Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/28/19
See below for an aviation forecast discussion for the 00Z TAFs.
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 233 PM CST Wed Feb 27 2019
Some more light snow expected in the very short range, along with a
bit of a warm-up. Surface high pressure will continue to keep the
northeast cwa cold and dry overnight. Meanwhile, a fairly weak pv
anomaly tracks across the Rockies and into the plains overnight and
into Thursday morning. It appears the best UVM with this feature
will slide along the southern border of the cwa. The overall trend
of the last few model runs has been to track the system a little
further south. QPF/Snow amounts look fairly low, probably and inch
or less snow accumulation. As the sfc high slides off to the
southeast, a slightly warmer airmass will infiltrate the region,
with temperatures both Thursday and Friday topping out in the teens
east, and 20s west.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 233 PM CST Wed Feb 27 2019
Will initially start out with zonal, west to east flow aloft with a
large area of low pressure over the Canadian prairies, and a trough
extending off the coast of WA. This will quickly change as a
shortwave/trough rotates around the southern end of the Canadian
low, and moisture surges across the Northern Plains. At the surface,
the elongated low over WY/CO will push a trough southwest to
northeast across SD by 12Z Friday, before quickly weakening to our
southeast during the day. On the southern and back edge of the
precipitation, we could end up with a potential mix. At this point,
will keep any mixed precip over mainly Jones/Lyman Counties between
09-17Z Friday. Storm total snow of 1 to near 4in will be possible,
with plenty of room for change between now and then as this system
has initially shown signs of being a little weaker. Best chance of 1
to 2in overnight into the morning commute will be over the eastern
2/3 of the forecast area, and then another 1 to 2in of snow over the
northeastern half of the forecast area during the daytime hours
Friday morning.
The pesky 500mb low will finally exit over Lake Huron and Ontario on
Sunday, with a broad trough extending over our area slowly losing
hold through Tuesday night. The main impact will be continued cold
air. Highs will be mostly in the single digits either side of zero
Saturday through Monday. With all this cold air in place Wind Chill
headlines are likely to return starting Saturday night, off and on
into Monday morning. Despite the dry conditions, blowing/drifting
snow may still be a concern Sunday through Tuesday. The strongest
winds of 15 to 20kts are expected over north central SD Monday
afternoon and evening. As the time nears, we will likely see an
expansion in the blowing snow and higher winds over the Sisseton
Hills areas too.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
Issued at 540 PM CST Wed Feb 27 2019
VFR skies/vsbys are expected through tomorrow. However, KPIR may
see vsbys drop to MVFR range with light snow for a few hours late
tonight.
Another winter system is in the offing for tomorrow night into
Friday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Dorn
SHORT TERM...TDK
LONG TERM...KF
AVIATION...Dorn
Area Forecast Discussion
National Weather Service Gaylord MI
839 PM EST Wed Feb 27 2019
.UPDATE...
Issued at 839 PM EST Wed Feb 27 2019
A few items of note this evening. A prominent mesolow has formed
along the inverted trof extending into far northern Lake Huron.
This is cycling reasonably healthy snow showers into the Hammond
Bay area of Presque Isle Co. The mesolow has been drifting sw-ward
over the past hour or two. However, light westerly low-level flow
will slowly become established as low pressure exits the mid-
Atlantic states. The remnant mesolow should tend to drift se and
then e over the next several hours, while weakening during any
period that it is over land as opposed to the lake. Have kicked
nighttime snow accums near Huron Beach into the 2-3 inch range for
now.
On the flip side, the opportunity for nnw-flow lake effect to get
well-established into nw lower MI is shrinking. Though we do have
a nnw fetch over on Lake MI presently, winds will be backing
steadily for the rest of night. I do still expect snow showers to
make a return to nw lower MI closer to midnight (per recent HRRR
runs), but have reduced snow accums tonight, especially in the TVC
area.
Finally, in between, clearing skies have allowed temps to tumble
in far eastern upper MI, and in n central lower MI. Grayling has
already been as cold as 0f, and PLN/Cheboygan are 2f presently.
Have drastically reduced min temps in these areas.
&&
.NEAR TERM...(Through Tonight)
Issued at 333 PM EST Wed Feb 27 2019
...Lighter Snows Linger...
High Impact Weather Potential: None for now.
Pattern Synopsis/Forecast: Low amplitude short-wave continues to
advance through the northern Great Lakes region this afternoon
along with a diminishing upper jet core sliding across northern-
central lower Michigan. Surface low pressure has migrated to near
Cleveland with inverted surface trough stretching up through northern
lower Michigan.
Large scale synoptic forcing/snowfall has diminished along with
thinning synoptic scale cloud cover across northern Michigan. But,
with heating, quite a bit of cloud cover has filled back in
across northern lower Michigan. And, along with weak winds/inland
convergence...we still have lingering snow showers/flurries
contracting inland across northern lower Michigan. Lastly, there
are some lake snow showers on Lakes Michigan and Huron also trying
to make inroads into various parts of the CWA.
Tonight: Inverted surface trough axis will continue to slide off
to the east tonight, replaced with high pressure building in from
the plains. We will lose the heating of the day/inland convergence
forced snow showers fairly early on as low level mean flow
becomes more established from the NW. But there will be some minor
lake snow showers to contend with particularly through the
evening hours while lake effect snow parameters remain at there
"best." Anticipate only minor accumulations...couple inches at
best where snow showers are most persistent.
&&
.SHORT TERM...(Thursday through Saturday)
Issued at 333 PM EST Wed Feb 27 2019
...Fairly quiet weather then some more light snow...
High Impact Weather Potential...Low.
Primary Forecast Concerns...Snow accumulations Friday night and
Saturday.
Short wave ridging slowly builds in Thursday and holds into much of
Friday. Subtle warm advection through much of that time will result
in increasingly hostile conditions for lake effect snow development.
Perhaps just a few light snow showers or flurries near the Lake
Michigan shoreline Thursday. Attention then turns to another short
wave which is expected to bring widespread light snow to the region
late Friday through Saturday morning. A general 1 to 3 inches of
accumulation expected with this system (lowest across southeast
counties). High temperatures will moderate from the lower and mid
20s Wednesday to the mid 20s to lower 30s Friday and Saturday. Lows
generally in the single digits above zero Thursday night and the
teens Friday night.
.LONG TERM...(Saturday night through Wednesday)
Issued at 333 PM EST Wed Feb 27 2019
...Turning much colder with lake effect snow showers...
High Impact Weather Potential: Low.
