Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/18/20
Area Forecast Discussion
National Weather Service Bismarck ND
754 PM CST Fri Jan 17 2020
.UPDATE...
Issued at 701 PM CST Fri Jan 17 2020
Updates made this evening were to cancel both the High Wind
Warning and Wind Advisory. Then a Wind Chill Warning (northwest
North Dakota) and a Wind Chill Advisory (rest of western North
Dakota) was issued. No changes needed to the current Winter
Weather Advisory or upcoming Blizzard Warning.
Currently, radar returns showed two almost distinct areas of snow
in central/eastern North Dakota. Light snow was being reported in
southeast North Dakota including Jamestown under modest
isentropic lift amid a closed 700mb low. Further west, a thin band
of relatively stronger reflectivities stretched from northeast
North Dakota through Wells/Kidder/Emmons counties. This band of
snow has persisted over the past several hours aided by increasing
divergence aloft and mid-level instability within a corridor of
negative EPV. The reporting station in Linton has been reporting
heavy/moderate snow with visibilities at 3/4 to 1/4 miles in the
past several hours under this band. While we increased snowfall
totals in this persistent area of stronger snowfall rates, RAP
guidance shows mid-level instability decreasing through the
evening so while snow will continue under synoptic support aloft,
the stronger rates from this somewhat convective snowband should
decrease. The going forecast of 4-6 inches in the James River
valley looks to be on track as snow will continue through the
night.
1Z surface analysis shows the frontal boundary making its way into
eastern North Dakota, currently drawn from McIntosh north through
Kidder and just west of the Devils Lake basin. With wind gusts of
near 45 knots being reported along and behind the front, blowing
and drifting snow continues to be a concern as the front makes its
way into the James River valley through the evening. Further
west, while peak wind gusts were low enough to cancel the wind
headlines, wind chills will be the concern tonight and thus
advisories/warnings were issued for the night through Saturday.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 230 PM CST Fri Jan 17 2020
Forecast highlights in the short term period will continue to
focus on the winter storm/high wind event associated with a strong
storm system lifting north into the region, followed by a strong
cold FROPA later today and this evening.
Currently, light snow or light freezing drizzle developing across
western and central North Dakota as forcing aloft increases ahead
of a potent mid level trough lifting north across the Central
Plains and Dakotas. Associated sfc trough extends from Adams
county north-northeast through Minot and into southwestern
Manitoba. Embedded feature within the trough will close off over
eastern ND this evening, with a 700mb low tracking north/northeast
across southeastern ND 23-04Z including the James Valley. Earlier
shifts increased snow for this area, and followed this trend with
this forecast issuance, with the James Valley now forecast to
receive 4-6" of snow. First wave will impact the area over the
next few hours, with then wrap around snow bands as the mid level
low closes off and stalls tonight. Farther west, models have been
trending towards a consensus with developing a post cold frontal
snow band on the nose of strongest CAA in the wake of the stronger
pressure rises. By this evening BUFKIT sounding analysis
indicates the atmosphere mainly saturated so feel the freezing
precip threat will be less than what we will see this afternoon.
The current winter weather advisory which goes through 02Z this
evening for my southeast counties remains valid. Accumulating snow
will develop into the advisory area, with gusty southeast winds
slowly tapering off as the sfc trough advances eastward this
afternoon. Farther east counties across the Red River Valley were
upgraded to a blizzard earlier today, as those areas will see a
much longer duration of the stronger southeast winds.
Current wind headlines were left pretty much alone, with the
exception of Grant and Sioux counties that were changed to a
winter weather advisory set to begin at 00Z this evening. More on
that change below. Will see winds ramp up significantly across
southwest North Dakota between 21-00Z as a strong pressure rise
bubble builds into this region. Elsewhere winds will be strong but
not headline worthy.
As the strong CAA and pressure rises push east into central North
Dakota late this afternoon/early this evening, the strong winds
develop eastward and will coincide with the aforementioned post
frontal snow band and existing loose snow cover on the ground to
create vis below 1 mile in blowing snow, especially in open
country and as temperatures drop. Opted to add a 2-tier stretch
of counties to the west of the inherited winter weather advisory
to include all of central ND and parts of western North Dakota,
and will also begin earlier at 00Z to better coincide with the
initial surge of CAA strong winds.
