Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/23/18
Area Forecast Discussion
National Weather Service State College PA
722 PM EST Mon Jan 22 2018
.SYNOPSIS...
A potent area of low pressure moving across the Great Lakes will
push a trailing cold front through the Commonwealth on Tuesday.
Temperatures will stay above normal into early Tuesday, before
falling back to near or slightly below normal Wednesday and
Thursday. Dry weather is expected for the second half of the
week. The temperatures will rebound to above normals by the
weekend.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Regional radar mosaic at 23Z shows light precip associated with
WAA and 850mb baroclinic zone lifting north of the state, while
band of showers associated with approaching cold front remain to
the west. Latest HRRR and earlier HREFV2 indicate showers will
overspread the Allegheny Plateau between 02Z-04Z, then reach the
Susq Valley by 06Z-07Z.
A marginally unstable air mass, combined with strong forcing
along cold front, could produce some briefly heavy downpours and
thunder late tonight. Based on latest operational model output,
and earlier ensembles, will maintain POPS of near 100 pct tonight.
23Z surface analysis shows quasi-stationary front remains hung
up along the spine of the Appalachians with little movement
anticipated overnight. Based on this, and low dewpoint
depressions, will go with nearly steady temperatures overnight.
Have added mention of patchy fog across the northeast portion of
the forecast area this evening based on current observations.
However, arrival of rain and an increasing breeze should scour
out the fog in the valley locations late tonight.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
Model consensus pushes the cold(occluded) front through the
eastern half of the forecast area between 12Z-15Z. Will maintain
a near 100 pct chance of showers and possible thunder in this
area early in the day, then rapidly lower POPS as drier air
works in behind the front. Breaking clouds expected by
afternoon over the eastern half of the forecast area, as
surface ridging builds into the region. However, upslope flow
is likely to cause stratocu to linger over the Alleghenies and
passage of upper low across the eastern Grt Lks is likely to
spread snow showers into the northwest mountains late in the
day.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
Cold front and low pressure system will be lifting into New
England by Tue night, with secondary front bringing colder air
back into PA - along with snow showers in western sections that
will taper off by Wed night (after only amounting to an inch or
two). Breezy winds up to 30 mph will also impact central PA
during that time as temperatures fall back to seasonal levels.
Thu and Fri will be cooler as high pressure moves across the
region. Eastern areas especially will see chilly mornings as dry
air/low dewpoints associated with the high will be in place.
Progressive pattern will bring moderating temperatures back for
the weekend ahead of another low pressure area. Chances for rain
increase heading into Sunday, followed by a return of cooler
weather and snow showers behind a cold front Monday.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
Wind speed will increase aloft as a strong low level jet noses
in and intensifies over PA. SSW wind at 2-3kft will peak around
55KT late tonight. A cold front will push through around sunrise
in the W, and early aftn in the E. There will be occasional
SHRA through the night, and the wind will be generally light
through the night. IFR will likely be limited to inside the
showers. There is a very small chance of TS in the area
overnight, and in the SE Tues before 18Z. Have not mentioned it
in the TAF yet due to low confidence of occurrence. Expect the
LLWS to not go away until CFROPA, then mechanical mixing will
make it very gusty on Tues. The highest gusts will be at JST.
Cold air will turn the lingering SHRA over the W in the aftn to
SHSN. SCT SHSN will then continue over the high terrain of the
west into Wed.
Outlook...
Wed...AM shsn possible w mtns.
Thu-Sat...No sig wx expected.
&&
.HYDROLOGY...
After coordination with local officials, some concern does still
exist for minor flooding along and near the Susq between York
Haven and Safe Harbor. Therefore, the Flood Watch for this area
has been extended into Tuesday afternoon. Due to the mild
temperatures, there is a potential for ice movement, but there
will also be deterioration/thinning of the ice through time.
All locations along rivers and streams that have significant ice
buildup should monitor water levels closely.
The anticipated rainfall totals of 0.5 to 1.0 inches over the
next 48 hrs is much less than we had a few days ago, and the ice
is less pervasive/extensive due to our relatively mild temps
(versus the period leading up to our previous significant
rainfall). So, no other areas will be placed into Flood Watch at
this time.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Tuesday afternoon for PAZ065-066.
&&
$$
SYNOPSIS...Dangelo
NEAR TERM...Fitzgerald
SHORT TERM...Dangelo/Fitzgerald
LONG TERM...Lambert/RXR
AVIATION...Dangelo/Tyburski
HYDROLOGY...Ross
Area Forecast Discussion
National Weather Service Duluth MN
824 PM CST Mon Jan 22 2018
.UPDATE...
Issued at 821 PM CST Mon Jan 22 2018
Heavy snow continued through the evening commute, but radar trends
over the last hour indicate the precipitation was definitely
diminishing across northwest Wisconsin. As expected, snowfall
amounts across the advisory/warning area were highly variable.
In general, we should see an inch or less in the western areas,
and another 1 to 3 at most in the east. The 23Z HRRR seemed to
have a good handle on the current trends. Will likely continue the
headlines through the current advisory/warning end time.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 332 PM CST Mon Jan 22 2018
The forecast remains on track regarding the winter storm moving
through the Northland this afternoon and tonight. As of 3 PM this
afternoon, surface low pressure was centered over southern Iowa
with a closed 500 mb circulation over northern Missouri. This
storm system will move eastward across southern Wisconsin and into
southern Lower Michigan by late tonight. A broad band of snow
stretched from eastern Nebraska and northeast Kansas north into
southwest Minnesota and then east across the Twin Cities Metro and
into central and northwest Wisconsin. Snow rates of 1 to 2 inches
per hour have been reported over portions of southern and east-
central Minnesota this afternoon. A strong frontogenetically
forced band of snow stretched from the Twin Cities to near
Phillips, WI and was rotating northward. A period of heavy snow is
expected as this band lifts northwestward across Sawyer and Price
Counties and southern portions of Washburn, Bayfield, Ashland and
Iron Counties. The frontogenetic snow band is expected to pivot
and then pull east-northeastward with two periods of heavy snow
possible. Periods of near-whiteout conditions are possible,
especially on ridgetops and hill crests. Widespread visibility of
one-half to one-quarter mile are expected where conditions are
less windy. Additional accumulation over the afore mentioned areas
of 2 to 6 inches are expected through 6 PM, with another 1 to 4
inches by midnight.
