Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/30/17

Area Forecast Discussion

National Weather Service State College PA

 1033 PM EST Sun Jan 29 2017

.SYNOPSIS...
An upper level trough over the eastern contiguous US will be
reinforced this week by successive shortwaves diving southeast
across the Great Lakes. One weather system will pass south of
the CWA tonight bringing a quick period of flurries or light
snow showers to southern PA. Another Alberta Clipper associated
with one of these shortwaves will track just north of
Pennsylvania on Tuesday bringing the best chance of snow to the
region for the next several days. Temperatures will be fairly
close to average through the period.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Forecast on track as shortwave and best dynamics passing south
of the CWA. Radar shows a few light showers traversing across
southern zones which is well covered in forecast. Previous
discussion... Our next potential weather
maker...a potent shortwave dropping southeastward from the
western Great Lakes tonight and Monday... now appears to be
digging far enough south to prevent much if any impact north of
the Mason Dixon line. Earlier ensemble solutions suggested that
the Monday morning commute across my southern tier had an
outside shot at receiving an inch or more of snowfall...but
latest consensus from 12z suite and CAMs indicates this threat
has diminished. Still...a period of light snow and flurries is
likely as this system tracks south of the region late tonight
and Monday morning before deepening rapidly off of the mid
Atlantic coast. One can see the system nicely on visible
satellite shots at 3 PM. Have a nowcast out for this.

Mins tonight will range from 10-15F north and lower to middle
20s south.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Sfc wave tracks south of the Mason Dixon line early Monday
before enhancing along and just off the mid Atlantic coast later
Monday. Any lake connection and upslope flow will be limited
Monday afternoon and evening...producing local 1 inch plus
amounts over the Laurels and Northwest mountains.

The threat of snow showers diminishes Monday afternoon, as
ridging builds in from the Ohio Valley. SFc ridge axis will
reach into southwest PA by evening. Maxes will range from the
low to mid 20s north to the mid 30s southeast.

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Did not change much on this package.

Went a degree or so lower Monday night in a few spots. Also
a little lower with snowfall amounts for Tuesday, given track
of the low, and expected high temperatures, as the low track is
north of the PA border.

Confidence increasing in a fairly widespread light snowfall Tuesday,
as all med range guidance tracks a fast moving Alberta Clipper
into the area from the Grt Lks. Current guidance suggests the
best WAA will occur during the first half of the day and the
SSW flow will favor the NW Mtns to receive the greatest amounts
due to orographic enhancement.

Global model and ensemble consensus keeps a mean trough in the
Eastern U.S. this week, which should result in below average
temperatures. Within this flow regime, no major synoptic scale
winter storms are anticipated through Sat. However, persistent,
generally light Lake effect snow is likely to result across the
NW Mtns and Laurels.

Some potential for a weak southern system next Sunday, and a
cold front to the west. For now, tapered off snow after sunset
on Sunday, as I am not seeing a lot of support for a system from
the southwest.

&&

.AVIATION /04Z MONDAY THROUGH FRIDAY/...
Low stratocu continues to be draped over the region this
evening. All stations are VFR and should remain through at
least the first half of the evening. Another system moving in
from the west tonight will again bring reductions back,
especially into western portions of the cwa. However the latest
mid to short range models, including the SREF and the NAM has
some light snow showers moving in early tomorrow morning. The
HRRR has continued to diminish any snow showers. So have backed
off on restrictions for most TAF sites outside of JST and BFD.
The westerly flow should still have some moisture associated
with it, and given the orographic lift should be enough for MVFR
cigs and vsbys at BFD and JST with periods of IFR possible. The
best chance for IFR at JST after 09Z. Conditions should improve
as Monday continues.

Outlook...

Tue...Clipper system will bring widespread reductions and light
snow - with biggest impacts NW half of CWA.

Wed-Fri...Generally MVFR to occasional IFR in snow showers
BFD/JST. VFR with ocnl MVFR east.