Perhaps a few light lake effect snow showers Saturday night. The
bigger story will be another surge of arctic air which will dive
into the region Sunday and hang around into the middle of next week.
This will lead to colder temperatures, low wind chills and lake
effect snow showers (though growing ice coverage could cut back on
the extent of the lake effect). Temperatures are expected to be 15
to 20 degrees below average for early March.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 639 PM EST Wed Feb 27 2019
Lake effect/enhanced snow showers will continue in the APN area
for a few more hours. As nnw flow gets better established,
expect some snow showers to return to the TVC area tonight. Expect
at least MVFR conditions at times there tonight. Otherwise quieter
wx expected into Thursday, with VFR to MVFR cigs. Light surface
winds tonight, a sw breeze develops Thursday.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
&&
$$
UPDATE...JZ
NEAR TERM...BA
SHORT TERM...AS
LONG TERM...AS
AVIATION...JZ
Area Forecast Discussion
National Weather Service Fort Worth TX
914 PM CST Wed Feb 27 2019
.UPDATE...
A non-trivial forecast update across the area today with a strong
cold front plowing southward through the FA. In general, feel
impacts due to any light freezing rain/light freezing drizzle will
be limited this evening and I do not anticipate the need for a
Winter Weather Advisory at this time.
The much advertised cold front continues to barrel southward down
towards the upper TX coast. Zonal flow aloft, coupled with meager
moisture should keep the potential for widespread measurable
rainfall very low across the area. Where temperatures have fallen
below 32 degrees, there will be a potential for very light
freezing drizzle and this threat appears most likely near and
north of a Comanche to D/FW to Paris line. Impacts should be very
minor across the area and we`ve held off a Winter Weather
Advisory for a few reasons. 1) Recent calls to areas along the
Red River (which have experienced several hours of light FZDZ)
revealed little to no icing of road surfaces...including bridges
and overpasses. 2) RAP forecast 925mb profiles continue to suggest
that slightly drier air may be on the move to the east and
southeast. This is likely resulting in shrinking supercooled water
droplets and this should be detrimental to the risk for
substantial ice accretion rates necessary for widespread slick
spots. 3) In tandem with #2, the strong north winds may also be
helping to limit ice accretion via evaporation. All that in mind,
I can`t rule out a slick bridge or overpass, but we feel that
this potential is conveyed well in graphics and the Special
Weather Statement.
I`ve followed the latest HRRR for hourly and min temperatures and
while this guidance offers the most realistic output, it still
appears a little to slow and subsequent tweaks to hourly
temperatures are likely. Otherwise, updated products will be out
shortly.
Bain
&&
.AVIATION... /Issued 715 PM CST Wed Feb 27 2019/
00 UTC TAF Cycle
Concerns---Ceiling trends and FZDZ potential.
Poor flying conditions will continue tonight before ceilings
slowly improve after midnight. Until then, post frontal IFR cigs
will persist with occasional cloud decks around FL004-FL005.
Visibility may also fluctuate some due to -DZ, but trends suggest
that this may be short lived. Cold air has invaded western
Metroplex TAF sites a little faster than initially thought and
I`ll advertise a brief period of -FZDZ. Light icing will be
possible for idle aircraft. As it pertains to the rest of the
Metroplex TAFs, the possibility of -FZDZ is low (but non-zero) and
I`ll monitor this potential very closely and amend TAFs if
necessary. FZDZ appears unlikely at Waco. Breezy north to
northwest winds of around 15 knots, with occasional gusts to near
20 knots are possible. After midnight, cigs should improve as dry
air aloft invades from the west and northwest. Near or just after
daybreak, VFR with north flow is likely to persist, except at Waco
where MVFR cigs may linger through much of the day. A return to
south flow may be possible, late Thursday into early Friday.
Bain
&&
.SHORT TERM... /Issued 413 PM CST Wed Feb 27 2019/
/Tonight Through Friday/
The main challenge in the near term will be tonight into Thursday
morning, as temperatures fall into the 30s and 40s. The potential
for patchy light fog, drizzle, or even patchy freezing drizzle
from Highway 380 to the Red River and possibly as far south as
Eastland/Stephenville out west. The culprit is a very shallow
arctic airmass expected to remain less than 1000 feet deep that
continues to surge south of I-20 and I-30 in the east as of this
writing. High-resolution models have struggled on the depth of the
arctic airmass, along with showing different projections on any
light drizzle or freezing drizzle potential tonight. The culprit
is in the strength of the west-southwest flow and modest isentropic
ascent just above the frontal inversion in the boundary layer.
This can determine how much drizzle falls into the cold airmass
below. The NAM is the most bullish, with the HREF in the middle,
and the HRRR/GFS not showing much at all.
Per current observations and temperature trends, I`m going middle
ground here, which mirrors our previous forecast very closely
with low chances for showers in our eastern and Central Texas
counties, with patchy fog and drizzle just about everywhere. The
concern continues to be the area noted above that will likely fall
below freezing tonight. Right now, per collaboration with offices
bordering these areas to the north and west, is that any
accretion and expanse of any freezing drizzle is too uncertain for
any Freezing Drizzle Advisory issuance on this package, but
something that certainly needs to be monitored very closely as we
move into the evening hours. Similarly, early Thursday morning
during the morning rush hour just north and west of the immediate
Metroplex is challenging, but for now it appears the dry air will
be arriving along the frontal inversion which should put an end
to any potential and spotty freezing drizzle. Skies will begin to
clear towards midday and temperatures moderate into the upper 30s
and lower 40s. Otherwise, despite the clearing and shallow nature
of the arctic airmass across the area, I`m definitely leaning
toward the colder side of guidance and may be a tad warm, but this
is semantics at this point for high temperatures Thursday as
brisk north winds around 10 mph continue.
Cold surface high pressure settles by Thursday evening, before
sliding east of the area with returning south winds 10-15 mph on
Friday. It will be another chilly morning Friday, but temperatures
should moderate, especially across the western counties in the
higher terrain. How quickly this shallow dome of arctic air
modifies elsewhere is the quandary, especially with the return of
extensive cloud cover associated with a mid level disturbances
moving across the area. I`d stay on the cool side with highs only
in the 50s in the eastern counties. However, as noted before, it`s
possible advertised high temperatures east of I-35 may be too
warm all things considered. Enough moisture will reside across the
far northeast counties for a low chance of light showers, but
nothing of significance.
