DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 211954
SWODY1
SPC AC 211952

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0252 PM CDT THU JUN 21 2012

VALID 212000Z - 221200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
THE OUTLOOK REMAINS GENERALLY UNCHANGED THIS FORECAST ASIDE FROM
SOME SLIGHT TWEAKING OF THUNDER LINES...AS THE GENERAL SEVERE
WEATHER FORECAST REMAINS ON TRACK. STORMS HAVE DEVELOPED ALONG THE
FRONT FROM LK HURON SWWD INTO E CENTRAL IL...WHERE LOCAL/ISOLATED
DAMAGING WIND GUSTS REMAIN POSSIBLE /REF SWOMCD #1237/. STORMS ARE
ALSO ONGOING ALONG THE APPALACHIANS FROM ERN WV SWWD INTO SWRN NC --
WHERE LOW-END/ISOLATED THREAT EXISTS.

WHILE DEVELOPMENT HAS YET TO OCCUR ACROSS THE TX SOUTH PLAINS/E
CENTRAL NM RISK AREA...MODELS SUGGEST ISOLATED DEVELOPMENT IN THE
21Z TO 23Z TIME FRAME...WITH ATTENDANT/ISOLATED THREAT FOR DAMAGING
WINDS AND/OR HAIL.

..GOSS.. 06/21/2012

.PREV DISCUSSION... /ISSUED 1056 AM CDT THU JUN 21 2012/

LITTLE CHANGE TO FORECAST IS NEEDED WITH THE EXCEPTION OF ADDING LOW
SEVERE HAIL/WIND PROBABILITIES ALONG THE FOOTHILLS/HIGHER PEAKS OF
THE CNTRL/SRN APPALACHIANS.

...CNTRL/SRN APPALACHIANS...
PATCHES OF MID-CLOUDS WERE EVIDENT WEST OF THE MOUNTAINS FROM WV SWD
INTO ERN TN AT MID-DAY. EXPECT SFC-BASED CU/TCU TO FORM THIS AFTN
ALONG ERN FRINGES OF THE ACCAS WITH ISOLD/WDLY SCTD TSTMS FORMING
THEREAFTER. REGION REMAINS FAR REMOVED FROM ENHANCED SWLYS ALOFT IN
ADVANCE OF THE UPR TROUGH TO THE N. AS A RESULT...STRONG MULTICELL
STORM STRUCTURES WILL BE THE RULE WITH AN ISOLD WET MICROBURST
AND/OR SVR HAILSTONE POSSIBLE.

...OH VALLEY TO SRN PLAINS...
MIDLVL SHORTWAVE TROUGH OVER THE MID-UPR MS VLY AT MID-DAY WILL
CONTINUE DOWNSTREAM INTO THE GRTLKS REGION THROUGH TONIGHT.
SEGMENTED CDFNT WILL CONTINUE TO MOVE EWD ACROSS THE OH VLY REGION
THIS AFTN/EVE AND SWD ACROSS OK/NW TX.

ELEVATED TSTM CLUSTERS/ACCAS ONGOING FROM PRIMARILY OK INTO WRN AR
WILL LIMIT INSTABILITY THIS AFTN ALONG SRN EXTENT OF THE
FRONT/OUTFLOW BOUNDARIES AMIDST WEAK VERTICAL SHEAR.
MEANWHILE...FARTHER TO THE NE...VSB SATL SUGGESTS LESS CLOUD COVER
FROM THE LWR OH VLY INTO THE CNTRL GRTLKS REGION. HERE...AFTN
MLCAPES WILL RISE INTO THE 1000-1500 J/KG RANGE AHEAD OF THE
APPROACHING CDFNT. WARM SECTOR DEEP LAYER SHEAR AND MIDLVL LAPSE
RATES WILL BE SOMEWHAT WEAK...RENDERING MOSTLY A STRONG MULTICELL
TYPE OF ENVIRONMENT. DMGG WIND GUSTS WILL BE THE PRIMARY THREAT AS
ACTIVITY BECOMES LOOSELY ORGANIZED INTO CLUSTERS/SHORT-LINE
SEGMENTS.

...SOUTH PLAINS INTO E/NE NM THIS AFTERNOON/EVENING...
A WEAK UPSLOPE FLOW REGIME WILL BECOME ESTABLISHED ALONG AND N OF A
COLD FRONT THAT WILL SLOW ITS SWD MOVEMENT TODAY. 12Z SOUNDINGS
FROM AMA/MAF/ABQ REVEAL A LITTLE MORE BUOYANCY THAN FORECAST IN THE
06Z OPERATIONAL RUNS...AND LAPSE RATES WILL BE STEEP ENOUGH TO
SUPPORT A CONDITIONAL RISK FOR HAIL/DAMAGING WINDS THIS
AFTERNOON/EVENING WITH MULTICELL STORMS. HOWEVER...STORM COVERAGE
MAY REMAIN RATHER SPARSE SINCE HEIGHT RISES ARE EXPECTED OVER THE
SRN HIGH PLAINS IN THE WAKE OF THE CENTRAL PLAINS SHORTWAVE TROUGH.

...SW MAINE THIS AFTERNOON/EVENING...
A N-S BAROCLINIC ZONE WILL MOVE LITTLE TODAY ACROSS SW MAINE...WITH
A WARM/SEASONABLY MOIST AIR MASS TO THE W OF THE BOUNDARY. OTHER
THAN THE SURFACE BOUNDARY ITSELF...THERE ARE NO CLEAR SOURCES FOR
ASCENT TODAY ACROSS THIS AREA...IMMEDIATELY E OF THE MIDLEVEL RIDGE.
THOUGH A CONDITIONAL RISK OF DAMAGING WINDS WILL EXIST WITH ANY
STORM ALONG THE FRONT...THE UNCONDITIONAL RISK IS TOO SMALL TO
WARRANT INCLUSION OF PROBABILITIES.

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