Severe Storm Outlook Narrative (AC)
Issued by NWS

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000
ACUS03 KWNS 200726
SWODY3
SPC AC 200724

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0224 AM CDT WED AUG 20 2014

VALID 221200Z - 231200Z

...NO SVR TSTM AREAS FORECAST...

...SUMMARY...
A FEW STRONG STORMS WILL BE POSSIBLE ACROSS PARTS OF THE CENTRAL AND
NORTHERN PLAINS INTO THE MIDDLE MISSOURI VALLEY FRIDAY AFTERNOON
INTO THE OVERNIGHT HOURS. GUSTY WINDS AND HAIL WILL BE THE MAIN
THREATS WITH ANY STORMS THAT DEVELOP.

...SYNOPSIS...

THE UPPER RIDGE OVER THE SRN/CENTRAL U.S. WILL CONTINUE TO BUILD AND
SHIFT EWD ON FRIDAY. AS THIS OCCURS...A SHORTWAVE IMPULSE WILL TRACK
NEWD FROM THE FOUR CORNERS REGION ACROSS THE CENTRAL PLAINS. AT THE
SURFACE...LOW PRESSURE OVER KS/NEB WILL TRACK NE TOWARD WRN IA. A
WEST TO EAST ORIENTED WARM FRONT WILL EXTEND FROM THE LOW ACROSS IA
INTO THE VICINITY OF THE GREAT LAKES. THUNDERSTORMS MAY DEVELOP
AHEAD OF THE SHORTWAVE IMPULSE ACROSS PORTIONS OF THE CENTRAL PLAINS
INTO THE MID/UPPER MS VALLEY...SOME OF WHICH COULD BE STRONG OR
SEVERE.

...PORTIONS OF THE CENTRAL/NORTHERN PLAINS AND MID-MO VALLEY...

QUITE A BIT OF UNCERTAINTY EXISTS CONCERNING SEVERE POTENTIAL ON
FRIDAY. FIRST...SEVERAL ROUNDS OF CONVECTION ARE EXPECTED BETWEEN
THE DAY 1/WED AND DAY 3/FRI PERIOD...AND CLOUD COVER FROM THE
CONVECTION COULD LIMIT HEATING AND LAPSE RATES. SECOND...MODEL
GUIDANCE VARIES IN THE PLACEMENT OF THE SFC LOW ACROSS THE CENTRAL
PLAINS AND ITS EXACT TRACK...WHICH IN TURN HAS RESULTED IN
DIFFERENCES IN THE LOCATION OF THE WARM FRONT. FINALLY...WARMING
MIDLEVEL TEMPERATURES AS THE UPPER RIDGE INTENSIFIES AHEAD OF THE
SHORTWAVE COULD LEAD TO SOME CAPPING CONCERNS. HOWEVER...A VERY
MOIST AIRMASS WILL BE IN PLACE WITH SFC DEWPOINTS NEAR 70 F AS
TEMPERATURES WARM INTO THE 80S AND LOW 90S. AS THE SHORTWAVE
APPROACHES...0-6 KM SHEAR WILL INCREASE TO AROUND 30-40 KT...WHICH
WOULD SUPPORT ORGANIZED STRUCTURES SHOULD STORMS DEVELOP. THE THREAT
DURING THE AFTERNOON APPEARS LARGELY CONDITIONAL AND LIMITED.
HOWEVER...AFTER 00Z CONVECTIVE POTENTIAL MAY INCREASE AS LLJ
STRENGTHENS AND STRONG WARM AIR ADVECTION OVERSPREAD THE WARM FRONT.
GIVEN A GREAT DEAL OF UNCERTAINTY IN HOW SEVERE THREAT WILL
EVOLVE...ONLY LOW-END PROBABILITIES WILL BE MAINTAINED AT THIS TIME.

..LEITMAN.. 08/20/2014



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