05/
&&
.LONG TERM... /Issued 413 PM CST Wed Feb 27 2019/
/Friday night and beyond/
There are two main concerns in the extended part of the forecast.
First, we will see another strong cold front moving across the
area this weekend some time late Saturday evening or overnight.
The timing of the front continues to be the tricky part of the
forecast. The GFS continues to move the front a little faster,
shifting the winds during the evening hours (later than the
previous runs suggested). On the opposite side, ECMWF is the
slowest, moving the front across North Texas late Saturday night.
Regardless on when this happens, there is high confidence that
precipitation chances will increase along the front. At this time,
we only expect rain to occur across the area as temperatures will
be well above freezing Saturday/Saturday night. The challenging
part comes on Sunday morning. There will be another push of cold
air, but how much moisture will be available is still uncertain.
If sufficient precipitation can linger behind the system into
Sunday morning, there will be a possibility for some light
wintry-mix precipitation (freezing rain/or sleet) on Sunday. At
this time, thermal profiles suggest freezing rain or sleet
scenario, but again, this will depend on how saturated will be the
atmosphere. For now, the best chance for any wintry precipitation
will be across the north/northwest of the DFW Metroplex. I want
to reiterate that there are a lot of uncertainties with this part
of the forecast and more details will be refined in the upcoming
days.
One thing for sure is the return of the winter-like temperatures
for the early part of the week across all North and Central TX. We
will wake up with temperatures in the 20s and teens (across the
northwest) on Monday morning. Afternoon highs will only be in the
30s and low 40s. Another very cold night (lows in the 20s) is
expected Monday night into Tuesday morning. Expect the cold/cool
but dry conditions to continue through at least the mid part of
the week.
Sanchez
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 32 43 39 61 53 / 20 10 5 10 20
Waco 37 45 38 64 56 / 20 20 10 10 20
Paris 32 44 38 56 49 / 30 20 5 20 30
Denton 30 43 36 59 50 / 20 10 5 10 20
McKinney 31 43 37 60 51 / 20 10 0 10 20
Dallas 33 44 40 62 54 / 20 10 5 10 20
Terrell 35 44 38 61 54 / 20 20 5 10 20
Corsicana 37 45 39 62 55 / 20 20 5 10 20
Temple 37 45 40 67 57 / 20 20 10 10 20
Mineral Wells 30 44 38 64 50 / 10 5 5 10 20
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
24/30
Area Forecast Discussion
National Weather Service Grand Rapids MI
800 PM EST Wed Feb 27 2019
LATEST UPDATE...
Update/Synopsis/Climate
.SYNOPSIS...
Issued at 749 PM EST Wed Feb 27 2019
- Lake effect snow showers west of US-131 tonight
- Accumulating snow possible Friday night into Saturday
- Turning much colder beginning Sunday
- Record Cold possible (see climate section) and lake effect snow
persist into mid next week
&&
.UPDATE...
Issued at 749 PM EST Wed Feb 27 2019
I increased the chance for measurable snow to near 100% this
evening west of US-131 as mesolow moves on shore this evening.
Since this does not look very strong, I do not believe we will see
heavy snowfall rates from this event. None-the-less I could see 1
to locally 2 inch snowfalls as the core of it moves across the
South Haven area mid evening.
We had a mesolow developed over central Lake Michigan as forecast
by the 1km Parallel Dev HRRR had suggested on the 03z run last
night. There is narrow band of colder air moving through early
tonight and this brings an area of strong lift and low level
convergence to the lake shore as this moves through. The time of
the maximum lift and snowfall rates should be in the 9 pm to
midnight time frame. After that the lift decreases as slightly
warmer mid-level air moves in.
&&
.DISCUSSION...(This evening through next Wednesday)
Issued at 328 PM EST Wed Feb 27 2019
Some lake effect snow showers are out over Lake Michigan at 300pm
and these will be pushed inland this evening. We may even see some
wind parallel band show up for a time, as the DGZ becomes
saturated with some weak lift noted as well. Not much in the way
of accumulation is expected as the snow shower will not last long,
but not out of the realm to see trace amounts to a few tenths of
an inch.
The next chance for precipitation comes Friday night into Saturday
as a shortwave in the mid levels slides east out of the northern
plains. This does not look like a significant snow producer. Snow
amounts will likely range from trace amounts toward I-94 to an
inch or two across Central Lower Michigan.
Colder air begins to flow into the Great Lakes region Saturday
night into Sunday behind a cold front. The air is anomalously
cold by March standards and will rival the cold period we had
about a month ago. 850mb temps are forecast to dip into the -22C
to -25C range by both the operational ECMWF and GFS. So air
temperatures will at least be in the teens F for highs, with
single digit highs not out of the question. A rare event by March
standards for sure. The coldest high temperature on record in the
month of March in Grand Rapids is 10 degrees, which is the ECMWF
MOS high temp on Monday at GRR.
Lake effect snows are expected from Sunday into Wednesday as the
upper trough slowly moves through the Great Lakes. Accumulations
will likely be limited given the very cold temps. The DGZ via the
GFS is forecast to be shallow in depth and located below 3,000ft.
Flake size will be small. It does not take much snow though to
cause issues at these temperatures as it is typically ground down
by cars into a fine sheen of ice. Salt does not work well, so
travel is usually impaired significantly. Sunday through Tuesday
and possibly into Wednesday looks to contain these conditions,
especially from Highway 131 to the west. A significant shortwave
is seen in both the GFS and ECWMF Monday night at this could be a
time frame to watch where the lake effect snow could significantly
flare up.
Bottom line, the forecast is fairly quiet from Tonight through
Saturday and turns very winter like from Sunday into next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 702 PM EST Wed Feb 27 2019
As noted in the discussion there is an area of snow showers moving
in shore into our western TAF sites (MKG, GRR and AZO). It`s
likely BTL will also see the snowfall this evening. At those sites
expect MVFR and occasionally IFR in snow showers until after 06z
when we expect the moisture to be more limited and the snow
showers may come to an end. Due to northwest winds at cloud level
I expect the western TAFs stay overcast but ceilings become VFR.
The eastern TAf sites may actually clear later this evening due to
that same northwest wind bringing down drier air.
&&
.HYDROLOGY...
Issued at 328 PM EST Wed Feb 27 2019
Most of the rivers in our area have crested from the rain and
melting snow last weekend. The Grand River, from Grand Rapids down
to Lake Michigan, will continue a very slow rise for another day or
two before beginning to fall. As colder than normal temperatures
continue for the next week, we won`t be adding much more water to
any of the rivers, so the general trend in water levels will be
downward.