To the north and west of the snow, a mix of light snow and
freezing drizzle continues. Sensible heat and moisture flux from
Lake Superior continues to support shallow convection and
convergence, resulting in bands of snow. Outside of those
convective and convergent bands, precipitation rates are lower and
the column profiles indicate freezing drizzle. Look for the
freezing drizzle potential to diminish this evening as the column
cools, changing over to all light snow before ending.
Snowfall totals and placement are largely unchanged from this
morning with a swath of 8-12 inches across southeast Sawyer and
all of Price County, and lower totals farther northwest. No
changes to headlines with the afternoon update as the advisory and
warning areas seem well placed.
.LONG TERM...(Tuesday night through Monday)
Issued at 332 PM CST Mon Jan 22 2018
The Northland is looking at relatively quiet weather for much of
the rest of the week. Weak surface high pressure will move through
the region during the middle of the week, and an upper-level
ridge will build into Northland by late Thursday. This upper-level
ridge will bring a plume of warmer air into region, resulting in
a period of milder weather. The Northland could get a relatively
warm day late this week depending on the timing of when this wave
of warm air moves through the Northland. It currently looks like
the timing of when the axis of warmest air will likely pass
through the Northland Thursday evening or early Friday, rather
than during the day Thursday or Friday. If it would pass through
during the daytime, then the warmer air combined with a little
sunshine could really mean a warm day in the 40s. The GFS`s timing
is about 6 to 12 hours faster than the European and Canadian
model runs, but all three have the axis timing through the
Northland Thursday night or early Friday.
A Canadian Clipper will be on the heels of this plume of warmer
air. This Clipper will likely pass near or just north of the
Canadian border Friday and Friday night, and it will bring light
and snow through the Northland Friday and Friday night. Lingering
snow flurries and cold, blustery winds are possible Saturday and
Saturday night. This latest wind forecast does not reflect these
blustery, gusty winds because of timing differences between the
models generating a blend of overall weaker winds. The GFS is much
faster bringing in the cold air into the Northland than the
Canadian and European. We will likely increase the wind forecast
once we better determine when that surge of Arctic air comes into
the Northland, with widespread gust potential of 20 to 30 mph.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 533 PM CST Mon Jan 22 2018
Widespread MVFR conditions are expected across the Northland
overnight and into early Tuesday. Snow will continue across
northwest Wisconsin this evening, with MVFR to IFR CIG`s and
VSBY`s at KHYR through the evening. The remainder of the region
will see MVFR CIG`s, but some improvement is expected as the night
wears on, as drier air is pulled in from the northeast. The result
will be VFR to MVFR conditions during the latter part of the
night, which will give way to largely VFR conditions on Tuesday
morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 10 23 10 24 / 10 0 10 10
INL -2 17 4 24 / 0 10 10 10
BRD 14 25 13 27 / 10 10 10 0
HYR 18 27 7 26 / 100 10 0 0
ASX 20 24 9 25 / 90 50 10 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning until midnight CST tonight for WIZ003-004-
008-009.
Winter Weather Advisory until midnight CST tonight for WIZ001-
002-006-007.
MN...None.
LS...None.
&&
$$
UPDATE...DAP
SHORT TERM...Huyck
LONG TERM...Grochocinski
AVIATION...DAP
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1017 PM EST Mon Jan 22 2018
.SYNOPSIS...
A moist cold front will move across the forecast area later tonight
and tomorrow morning. In the fronts wake, dry high pressure will
overspread the region and persist into the weekend. Another moist
cold front will affect the region over the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1000 PM: Water-vapor imagery shows a partially occluded
cyclone centered over Illinois. The cold front associated with this
system extends south thru the lower Ohio Valley, middle TN, and
AL, as evidenced by slight wind shift and dewpoint gradient. Over
our CWFA, a fairly contiguous area of showers is being forced
by upper divergence and DPVA, with additional enhancement due
to brisk southerly low-level flow. Updated overnight PoPs using
latest CAM output as a guide. In particular the HRRR continues to
advect the current activity to the NE. With continued moist flow,
dewpoints keep rising overnight over the Piedmont, and this leads
to development of SBCAPE in the early morning hours, per NAM and
RAP. As we have been messaging for several days, this is concerning
given the robust LLJ and associated low-level shear parameters. SPC
suddenly placed focus on our area with a Marginal Risk on the
evening Day 1 outlook update. It certainly can`t be ruled out
that a few isolated Broken-S type structures could develop along
the sfc cold front when it arrives. That said, over the past few
cycles the CAMs have been depicting only disorganized activity
with the front. Also the HRRR has nearly zero SBCAPE.
Winds within the LLJ may produce some problems above 3500 ft. Day
shift extended the advisory to 11z in collaboration with neighbors;
that product will be updated shortly. Temps will be elevated
overnight under clouds and strong LLVL WAA; revised values are
based on short-term consensus product and reflect steady temps in
the east, and onset of CAA in the west.
On Tuesday, there will be a brief window of strong gusts right
behind the fropa, as 925 mb veer to SWLY and remain in the 35-40 kt
range with CAA. This looks to be around daybreak, then winds should
subside a bit and continue to veer to NWLY by late morning. Some
sort of Wind Advisory may be needed in the mountains and possibly
in the piedmont early Tuesday, if guidance trends stronger with the
llvl winds. For now, will let the later shifts assess the threat
and make a decision. By the aftn, skies will clear out, except
right along the TN border, with NW flow bringing some wrap-around
moisture. A slight CHC PoP for ra/sn showers returns by the end
of the day. Temps will be noticeably cooler in the high terrain
with the CAA, while the Piedmont should remain above normal with
help of downslope warming.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 135 PM EST Monday: A weak short wave crosses the area Tuesday
night as the upper low moves NE across New England. A stronger short
wave moves into the area Wednesday then east of the area Wednesday
night. Heights rise Thursday as a ridge axis moves east toward the
area. At the surface, a moist northwesterly upslope flow remains
over the mountains Tuesday night. The pressure gradient slowly
relaxes as the cold front moves east of the area and high pressure
to the west slowly moves east. This keeps clouds and scattered to
isolated snow showers along the TN border with clearing skies
elsewhere. The clouds will linger across the mountains and perhaps
some isolated snow showers along the TN border of the northern
mountains Wednesday as the second short wave moves through. Do not
expect any significant accumulation with these snow showers, but
cannot rule out up to an inch across the highest elevations of the
northern mountains. May even see some of the clouds break
containment and spread across the foothills and piedmont during the
day. Windy to breezy conditions will continue across the mountains
with breezy conditions developing on Wednesday elsewhere. Lows
Tuesday night and highs Wednesday will be near to slightly above
normal.
