Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 11/15/22
Area Forecast Discussion
National Weather Service Quad Cities IA IL
821 PM CST Mon Nov 14 2022
.UPDATE...
Issued at 817 PM CST Mon Nov 14 2022
While no changes are being made to messaging at this time. It`s
worth noting that models combination of weak forcing, and dry air
found on our soundings below 700mb found on both DVN and ILX
soundings tonight suggest the greatly lowered model QPF of the 00z
model suite so far, which is generally 0.10 to 0.20 compared to
higher values on earlier runs. Combine this low qpf, with marginal
daytime temperatures for accumulation, and we could be looking at
a lower end event than forecast.
ERVIN
&&
.SYNOPSIS...
Issued at 345 PM CST Mon Nov 14 2022
A very energetic upper air pattern is noted across NOAM.
An upper level low was positioned over Manitoba with a
plethora of embedded shortwaves in the large broad upper
trough across the central and western CONUS. One wave
is currently lifting to our north across MN, and has been
responsible for depositing snow on the order of 1 to 3
inches in some areas from SD into MN, NW IA and WI.
Another more robust shortwave was noted lifting out across
OK/TX, with convection developing on the southern flank
along the TX Gulf Coast into Louisiana, and snow - heavy at
times - on the cold side across OK into portions of KS.
It`s this shortwave that will continue to eject northeastward
and aid in bringing the first widespread snow accumulations
of the season over the next 24+ hrs.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 345 PM CST Mon Nov 14 2022
Key Message:
First widespread and prolonged mainly light accumulating snow
expected later tonight through Wednesday with minor impacts.
Discussion:
Snow is expected to gradually develop from south to north tonight
and Tuesday, as the aforementioned shortwave ejects up across the
Mid-Mississippi Valley reaching the southern Great Lakes region
on Tuesday. Winter weather advisories have been issued for late
tonight and Tuesday in collaboration with neighbors with it being
the first widespread accumulating snow, albeit fairly light, and
potential minor impacts (reduced visibility, slick spots on roads
and bridges) to both morning and evening commutes on Tuesday.
This system will be followed up by the remnants of the Manitoba
low diving south across the area on Wednesday bringing a renewed
round of light snow/snow showers.
Forcing for ascent is modest between both rounds and model liquid
QPF is fairly consistent at around 0.1 inch to upwards of around
0.2 inch through Wednesday. SLRs anticipated to be around climo or
a bit warmer at 10-13:1 on Tuesday, and a little colder
potentially on Wednesday. This would support a general 1-2 inch
snow event between both waves of snow. A big factor to consider
for accums will be warm ground/pavement temps, which along with
lower snowfall rates in general of 0.25 to 0.5 inch/hr (DGZ less
than 100 mb and lift weak) will likely allow for melt/compaction
especially during the days both Tuesday and Wednesday. The Fgen
signal is still pronounced tonight into Tuesday AM clipping our
far south, and especially further south where we could see some
higher 3+ inch amounts. There is also a signal for mesoscale band
farther NW into Tuesday evening into portions of eastern Iowa with
overlap of low level Fgen and deformation into a lowering DGZ.
This could lead to a swath of 3+ inch amounts into NE Iowa along
700-600 hPa deformation, and will need to be monitored for
possibly an extension of the advisory in some areas mainly north.
Much of the snow accumulation occur on grassy/elevated surfaces,
as the lift is fairly weak/broad in the DGZ to overcome the
still marginal/warm ground. Roads will have the best potential to
see impacts - slick/snow covered - late tonight/Tuesday AM south
of I-80, and then again Tuesday night possibly into Wed AM
areawide with next round as temps dip below the freezing mark
during these periods. However, elevated bridge decks will be at
the potential for slick spots throughout the prolonged light snow
event. This for many will be the first taste of winter driving in
some time, thus largely the reason for the winter weather
advisory. There`s also the potential Tuesday night to loose in-
cloud ice for a time ahead of the next wave, which could support
some freezing drizzle. Confidence is too low as the window of
opportunity looks to be fairly limited.
.LONG TERM...(Wednesday night through Monday)
Issued at 345 PM CST Mon Nov 14 2022
Key Message:
Well below normal temperatures continue through the period.
