light winds expected Tomorrow afternoon and Wednesday night, will
forgo a winter weather advisory since snowfall is on the order of 1
to 3 inches. Across northern Nebraska, a reinforcing shot of arctic
air will push into the area overnight. By Thursday morning, lows
will range from zero to 12 below zero over the Pine Ridge. With the
weak cold air advection Wednesday Night, winds will not totally
decouple overnight. That being said, northerly winds around 10 MPH
will combine with below zero temperatures, producing wind chills as
low as 15 to 30 below zero across the northern half of the forecast
area. This will probably necessitate the eventual issuance of a wind
chill advisory for Wednesday night. This area is already covered
with a wind chill advisory for tonight, so will hold off issuance
till tonight to avoid confusion. On Thursday, cold air will remain
anchored across western and north central Nebraska as high pressure
builds across the sandhills. With respect to highs, Thursday will be
the coldest of the next 7 days with highs in the single digits to
the lower teens. Fresh snow cover across southwestern Nebraska will
limit highs as well. High pressure will drift southeast into Kansas
Thursday night, forcing the coldest air to the south and east. With
clear skies and light winds in place, lows will bottom out in the -2
to -12 degree range and may need to be adjusted even lower across
southwestern Nebraska where fresh snow cover will reside.
Friday night through Tuesday: Ridging aloft will begin to build
into the Rockies and Plains into the weekend. After highs in the
20s Saturday, readings will trend upward into the 30s Sunday,
followed by 40s on Monday and Tuesday. With the exception of some
slight chances for precipitation Tuesday, the extended periods
will be dry. The warmup appears short lived however, as another
arctic front may arrive late next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 538 PM CST Tue Jan 3 2017
The radar returns in central WY are expected to move east and
expand in coverage across the Nebraska Panhandle and Western
Sandhills tonight. It is believed this area of snow will move
east Wednesday morning affecting I-80...KLBF and the Central
Sandhills. IFR is expected to become widespread in light snow and
low cigs.
The RAP model and HRRR suggest an area of MVFR in snow and low
cigs will develop and affect KLBF 06z-12z. This is under review.
There is also an area of MVFR cigs over the Cheyenne divide right
now shown by sfc obs and this area of low clouds is being
monitored as a possible area of snow development this evening.
Lastly...the SREF shows IFR in snow not affecting KLBF and I-80
directly Wednesday but casts this area of snow farther north
toward KTIF. Thus there is uncertainty as to where exactly the
snow will develop tonight and Wednesday and the solution to this
problem will not be understood until later tonight or Wednesday
morning once the snow band develops.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Wind Chill Advisory until noon CST /11 AM MST/ Wednesday for
NEZ004>006-094.
&&
$$
UPDATE...CDC
SYNOPSIS...Buttler
SHORT TERM...Taylor
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Marquette MI
535 PM EST Tue Jan 3 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 406 PM EST TUE JAN 3 2017
WV imagery and RAP analysis indicated a mid/upper level low near
KINL. A surface trough extended from low pres over Lake Erie through
Lake Huron and eastern Upper Michigan to central Lake Superior.
Westerly flow behind the trough was bringing in drier through the
western cwa. Some weak LES bands have developed over wrn Lake
Superior limited by marginal instability (850 mb temps
around -10C) and relatively dry air upstream over ne MN.
Tonight, satellite trends and short range high res models suggest
that the stronger LES supported by low level conv near the low and
trough axis over nrn Lake Superior will be slower to slide
southward into the nw cwa with a heavier burst of snow over the west
arriving mainly between 03z-06z. However, expect at least light to
moderate snow this evening. Similarly, the trough may also arrive
later into the ne cwa between 09z-12z/Wed. Once the winds veer to the
nw the deep moisture, colder air (850 mb temps to near -20C) and the
arrival of 700-300 mb qvector conv with the mid level low will
support stronger LES. The DGZ position in the convective layer will
also be favorable for snow growth with higher SLR values. 3 to 6 inch
amounts will be common. So, no significant changes were made to the
warnings and advisories other than to mention the later arrival of
the heavier snow.
Wednesday, multiple wind parallel LES aligned with cyclonic 320-340
flow will bring the heaviest snow into the west in the higher
terrain between IWD and CMX and over the east from P53 eastward.
