000
ACUS01 KWNS 231619
SWODY1
SPC AC 231618

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
1018 AM CST Sat Feb 23 2019

Valid 231630Z - 241200Z

...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS NORTHERN
MS...SOUTHWEST TN...NORTHWEST AL...

...SUMMARY...
A few strong tornadoes, scattered damaging winds, and isolated large
hail are expected, primarily through this evening across the Lower
Mississippi Valley into the Tennessee Valley. The most dangerous
period for tornadoes should be around 2 to 8 PM CST across northern
Mississippi, southwest Tennessee, and far northwest Alabama.

...Lower MS and TN Valleys...
No change made to previous outlook except behind ongoing convection
in the Ark-La-Tex. Overall forecast scenario is anticipated to
unfold from midday through tonight.

A surface cyclone over far northwest OK will translate quickly
northeastward, reaching southern WI around midnight. The cyclone
will deepen rapidly in conjunction with an ejecting midlevel
shortwave trough and the left-exit region of a strengthening (100+
kt) mid-upper jet streak. The deepening cyclone will draw the moist
warm sector northward from the central Gulf Coast States into parts
of the Mid-South to perhaps as far north as the Lower OH Valley
later this afternoon/evening to the east of a cold front, as a 50-60
kt low-level jet shifts across the northern part of the warm sector.
Marginally severe hail could occur with the stronger elevated storms
across the mid MS Valley, but the primary severe threat is expected
farther to the south in the warm moist sector.

Ongoing convection across the Sabine Valley into southern AR will
increase in coverage/intensity as large-scale ascent overspreads the
northwest portion of the rich moist sector characterized by upper
60s to lower 70s boundary-layer dew points. The most robust
insolation appears to be underway downstream of this activity across
northern LA into central/northern MS where surface temperatures
should warm into the upper 70s. This will support afternoon MLCAPE
of 1000-2000 J/kg, with only weak convective inhibition.
Semi-discrete storms are expected within the lingering band of
ongoing convection, and in the open warm sector, given strong
deep-layer shear and substantial cross-boundary shear vectors. The
tornado threat will be greatest from about 20-02Z across
central/northern MS into northwest AL and southwest TN. A few strong
tornadoes appear probable given 0-1 km/effective SRH of 300-500
m2/s2 and effective bulk shear near 60 kt in the rich moist
environment. Thereafter, storms should weaken by 03-06Z, though
isolated tornado/damaging wind potential could persist into the
early morning across northeast AL/northwest GA where storms will
encounter a remnant wedge front.

..Grams/Wendt.. 02/23/2019

$$

000
ACUS02 KWNS 231711
SWODY2
SPC AC 231711

Day 2 Convective Outlook
NWS Storm Prediction Center Norman OK
1111 AM CST Sat Feb 23 2019

Valid 241200Z - 251200Z

...THERE IS A MARGINAL RISK OF SEVERE THUNDERSTORMS OVER A PORTION
OF CENTRAL AND SOUTHERN GEORGIA...

...SUMMARY...
A few storms with gusty winds might occur Sunday morning, mainly
across a portion of central and southern Georgia.

...Southeast States...

A strong synoptic upper trough will move northeast through the Ohio
Valley, Great Lakes and Northeast U.S. Sunday with attendant area of
low pressure occluding over the Great Lakes. Trailing front will
extend south from the low through the Southern Appalachians into the
western FL Panhandle. A moist boundary layer with mid 60s F
dewpoints will advect through the pre-frontal warm sector as far
north as central GA and the coastal Carolinas. However, instability
will remain very weak (MUCAPE less than 500 J/kg) owing to
widespread clouds and marginal lapse rates. A low topped band of
convection will likely accompany the cold front early in the period,
much of which will produce little to no lightning. This activity
will be embedded within strong wind fields with 40-50 kt in the
lowest 2 km, and potential will exist for some of this momentum to
be transported down to the surface. However, the tendency will be
for deeper forcing accompanying the upper trough to remain well
north of the warm sector which, in conjunction with the expected
very marginal thermodynamic environment, suggest any severe threat
will remain marginal at best.

...MAXIMUM RISK BY HAZARD...
Tornado:  <2%     - None
Wind:      5%     - Marginal
Hail:     <5%     - None

..Dial.. 02/23/2019

$$

000
NWUS53 KAPX 211313
LSRAPX

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GAYLORD MI
813 AM EST THU FEB 21 2019

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0800 AM     SNOW             2 E SAULT STE. MARIE    46.49N 84.32W
02/21/2019  M4.5 INCH        CHIPPEWA           MI   COCORAHS

            COCORAHS STATION MI-CP-14, 2 E SAULT STE.
            MARIE. THE DURATION OF THE SNOW EVENT WAS 24
            HOURS.