Winds, clouds and any lingering isolated snow showers diminish
Wednesday night with sunny skies expected Thursday as high pressure
builds in from the west. Lows Wednesday night drop a little below
normal while highs Thursday remain nearly steady near or a little
above normal.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 225 PM Monday...the extended fcst begins at 00z on Friday
with a fairly progressive upper-lvl pattern expected thru the period.
By early Friday, heights will be rising over the fcst area as a
broad upper trof moves off the Atlantic Coast and steep upper
ridging moves over the Eastern CONUS. The ridge will be short
lived and is expected to translate offshore early Sat as another
upper trof moves across the Great Lakes later on Sat and into
Sun. The trof axis will likely move north of the fcst area by
late Sun and then possibly amplify again on Monday to end the
period. At the sfc, expansive high pressure will be in place
over the region to start the period. By late Fri/early Sat, the
high will be drifting offshore putting the CWFA back under
warmer, SLY low-lvl flow. At the same time, a cold front will
be approaching the fcst area from the west. The latest model
guidance suggests that the fropa will occur on Sunday with the
ECMWF being the slower solution. By roughly 12z Monday, things
should be drying out as high pressure spreads back over the
area.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Mainly low VFR to MVFR cigs begin the
period. An upper disturbance will swing over the terminals this
evening, bringing a period of rainfall. The rain is expected to
bring temporary vsby restrictions and should usher in IFR cigs. IFR
is expected to linger until a cold front sweeps through in the
morning, leaving mostly clear skies. Strong flow is already present
above the PBL and it is possible some of the overnight showers
will bring down gusts above 20 kt. Occasional rumbles of thunder
are not out of the question but appear too isolated to mention in
TAFs. Once the front clears, veering winds look likely to bring more
frequent gusts, likely being stronger than what occurs overnight.
Outlook: Dry high pressure will dominate the area through the
remainder of the week. Another system will move in over the weekend,
bringing another round of -SHRA and restrictions.
Confidence Table...
03-09Z 09-15Z 15-21Z 21-00Z
KCLT Med 66% Med 78% High 86% High 100%
KGSP Low 59% Med 76% High 100% High 100%
KAVL High 88% High 83% High 100% High 100%
KHKY Med 71% High 81% High 100% High 100%
KGMU Med 62% High 85% High 100% High 100%
KAND Med 76% High 80% 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...Wind Advisory until 6 AM EST Tuesday for NCZ033-048>053-058-
059.
SC...None.
&&
$$
SYNOPSIS...JPT
NEAR TERM...ARK/Wimberley
SHORT TERM...RWH
LONG TERM...JPT
AVIATION...Wimberley
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
804 PM CST Mon Jan 22 2018
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Evening update discussion:
The previous forecast for tonight is basically on track. Surface
pressures continue to slowly increase in the wake of the cold
front that came through earlier today with all precipitation well
clear of the area. Surface winds will have a tough time decoupling
through the night on the bottom fringes of winter storm affecting
the Midwest and these winds will prevent optimum radiational
cooling from occurring in most areas. Also, there is a band of
higher cirrus running from southwest to northeast over the Pine
Belt currently and this band will have a tendency to "back up"
further toward the heart of the region through tomorrow morning,
generally preventing totally clear skies in many areas through the
entire night. Not sure these clouds will be thick enough to
further hurt radiational cooling potential, but they will not help
it out either. Anticipate lows by morning to mainly range from
the upper 30s to lower 40s, although some spotty mid 30s cannot
be ruled out in typically colder spots that consistently manage to
radiate most affectively. /BB/
Prior discussion below:
Tonight through Tuesday: Latest rap and satellite analysis showed
the upper trough moving into the Mississippi Valley from the Plains.
The cold front was tracking across our eastern counties with the
rain east of the forecast area. Readings across the region were in
the 60s.
For the period expect quiet conditions as the upper trough axis
exits to the east as we get into a zonal flow pattern on Tuesday.
Surface high pressure will build in from the Southern Plains.
As far as temperatures are concerned in the wake of the front
under clear skies we will dip back down into the 30s for tonight
with highs in the 50s on Tuesday./17/
Tuesday night through Sunday:
Zonal mid level flow pattern through much of the week will give
way to ridging from the west by Thursday. This should keep
temperatures relatively cool through a good portion of the week
with a gradual warming trend ensuing by late week. Meanwhile,
another storm system will begin strengthening over the
Intermountain West.
The models differ from this point forward. While the GFS/Canadian
have backed off on the strength of this system as it pulls into
the Plains Friday, the ECMWF still maintains better amplification
and thus better forcing as its attendant cold front moves into the
area Saturday. At the moment will lean toward the more consistent
amplified ECMWF. Despite the differences in the models, a strong
signal still exists in all model solutions in that a large
convective area will develop along the LA/MS Gulf Coast. This
continues to manifest itself further north in our forecast area
with run to run lessening with overall QPF. This is understandable
in the less amplified GFS/Canadian, but the better forced ECMWF
is also showing this. Will have to watch this trend in later
cycles and possibly back off on POPs/QPF if the trend
continues./26/
&&
.AVIATION...
