Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/20/21
Area Forecast Discussion
National Weather Service Amarillo TX
554 PM CST Fri Feb 19 2021
.AVIATION...
00z TAF Issuance...VFR conditions are expected for both DHT/GUY.
AMA has a chance for some fog later tonight into tomorrow morning
with MVFR conditions. There is a chance AMA may dip down to
IFR/LIFR with some areas of dense fog for several hours between
06z and 15z. South southwest winds will prevail through the period
at all three sites. Winds will become breezy at DHT/GUY through
the afternoon and evening hours tomorrow with wind speeds around
10 to 15 knots and gusts up to 25 knots possible.
&&
.PREV DISCUSSION... /Issued 140 PM CST Fri Feb 19 2021/
SHORT TERM...Tonight through Tomorrow Night...
Under a cloud free sky and lee side troughing, we are finally
seeing temps rise above freezing this afternoon. Satellite reveals
that there is still quite a bit of area across the Panhandles
under snow cover. The sun will help melt some of this. However,
the southeast TX Panhandle is still expected to still have snow
cover overnight. With light winds and a slight upslope flow, the
southeast is the most likely to have some freezing fog overnight.
Visibility may get below a mile at times. The NAM suggests that
more of the area may see this fog potential, but hi-res models
like the HRRR are not as keen on this. Will need to monitor the
trends this evening closely.
Saturday will see the upper level flow turn zonal ahead of the
next system. The trough is set to come onshore across southern
Oregon/northern California and dive across the desert southwest by
Saturday night. The surface low that forms with this system will
move east across southern KS/OK Panhandle and bring the next cold
front to the area starting early Sunday morning.
Beat
LONG TERM...SUnday through Thursday...
H500 northwesterly flow will start for the long term forecast
period becoming westerly by the middle of next week. From Sunday
through Tuesday, the main H250 jet displaced to the north in the
central Plains along with westerly and southwesterly surface flow,
temperatures will begin to warm up the Panhandles with dry
conditions expected. Highs on Sunday will start below average with
highs in the 40s (lower 40s along the eastern corridor of I-40 in
the TX Panhandle with residual snow cover). Going into Monday and
Tuesday, high temperatures will rise into the mid/upper 50s and
then mid to upper 60s respectively. Tuesday will likely be the
warmest day of the up and coming week ahead of our front dropping
temperatures and our next chance of precipitation.
As the main large scale H500 ridge shifts west for the western
CONUS coast further into the Atlantic, the western CONUS domain
will have an enhanced sinusoidal flow which will help to steer
disturbances into the southwestern CONUS. As a result, latest
19/12Z model and numerical data shows a H500 trough moving ESE
into the Panhandles in the wake of a surface cold front late
Wednesday night into Thursday morning. Going with the latest NBM
guidance, light snow will be possible for the northwestern
Panhandles but could extend further southeast if system moves
slower and the positive tilted trough moves further southeast.
Latest GFS shows a progressive trough moving southeast and out of
the area by Thursday evening. NBM/ECMWF shows the main H500 trough
enhancing surface cyclogenesis in south Texas near a stalled
frontal boundary which could bring an additional round of
precipitation for the eastern Panhandles on the western periphery
of the second surge of moisture transport. Precipitation type at
the beginning and the end may be a rain/snow mix but most of the
event should be in the form of snow as temperatures behind the
passing cold front Wednesday night will be below freezing for all
locations in the Panhandles. too early at this time to determine
QPF amounts but check back for updates. Not the most favorable
temperatures outlook given our record breaking col temperatures
this week but high temperatures will drop into the mid 40s to
lower 50s by Wednesday and mid 30s to lower 40s by Thursday.
Meccariello
&&
.AMA Watches/Warnings/Advisories...
TX...None.
OK...None.
&&
$$
23/11
Area Forecast Discussion
National Weather Service Bismarck ND
949 PM CST Fri Feb 19 2021
.UPDATE...
Issued at 940 PM CST Fri Feb 19 2021
For the late evening update we eliminated any pops after 06 UTC.
We have yet to see anything other than some mid-level clouds as
the warm front moved through western ND and now is traversing
central ND. Could maybe see a flurry or two along the Highway 83
corridor through midnight. For lows tonight, we dropped
temperatures in the east and raised temperatures in the west by a
few degrees. Currently Zero at Rolla, and they could drop a couple
more degrees before slowly rising through the rest of the night.