Blizzard warning goes into effect at 02Z, and will make no changes
with this headline. The combination of several inches of snow
combined with 50 mph wind gusts will create life threatening
conditions over the eastern third of the state, and fully expect
numerous travel advisories and road closures (including I94 likely
from Bismarck east) sometime this evening/tonight.
Bitter cold air filters into the region tonight into tomorrow behind
the cold front, and will see wind chill headlines
expanded/upgraded in future forecast issuances. For now stayed
focused on the blowing snow threat.
.LONG TERM...(Saturday night through Friday)
Issued at 230 PM CST Fri Jan 17 2020
Colder but drier weather dominates the weekend with windchill
headlines likely into Sunday. Northwest flow becomes zonal next
week, resulting in a warming trend. Expecting highs to reach into
the 30s for most of the area Tuesday through Thursday. Nothing on
the horizon as far as any precipitation makers in the long term
period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 742 PM CST Fri Jan 17 2020
A significant winter storm will create blizzard conditions across
the James River Valley through 18Z Saturday. IFR to Very Low IFR
with wind gusts to 45 KTS expected at KJMS through 18z, with
gradually improving conditions after 18z to MVFR. KMOT-KBIS MVFR
expected through 10z, improving to VFR after 10z. Winds gusting to
40kts through 08z, then gradually diminishing. KISN-KDIK MVFR
through 04z, then VFR. Winds gusting to 35 kts through 12z, then
diminishing slowly.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until noon CST /11 AM MST/ Saturday for
NDZ003-004-011-012-019>022-034-035-042-045-046.
Wind Chill Advisory from noon CST /11 AM MST/ to 6 PM CST /5 PM
MST/ Saturday for NDZ001>004-009>012-019>022-034-035-046.
Wind Chill Advisory until 11 AM MST Saturday for NDZ031>033-040-
041-043-044.
Wind Chill Advisory until 6 PM CST /5 PM MST/ Saturday for
NDZ017-018.
Wind Chill Warning until noon CST Saturday for NDZ001-002-009-
010.
Blizzard Warning until 6 PM CST Saturday for NDZ005-013-023-025-
036-037-047-048-050-051.
Winter Weather Advisory until 8 PM CST this evening for NDZ023-
025-036-037-047-048-050-051.
&&
$$
UPDATE...AE
SHORT TERM...NH
LONG TERM...NH
AVIATION...WAA
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
709 PM CST Fri Jan 17 2020
.UPDATE...
Issued at 709 PM CST Fri Jan 17 2020
Some rather sizeable adjustments/refinements have been made to
the fcst over the last 3 hrs. Temps have risen to 33-34F at most
cities/towns per airport obs. However...the NE mesonet is still
indicating rural locations were 31-32F. So patchy frzg drzl will
still be psbl until the front arrives.
Simulated reflectivity from hi-res mdls still indicate potential
for 1 to maybe 2 hrs of a light wintry mix (at any single
location) thru 07Z...as the main upr trof moves W-E acrs the CWA.
Hourly POPs have been refined a bit to provide better timing
detail. The HRRR may be overplaying this precip potential. There
really isn`t much on radar...and where returns have moved over
airports...not much has been reported. So precip/QPF amts were
lowered to just 0.01 and that may be generous.
Updated WSW/Advisory statement was sent to decrease precip amts
and remove mention of blowing snow. Any glaze from frzg drzl will
mitigate BLSN potential.
We are watching the Arctic front. It has just entered the Nrn
Panhandle. RAP has been gusting as high as 62 mph. That front will
slam thru the CWA from 04Z-07Z from NW-SE...ending the precip...
with rapid clearing...and rapidly incrsg winds.