&&

.EQUIPMENT...
KFIG surface observation will be off line for an extended
period of time due to failed power feed to the DCP.

&&

.CTP WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$
SYNOPSIS...Ross/DeVoir
NEAR TERM...Ross/DeVoir
SHORT TERM...DeVoir/Martin
LONG TERM...Fitzgerald/Martin
AVIATION...DeVoir/Ceru
EQUIPMENT...




Area Forecast Discussion

National Weather Service Green Bay WI

 836 PM CST Sun Jan 29 2017

Updated aviation portion for 06Z TAF issuance
and new information added to update section

.UPDATE...
Issued at 833 PM CST Sun Jan 29 2017

No changes to winter weather headlines this evening. The 00Z NAM
has finally come into line with the ECMWF/GFS in depicting a more
southerly track of the strong shortwave and associated cyclone
crossing the region tomorrow. Hunch right now is that advisory
start times are a bit early, but confidence in that is not high
enough to adjust with at this point.

Also believe we will eventually need to add another tier of
counties along the northeast edge of the advisory (at least
Oconto/Door, and possibly Forest). The heavier snows could linger
a little longer along the lakeshore--especially in Door and
Kewaunee counties as it appears an inverted trough is likely to
set up near the lakeshore tomorrow night as the surface low
slides by just to the south of the forecast area. There is still a
lot of snow shower activity over the lake now, and temperatures
tomorrow will support at least lake enhancement and possibly even
a true lake-effect band.

As far as snow totals go, this system has quite a bit going for
it. The upper support looks very impressive on water vapor
satellite imagery this evening as it plows across British Columbia
and into Alberta. Temperatures will favor fairly high snow-to-
water ratios, and the available moisture working east in advance
of the cyclone is fairly robust for a northwest flow system. In
addition, the cold pocket that dropped south into the area behind
the shortwave that crossed our area during the past 12-18 hours
will leave behind a fairly strong baroclinic zone with which to
generate isentropic lift. Given these factors, snowfall totals
may need to be edged up, especially along the axis of maximum
snowfall. However, there is concern that the axis of maximum
snowfall will be fairly narrow, so the increase will need to be
targeted, and will defer to the next shift which will have the
benefit of the entire 00Z guidance suite including the ECMWF,
which has been the most consisent model in handling this system.

Updated product suite will be out ASAP.
&&

.SHORT TERM...Tonight and Monday
Issued at 225 PM CST Sun Jan 29 2017

The latest rap analysis and satellite/radar imagery show a surface
ridge axis shifting east over the northern Plains.  But cyclonic
northwest flow continues unabated over the western Great Lakes,
which is contributing to widespread clouds, snow showers and
flurries. Clearing has been inching eastward into western Wisconsin
early this afternoon, but flow off Lake Superior has slowed this
progression down somewhat.  Visibilities in the snow belt of Vilas
county have improved this afternoon and have already dropped the
winter weather advisory. Did receive a report of 3 inches at Land O
Lakes.  The next clipper is looking rather impressive over British
Columbia.  Forecast concerns include clouds and snow shower trends
tonight, followed by potential accumulations on Monday.

Tonight...Cyclonic flow will continue through the evening, with
northwest flow off Lake Superior.  Despite clearing taking place
upstream over western Wisconsin, think clouds will hang on a little
longer than anticipated, so increased cloud cover for the evening.
Some flurries may also linger over eastern WI as well. But the
general trend will call for decreasing clouds, especially mid to
late evening through the overnight as a weak surface ridge axis
arrives, causing winds to back to the west.  Temps are rather
difficult to project due to the potential for clearing and light
winds for a few hours late tonight.  Stuck mostly with the previous
forecast, though some of the cold spots of n-c WI could be several
degrees colder than forecast if the clouds erode faster than
expected.

