Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/29/19

Area Forecast Discussion

National Weather Service Gaylord MI

 1039 PM EST Sat Dec 28 2019

.UPDATE...
Issued at 939 PM EST Sat Dec 28 2019

Initial area of warm air advection driven light precipitation
rotating slowly north across the Tip of the Mitt and southern
eastern upper Michigan this evening. This precipitation is
falling as a mixture of light rain/snow. Low level environment is
much drier further south, keeping much of the area south of M-68
dry. That will eventually change as we head through later tonight
into Sunday morning as corridor of extremely impressive moisture
rotates northeast into the region. Low level thermal profiles
keep this primarily rain across northern lower, with a freezing
rain/snow mixture across eastern upper. Still looking like some
light ice accumulation by morning, with heavier ice amounts during
the morning hours of Sunday.

&&

.NEAR TERM...(Through Tonight)
Issued at 320 PM EST Sat Dec 28 2019

...Freezing rain potential in Eastern Upper late tonight...

High Impact Weather Potential...Freezing rain potential in Eastern
Upper

Pattern Synopsis and Forecast:

Ridging persists along the west coast with deep troughing along the
Rockies. This troughing forms into a cut-off low and swings up
through Nebraska toward the upper Great Lakes overnight. Shortwave
ridging which gave us some decent clearing this morning is
continuing to push east this afternoon. Mid level moisture is slowly
undercutting it from the southwest. Mid and upper level clouds have
increased through the day, but profiles are likely still very dry in
the low levels over nrn Michigan...radar returns crossing mid
Michigan through the day haven`t been reaching the ground...with
little more than haze and mist reported in surface obs. The 1003mb
surface low is currently in Kansas, with its warm front extending
through KS/MO into the Ohio Valley. Warm air advection is well
underway across much of the midwest with widespread fog, rain and
freezing rain. A broad area of precipitation, aided by impressive
dynamics ahead of the wave, will continue to move northeast toward
the Upper Great Lakes through the evening. Radar coverage is trying
to slowly fill in over southern Wisconsin. But surface obs in this
area are reporting drizzle and ice needles.

Heading into the evening and overnight rain chances slowly
increases as moisture and great forcing ahead of the wave
overspread the area. Saw no reason to deviate much from inherited
pops overnight given uncertainty in low level saturation timing.
Guidance tries to push above- freezing air over ern upper below
the 900mb level before midnight, but wet bulb cooling should take
over once precipitation starts. The low level jet doesn`t look to
get into the region until closer to 4 or 5 am. This may impact how
quickly and how much warm air remains in the area after
saturation. To further add to the forecast icing uncertainty: both
the RAP and the NAM struggles to keep the low saturated, possibly
due to cold/dry easterly flow out of Ontario.

Overall think icing amount through daybreak is somewhat diminished,
but still a threat.

&&

.SHORT TERM...(Sunday through Tuesday)
Issued at 320 PM EST Sat Dec 28 2019

...Above normal temps with widespread precip and windy conditions...

High Impact Weather Potential...Widespread rain for all of Northern
Michigan...with freezing rain into Sunday morning across Eastern
Upper Michigan. Heavy rain is possible...especially late Sunday
night into Monday. Windy conditions will likely lead to lakeshore
flooding. Turning colder Monday night into Tuesday with some
accumulating snow possible.

Pattern Synopsis/Forecast...Deepening low center will reach Southern
Minnesota by 12Z Sunday and then hold over that general area thru
Sunday night. A second low will develop along the associated cold
front and lift northward...eventually merging with the Minnesota low
right over Northern Lake Michigan by Monday morning. This low will
actually retrograde back thru Lake Superior Monday afternoon...
Monday night and Tuesday.

Several waves of precip will impact our region Sunday thru Tuesday.
Widespread rain showers will continue to fall across our entire CWA
on Sunday...some of which will fall as freezing rain across Eastern
Upper Michigan Sunday morning. Winter Wx Advisory extends into
Sunday afternoon...but appears that most of the freezing rain
potential will be during the morning before surface temps begin to
warm to and just above freezing toward midday and into early
afternoon. Will certainly keep the Winter Wx Advisory for Eastern
Upper Michigan in tact with the expectation of up to a tenth of an
inch of additional ice accumulation possible during Sunday morning.
Precip should switch over to all rain across Eastern Upper Michigan
for several hours Sunday afternoon before additional chances of
freezing rain rears its ugly head again Sunday night as surface
temps drop to around the freezing mark with sunset. Will certainly
need to keep an eye on this potential return of freezing rain during
busy holiday travel.