Temperatures in the west behind the warm fron have been slow to
fall this evening. It`s still in the mid 20s out west, but with a
few hours of clear skies (more clouds move in late) and a dry
atmosphere, hate to raise them too much. Updated text products
will be sent shortly.
UPDATE Issued at 534 PM CST Fri Feb 19 2021
A warm front is currently pushing into western North Dakota.
Latest satellite and radar analysis, with observational data and
webcams depict mainly mid level clouds from around 7-10kft with no
precipitation notes as of yet. Comparing latest guidance with
previous forecast, we decided to slow down the progression of
small pops across western into central ND, and for now kept them
as slight chance. Time lagged HRRR seemed to have a good handle
on latest cloud cover so used this as the bulk of guidance for
clouds tonight. Forecast soundings do show a little shallow low
level moisture late tonight into Saturday, but not really
confident about low clouds at this time.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 231 PM CST Fri Feb 19 2021
A chance of light snow is in the forecast tonight with warmer
temperatures on Saturday.
A north-south oriented warm front was across eastern Montana and
approaching the western North Dakota border this afternoon. This
front is expected to push across the state tonight with the
arrival of a weak mid- level shortwave trough. Increasing clouds
and a chance of light snow (with possibly rain mixed in initially)
will accompany this front. Upstream observations in Montana
indicate only light precipitation so far with liquid totals of a
trace to several hundredths of an inch. The ceiling for
precipitation should be similar in west/central North Dakota,
especially with an antecedent mid-level dry layer to work through.
12Z HREF was leaned on for precip timing as well as longevity, as
the CAMs that do carry snow through the forecast area wane
intensity in the eastern portions of the state.
Saturday, a broad trough begins to dig through the Four Corners
region, with mostly zonal flow across the Northern Plains. A 700mb
wave crosses South Dakota through Kansas, but should stay far
enough south to keep precipitation out of the state through
Saturday night. 12Z guidance is somewhat inconsistent in the
deepening of this wave early Sunday morning, with a few solutions
wrapping QPF into the southern James River Valley of North Dakota.
A slight chance of snow was introduced but notable accumulations
are not expected at this time.
.LONG TERM...(Sunday through Friday)
Issued at 231 PM CST Fri Feb 19 2021
Gradually warmer temperatures are expected through the early
portion of next week. The warmest temperatures are expected to be
Monday as well as potentially windy conditions.
Broad ridging in the upper levels begins to take over Sunday into
early next week with warmer temperatures expected, especially
Monday. Strong unidirectional flow in the upper through lower
levels is also expected as an upper level jet noses into the
region. The overlap of 40-50kt 850mb winds and deeper boundary
layer mixing looks to be west and south central, well signaled by
GFS/EC ensemble wind gust potential. Thus we will introduce the
potential for a Wind Advisory in the HWO for these areas. Given
adequate mixing, there is a strong chance for highs to reach 50
generally near and west of the Missouri River with 40s elsewhere.
If cloud cover behaves, NBM and MEX/ECM are in good agreement of
the high end potential of upper 50s in these historically warmer
locations.
The latter half of next week will be characterized by a cool down,
though with still near or above average temperatures. 12Z
guidance is consistent in running weak, embedded waves through the
region with any precipitation being light. Thus the blended
guidance produces a mostly dry forecast for now. There is some
agreement of a chance of snow or rain on Tuesday as the next front
pushes through.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 940 PM CST Fri Feb 19 2021
VFR conditions expected through much, if not all, of the 06Z TAF
period. A weak warm front and associated cloud cover is currently
working its way into the central portion of the state and will
continue moving east this evening and overnight. There is a slight
chance this cloud cover may produce MVFR ceilings along with some
flurries at times across the south, but confidence is not high
enough to include MVFR ceilings or VCSH in the TAFS at this time
due to an abundance of dry air above the surface.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...TWH
SHORT TERM...AE
LONG TERM...AE
AVIATION...TWH
Area Forecast Discussion
National Weather Service Dodge City KS
521 PM CST Fri Feb 19 2021
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Saturday)
Issued at 255 PM CST Fri Feb 19 2021
What a difference a couple of days make! Temperatures have actually
over-achieved a bit across southwest Kansas, thanks to the ever-
growing hole in the snowpack centered right over our forecast area.