0700 AM     SNOW             1 SSE SAINT IGNACE      45.86N 84.72W
02/21/2019  M3.0 INCH        MACKINAC           MI   COCORAHS

            COCORAHS STATION MI-MC-4, SAINT IGNACE. THE
            DURATION OF THE SNOW EVENT WAS 24 HOURS.

0700 AM     SNOW             1 WSW IRONTON           45.26N 85.22W
02/21/2019  M3.0 INCH        CHARLEVOIX         MI   COCORAHS

            COCORAHS STATION MI-CX-4, IRONTON. THE
            DURATION OF THE SNOW EVENT WAS 24 HOURS.

0700 AM     SNOW             3 W OMENA               45.06N 85.65W
02/21/2019  M3.1 INCH        LEELANAU           MI   COCORAHS

            COCORAHS STATION MI-LL-1, 2 W OMENA. THE
            DURATION OF THE SNOW EVENT WAS 24 HOURS.


&&

$$

000
FXUS63 KAPX 231603
AFDAPX

Area Forecast Discussion
National Weather Service Gaylord MI
1103 AM EST Sat Feb 23 2019

.UPDATE...
Issued at 1102 AM EST Sat Feb 23 2019

12z surface/composite analysis shows Midwest/upper Great Lakes beneath
a broad zone of low/mid level warm advection between high pressure
over New England and low pressure organizing over the Texas/Oklahoma
panhandles ahead of short wave energy emerging out onto the
central/southern High Plains. Isentropic ascent and right entrance
jet forcing along with weaker stability supporting a fairly large
area of precipitation across eastern Iowa/Wisconsin/Upper
Michigan...with snow on the northern end and rain/freezing rain to
the south. Dry air lingers below 700mb per 12z APX/GRB/DTX
soundings...so precipitation having a harder time reaching the
ground over eastern Upper though getting some snow at SJX/ISQ/PLN.
Will continue to see periods of snow spread across eastern Upper...
while precipitation over Wisconsin gradually overspreads most of
northern Lower during the afternoon hours. Precipitation type will
be a concern as low level warm nose spreads into northern Lower...
while surface temperatures have been climbing but dew points in
the lower-mid 20s allows some room for wet-bulbing and temperatures
perhaps being knocked back a couple of degrees with precip onset.
Interior higher terrain areas are the biggest concern this
afternoon with temperatures likely flirting with the freezing
mark. Afternoon precip across northern Lower likely to be all
liquid by the time it arrives...so surface temperatures will be
key to icing potential.

Have not made any changes to tonight`s forecast yet...suspect we
may "drizzle out" for a time as mid level moisture strips away for
a period of time with another surge of precipitation later
tonight.

&&

.NEAR TERM...(Today through Tonight)
Issued at 300 AM EST Sat Feb 23 2019

High impact weather: Freezing rain and some light accumulations of
snow. Main area to be impacted: eastern upper Michigan.

Pattern synopsis and forecast:

A negatively tilted upper trough with and it`s associated area of
deepening low pressure was pressing into the srn Plains early this
morning. Deep Gulf of Mexico moisture was surging out ahead of this
storm system, and when combined with widespread WAA, pockets of DPVA
from energy ejected from the trough, and upper divergence/jet
dynamics from a double jet streak pattern, and several areas of
precipitation were impacting the eastern two-thirds of the country.
The closest batch to nrn Michigan resided out across the mid and
upper Mississippi valley, where some relatively weaker forcing was
resulting in some light snow in somewhat high based clouds, which
was trying to develop eastward into the western Great Lakes. Further
south into Missouri/Kansas, another batch of rain showers, as well
as some embedded thunderstorms, were tracking NE. The strongest
forcing was just ahead of the main upper trough and sfc low moving
into NW Texas and the Oklahoma panhandle.

The upper trough and sfc low will lift into the mid Mississippi
valley by this evening, and into the western Great Lakes through
tonight, while the associated sfc low will continue to rapidly
deepen. A few waves of precipitation are expected over this time.
The first is with that batch of light snow trying to develop into
the western Great Lakes. Although the air mass is not very saturated
below 8kft, forcing and top down saturation is expected to continue
to develop the band of snow that drifts into areas north of M-32 in
nrn lower, and especially into eastern upper this morning. Not too
big of a deal with a half inch to an inch for mainly eastern upper.