Precip type across Northern Lower Michigan will remain all liquid
all day Sunday and thru Sunday night as strong WAA persists ahead of
the stalled low. There is also a slight chance of thunder across
Northern Lower Michigan on Sunday thanks to a narrow axis of weak
instability and enhanced 850 mb theta E along and ahead of the
associated warm front as it lifts thru our region. The potential for
heavy rain will be greatest late Sunday night into Monday morning as
the previously mentioned secondary low lifts northward toward
Michigan...merges with the upstream low and further deepens right
over our CWA by 12Z Monday. Deep moisture and strong low level
convergence will produce widespread rainfall with periods of
embedded heavy rainfall possible. Have issued an ESF to discuss this
potential...and will need to further evaluate the heavy rain/
flooding potential as this event draw closer. Also...lakeshore
flooding may become an issue Sunday into Monday as gale force winds
develop on the Lakes.

Temps will remain above normal thru Sunday...with high temps ranging
from the mid 30s across Eastern Upper Michigan to the mid to upper
40s across our SW and southern counties. Overnight lows will cool
mainly into the 30s. Things begin to change on Monday as CAA kicks
in from west to east across our CWA...dropping our temps and
gradually mixing some snow in with the ongoing rain. Precip type
should change over to all snow Monday night into Tuesday as CAA
begins to get the lakes involved...with some accumulation expected
especially across NW Lower Michigan. Low temps Monday night will
fall mainly in to the mid to upper 20s. High temps on Tuesday will
only warm a few degrees into the low to mid 30s.

.LONG TERM...(Tuesday night through Saturday)
Issued at 320 PM EST Sat Dec 28 2019

High Impact Weather Potential...Minimal. Generally small chances of
rain and snow into the weekend.

Pattern Synopsis/Forecast...Some light W/NW flow lake effect snow
showers will continue into Tuesday night. Surface ridge axis will
build into Michigan on Wednesday and slide east of our state by
Wednesday night. Two surface lows will approach the Great Lakes
Wednesday night thru Thursday night. One northern stream low will
slide eastward thru Canada and the other will lift NE thru the Ohio
Valley to the Mid Atlantic seaboard. Neither system will take direct
aim at our state...with Michigan positioned between any significant
lift or moisture from each. However...cannot rule out small chances
of precip across our CWA. Temps will rebound a bit during the end of
the week with high temps warming above freezing for most of our area
Thursday...Friday and Saturday.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 600 PM EST Sat Dec 28 2019

Deep low pressure will lift out of the Southern Plains and into
the Upper Mississippi Valley thru Sunday night. Deep moisture and
warm air will continue to surge northward ahead of this system and
into the Western Great Lakes region...producing widespread showers
across all of Northern Lower Michigan tonight into Sunday night.
There is also a slight chance of thunderstorms on Sunday...but the
chance is too small to include in the TAF for now. Conditions will
gradually deteriorate to MVFR and eventually IFR as this
widespread precip develops. LLWS will impact all of our TAF sites
late tonight thru Sunday morning. E/SE surface winds AOB 10 kts
this evening will strengthen overnight and Sunday...with gusts to
20 to 30 kts expected on Sunday.


&&

.MARINE...
Issued at 320 PM EST Sat Dec 28 2019

Winds will turn out of the southeast this evening as a strong low
pressure system approaches the area. Strength increases overnight in
response to the strengthening pressure gradient. Strong winds with
frequent gusts into gale force territory will be likely through the
day Sunday and into Monday morning. This incoming storm system will
also produce widespread moderate rainfall across the entire area.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER WEATHER ADVISORY until 4 PM EST Sunday for MIZ086>088-095-
     096.
LH...GALE WATCH from 6 AM EST Sunday through Monday morning for
     LHZ345>348.
     SMALL CRAFT ADVISORY until 4 PM EST Sunday for LHZ349.
LM...GALE WATCH from 6 AM EST Sunday through Monday morning for
     LMZ341-342.
     SMALL CRAFT ADVISORY until 4 PM EST Sunday for LMZ323-344>346.
LS...GALE WATCH from 6 AM EST Sunday through Monday morning for
     LSZ321-322.
&&