The temperature peaked at 45 degrees officially here at Dodge City,
which is a wonderful rebound from the morning low of 9. The warming
trend will carry right into tomorrow with warmer than previously
forecast highs...well into the lower 50s for most. The next storm
system will be approaching late tomorrow and tomorrow night, and as
it does so, stratus clouds will build back in, and low level warm
advection will increase east of the developing low. The increased
low level warm/moist advection will most likely manifest as a
growing area of freezing drizzle late in the night after
temperatures drop back down into the lower 30s or even upper 20s.
This could cause some problems for those that may be out and about
late Saturday Night, particularly for areas north and east of Dodge
City. This is something we will have to continue to monitor closely.
The heavier, accumulating precipitation with this storm system is
still expected to be well east-northeast of our forecast area.
.LONG TERM...(Saturday night through Friday)
Issued at 255 PM CST Fri Feb 19 2021
Behind the weekend storm system on Sunday, winds will pick up out of
the north at 20 to 35 mph. Strongest of the winds are expected to be
during the first half of the day when the pressure rises behind the
front are greatest. The cold advection will be masked by downslope
warming some, so the drop in temperatures Sunday will not be all
that great over what we will see Saturday afternoon. Thereafter,
Monday and especially Tuesday still appears to be very mild with
highs around 60 Monday with mid to perhaps even upper 60s now
possible Tuesday afternoon. This warmth will only last two days,
though, as another frontal system impacts the Central Plains
region mid-week, potentially marking the beginning of a more
unsettled pattern with the mean upper level trough axis out west
of us.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 504 PM CST Fri Feb 19 2021
Southerly winds will become more southwesterly after midnight with
a period of light and variable winds being possible around
daybreak. Latest HRRR BUFR soundings appears to have backed off
on the near surface moisture return given the gradually veering of
the surface winds. Still with light and variable winds around
daybreak the potential still exists for some patchy freezing fog
being possible with visibilities falling as low as one mile at
times between 10z and 14z Saturday. The light winds early Saturday
morning will back to the southeast and increase to around 20
knots after 18z Saturday as surface pressures begin to fall across
eastern Colorado.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 20 53 27 47 / 0 0 10 0
GCK 17 52 25 45 / 0 0 0 0
EHA 20 53 27 45 / 0 0 0 0
LBL 16 51 25 47 / 0 0 0 0
HYS 17 52 24 45 / 0 0 30 0
P28 16 41 27 48 / 0 0 20 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...Burgert
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
713 PM CST Fri Feb 19 2021
...Aviation Update...
.DISCUSSION...(This evening through Friday)
Issued at 230 PM CST Fri Feb 19 2021
Variably cloudy skies are being observed across the region this
afternoon and are expected to continue into the evening and
overnight hours. So far...this cloud cover has had minimal impact
on temperatures...which are struggling to get out of the mid-20s
in snow covered area...while they have warmed into the mid 30s
across our KS counties...which have comparatively little snow
cover remaining.
With some melting of snow today due to the breaks in the cloud
cover and increasing sun angle...available moisture in the low
levels should be sufficient for the formation of fog this evening
and overnight. SREF probs are pretty high in confidence for fog
formation...and the last few runs of the HRRR are giving us dense
fog overnight...so upped the areal coverage of fog in the
forecast along with introduced some lower visibilities into the
actual wording of the forecast. That said...if trends
continue...would not be surprised if a dense fog advisory
eventually becomes necessary late this evening or overnight for
more widespread visibilities near or below 1/4 SM.