Monday...Clouds will on the increase once again ahead of a fast
moving clipper system which is expected to drop southeast into the
northern Mississippi Valley by the end of the afternoon.  Followed
the southern solutions of the ecwmf/gfs/wrf-arw for the track of the
surface low based on model comparisons.  An area of light to
moderate snow will be spreading southeast into central and north-
central Wisconsin by late morning into early afternoon as mid-level
thetae advection and fgen arrive ahead of the clipper.  This forcing
in conjunction with arrival of a potent vort will then push the
snowfall into eastern WI by around mid-afternoon.  This snowfall
should be of lighter/drier variety due to snow ratios between 15-17
to 1.  By the start of the evening commute, 1 to 3 inches of
accumulations will be possible from east-central to north-central
WI, which will create slippery and snow-covered roads.  With
coordination from offices to the west, will hoist a winter weather
advisory starting around midday over north-central WI and mid-
afternoon over eastern WI.

.LONG TERM...Monday Night Through Sunday
Issued at 225 PM CST Sun Jan 29 2017

The primary isent lift region ahead of a clipper system will
shift over northeast Wisconsin by early Monday evening before
sliding east of the area. Progs still not quite in agreement with
the track and timing of various parameters with this system. The
NAM continues to track the surface low along the Wisconsin and
Upper Michigan border, while the GFS tracks the surface low much
further south, reaching the Fox Cities Monday midnight. The 12z
ECMWF is similar to the GFS run. Focusing at the 700 mb level and
the primary snow growth region shows the mid level trough for the
nam is slower early Monday evening but then catches up with the
GFS and ECMWF solution by Monday midnight.

Primary period of accumulating snow expected through Monday
evening as the mid level trough passes through. Snow is expected
to taper off later Monday night into Tuesday, however upper jet
location is indicating additional brief periods of lighter snow
accumulation through at least Tuesday. Continued height falls
into Tuesday evening hinting on subtle short waves with possible
upper jet let support. Will lean with the higher end GFS chc pops
for Tuesday.

Lake effect snows will linger into Wednesday across the far north,
otherwise a quiet drier and colder period for the rest of the
work week.

Another chance for snow possible the later half of next weekend.
&&

.AVIATION...for 06Z TAF Issuance
Issued at 833 PM CST Sun Jan 29 2017

Scattered SHSN have tapered to flurries. Ceilings were generally
VFR, and clouds were decreasing from the west. Expect generally
good flight conditions for the next 15-18 hours, then conditions
will deteriorate rapidly as a band of snow moves in from the
west. Anticipate flight conditions quickly lowering to IFR as the
band settles over the region tomorrow afternoon, with the poor
conditions lingering into the evening.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 3 PM Monday to 4 AM CST Tuesday for
WIZ020-031-037>040-048>050.

Winter Weather Advisory from 11 AM to 10 PM CST Monday for
WIZ005-010-018-019-030-035-036-045.
&&

$$

UPDATE.........Skowronski
SHORT TERM.....MPC
LONG TERM......TDH
AVIATION.......Skowronski




Area Forecast Discussion

National Weather Service Lincoln IL

 904 PM CST Sun Jan 29 2017

.UPDATE...
Issued at 904 PM CST Sun Jan 29 2017

Current forecast is not too bad. However, clearing from the
northwest is coming in quicker than first thought and isolated
flurries still continue over parts of central and eastern IL this
evening. Also, winds behind the departing short wave/vort max seen
on radar, briefly increase with isolated gusts to around 20 mph.
Will make some adjustments to the forecast for the remainder of
the night to account for differing trends. Update out shortly.

&&

.SHORT TERM...(This evening through Monday)
ISSUED AT 236 PM CST Sun Jan 29 2017

Latest vort max continues to drop southeast in the fast northwest
flow this afternoon, entering the Chicago metro area, with another
narrow channel further west from western Minnesota into Missouri.
Snow flurries and some heavier showers continue to be prevalent east
of the Mississippi River, with some earlier reports of sleet near
Lawrenceville. Some of the heavier showers have produced a couple
tenths of accumulation and lower visibilities, with these showers
being focused in the Galesburg to Mattoon corridor since late
morning. Focus for the flurries/showers will be shifting east this
evening as the vort max drops into western Indiana. Will maintain
some mention of flurries into early evening over far eastern
Illinois.