$$

UPDATE...MB
NEAR TERM...STJ
SHORT TERM...MR
LONG TERM...MR
AVIATION...MR
MARINE...STJ




Area Forecast Discussion

National Weather Service Quad Cities IA IL

 744 PM CST Sat Dec 28 2019

.UPDATE...
Issued at 737 PM CST Sat Dec 28 2019

The forecast is pretty well in hand for such a wild event. Rains
are rapidly lifting north, but have been slow to push east (which
makes sense in a negatively tilted upper low). That slow
progression has ended the fog quickly west where continuous light
to moderate rain is taking place, and in the northeast 1/3, to
improvement has occurred yet in dry/drizzle through 730 PM.
However, THAT`S GOING TO CHANGE BY 8 PM. Radar shows an eastward
extent to the WAA rains coming up from the south, and that should
effectively end our dense fog event. Rains thus far have followed
our QPF forecast, of highest totals in the far west. The HRRR
continues to show that this will hold trough 9 PM, then shift east
with the heavier/hr rates. Other than walking out the Fog advisory
counties, and tweaking the qpf and pops, the forecast appears in
good shape tonight and no major updates expected.

&&

.SYNOPSIS...
Issued at 327 PM CST Sat Dec 28 2019

The latest sfc analysis was indicating a quasi-stationary frontal
boundary acrs central KS and MO, with main low rolling northeast out
of the OK panhandle ATTM. Brisk southeast sfc winds and moisture
advection fueling areas of fog/some dense to the north of the
boundary, with fog headlines having to be issued and expanded
earlier today. Stout 40-50+ KT southerly LLVL flow to lee of large
Rockies upper trof complex conveyor-ing ample moisture up off the
western gulf, indicated by precipital water feed of 1+ inches up
toward the region. 12 hour highs will occur right before 6 PM, with
the Hwy 20 corridor barely getting around 40 by then while the far
south makes it into at least the lower 50s.

&&

.SHORT TERM...(This Evening through Sunday)
ISSUED AT 327 PM CST Sat Dec 28 2019

Tonight...A wet, increasingly mild night looks to be in store as a
large area of showers and even some embedded thunder make their way
up acrs the area tonight in the above described unseasonable warm
moist conveyor. Areas of fog, drizzle, lighter rain to be replaced
by this incoming activity, although any let up in the rain will
foster more fog development even with southeasterly sfc winds of 10-
20 KTs overnight. Will let ongoing fog headlines ride with
redevelopment, darkness settling in, and fog variability in mind, and
there still may be a need to expand northward if the dense banks
grow before the widespread rains make it up to the northern CWA. As
for more rain, the PWAT`s of an inch or more, conveyor orientation
to the incoming showers with some thunder, and forcing to lee of
large upper trof all suggest another round of unseasonable rainfall
of up to an inch to occur by 12z Sunday morning. Fortunately the
heavier rain axis appears to be setting up to stream acrs mainly
along and west of the MS RVR, avoiding an overlap from this
morning`s heavier rains of 0.40 to over three quarters of an inch
along and east of the MS RVR. But still expect some ponding of water
and rising creeks in areas that get the heavy rain axis tonight west
of the MS RVR, and there will be some passing bands of moderate to
locally heavy bouts of rain to the east also possibly producing some
urban and small stream nuisance flooding overnight into early
Sunday morning in areas that already have received over half an inch
of rain earlier today. In-sweeping dry slot with breezy south to
southwest winds to scour out the rains to the north and east after 3
to 4 AM or so. This feature also to erode any lingering fog from
south-to-north by Sunday morning.

A stronger embedded thunderstorm tonight may be able to produce some
pea size hail, as well as enhanced localized rainfall swaths, but
better instability for severe storms remains to the south acrs the
southeastern plains into central MO. Will bank on marginal lapse
rates and strong layering/inversion aloft to prevent a wet mix down
of brisk 50+ KT southwest winds aloft.

Non-diurnal temp trends continue tonight as warm front pulls up
through the CWA by 06z to 08z or so. Temps to warm into the low to
mid 50s almost CWA-wide, with a few mid to upper 50s possible in the
south and east. Some worry that with the conveyor of showers the
models are a bit quick with northward retreat of the warm front, but
still expect a warm surge toward Sunday morning even with a slowed
progression.