Depending on if/when/how quickly the fog burns off on
Saturday...temperatures might be a bit too optimistic...but either
way there will likely be a significant temperature gradient from
the snow free areas across north central Kansas to snow covered
areas just a bit further north. Tomorrow night...expect the next
upper level disturbance moving out of the Rockies to spread some
light precip across the local area...likely beginning as freezing
drizzle near and southeast of the Tri-cities before transitioning
to all snow by Sunday morning. With a good signature for freezing
drizzle in both soundings and in precip fields from the NAM...the
likelihood of some light icing is looking pretty good by Sunday
morning...although overall accumulations of ice should be in the
few hundredths of an inch of precipitation range. Thereafter...
some very light snow accumulation is possible mainly through the
first half of Monday...but the main impact of this system does not
appear to the be the snow itself...rather the tightening pressure
gradient associated with the deepening surface low...which could
result in wind gusts near 40 mph during the daytime hours on
Sunday. While this will not be one of the strongest wind producers
we have seen this winter...winds will likely be strong enough to
pick up some of the un-crusted snowpack we have across the
region...resulting in possibly some blowing and drifting snow
(from previous storms) Sunday. While blowing snow does not have a
mention in the official forecast just yet...decided to add some
wording for its potential to the HWO this afternoon.
Thereafter...dry weather should prevail as the upper level flow
turns more westerly and milder weather returns to the local
area...at least to start the week...before a dry cold front
arrives mid-week dropping temperatures back down below climo.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 713 PM CST Fri Feb 19 2021
General overview:
Although confidence is fairly high that the first 3-6 hours and
final 3-6 hours of the period will feature prevailing VFR
conditions, the middle 12-18 hours centered on late tonight-
Saturday morning brings a decent chance of sub-VFR visibility (and
probably ceiling as well), as at least light fog is good bet, and
dense fog a possibility but not overly-high confidence at this
time. As for winds, no big issues here, as speeds throughout the
period will only average 5-10KT at most, with direction overnight
into Saturday morning fairly variable, and a more consistent
southeast direction established by later Saturday afternoon.
Additional ceiling/visibility details:
As mentioned, confidence in just how "bad" fog and resultant
visibility/low ceiling overnight into Saturday morning is not the
greatest, especially given that some models/guidance tend to be
over-aggressive with the severity of overnight fog development
prior to the occurrence of more widespread above-freezing daytime
temperatures/significant snow-melt (neither of which occurred at
KGRI/KEAR today). As a compromise between the most
optimistic/pessimistic fog solutions (but leaning toward the
pessimistic), have opted to go as low as IFR/LIFR during mainly
the 09-17Z time frame, but did not have the confidence to go full-
blown VLIFR in long-lasting dense fog. No matter how bad fog gets
during the period, confidence is at least medium-high in a return
to VFR visibility by around 17Z as fog lifts/dissipates.
The bottom line: Stay tuned for potentially notable changes
regarding expected visibility/ceiling in later TAFs/amendments.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Rossi
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Goodland KS
355 PM MST Fri Feb 19 2021
.SHORT TERM...(This evening through Monday)
Issued at 230 PM MST Fri Feb 19 2021
Patchy freezing fog will be a concern once again tonight along the
Republican River valley in southwest Nebraska and into Decatur,
Norton, Graham and Sheridan counties in northwest Kansas. These
areas did not warm up much today and dew point depressions remain
relatively low. HRRR suggesting fog may be dense at times.
Elsewhere, light westerly winds and larger dew point depressions
should keep fog from developing, though cannot completely rule it
out in low lying areas. Low temperatures will be in the teens,
possibly single digits in low lying areas such as the Republican.
Moderating temperature trend will continue on Saturday as upper
ridge axis moves across the area combined with breezy south winds
at the surface. Expecting highs generally in the upper 40s, a bit
cooler around McCook which may only reach the lower 40s. Next
system will move into the central Rockies Saturday afternoon and
across the area Saturday night. Expecting light snow north of
Interstate 70, less than one inch, with perhaps mixed
precipitation after midnight in eastern areas where moisture/cold
air will be shallow. Best chance of accumulating ice, a hundredth
or two, will be from McCook to Hoxie and Hill City. In addition to
the precipitation, breezy to windy northwest winds will accompany
the associated surface cold front. Strongest winds will be in
western areas near the Colorado border after midnight, with gusts
up to 40 mph possible.
The system will quickly exit the area early Sunday morning with
skies becoming mostly sunny by the afternoon. Breezy to windy
northwest winds will continue, gradually diminishing by the
afternoon. High temperatures will be in the upper 30s to lower 40s
and lows Sunday night in the teens and 20s.