Discussion:
We look to keep a highly amplified pattern across NOAM through
the period with a western ridge and eastern CONUS trough.
This will foster continued periodic bouts of reinforcing cold
air, initially the coldest of the season by late week with
highs in the teens/20s and lows in the single digits for some.
The strong arctic front ushering in this cold air on Thursday
could be accompanied by some snow showers, which could be
capable of bringing periods of very low visibility by Thursday
PM, especially east of the Mississippi River based on current
frontal timing.
Beyond the forecast is largely dry but can`t rule out flurries,
and perhaps even chances for some light snow which are not able to
be resolved at this distance yet.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 512 PM CST Mon Nov 14 2022
VFR conditions will deteriorate to IFR by morning, as light snow
moves into southeast Iowa towards midnight. This will start first
at BRl and spread by 12Z to all other TAF sites. MVFR, occasional
IFR vis and cigs will continue through the day Tuesday, with light
east winds. Visibility will vary from 1 to 3 miles with light snow
and fog. Some wet snow accumulation is possible during the morning
hours on runways, and through the day on aircraft wing and
fuselage. Intensity of snow will be most significant in the
morning hours, with the fog component of the visibility most
significant during the afternoon and evening.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Winter Weather Advisory from 6 AM to 6 PM CST Tuesday for Benton-
Buchanan-Delaware-Dubuque-Jackson-Jones-Linn.
Winter Weather Advisory from 4 AM to 6 PM CST Tuesday for Cedar-
Clinton-Iowa-Johnson-Keokuk-Louisa-Muscatine-Scott-
Washington.
Winter Weather Advisory from midnight tonight to noon CST
Tuesday for Des Moines-Henry IA-Jefferson-Lee-Van Buren.
IL...Winter Weather Advisory from 6 AM to 6 PM CST Tuesday for
Carroll-Jo Daviess-Stephenson.
Winter Weather Advisory from 4 AM to 6 PM CST Tuesday for Bureau-
Henry IL-Mercer-Putnam-Rock Island-Whiteside.
Winter Weather Advisory from midnight tonight to noon CST
Tuesday for Hancock-Henderson-McDonough-Warren.
MO...Winter Weather Advisory from midnight tonight to noon CST
Tuesday for Clark-Scotland.
&&
$$
UPDATE...Ervin
SYNOPSIS...05
SHORT TERM...05
LONG TERM...05
AVIATION...Ervin
Area Forecast Discussion
National Weather Service Indianapolis IN
855 PM EST Mon Nov 14 2022
.Forecast Update...
Issued at 855 PM EST Mon Nov 14 2022
Latest high res numerical guidance has come in slightly warmer
overnight than forecast, and as a result have bumped min temps up a
bit. This has slight consequences for the late night/Tuesday
forecast with speeding the transition of snow to rain a bit, but
precipitation should be slowing by the time this transition occurs,
even with the slight speed up of the time frame, so amount forecasts
are roughly in line with previous forecast.
May be slightly too quick with the onset of pops as modest dry air
near the surface noted on ACARS soundings may require some top down
saturation before precip onset, but saw little to be gained by minor
tweaks of pops. Will leave as is for now.
&&
.Short Term...(This evening through Tuesday)
Issued at 313 PM EST Mon Nov 14 2022
* Light snow expected late tonight (southwest half) spreading
through much of central Indiana Tuesday morning.
* Accumulations up to around an inch are possible, especially
northwest.
* Potential mix with or change to rain will limit amounts south
* Uncertainty remains in how warm it will get and thus rain/snow
line as well as if any bands of of heavier snow would set up
Rest of this afternoon into this evening...
Cumulus field will slowly dissipate into the evening hours, but mid
and high clouds will be on the increase, making skies mostly cloudy
all areas by midnight. Temperatures will fall through the 30s.
Overnight into Tuesday morning...
An upper level trough will deepen some as it moves out of the
southern USA into Illinois. At the surface, an inverted trough will
nudge into the area, then a weak surface low will develop and move
into southern Indiana. The 850mb jet will remain focused in the
Tennessee Valley and points east.