Sunday...A breezy unseasonably mild dry slot day, until continued
LLVL moisture feed interacts with convergent trof spiraling in
from the southwest off occluding cyclone rolling into southwestern
MN possibly produces some banded/linear light showers or rain in
spots later in the afternoon. Expect breezy southwest sfc winds of
15 to 25 MPH at times until they decrease by late afternoon. With
temps well up in the 50s at the the start of the period, mixing dry
slot air/winds could zoom morning highs in the upper 50s to around
60 along and east of the river, before the warm sector wedge gets
shunted off to the east. Will add a climate section as a few climate
sites not all that far off of record highs for the 29th, and Dubuque
having the best chance of making it.

.LONG TERM...(Sunday Night through Saturday)
ISSUED AT 327 PM CST Sat Dec 28 2019

Key Messages:

1. Another round of rain/showers looks to brush the eastern CWA
Sunday evening.

2. Increasing potential for light snow early in the week attendant
to a slow moving closed low.

3. Temperatures look to moderate modestly above normal mid to late
week, with low confidence system and precipitation chances late
week.

Sunday night:

Another burgeoning shield of precipitation is expected to brush
our eastern CWA Sunday night, as a vort max rotating through the
base of a deep upper trough lifts into the Great Lakes with
additional ascent provided from divergence in left exit region of
cyclonically curved upper jet. Thermal parameters support all rain
on the precipitation type. The rain should diminish early
overnight as the lift departs. Attention then turns to slow moving
upper low to our west. As it approaches expect to see the dry slot
fill in with very light precipitation overnight Sunday night,
especially across our western counties. Cooling temperatures aloft
will result in precipitation mixing or changing to snow, with only
minor accumulation possible and mostly on grassy or elevated
surfaces.

Monday and Monday night:

Will keep trends from overnight Sunday going for much of Monday,
with a continued filling of dry slot with very light precipitation
on Monday with approaching closed low. Continued cold advection on
gusty westerly winds will result in a mix of rain/snow going to
snow. Temperatures likely won`t rebound much on Monday but more
than a few degrees, with readings mostly in the lower to middle
30s by afternoon. Little, if any, accumulation is expected on
Monday and would be mostly confined to grassy or elevated surfaces
should it occur. Monday night there is growing signal for
accumulating light snow, as model consensus grows toward a
stronger vort max rotating down the backside of the Great Lakes
closed low into the region accompanied by a reinforcing cold front.
ECMWF is most aggressive with strength and subsequently a bit
wetter than other models advertising 0.1 to 0.2 inch, and so will
need to monitor as in general a little uptick noted in qpf albeit
still light. But if stronger trends persist then we could see potential
for an inch or two of accumulation Monday night especially from
around Quad Cities north/east. And brisk winds leading to colder
air with lows in the 20s Monday night and chills mostly in the teens
by daybreak.

Tuesday and Tuesday night:
Any lingering light snow should end by early in the day. In the wake,
a chilly and brisk New Years Eve day with highs mostly around 30 or
in the lower 30s. Good news is that it looks tranquil to end 2019 and
for any travel or festivities, as high pressure builds in. It will be
cold with lows overnight in the upper teens to mid 20s.

Wednesday through Saturday:

First few days of 2020 look to see moderating temperatures modestly
above normal by some 10-15 degrees with widespread highs in the
40s, as split flow pattern develops. Considerable uncertainty exists
in this pattern with phasing potential of both northern and southern
streams. Consensus with 12z model suite is phasing generally occurring
to our south/east late week, albeit though with some westward shift
in some of the medium range guidance, thus the late week period does
bear watching and for now contains the only precipitation chances in
this period.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
ISSUED AT 532 PM CST Sat Dec 28 2019

Very poor flying weather will continue tonight and Sunday, as a
wet winter storm system moves through the area. Widespread rain,
dense fog, low cigs, and low level wind shear winds will bring
dangerous challenges to anyone flying overnight. By morning, some
improvement to MVFR is possible as a dry slot of air wraps into
the low pressure system. Winds will shift from east tonight to
south Sunday. No freezing rain is expected in eastern Iowa or
Illinois.


