Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 200829
SWODY3
SPC AC 200828

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0228 AM CST SAT DEC 20 2014

VALID 221200Z - 231200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE FROM THE LOWER
MISSISSIPPI VALLEY INTO THE GULF COAST STATES AND NORTHERN FLORIDA
MONDAY AND MONDAY NIGHT.

...SYNOPSIS...

MODEL CONSENSUS IS THAT SYNOPTIC UPPER TROUGH WILL UNDERGO FURTHER
AMPLIFICATION OVER THE CNTRL U.S. EARLY MONDAY AS A STRONG UPPER JET
DROPS SWWD THROUGH THE CNTRL AND SRN ROCKIES. THE UPPER TROUGH WILL
BE ACCOMPANIED BY A COLD FRONT THAT WILL EXTEND FROM THE UPPER MS
VALLEY SWWD THROUGH CNTRL TX BY THE END OF THE PERIOD. FARTHER
DOWNSTREAM...A WARM FRONT WILL LIFT NWD INTO TO THE GULF COAST
REGION MONDAY NIGHT.

...LOWER MS VALLEY REGION...

THE BOUNDARY LAYER OVER THE GULF WILL CONTINUE TO MODIFY WITH A
BROAD FETCH OF SLY NEAR-SFC WINDS SUPPORTING DEWPOINTS IN THE UPPER
60S TO NEAR 70 OFFSHORE AND LOW-MID 60S ADVECTING INLAND MONDAY
NIGHT AS WARM FRONT LIFTS NWD. STEEPER MID-LEVEL LAPSE RATES WILL
SPREAD EWD AND EVENTUALLY INTERCEPT WRN FRINGE OF RICHER LOW-LEVEL
MOISTURE FROM SERN TX INTO THE LOWER MS VALLEY WHERE MUCAPE COULD
APPROACH 1500 J/KG MONDAY NIGHT. CAPE WILL REMAIN MARGINAL FARTHER
EAST INTO THE GULF COAST STATES. SLY LLJ WILL STRENGTHEN OVERNIGHT
AS THE UPPER TROUGH AMPLIFIES...RESULTING IN AN INCREASE IN FORCING
FOR ASCENT. SHOWERS AND A FEW THUNDERSTORMS SHOULD DEVELOP LATER
MONDAY NIGHT...MOST LIKELY ON THE ERN FRINGE OF THE EML WHERE THE
CAP WILL BE WEAKER FROM A PORTION OF THE LOWER MS VALLEY INTO THE
GULF COAST STATES. STRONG EFFECTIVE BULK SHEAR IN PRESENCE OF AT
LEAST MODEST CAPE RAISES CONCERN FOR AT LEAST A MARGINAL SEVERE
RISK. HOWEVER...TIME OF DAY AND LIKELIHOOD THAT RICHER MOISTURE WILL
REMAIN OFFSHORE SUGGEST CONVECTION WILL PROBABLY BE ELEVATED ABOVE A
STABLE SFC LAYER. NEVERTHELESS...A FEW STORMS COULD POSE A THREAT
FOR MARGINALLY SEVERE HAIL.

..DIAL.. 12/20/2014




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