DAY1SVR: Day 1 Convective Outlook

ACUS01 KWNS 062006
SWODY1
SPC AC 062004

DAY 1 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0304 PM CDT FRI JUL 06 2012

VALID 062000Z - 071200Z

...THERE IS A SLGT RISK OF SVR TSTMS FROM EASTERN SD EASTWARD ACROSS
PORTIONS OF MN...WI...AND LOWER MI...

...THERE IS A SLGT RISK OF SVR TSTMS FROM NORTHERN LA/MUCH OF MS
NORTHWARD ACROSS WESTERN TN/NORTHWEST AL...

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS NORTHERN ME...

CHANGES TO THE 20Z OUTLOOK INCLUDE A NORTHWARD EXTENSION OF THE
SLIGHT RISK INTO WESTERN TN/NORTHWEST AL. A CLUSTER OF TSTMS
PRODUCING DAMAGING WINDS WILL LIKELY CONTINUE MOVING SOUTHWEST FOR
THE NEXT FEW HOURS IN AN AXIS OF STRONG INSTABILITY WITH SBCAPE
VALUES OF AROUND 3000 J/KG. REF MCD 1418 FOR THE LATEST THINKING ON
SHORT-TERM TRENDS IN THIS AREA.

THE 5 PERCENT WIND PROBABILITIES WERE EXTENDED INTO SOUTHERN MO
WHERE TSTMS HAVE DEVELOPED AS A RESULT OF VERY STRONG HEATING. GIVEN
THE LARGE TEMP-DEW POINT SPREADS...THE STRONGEST STORMS WILL BE
CAPABLE OF DAMAGING DOWNBURST WINDS.

HAVE ALSO EXTENDED THE 5 PERCENT WIND PROBABILITIES SOUTHWARD OVER
NORTHERN IND WHERE ISOLATED TSTMS HAVE DEVELOPED. ADDITIONAL TSTMS
MAY DEVELOP IN A VERY UNSTABLE AND UNCAPPED AIR MASS IN PROXIMITY TO
EASTWARD-MOVING LAKE BREEZE FROM LAKE MICHIGAN.

HAVE KEPT THE UPPER MIDWEST SLIGHT RISK INTACT AS LATEST VISIBLE
IMAGERY CONTINUES TO SUGGEST CU FIELD IS BECOMING BETTER ESTABLISHED
OVER EASTERN SD/WEST-CENTRAL MN. ENVIRONMENT WILL BE FAVORABLE FOR
SVR TSTMS GIVEN INSTABILITY/SHEAR IN PLACE AS DISCUSSED IN PREVIOUS
OUTLOOK.

..BUNTING.. 07/06/2012

.PREV DISCUSSION... /ISSUED 1111 AM CDT FRI JUL 06 2012/

...UPR MIDWEST...
HEALTHY NOCTURNAL MCS HAS DIURNALLY WEAKENED OVER NRN MN WITH ONLY
REMAINING STRONG CONVECTION OF ELEVATED VARIETY ACROSS THE UPR
GRTLKS REGION. DESPITE BEING ELEVATED...GUSTY WINDS CAN STILL BE
EXPECTED WITH ACTIVITY MOVING ACROSS NERN MN AND LKSUP REGION
THROUGH EARLY AFTN.

LATER THIS AFTN...A CHALLENGING FCST HAS UNFOLDED. AS MID/UPR LVL
CLOUD CANOPY FROM EARLY MCS THINS/DIMINISHES...VERY STRONG LLVL
HEATING WILL COMMENCE ALONG/S OF AN E-W ORIENTED FRONT ACROSS ERN SD
INTO WI. MORNING SOUNDINGS SUGGEST THAT WARMING WILL TAKE PLACE IN
THE H7-H5 LAYER...FURTHER COMPLICATING MATTERS AS CINH LIKELY
INCREASES. IN FACT...LATEST DETERMINISTIC AND SREF GUIDANCE SUGGEST
THAT ANY STORM INITIATION WILL LIKELY BE N OF THE FRONT WITH LITTLE
IF ANYTHING FORMING IN THE WARM SECTOR. AS A RESULT...THIS OUTLOOK
HAS TRIMMED ALONG SRN EDGE OF ONGOING SLIGHT RISK. BUT...OUTLOOK
WILL MAINTAIN AT LEAST A SMALL PROBABILITY OF TSTMS DEVELOPING S OF
THE FRONT. IF THIS OCCURS...UPSCALE GROWTH INTO BOWS AND LEWPS WITH
DMGG WINDS...LARGE HAIL AND PERHAPS A BRIEF TORNADO COULD OCCUR.
THESE STORMS WOULD REACH THE CNTRL GRTLKS LATER TONIGHT.

