SPC MD 38

MD 0038 CONCERNING WINTER MIXED PRECIPITATION FOR PORTIONS OF CENTRAL/EASTERN ARKANSAS...AND FAR NORTHEASTERN LOUISIANA

MESOSCALE DISCUSSION 0038
NWS STORM PREDICTION CENTER NORMAN OK
0605 PM CST THU JAN 21 2016

AREAS AFFECTED...PORTIONS OF CENTRAL/EASTERN ARKANSAS...AND FAR
NORTHEASTERN LOUISIANA

CONCERNING...WINTER MIXED PRECIPITATION 

VALID 220005Z - 220600Z

SUMMARY...PRECIPITATION WILL CONTINUE TO OVERSPREAD PORTIONS OF
CENTRAL AND EASTERN ARKANSAS...AS WELL AS FAR NORTHEASTERN
LOUISIANA...WITH RAIN SLOWLY TRANSITIONING TO FREEZING
RAIN...SLEET...AND SNOW. FREEZING RAIN RATES OF A FEW HUNDREDTHS OF
AN INCH PER HOUR WILL BE POSSIBLE. ADDITIONALLY...SNOWFALL RATES MAY
APPROACH ONE INCH PER HOUR OVERNIGHT...WITH A THUNDERSTORM OR TWO
POSSIBLE.

DISCUSSION...THE LATEST SURFACE ANALYSIS DEPICTS PRESSURE FALLS
UPWARDS OF 3 MB/HR ACROSS NORTHERN LOUISIANA...SIGNALING A RESPONSE
TO DCVA AS A COMPACT VORTICITY MAXIMUM TRANSLATES EWD FROM TX. AS A
SECONDARY IMPULSE /CURRENTLY NOTED OVER SERN KS IN MOISTURE-CHANNEL
IMAGERY/ DROPS SWD AND PHASES WITH THE AFOREMENTIONED IMPULSE...THE
DEVELOPMENT OF A CLOSED LOW ALOFT SHOULD FAVOR AN EXPANDING
DEFORMATION BAND ACROSS PORTIONS OF ARKANSAS AND NRN LOUISIANA THIS
EVENING.

CURRENTLY...SFC TEMPERATURES ARE GENERALLY BELOW FREEZING FROM
LITTLE ROCK NORTHEASTWARD. SUB-FREEZING TEMPS SHOULD GRADUALLY SHIFT
SWD ACROSS THE MCD AREA...AS COLD-AIR ADVECTION STRENGTHENS IN
TANDEM WITH THE DEEPENING LOW. IN TURN...RAIN SHOULD TRANSITION TO A
MIXTURE OF WINTER P-TYPES THROUGH THIS EVENING AND INTO THE
OVERNIGHT HOURS. MOST LOCATIONS WILL INITIALLY EXPERIENCE A MIXTURE
OF FREEZING RAIN/SLEET AS A RESIDUAL WARM LAYER NEAR 850 MB ENSURES
MELTING OF HYDROMETEORS ALOFT. THEREAFTER...A TRANSITION TO SNOW
FROM WEST TO EAST WITHIN THE BAND OF HEAVIEST PCPN WILL OCCUR LATE
THIS EVENING THROUGH THE OVERNIGHT HOURS...AS INCREASING VERTICAL
MOTION...STRONG CAA...AND COOLING DUE TO MELTING SNOW ERODE THE WARM
LAYER. PRIOR TO THE TRANSITION...FREEZING RAIN RATES OF A FEW
HUNDREDTHS OF AN INCH PER HOUR WILL BE POSSIBLE...WHILE LOCALIZED
SNOWFALL RATES COULD APPROACH ONE INCH PER HOUR AFTER THE TRANSITION
AS DENDRITIC GROWTH IS MAXIMIZED ALOFT. MOREOVER...FORECAST
SOUNDINGS SUGGEST SOME WEAK BUOYANCY ALOFT...WHICH COULD FAVOR A
THUNDERSTORM OR TWO...ENHANCING PRECIP RATES.

..PICCA.. 01/22/2016

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

ATTN...WFO...MEG...JAN...LZK...SHV...

LAT...LON   33069224 33699309 34399334 34889309 36179111 36308999
            36088971 32929120 32719184 33069224 

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