00Z TAF discussion:
Expect VFR conditions through the period with only a few high and
thin cirrus clouds (based above 20 kft) streaming across the
region between now and tomorrow. Surface winds are currently from
the west to southwest at 5 to 10 kts and will remain this way
through the night. Tomorrow, expect winds to transition more to
the northwest and be near 10 kts with occasional gusts up to 20
kts not out of the question. /BB/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 39 58 33 56 / 0 0 2 2
Meridian 39 58 31 57 / 0 0 2 2
Vicksburg 37 59 32 56 / 0 0 2 2
Hattiesburg 40 62 35 58 / 0 0 2 1
Natchez 38 61 32 56 / 0 0 2 2
Greenville 37 56 32 53 / 0 0 2 1
Greenwood 37 54 30 53 / 0 0 2 2
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
17/26/BB
Area Forecast Discussion
National Weather Service Louisville KY
903 PM EST Mon Jan 22 2018
.Forecast Update...
Issued at 900 PM EST Mon Jan 22 2018
Most of the cells across the region are not bringing down stronger
winds, with just a few showing pea-sized hail and one that got tall
enough for a warning. The back edge of the precip is where the
strongest winds have been so far this evening, with gusts around 50
mph at FTK, SDF, and LOU in the last hour. There must be just enough
of a mix down occurring along that back edge to allow some of the
stronger winds aloft to get down to the surface. Otherwise, the
automated gauges and Kentucky Mesonet sites are not showing stronger
winds at this time. Will have to continue watching storms along this
back edge for any rotations, as that would bring a better chance to
get it to the surface.
Issued at 655 PM EST Mon Jan 22 2018
Line of showers and a few thunderstorms embedded forming a little
farther west than the HRRR anticipated. The NAMNest, which has been
doing a great job in the near term the last several weeks, has
picked up on the location better, and thus have leaned toward this
model in the near term, as well as current observations from radar.
Environment appears supportive for some low-topped supercells, and
have seen a couple form along our western forecast area, near
Lewisport, KY and Tell City, IN. Have seen some good rotation with
these storm, and will continue to monitor trends. Otherwise, seeing
wind gusts of 30-40 mph out there, and we may see a few storms with
stronger gusts the rest of this evening.
&&
.Short Term...(This evening through Tuesday night)
Issued at 301 PM EST Mon Jan 22 2018
...Gusty Showers Expected This Evening...
GOES East imagery shows an impressive and mature cyclone over the
upper Midwest. Today`s widespread rainfall associated with the warm
conveyor portion of the cyclone has continued to weaken as it pushes
east, however still expect everyone to get some rain so likely to
categorical pops continue east of I-65 for another couple of hours.
The focus then shifts back to the west as an impressive dry slot
begins to work into western KY. Hi-res models have been pegging
redevelopment of showers (and perhaps an isolated T) somewhere along
or W of I-65 late this afternoon and early this evening. This would
occur as the approaching cold front (still back over the mid
Mississippi River Valley) combines with exit region dynamics to kick
of sct-numerous showers. Given that the low level jet will still be
around 45-50 knots, worried that the steepening lapse rates will
help some stronger gusts get down to the surface with the showers.
At this point, thinking some Special Weather Statement worthy gusts
of 40+ mph are possible. Still not all that confident on exactly if
the showers will redevelop to the magnitude that the HRRR shows, but
if they do am more confident that we will see some pretty healthy
gusts. Think this would be better handled by short fused SPS`s than
any Wind Advisory product given the expected convective and short-
lived nature. Still, synoptic winds outside of any showers could
still gust up to 35 mph through the overnight.
Later tonight, low level moisture associated with the comma head of
the mature cyclone moves into our CWA, with deep enough moisture to
squeeze out some measurable light showers and sprinkles, mainly
across our northern CWA. Temps fall off into the upper 30s and low
40s through Tuesday morning, but think thermal profile stays warm
enough for rain. As we move deeper into the day on Tuesday, will
continue to keep low chances for a measurable shower and/or
sprinkles. Also think we could see a few ice pellets mix in given
some positive area (steep low level lapse rates) extending well
above the freezing level.
Low level moisture still looks to linger into Tuesday night where
temp profiles begin to be cold enough to possibly support some
flurries. Lows should drop into the mid and upper 20s.
.Long Term...(Wednesday through Monday)
Issued at 301 PM EST Mon Jan 22 2018
Wednesday - Friday...
A secondary shortwave will slide through on Wednesday. Low level
moisture should remain trapped through this time, so added ascent
from the passing shortwave could be enough to kick off some
continued flurries or sprinkles. Will keep a dry forecast (from a
measurable standpoint) but may have to mention chances for a
sprinkle or flurry through Wednesday night. Highs should struggle
into the low 40s.
Dry NW flow aloft and surface high pressure will then dominate
through Thursday night, keeping us dry with steadily moderating
temperatures. Highs by Thursday will be in the upper 40s to low 50s.
After Wednesday night lows in the mid 20s, Thursday night lows
should trend milder to around freezing.
Progressive upper ridge axis slides through on Friday, and will
bring another dry and warmer day. Look for highs in the mid 50s.
Friday Night - Saturday Night...
Models have trended less amplified and faster with the weekend
system, which will bring shower chances in by Friday night. The bulk
of the rainfall should be on Saturday as deeper moisture pools ahead
of the upper trough axis, along the surface cold front. Given the
faster and less amplified trend, it`s going to be harder for any
cold air to catch up to lingering moisture on the back side of the
system. So, think a mostly rain forecast is still the way to go.
After a milder Friday night in the mid 40s, Saturday highs will also
be in the mid 50s, with temps falling off Saturday night behind the
front.
Sunday - Monday...
Dry NW flow and surface high pressure then control for the remainder
of this forecast cycle. Slightly cooler temps take hold with lows
just below freezing and highs in the 40s.
&&
.Aviation...(00Z TAF Issuance)
Issued at 620 PM EST Mon Jan 22 2018
Have some pretty gusty winds out there now, as a potent low pressure
system drags a cold front across the region. Also seeing a few
showers pop up with some isolated thunder. This rain will not last
long, but we could see some gusts to 35 knots either with or without
the rain. A clear slot will come behind these showers before we
should get socked in with lower clouds by daybreak Tuesday. For now
time-height sections indicate these should stay MVFR, but that they
should persist through the rest of the day. Wind gusts will persist
through the period as well.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...RJS
Short Term...BJS
Long Term...BJS
Aviation...RJS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
924 PM CST Mon Jan 22 2018
.UPDATE...
924 PM CST
The main forecast concern for later tonight is the potential for
a band of snow to develop across portions of far northern IL into
early Tuesday morning.
