[BNAWX] Severe Storm Outlook Narrative

[EMWIN Server]

ACUS11 KWNS 041600
SWOMCD
SPC MCD 041559
KYZ000-INZ000-ILZ000-TNZ000-MOZ000-ARZ000-042030-

MESOSCALE DISCUSSION 0064
NWS STORM PREDICTION CENTER NORMAN OK
0959 AM CST TUE FEB 04 2014

AREAS AFFECTED...NERN AR/FAR SERN MO/FAR NWRN TN/WRN KY/FAR SRN IL
AND SWRN IND

CONCERNING...FREEZING RAIN

VALID 041559Z - 042030Z

SUMMARY...FREEZING RAIN WITH RATES RANGING FROM 0.05-0.1 INCH PER
HOUR ARE EXPECTED TO DEVELOP NEWD WITHIN A 75-100 MILE WIDE CORRIDOR
EXTENDING FROM NERN AR TO FAR SRN IL/SWRN IND AND WRN KY.  THIS
PRECIP-TYPE WILL SPREAD ACROSS NERN AR...FAR SERN MO AND FAR NWRN
TN/WRN KY THIS MORNING...AND SHOULD REACH FAR SRN IL...FAR SWRN IND
AND THE REST OF FAR WRN KY AFTER 18Z.

DISCUSSION...AT 15Z...REGIONAL RADAR IMAGERY SHOWED A RATHER LARGE
AREA OF PRECIPITATION SPREADING N/NEWD ACROSS AR...WITH LIGHTNING
DATA INDICATING TSTMS OVER SRN/CENTRAL AR INTO NWRN MS AND ADJACENT
FAR SWRN TN.  AT THE SURFACE...TEMPERATURES HAVE BEEN RISING SLOWLY
TO AROUND 32 F OVER NWRN MS INTO SWRN TN WITH THESE OBSERVATIONS
LOCATED IN THE RELATIVELY WARMER /S-E SIDE/ OF AN INVERTED TROUGH
WHICH EXTENDED FROM FAR SERN AR TO NWRN TN...THEN ENEWD ALONG THE
WRN KY/TN BORDER INTO SOUTH CENTRAL KY.  WHILE SURFACE TEMPERATURES
SHOULD RISE TO ABOVE 32 F IN WRN TN AND PART OF SRN KY INTO THE
AFTERNOON...NELY SURFACE TRAJECTORIES SUGGEST TEMPERATURES ON THE
COOL SIDE OF THE INVERTED TROUGH WILL TEND TO REMAIN BELOW 32 F.

MOISTENING OF AN INITIALLY RELATIVELY DRY LOWER-MID TROPOSPHERE...
PER 12Z REGIONAL SOUNDINGS...IS EXPECTED IN THE LOWER OH VALLEY INTO
THE AFTERNOON.  THIS WILL OCCUR IN RESPONSE TO INCREASING UPWARD
VERTICAL MOTION WITHIN A CORRIDOR OF STRONG DEEP LAYER ASCENT
ATTENDANT TO HEIGHT FALLS AHEAD OF THE SRN PLAINS TROUGH AND STRONG
LOW LEVEL WAA DEVELOPING FROM NERN AR INTO THE LOWER OH VALLEY ALONG
A 50-60 KT LLJ INTO THE DISCUSSION AREA.  ALTHOUGH SOME GUIDANCE
SUGGESTS SURFACE TEMPERATURES WILL RISE ABOVE FREEZING INTO THE
LOWER OH VALLEY LIMITING THE FREEZING RAIN POTENTIAL...THE
EXPECTATION OF SURFACE TRAJECTORIES REMAINING NELY ON THE COOL SIDE
OF THE AFOREMENTIONED INVERTED TROUGH RESULTS IN GREATER CONFIDENCE
THAT SURFACE TEMPS SHOULD REMAIN BELOW 32 F FOR AN EXTENDED PERIOD
THROUGH THE AFTERNOON.  THUS...THE ELEVATED WARM LAYER ALREADY IN
PLACE OVER THE DISCUSSION AREA PER 12Z UPPER AIR ANALYSIS WITH THE
850 MB 0 C ISOTHERM EXTENDING FROM NEAR STL TO SDF AND ADDITIONAL
LOW LEVEL WAA ATOP THE SUB-FREEZING TEMPS WILL RESULT IN FREEZING
RAIN BECOMING THE PRIMARY PRECIP-TYPE INTO THE AFTERNOON.  AN
INCREASE IN PW VALUES TO AROUND 1 INCH SHOULD SUPPORT THE GREATER
PRECIPITATION RATES INTO THE AFTERNOON.  UNTIL THE COLUMN
SATURATES...INITIAL PRECIP-TYPES COULD BE A MIX OF SNOW AND/OR
SLEET...ESPECIALLY WITH NEWD EXTENT INTO THE LOWER OH VALLEY.

..PETERS.. 02/04/2014

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

ATTN...WFO...LMK...OHX...IND...PAH...ILX...MEG...LSX...LZK...

LAT...LON   36029124 36929068 37918949 38628776 38458717 37728687
            37288721 36818788 36018895 35669039 35639105 36029124



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