Please see LSR for frzg rain amts. The highest amt reported was
3/8 inch just E of HSI. The 3 ASOS ice sensors were less than 1/4
inch.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 322 PM CST Fri Jan 17 2020
A rather complex short term situation is still in store for
tonight with a highly amplified upper trough swinging through
tonight. Isentropic lift is helping to produce drizzle and
freezing drizzle this afternoon and early evening and gives way
to the potential for a light wintry mix later on tonight as a
cold front moves through and kicks up some precip with mechanical
lift. Many areas have warmed just enough to keep most additional
icing at bay. The coating of ice on top of the snow has produced a
hard crust. We could get a bit of a light wintry mix which will
probably transition to a little light snow before ending. The
biggest concern will be wind speeds as 850 mb northwest winds will
howl at 60kt to maybe 70kt behind this cold front, and I would
suspect at least a good chunk of this will make it to the surface
from momentum transfer. I expect at least some spots along and
north of Interstate 80 to get a 60 mph wind gust, and quite
possibly even south of Interstate 80, although not as likely. For
the most part, blowing snow is not a huge concern thanks to the
crust on top of the snow, but if the wind is strong enough and
compromises patches, then this may be more of a problem. Also, any
light snow that may fall late tonight could cause some visibility
problems as well. Kept the Winter Weather Advisory going with the
mixed precip and strong wind, and added the High Wind Warning
along and north of Interstate 80 for strong wind gusts.
As the trough quickly departs, wind speeds will decrease quickly
on Saturday, although we will start out quite breezy. Highs on
Saturday will be cooler and will contrast from lower 20s in our
northeast to near 40 in our southwest.
.LONG TERM...(Saturday night through Friday)
Issued at 322 PM CST Fri Jan 17 2020
A backdoor arctic front will make Sunday quite cold, but we will
be getting only a glancing blow as the 1040+mb surface high moves
from the northern plains and aims toward Iowa, where highs might
not even break zero. Our highs will should at least make it into
the teens northeast to the 20s to near 30 southwest. Gradual
warming ensues with ridging by mid-week, but another wave by
Thursday could give us more snow.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 544 PM CST Fri Jan 17 2020
Significant Wx: IFR gives way to WSHFT/LLWS and G40-50KT.
Tonight: IFR CIGs with vrbl mostly IFR VSBYs in light fog with
DZ at times. A strong cold front will cross the terminals 03Z-04Z
with a WSHFT and improvement to MVFR CIGs. Cold front could be
accompanied by a brief period of mixed wintry precip. Becoming VFR
and windy shortly thereafter. NW winds will rapidly increase 25-35
kt and gust 40-50 kt. LLWS with potential for MOD turbulence at
or below 3K ft. Confidence: High
Sat: VFR with no clds at or below 5K ft. LLWS ends around 15Z. NW
winds gradually subside but will be NW 15-30 kt much of the day.
Confidence: High
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...Winter Weather Advisory until 6 AM CST Saturday for NEZ039>041-
046>049-060>064-072>077-082>087.
High Wind Warning until 6 AM CST Saturday for NEZ039>041-046>049-
060>064-072>074.
KS...NONE.
&&
$$
UPDATE...Kelley
SHORT TERM...Heinlein
LONG TERM...Heinlein
AVIATION...Kelley
Area Forecast Discussion
National Weather Service Green Bay WI
615 PM CST Fri Jan 17 2020
Updated aviation portion for 00Z TAF issuance
and new information added to update section
.UPDATE...
Issued at 558 PM CST Fri Jan 17 2020
The initial snow band with the incoming storm was overspreading
the area from SSW-NNE early this evening. The leading edge of the
snow band was still fighting through some dry air around 850 mb.
But once saturation is achieved and the snow begins, the
visibility drops very quickly. Earlier this afternoon, KOVS went
to 1/4SM +SN within about 1/2 hour of the onset of precipitation.
An impressive mid/upper level dry slot will surge in from the west
during the night and cut off the heavier precipitation, so the
moderate-heavy snow won`t continue all night long.
