SPC AC 132000
DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0300 PM CDT SUN JUN 13 2010
VALID 132000Z - 141200Z
...THERE IS A SLGT RISK OF SVR TSTMS FROM THE SOUTHERN HIGH PLAINS
TO THE MIDWEST...
...SOUTHERN PLAINS...
PRIOR FORECAST REASONING GENERALLY REMAINS UNCHANGED...ALTHOUGH
ADJUSTMENTS WERE MADE TO THE SLIGHT RISK/SEVERE PROBABILITIES ACROSS
WEST CENTRAL/NORTHERN KS WHERE THE AIRMASS HAS
RECOVERED/DESTABILIZED NEAR/SOUTH OF THE SYNOPTIC FRONT.
OTHERWISE...REFERENCE TORNADO WATCH 311 AND ASSOCIATED MESOSCALE
DISCUSSIONS FOR THE LATEST DETAILS.
...MIDWEST...
18Z SPECIAL OBSERVED RAOBS FROM SPRINGFIELD MO/LINCOLN IL SAMPLE THE
WEAKLY CAPPED/VERY UNSTABLE BOUNDARY LAYER ALONG/SOUTH OF AN
EFFECTIVE WEST-EAST SURFACE FRONT...WITH UPWARDS OF 2000-3000 J/KG
MLCAPE FROM MO INTO CENTRAL/SOUTHERN IL AND WESTERN INDIANA AT MID
AFTERNOON. AIDED BY AN EASTERN IA MCV...MULTICELLULAR/LINEAR
CLUSTERS WITH WIND DAMAGE/SOME HAIL POTENTIAL WILL REMAIN COMMON
THROUGH EARLY EVENING ESPECIALLY WITHIN A CORRIDOR FROM CENTRAL MO
TO CENTRAL INDIANA. A DIMINISHING INTENSITY TREND IS ANTICIPATED
POST-SUNSET.
...CAROLINAS...
A LOOSELY ORGANIZED CLUSTER OF STRONG/SEVERE STORMS WILL CONTINUE TO
ADVANCE SOUTHEASTWARD MAINLY ACROSS THE NC PIEDMONT OVER THE NEXT
FEW HOURS. BOUTS OF DAMAGING WINDS WILL REMAIN POSSIBLE...BUT
OVERALL SCENARIO SHOULD REMAIN RELATIVELY MARGINAL AND CONFINED TO
THE NEXT FEW HOURS PRE-SUNSET.
..GUYER.. 06/13/2010
.PREV DISCUSSION... /ISSUED 1136 AM CDT SUN JUN 13 2010/
...SRN PLAINS...
WHILE DEEP-LAYER FRONTAL ZONE APPEARS TO BE SITUATED FROM NWRN KS
NEWD INTO IA THIS MORNING...ZONE OF STRONGEST LOW LEVEL
CONVERGENCE...COINCIDENT WITH PRONOUNCED SURFACE INSTABILITY
GRADIENT...LIES TO THE SOUTH OF REMNANT MCS DEBRIS...FROM NERN TX
PNHDL ACROSS SCNTRL/SERN KS...NEWD INTO NRN/CNTRL MO. AIRMASS ALONG
AND SOUTH OF THIS ZONE WILL CONTINUE TO DESTABILIZE THROUGH THE
AFTERNOON WITH VERY MOIST BOUNDARY LAYER AND MODEST HEATING THROUGH
SCATTERED TO BROKEN CLOUD DECK CONTRIBUTING TO MLCAPE OF 2000-3000
J/KG.
SIMILAR TO SATURDAY...LARGE SCALE ASCENT ACROSS THE REGION WILL
REMAIN SUBTLE/WEAK AS THE UPPER TROUGH TO THE WEST MAKES ONLY SLOW
EWD PROGRESS AND BEGINS TO EVOLVE INTO A MORE PROGRESSIVE OPEN WAVE.
UNLIKE SATURDAY...MID LEVEL FLOW MAY BECOME A BIT STRONGER THROUGH
THE DAY. HOWEVER...MID LEVEL TEMPERATURES...ESPECIALLY ACROSS PARTS
OF WEST TX...MAY BE A BIT WARMER THAN PAST DAYS.