Large area of clearing over Minnesota is edging into northern Iowa
this afternoon, and RAP 925-850 mb humidity plots showing the
associated drier air scouring out the air mass over us this evening.
Skies will become partly cloudy as a result, but they will start
filling in again Monday morning ahead of a warm front. This front is
associated with a clipper that will dive southeast out of
Alberta/Saskatchewan. The precipitation with this clipper will stay
to our north. Temperatures should warm up nicely and reach the lower
40s over the southwest/southeast CWA, with mid 30s north of I-74.

.LONG TERM...(Monday night through Sunday)
ISSUED AT 236 PM CST Sun Jan 29 2017

Mostly quiet weather is expected across central and southeast
Illinois through the period. However, as the upper-level flow will
be trending more zonal this week, the predictability of smaller
scale waves and their impacts is likely to be shaky. This zonal flow
will also allow temperatures to moderate from their current levels,
but a significant warm-up is not anticipated. At this point, Tuesday
is expected to be the warmest of the week with highs in the 40s.
Otherwise, readings should stay within a few degrees of normal
through the period. The next weather system of interest for our area
is not expected before Saturday night or Sunday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 540 PM CST Sun Jan 29 2017

All sites should be VFR rest of the evening. However, there is
still some light snow bands/flurries still occurring along the
I-74 corridor early this evening. So, will be keeping VCSH at
PIA/BMI/CMI for 2-3 more hours with cigs dropping to MVFR during
the light snow. This light snow should remain east of SPI and DEC
this evening. Satellite trends show a large clearing area across
MN and IA that is slowly working its way into the area. So,
expecting clearing to occur at all sites, but not until close to
midnight, starting in the west and then advecting toward the east
after midnight. Will not completely clear things out, but will
have scattered clouds instead. Models do show another batch of
clouds coming into the area tomorrow morning through tomorrow
afternoon, due to the warm air advection/warm front that is
expected to move into the area. Could be some MVFR cigs/clouds
late morning, but think scattered clouds with VFR cigs by
afternoon should be good. Winds will be northwest to west tonight
and then become southwest tomorrow.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...Auten
SHORT TERM...Geelhart
LONG TERM...Bak
AVIATION...Auten




Area Forecast Discussion

National Weather Service Marquette MI

 752 PM EST Sun Jan 29 2017

.SHORT TERM...(This evening through Monday)
Issued at 458 PM EST SUN JAN 29 2017

Water vapor imagery and RAP analysis show a deep trof over
eastern N America downstream of a ridge over western N America.
Despite a shortwave tracking across western Lake Superior and thru
WI today and a deep moisture profile/high inversion per model
data/MQT VAD wind profile (upwards of 8kft w and 10+kft e), LES
has not lived up to the potential indicated by the environment.
Wind field over Lake Superior also indicated enhanced convergence
into far western Upper MI and especially into n central Upper MI
as winds over eastern Lake Superior veered ne while n winds
dominated the central part of the lake. While there have been
frequent bursts of hvy snow, the big negative was that LES never
became organized into well-developed bands which would have
supported much higher snow accumulations. However, in the last hr
or so, bands have started to become more organized over s central
Lake Superior, especially with a band running from just e of STDM4
to Munising. Looks like the area between Marquette and Shingleton
will be the focus for ocnl hvy snow at least for the next few
hrs.