Water vapor imagery early this evening indicates that the main
mid-level circulation is now beginning to shift northeastward
into far west-central IL (just north of Quincey, IL). The surface
low over eastern Iowa has become occluded over the past several
hours, with a new center of low pressure now developing over far
northeastern IL and southeast WI this evening. Given the occlusion
of the main storm system, a well defined TROWAL (TRough Of Warm
Air Aloft) structure has developed to the north of the main
circulation into southern WI. Ultimately this is setting up prime
conditions for the development of a rather intense area of mid-
level frontogenesis along the southern periphery of this TROWAL
where mid-level deformation is strengthening in association with
the arrival of the mid-level low. Radar trends across far northern
Illinois and far southern Wisconsin already indicate that this
process is underway as a nearly stationary band of precipitation
resides.
The main concern is that as dynamic adiabatic cooling continues
and colder air begins to wrap back into northern IL tonight that
this will result in the change over to a band of potentially heavy
snow into early Tuesday morning. Overall confidence on the trends
of this change over to snow remains low at this time, but guidance
indicates that the column should become sufficiently cold to
support a change over to snow around midnight over northern IL.
Given the presence of steep mid-level lapse rates above the
TROWAL, heavy snow will be possible across far northern IL later
tonight. The main question that remains is how much snow will
fall. There certainly is the potential to get a quick few inches
of wet snow near the WI state line, but amounts would likely
rapidly drop off to the south towards the I-88 corridor. I tossed
around the idea of putting an advisory up for my far northern
counties, but have opted to hold off for now and go with a
special weather statement. Given the potential impacts to the
morning rush, an advisory could be needed later tonight.
Given the above, I have increased snow amounts far north to around
2-3 inches, with a change over to snow expected around, or shortly
after midnight.
KJB
&&
.SHORT TERM...
200 PM CST
Through Tuesday...
Low pressure is centered near Des Moines, Iowa this afternoon with
a warm front draped across far northern Illinois. In the
vicinity of the front, fog and drizzle will continue this
afternoon across far northern Illinois while farther south dry air
wrapping in from the southwest has allowed partial clearing west
of the I-57 corridor. Temperatures and dew points are into the
upper 40s to low 50s within the warm sector and are superimposed
by steep low to mid level lapse rates this afternoon which are
contributing to a corridor of seasonably strong instability.
Midday soundings from DVN and ILX show MLCAPE values around 150
J/kg while SBCAPE is closer to 600 J/kg. Latest run of the RAP
picks up on this axis of instability and shifts it east across the
CWA through the late afternoon and early evening ahead of an
advancing cold front, albeit with weakening instability as we get
past peak heating. Very strong winds aloft with 0-1km shear in
excess of 20kt and favorable effective SRH continue to prompt some
concern for a severe threat for any thunderstorms that make it
into the area this afternoon and evening, and an isolated tornado
remains a possibility. Convective initiation is already ongoing
near Springfield, IL with agitated cu field south towards St
Louis. These storms will move north-northeast through the late
afternoon and evening hours within the aforementioned instability
axis though confidence in how well they will maintain their
intensity is fairly low by the time they reach the local CWA.
Late this evening and overnight, 500mb closed low will move across
the region and allow deeper moisture to return resulting in
periods of light rain. Forecast soundings eventually cool enough
for precipitation to transition to snow during the predawn and
early morning hours Tuesday. Models have been fairly consistent
showing axis of highest QPF near and north of the IL/WI state
line. As precipitation changes to snow, could see a dusting/few
tenths of snow area-wide, but the best chance for any light
accumulations will be across the northern tier of counties where
up to an inch of snow is possible. Winds turn northwest behind
the departing low Tuesday morning and mid level moisture scours
out once more. Steep low level lapse rates redevelop in the
northwest flow and could result in a few additional flurries
during the late morning and afternoon. Temps will fall into the
low to mid 30s behind the cold front tonight and likely hold
fairly steady through the day tomorrow.
Deubelbeiss
&&
.LONG TERM...
140 PM CST
Tuesday night through Monday...
Closed upper low continues to pull away from the region Tuesday
evening, with mid-level short wave ridging building briefly across
the area early in the night. Partial clearing of lower clouds is
possible during the evening in response to mid-level drying and
subsidence associated with strong H5 height falls (nearly 150
meters), though forecast soundings depict redevelopment of mid-
level clouds overnight as another mid-level short wave quickly
approaches. Clouds linger through the day Wednesday as the wave
propagates across the region, with a weak surface cold frontal
trough. Model soundings depict a relatively dry 900-700 mb layer
however, which suggests little precip threat despite cloudy skies.
Model 950 mb temps generally support daytime highs in the low-mid
30`s.
Mid-level short wave and larger scale upper trough axis moves
east of the area Wednesday night. Medium range guidance is in good
agreement in building broad upper ridging east across the region,
with dry and milder conditions Thursday and Friday. Pattern is
progressive, with an upper trough developing eastward across the
central and northern Plains, and an area of surface low pressure
which tracks into western Ontario and trails a cold front through
the local area Friday night or early Saturday. Surface high
initially blocking gulf moisture return, and relatively quick
progression of upper flow, suggests somewhat limited precipitation
potential, especially with quicker cold frontal passage depicted
by the GFS. Slower ECMWF/GEM solutions would support a little
greater potential for rain especially across the southeastern part
of the cwa into Saturday. After 40`s Thursday, and temps likely
near 50 Friday, timing differences with the cold front add lower
confidence to the high temp forecast Saturday, with 45-50 degree
highs likely east/southeast of the advancing front.
Colder air spreads back in behind the front Saturday night,
though by the time precipitation ends in the southeast, model
partial thickness values would suggest precip type would likely
remain all rain. By Monday, even the slowest guidance (ECMWF)
moves the upper trough east of the area, with broad upper ridging
moving in aloft with weak high pressure ridge at the surface. Some
detail differences exist as expected by that time, though
generally it appears our colder air will result in temps around
average for late January. Pattern looks to remain progressive as
well, with milder air again early-mid next week.
Ratzer
&&
.AVIATION...
For the 00Z TAFs...
