Alert archive / Kentucky / Mesoscale Discussions in 2016

Mesoscale Discussion 40

January 21, 20164 states

The Storm Prediction Center issued this mesoscale discussion at Jan 21, 2016, 10:53 PM CST for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jan 21, 2016, 10:53 PM CST (04:53 UTC)
Expired
Jan 22, 2016, 4:00 AM CST
In force
5 hr
Issued by
the Storm Prediction Center
All 55 counties

Clay County, AR, Adair County, KY, Allen County, KY, Ballard County, KY, Barren County, KY, Butler County, KY, Caldwell County, KY, Calloway County, KY, Carlisle County, KY, Christian County, KY, Clinton County, KY, Cumberland County, KY, Edmonson County, KY, Fulton County, KY, Graves County, KY, Hickman County, KY, Logan County, KY, Lyon County, KY, Marshall County, KY, McCracken County, KY, McCreary County, KY, Metcalfe County, KY, Monroe County, KY, Muhlenberg County, KY, Russell County, KY, Simpson County, KY, Todd County, KY, Trigg County, KY, Warren County, KY, Wayne County, KY, Dunklin County, MO, Mississippi County, MO, New Madrid County, MO, Pemiscot County, MO, Benton County, TN, Carroll County, TN, Cheatham County, TN, Clay County, TN, Dyer County, TN, Gibson County, TN, Henry County, TN, Houston County, TN, Jackson County, TN, Lake County, TN, Lauderdale County, TN, Macon County, TN, Montgomery County, TN, Obion County, TN, Pickett County, TN, Robertson County, TN, Scott County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Weakley County, TN

The radar

The Ft Campbell radar (KHPX), 61 km from the middle of the area, began a volume at 04:54 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 00:00Z, 4.9 hours before the alert went out and 116 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Nashville Metro, TN at 00:00Z on 2016-01-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Nashville Metro, TN at 00:00Z on 2016-01-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 200 square meters per square second.1939587897117Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
716 m above ground
0-6 km bulk shear
45 kt
0-1 km storm-relative helicity
200 m²/s²
0-3 km storm-relative helicity
238 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

688 
ACUS11 KWNS 220453
SWOMCD
SPC MCD 220453 
KYZ000-TNZ000-ILZ000-MOZ000-ARZ000-221000-

MESOSCALE DISCUSSION 0040
NWS STORM PREDICTION CENTER NORMAN OK
1053 PM CST THU JAN 21 2016

AREAS AFFECTED...PORTIONS OF SRN KY...NRN TN...AND SERN MO

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 220453Z - 221000Z

SUMMARY...FREEZING RAIN WILL FURTHER EXPAND ACROSS THE MCD AREA OVER
THE NEXT SEVERAL HOURS...WITH RATES OF SEVERAL HUNDREDTHS OF AN INCH
PER HOUR POSSIBLE. FREEZING RAIN WILL GRADUALLY TRANSITION TO SNOW
LATE TONIGHT.

DISCUSSION...THE REGIONAL RADAR MOSAIC DEPICTS PCPN EXPANDING FROM
TN NWD INTO KY...WITH A SECONDARY EXPANSION ACROSS THE MO BOOTHEEL
IN CONJUNCTION WITH A MATURING DEFORMATION BAND. AS MID-LEVEL WAA
INCREASES TO THE EAST OF A DEEPENING LOW ALOFT OVER
LA/AR...ISENTROPIC ASCENT AND STRENGTHENING FRONTOGENETIC
CIRCULATIONS WILL FURTHER SUPPORT PRECIPITATION OVERSPREADING THE
MCD AREA. WHILE SUB-FREEZING SFC TEMPS ARE NOTED ACROSS MUCH OF THIS
AREA...A WARM LAYER NEAR 850 MB IS ENSURING MELTING OF SNOW ALOFT.
POLARIMETRIC DATA /I.E. CC AND ZDR/ FROM KHPX SUGGEST LITTLE
DESCENT/EROSION OF THIS MELTING LAYER...INDICATING THAT FREEZING
RAIN AND SOME SLEET WILL BE PREDOMINANT THROUGH MUCH OF THE
OVERNIGHT...WITH FZRA RATES OF SEVERAL HUNDREDTHS OF AN INCH PER
HOUR POSSIBLE. SLOWLY THROUGH THE OVERNIGHT HOURS...FZRA/SLEET WILL
TRANSITION TO SNOW GENERALLY FROM NORTHWEST TO SOUTHEAST...AS THE
MID LEVELS COOL IN RESPONSE TO STRENGTHENING CAA ALOFT. HEAVIER
SNOWFALL RATES WILL THEN DEVELOP TOWARDS MORNING...AS DEFORMATION
BANDING SPREADS EWD ACROSS WRN TN/KY.

..PICCA.. 01/22/2016

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...MRX...JKL...LMK...OHX...PAH...MEG...

LAT...LON   35898868 35768963 35859027 36679052 37188884 37318618
            36968421 36408445 36278701 35898868

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jan 21, 6:05 PM CSTMesoscale DiscussionSPCArkansas, Ashley, Bradley, Calhoun, Chicot, Clark and 31 more6 hr
Jan 22, 3:58 AM CSTMesoscale DiscussionSPCArkansas, Chicot, Craighead, Crittenden, Cross, Desha and 17 more5 hr
Jan 22, 3:47 AM CSTMesoscale DiscussionSPCAdair, Bell, Boyle, Breathitt, Casey, Clay and 32 more5 hr
Jan 22, 7:30 AM CSTMesoscale DiscussionSPCAdair, Allen, Anderson, Ballard, Barren, Bath and 95 more4 hr
Jan 22, 12:56 PM CSTMesoscale DiscussionSPCAdair, Bath, Bell, Boyd, Boyle, Breathitt and 41 more4 hr

Nearby

Mesoscale Discussions in Kentucky, 2016Mesoscale Discussions in Tennessee, 2016Mesoscale Discussions in Missouri, 2016Every mesoscale discussion in 2016

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.