Tonight, Upper MI will be dominated by deep layer qvector
divergence/subsidence ahead of approaching shortwave ridge axis.
Associated sfc high pres ridge axis will move over the w half of
Upper MI overnight. While sharpening anticyclonic flow/falling
inversion base/influx of drier air and backing winds over the w
will diminish/end LES expect perhaps over the Keweenaw, models
show more persistent LES lingering east of Marquette under lake
induced trof/lower 850mb temps around -19C thru 12Z. Low-level
convergence tonight will be enhanced by developing westerly land
breeze flow off Marquette county and easterly land breeze wind
component off Ontario. With more organized LES bands recently
taking shape over s central Lake Superior, the expected
strengthening convergence zone into roughly the w half of Alger
county should support some persistence of these heavier snow bands
tonight, possibly resulting in localized snow accumulations
exceeding minimum warning criteria of 8in/12hr. However, given the
high snow-to-water ratio snow, at least 30 to 1 to possibly as
high as 50 to 1, impacts will not be significant even if snowfall
reaches warning criteria. With this fcst issuance, no changes were
made to expiration times of ongoing lake effect headlines. With
high pres ridge reaching the area tonight, temps will plummet
where skies clear out. Bias corrected CMC which typically is a
superior performer on radiational cooling nights has been showing
mins progressively lower in the last few runs, and now has mins as
low as the mid -teens over portions of the interior w half. Not
so certain low clouds will clear out completely or soon enough for
temps to fall that low, but it is not an unrealistic outcome. For
now, mins were lowered several degrees into the 0 to -5F range in
the interior w half.

As winds continue to back Mon morning, any lingering LES into the
eastern fcst area will shift out over Lake Superior. Attention
then quickly turns to vigorous shortwave now moving onshore over
BC. This shortwave will race ese, reaching the western Great Lakes
Mon evening. For being at a relatively short time range into the
model runs, there are still some fairly large differences in the
models though the differences have narrowed. In general, the
global models, GFS/ECWMF/CMC, depict heavier pcpn staying s of
Upper MI while NAM and NCEP ARW and NMM bring heavier pcpn into at
least in the counties bordering WI. Given the depth of the current
eastern N America trof, it would seem the global models probably
have a better handle on the pattern in keeping system a bit more
suppressed as it tracks e. Increasing waa/isentropic ascent will
spread into the fcst area Mon aftn with snow probably spreading
over all but the far ne fcst area by 00z. With 285K sfc (roughly
700-750mb) showing specific humidity around 2g/kg, could see a
couple of inches of snow in the KIWD vcnty by Mon evening with
steadily lower amounts to the n and e.

.LONG TERM...(Monday night through Sunday)
Issued at 351 PM EST SUN JAN 29 2017

The main forecast highlights are chances for system snow early on,
then turning colder with more seasonable temperatures as we progress
through the week, then LES filling in behind the system snow for a
few days across the west and northwest wind snow belts.

The deterministic runs and ensemble means have come into better
agreement today, with the NAM continuing to trend south with the
clipper system and remaining the outlier. With the strongest warm
air advection/isentropic lift progged to continue just south of the
Michigan/Wisconsin border, the higher snowfall amounts should remain
just south of the border Tuesday night. With flow veering around
to the northwest decreasing the 850-700mb baroclinic zone, this
further suggests heavier snow should remain south. Given the
lingering broad lift overhead expect the system snow to remain
fairly light across much of Upper Michigan. Across southern
portions of the area moderate snow may develop at times, but this
is not expected to last long. North of Lake Michigan, system snow
is expected to be slightly augmented due to lake enhancement.
Further to the west, surface through 850mb flow will veer to the
northwest; therefore, expect lake enhancement to also augment
snowfall amounts. After the main clipper system passes, lingering
surface troughing with embedded shortwaves within west-northwest
flow traversing the area should allow for lingering area wide
light snow to continue on Tuesday. With 850mb flow out of the
northwest, expect lake enhancement of snowfall amounts near Lake
Superior.