There is also some agreement among the models for another period
of moderate to perhaps heavy snow in eastern Wisconsin Saturday
morning as QG forcing increases when the main trough axis swings
through. That will coincide with steeper mid-level lapse rates at
the edge dry slot. Also somewhat concerning is the RAP time
section for KGRB showing lift maximized at the same level as -15C
temperatures (favored dendritic growth zone) during that time. The
"crosshair" is rather high above the surface (~13K ft), but still
would be favorable for another burst of snow.
No changes to forecast headlines at this time.
&&
.SHORT TERM...Tonight and Saturday
Issued at 239 PM CST Fri Jan 17 2020
Cloudy skies prevailed across the region this afternoon.
After a cold start to the day, temperatures rebounded into the
upper teens and 20s. Regional radars continued to show a band
of moderate to heavy snow across south-central Minnesota into
east-central Iowa that was moving northeast.
Latest model runs continued to show a prolonged period of snow
across the region tonight into Saturday afternoon, except
lingering Saturday night across the far north. Fairly decent
850mb warm advection noted this evening across the region as the
system approaches the area. The band of moderate to heavy snow
southwest of the area should spread across the region this
evening. Visibilities in this heavy band of snow are expected to
drop to a quarter to a half mile for a few hours as the band
shifts through the area. Snowfall rates of 1 to 2 inches per hour
are possible with this band. Along with the moderate to heavy
snow, gusty southeast winds of 15 to 25 mph are expected, although
may be locally higher near the Bay of Green Bay and Lake
Michigan. There will be a period of very poor driving conditions
this evening due to the low visibilities, high snowfall rates and
blowing and drifting snow.
As the surface low moves into southern Wisconsin late tonight, it
is possible that the precipitation switches over to freezing
drizzle or light freezing rain for a period of time as the bufkit
soundings indicated little ice crystals in the saturated column.
The atmosphere will then become cold enough in the saturated
column Saturday morning to go back to snow across central and
east-central Wisconsin. The surface low is expected move across
eastern Wisconsin and then into Michigan Saturday afternoon.
Snow will continue Saturday morning, tapering or ending for
some Saturday afternoon. Behind the system, gusty west to
northwest winds are expected Saturday afternoon, which will
create areas of blowing and drifting snow.
.LONG TERM...Saturday Night Through Friday
Issued at 239 PM CST Fri Jan 17 2020
Mostly dry and seasonable weather is expected Saturday
night through midweek with northwest upper flow. Lake effect snow
showers in the snowbelt areas could produce a couple inches of snow
Saturday night into Sunday, but the remainder of the region should
be generally dry.
The upper flow is forecast to become southwest Thursday and continue
through the end of the week. Gulf moisture streaming north ahead
of a developing surface low over the Southern Plains could produce
some light snow Wednesday night and Thursday.
There is the possibility of significant winter precipitation
Friday and Friday night, but there are considerable differences
in the track and speed as might be expected.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 558 PM CST Fri Jan 17 2020
Generally poor aviation weather conditions are expected for the
next 24 hours as a large winter storm moves through the region.
Anticipate settling into IFR flight conditions this evening and
then remaining there through tomorrow. LLWS is also expected
tonight (most significant across the NW part of the forecast
area) as SSE winds increase above the surface.
&&
.MARINE...
Issued at 239 PM CST Fri Jan 17 2020
A strong low pressure system will move across the region
late tonight and Saturday, then east of the area Saturday
night. Gusty southeast winds are expected to increase,
with gale force gusts along the Lake Michigan shoreline
through late tonight. There will be a lull in the winds
Saturday morning, possibly lingering into early Saturday
afternoon before gusty west to northwest winds arrive by
mid afternoon. Gale force gusts are likely south of an
Oconto to Algoma line. Winds will be slightly lower to the
north.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 6 PM CST Saturday for WIZ010>013-
019>022-031-038>040-048>050-073-074.
Lakeshore Flood Advisory until 9 AM CST Saturday for WIZ022-040-
050.
Winter Weather Advisory until 6 PM CST Saturday for WIZ018-030-
035>037-045.
Winter Weather Advisory until 6 AM CST Sunday for WIZ005.
