Special Weather Statement, NWS Memphis, TN

Area Forecast Discussion
National Weather Service Memphis TN
1156 AM CST Sat Dec 17 2016

.UPDATE...

Updated for aviation discussion below

&&

.PREV DISCUSSION... /issued 532 AM CST Sat Dec 17 2016/

UPDATE...

Updated for the 12Z Aviation Discussion

PREV DISCUSSION... /issued 508 AM CST Sat Dec 17 2016/

DISCUSSION...Surface analysis this morning places a warm front
across Southern Missouri and Southern Illinois while a trailing
cold front is located across Oklahoma and the Texas Panhandle.
KNQA WSR-88D shows a few light warm advection rain showers across
portions of West Tennessee near the Tennessee River and Northeast
Mississippi. As of 4 am CST, temperatures across the Mid-South
range from the upper 50s to middle 60s across most locations.

A tight pressure gradient across the Lower Mississippi Valley and
925 mb low level jet around 50 kts is producing breezy conditions
across the forecast area. These breezy conditions are expected to
persist through the day with winds remaining just below wind
advisory criteria. Thus, held off on issuing a Wind Advisory with
this issuance but will continue to monitor trends if short term
observation/forecast trends suggest otherwise.

The aforementioned cold front will begin to move across Arkansas
mainly this afternoon into tonight. Short term model soundings
indicate a low level capping inversion will be present until the
front arrives across the region. This should limit overall any
decent shower and thunderstorm activity to areas along the front
with any earlier precipitation being warm advection rain showers.
Surface based instability values between 500-1000 J/kg, 0-1 km
Storm Relative Helicity values between 250-300 m2/s2, 0-6 km Bulk
Shear Values between 60-70 kts, favorable winds aloft and backing
surface winds suggest convective mode may be in the form of a
quasi-linear convective system with a small potential for a brief
tornado to develop within bowing segments. At this time, think the
best potential for severe thunderstorms across the Mid-South will
be especially along and south of I-40 where better instability
will exist. The predominant threat will be damaging winds for any
thunderstorm that is able to attain severe limits.

An arctic airmass building in behind the front will result in
precipitation gradually transitioning to freezing rain or
freezing drizzle as the bulk of precipitation departs the Mid-
South. Some questions still remain on the amount of precipitation
that will be available as the cold arctic air spills into the
area. In addition, area soil temperatures remain above freezing
at many locations which should limit winter hazards to mainly
elevated surfaces such as overpasses. Thus, will continue with a
Special Weather Statement and hold off on a Winter Weather
Advisory for the time being. Winter weather headlines will be
reassessed once additional model data arrives later this morning
into early afternoon.

Temperatures are expected to fall into the teens Sunday night
across the forecast area. These cold temperatures combined with
a N/NNE wind are anticipated to produce wind chill readings at or
below zero for a period late Sunday night into Early Monday
Morning across the northern third of the area. Thus, a Wind Chill
Advisory may be needed during this time frame.

Long term model trends indicate precipitation chances will return
as another upper level trough and associated cold front will move
through the region Wednesday night with high pressure returning
for the start of next weekend. Temperatures in the long term
forecast are anticipated to average near normal for December.

CJC

&&

.AVIATION...
18Z TAF cycle

Winds, ceilings, weather all a problem this cycle. Strong and gusty
southerly winds to continue this afternoon. Winds will veer to
northwesterly and blustery early this evening. Rain and
thunderstorms could come in this afternoon and last into the
evening. Then freezing drizzle possible at Jonesboro and Memphis.
Ceilings to drop below 1000 feet after frontal passage.

WER

&&

.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Winter Weather Advisory from midnight tonight to 8 AM CST Sunday
     for Clay-Craighead-Crittenden-Greene-Lawrence-Mississippi-
     Poinsett-Randolph.

MO...Winter Weather Advisory from midnight tonight to 8 AM CST Sunday
     for Dunklin-Pemiscot.

MS...Winter Weather Advisory from midnight tonight to 8 AM CST Sunday
     for Alcorn-Benton MS-DeSoto-Marshall-Prentiss-Tippah-
     Tishomingo.

TN...Winter Weather Advisory from midnight tonight to 8 AM CST Sunday
     for Benton TN-Carroll-Chester-Crockett-Decatur-Dyer-Fayette-
     Gibson-Hardeman-Hardin-Haywood-Henderson-Henry-Lake-
     Lauderdale-Madison-McNairy-Obion-Shelby-Tipton-Weakley.