Although the core of the low level jet will remain south and east of
the area, some warm advection and isentropic lift will still move
across the area overnight into Tuesday morning. The southerly flow
aloft will also bring in some moisture. Broad forcing from the upper
trough will boost the forcing. Thus, overall forcing will not be an
issue.
Initial precipitation will have to fight a dry layer in the mid
levels before it reaches the ground. Given this, will keep PoPs
lower for the first part of the overnight. As the atmosphere
moistens up and forcing continues, will increase PoPs to likely in
the far southwest by 12Z with lower PoPs to the north and east.
After 12Z will bring PoPs to likely or higher most areas as the
forcing from the upper trough continues.
Overnight temperatures will bottom out below freezing, but will be
not far from freezing in the far south. With cold temperatures
aloft, would expect snow as the precipitation type.
On Tuesday morning, boundary layer temperatures will warm slowly,
but precipitation should keep them in check. Without a decent
southerly flow, feel that the warmer models are too warm and will
trim back. With cold air remaining aloft, this will keep
precipitation type as snow across the northern half with rain mixing
in the south where the warmer air will be.
With the 850mb jet taking best moisture to the southeast, and with
the strongest forcing from the upper trough remaining to the west,
snowfall amounts should remain an inch or less.
Some uncertainty remains though on if warmer air will make it
farther north, which would limit amounts. On the other hand, there
will be a period with some frontogenetical forcing during the
morning, which could briefly enhance snowfall rates, mainly
northwest. These will have to watched as the event unfolds.
The snow will have the potential to impact the morning rush hour,
especially from Indy south and west.
Tuesday afternoon...
Precipitation will taper off in the south during the afternoon as
forcing moves north. Will lower or end PoPs there. Will keep chance
PoPs going north though as some forcing from the upper trough and
weak surface low continues. With temperatures continuing to warm,
rain will mix in farther north and lessen any lingering snow
accumulations. Highs will top out in the upper 30s north to around
40 south.
&&
.Long Term...(Tuesday night through Monday)
Issued at 313 PM EST Mon Nov 14 2022
* Light snow expected Tuesday night-Wednesday night
* Additional accumulations of 0.5-1" expected
* Well below normal temperatures through the 7-day forecast
A few lingering snow showers will potentially linger into Tuesday
overnight as the low exits to the east. Another upper wave will
quickly move in behind this system Wednesday with the potential for
more light snow showers during the afternoon to early overnight
timeframe. An additional 0.5-1" inch of snow is possible for the
beginning of the long term period. Locally higher amounts cannot be
ruled out across the northern half of the CWA where repeated snow
showers could occur. The upper wave will exit the region by daybreak
Thursday with mostly dry conditions expected immediately in the
wake. Yet another wave looks to move through for the end of the
week so have included lower PoPs at least for the latter half of
the day Thursday. The remainder of the period is expected to be
dry.
The cold airmass will remain over the Ohio Valley with broad
troughing aloft and NW flow. The multiple waves moving through the
region will reinforce the cold airmass, as temperatures trend colder
through at least Friday when highs are forecasted to be in the mid
to upper 20s and overnight lows drop into the teens. While still
below normal, highs will warm slightly, back into the 30s, this
weekend with more SW surface flow returning.
&&
.Aviation...(00Z TAF Issuance)
Issued at 603 PM EST Mon Nov 14 2022
Impacts:
* Light snow arriving around 10-12Z.
* Conditions deteriorating to IFR in precipitation on Tuesday.
Discussion:
Easterly winds with high clouds gradually lowering through the night
can be expected across the area. The next system arrives late
tonight into Tuesday morning with light snow overspreading the area
as early as about 10Z. Visibilities and ceilings will rapidly
deteriorate after snow onset through MVFR to IFR.
Restricted conditions will continue through the remainder of the
period, although some improvement to MVFR appears likely late in the
period.
Snow may turn to a rain/snow mix or all rain at BMG and perhaps HUF
as the day wears on Tuesday.
Winds will be below 10KT through the period, easterly at first,
becoming more variable or westerly very late in the period.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Update...Nield
Short Term...50
Long Term...KH
Aviation...Nield