Upper ridge will begin to build over the region on Monday
resulting in sunny skies and much milder temperatures.
We are expecting highs in the 50s across the entire area with
breezy west winds. Lows Monday night will be in the 20s.
.LONG TERM...(Tuesday through Friday)
Issued at 102 PM MST Fri Feb 19 2021
The main points of interest for the extended period include warmer
weather for the start of the forecast period with a chance of
precipitation towards the middle of the work week.
Tuesday into Wednesday, northwesterly flow will back into more
westerly flow in advance of an approaching trough. Some
disagreements in timing of the trough exists within guidance as
the GFS is the faster solution. A cold front is forecasted to
enter Yuma County during the late afternoon on Tuesday, the GFS
also has some precipitation forming late Tuesday night, whereas
the ECMWF is roughly 12 hours later with with the precipitation
chances. Currently the best area for precipitation to occur is
along and west of the Kansas/Colorado border, with the possibility
of flurries along and east of Highway 25 on Wednesday. Highs on
Tuesday are currently forecast to be in the upper 50s to low 60
across the entire Tri-State area. The timing of the cold front
will need to be watched as if it moves through earlier then our
forecasted temperatures might be to high. Highs for Wednesday will
be noticeably cooler in the 30s to 40s and overnight lows falling
into the teens to 20s.
For Wednesday night through the remainder of the forecast period,
guidance does not agree well as mentioned before as the GFS is
faster with the passage of the trough. The GFS ensembles brings in
weak ridging during the day Thursday. The ECMWF and Canadian model
hints at the potential for some snow showers on Thursday night, but
my confidence at this point is not high enough to introduce into the
forecast. High temperatures on Thursday will be similar to Wednesday
with upper 30s to low 40s expected, before a slight warm up for
Friday as highs reach the 40s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 353 PM MST Fri Feb 19 2021
At KMCK...freezing fog expected to develop once again in the
Republican River valley tonight, including near KMCK. Visibility
may drop to IFR towards early Saturday morning before improving by
mid Saturday morning to VFR.
At KGLD...VFR expected to prevail through the TAF period. Surface
winds will increase from the south by Saturday afternoon, with
gusts to 25kts possible.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...024
LONG TERM...TT
AVIATION...024
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
907 PM EST Fri Feb 19 2021
.SYNOPSIS...
Low pressure passing south of New England will bring light snow
through late tonight. An upper trough swinging through Saturday
will bring scattered snow showers to the mountains. High
pressure builds in Sunday followed by a quick hitting system
Monday and Monday night. A weak system will cross south of the
region Wednesday night and early Thursday. Temperatures will be
on the rise through the middle of the week with above normal
temperatures expected for much of next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update...Heaviest band of snow is beginning to slide E of the
forecast area. Snowfall intensity is coming down now...as
evidenced by rapidly improving visibility across the region.
Scattered snow showers are already popping up in the axis of the
upper trof...and I expect this activity to continue most of the
night despite steady precip moving out to sea.
Previous discussion...
Impacts...Light snowfall continues
through this evening, gradually coming to an end late this
evening. There is a chance for higher snowfall rates and totals
over the I-95 corridor in York County and the Seacoast of NH,
and while this would pose some threat for accumulating snow on
roadways and reductions in visibility, this would occur
primarily after the evening commute.
Weak low pressure continues to pass well to the southeast of Cape
Cod today as light snow continues over all but the northernmost
zones of the CWA. The trend throughout the day has been for
visibility to fluctuate with the intensity of the snow, but all
of the automated sites have stayed above 3/4 to 1 mile and
amounts have generally been rather light so far. However, this
afternoon through this evening does look like a period where we
may see some significant accumulation before things wind down
later this evening, at least for some locations.
High-res guidance continues to indicate some enhancement in rates
and totals for the I-95 corridor from Portland south through the
Seacoast of NH, though the mechanism for getting there appears to
differ. The HRRR shows what appears to be a mesoscale/ocean effect
band moving onshore after 00Z that provides a quick burst of an inch
or so for those areas...while the NAM shows a more broad enhancement
through much of southern NH with similar amounts but from now
through this evening. Decided to incorporate both of these scenarios
into the QPF and snow amounts, and some locations along the coast
between Portland the Mass. border could get around 3 inches total
while amounts elsewhere in southern NH and York County should be
closer to 1-2 inches. Certainly some bust potential, particularly
with that HRRR scenario...but thought it best to include it now to
be removed later if it never materializes since the evening commute
could be affected. Area webcams indicate that major highways look to
be in good shape at the moment, but heavier snowfall rates could
lead to issues for the evening commute, particularly with
cooling pavement temperatures; if conditions warrant, could
issue an SPS to cover this.
