Severe Storm Outlook Narrative (AC)
Issued by NWS

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ACUS01 KWNS 240544
SWODY1
SPC AC 240542

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1242 AM CDT WED AUG 24 2016

VALID 241200Z - 251200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PORTIONS OF THE CNTRL
PLAINS AND MID MS VALLEY...

...THERE IS A MRGL RISK OF SVR TSTMS FROM THE SRN HIGH PLAINS NEWD
INTO THE UPPER GREAT LAKES...

...SUMMARY...
SCATTERED STRONG TO SEVERE STORMS PRODUCING STRONG WIND GUSTS AND
HAIL ARE EXPECTED ACROSS PORTIONS OF THE CENTRAL PLAINS AND MIDDLE
MISSISSIPPI VALLEY THIS AFTERNOON AND EVENING.  ISOLATED SEVERE
STORMS WILL BE POSSIBLE FROM THE TEXAS PANHANDLE NORTHEASTWARD INTO
LOWER MICHIGAN.

...SYNOPSIS...
UPPER LOW CURRENTLY CENTERED OVER SRN SASKATCHEWAN IS EXPECTED TO
CONTINUE SLOWLY EWD THROUGH MANITOBA WHILE EVOLVING INTO MORE OF AN
OPEN WAVE. AT THE SAME TIME...A SERIES OF SHORTWAVE TROUGHS WILL
MOVE ACROSS THE PACIFIC NW...NRN GREAT BASIN AND NRN ROCKIES WITH
THE OVERALL EVOLUTION OF THE UPPER LOW AND THESE SHORTWAVES
CONTRIBUTING TO A BROAD TROUGH FROM SRN MANITOBA SWWD INTO NRN CA BY
12Z THU. FARTHER S...SUB-TROPICAL RIDGE WILL REMAIN ANCHORED OVER
THE SE CONUS WHILE CONFLUENT SWLY FLOW PERSISTS BETWEEN THIS RIDGE
AND PREVIOUSLY MENTIONED UPPER TROUGH. SEVERAL CONVECTIVELY INDUCED
SHORTWAVE TROUGHS WILL TRAVERSE THIS CORRIDOR THROUGHOUT THE PERIOD.

...CNTRL PLAINS NEWD INTO THE MID MS VALLEY...
THE SERIES OF SHORTWAVE TROUGHS EXPECTED TO MOVE THROUGH THE CNTRL
PLAINS AND MID MS VALLEY COMPLICATE THE FORECAST AS THEIR
PROGRESSION AND THE STRENGTH OF THEIR ASSOCIATED CONVECTION IS
UNCERTAIN. DETERMINISTIC AND HIGH-RES  GUIDANCE IS IN FAIRLY GOOD
AGREEMENT THAT THE SHOWERS AND TSTMS CURRENTLY ONGOING ACROSS THE TX
S PLAINS GRADUALLY CONTINUE NEWD...REACHING THE CNTRL PLAINS BY
EARLY MORNING AND THE LWR MO VALLEY BY THE AFTERNOON. ASSOCIATED
CLOUD COVER WILL TEMPER HEATING WHILE WARMER MID-LEVEL TEMPERATURES
INCREASE CONVECTIVE INHIBITION. AS A RESULT...STORMS MAY NOT DEVELOP
ACROSS THE CNTRL PLAINS UNTIL THE EVENING WHEN LARGE SCALE FORCING
FOR ASCENT ASSOCIATED WITH ANOTHER SHORTWAVE TROUGH MOVING OUT OF
THE CNTRL ROCKIES REACHES THE REGION AND WAA INCREASES IN RESPONSE
TO THE LLJ.  ONCE STORMS DEVELOP...THE STRONGER MID-LEVEL FLOW WILL
LIKELY BE E OF THE AREA BUT ENOUGH FLOW WILL STILL EXIST TO SUPPORT
OCCASIONALLY STRONG UPDRAFTS CAPABLE OF HAIL. THREAT FOR DAMAGING
WIND GUSTS WILL ALSO EXIST WITH ANY STORMS THAT DEVELOP S OF THE
FRONTAL ZONE.

FARTHER N /ACROSS THE MID MS VALLEY/...TEMPERATURES ARE EXPECTED TO
REACH THE UPPER 80S/LOW 90S AMIDST DEWPOINTS IN THE LOW
70S...SUPPORTING MLCAPE AROUND 2000 J/KG. WITHIN THIS UNSTABLE
ENVIRONMENT...TSTM DEVELOPMENT IS ANTICIPATED ALONG THE OUTFLOW OF
THE SHOWERS/ELEVATED TSTMS ASSOCIATED WITH THE SHORTWAVE MOVING
THROUGH THE REGION DURING THE AFTERNOON. 0-6 KM BULK SHEAR AROUND
40-45 KT IS SUPPORTIVE OF SUPERCELLS /IF THE CONVECTION CAN REMAIN
DISCRETE/ AND ORGANIZED LINE SEGMENTS...WITH A RESULTING THREAT FOR
DAMAGING WIND GUSTS AND HAIL. A LOW TORNADO RISK ALSO EXISTS GIVEN
THE PRESENCE OF MESOSCALE BOUNDARIES AND THE POTENTIAL FOR SOME
LOCALLY BACKED SURFACE WINDS.

...LOWER MI...
LINE OF TSTMS ALONG THE LEADING EDGE OF A SHORTWAVE TROUGH
/ASSOCIATED WITH THE SHOWERS AND TSTMS CURRENTLY ONGOING ACROSS WI/
IS EXPECTED TO MOVE ACROSS LOWER MI DURING AFTERNOON. MODEST FLOW
AND MARGINAL INSTABILITY SHOULD TEMPER THE OVERALL SVR
THREAT...ALTHOUGH ISOLATED DAMAGING WIND GUSTS ARE POSSIBLE.

..MOSIER/DEAN.. 08/24/2016

$$



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