&&
$$
UPDATE.........Skowronski
SHORT TERM.....Eckberg
LONG TERM......RDM
AVIATION.......Skowronski
MARINE.........Eckberg
Area Forecast Discussion
National Weather Service North Platte NE
533 PM CST Fri Jan 17 2020
.SHORT TERM...(This evening through Saturday night)
Issued at 303 PM CST Fri Jan 17 2020
A two pronged weather event tonight featuring a Pacific cold front
across WY sweeping through swrn Nebraska and a strong arctic cold
front across MT/SD sweeping through ncntl Nebraska. The models
appear to have backed off on the strength of the Pacific cold front
as wind gusts are expected to reach about 55 mph across the swrn
Nebraska but remain strong near 60 mph across ncntl Nebraska.
The wind gust forecast tonight uses a blend of the NAM, HRRR and RAP
models for gusts to around 60 mph. A few counties have been added to
the High Wind Warning, including Custer county as the models show a
strong corridor of 65-70kt h850mb winds reaching down into scntl
Nebraska.
The model blend mentioned above plus the HREF was the basis for the
snow forecast tonight. The PCPN mode is steep lapse rates and snow
showers but the forecast solution shows 1 to 2 inches of snow to the
lee of the Black Hills across Sheridan county where a convergent
zone will develop. Elsewhere, an inch or less snow is expected. The
strong winds will accompany the snow showers at times and this will
briefly reduce visibility to 1/2 mile or less. The convective
enhancement as indicated in the HRRR echo top product could cause
the showers to tap into strong winds aloft and produce very strong
gusts at the sfc.
The temperature forecast uses the model blend plus bias correction
tonight and Saturday night. No bias correction was used for
Saturday`s highs which are about 3 to 6 degrees cooler than the
straight guidance blend.
.LONG TERM...(Sunday through Friday)
Issued at 303 PM CST Fri Jan 17 2020
1044mb arctic high pressure centered over northwest Canada will
build south and be centered over Sioux Falls SD Monday morning.
This could represent the coldest air of the winter as a
temperature of -58F was recorded across northwest Canada beneath
the high this morning. Wrn and ncntl Nebraska will not be on the
cold side of the high but highs in the single digits and teens are
in place across ncntl Nebraska Sunday and Monday. Highs in the
30s and 40s are in place across swrn Nebraska those days also
suggesting an arctic front will be hung up somewhere across the
cntl High Plains. If history is a lesson, this very cold air will
build a bit farther west into swrn Nebraska. Therefore the
temperature forecast Sunday and Monday may need to be adjusted
downward with later forecasts.
No precipitation is in the forecast until Thursday and Friday next
week. The strong arctic high pressure system moves east and is
centered over the Mid Atlantic region Thursday. The circulation from
the high pressure should draw moisture back north into the central
Plains and an upper level low is progged to move through KS
supporting rain and snow across srn Nebraska. WPC, however, suggests
this upper low will be above a 100 miles farther north and if this
occurs, the chances for rain and snow would be higher across
Nebraska. In fact, WPC has southwest and ncntl Nebraska in a 10-30
percent chance for significant winter precipitation in the 24 hour
period ending Friday morning. This suggests the chance for winter
weather late next week is increasing.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 526 PM CST Fri Jan 17 2020
A cold front will sweep southeast through the area tonight. Strong
gusty northwest winds will develop after the frontal passage.
Otherwise low ceilings will clear with VFR conditions developing.
Prior to this expect areas of MVFR and local IFR with possible
scattered rain and snow showers. Gusty northwest winds on Saturday
will gradually diminish with VFR expected.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
High Wind Warning until 7 AM CST /6 AM MST/ Saturday for
NEZ005>010-023>029-038-094.
Winter Weather Advisory until midnight CST /11 PM MST/ tonight
for NEZ005>010-025>029-036>038-059-070-071.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Taylor
Area Forecast Discussion
National Weather Service Tulsa OK
828 PM CST Fri Jan 17 2020
.DISCUSSION...