Most locations outside of those discussed above are looking at
another half inch before things finally wind down later this
evening. Light snow will continue through the overnight hours before
finally coming to an end early Saturday morning with most locations
picking up another tenth or two.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Impacts...Minimal. Snow showers will be possible in the mountains on
Saturday.
As low pressure pulls away on Saturday, northwest flow develops in
its wake. A mid-upper trough also swings through the region, and
between it and the northwesterly upslope component, expecting at
least a few snow showers in the mountains with very light
accumulations. Clouds will linger, keeping skies mostly cloudy, and
the northwest winds will be steady throughout the day. High
temperatures will rise into the mid to upper 30s in the mountains
and the lower to mid 30s elsewhere. High pressure begins to build
into New England Saturday night, putting an end to any lingering
snow showers in the mountains and allowing skies to clear for
most of the CWA. Blended in some of the cooler guidance for lows
Saturday night, yielding lows ranging from the positive single
digits north to the mid to upper teens south.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
High pressure will build towards New England from the west on
Sunday. It will be mainly clear with temperatures slightly below
normal for this time of the year in the mid 20s north to the
lower 30s in the south. Downslope northwesterly winds will aid
the drying and sunshine over southern locations.
The narrow ridge of high pressure will crest over the forecast
area during the evening hours. With light winds and clear skies,
temperatures will quickly fall after sunset due to radiational
cooling. Temperatures may level off late at night with clouds
increasing after midnight. Nevertheless, temperatures will
easily fall into the single numbers in the north to the lower
teens across portions of the coastline. Have forecasted min
temperatures slightly below most model guidance. This cold air
will likely play a role in the ptype across interior locations
as we start out a new work week.
The 12Z operational and ensemble solutions continue to have
subtle but important differences in the development and track of
low pressure late in the day Monday and Monday night. The Euro
and Canadian indicate the development of the surface low
slightly further offshore than other model solutions. The Euro ensemble
mean tracks the surface feature through the Gulf of Maine Monday
night. This track, or a track near a coastal front seems
reasonable given the cold place likely to be in place in Maine
and New Hampshire.
Despite the cold air in place enough warm air both at the
surface and aloft may make it into coastal areas to allow for a
changeover to rain after a period of snow. This changeover has
been supported by the Euro ensemble mean low level temperatures
as well as NBM ptype probabilities. There is also the
possibility of a narrow ribbon of freezing rain during this
event. However, confidence levels remain low for this
possibility and any changeover would be brief.
The system will be a quick mover so snow amounts should not be
overly high as QPF remains moderate at best.
A gusty westerly flow develops thereafter through the midweek
period. Despite some initial cold air advection on Tuesday,
temperatures will be above normal for much of the week.
Temperatures in the 40s are possible Tuesday through Thursday.
During this period, a weak system may pass south of our region
Wednesday night or early Thursday. Early indications continue to
indicate a weak and fast moving system.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Light snow continues through late this evening or
early tonight for most terminals. HIE is the only site not
currently snowing, but it looks like some is on the way.
WIdespread IFR conditions will gradually improve to MVFR and
perhaps VFR by Saturday morning. Northwest winds increase
Saturday morning.
Long Term...VFR expected Saturday night through Monday morning.
MVFR to IFR conditions expected in snow and rain Monday
afternoon and evening. Improvement to VFR possible late Mon
night.
&&
.MARINE...
Short Term...SCA remains in effect for the outer waters as winds
and seas finally begin to reach criteria this afternoon. Light
snow over the waters should be winding down this evening into
tonight, followed by increasing northwest winds Saturday morning
and afternoon. Those northwest winds could lead to some light
freezing spray Saturday night.
