Severe Storm Outlook Narrative (AC)
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ACUS02 KWNS 261727
SWODY2
SPC AC 261726

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1226 PM CDT FRI AUG 26 2016

VALID 271200Z - 281200Z

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE MID-MO AND MS VALLEYS
EWD INTO OH AND SRN LOWER MI...

...THERE IS A MRGL RISK OF SVR TSTMS FOR PARTS OF THE ERN DAKOTAS
AND WRN/CNTRL MN...

...SUMMARY...
A FEW STRONG TO SEVERE THUNDERSTORMS WITH HAIL AND GUSTY WINDS WILL
BE POSSIBLE ACROSS PARTS OF THE MIDWEST INTO WESTERN MINNESOTA AND
THE EASTERN DAKOTAS.

...SYNOPSIS...
A RELATIVELY ACTIVE NRN STREAM FEATURING MODERATELY STRONG WLY FLOW
ALOFT WILL ENCOMPASS MOST OF THE NRN TIER. PRIMARY FEATURE WITHIN
THIS REGIME WILL BE A MIDLEVEL SHORTWAVE TROUGH MOVING OUT OF THE
DAKOTAS INTO THE UPPER GREAT LAKES...WITH INTENSIFICATION OF AN
ACCOMPANYING SPEED MAX FORECAST TO OCCUR. A PRECEDING BELT OF
MODERATE SWLY FLOW ALOFT WILL EXIST FROM THE CNTRL PLAINS INTO THE
LOWER GREAT LAKES...ALONG THE WRN/NRN PERIPHERY OF A NEARLY
STATIONARY LOW-MIDLEVEL ANTICYCLONE POSITIONED OVER THE MID-ATLANTIC
REGION. AT THE SFC...A WARM FRONT WILL RAPIDLY ADVANCE NWD FROM THE
MID-MS TO MID-OH VALLEYS IN THE MORNING NWD ACROSS WI/MN DURING THE
AFTERNOON/EVENING...WHILE A WEAK COLD FRONT SURGES EWD ACROSS THE
UPPER GREAT LAKES.

...MID-MS VALLEY EWD TO PARTS OF THE GREAT LAKES REGION...
A LEAD UPPER IMPULSE AHEAD OF SYNOPTIC SHORTWAVE TROUGH MOVING
ACROSS THE DAKOTAS/MN WILL QUICKLY MOVE NEWD OVER WI/MI DURING THE
MORNING. AS THIS OCCURS...A WEAK SFC WARM FRONT SHOULD ADVANCE NWD
INTO NRN PORTIONS OF WI AND LOWER MI BY LATE AFTERNOON...WITH RICH
MOISTURE CONTRIBUTING TO A MODESTLY DESTABILIZING AIR MASS S OF THE
WARM FRONT...WHILE MORE ROBUST DESTABILIZATION OCCURS INTO PORTIONS
OF IL/IND AND WRN OH WHERE STRONGER HEATING IS MORE LIKELY TO OCCUR.
ALTHOUGH LARGE-SCALE FORCING FOR ASCENT WILL BE WEAK...A BROADLY
CONFLUENT LOW-LEVEL FLOW REGIME WITHIN THE MOIST/WEAKLY CAPPED AIR
MASS SHOULD CONTRIBUTE TO ISOLATED TO SCATTERED TSTM
DEVELOPMENT...ALTHOUGH UNCERTAINTY REGARDING THE EVOLUTION OF TSTM
DEVELOPMENT IS STILL UNCERTAIN GIVEN THE POTENTIAL LIMITING FACTORS
RELATED TO EARLY CONVECTION AND ASSOCIATED CLOUD COVER. WITH AROUND
30 KT OF MIDLEVEL SWLY FLOW POSITIONED OVER THE
AREA...EFFECTIVE-LAYER SHEAR WILL BE SUFFICIENT TO SUPPORT A FEW
MULTICELL CLUSTERS CAPABLE OF PRODUCING STRONG TO DMGG WIND GUSTS
AND ISOLATED INSTANCES OF LARGE HAIL.

...PARTS OF THE ERN DAKOTAS AND WRN MN...
A PRONOUNCED SHORTWAVE TROUGH...ASSOCIATED WITH AN INTENSIFYING
MIDLEVEL SPEED MAXIMA FEATURING 40-50 KT OF WLY FLOW...WILL MOVE
ACROSS THE ERN DAKOTAS INTO WRN MN BY THE EVENING. AN ASSOCIATED N-S
ORIENTED SFC BOUNDARY MAY SUPPORT THE DEVELOPMENT OF ISOLATED TSTMS
DURING PEAK HEATING ACROSS SERN ND AND NERN SD. DESPITE SFC
TEMPERATURES IN THE 70S F...A CORRIDOR OF UPPER 50S TO LOWER 60S F
DEWPOINTS WILL EXIST BENEATH STEEPENING LAPSE RATES
ALOFT...POTENTIALLY RESULTING IN A SMALL AREA OF MLCAPE VALUES
EXCEEDING 1000 J/KG. A FEW SUPERCELLS WITH A PRIMARY THREAT OF LARGE
HAIL MAY EVOLVE GIVEN THE GRADUALLY VEERING AND MODERATELY STRONG
WIND PROFILES.

..ROGERS.. 08/26/2016

$$


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