Probability of damaging thunderstorm winds or wind gusts of 50 knots or higher within 25 miles of a point. Hatched Area: 10% of greater probability of wind gusts 65 knots or greater within 25 miles of a point.
Oklahoma City, OK...Wichita, KS...Springfield, IL...Evansville, IN...Norman, OK...
SPC AC 011958
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0258 PM CDT MON SEP 01 2014
VALID 012000Z - 021200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE KS/OK BORDER AREA TO
THE MID-MS VALLEY...
...THERE IS A SLGT RISK OF SVR TSTMS FOR PARTS OF ERN LOWER MI...
...SUMMARY...
ISOLATED SEVERE STORMS ARE EXPECTED FROM ALONG THE OKLAHOMA/KANSAS
BORDER AREA TOWARDS THE MID-MISSISSIPPI VALLEY THIS EVENING INTO
TONIGHT...AND ACROSS PORTIONS OF LOWER MICHIGAN THIS AFTERNOON.
...KS/OK BORDER AREA TO THE MID-MS VALLEY...
HAVE CONTINUED TO TRIM N/NE EXTENT OF SLIGHT RISK-EQUIVALENT SEVERE
PROBS NEAR THE MID-MS VALLEY OWING TO THE DEARTH OF BUOYANCY SAMPLED
IN 18Z ILX RAOB. THE MOST LIKELY CORRIDOR FOR CONVECTIVE INITIATION
BY 00Z APPEARS TO BE ALONG THE KS/OK BORDER AREA. ALTHOUGH THE 17Z
LMN RAOB SAMPLED A STOUT CAPPING INVERSION...ROBUST HEATING ACROSS
WRN OK SHOULD YIELD NEGLIGIBLE MLCIN BY EARLY EVENING. STEEP
MID-LEVEL LAPSE RATES AND LARGE POTENTIAL BUOYANCY WILL FAVOR
INTENSE UPDRAFTS THAT MAY QUICKLY CONGEAL INTO W/E-ORIENTED CLUSTERS
GIVEN MEAN FLOW PARALLELING THE REMNANT OUTFLOW BOUNDARY. SEE MCD
1657 FOR NEAR-TERM DISCUSSION.
...LOWER MI...
SEVERE RISK ASSOCIATED WITH PORTION OF QLCS OVER NRN LOWER MI WILL
DIMINISH RAPIDLY IN THE NEXT HOUR AS THE LINE PROGRESSES OVER LK
HURON. FARTHER S...LARGE-SCALE ASCENT WILL SHIFT AWAY FROM THE
REGION AS A SHORTWAVE IMPULSE MOVES NE FROM UPPER MI. VEERED
LOW-LEVEL WIND PROFILES SUGGEST CONVECTION WILL REMAIN LESS
ORGANIZED AND MAY ONLY YIELD A LOCALIZED DAMAGING WIND RISK. SEE MCD
1656 FOR NEAR-TERM DISCUSSION.
...CNTRL PLAINS...
SCATTERED CONVECTION HAS FORMED AHEAD OF A SHORTWAVE IMPULSE WITHIN
A STEEP LAPSE-RATE BUT SCANTLY BUOYANT AIR MASS. MODERATE DEEP-LAYER
SHEAR COULD FOSTER MODEST ORGANIZATION WITH A LOW-END SEVERE WIND
AND MARGINAL HAIL RISK THROUGH ABOUT SUNSET. SEE MCD 1658 FOR
NEAR-TERM DISCUSSION.
..GRAMS.. 09/01/2014
.PREV DISCUSSION... /ISSUED 1128 AM CDT MON SEP 01 2014/
...SYNOPSIS...
WATER VAPOR LOOPS INDICATE BROADLY CYCLONIC FLOW EXTENDING FROM
CANADA INTO THE N-CNTRL CONUS...WITH ONE EMBEDDED SHORTWAVE TROUGH
LIFTING NEWD ACROSS PARTS OF THE WRN GREAT LAKES...AND AN UPSTREAM
SPEED MAX EMERGING OVER THE CNTRL HIGH PLAINS. THESE FEATURES WILL
CONTINUE TO ADVANCE THROUGH THE BROADER CYCLONIC FLOW...SERVING TO
MAINTAIN A BELT OF MODERATE TO STRONG MID-LEVEL WLYS/SWLYS FROM THE
CNTRL PLAINS TO THE GREAT LAKES. AN EXTENSIVE SFC FRONT LIES FROM
WRN LAKE SUPERIOR SWWD TO THE TX PANHANDLE. THIS BOUNDARY WILL
ADVANCE EWD ACROSS PARTS OF THE MIDWEST AND GREAT LAKES...WHILE
TRAILING SWWD INTO THE SRN PLAINS AS A STATIONARY FRONT.
...PORTIONS OF THE SOUTHERN PLAINS NORTHEASTWARD TO THE GREAT LAKES
REGION THIS AFTERNOON INTO TONIGHT...
