SPC DAY-1 CONVECTIVE OUTLOOK

06 Jun 1999 - 01:02:56 UTC 

ZCZC MKCSWODY1 000
ACUS1 KMKC 060102
MKC AC 060102

CONVECTIVE OUTLOOK...REF AFOS NMCGPH94O.

VALID 060100Z - 061200Z

REF WW NUMBER 391...VALID TIL 0300Z
REF WW NUMBER 392...VALID TIL 0400Z
REF WW NUMBER 393...VALID TIL 0400Z
REF WW NUMBER 394...VALID TIL 0500Z
REF WW NUMBER 395...VALID TIL 0700Z

THERE IS A HIGH RISK OF SVR TSTMS OVER PARTS OF SD AND NEB...TO THE
RIGHT OF A LINE FROM 10 ESE FSD 30 N SUX 45 E BUB 20 E MHN 45 NE
CDR 35 ENE RAP 20 NNW PIR 20 NW BKX 10 ESE FSD.

THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF SD..NEB..MN..IA...TO
THE RIGHT OF A LINE FROM 40 SE HSI 30 ENE MCK 35 NNW CDR 40 SSE REJ
25 WNW AXN 35 NE MSP 35 WSW LSE 20 W ALO 35 NNW OMA 40 SE HSI.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
55 SE OSC 10 WSW MSN 30 NNW 3OI 25 E MHK 25 E CSM 55 NNE AMA
60 N GCK 25 E IML 10 NNW BFF 25 NE 81V 40 SW BIS 45 ENE INL.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
85 SSE MRF 30 N FST 30 N MAF 45 WNW ABI 35 NNW BWD 25 ENE JCT
40 SE DRT.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 25 NW PBG 40 WSW SLK
15 E SYR 50 SE BUF ERI ...CONT... 15 SSE DTW 30 WNW CGX 45 SE OTM
30 WSW JLN 20 SSW FTW 65 WSW COT ...CONT... 50 WSW MRF 45 E 4LJ
40 NW GLD 25 NNE LIC 15 W PUB 20 SW ALS 35 SE PGA 30 ENE P38
60 NW ELY 45 WNW SUN 55 WNW CTB.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 ESE HUM 20 NW MCB
55 NNW MSL 40 NE CSV 25 ESE TYS 35 SE MCN 45 SSW MIA.

...SEVERE THUNDERSTORM FORECAST DISCUSSION...
SHORTWAVE TROUGH AXIS WAS EVIDENT ON EVENING WATER VAPOR IMAGERY
LIFTING NEWD INTO SWRN NEB/FAR NWRN KS AT THIS TIME...AROUND UPPER
LOW OVER WY/CO. THIS FEATURE SHOULD ENHANCE UVV/S INTO THE CENTRAL
AND NRN PLAINS TONIGHT AS IT CONTINUES TO LIFT NWD. SURFACE
PATTERN IS COMPLEX DUE TO NUMEROUS CONVECTIVE BOUNDARIES...HOWEVER
DEEPENING LOW CENTER MOVING INTO N-CENTRAL NEB SHOULD CONTINUE
LIFTING SLOWLY NWD ALONG WITH SHORTWAVE TROUGH OVERNIGHT. THIS IS
ALSO REPRESENTED BY STRONG PRESSURE RISES IN WAKE OF LOW INTO THE
NEB PANHANDLE AT THIS TIME...COUPLED BY STRONG FALLS INTO SWRN SD. 

EVENING SOUNDINGS INDICATE NUMEROUS SEVERE HAIL/WIND AND A FEW
STRONG TORNADOES SHOULD CONTINUE THROUGH THE NIGHT OVER THE
CENTRAL/NRN PLAINS AND INTO THE NRN/CENTRAL GREAT LAKES.

...NEB/SD/IA/MN/SERN ND...
LBF/S SOUNDING WAS VERY FAVORABLE FOR STRONG SUPERCELLS AND
ASSOCIATED TORNADOES INTO WRN NEB/SRN SD AS UPPER SYSTEM LIFTS OUT
...WITH BRN SHEARS NEAR 90 M2/S2 AND SR-HELICITIES OVER 300 M2/S2.
BEST POTENTIAL FOR TORNADIC SUPERCELLS SHOULD THEREFORE REMAIN NEAR
LOW CENTER AND JUST NORTH OF E-W ORIENTED SURFACE FRONT NEAR THE
SD-NEB BORDER...WHERE CONVERGENCE AND BACKED LOW LEVEL FLOW WILL BE
CONCENTRATED FOR A FEW MORE HOURS. INCREASED THREAT SHOULD SPREAD
EWD INTO ERN SD AS SLY LLJ INTENSIFIES AND DEEP LAYER CONVERGENCE
INCREASES LATER THIS EVENING. HOWEVER AS HEATING ABATES AND STRONG
UVV/S INCREASE INTO WEAKLY CAPPED BUT VERY UNSTABLE AIR MASS...
STORMS MAY QUICKLY BECOME MORE WIDESPREAD OVER SD AND DEVELOP INTO
A MCS OVERNIGHT. MCS SHOULD DEVELOP/SPREAD SLOWLY ENEWD ALONG NOSE
OF 40+ KT LLJ WHICH SETS UP BY LATER TONIGHT INTO MN. 

...SRN NEB INTO THE SRN HIGH PLAINS...
EVENING SOUNDINGS ALONG THE HIGH PLAINS YIELDED LITTLE OR NO CAP...
THOUGH DEEP LAYER CONVERGENCE REMAINS WEAK AT THIS TIME AND HAS
LIMITED CONVECTION ALONG DRY LINE. HOWEVER...LATEST RUC GUIDANCE
SUPPORTS EARLIER MODEL RUNS IN INCREASING CONVERGENCE THROUGH H85
ACROSS THIS AREA LATER THIS EVENING. GIVEN AMOUNT OF INSTABILITY
AND SHEAR...WILL THEREFORE MAINTAIN A THREAT OF ISOLATED SEVERE
THUNDERSTORMS OVERNIGHT INTO THE HIGH PLAINS...MAINLY FROM THE
OK/TX PANHANDLES NWD WHERE EWD PUSH WILL BE STRONGER.

SEPARATE AREA OF CONVECTION INTO SWRN TX MAY ALSO CONTINUE TO
PRODUCE SEVERE WEATHER WITHIN STRONGLY UNSTABLE AIR MASS FOR A FEW
MORE HOURS. HOWEVER...DRY LINE IS EXPECTED TO RETREAT WWD
OVERNIGHT AND WILL LIMIT CONVERGENCE THIS FAR SOUTH LATER THIS
EVENING.

...GREAT LAKES...
WARM FRONT APPEARED TO EXTEND FROM SRN MN INTO THE NERN WI AND THE
NRN GREAT LAKES EARLY THIS EVENING. THIS BOUNDARY WILL LIKELY MOVE
LITTLE OVERNIGHT...AND SHOULD SUPPORT GRADUAL EWD MOVEMENT OF
ONGOING ACTIVITY MOVING INTO NRN WI UNDER 40-50 KT WLY MID LEVEL
FLOW. EVENING SOUNDINGS REMAIN FAVORABLE FOR SEVERE CONVECTION
INCLUDING ISOLATED SUPERCELLS...THOUGH LARGE SCALE SUPPORT WILL BE
LIMITED AS STRONG LLJ DEVELOPS INTO IA AND MN.

..EVANS.. 06/06/99

NNNN


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