Long Term...A northwesterly gradient will continue to support gusty
winds on Sunday. Winds will pick up out of the southwest on
Monday into Monday evening ahead of a fast moving system
bringing building seas to the region which will continue on
Tuesday into Wednesday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 7 PM EST Saturday for ANZ150-152-
154.
&&
$$
NEAR TERM...Legro
Area Forecast Discussion
National Weather Service Lincoln IL
902 PM CST Fri Feb 19 2021
.SYNOPSIS...
Issued at 328 PM CST Fri Feb 19 2021
Clouds will increase into this evening, as scattered snow showers
develop across areas north of a line from Rushville to Danville.
However, any snow accumulations that do develop will remain around
a dusting to less than a half inch. Lows tonight will remain cold,
in the single digits above zero. Patchy fog could develop into
Saturday morning, with partly cloudy skies and warmer temperatures
Saturday afternoon.
&&
.UPDATE...
Issued at 902 PM CST Fri Feb 19 2021
A warm front just south of the forecast area and warm advection
above the surface is resulting in a few very light precipitation
reports north of I-74, and models suggest this zone should
gradually shift eastward through the night. Only low chance
values for measurable precipitation are in the forecast along and
north of I-74, and this looks good. Otherwise, have added some
additional cloud cover late this evening in west central IL based
on satellite trends, and added a few degrees to low temperatures
due to cloud cover and recent observations above forecast.
Exception is southeast IL, where little change was made from
single digit forecast lows.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 328 PM CST Fri Feb 19 2021
An upper level shortwave evident on satellite loops in west-
central Illinois will progress across the northern portions of
our forecast areas tonight. Clouds will increase as forcing for
precipitation increases under positive DPVA. Periods of light snow
or flurries are expected, but confidence in the amount of
measurable snow is still low. Upstream obs have been void of snow
under the radar returns. The 18z NAM3K still indicates a narrow
swath of 0.5" snow north of Peoria to Bloomington, while the
latest HRRR barely indicates small areas of 0.1". Due to marginal
confidence, have kept PoPs in the 20-40 pct range this evening
into the overnight.
Southerly winds overnight combined with some cloud cover will
help prevent the bitterly cold sunrise temps of this morning.
However, we will still remain well below normal, with lows in the
single digits above zero and wind chills in the single digits
below zero.
Saturday may start out with patchy fog or freezing fog again, due
to sunrise producing some light melting on Friday. Impacts from
that should remain low. The rest of the day will see decreasing
clouds from south to north, helping to push high temps toward the
freezing mark for areas south of Springfield to Effingham.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 328 PM CST Fri Feb 19 2021
While the extended forecast will be dominated by the warming
trend, we still have one wintry precip event to close out the
weekend. Sunday morning will feature the development of a warm
frontal circulation across our CWA, as low pressure advances from
near Colorado Saturday evening toward Illinois on Sunday. The low
track is still projected to be across the northern portions of
Illinois, with the warm frontal boundary located roughly along or
north of I-74 as the low reaches Illinois. Boundary layer should
occur by afternoon, with snow the primary precip type initially
for areas north of I-72, and a mix of rain and snow south of
there. A steady surge of warm air during the day will transition
the precip type toward rain as far north as I-74. However, plenty
of snow on the ground will delay the surface temp warm-up above
freezing on Sunday. That could set the stage for the rain drops to
reach the ground while surface temps remain at or below freezing
in some areas. As a result, a period of freezing rain can not be
ruled out. However, there should not be significant icing from
freezing rain due to eventual warming above freezing in our entire
CWA Sunday afternoon.
Snow amounts remain a tough call, but if the snow lingers longer
north of I-74 Sunday afternoon, we could see snow accum climb up
to 1-2", mainly from Galesburg to Lacon to El Paso. At this point,
we have a half inch of snow as far south as Peoria to Bloomington
to Champaign, but that snow could get rained on as the warm front
briefly surges northward later Sunday afternoon. Once the low
passes across northern IL, somewhat colder and dryer air will
filter into Illinois. Any lingering precip after midnight Sunday
night could change back to snow before ending, but current
thoughts are precip will end before a deep enough layer of cold
air advances into eastern IL.
