DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 031949
SWODY1
SPC AC 031946

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0246 PM CDT TUE JUL 03 2012

VALID 032000Z - 041200Z

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN AND EVE ACROSS
PARTS OF THE NRN PLAINS...

...THERE IS A SLGT RISK OF SVR TSTMS LATE THIS AFTN AND EVE ACROSS
PARTS OF THE GREAT LAKES REGION...

...20Z OUTLOOK UPDATE...
CHANGES TO CATEGORICAL THUNDER...SEVERE AND PROBABILISTIC LINES ARE
GENERALLY MINOR...AND MOSTLY BASED ON TRENDS IN DESTABILIZATION
EVIDENT IN LATEST OBJECTIVE ANALYSES. SLIGHT RISK AREAS OVER PARTS
OF THE NORTHERN PLAINS AND GREAT LAKES BASICALLY DEPICT WHERE THERE
STILL APPEARS POTENTIAL FOR THE DEVELOPMENT OF ONE OR TWO ORGANIZED
STORM CLUSTERS CAPABLE OF GENERATING STRONG WIND GUSTS AND SOME
HAIL. NAM SREF AND HIGH RESOLUTION CONVECTION ALLOWING MODEL DATA
CONTINUE TO SUGGEST ANOTHER POTENTIAL AREA FOR ORGANIZED
STRONG/SEVERE STORM DEVELOPMENT ACROSS PARTS OF CENTRAL/ EASTERN
SOUTH DAKOTA INTO CENTRAL/SOUTHERN MINNESOTA. THIS IS ON THE
NORTHERN PERIPHERY OF MID/UPPER SUBTROPICAL RIDGING...WHERE STEEP
MID-LEVEL LAPSE RATES ASSOCIATED WITH VERY WARM ELEVATED MIXED LAYER
AREA ARE CONTRIBUTING TO LARGE CAPE WITH STRONG DAYTIME HEATING.
HOWEVER...INHIBITION APPEARS CONSIDERABLE...AND MID/UPPER SUPPORT
FOR UPWARD VERTICAL MOTION TO WEAKEN THIS IS NOT CURRENTLY OBVIOUS.


ELSEWHERE...SCATTERED MOSTLY DIURNAL THUNDERSTORM DEVELOPMENT IS
ALREADY WELL UNDERWAY SOUTHEAST OF THE LOWER GREAT LAKES REGION
THROUGH THE OHIO AND MIDDLE MISSISSIPPI VALLEYS...THE APPALACHIANS
AND SOUTHEAST. ADDITIONAL CONVECTIVE DEVELOPMENT IS ONGOING IN
EVOLVING MONSOONAL REGIME ACROSS THE SOUTHERN PLATEAU AND
SOUTHERN/CENTRAL ROCKIES...WHICH SHOULD INCREASE FURTHER THROUGH THE
AFTERNOON. THE RISK FOR LOCALIZED DOWNBURSTS WILL PROBABLY EXIST
WITH ACTIVITY IN MOST AREAS...BUT POTENTIAL FOR ORGANIZED AND
SUSTAINED SEVERE WEATHER POTENTIAL STILL APPEARS LOW TO NEGLIGIBLE.

..KERR.. 07/03/2012

.PREV DISCUSSION... /ISSUED 1115 AM CDT TUE JUL 03 2012/

...NRN HIGH PLAINS...
ROBUST MID-LVL SHORTWAVE TROUGH OVER THE NRN INTERMOUNTAIN W WILL
CONTINUE DOWNSTREAM INTO THE CANADIAN HIGH PLAINS THROUGH TONIGHT.
FALLING PRESSURES/DIURNAL EFFECTS IN ADVANCE OF THIS FEATURE WILL
INDUCE A STRONG LLVL UPSLOPE COMPONENT LATER TODAY...EFFECTIVELY
ADVECTING THE OBSERVED RICH BOUNDARY LAYER MOISTURE IN SD INTO ERN
MT BY LATE AFTN. EML WITH LAPSE RATES IN EXCESS OF 8 DEG C PER KM
IN THE H7-H5 LAYER ATOP THIS RETURNING MOISTURE WILL RESULT IN
MLCAPES OF 1500-2500 J/KG.