&&

.HYDROLOGY...
Issued at 1125 AM CST Sat Dec 28 2019

Unseasonably heavy rain event for December underway, with first slug
of rain having deposited amounts of 0.3 to 0.8 inch over portions of
east central and southeast Iowa, northeast Missouri and northwest
Illinois. As a result, seeing some response in tributary rivers with
rises beginning on portions of the lower Rock, lower Wapsipinicon,
Skunk, La Moine, and lower Iowa basins. Another wave of moderate to
heavy rain organizing in the Plains will lift up across the area
tonight, and likely deposit another 0.5 to 1 inch across the Hydrologic
Service Area. The break, or period of mainly lighter rain/drizzle,
in-between these two slugs of heavier rain combined with an unfrozen
soil should allow for some infiltration. Thus, while this second round
of rain will likely bring additional rises on area tributary rivers
they should be predominantly within bank, but could come close to
flood stage at a few locations. The sites to watch for potentially
nearing flood stage currently are the Iowa River at Marengo,
Pecatonica River at Freeport, and English River at Kalona. This is
largely due to anticipation of additional heaviest rains falling
in portions of these basins with forecasts having input additional
rainfall over 1 to nearly 1.5 inches over the next 48 hours beginning
12z today. In addition, the input from some of the tributary rivers
will likely lead to rises on the lower portions of the Mississippi
River next week, with Burlington and Gladstone possibly coming close
to flood stage.

These rises on the tributaries and the lower Mississippi River will be
based on just how much additional rain occurs, and where the axis
of heaviest occurs over the next 48 hours. Confidence on extent
or magnitude of rises on area rivers is low given unfrozen soils
allowing for some infiltration, but will be monitored closely given
unseasonably high basin average rainfall around 1 to 1.5 inches being
forecast for this time of year.

&&

.CLIMATE...
ISSUED AT 327 PM CST Sat Dec 28 2019

Record Highs for December 29...

Moline.........65 in 1984
Cedar Rapids...60 in 1984
Dubuque........52 in 1984
Burlington.....65 in 1984

&&

.DVN WATCHES/WARNINGS/ADVISORIES...
IA...Dense Fog Advisory until midnight CST tonight for Clinton-
     Dubuque-Jackson-Scott.

IL...Dense Fog Advisory until midnight CST tonight for Bureau-Carroll-
     Henry IL-Jo Daviess-Mercer-Putnam-Rock Island-Stephenson-
     Whiteside.

MO...NONE.
&&

$$

UPDATE...Ervin
SYNOPSIS...12
SHORT TERM...12
LONG TERM...McClure
AVIATION...Ervin
HYDROLOGY...McClure
CLIMATE...12




Area Forecast Discussion

National Weather Service North Platte NE

 538 PM CST Sat Dec 28 2019

.SHORT TERM...(This evening through Sunday night)
Issued at 313 PM CST Sat Dec 28 2019

There are a few main concerns in the short term period.
First concern is with the pops for the rest of today/evening and
into Sunday. Adjusted the pops lower, especially through this
afternoon across southwest Nebraska and increased pops across
northern and north central Nebraska. The increase in pops is due to
convective type showers that have continued to develop all day
across north central and northern Nebraska. Decided to trend
towards consshort model as this seemed to have a better handle on
the convective showers across north central Nebraska. Across
southwest Nebraska drier air has inhibited much precipitation this
morning and early afternoon and the trend looks to continue the
rest of the afternoon and early evening, however snowfall is
expected to fill in across southwest Nebraska later this evening
but some uncertainty remains in just how much snowfall will occur
across southwest Nebraska.

Forecaster confidence is moderate in snowfall amounts across
north central and northern Nebraska where confidence is greater in
the amount of available moisture along with changeover timing to
snow. Confidence is lower across southwest Nebraska as there a
several uncertainties that could attribute to snowfall amounts but
decided to trend toward lower amounts based on the lack of
moisture seen this morning and early afternoon along with
temperatures remaining warmer all morning until presently.

The next concern in the short term period is the intensity of the
surface winds. Looking at bufkit soundings from the NAM, RAP, HRRR
and SREF there are strong winds in the sfc to 800 mb layer with the
most recent HRRR having the highest wind speeds at 60+kts between
900 and 800 mb layer for Sunday night. After collaboration with
surrounding offices agreement was made to increase wind speeds for
tonight through Sunday, with the increase of wind gusts up to 45
mph and approaching 50 mph in some locations. Also to note, wind
chills will hover near to slightly below zero for Sunday night
into Monday.