We continue to monitor river ice conditions around the area. No new
ice jams have formed, and some of the areas that did have solid ice
cover remaining in place are showing more and more signs of open
water and a gentle breakup (no ice jams). The one exception is
Portland, where several ice jams continue to affect the city, and
where water levels could still fluctuate with little or no warning.
Looking ahead to next week, it is starting to look like a return of
bitter cold temperatures for the first half of next week. Even
though many of our rivers are now ice-free, a return to arctic
temperatures will kick ice growth on the rivers into overdrive.
There could be some locations that experience complete ice freeze-up
again, which brings with it the possibility of new ice jams. Anyone
living or working near our rivers will need to pay extra attention
early next week, in case water levels start to rise.
&&
.CLIMATE...
Issued at 749 PM EST Wed Feb 27 2019
Record Temperatures for March 3-6 (Sunday through Tuesday)
Record Low Temperatures March 3
Grand Rapids -9 (1943)
Lansing -19 (1968)
Muskegon -10 (1943)
Kalamazoo -12 (1943)
Record Coldest High Temperatures (low max) for March 4
Grand Rapids 12 (1943)
Lansing 11 (1943)
Muskegon 15 (2014)
Kalamazoo 12 (1943)
Record Low Temperatures March 4
Grand Rapids -3 (1948)
Lansing -17 (1868)
Muskegon -2 (1912)
Kalamazoo -3 (2002)
Record Coldest High Temperatures (low max) for March 4
Grand Rapids 13 (2002)
Lansing 15 (2002)
Muskegon 19 (2002)
Kalamazoo 11 (2002)
Record Low Temperatures March 5
Grand Rapids -8 (1948)
Lansing -7 (1895)
Muskegon -5 (1949)
Kalamazoo -1 (1926)
Record Coldest High Temperatures (low max) for March 5
Grand Rapids 16 (1920)
Lansing 17 (2015)
Muskegon 17 (2015)
Kalamazoo 19 (1900)
Record temperatures for the month of March:
Record Low Temperatures for March:
Grand Rapids -13 (March 8 1943)
Lansing -25 (March 2 1868)
Muskegon -11 (March 16 1897)
Kalamazoo -12 (March 3 1943)
Record Coldest High Temperatures for March:
Grand Rapids 10 (March 2 1925, March 17 1941)
Lansing 6 (March 20 1885)
Muskegon 12 (March 1 1962, March 8 1996, March 16 1900, March 17 1941)
Kalamazoo 11 (March 4 2002, March 8 1932)
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...WDM
SYNOPSIS...WDM
DISCUSSION...Duke
AVIATION...WDM
HYDROLOGY...AMD
CLIMATE...HLO
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
847 PM CST Wed Feb 27 2019
.UPDATE...
Issued at 838 PM CST Wed Feb 27 2019
Latest guidance, including the 00z/28 NAM, continues to push
precip further north into the CWA tonight and through Thurs
morning. Have therefore trended forecast further north as well,
including the Advisory. The NAM brings strong WAA and moisture
convergence through about mid sections of the CWA through mid day
Thurs.
A few questions remain on this update. First, this northward
expansion may still not be far enough north, but should include
the areas that will see the larger impacts during the morning rush
hour. However, this precip may linger longer into the afternoon
hours across far eastern portions of the CWA. This will need to be
updated as confidence increases, but have raised PoPs into the
high chance range.
Precip type also becomes questionable further north. Model
soundings suggest that precip along the northern edge may begin as
sleet. As the warm wedge aloft cools, this is expected to at
least briefly change over to FZRA/DZ. However, if the low level cold
air is resolved correctly by models, this may change over to snow
quicker than currently forecast. Have kept this mainly as FZRA/DZ
thinking the NAM is too cold in low levels, but will need to
continue to monitor.
Tilly
&&
.SHORT TERM... (Through Late Thursday Afternoon)
Issued at 306 PM CST Wed Feb 27 2019
The primary forecast challenge for the short term continues to be
the light freezing rain/freezing drizzle for tonight and Thursday
morning across parts of southeast Missouri. A 1035mb high centered
over the eastern Great Plains is pumping cold air down into the Mid
Mississippi Valley. Temperatures have been falling behind the cold
front on the leading edge of this cold airmass today, and this
downward trend will continue tonight with lows bottoming out in the
mid teens in northeast Missouri and west central Illinois to the low
and mid 20s across southeast Missouri and southwest Illinois. These
sub-freezing temperatures will set the stage for wintry
precipitation tonight and Thursday morning. Models are showing a
weak 500mb shortwave moving into the eastern Plains tonight, and
this wave helps to push an 850mb trough from the Great Plains
through the Mississippi Valley tonight and Thursday. All short
range guidance is showing some weak low level warm advection and
frontogenesis to a greater or lesser extent as well as a nearly
saturated 925-850mb layer across southern Missouri and Illinois
tonight ahead of the 850mb trough. Low level moisture drops off
quickly further to the north in all models except the RAP which
actually keeps the layer near saturation all the way up to the I-70
corridor. However, a closer look at RAP forecast soundings shows a
fairly deep (~1500 ft) dry layer near the surface extending at least
through Jefferson County Missouri...so I think the RAP may be too
aggressive with it`s northward push of QPF tonight. Have stuck with
likely PoPs across the eastern Ozarks and into Randolph County
Illinois for primarily freezing drizzle, but the aforementioned dry
layer along with the very cold air in the boundary layer pushing in
from the north may generate a few sleet pellets as well. The Winter
Weather Advisory will be extended east into Randolph County Illinois
to cover the higher chance of accumulating ice now in the forecast.
Up to about 0.01 inch of ice is possible in spots...but most areas
will likely see 0.02 to 0.05 inch...just enough to make untreated
surfaces very slippery.
The wintry precipitation should end during the morning on Thursday,
and there should be some warming during the day as clouds thin and
shift eastward behind the shortwave. Ensemble guidance in the low
to mid 30s looks reasonable with at least partial sunshine in the
afternoon. Cold temperatures will continue on Thursday night as the
Great Plains high shifts into the Midwest with lows dropping again
into the teens and 20s.
Carney
.LONG TERM... (Thursday Night through Next Wednesday)
Issued at 306 PM CST Wed Feb 27 2019
Friday looks like a rather tranquil day. A low amplitude short wave
within the quasi-zonal flow aloft will result in high clouds across
the area while low level temperature advections suggest some weak
WAA from the morning into the afternoon. Temperatures should be
seasonable, trending a bit below normal. A cold front will then drop
south through the region Friday night bringing our initial shot of
colder air.