Although the DBZ drops closer to the surface, the deep instability
with the departing mid level low will still support moderate to
heavy accumulations with 3 to 6 inch amounts again in the nw flow
favored locations. In addition considerable blsn is expected in
exposed locations near the Lake.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 253 PM EST TUE JAN 3 2017
The main forecast highlights Wednesday night through early next week
are persistent LES into this weekend across the west and northwest
wind snow belts and the arrival of bitterly cold arctic air, before
another system is progged to lift into the region next week bringing
a chance for system snow across the area.
Wednesday night into Thursday expect moderate to heavy LES to
continue with models showing ample lift through the dendritic
growth zone early on. Expect blowing snow to also be an issue in
locations that see LES. As we progress through the overnight hours
and Thursday much colder 850mb air wraps around the occluded system,
lifting north across eastern Canada, and will allow for a bitterly
cold arctic airmass to move over the region. This colder air will
allow snow ratios to lower throughout the end of the week as forecast
soundings show the thickness of the dendritic growth zone thinning.
This coupled with winds backing a bit west-northwest still thinking
that a few periods of moderate LES will be possible through
Thursday/Thursday night, but the heaviest snowfall should occur
Wednesday night into Thursday. Temperature wise, the middle of the
week into the weekend looks bitterly cold with overnight lows
dropping into the single digits and even below zero across the higher
terrain. Afternoon highs are only expected to reach the single digits
across western portions of the area with teens across the east.
Thursday night into Friday morning although the winds are expected to
lessen, the remnant winds and bitterly cold air will allow for wind
chills to drop to around -22 to -26, approaching advisory criteria.
Through the end of the week and into the weekend, LES will continue
to shift into the west wind snow belts before gradually weaken and
move offshore towards the end of the weekend. Early next week 850mb
winds will back to the southwest with return flow advecting northward
ahead of a system progged to lift north across the region. This will
also allow temperatures to gradually warm back up into the 20s
towards the end of the weekend/early next week. In regards to the
system for next week, there is good agreement amongst the GFS/ECMWF
with the system swinging through the region Tuesday into Wednesday.
Even though soundings show a stout warm nose advecting overhead, at
this time it does not look 850mb temperatures will be warm enough to
promote melting of ice crystals, so have opted to keep mentions of
all snow for now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 535 PM EST TUE JAN 3 2017
Conditions will drop this evening and overnight at IWD and CMX to
IFR in moderate to heavy lake effect snow and blowing snow in the
wake of a strong cold front. SAW will likely see improvement to high
end MVFR or low end VFR this evening as winds shift to a downslope
westerly direction. MVFR conditions and some lake effect snow will
return to SAW late tonight as cold front moves through the area.
Conditions at SAW will fall to IFR Wed morning into Wed afternoon
with the lake effect snow showers.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 406 PM EST TUE JAN 3 2017
As a trough deepens over the lake and colder moves in behind it,
northwest gales to 35 knots are expected across the lake beginning
this evening in the west and later on tonight in the east. Gales will
diminish Wed morning over the west, but will continue through much of
Wed over the east half. Expect northwest winds of 20 to 30 knots
Wednesday night to diminish to 15 to 25 knots Thursday then become
more westerly on Friday. There is a potential for heavy freezing
spray Wednesday into Friday as Arctic air moves over the area.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Lake Effect Snow Advisory from 9 PM this evening to 7 PM EST
Wednesday for MIZ004-084.
Lake Effect Snow Warning from 1 AM Wednesday to 7 AM EST Friday
for MIZ006-007-085.
Lake Effect Snow Warning until midnight EST Friday night for
MIZ001>003.
Lake Effect Snow Warning until noon CST Thursday for MIZ009.
Lake Superior...
Heavy Freezing Spray Warning from 4 AM Wednesday to 10 AM EST
Thursday for LSZ265>267.
Gale Warning from 4 AM to 4 PM EST Wednesday for LSZ249>251-266-
267.
Gale Warning from 1 AM to 1 PM EST Wednesday for LSZ243>245-248-
264-265.
Heavy Freezing Spray Warning from 1 AM Wednesday to 10 AM EST
Thursday for LSZ264.
Gale Warning from 9 PM EST /8 PM CST/ this evening to 7 AM EST
/6 AM CST/ Wednesday for LSZ162-240>242-263.