.LONG TERM...(Monday through Saturday)
Issued at 313 PM CST Sat Dec 28 2019

The main concern in the long term will be Monday winds. Confidence
in increasing in higher wind speeds for Monday morning into the
afternoon. An increase in wind speeds on Monday with wind gust of
40 to 45 mph possible. There is concern that with the increase in
winds on Monday that blowing snow could remain in issue,
especially for north central and portions of central Nebraska,
additional headlines may be needed for Monday and will continue to
monitor. Wind chills on Monday night will dip into the single
digits.

Temperatures remain mostly in the 30s and 40s through the rest of
the forecast period. The forecast appears mainly dry through
Saturday with only minimal chances for precipitation.

&&

.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 537 PM CST Sat Dec 28 2019

A wintry mix will slowly change over to all snow tonight. Snow will
lead to reductions in visibility down to a mile at times in heavier
snow bands. Gusty northwest winds are also a concern through Sunday
night as strong winds could cause blowing and drifting snow.


&&

.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Storm Warning until 6 PM CST /5 PM MST/ Sunday for
NEZ004>010-022>029-035>038-056>059-069>071-094.

&&

$$

SHORT TERM...Gomez
LONG TERM...Gomez
AVIATION...Kulik




lift, as mentioned in our previous short range forecast discussion.



 &&

.Short Term...(Tonight through Sunday evening)
Updated at 315 PM EST Sat Dec 28 2019

SFC boundary draped along the Ohio River will continue to push
northward as a warm front this afternoon and overnight in response
to the developing SFC low strengthening over the central Plains this
afternoon. Initially this evening, outside of a few sprinkles or
scattered light rain showers, we will be mostly dry and overcast
through the evening. Overnight, as a strong LLJ moves over the
region, our PoPs increase with more widespread rain showers moving
into the area during the predawn hours. It will also remain very
mild for this time of year with lows in the mid to upper 50s.

Very warm and moisture laden airmass will continue to be in place
for Sunday. The first wave of rain diminishes some before midday
before the second wave of heavier rain arrives in the afternoon into
the evening with PWAT values reaching 1.4 to 1.6 inch range. With
the heavy rain there is a chance of isolated embedded thunderstorms.
SPC has the southern half of our CWA in a Marginal Risk. Total QPF
from this event continues to be between 1.00 to 3.00 inches.
Collaborating with our neighbors a Flood Watch has been issued for
all our CWA. Could have some minor flooding during the event along
with some river flooding later next week in the Kentucky, Salt,
Rough, and especially Green River basins.

Temperatures remain unseasonably warm as highs Sunday, even with the
clouds and rain, could approach the middle to upper 60s. These highs
are just a few degrees below record highs for SDF, BWG & LEX.

&&

.Long Term...(After midnight Sunday night through Saturday)
Issued at 310 PM EST Sat Dec 28 2019

Sunday Night through Tuesday Night...

Surface cold front is forecast to be moving through the region at
the beginning of the forecast period.  Widespread moderate to
occasionally heavy rainfall will be in progress Sunday night.
Heaviest axis of precipitation Sunday night looks to favor our
eastern areas before tapering off Monday morning.  Sunday evening
temperatures will likely be in the upper 50s to the lower 60s, but
we`ll see temps fall steadily behind the front with readings falling
into the lower-mid 40s by Monday morning.

Decent dry slotting should cut into the region on Monday leaving
much of the day dry, cool, and windy. Highs will likely only top out
in the upper 40s to around 50 with lows in the lower 30s.  Winds of
10-20 MPH with gusts to 30 MPH at times will be possible. A
northwest flow will be seen Monday night with a slot of lower-level
moisture pivoting in from the northwest during the day on Tuesday. A
decent swath of light snow and/or flurries will be seen primarily
across northern/central IL/IN and Ohio, with some snow flurries
affecting portions of SE Indiana and some of our northern counties
in the Bluegrass.  Highs Tuesday will range from about 40 in
southern Indiana and northern Kentucky to the lower-mid 40s over far
southern KY.  Lows Tuesday night and ringing in 2020 will be in the
upper 20s.