A more active winter weather pattern resumes this coming weekend as
we begin to see signs of impending large scale amplification as an
upper low near Lake Winnipeg sinks east-southeast into Ontario,
resulting in a more broadly cyclonic but continued fast flow aloft
across much of the Nation. Current indications are we will see
wintry precipitation this weekend as a series of disturbances in the
fast flow aloft traverse the region. I think the main questions are
the when and where? The GFS remains the sole model wanting to
develop precipitation across the area as early as late Saturday
morning into the afternoon in two primary areas - a narrow band
across the far northern CWA in response to mid level frontogenetic
forcing and a zone of precipitation centered across southeast MO and
southern IL in response to low-mid level frontogenetic forcing and
weak WAA. While the ECWMF has WAA, it along with the NAM both lack
the frontogenesis component and associated forcing. As such,
confidence in precipitation during the day Saturday is low with only
chance pops across the southern CWA where thermal profiles would
suggest predominately rain, possibly changing to a rain/snow mix.
There is better consensus among the models for a formidable winter
storm system with accumulating snow Saturday night into Sunday. Both
the GFS and ECMWF show several short waves traversing the area with
the strongest on Sunday. Impressive baroclinicity is indicated aloft
with results in good low-mid level frontogenetic forcing. This
forcing when combined with large scale ascent with the upper waves,
should lead to widespread snow starting Saturday night, continuing
Sunday morning, then coming to an end on Sunday afternoon as the
last wave passes by. The ECMWF is the strongest model and further
north with the baroclinic zone, track of the surface and 850 mb
lows, and corresponding thermal advections and forcing. In fact, its
forcing, QPF, and anticipated LSRs would suggest the potential for a
warning level event. Its slightly more northerly track would also
have some wintry mix over the far southern CWA on Saturday night. At
this point we have ramped up the pops and have begun messaging the
likelihood of accumulating snow.
The period from late Sunday night through early next week looks down
right cold as a deep but broad upper trof dominates the eastern half
on the CONUS and strong surface high pressure moves slowly eastward
from the Plains. Fresh snow pack will only add to the magnitude of
the expected cold, especially for overnight lows. I have tweaked
down the temperatures from the previous forecast and present
indications are temperatures will range from 20 to 30 degrees below
normal for early March.
Glass
&&
.AVIATION... (For the 00z TAFs through 00z Thursday Evening)
Issued at 522 PM CST Wed Feb 27 2019
Focus for tonight into Thurs will be determining if MVFR cigs will
move back north to impact KCOU and if precip will accompany those
lower cigs. For now, have kept trends similar to the prev
forecast, but did add mention of a scattered 2000 ft deck to
indicate the potential for lower cigs. Otherwise, expect VFR
conditions to prevail with northerly to northeast winds through
the period.
SPECIFICS FOR KSTL/KSUS/KCPS: Main question for this forecast
package will be if MVFR cigs move back into the area and if
freezing rain will accompany those cigs. For now, have only added
a scattered MVFR deck, but will need to continue to monitor for
further changes. These MVFR cigs will likely remain in place
through Thurs morning. Otherwise, winds will remain north to
northeast through the period.
Tilly
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 22 33 26 45 / 30 60 5 5
Quincy 14 30 19 41 / 5 5 0 5
Columbia 18 31 22 45 / 30 30 0 10
Jefferson City 20 33 22 46 / 50 50 0 10
Salem 24 34 26 44 / 20 40 5 5
Farmington 24 33 24 46 / 80 80 5 10
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...Winter Weather Advisory until noon CST Thursday for Crawford MO-
Iron MO-Madison MO-Reynolds MO-Saint Francois MO-Sainte
Genevieve MO-Washington MO.
Winter Weather Advisory from midnight tonight to noon CST
Thursday for Cole MO-Franklin MO-Gasconade MO-Jefferson MO-
Moniteau MO-Osage MO-Saint Charles MO-Saint Louis City MO-
Saint Louis MO-Warren MO.
IL...Winter Weather Advisory until noon CST Thursday for Randolph IL.
Winter Weather Advisory from midnight tonight to noon CST
Thursday for Bond IL-Clinton IL-Madison IL-Monroe IL-Saint
Clair IL-Washington IL.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
539 PM EST Wed Feb 27 2019
.SHORT TERM...(This evening through Thursday)
Issued at 223 PM EST WED FEB 27 2019
Shallow troughing across the northeastern US will continue to modify
and become zonal late tonight. In the meantime, the shortwave and
associated vort max continues its trek across the Upper Peninsula
this afternoon. Much of the widespread snow ended earlier today, and
we were a bit surprised to see nearly 10:1 SLRs out of it. Some
additional light snow is ongoing over the central and eastern UP,
with a heavier upsloping band of fluffier snow across eastern
Marquette County that may add up to an inch or so. Indications in
the HRRR and RAP continue that a band of moderate snow of a more
convective nature will develop across Luce, Schoolcraft, and eastern
Delta Counties this afternoon into the early evening. However,
they`ve cut back on expected QPF the last couple of runs so the
forecast has been edited accordingly. Beginning to see a more
cellular nature in the radar returns, so this seems relatively
feasible. Overall, expecting a maximum of 2 to 3 inches of snow out
of this, attributable to a fluffier nature this time around.
Despite the larger hydrometeors this afternoon, a few brief
reductions in visibility will be possible, as well as continued
slick spots on the roads, so an SPS is out to cover the threat
through the evening commute.
After the passage of this shortwave, some lingering lake effect over
the far northeastern UP will continue through just after midnight,
with 850 mb temps of -18 to -20. But this activity will be pulling
offshore as winds shift to the W and SW overnight. Skies are
expected to become mostly clear for the central and western UP as
high pressure over the plains slowly pushes eastward. With winds
lightening up and some additional new snow on the ground, pretty
efficient radiation will allow temps to drop below zero for most
inland locations, and into the minus teens over the usual cold
spots. Wouldn`t be surprised to see a few -20 readings if complete
decoupling occurs.
Thursday, generally benign weather is expected but a few light
flurries can`t be ruled out over the Keweenaw where some upsloping
is possible. Some sunshine and southwesterly flow will bring back
some warmer temps, with highs expected into the low to mid 20s. A
few upper 20s would not surprise me given the sun angle and some
downsloping over the north central.