&&

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE MEMPHIS TN
159 PM CST SAT DEC 17 2016

ARZ008-009-017-018-026>028-035-036-048-049-058-MOZ113-115-
MSZ001>017-020>024-TNZ001>004-019>022-048>055-088>092-182200-
ALCORN-BENTON MS-BENTON TN-CALHOUN-CARROLL-CHESTER-CHICKASAW-CLAY-
COAHOMA-CRAIGHEAD-CRITTENDEN-CROCKETT-CROSS-DESOTO-DECATUR-
DUNKLIN-DYER-FAYETTE-GIBSON-GREENE-HARDEMAN-HARDIN-HAYWOOD-
HENDERSON-HENRY-ITAWAMBA-LAFAYETTE-LAKE-LAUDERDALE-LAWRENCE-
LEE AR-LEE MS-MADISON-MARSHALL-MCNAIRY-MISSISSIPPI-MONROE-OBION-
PANOLA-PEMISCOT-PHILLIPS-POINSETT-PONTOTOC-PRENTISS-QUITMAN-
RANDOLPH-SHELBY-ST. FRANCIS-TALLAHATCHIE-TATE-TIPPAH-TIPTON-
TISHOMINGO-TUNICA-UNION-WEAKLEY-YALOBUSHA-
159 PM CST SAT DEC 17 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST ARKANSAS...
THE MISSOURI BOOTHEEL...NORTH MISSISSIPPI...AND WEST TENNESSEE.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THERE IS A SLIGHT RISK FOR SEVERE THUNDERSTORMS OVER THE MIDSOUTH
THROUGH LATE THIS EVENING. DAMAGING WINDS WILL BE THE PRIMARY
SEVERE WEATHER THREAT. ONE OR TWO TORNADOES WILL ALSO BE POSSIBLE.
THE SEVERE WEATHER THREAT WILL GRADUALLY MOVE FROM NORTHEAST
ARKANSAS...THE MISSOURI BOOTHEEL AND NORTHWEST TENNESSEE THIS
AFTERNOON...TO NORTH MISSISSIPPI LATE THIS EVENING.

SIGNIFICANTLY COLDER AIR WILL ARRIVE TONIGHT...BEHIND AN ARCTIC
COLD FRONT. THERE MAY BE AN HOUR OR TWO WHERE SUBFREEZING TEMPERATURES
CHANGE THE GRADUALLY DIMINISHING LIGHT RAIN OVER TO LIGHT FREEZING
RAIN AND SLEET LATE THIS EVENING AND OVERNIGHT. ONLY MINOR
ACCUMULATIONS OF ICE ARE EXPECTED...BUT THIS MAY BE SUFFICIENT TO
CREATE SLICK SPOTS ON ELEVATED SURFACES AND BRIDGES. FOR
ADDITIONAL INFORMATION...SEE THE LATEST WINTER WEATHER ADVISORY.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

SUBFREEZING WIND CHILLS WILL BE POSSIBLE EARLY MONDAY MORNING
ALONG AND NORTH OF THE INTERSTATE 40 CORRIDOR...INCLUDING THE
MEMPHIS METRO AREA.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

PWB

Special Weather Statement
National Weather Service Memphis TN
204 PM CST SAT DEC 17 2016

ARZ009-018-MOZ113-172030-
Greene AR-Clay AR-Dunklin MO-
204 PM CST SAT DEC 17 2016

...THE NATIONAL WEATHER SERVICE IN Memphis HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY Until 230 PM CST FOR...

Eastern Greene County in eastern Arkansas...
Southeastern Clay County in eastern Arkansas...
Dunklin County in southeastern Missouri...

At 203 PM CST...a strong thunderstorm producing Pea size hail or
larger and winds at least 40 mph was located near Cardwell, or 7
miles south of Marmaduke.

Very heavy rain along with continuous cloud to ground lightning are
also possible with this thunderstorm.

People in eastern Greene...southeastern Clay and Dunklin Counties
should monitor this storm closely.

LAT...LON 3639 8996 3600 8997 3599 9048 3615 9047
TIME...MOT...LOC 2003Z 240DEG 49KT 3607 9036