Then, more attention needs to be paid to the batch of precipitation
currently in MO/KS, which is expected to make it into nrn Michigan
late this afternoon and evening. We will be under increasing WAA all
the way through tonight, and this is when the concerns about
precipitation start. Fcst soundings continue to show a pronounced
warm layer aloft, melting precipitation aloft. Out ahead of this
warm layer, P-type is expected to fall as snow mainly in the nrn
CWA, and a snow/rain mix south, before changing to rain in most
areas of nrn lower by late afternoon and evening (sfc temperatures
rising into the mid and upper 30s). The problem has been, and
continues to be, can the increasing WAA stop any significant sfc
temperature drop in the evening? Was wondering about this yesterday
morning, and the latest data has trended that way, with most areas
of nrn lower in the 33F to 36F range, thus resulting in a decreased
threat to any significant freezing rain chance. On the other hand,
for eastern upper, sfc temperatures are expected to be in the lower
30s while the warm layer aloft arrives, leaving a more significant
freezing rain/sleet scenario. Ice amounts up to a quarter of an inch
are possible. Also, nrn Michigan lies on the nrn end of general
thunderstorms. There is some 200 j/kg or so of MUCAPE tonight for
the srn CWA, so don`t be surprised to hear a rumble of thunder.

Sfc temperatures continue to rise through the overnight hours, and
the next wave of forcing (strongest forcing), with the parent upper
trough and sfc low brings the heaviest precipitation. All rain is
expected in nrn lower, with even eastern sections of Chip/Mack
counties in eastern upper possibly changing over to primarily rain.
Mainly snows in western sections of the counties with 1-3" possible.
There is a fine line here on P-type, making headline decisions
difficult.

Will plan on going to a Winter Storm Warning for eastern upper due
to more confidence in getting the freezing precipitation tonight.
Will hold the watch for nrn lower for additional looks at
temperature data through today, which can maybe lead to more
confidence one way or another on freezing rain/rain (1-2 degrees
makes a huge difference). Finally, there`s the best confidence in no
freezing rain issue across some of the far SE counties, who are
likely to be removed from most of the upcoming snow/lake effect snow
for Sunday (see below). Am considering going to a high wind watch
due to potential very strong wind gusts (again see below).

&&

.SHORT TERM...(Sunday through Monday)
Issued at 255 AM EST Sat Feb 23 2019

High Impact Weather Potential: High

Primary Forecast Concerns/Challenges: Blowing/drifting snow with
very strong winds Sunday into Monday morning.

By Sunday morning the upper level low will be over nrn lake
Michigan, with its surface low getting stacked underneath. The main
occluded front pivots through E. Upper early in the morning, and our
warm nose gets shunted off to the north and east. Low level flow
picks up out of the southwest as the surface low moves through the
nrn portions of the lake. We quickly recover from the dry slot
Sunday morning, and profiles suggest a rain/snow mix with surface
temperatures still above freezing for N. Lower. Early in the
morning, some ponding on roadways is still possible, given some snow
melt and continued rain mixed in. Through the day cold air filtering
in behind the low will steadily drop surface temperatures. According
to ensembles, temperatures fall below freezing between 18 and 21z
for most places west of I-75 and north of M-55, allowing the
changeover to all snow Sunday afternoon. Further south and east, the
switchover to snow occurs a little later. Winds become a concern
starting in the early afternoon, then last through the night. The
low will surprisingly still be intensifying as it passes through
the Straits region, and the pressure gradient quickly tightens
over the area. Winds switch out of the northwest and becomes
sustained between 25 and 35 kts mid morning. Bufkit momentum
transfer readouts bring anywhere from 45 to 55 kts (or more)
easily down to the surface. With strong CAA/downward motion/mixed
boundary layer, these values seem likely. Potential for blowing
snow increases as SLR`s increase in the colder air. Widespread
reduced visibility and blowing/drifting snow are likely, with
possible whiteout conditions from Sunday afternoon through early
Monday morning. North-south orientated roads and any open areas
with be the hardest hit by whiteout conditions. Some potentially
heavy snow bands could set up from Sunday afternoon into the
overnight hours, as inversion heights rise to around 5 kft, delta-
Ts increase to near 15 C, a deep DGZ forming, strong
unidirectional BL winds, and plenty of low and mid- level moisture
leftover.

Sunday night temperatures continue to plummet through the teens,
bottoming out in the single digits in E.Upper and higher terrain of
N. Lower. The pressure gradient remains tight through the night into
Monday morning, although it slackens a bit, easing wind gusts down
into the 20s by mid-morning. Nevertheless, some blowing and drifting
snow is still definitely possible through the morning hours. We
transition to a pure lake effect regime Monday afternoon, with
slightly stronger overlake instability, but it will be fighting
sinking inversion heights down to near 3 kft. Winds also slowly back
through the day, spreading out accumulations. Highs do not rebound
very much, into the lower teens north and upper teens south.