.LONG TERM...(Thursday night through Wednesday)
Issued at 353 PM EST WED FEB 27 2019
Continued cold pattern through the extended forecast as temperatures
will be running 10 to 15 degrees below normal, with the exception of
Thurs/Fri this week. Extensive ridging over the Pacific looks to
continue as GEM ensemble spaghetti plots hold on to a ridge over the
Pacific and trough through the central and eastern CONUS. This idea
is mirrored by the CFS 850mb temperature model as well. ECMWF 500-mb
continues a negative height anomaly through the central CONUS
for the next 8 to 10 days. The GFS 500-mb height anomaly
continues with the ridge/trough pattern into mid- March, putting
Upper Michigan in the transition zone as the ridge and trough move
slightly to the east.
Current GOES imagery shows the vast majority of western Lake
Superior as ice covered which will continue to limit lake-effect
snow showers for western Upper Michigan through the forecast period,
or until the ice begins to break up. Open waters over eastern Lake
Superior are still producing some cloud development. With this
current coverage, any lake-effect snow showers will be limited out
west.
On Thursday night, clear skies and lighter winds look to bring low
temperatures into the single digits below zero, especially out west.
NAM soundings show inversion and moisture heights topping out
near 4000 ft. Combine this with weak heat flux from Lake Superior
and it creates minimal snowfall chances outside of a few
flurries.
Friday evening, a shortwave trough will begin to move into Upper
Michigan. The 12Z GFS run brings the higher axis of QPF along a line
from KRST to KGRB, with anywhere from 0.10 to 0.15 inches of QPF
throughout the CWA. 12Z FV3 runs bring slightly more QPF than that,
with 12Z NAM runs running fairly consistent with the GFS. With
current SLR values going near 20:1, a widespread 2-3 inches looks
likely throughout the CWA. As the shortwave passes by, NW wind lake-
effect will begin to add additional snowfall values with model 850
temps falling from -15C towards -20 and even -25C as colder air
fills in behind on Sunday.
West to northwest flow will then continue as the this ridge/trough
pattern continues. This will lead to at least chance PoPs through
Thursday in the W to NW wind snow belts. With increased winds on
Sat/Sun this weekend, shifting ice will be one component to keep
your eyes on as that will be the biggest factor on LES development
with 850-lk sfc delta Ts reaching at least 15 degrees after
Sunday through Wednesday morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 539 PM EST WED FEB 27 2019
VFR conditions will continue at all sites through this forecast
period. Only exception is SAW really early this forecast with lake
effect snow showers moving out.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 223 PM EST WED FEB 27 2019
On Lake Superior, winds will remain below 25 knots into Thursday
afternoon, when the western lake may see a few 30 knot gusts.
Conditions will calm down on Friday before winds increase to 25-30
kts Sat night into Sun, mainly over the east. A few 30 knot gusts
will remain possible over the east into Sunday night, with winds of
15 to 25 knots expected on Monday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...KCW
LONG TERM...JAW
AVIATION...07
MARINE...KCW
Area Forecast Discussion
National Weather Service Blacksburg VA
744 PM EST Wed Feb 27 2019
.SYNOPSIS...
High pressure over the northeast will wedge southward into
tonight. A frontal boundary stays in the vicinity of the region
through Friday. A cold front will cross the area this weekend
followed by a wave of low pressure that looks to bring mainly
rain ahead of a surge of Arctic air that will arrive next week.
&&
.NEAR TERM /THROUGH THURSDAY/...
As of 210 PM EST Wednesday...
High pressure over New England will slowly slide east tonight into
Thursday. A weak shortwave riding along the frontal boundary will
exit this evening into tonight. The HiResW-ARW-E and HRRR showed a
small chance for light rain across southern portions of the forecast
area.
The upper flow backs late tonight into Thursday morning. Another
wave of low pressure riding the frontal boundary toward the southern
and central Appalachians will result in scattered showers mainly in
the western mountains. There is a small chance for some freezing
drizzle along the western slopes in northern Greenbrier county in
West Virginia. Shaped pops towards the NAM for tonight into Thursday
morning. Low temperatures tonight will range from the lower 30s in
the northern mountains to the lower 40s in the piedmont.
Another area of low pressure will ride northeast along the front
Thursday resulting in overrunning rain. Rain will start in the west
and spread northeast across our area Thursday. High temperatures on
Thursday will vary from the lower 40s in the northwest mountains to
around 60 degrees in southeast.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
As of 200 PM EST Wednesday...
Fast zonal flow aloft will persist through much of the period with
passing southern stream waves crossing the region but basically
split from too much northern stream interaction at this point.
However models have come around to a bit stronger surface feature
Thursday night into early Friday with fractured southern energy
enhanced a bit via a trailing northern stream shortwave that will
cross the region late Thursday night. This along with weak upslope
southeast flow aloft aided by an inverted surface trough across the
west may tend to produce more lift and at least a period of steadier
rainfall mainly overnight. Will also have weak cold high pressure to
the northeast as the wedge deepens allowing for easterly flow to
help cool the column just above the surface per latest forecast
soundings. This below a pronounced warm nose below 85h that looks
typical of a elevation based icing event on the ridges.
Since guidance also trending colder, bumped up icing across the
north Thursday night while extending a band down the eastern slopes
of the Blue Ridge to Floyd county by early Friday similar to an
event a couple weeks ago. Appears icing mainly on elevated surfaces
but if colder trends continue then may need an advisory near the I-
64 corridor. Otherwise continuing high pops Thursday night into
Friday morning for a quarter to half inch QPF event with lows 30s to
around 40 except below freezing in spots on the ridges. Therefore
after reducing pops some Friday behind the main impulse, ramped up
some espcly Blue Ridge Friday night for additional light precip with
highs only in the chilly 40s.
Impulse exits Friday but the forecast remains uncertain into Friday
night as the wedge holds while additional weak waves aloft likely
cross the region above the residual inverted trough. This along with
lingering light easterly flow may result in spotty light rain or
drizzle into Friday night when could again see some isolated
locations across the north dip below freezing again.
Saturday should see a transition from the lingering wedge as a weak
warm front drifts north and a cold front arrives from the west.
Latest models showing less deep moisture with these features as main
upper support lifts to the northeast while low pressure slides
offshore. This may leave the region in a void although some overall
chance pops likely needed into Saturday night at this point espcly
west late Saturday night with the next wave approaching along the
boundary. Highs should bounce back into the 40s/50s Saturday and not
fall too much overnight pending the exodus of the wedge.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
As of 210 PM EST Wednesday...