Thunder probs were tweaked up to scattered from the I-44 corridor
south and east to near the AR state line. Latest SPC mesoanalysis
indicates rising elevated CAPE, albeit still weak overall, across
eastern OK ahead of a strong shortwave trough. This gives more
confidence in the latest HRRR solutions in developing a band of
showers and storms near I-44 and tracking them east. Other more
isolated activity is expected over SE OK as well. Regardless,
severe potential remains very low due to the weak instability.
Lacy
&&
.PREV DISCUSSION... /Issued 754 PM CST Fri Jan 17 2020/
DISCUSSION...
A progressive shortwave trough with a strong, embedded PV max over
SE CO/SW KS is marching east this evening. The surface reflection
was also shifting east across W KS attm. South winds and warm
advection continue ahead of the surface low and temps are slowly
rising across the region. Per the latest SPC analysis, a corridor
of weak 100-250 J/kg elevated CAPE extends from south central up
into northeast OK. As the strong forcing from the upper system
interacts with this corridor of weak elevated instability, some
storms are possible. The last couple runs of the HRRR are
insistent on developing a few storms in a band roughly along I-44
and then advancing east from there between now and midnight. Given
these trends, thunder mention was expanded to entire precip area
but have decided to keep it isolated given the weak instability.
PoPs were reduced a bit from BVO to TUL and points west behind
this last batch of showers moving thru as coverage/uncertainty of
storm development behind it doesn`t warrant categorical PoPs. Rain
chances will come to an end from west to east, clearing W AR by 3
or 4 AM.
Lacy
PREV DISCUSSION... /Issued 511 PM CST Fri Jan 17 2020/
AVIATION...
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
IFR cigs/MVFR vsbys to prevail as light rain begins decreasing
in areal coverage from west to east in the 05z-07z period. VFR
elements to prevail at all sites by the 14z-16z time period. W-NW
sfc winds behind a passing cold front will ensue later tonight
with gusts of 20-25 becoming common across the area and continuing
for the remainder of the period at all sites.
PREV DISCUSSION... /Issued 333 PM CST Fri Jan 17 2020/
DISCUSSION...
Temperatures have warmed above freezing in all areas this
afternoon and the slow upward trend will continue through the
early part of tonight. Broad warm conveyor belt will continue to
shift east through this evening taking the steady precip along
with it. Continued deep warm advection and moisture transport will
bring enough elevated instability north for at least an isolated
thunderstorm or two tonight. Cold front will eventually move in
late tonight with drier and cooler air, with temperatures falling
in most areas after peaking sometime during the night. Will also
see a period of gusty southwest winds ahead of the front with a
shift to the west-northwest by morning.
Post-frontal airmass is not especially cold and with expected full
sun and even a slight downslope component to the sfc winds, temps
will likely be a bit warmer than NBM guidance. Light winds and dry
air will result in colder temps Saturday night. We will get a
glancing blow of Arctic air arriving in northern areas by Sunday
afternoon and spreading south Monday, with temperatures struggling
to warm much above freezing across far northern areas. Much of
the area likely to see lows in the teens to lower 20s by Tuesday
morning.
Next system still scheduled to impact our weather by mid week.
Warm advection ahead of the system should make this a primarily
rainfall event once again, however this will be contingent on how
fast the shallow Arctic air modifies. Forecast continues to depict
a winter mix in some areas Tuesday night into Wednesday morning
but this does not appear to be an impactful event at this time.
Rain chances will continue with moderating temperatures into
Thursday and early Friday.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 37 49 27 46 / 50 0 0 0
FSM 41 52 28 47 / 100 10 0 0
MLC 40 51 26 48 / 100 0 0 0
BVO 33 48 22 45 / 20 0 0 0
FYV 40 45 25 43 / 100 10 0 0
BYV 40 46 24 41 / 100 10 0 0
MKO 37 50 27 45 / 100 0 0 0
MIO 34 44 23 41 / 80 0 0 0
F10 38 50 27 47 / 90 0 0 0
HHW 46 56 29 49 / 100 0 0 0
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...30