Beyond that system, the pronounced warming will develop, under the
zonal flow aloft. Pacific origin air will advance into IL, helping
to push high temps into the 40s across the board on Tuesday and
Wednesday. The remaining snowpack will keep Monday`s highs a bit
colder than guidance, but very little snow is expected to be
remaining for the Wednesday warm-up.
A weak cold frontal passage Wed night will trim 6-8 degrees off of
high temps for Thursday and Friday, as Pacific Northwest high
pressure shifts east across the Plains into Illinois. Highs will
generally settle out in the mid 30s north of Peoria to the low
40s south of I-70.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 547 PM CST Fri Feb 19 2021
Areas of MVFR cigs and light snow expected to develop this evening
for mainly around KPIA-KBMI-KCMI. Snow expected to end by 08Z-
10Z. Cigs expected to lift and dissipate somewhat by 17Z, becoming
VFR, however some re- development of cloud cover could develop in
the afternoon, resulting in occasional MVFR cigs. Winds W 5-10 kts
becoming light and variable overnight. SE winds 5-10 kts expected
to develop by 17Z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...37
SYNOPSIS...Shimon
SHORT TERM...Shimon
LONG TERM...Shimon
AVIATION...37
Area Forecast Discussion
National Weather Service Memphis TN
923 PM CST Fri Feb 19 2021
.UPDATE...
Temperatures are beginning to plummet across the area due to
mostly clear skies, calm winds, and lingering snow pack on the
ground. Will update to make some adjustments to temperatures. The
other thing that we will continue to watch is for the possible
development of freezing fog. The HRRR has been showing development
of fog across the Mississippi Delta on every run for the last 24
hours. If that occurs it may keep lows from dropping as much
depending on how dense the fog gets.
KRM
&&
.DISCUSSION... /issued 242 PM CST Fri Feb 19 2021/
Skies remain sunny across the Mid-South this afternoon with
temperatures ranging from the mid 20s to upper 30s. High pressure
extends from the Texas northeastward into the Mid-South at this
time.
The surface high will slide slowly east tonight. With snow
remaining on the ground temperatures will be quite cold tonight
with lows Saturday morning mainly between 10 and 15 degrees. A
couple of locations may see wind chill values approach 0 but most
areas will be readings in the single digits. Some freezing fog may
also develop late tonight and could become widespread overnight.
Saturday will be sunny as the surface high starts to move east of
the Mid-South. Winds will shift to the south on Saturday allowing
for milder air to move into the region. Temperatures will be
warmer with highs in the lower 30s to mid 40s. Dry weather will
continue into Saturday night as milder air continues to move into
the region. Temperatures will milder Saturday night with lows
Sunday morning in the low to mid 20s. Some freezing fog may
develop again Saturday night.
On Sunday, a cold front will move across the southern plains and
into Arkansas. Scattered showers are expected to develop ahead of
the front and some of the activity may move into northwest
sections of the Mid-South in the afternoon. Temperatures will be
warmer with highs in the lower 40s to mid 50s.
The cold front will move through the region Sunday night with more
rain expected to move through the Mid-South. As the front moves
east of the region on Monday, precipitation will be ending in the
morning with a mix of wintry precipitation possible before moving
out.
High pressure will move back into the region by Monday night
bringing a period of dry weather for Monday night through
Wednesday. Temperatures will be cooler Monday but warm back up for
Tuesday and Wednesday.
Another cold front will move through the region for Wednesday
night and Thursday bringing more rain to the Mid-South. This front
will stall out across southern Mississippi so more precipitation,
some of it possibly wintry, is expected for Thursday night and
next Friday.
ARS
&&
.AVIATION...
VFR conds will continue into the evening. The main forecast
concern is whether freezing fog will develop as advertised by the
HRRR/HREF. There has been some melting and as result some
additional moisture lying around. However this will quickly
refreeze as temps fall. Seems like the excess moisture in the
boundary layer will deposit on the ground and surfaces as frost vs
forming freezing fog. Also the HRRR has some odd surface temp
data by 06z with temps falling below zero across parts of the
Delta which is highly unlikely. This is the area where the
freezing fog is first predicted to develop by the HRRR. Attm will
hedge with a 3SM BR tempo 1SM BR at KMEM, KJBR and KMKL. Forecast
confidence is low from 20/06z - 20/15z.
Winds will be light overnight becoming light south on Saturday.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$