Heavy Freezing Spray Warning from 1 AM EST /midnight CST/
Wednesday to 4 AM EST /3 AM CST/ Thursday for LSZ162-263.
Lake Michigan...
Gale Warning from 10 PM this evening to 5 PM EST Wednesday for
LMZ221-248-250.
&&
$$
SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Nashville TN
741 PM CST Tue Jan 3 2017
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Cold front currently working across eastern middle TN at this
hour. Scattered light shower activity is primarily located along
and east of the boundary. Temperatures have dropped into the upper
40s across northwest areas and the caa is still expected to
continue area wide overnight. Upper level energy in the post
frontal sector is rather weak and the vorticity advection has
gone negative across our northwestern areas where little if any
rainfall is now occurring. Latest Hrrr and model data shows that
the precipitation should continue to gradually decrease through
12z from west to east. Looking at the current weather grids, I see
no reason to make any modification at this point.
Remainder of fcst appears to be in good shape as well. Although,
latest 12z temp progs are running a little lower than our fcst
min temps. Will go ahead and lower min temps a degree or two.
update out shortly.
&&
.AVIATION...
00Z TAF DISCUSSION.
As sfc cold front pushes thru mid state, mainly along and ahead,
some light shwrs will be possible, in at least vcnty of terminals.
Vicinity of shwr potential will dissipate after 04/05Z. However,
it will take some time before IFR to MVFR ceiling erosions to take
place, as strong sfc ridging influences try to build in from the
northern Rockies thru 04/24Z. It looks like ceiling erosions will
occur slowly from west to east from around 04/10Z west to around
04/19Z east, as a weak upper level trough passage and dry quasi
zonal flow aloft become established thru 04/24Z. Sfc gusts before
and shortly after frontal passage up to 20kts should generally
subside between 04/12Z-04/18Z as sfc pressure gradient finally
weakens and winds become predominate nwly 5 to 10 kts.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......21
AVIATION........31
Area Forecast Discussion
National Weather Service Springfield MO
610 PM CST Tue Jan 3 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 206 PM CST Tue Jan 3 2017
Cloud cover, fog and patchy drizzle persisted across the area this
afternoon. A sharp clearing line was moving slowly southeast
across Eastern Kansas and Northwest Missouri. This delineates a
drier airmass moving toward the area. Northwest upslope flow along
the Ozark Plateau typically suggests that this clearing line will
struggle tonight to move through. The RAP 850mb-925mb layer RH is
handling the location of the clearing well however we have slowed
down the clearing line through the area more than short term
models suggest. Patchy fog may persist into the evening mainly
along and south of Interstate 44 however with winds remaining up
an drier air advecting in with time do not expect any dense fog.
Low temperatures will ultimately depend on cloud cover tonight
however with continue cold air advection temps should still fall
into the teens in most places. Temps on Wednesday will likely
remain at or slightly below freezing.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 206 PM CST Tue Jan 3 2017
A shortwave trough will move down from Montana into the Northern
Plains late Wednesday. Sufficient lift and mid level moisture
with this feature will combine to produce a band of light snow
mainly between US Highway 54 and Interstate 70 in Central
Missouri. QPF amounts look very light however with high SLR around
16-17:1 there could be a quick 0.5 to 1 inch mainly along and
north of US Highway 54 late Wednesday night into early Thursday
morning. Both the NAM and GFS keep all precip north of Springfield
while the ECMWF and Canadian brings things ever so slightly
south. Confidence is increasing that the best chance for snow
will be north of Springfield. Any light snow or flurries will
likely end during the daytime Thursday.
Cold but dry conditions persist for the remainder of the week as
high pressure moves in. Both long range models are showing a
warming trend late in the weekend into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 605 PM CST Tue Jan 3 2017
An MVFR cloud deck will clear from northwest to southeast across
southern Missouri this evening. While the back edge of the clouds
may hang-up for an extra hour or two due to local terrain effects,
we are expecting the back edge to clear Branson before midnight.
VFR conditions and some high clouds can then be expected
overnight and into Wednesday. Surface winds will remain out of the
northwest and will slowly diminish this evening.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Burchfield
LONG TERM...Burchfield
AVIATION...Schaumann