Several forecast concerns/challenges this forecast period:
* Showers and Thunder this evening
* A band of light/moderate, possibly heavy, snow tonight thru Tue
AM
* Returning IFR ceilings, with LIFR possible
* Wind shift to the northwest Tue AM
* Continued scattered snow showers Tue
Latest radar imagery showing area of showers and thunderstorms
continuing to move across much of northern Illinois. RFD currently
being impacted but expect the remaining terminals to see this
precip over the next hour, with thunder still a possibility.
However, ORD/DPA have the highest chances of observing this
thunder along with a possibility of small hail. Showers will then
linger for 2-3 hours but should diminish in coverage after that
point, while conditions remain mainly VFR. The arrival of colder
air and stronger forcing later tonight will support a window of
light to moderate snow, and have adjusted TAFs to account for
latest trends. This will start earlier at RFD, but then spread
east southeast soon there after. Have higher confidence of snow
now occurring, but do think there could be a window of heavier
snow. Have lowest vis falling to 1sm, but vis below 1sm is
possible. Will need to monitor this period and potential snow,
especially as snow accumulation will be possible at the terminals.
Ceilings will fall under this snow, with IFR a definite
possibility. LIFR will also be possible. Conditions should improve
by early Tuesday morning, but with winds shifting to the
northwest and with periodic snow showers continuing throughout the
day.
Rodriguez
&&
.MARINE...
155 PM CST
Main marine forecast concerns focus on deep area of low pressure
which will move across southern Lake Michigan tonight. In
addition, areas of locally dense fog were in place across southern
parts of the lake, where 40-50 degree dew point air has spread
north over the colder waters. Strong northeast winds currently
occurring across northern parts of the lake will gradually back
northerly and increase more solidly into gale range through early
Tuesday morning as the low moves through, and will increase to
gale strength over the southern portion of the lake Tuesday
morning as the low pulls off to the east. Gale warning headlines
are already up for the north half, though there winds are largely
just below gale force this afternoon. A gale warning is in effect
for the southern part of the lake starting early Tuesday morning,
and headlines for the entire lake will run through 00Z/6 pm CST
tomorrow. A dense fog advisory remains in effect into this evening
on the south end of the lake.
The low will eventually move off across the St. Lawrence Valley
Tuesday night, with weak high pressure ridging spreading across
the western Lakes Wednesday. This will allow winds to diminish to
less than 20 kts, and eventually back to the south-southwest by
early Thursday. Deep low pressure is expected to develop in the
lee of the Northern Rockies Thursday night, which will induce
increasing south-southeast winds. A period of southerly gales is
possible Friday through perhaps early Saturday, after which a cold
front will shift winds to the west.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Dense Fog Advisory...LMZ777-LMZ779 until 3 AM Tuesday.
Gale Warning...LMZ777-LMZ779...3 AM Tuesday to 6 PM Tuesday.
Small Craft Advisory...LMZ740-LMZ741-LMZ742...6 AM Tuesday to 4
AM Wednesday.
Small Craft Advisory...LMZ743-LMZ744-LMZ745...6 AM Tuesday to 10
AM Wednesday.
&&
$$
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Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
910 PM CST Mon Jan 22 2018
.DISCUSSION...See updated information for land and marine areas below.
&&
.UPDATE...Have updated to remove slight chance pops over the
easternmost portion of the area with dry conditions expected for
the remainder of the night. Made other minor adjustments. /29
&&
.MARINE...Have extended the Marine Dense Fog Advisory for the
Mobile Bay area and the adjacent near shore waters until 05Z. A
cold front currently advancing across southeast Mississippi will
move through later this evening and scour out the fog where the
advisory is in effect. /29
&&
.PREV DISCUSSION... /issued 601 PM CST Mon Jan 22 2018/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...Mostly MVFR cigs and visibilities through about
23.04z followed by VFR conditions through 24.00z. A short period
of low stratus and fog will also be possible through 24.04z ahead
of a cold front approaching from the northwest. Winds will be
south to southwest at 8 to 12 knots through about 23.04z shifting
northwest late this evening through 24.00z. 32/ee
PREV DISCUSSION... /issued 535 PM CST Mon Jan 22 2018/
DISCUSSION...See updated information for land areas below.
UPDATE...Have updated to lower pops to slight chance over the
eastern third of the area based on current radar trends and the
latest high resolution guidance. No other major changes. /29
PREV DISCUSSION... /issued 400 PM CST Mon Jan 22 2018/
NEAR TERM /Now Through Tuesday/...Surface analysis indicates that
the surface cold front is making its way into east central MS and
southeast LA. Winds are veering southwesterly to westerly with
dewpoints falling into the 30s and 40s behind the boundary. The
front is entering our far northwestern zones as of 3 PM, with clouds
beginning to decrease over Wayne and Choctaw counties. Overcast
skies and moist southerly flow otherwise persists over much of our
area ahead of the front. Radar indicates convection has become
scattered in nature over much of the region, except for a zone of
better coverage near the northwest FL Panhandle coast. Ascent
associated with the shortwave trough axis will become focused over
the eastern CWA ahead of the approaching front through the rest of
this afternoon, and this is where the best chance of convection will
be through 00z. POPs will meanwhile quickly decrease over western
and northern areas as the front moves across this portion of the
region through late afternoon. We still cannot rule out an isolated
strong storm or two over the eastern CWA through the rest of the
afternoon where residual weak MLCAPE values mostly below 400 J/KG
will persist, but the overall lack of instability will preclude an
organized severe threat.
There could be some patchy fog develop near the immediate coast late
this afternoon into early this evening prior to the passage of the
front. Otherwise, winds will gradually turn west to northwest
following frontal passage late this evening into the overnight hours
with a cooler and drier airmass arriving in the wake of this
feature. Sunny skies and dry conditions are expected Tuesday
underneath dry zonal flow aloft. /21
SHORT TERM /Tuesday night Through Thursday night/...Upper level
zonal flow along with building high pressure will keep conditions
dry and cool through Thursday. Although this airmass will not be
anywhere near as cold as the past few systems. Clear skies can be
expected with temperatures near seasonable levels. /13
LONG TERM /Friday Through Monday/...An upper trough will develop
across the plains and move east late in the week. As this system
approaches, moisture levels will increase across the area as
southerly flow develops. This will bring increasing rain chances
from the west on Friday. Rain becomes widespread Saturday and
Saturday night as an area of low pressure develops and moves east
ahead of the trough. The GFS and ECMWF differ on how strong the
low will and where it tracks as they handle the upper shortwave
differently. The Euro is much more amplified which allows the low
to move across the area Saturday night into Sunday morning.