ANTICIPATED TRACK OF THE WAVE SUGGESTS THAT THE STRONGEST DCVA WILL
MOVE INTO ALBERTA AND SASKATCHEWAN AND RESULTANT GREATER STORM
COVERAGE SHOULD BE ALONG A CDFNT JUST N OF THE BORDER. GLANCING
INFLUENCE OF THE UPR SYSTEM...HOWEVER...SHOULD ENHANCE THE DIURNAL
CYCLE AND SUPPORT ISOLD TO WDLY SCTD TSTMS BY LATE AFTN/EARLY EVE
OVER CNTRL/ERN MT. FCST HODOGRAPHS SHOW ABOUT 40 KTS OF DEEP-LAYER
SHEAR AND SUPERCELLS EVOLVING INTO BOWING STRUCTURES WILL BE LIKELY
THROUGH THE BULK OF THE EVENING WITH LARGE HAIL AND DMGG WIND GUSTS
SPREADING INTO ND OVERNIGHT.

...GRTLKS TO MID-ATLC CST...
CHALLENGING FCST REMAINS AS WIDESPREAD OUTFLOW/CLOUD COVER CONTINUES
FROM OVERNIGHT STORMS...ALTERING DESTABILIZATION. EARLY AFTN TSTM
CLUSTERS ALONG LAKE ERIE/S SRN SHORE WERE DEVELOPING ALONG A
RESIDUAL OUTFLOW BOUNDARY AND ALONG NRN FRINGE OF RETURNING LLVL
MOISTURE/MID-LVL LAPSE RATES. STORMS WILL LIKELY PROPAGATE SWD INTO
THE UPR OH VLY/CNTRL APPALACHIANS THROUGH PEAK HEATING WITH RISKS
FOR GUSTY/DMGG WINDS AND SOME HAIL. THE STORMS WERE SOMEWHAT
REMOVED FROM STRONGER MID-LVL FLOW...SO A LARGE-SCALE ORGANIZED
EVENT IS NOT EXPECTED. HOWEVER...HAVE ADJUSTED SLIGHT RISK FARTHER
TO THE S AND E.

MEANWHILE...FARTHER N AND W...MORNING SOUNDINGS SUGGESTED THAT STEEP
LAPSE RATES REMAIN FIRMLY IN PLACE ACROSS THE UPR MS VLY AND UPR
GRTLKS REGION. VARIOUS CONVECTION ALLOWING MODELS AND 12Z NAM
SUGGEST THAT MORE TSTMS WILL FORM ALONG THE SYNOPTIC CDFNT OVER THE
GRTLKS REGION AND TRACK ESE ALONG A MLCAPE AXIS OF 2500 J/KG INTO
THE LWR GRTLKS REGION OVERNIGHT. HAVE EXTENDED THE SLIGHT RISK
SLIGHTLY NWD INTO WRN PA AND FAR WRN NY TO ACCOUNT FOR
ACTIVITY...POSSIBLY IN THE FORM OF A FORWARD PROPAGATING SYSTEM BY
12Z WED.

...CNTRL/SRN APPALACHIANS INTO GULF COAST STATES...
12Z REGIONAL SOUNDINGS INDICATE THE POTENTIAL FOR MODERATE-STRONG
AIR MASS DESTABILIZATION TODAY OWING TO THE PRESENCE OF A MOIST
BOUNDARY LAYER AND DAYTIME HEATING. TSTMS ARE EXPECTED TO INCREASE
IN COVERAGE AND INTENSITY THIS AFTERNOON ALONG THE HIGH
TERRAIN...DEVELOPING SEA BREEZE FRONT...AND OUTFLOW BOUNDARIES
REMNANT FROM MONDAY AFTERNOON/EVENING STORMS. WHILE WEAK VERTICAL
SHEAR WILL LIMIT THE POTENTIAL FOR STORM ORGANIZATION/
LONGEVITY...ISOLATED OCCURRENCES OF DAMAGING WIND AND
HAIL ARE POSSIBLE.

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