Wednesday through Saturday...

Closed upper low over the eastern Great Lakes will slowly pivot
through New England as we head into the mid-week time frame.  Late
Wednesday we`ll see a developing trough axis out across the western
US with this trough digging a bit as it comes across the central
Plains by late week.  Strong S/SW flow out ahead of this trough will
bring another surge of milder temps and moisture back into the
region for Thursday/Friday and possibly into Saturday.

There remains some differences in the track of that system.
Yesterday`s and today`s Euro runs are still suggestive of a
stronger, more westward tracking system that would bring another
bout of heavy rainfall to the region.  The CMC and GFS solutions are
a little more progressive and a bit further to the east.  Using an
ensemble approach here of all three models will keep good continuity
within the ongoing forecast; which would still feature a high chance
of rainfall from Thursday afternoon through Friday night.

Highs Wednesday will range from the lower-mid 40s over southern IN
and northern KY to the upper 40s to around 50 down near the KY/TN
border region.  Warmer temps are expected for Thursday-Saturday with
highs in the low-mid 50s with overnight lows in the upper 30s to the
lower 40s.

&&

.Aviation...(00Z TAF Issuance)
Issued at 645 PM EST Sat Dec 28 2019

All TAF sites currently are VFR with an east-southeast surface wind
of 5-10 kts. NWS Doppler radar shows scattered showers affecting BWG
at this time, and they will affect SDF by 01 UTC. With a storm
system to our west, rainfall coverage will increase late tonight/
overnight as surface winds begin to increase from the southeast,
eventually becoming southerly by or before 12 UTC at most sites with
gusts near 20 kts. Ceilings and vsbys will become MVFR overnight
with IFR ceilings possible at HNB starting roughly around 09 UTC.

On Sunday, a steady rain (moderate-heavy at times) will occur across
a good portion of central KY and south-central IN, including all TAF
sites, with an embedded thunderstorm possible. Ceilings should
generally be IFR but be low MVFR at times, with generally MVFR
vsbys. Surface winds will continue gusty from the south at 20-25
kts. Models suggest rain and associated lower ceilings may improve
temporarily at HNB Sunday afternoon before another surge of moisture
affects the region late Sunday and during the evening. Surface winds
should start to veer to the southwest and diminish to about 10 kts
near the end of the forecast period at most TAF sites.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...Flood Watch through Sunday evening for INZ076>079-083-084-
     089>092.

KY...Flood Watch through Sunday evening for KYZ023>043-045>049-
     053>057-061>067-070>078-081-082.

&&

$$

Update...TWF
Short Term...BTN
Long Term...MJ
Aviation...TWF



Area Forecast Discussion

National Weather Service Nashville TN

 717 PM CST Sat Dec 28 2019

.UPDATE...
FOR EVENING DISCUSSION.

&&

.DISCUSSION...

Current radar imagery is showing a lull in shower activity early
this evening, and the latest HRRR suggests only scattered cells
until closer to 12Z tomorrow morning when showers will increase
from the west as a cold front nears the mid state. At this time,
a deep surface low is centered over eastern KS, but this system
will race eastward during the next 24 hours. The 00Z sounding from
OHX shows a stable atmosphere still in place (zero CAPE, +4
lifted index). But the precipitable water has increased to 1.20
inches, which puts us well above the 90th percentile
climatologically for this time of year. In addition, 850 mb winds
have increase to 30 kts, and low-level winds will continue to
increase during the next several hours. So both the moisture and
moisture transport are becoming established. Overnight QPF is
relatively low. The heaviest rain won`t really set in until after
18Z tomorrow. Current grids are holding up well thus far. Don`t
anticipate much of a change to the forecast this shift.

&&

.AVIATION...
00Z TAF DISCUSSION.

BNA/MQY/CKV/CSV...Scattered showers are moving northward across
Middle Tennessee late this afternoon but should not affect the
terminals. The latest HRRR shows surprisingly little activity
across the mid state this evening and overnight. The heavier
showers won`t settle in until tomorrow. So look for ceilings to
lower to MVFR after 06Z with mainly light showers. Am including
LLWS remarks at CKV/CSV owing to an increase in the LLJ later
tonight & tomorrow. LLWS criteria should be met at these two
terminals.


&&

.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

DISCUSSION......08
AVIATION........08