ALL INDICATIONS ARE THAT ANOTHER ROUND OF VIGOROUS DEEP CONVECTION
WILL DEVELOP THIS AFTERNOON ALONG THE STALLED BOUNDARY FROM THE
PNHDL NEWD INTO KS AS HEATING AND PERSISTENT LOW LEVEL FORCING ACT
TO OVERCOME INHIBITION. GIVEN AT LEAST 40KT SWLY FLOW
ALOFT...EFFECTIVE SHEAR WILL AGAIN BE FAVORABLE FOR STOUT ROTATING
UPDRAFTS CAPABLE OF PRODUCING HAIL AND DAMAGING WINDS.
THE GREATER PROBABILITY FOR SUPERCELLS WITH A COUPLE OF TORNADOES
WILL EXIST ALONG THE BOUNDARY WHERE LOW-LEVEL SHEAR WILL BE GREATER
AND COEXIST WITH HIGHER BOUNDARY LAYER RH/LOWER LFC. INITIAL ROUND
OF LATE AFTERNOON SUPERCELLS WILL LIKELY MERGE AND GROW UPSCALE TO
SOME EXTENT WITH AN MCS LIKELY TO SPREAD NEWD ACROSS NW/N CENTRAL OK
TO SERN KS...AND PERHAPS AS FAR AS WRN MO BY EARLY MONDAY. SOME RISK
FOR DAMAGING WINDS AND HAIL WILL ACCOMPANY THIS ACTIVITY AFTER DARK.
...MIDWEST FROM MO ACROSS IL/WRN IND...
CONVECTIVELY ENHANCED FRONTAL WAVE/MCV OVER IA...AND RESIDUAL COLD
POOL EXTENDING SWWD ACROSS NRN MO AND INTO ERN KS...WILL SPREAD EAST
THIS AFTERNOON AND PROMOTE ASCENT ACROSS A STEADILY DESTABILIZING
AIRMASS FROM CNTRL MO EWD ACROSS IL. WRF-HRRR HAS BEEN CONSISTENT IN
FORECASTING A SUBSTANTIAL INCREASE IN CONVECTION AMIDST THE LARGER
CIRCULATION MOVING EAST THROUGH EARLY EVENING.
REGION IS CURRENTLY EXPERIENCING NEARLY FULL INSOLATION AND EXPECT
CONTINUED STRONG DESTABILIZATION COUPLED WITH GRADUAL INCREASE IN
ASCENT SHOULD EFFECTIVELY REMOVE REMAINING INHIBITION AND LEAD TO AN
INCREASE IN STORMS. MID LEVEL FLOW...WHILE NOT PARTICULARLY
STRONG...SHOULD INCREASE WITH THE APPROACH OF THE MCV AND PROVE
SUFFICIENT FOR PERSISTENT MULTICELL CLUSTERS/BANDS OF STORMS WITH
HAIL AND WIND DAMAGE POTENTIAL.
...CNTRL APPALACHIANS TO MID ATLANTIC...
WHILE ONE SHORT WAVE HAS PASSED OFFSHORE...ANOTHER WEAK SYSTEM IS
CRESTING THE APPALACHIANS ATTM /REF MCD 919/. AN INCREASE IN
PRIMARILY DIURNALLY/DIABATICALLY DRIVE CONVECTION APPEAR LIKELY OVER
A LARGE AREA THIS AFTERNOON. STRONG INSTABILITY AND HIGH HEAT WILL
FAVOR LOCALLY DAMAGING DOWNBURST WINDS ACROSS PARTS OF VA/NC.
FARTHER NORTH...FROM DELMARVA ACROSS NJ....SLIGHTLY STRONGER MID
LEVEL FLOW...BUT LESS INSTABILITY...COULD SUPPORT A FEW SUPERCELLS
WITH HAIL/WIND. AREAL/TEMPORAL COVERAGE OF THESE THREATS DOES NOT
APPEAR TO SUPPORT HIGHER SEVERE PROBABILITIES AT THIS TIME.
CLICK TO GET WUUS01 PTSDY1 PRODUCT
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z
|
