756
ACUS1 KMKC 270104
SWODY1
MKC AC 270055

STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWBC.

VALID 270100Z - 271200Z

REF WW 0710...VALID TIL 0300Z
REF WW 0711...VALID TIL 0600Z

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 65 NE
MOT 60 NE BIS 35 N MBG 60 NW REJ 65 NNW ISN.

THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM 25
ENE SGF 40 ESE ICT MHK 20 ENE FNB 25 WSW OTM 35 W MLI 30 WSW MMO 25
NW HUF 25 W SDF 45 WSW CSV 35 NE HSV 25 NNW MSL POF 25 ENE SGF.

GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 ESE 7R4 10 SW LIT
20 ENE FYV 30 NNW END 20 NNW AMA 55 SSE CVS 10 W INK 30 SW P07
...CONT... 10 WSW CZZ 20 ESE RAL 25 N OXR 35 NNE BFL 50 ENE SCK 25
WNW TVL 50 E LOL 50 NNE SUN 30 N LVM 60 NE BIL 60 NNE OLF
...CONT... 75 NNW GFK 20 ENE 9V9 40 NE BUB 15 NNW LNK 30 NNE FNB 15
SSW DBQ 20 SE MKE 30 E PLN ...CONT... 15 NW EFK 40 WSW GFL 45 ESE
BFD 35 SE LBE 35 N RIC 15 NNW FAY 25 ENE CRE.

EARLY EVENING WATER VAPOR IMAGERY SHOWS A LARGE SCALE TROUGH MOVING
INTO THE UPPER OHIO VALLEY...AND POSSIBLY A WEAKER SHORTWAVE TROUGH
MOVING THROUGH EASTERN IOWA INTO NORTHWESTERN ILLINOIS.  ANOTHER
LARGE SCALE TROUGH WAS MOVING ACROSS THE PACIFIC NORTHWEST.  AT THE
SURFACE...A COMPLEX PATTERN OF BOUNDARIES REMAINS IN PLACE OVER THE
CENTRAL U.S.  THE MAIN SYNOPTIC FRONT EXTENDED FROM THE THUMB OF
LOWER MICHIGAN...TO NEAR THE KANSAS CITY MISSOURI AREA TO SOUTH
CENTRAL KANSAS.  OTHER MESOSCALE BOUNDARIES WERE NOTED OVER
SOUTHEASTERN IOWA AS WELL AS CENTRAL ILLINOIS.

...MIDDLE MISSISSIPPI VALLEY...
SCATTERED THUNDERSTORMS CONTINUE TO DEVELOP AND MOVE SOUTHEASTWARD
THROUGH IOWA AND NORTHERN ILLINOIS AS WELL AS WEST CENTRAL
MISSOURI.  SURFACE OBSERVATIONS INDICATE A VERY WARM AND MOIST AIR
MASS REMAINS IN PLACE WITH TEMPERATURES IN THE 80S AND 90S...AND
DEWPOINTS MAINLY IN THE UPPER 60S TO MID 70S.  THIS IS RESULTING IN
A VERY UNSTABLE AIR MASS /AS NOTED ON THE LINCOLN ILLINOIS
SOUNDING/ ACROSS THE AREA...BUT THERE IS STILL A SLIGHT CAP THAT
HAS LIMITED CONVECTION SO FAR.  HOWEVER...IT APPEARS THAT THERE IS
SUFFICIENT CONVERGENCE IN THE VICINITY OF THE BOUNDARIES TO ALLOW
ADDITIONAL STORMS TO DEVELOP THROUGH THE EVENING HOURS.

VAD WIND PROFILES WERE INDICATING GENERALLY UNIDIRECTIONAL FLOW
ALOFT...WITH SPEEDS INCREASING TO 40 KNOTS IN THE MID LEVELS...AND
AS HIGH AS 70 KNOTS AT AROUND 25 KFT AT LINCOLN.  THESE WIND FIELDS
COUPLED WITH THE STRONG INSTABILITY SUGGEST THAT THERE IS A
POTENTIAL FOR DAMAGING WINDS AND LARGE HAIL WITH SOME OF THE
STRONGER STORMS.  THERE IS ALSO SUFFICIENT SPEED SHEAR ALOFT THAT
MAY SUPPORT SOME STORM ROTATION.  THE ACTIVITY MAY EVOLVE INTO A
LINE OF SEVERE STORMS LATER TONIGHT AS THEY MOVE SOUTHEASTWARD
THROUGH THE MID MISSISSIPPI VALLEY INTO THE WESTERN TENNESSEE
VALLEY.

...NORTHERN PLAINS...
SURFACE ANALYSIS SHOWS A PRE-FRONTAL TROUGH EXTENDING FROM JUST
EAST OF GLASGOW MONTANA TO NEAR CHEYENNE WYOMING.  MOISTURE HAS
BEEN ON THE INCREASE THROUGHOUT THE AFTERNOON AS SOUTHEASTERLY LOW
LEVEL FLOW HAS STRENGTHENED AHEAD OF THE APPROACHING NORTHWEST U.S.
TROUGH.  AS A RESULT...THE AIR MASS HAS BEEN BECOMING INCREASINGLY
UNSTABLE THIS AFTERNOON.  THE 00Z BISMARCK SOUNDING SHOWED ABOUT
2000 J/KG OF SURFACE BASED CAPE...AND WITH THE INCREASING LOW LEVEL
MOISTURE AND MID LEVEL COOLING WITH THE APPROACHING TROUGH...CAPE
VALUES SHOULD REMAIN IN 2000 TO 3000 J/KG THROUGH THE EVENING.
STORMS HAVE BEGUN TO DEVELOP ACROSS WESTERN NORTH DAKOTA IN THE
PAST HOUR...AND WITH THE DEGREE OF INSTABILITY...OTHER STORMS ARE
LIKELY...AND SOME WILL LIKELY BECOME SEVERE.  WET BULB ZERO HEIGHTS
ARE SUFFICIENTLY LOW AND STRONG LOW LEVEL VEERING SHOULD SUPPORT
THE POTENTIAL FOR LARGE HAIL WITH SOME OF THE STORMS.  THE EASTWARD
EXTENT OF THE SEVERE STORMS SHOULD BE DETERMINED BY WHERE THE
INSTABILITY WEAKENS.  LATEST SURFACE OBSERVATIONS NOW SUGGEST THAT
AREA IS THE EASTERN DAKOTAS WHERE THE SURFACE RIDGE REMAINS IN
PLACE.

..REHBEIN.. 08/27/00