OTHERWISE...AT A SLIGHTLY HIGHER PROBABILITY...STORMS DEVELOPING N
OF THE FRONT WILL LIKELY PRODUCE LARGE HAIL GIVEN THE STEEP LAPSE
RATE ENVIRONMENT AND WIND SHEAR OF 40-50 KTS. ACTIVITY WILL TEND TO
BACKBUILD SWWD ALONG THE COLD FRONT TOWARD SFC LOW PRESSURE IN SERN
SD DURING THE EVENING WITH SIMILAR SVR RISKS AND EWD INTO THE UPR
GRTLKS REGION OVERNIGHT.

...CNTRL HIGH PLAINS...
RELATIVELY MOIST UPSLOPE FLOW ALONG THE PALMER DIVIDE AND MLCAPE
500-1000 J/KG WILL BE FAVORABLE FOR HIGH-BASED TSTMS OVER NERN CO
AND SWRN NEB LATER THIS AFTN/EVE. STORMS WILL LIKELY FORM INTO
MULTICELL CLUSTERS GIVING AT LEAST ISOLD DMGG WIND GUSTS AND HAIL.
A SMALL AND LOOSELY ORGANIZED MCS WITH DECREASING SEVERE TRENDS WILL
MOVE EWD INTO THE LWR NEB PLAINS OVERNIGHT.

...SRN/SERN STATES...
THIS OUTLOOK UPDATE WILL INCLUDE A SLIGHT RISK UPGRADE FOR DMGG
WINDS/HAIL ACROSS PORTIONS OF SE AR...LA AND SWRN MS.

12Z DIAGNOSTIC DATA SUGGEST THAT RELATIVELY COLD POCKET ALOFT /MINUS
8 DEG C AT H5/ HAD ADVECTED SWWD ATOP PRECIPITABLE WATER VALUES IN
EXCESS OF 1.75 INCHES OVER PARTS OF THE MID-SOUTH/LWR MS VLY. WHILE
ISOLD TSTMS WITH HYBRID/WET MICROBURSTS WILL BE POSSIBLE AT RANDOM
LOCATIONS ACROSS THE FAR ERN CAROLINAS AND SRN GA...A MORE ORGANIZED
DOWNBURST THREAT MAY BE EVOLVING ALONG WRN FRINGE OF A SUB-SYNOPTIC
ENTITY IN SWRN/CNTRL MS /WHERE ENELY MID-LVL FLOW IS SOMEWHAT
ENHANCED/. HERE...FCST SOUNDINGS EXHIBIT A STEEP LAPSE RATE FROM
SFC-500 MB AND WITH FURTHER COOLING ALOFT/HEATING IN THE BOUNDARY
LAYER...STRONG MULTICELLS MAY YIELD A FEW DMGG HYBRID/WET
MICROBURSTS AND HAIL. ACTIVITY WILL PROPAGATE WSW INTO PARTS OF
SERN AR AND LA THIS EVE BEFORE DIMINISHING WITH SUNSET.

...NRN ME...
H5 ANALYSIS PLACES NEW ENGLAND WITHIN A LARGE SCALE RIDGE AXIS THIS
MORNING. HOWEVER...BY LATE THIS AFTN/EVE...A MID-LVL TROUGH OVER
CNTRL QUEBEC WILL ROTATE INTO THE ST. LAWRENCE VLY...WITH IT/S
GLANCING INFLUENCE PASSING BY NRN ME. 12Z CAR SOUNDING CONVECTIVE
PARAMETERS WERE NOT PARTICULARLY IMPRESSIVE...BUT UPSTREAM MANIWAKI
QUEBEC DATA EXHIBITS SLIGHTLY STEEPER LAPSE RATES AND STRONGER WNW
FLOW REGIME. EXPECT A FEW TSTMS WILL DEVELOP THIS AFTN OVER CNTRL
QUEBEC NEAR THE AFOREMENTIONED WAVE AND THEN AFFECT PARTS OF NRN ME
THIS EVE. THERMO/KINEMATIC ENVIRONMENTS WILL BE SUPPORTIVE OF FAST
MOVING LINE SEGMENTS BY EVENING WITH DMGG WINDS AND PERHAPS HAIL THE
PRIMARY THREATS. THE LACK OF SUBSTANTIAL INSTABILITY PRECLUDES A
WIDESPREAD EVENT.

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