Surface cold front will spill south of the area Sunday but will less
push than seen yesterday as held up by southwest flow aloft and
subsequent digging of upstream shortwave troffiness to the west.
Current model solutions have now trended toward the earlier warmer
ECMWF in sharpening up energy to the west while having a bit less
positive tilt that may eventually allow some phasing to take shape
by Sunday night. This should put much of the area closer or into the
warm sector as the surface low tracks along or perhaps just west of
the Blue Ridge later Sunday before quickly exiting Sunday night as
much colder air with the Arctic high to the northwest chases in.
Since most of the deeper cold air with this scenario will be to the
northwest, looking at mostly rain Sunday with perhaps some snow
across the higher elevations of the far northwest espcly later in
the day. However once the surface low departs, colder air will try
and surge in and catch remaining moisture, perhaps allowing for a
change to snow at the end from northwest to southeast but iffy pending
the track at this point. Otherwise running with high pops Sunday/Sunday
night, then quickly drying out by Monday afternoon with dry but
cold weather through midweek with the coldest day Wednesday when
highs likely to stay below freezing mountains.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 730 PM EST Wednesday...
VFR conditions are expected to prevail at all sites through much
of the TAF valid period. A wedge will encroach on the area from
the northeast bringing a northeast to east wind to much of the
forecast area by Thursday afternoon. Meanwhile, a series of
upper-level disturbances will track across the area from the
west. Clouds will continue to increase and lower with time,
dropping into the MVFR category by morning in the west and
evening in the east. Light rain showers will impact mainly the
western areas, west of the Blue Ridge, early Thursday with some
minor chance for freezing rain in the far north (e.g., Bath
County). The next upper-level disturbance will approach late in
the day with increasing chances for rain by evening across the
entire CWA accompanied by MVFR to IFR visibilities and IFR-LIFR
ceilings. Winds will be light and variable through Thursday
morning, becoming east to northeast 5-10 mph as the wedge
intensifies after daybreak Thursday.
/Confidence in Forecast Parameters/
Ceilings - Moderate to High,
Visibilities - Moderate to High,
Winds - Moderate to High.
EXTENDED AVIATION DISCUSSION...
Friday expect a higher probability of precipitation and MVFR
conditions as a low pressure system crosses the southeast United
States. Scattered MVFR/IFR rain and snow showers are possible
on Saturday as cold air spreads into the area. Widespread rain
and snow will result in MVFR/IFR conditions by late Sunday into
Monday. Drier and much colder air will result in improving
conditions, especially east of the Blue Ridge after Monday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK
NEAR TERM...KK
SHORT TERM...JH
LONG TERM...JH
AVIATION...KK/RAB/WP
Area Forecast Discussion
National Weather Service San Diego CA
145 PM PST Wed Feb 27 2019
.SYNOPSIS...
A weak trough of low pressure will bring light precipitation
southwest California late tonight into Thursday. Friday will be a
dry day under weak high pressure aloft. Another trough moving inland
across California will bring greater chances for light to moderate
precipitation over the weekend. Monday and Tuesday will be mostly
dry, but another trough with more precipitation is likely on
Wednesday.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Light rain over San Barbara and Ventura Counties hasn`t made any
progress moving south since this morning. The 6-hour rain totals
through 1 PM ranged from 0.01"-0.10" with higher values near 0.20"
in the higher terrain. A peak value of 0.27" was observed at West
Big Pine. A small moisture plume ahead of the surface trough raised
the PW to 0.93 on the 12Z Vandenberg sounding. Farther south at NKX
the PW was 0.60". The trough will weaken as it moves south into a
drier, more stable airmass, and that bodes poorly for precipitation
amounts down here. The HRRR model output shows only 0.01-0.10" in
the Orange County and the Inland Empire. Amounts are even lower in
San Diego County, especially in south county where amounts will
likely be 0.00"-Trace. Highest amounts close to 0.20" are possible
on the south slopes of San Bernardino mountains from
orographics.
Friday will be mostly dry under weak high pressure aloft. Onshore
flow will continue to bring periods of gusty southwest to west winds
for the mountains and deserts.
On Saturday a stronger trough with PVA and weak cold air advection
will move inland across Southern California. Precipitation will
start out over western San Bernardino Mountains and Orange County in
the predawn hours, then move across the Inland Empire and San Diego
County through midday. The PW with this system will be higher than
the on Thursday, from 1.10 to 1.20", and that added moisture along
with the stronger upper support will wring out more rain over and
west of the mountains and the high deserts.
The rain totals for Orange, southwestern San Bernardino, and western
Riverside Counties haven`t changed much from this morning ranging
from 0.20"-0.50" in the coastal and valley areas. The exception will
be the rain shadowed areas of the Inland Empire from Perris
southward to Temecula, including the cites of Sun City, Hemet and
Lake Elsinore where only 0.05"-0.15" are likely. The mountains will
see the highest amounts of 0.50"-1.00".
Farther south in San Diego County, rain amounts will be highest in
north county (0.10" to 0.30") and lower in south county (0.05"-
0.20"). In the high deserts, 0.05" to 0.15" is expected, and the
lower deserts will see Trace amounts to a max of 0.10" in northern
Coachella Valley. Snow levels above 8,000 feet Friday night will
lower to around 7,000 feet Saturday night with a few inches of
snowfall above 7500 feet. Scattered showers will continue in the
colder and modestly unstable airmass behind the front on Sunday,
mostly along and west of the mountains.
The pattern remains active through next week with two Pacific
shortwaves bringing more precipitation, the first on Wednesday and
the second on Friday/Saturday, March 8th-9th.
&&
.AVIATION...
272100Z... Scattered high clouds with unrestricted vis through this
afternoon. Low clouds to develop after 03Z Thursday with bases
around 2500-4000 feet MSL and tops to 6000 feet. Isolated SHRA after
08Z, most likely around KSNA-KONT. Showers will exit the region
after 18Z Thursday, with SCT-BKN low clouds likely sticking around
throughout the period.
&&
.MARINE...
No hazardous marine weather is expected through Sunday.
&&
.SKYWARN...
Skywarn activation is not requested.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&
$$
PUBLIC...Moede
AVIATION/MARINE...Connolly
Area Forecast Discussion
National Weather Service San Angelo TX
919 PM CST Wed Feb 27 2019
.UPDATE...
