SPC MD 1547

MD 1547 CONCERNING SEVERE POTENTIAL…WATCH UNLIKELY FOR PORTIONS OF NWRN/CNTRL/S-CNTRL KANSAS AND N-CNTRL OKLAHOMA


MESOSCALE DISCUSSION 1547
NWS STORM PREDICTION CENTER NORMAN OK
1010 PM CDT SAT JUL 27 2013

AREAS AFFECTED...PORTIONS OF NWRN/CNTRL/S-CNTRL KANSAS AND N-CNTRL
OKLAHOMA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 280310Z - 280545Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THE POTENTIAL WILL EXIST FOR STORMS TO PRODUCE ISOLATED
MARGINALLY SVR HAIL INTO THE OVERNIGHT HOURS. WHILE CONVECTIVE
TRENDS WILL BE MONITORED...THE ISSUANCE OF A WW IS CURRENTLY
UNLIKELY.

DISCUSSION...RECENT WATER VAPOR LOOPS INDICATE A MID-LEVEL SPEED MAX
PIVOTING AROUND THE SWRN SEMICIRCLE OF A BROADER GREAT-LAKES-AREA
CYCLONE. AGEOSTROPHIC CIRCULATIONS ACCOMPANYING THIS FEATURE ARE
LIKELY ENHANCING AN 850-700-MB JET STREAM ORIENTED WITH AN
ORTHOGONAL COMPONENT TO A SFC STATIONARY FRONT THAT EXTENDS FROM SFC
LOW PRESSURE IN SERN CO ESEWD INTO W-CNTRL OK. MOIST ISENTROPIC
ASCENT ASSOCIATED WITH THIS FLOW WILL CONTINUE TO FEED A
NW/SE-ORIENTED ARC OF CONVECTION ROOTED AROUND 800-700 MB IN
CNTRL/S-CNTRL KS. THE WAA PATTERN IS WELL DEPICTED BY THE STRONGLY
VERTICALLY VEERING WIND PROFILES/LONG LOOPING HODOGRAPHS EVIDENT IN
DDC/ICT VWP DATA...AND WILL ALLOW THE CONVECTION TO CONTINUE TO
BACKBUILD ACROSS PARTS OF CNTRL/NWRN KS INTO THE OVERNIGHT HOURS.

THE PRESENCE OF AROUND 30-45 KT OF MID-LEVEL FLOW WILL ACT TO
/1/ STEER MESO-BETA ELEMENTS TOWARD THE OKLAHOMA BORDER...AND /2/
YIELD SUFFICIENT SHEAR THROUGH THE CLOUD LAYER FOR ORGANIZED STORM
STRUCTURES INCLUDING ELEVATED SUPERCELLS WITH MARGINALLY SVR HAIL.
THE 00Z LMN AND DDC SOUNDINGS INDICATE MODESTLY STEEP MID-LEVEL
LAPSE RATES AROUND 7 C/KM ACROSS THE AREA...WHICH SHOULD CONTRIBUTE
TO AROUND 500-1000 J/KG OF MUCAPE FOR A MARGINALLY-SVR-HAIL
POTENTIAL. NSSL WDSS-2 DATA SUGGEST THAT SOME OF THE STRONGEST CORES
MAY HAVE PRODUCED QUARTER SIZE HAIL ACROSS PARTS OF S-CNTRL KS.
WHILE STORMS COULD ENTER PARTS OF N-CNTRL OK DURING THE NEXT FEW
HOURS...THEY MAY UNDERGO A WEAKENING TREND WHILE ENCOUNTERING
CAPPING AROUND 700 MB EVIDENT IN THE 00Z LMN RAOB.

AT THIS TIME...THE LACK OF GREATER ELEVATED INSTABILITY WILL LIKELY
PRECLUDE ANY MORE THAN A MARGINAL/ISOLATED SVR-HAIL THREAT...THOUGH
TRENDS WILL BE MONITORED.

..COHEN/CORFIDI.. 07/28/2013

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...TSA...ICT...OUN...GID...DDC...GLD...

LAT...LON   36739795 37009846 38739961 39720050 39820011 38429851
            36929674 36659722 36739795

via SPC Forecast Products http://www.spc.noaa.gov/products/md/md1547.html