Tuesday night through Wednesday as another shortwave digs southeast
across the area, much colder 850mb temperatures will filter south
along with drier mid-level air. This will bring back more seasonable
temperatures with highs in the teens and lower 20s. With the deeper
moisture vacating the region, area wide snow should come to an end,
but the increased cold air advection will allow LES to increase in
coverage and intensity across the west and northwest wind snow belts
through Wednesday.

Wednesday night through Thursday as split flow comes onshore across
western portions of the CONUS and longwave troughing digs across far
eastern Canada, flow will become more zonal and allow for LES to
transition over to the west wind snow belts. Friday through the
beginning of the weekend expect LES to weaken if not diminish in
some locations, especially across the west, as large-scale
subsidence and drier air works eastward in the region. Towards the
end of the weekend medium-range models bring another system through
the region, but still quite a bit of uncertainty that far out with
the ECMWF digging much stronger energy south than the GFS.
&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 713 PM EST SUN JAN 29 2017

Expect improving conditions tonight as large scale
subsidence/approaching sfc high pres ridge works to diminish snow
showers, which should result in prevailing MVFR conditions at all
terminals. As winds back from w to e across the area with passing
sfc high pres ridge, low clouds/MVFR cigs will clear out at
KIWD/KSAW late tonight and at KCMX early Mon morning. VFR
conditions won`t last too long though as another low pressure
system sliding to our south spreads snow and IFR conditions into
KIWD Mon afternoon and lowers cigs to MVFR at KCMX and KSAW late
in the day.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 351 PM EST SUN JAN 29 2017

North winds 15 to 25 knots will diminish in speed tonight and back
around to the south through the day on Monday as a clipper system
approaches the area from the north. South winds will increase in
speeds as the pressure gradient strengthens Monday afternoon into the
overnight hours to around 20 to 25 knots. With the clipper system
expected to track just south of the Upper Michigan, the northern
edge of the surface trough will traverse the lake and allow winds to
decrease in speed and become northerly into the day on Tuesday.
Behind this system, expect winds to increase to around 20 knots.
Wednesday through the end of the week, winds will back to the
northwest and further increasing to 25 to 30 knots as cold air
advection increases across the lake and allows for better mixing.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
  Lake Effect Snow Advisory until 7 AM EST Monday for MIZ006-085.

Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...Rolfson
LONG TERM...Ritzman
AVIATION...Voss
MARINE...Ritzman




Area Forecast Discussion

National Weather Service Nashville TN

 739 PM CST Sun Jan 29 2017

.UPDATE...
FOR EVENING DISCUSSION.

&&

.DISCUSSION...

Latest radar imagery shows bands of light snow showers, with some
light rain mixed in along the I-24 corridor, continue spreading
southeast across the northeast half of the cwa. 00Z OHX sounding
indicates the wet bulb zero height has fallen to 478 feet, so
majority of precip from here on out will be simply snow. HRRR
model indicates vast majority of snow will come to an end in the
04-06z timeframe, so will keep Winter Weather Advisory going until
expiration. Could see an additional dusting up to 1/2 inch of
snow on the Plateau in the advisory area this evening. Icy and
slick roads, especially bridges and secondary roadways, will also
become an increasing concern as the night progresses - mainly in
the advisory area where temperatures will fall into the 20s.
Forecast pretty much has all this covered and only made tweaks
based on latest obs and radar.


&&

.AVIATION...
00Z TAF DISCUSSION.

Flying conditions will improve over the taf period. Best moisture
axis has shifted east of CSV but lingering low level moisture and
orographic lift will allow for snow showers to continue for CSV
for the next few hours. HRRR shuts snow down by 03z but a few
flurries could be possible after that for CSV. For BNA and CKV,
tafs should stay VFR for the entire period. CSV should eventually
become VFR by early morning. Westerly winds will be in the 5-10 kt
range. Winds will begin to back to the south late in the afternoon
tomorrow.


&&

.OHX WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight CST tonight FOR
Cumberland-Fentress-Overton-Pickett-Putnam-White.

&&

$$

DISCUSSION......Shamburger
AVIATION........Reagan