MESO: Mesoscale Discussion 0016

ACUS11 KWNS 060606
SWOMCD
SPC MCD 060606
OHZ000-KYZ000-INZ000-ILZ000-TNZ000-MOZ000-ARZ000-061000-

MESOSCALE DISCUSSION 0016
NWS STORM PREDICTION CENTER NORMAN OK
1206 AM CST TUE JAN 06 2009

AREAS AFFECTED...MID-MS/LOWER OH RIVER VALLEYS

CONCERNING...FREEZING RAIN

VALID 060606Z - 061000Z

FREEZING RAIN WILL INCREASE IN AREAL COVERAGE AND INTENSITY
OVERNIGHT. MEAN ICE ACCRETION RATES SHOULD RANGE FROM 0.02 TO 0.05
IN/HR WITH LOCALIZED CONVECTIVELY-INDUCED RATES AOA 0.10 IN/HR
POSSIBLE.

EVENING MODEL GUIDANCE ARE FAIRLY CONSISTENT THROUGH 12Z WITH A
GRADUAL EWD MOVEMENT OF A LEAD MID-LEVEL VORTICITY MAXIMUM
/CURRENTLY STRETCHING FROM SERN KS TO WRN TX PER WATER VAPOR
IMAGERY/. ASCENT ASSOCIATED WITH THIS FEATURE HAS LIKELY AIDED IN
WEAK RADAR ECHOES RECENTLY DEVELOPING OVER THE OZARK PLATEAU. GIVEN
A BROAD LOW-LEVEL WARM/MOIST ADVECTION REGIME DOWNSTREAM OF THIS
/PER REGIONAL PROFILERS AND 00Z HAND-ANALYZED UPPER AIR
CHARTS/...PRECIPITATION INTENSITY/COVERAGE WILL LIKELY INCREASE.
THIS SCENARIO IS SUPPORTED BY OPERATIONAL NAM/NAMKF/GFS ALONG WITH
4-KM WRF-NMM. FORECAST SOUNDINGS SUGGEST THE CONTINUED INFLUX OF
RICHER MOISTURE WOULD RESULT IN WEAK ELEVATED CONVECTIVE INSTABILITY
DEVELOPING TOWARDS 12Z...ENHANCING PRECIPITATION RATES.

RECENT OBJECTIVE ANALYSIS OF THE SURFACE WET-BULB FREEZING LINE
INDICATES A NEARLY STATIONARY CONFIGURATION FROM CNTRL AR NEWD TO
NRN KY. WITH A RELATIVELY BENIGN SURFACE PATTERN LEADING TO MODEST
WINDS...THIS TREND SHOULD CONTINUE. A SLOW NWD PROGRESSION IS
POSSIBLE IF WIDESPREAD PRECIPITATION DEVELOPS...RESULTING IN
SIGNIFICANT DOWNWARD SENSIBLE HEAT FLUX VIA PRECIPITATION FALLING
FROM WARMER LAYER JUST ABOVE SURFACE.

..GRAMS.. 01/06/2009

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

...NOTICE...
SPC WINTER WEATHER MESOSCALE DISCUSSIONS WILL BE ISSUED ON A
SCHEDULED BASIS FROM DECEMBER 1 THROUGH FEBRUARY 28...FOUR
TIMES A DAY...AROUND 00 UTC...06 UTC...12 UTC...AND 18 UTC
FOR SIGNIFICANT SHORT RANGE WINTER WEATHER EVENTS.

ATTN...WFO...ILN...LMK...IND...PAH...ILX...MEG...LSX...LZK...
SGF...

LAT...LON 36369133 36939145 37709112 38219023 38838839 39168696
39438523 39408394 39008372 38578416 38288513 37608695
36848844 36238953 35849055 35989088 36369133

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