Have updated the forecast for colder temperatures tonight. The
cold front has moved south of the Interstate 10 corridor, and
temperatures are colder than previously thought area-wide. Have
trended temperatures for the rest of the overnight hours very
closely to the HRRR values, with this model being closest to
reality, but still had to shave a few degrees off this data as
well. Haven`t had any precipitation out of the air mass, but
visibility values are starting to come down along/north of the
I-20 corridor, and we will continue to watch observations
closely. 20
&&
.PREV DISCUSSION... /issued 602 PM CST Wed Feb 27 2019/
AVIATION...
/00Z TAFS/
A cold front is currently moving southward across West Central
Texas and will approach the I-10 corridor in the next hour. LIFR
cigs continue to impact KABI while VFR conditions prevailing
across the remaining terminals. Will indicate a graduate
improvement to MVFR cigs at KABI overnight while MVFR cigs develop
across the remaining terminals. Cigs may briefly lift to VFR on
Thursday afternoon, but forecast confidence is low.
PREV DISCUSSION... /issued 251 PM CST Wed Feb 27 2019/
SHORT TERM...
(Tonight and Thursday)
A cold front is currently over the southern Big Country and
continues to move south, with winds behind it turning out of the
north at 10 to 20 mph. Overcast clouds developed behind the front,
as well as much colder conditions this afternoon, with
temperatures down into the mid 30s to low 40s, while temperatures
are warm ahead of the front (mid to upper 70s, and even the low
80s in the Hill Country). Some patchy fog is also occurring in the
Big Country behind the front.
The NAM seems to be doing best job with forecasting the movement
of the front, so have trended down with the overnight temperatures
and the high temperatures for Thursday (the NAM shows the area
remaining chilly tomorrow while the other models show today`s cold
front moving back into the area as a warm front). Thus, current
forecast shows lows tonight in the 28-31 degree range in the Big
Country, mid to upper 30s in the Concho Valley and Heartland, and
40s in the I-10 corridor. With freezing/below freezing
temperatures expected during the late night hours in the Big
Country and the potential for isentropic lift to create some very
light precip/drizzle across the forecast area, patchy freezing
drizzle is not out of the question. Elsewhere, the form of any
precipitation will be rain. Expect gradual clearing of clouds from
west to east tomorrow afternoon.
LONG TERM...
(Friday through Thursday)
The main highlights of the long term forecast remains the strong
cold front that will pass through the region over the weekend.
This combined with an embedded disturbance aloft will provide much
colder temperatures and a chance for precipitation. It remains
highly uncertain at this time, but a chance for frozen
precipitation is included on Sunday morning. Temperature readings
across the Big Country may be in the teens on Monday and Tuesday
morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 29 49 44 74 / 20 5 5 5
San Angelo 36 57 50 78 / 20 10 5 0
Junction 47 59 51 77 / 20 20 10 0
Brownwood 34 47 43 74 / 20 10 5 5
Sweetwater 28 55 45 75 / 10 5 5 0
Ozona 44 64 53 76 / 20 10 5 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Thursday)
Issued at 254 PM CST Wed Feb 27 2019
Broad troughing noted on water vapor imagery this afternoon is
shifting east across the western conus. Strong 1030 mb sfc ridge
currently centered over South Dakota is gradually surging southward,
allowing the stratus to erode over northeast Kansas this afternoon.
Confidence is moderate for the clearing line to reach at least the
Interstate 70 corridor by early evening. Skies become mostly clear
north of Interstate 70 this evening as the ridge axis shifts towards
eastern Nebraska. Temps were lowered near the Nebraska border,
combined with the snow cover and clear skies result in readings in
the single digits. Wind chill readings along and north of highway 36
are likely to be as much as 10 degrees below zero. Elsewhere, lows
in the teens are more common with mostly cloudy skies expected
towards east central areas. Within the broad upper troughing, weak
embedded lift develops additional light, freezing precip this
evening towards southeast Kansas into southern Missouri. Latest HRRR
and RAP runs have been consistent with precip reaching as far north
as Coffey and Anderson counties. Forecast soundings show decent lift
within the column and dry air holding in the ice growth layer,
suggesting the potential for light freezing drizzle. However, this
may mix with light snow given the temp profiles within the 850 to
925 mb layer being up to 10C below zero. No accumulations are
expected with precip ending before sunrise Thursday.
An additional upper trough misses the area to the north on Thursday
as high pressure remains in control characterized by light winds and
partly sunny skies. Adjusted temps to the lower 20s to account for
snow cover in the northern areas, but overall warmer readings
elsewhere in the low 30s.
.LONG TERM...(Thursday night through Wednesday)
Issued at 254 PM CST Wed Feb 27 2019
Extended period focuses on the potential for accumulating snow on
Saturday night and Sunday, followed by an arctic airmass to bring
bitterly cold temps to the region.
Main change from yesterday is that model guidance is more consistent
between each other in terms of timing and location of heaviest qpf.
An initial wave is progged to bring light snow to southern Nebraska
and portions of north central Kansas by Saturday morning. In north
central areas, little to no accumulations are anticipated. The main
vorticity max arrives Saturday evening through Sunday morning with
the bulk of the qpf occurring over the CWA in a short period of
time. Snow is the predominant precip type given the saturated growth
layer and wetbulb temps aloft in the 8 to 13C below zero range
Sunday morning. Snow ratios are on the high side given the cold
airmass in place with a range from 14 to 18:1. And while moisture
availability is still uncertain this far north with ample precip on
the southern end of the system, up to a quarter inch of qpf easily
translates to a few inches of snow by Sunday late morning. If there
is a bit more moisture content to work with, higher snowfall totals
may be realized. Once again, this system is likely to have an impact
on travel for portions of the region. Those planning to travel on
Sunday should continue to pay close attention to this system as
additional model guidance becomes available in the coming days.
Confidence remains high for the 1040 mb sfc ridge to invade
southward Sunday into early next week. Temps across the board were
lowered to account for the snow cover and cooler trends exhibited by
both the GFS and ECMWF. Highs are overall in the lower to middle
teens Sunday and Monday, reaching the 20s by Tuesday. The coldest
day appears to be Monday morning with readings from 5 to 10 below
zero for actual temperature. Wind chill readings are therefore from
12 below zero to 20 below zero for the entire CWA.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 531 PM CST Wed Feb 27 2019
For the 00z TAFs, MVFR cigs will scatter out early this evening,
with VFR conditions expected through the remainder of the TAF
period. Northerly winds also will diminish early this evening,
remaining at less than 10 kts for the remainder of the period.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Prieto
LONG TERM...Prieto
AVIATION...Hennecke