Meanwhile, GFS has a weaker shortwave and keeps the low track
across the Gulf. We have left thunder out of the forecast for now,
but will be something to watch to see how it develops late in the
period. /13
MARINE...Moist southerly flow over the cool nearshore waters
will maintain potential for areas of dense marine fog over Mobile
Bay, the Mississippi Sound, Perdido Bay, and the adjacent offshore
waters out 20 NM through early this evening. The NAM, RAP, and HRRR
all show continued potential for areas of fog over these areas, with
relatively high probabilities for fog also indicated on the SREF.
Will keep the Dense Fog Advisory in effect for these areas until 9
PM. A drier airmass then arrives with increasing northwest winds this
evening following the passage of a cold front. Winds will be at
advisory levels offshore, so will have a Small Craft Advisory in
effect for the Gulf waters out 60 NM from midnight tonight through 9
AM Tuesday. A moderate to occasionally strong offshore flow will
continue Wednesday and Thursday, before becoming more easterly
Friday and into the weekend. /21
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...Dense Fog Advisory until 11 PM CST this evening for GMZ630>633-
650.
Small Craft Advisory until 9 AM CST Tuesday for GMZ650-655-670-
675.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
554 PM CST Mon Jan 22 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 310 PM CST Mon Jan 22 2018
Water vapor imagery showing upper low drifting slowly e-ne across
northeast MO this afternoon. Enhanced area of clouds now over
southeast MN and is beginning to pivot. Another area of enhanced
clouds drifting into far southern MN where moderate to heavy snow
has been falling much of the afternoon. Strong north/northeast
winds gusting to 35-40 kts at times continue into south central
area, where they have already observed 8 to 12 in the heavy snow
band. Significant blowing and drifting snow with near whiteout
conditions expected to continue through the remainder of the
afternoon in the blizzard warning area. The greater rates have
worked into the southern Metro where 1 to 2 inches an hour will
likely continue through about 6-7 PM. Will likely see around a
foot of snow in Scott and Dakota Co. with 6 to 10 inches likely
across the metro.
The system is forecast to exit to the east this evening and will
continue the headlines through 06Z. An addition 1 to 3 inches
likely accumulating after 6 PM over the southeast area.
Trimmed the highs for Tuesday over the expected heavy snow area
over south central MN into western WI. Otherwise, we should see
more sunshine for Tuesday.
.LONG TERM...(Tuesday night through Monday)
Issued at 310 PM CST Mon Jan 22 2018
The weather pattern will be progressive for the extended period,
however no significant hazardous weather is expected. The shortwave
that is anticipated to pass through overnight Tuesday into Wednesday
morning will keep skies mostly cloudy through Thursday. Temperatures
will become more mild as the week continues as the thermal ridge
builds-in on Thursday and continues through Friday. Temperatures
will be above-normal with highs reaching the lower to mid 40s on
Friday.
This third January thaw will not last long as a cold front will
arrive late Friday into Saturday morning. Depending on the exact
timing of the front, Saturday may be one of those days where the
high temperatures of mid to upper 30s occur close to midnight in the
Eastern half of our CWA. There is a chance for light snowfall late
Saturday into Sunday, primarily over West Central Wisconsin, with an
upper-level trough in place. Temperatures will remain near normal to
slightly below normal on Sunday and Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 554 PM CST Mon Jan 22 2018
Deformation band continues to go strong across the Twin Cities
metro and looking at the HRRR, this band is not going anywhere for
the next 3-5 hours, so delayed improvements toward a hrrr timing
for MSP/MKT/RNH/EAU. After the snow, HRRR and other hi-res models
show a clearing aggressively working south out of northern MN in
the subsidence behind this system. However, the stratus behind
this system goes clear up to the middle of Lake Winnipeg, so went
with the slower timing for cig improvements seen with the GFS
Bufkit profiles and LAV guidance. Monday afternoon we will see
another shortwave coming at us from the Dakotas. LAV shows some
MVFR cigs trying to work back in out west during the afternoon,
but that doesn`t have much support from GFS soundings. Instead it
looks like an increase in mid level clouds.
KMSP...Based on continued high reflectivity in the band just west
of MSP and HRRR forecasts showing this deformation band lingering
through at least 5z, delayed improvements to above 1/2sm in snow
until 4z. This may be a little long, but will watch trends.
Another 2-4 inches of snow is expected before the snow finally
ends.
/OUTLOOK FOR KMSP/
Wed...MVFR/IFR cigs. Winds SW 5 kts.
Thu...Chc MVFR/IFR cigs. Winds SE 5-10 kts.
Fri...Mainly VFR. Winds S-SW 5-15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Warning until midnight CST tonight for WIZ014>016-
023>028.
MN...Winter Storm Warning until midnight CST tonight for MNZ060>063-
067>070-078.
Winter Weather Advisory until midnight CST tonight for MNZ053-
065-066-073.
Blizzard Warning until midnight CST tonight for MNZ074>077-
082>085-091>093.
&&
$$
SHORT TERM...DWE
LONG TERM...AMK
AVIATION...MPG
Area Forecast Discussion
National Weather Service Tallahassee FL
821 PM EST Mon Jan 22 2018
.UPDATE...
Trimmed PoPs across our western areas as HRRR and other Hi-Res
models shifting the highest chances east and current radar
reflects this. Little instability has led to lightning strikes
mainly over the waters and virtually NIL across land areas so have
pulled thunder from the land areas. Highest chances overnight will
be across the eastern third of the CWA plus the coastal waters.
Cold front upstream will make it across most of the CWA by dawn.
Ahead of the front, low clouds and possible fog is possible until
the front passes by.
&&
.PREV DISCUSSION [614 PM EST]...
.NEAR TERM [Through Tonight]...