.LONG TERM...(Monday night through Friday)
Issued at 255 AM EST Sat Feb 23 2019

High Impact Weather Potential: Low

Primary Forecast Concerns/Challenges: Minimal

Strong ridging in the eastern Pacific will extend north, pushing
large positive 500mb height anomolies well north of Alaska. This
will likely push waves of very cold air over our region, especially
next weekend. We`ll be under general troughing for much of next
week, with weak waves passing over the area, each bringing a chance
of snow. Surface high pressure slides in Tuesday, followed by a weak
system on Wednesday. Guidance is still fairly spread on the
Wednesday system however. The end of the week appears quiet for now,
until another potential system early next weekend. As mentioned
above temperatures will be cold, ranging about 10 or 15 degrees
below normal for late February.

&&

.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 618 AM EST Sat Feb 23 2019

Strong/deepening low pressure moving into the srn Plains will lift
up into nrn Michigan by daybreak Sunday. Outside of some possible
brief light snow at PLN through shortly after daybreak, VFR
conditions in thickening mid and upper level clouds will be common
through the day. Then, MVFR/IFR conditions return, in mixed
precipitation of rain, snow and some freezing rain, which will
spread over all of nrn Michigan later this afternoon and into
tonight. Precipitation is expected to change over to all rain
later tonight in a warming air mass.

Light ESE winds will increase later today and into tonight ahead of
the approaching storm, with mechanical mixing likely getting held
back due to a stable near sfc layer. This brings in the likely
development of LLWS, which continues through much of tonight.


&&

.APX WATCHES/WARNINGS/ADVISORIES...
MI...WINTER STORM WATCH from 4 PM EST this afternoon through Monday
morning for MIZ016>023-025>028-031>033.

WINTER STORM WATCH from 4 PM EST this afternoon through late
Sunday night for MIZ024-029-030-034>036-041-042.

WINTER STORM WARNING from 4 PM this afternoon to 7 AM EST Monday
for MIZ008-015.

&&

$$

UPDATE...JPB
NEAR TERM...SMD
SHORT TERM...STJ
LONG TERM...STJ
AVIATION...SMD

000
ACUS11 KWNS 231653
SWOMCD
SPC MCD 231652
MSZ000-ARZ000-LAZ000-231845-

Mesoscale Discussion 0124
NWS Storm Prediction Center Norman OK
1052 AM CST Sat Feb 23 2019

Areas affected...central and northern LA...southeast AR...central
and northern MS

Concerning...Severe potential...Tornado Watch likely

Valid 231652Z - 231845Z

Probability of Watch Issuance...95 percent

SUMMARY...A tornado watch will likely be needed between 12-1pm for
LA into portions of AR and MS.  One or two tornado watches will
likely be required by early afternoon over the lower MS Valley
region.

DISCUSSION...Radar mosaic shows a weak squall line developing over
northwest LA into southwestern AR.  The squall line is co-located
with the Pacific front/dryline over the Sabine Valley.  Visible
satellite imagery shows a broken cumulus field from northeast LA
through MS where surface heating is contributing to temperatures
rising into the lower to middle 70s degrees F.

The 9am Univ. Louisiana Monroe special Vortex2SE sounding showed a
residual capping inversion near 700mb.  The capping inversion has so
far impeded sustained, free warm sector convective development to
the east of the squall line.  The 14.1 g/kg lowest 100mb mean mixing
ratio indicative of a very moist airmass beneath 8.7 degree C/km
700-500mb lapse rates, are suggestive of moderate buoyancy
developing this afternoon as temperatures gradually warm through the
middle 70s.  Some slight cooling of mid-level temperatures
---reducing the effects of a warm layer noticed above 500mb in the
Monroe, LA sounding--- may occur during the next few hours and
further contribute to destabilization.

Strengthening mid-to high-level flow fields this afternoon will
promote storm organization with a favored tendency for supercells
with updrafts not located within a cold pool-forced ascent regime
(i.e., squall line).  As such, strong low-level shear will
potentially favor strong low-level mesocyclone rotation with the
more robust/discrete updrafts.  A couple of tornadoes, in addition
to damaging winds, are the primary hazards.

..Smith/Grams.. 02/23/2019

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...MEG...JAN...LIX...LZK...LCH...SHV...

LAT...LON   33179283 34359125 34499046 34238970 33538917 32638932
            30889133 30819245 31289328 32059344 33179283