EXTENSIVE CONVECTIVE DEBRIS COVERS THE WARM/MOIST SIDE OF THE
BOUNDARY AT PRESENT. REGARDLESS...SFC DEWPOINTS IN THE UPPER
60S/LOWER 70S EXTEND POLEWARD TO AN OUTFLOW BOUNDARY/PRE-FRONTAL
TROUGH ANALYZED FROM NRN OK TO THE MID-MS VALLEY TO LAKE MI. THIS
WILL SUPPORT CORRIDORS OF AT LEAST MODEST CONDITIONAL INSTABILITY TO
ENHANCE THE POTENTIAL FOR LATER GENERATIONS OF CONVECTIVE
DEVELOPMENT.
THE SEGMENT OF THE OUTFLOW BOUNDARY/PRE-FRONTAL TROUGH FROM THE SRN
PLAINS TO THE OZARKS TROUGH LIES BENEATH AN EML PLUME SAMPLED BY THE
12Z OUN SOUNDING...WHICH FEATURES A PROMINENT WARM LAYER BENEATH
H7-H5 LAPSE RATES AROUND 8.3 C/KM. AS POCKETS OF INSOLATION
MATERIALIZE IN THE WAKE OF ONGOING CLOUDS/PRECIPITATION...MLCAPE
VALUES WILL LIKELY INCREASE TO 2000-3000 J/KG GIVEN THE AMPLE
BOUNDARY MOISTURE DEWPOINTS AND STEEP MID-LEVEL LAPSE RATES. DESPITE
QUASI-NEUTRAL MID-LEVEL HEIGHT TENDENCIES...CONVERGENCE ALONG THE
AFOREMENTIONED SFC BOUNDARIES SHOULD BE SUFFICIENT FOR ISOLATED TO
SCATTERED THUNDERSTORM DEVELOPMENT BY LATE AFTERNOON FROM NERN OK
AND SERN KS INTO SRN MO...WITH ACTIVITY INCREASING IN COVERAGE INTO
THE EVENING HOURS WITH A NOCTURNALLY INCREASING LLJ. THE PRESENCE OF
AROUND 30-40 KT OF EFFECTIVE BULK SHEAR WILL BE SUFFICIENT FOR
INITIALLY ROTATING STORMS...WITH ACTIVITY LIKELY CONGEALING INTO
CONVECTIVE CLUSTERS THAT WILL SPREAD EWD/ESEWD INTO THE OVERNIGHT
HOURS. DMGG WIND GUSTS...LARGE HAIL -- SOME POSSIBLY SIGNIFICANT
DURING INCIPIENT SUPERCELL PHASES -- AND A TORNADO OR TWO WILL BE
POSSIBLE.
MEANWHILE...STRONGER DEEP-LAYER ASCENT RELATED TO THE AFOREMENTIONED
SHORTWAVE TROUGH WILL REMAIN CONFINED TO PORTIONS OF MI DURING THE
NEXT SEVERAL HOURS. DCVA PRECEDING THE TROUGH IS EMERGING OVER AREAS
OF A DIURNALLY HEATED...MOIST BOUNDARY LAYER TO SUPPORT RECENT
THUNDERSTORM DEVELOPMENT OVER WRN LOWER MI. STRONG MID-LEVEL FLOW
ATTENDANT TO THE TROUGH WILL HAVE THE POTENTIAL TO SUPPORT ORGANIZED
MULTICELL CLUSTERS AND PERHAPS A SUPERCELL OR TWO WITH DMGG WIND
GUSTS AND POSSIBLY A TORNADO.
ELSEWHERE...THE AFOREMENTIONED SHORTWAVE TROUGH WILL BECOME
INCREASINGLY REMOVED FROM THE PRE-FRONTAL REGIME BETWEEN THE TWO
SLIGHT-RISK AREAS...WHERE WIDESPREAD CLOUDS ARE STUNTING
DESTABILIZATION AMIDST POOR MID-LEVEL LAPSE RATES. THESE FACTORS
WILL MARGINALIZE THE SVR-TSTM POTENTIAL IN THESE AREAS.
...EASTERN WYOMING / NORTHERN NEBRASKA / SOUTHERN SOUTH DAKOTA...
ASCENT IN THE EXIT REGION OF THE AFOREMENTIONED MID-LEVEL SPEED MAX
WILL ENCOURAGE TSTM DEVELOPMENT THIS AFTERNOON AS STEEP
LOW/MID-LEVEL LAPSE RATES BECOME ESTABLISHED. MID-LEVEL FLOW WILL BE
SUFFICIENTLY STRONG FOR A FEW MULTICELL CLUSTERS WITH SPORADIC SVR
WIND GUSTS POSSIBLE. HOWEVER...THE LACK OF MORE ROBUST
BOUNDARY-LAYER MOISTURE/BUOYANCY SHOULD PREVENT A MORE SUBSTANTIAL
SVR RISK FROM EVOLVING.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
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