At 1 pm EST a surface cold front extended southward through eastern
MS, southeast LA, and into the western Gulf of Mexico from a 995 mb
low centered over IA. The mid-upper tropospheric low was positioned
near the surface low, indicating that the low was near maturity.
Ragged bands of showers and thunderstorms preceded this surface
front, and will be moving east across our forecast area later this
afternoon through tonight. While 0-6km bulk shear values suggest
storm organization is possible, poor thermodynamics will make it
difficult to sustain strong updrafts, or for surface-based damaging
wind gusts. So far recent upstream radar imagery and surface
observations bear this out, as there haven`t been any significant
wind gusts where there was organized reflectivity.
For most of our forecast area temperatures will be well above
average, with lows in the mid 50s to low 60s. However, lows in the
upper 40s are expected in southeast AL and the western FL Panhandle,
where the cold front will have moved through before daybreak. Ahead
of the front, areas of fog will be possible, mainly between the time
when the rain ends and the cold front arrives.
.SHORT TERM [Tuesday Through Wednesday Night]...
The cold front will continue sweeping eastward across the
remainder of the forecast area Tuesday, with a cooler, drier
airmass moving in behind it. Temperatures will warm to the 60s
Tuesday, but will struggle to hit 60 Wednesday as the cold air
advection continues. Overnight, temperatures will dip into the
mid-upper 30s Tuesday night, low-mid 30s on Wednesday night.
.LONG TERM [Thursday Through Monday]...
A shortwave upper level trough will lift northeastward from central
Mexico toward the central Gulf coast, helping develop a disturbance
in the western Gulf waters that will move toward the north-central
Gulf coastline. As this system will spend its early life cycle over
the Gulf waters, it`s expected to be very rich in moisture and
bring a decent amount of rain with it. Early estimates from WPC
are around 1-2" accumulations this weekend, with higher rainfall
totals offshore and to our west. The storm will move eastward out
of the area by Sunday night, with a dry start to the following
work week.
.AVIATION [Through 00Z Wednesday]...
Degraded flt conds for the next 12-15 hours with showers across
the area and cigs decreasing to LIFR overnight. A cold front is
located to our west and vsbys will also decrease overnight. Conds
will persist until the cold front moves through at which time flt
conds will return to VFR.
.MARINE...
Winds and seas will be agitated by tonight`s frontal passage and
will remain elevated for the next several days as a low pressure
system develops in the western Gulf and then moves into our
forecast area this weekend. Cautionary conditions are expected the
next few days, with advisory conditions possibly developing
around Wednesday night for our offshore waters.
.FIRE WEATHER...
A few areas could briefly reach locally critical RH values Tuesday
afternoon. However, tonight`s rain and weakening winds on Tuesday
should prevent Red Flag conditions are not expected.
.HYDROLOGY...
Rainfall totals from the approaching cold front will be around 0.5-
1", which is not expected to cause any flooding concerns. This
weekend, we`ll have another chance for rain, this time with higher
rainfall totals expected, around 1-2", which should be welcomed
given our current drought.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 56 68 38 59 34 / 80 10 0 0 0
Panama City 54 63 41 57 39 / 80 0 0 0 0
Dothan 48 64 36 59 33 / 50 0 0 0 0
Albany 52 65 37 60 34 / 70 0 0 0 0
Valdosta 59 66 39 57 36 / 80 20 0 0 0
Cross City 61 70 39 60 35 / 80 40 0 0 0
Apalachicola 57 65 41 57 38 / 80 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...Scholl
NEAR TERM...Fournier
SHORT TERM...Nguyen
LONG TERM...Nguyen
AVIATION...Scholl
MARINE...Nguyen
FIRE WEATHER...Fournier
HYDROLOGY...Nguyen
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Tuesday)
Issued at 301 PM CST Mon Jan 22 2018
Surface low pressure continues to exit northeast Kansas moving
northeast towards the Great Lakes region. Gusty northwest winds
have been seen through the afternoon with gusts around 40mph
observed as a tight pressure gradient is observed over the area.
Light to moderate snow/rain has been falling across north central
Kansas this afternoon making its way east as it rotates counter-
clockwise around the low pressure. The greatest snowfall totals
still look to be in north central Kansas and near the
Kansas/Nebraska border, with amounts just over two inches
expected with locally higher amounts. Advisory has been expanded a
few more hours in time and farther eastward, to capture
additional snowfall amounts in windy conditions that will likely
have some impact on school and work commutes.
Still expect hazardous road conditions and lower visibilities as
this snow falls due to the high wind speeds between 20-25 mph
sustained through midnight. As precipitation moves northeast out
of the area, a changeover to all snow will be seen as temperatures
fall below freezing. Expect all snow to come to an end after
midnight tonight. There could still be some slick spots on any
untreated, wet roads so cautious travel is advised.
Winds decrease overnight as the low departs and lows will fall into
the low to mid-20s. Skies clear from west to east with mostly clear
skies expected shortly after sunrise. Dry conditions will persist
tomorrow with diurnal heating bringing temperatures into the low 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 301 PM CST Mon Jan 22 2018
Weather pattern quiets considerably for the extended period as
temperatures slowly moderate into the late week. A weak passing
shortwave trof Tuesday night shifts winds around to the west then
southwest for Wednesday. After a night of lows in the 20s, highs
rise into the upper 40s, with lows the following night holding in
the upper 20s to low 30s as southwest surface winds continue. By
Thursday and Friday, highs rise into the middle to upper 50s and
lows rise to above freezing by Thursday night. Upper trof that was
more amplified in previous runs of both the GFS and EC for Friday
has dampened, with resulting lesser impact on temperatures and
lower rain chances for late Friday.
Highs progged in the middle to upper 40s for the weekend behind the
passing upper trof, which is still above normal for this time of
year.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 540 PM CST Mon Jan 22 2018
Timing of ending of precipitation and cloud trends are the main
challenges. HRRR is largely in step with with radar trends in
shrinking and weakening of snow as the deep system exits the
central Plains. There is a trend toward a shallow stratus deck
lingering into the last half of this forecast, but too little
confidence in this given upstream observations to extend MVFR
cigs yet.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST this evening for
KSZ008>011-020>023-034>038.
&&
$$
SHORT TERM...Heller
LONG TERM...67
AVIATION...65