STORM PREDICTION CENTER...NWS/NCEP...NORMAN OK
DAY 1 CONVECTIVE OUTLOOK...REF AWIPS GRAPHIC PGWE46 KWNS.
VALID 232000Z - 241200Z
THERE IS A MDT RISK OF SVR TSTMS THIS AFTERNOON INTO THE OVERNIGHT
HOURS ACROSS MUCH OF NEB...SERN SD...SWRN MN...AND WRN IA. THE MDT
RISK AREA IS TO THE RIGHT OF A LINE FROM 15 E FRM 45 WNW DSM 15 E
BIE 25 S HSI 25 ENE IML 50 WNW LBF 50 NNW MHN 30 W HON 10 ESE ATY
15 NNE RWF 15 E FRM.
SURROUNDING THE MDT RISK AREA...THERE IS A SLGT RISK OF SVR TSTMS
TO THE RIGHT OF A LINE FROM 25 W IWD 15 NNE AUW 20 S MSN 30 NNE MLI
40 WSW OTM 40 ENE SZL 40 NW SGF 40 W CNU 10 NNW SLN 30 SSE MCK 30
SE AKO 15 SW LAR 35 S CPR 45 SSW GCC 30 N PHP 20 NW JMS 20 W RRT.
THERE IS A SLGT RISK OF SVR TSTMS TO THE RIGHT OF A LINE FROM
35 N PVW 40 SW LBB 35 NW MAF 30 ENE MRF 60 NW MRF 30 NNW ROW
30 NW TCC 35 W EHA 15 E EHA 55 NNE AMA 35 N PVW.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 65 SSW GDP
30 NNW GDP 35 SE 4CR 35 SE RTN 55 NE LAA 35 W GLD 20 S DEN
25 ENE CAG 30 N GJT 15 WSW CDC 25 NNE BIH 40 S TVL 35 NE RBL
75 SSE RDM 50 W BKE 40 ENE EPH 40 NNE 4OM ...CONT... 60 N OLF
10 ENE GGW 15 ENE LWT 20 SW BTM 30 NNW IDA 30 SW COD 20 SW SHR
15 WNW 81V 10 SW REJ 35 W BIS 65 NNE DVL ...CONT... 60 WNW ANJ
30 SW MBL 10 N CGX STL 55 SSW UNO 30 ENE FSM 40 ESE END 15 N DDC
25 W GAG 10 ENE MAF 90 SSE MRF.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 10 SE NEL 15 NNE MSV
25 NNW GFL 15 NW EFK.
GEN TSTMS ARE FCST TO THE RIGHT OF A LINE FROM 35 S CRP 45 SSE SAT
30 SE TPL 35 SSW ELD 10 SSE MGR MLB.
...SYNOPSIS...
LARGE UPPER TROUGH OVER THE NWRN CONUS IS FORECAST TO MOVE LITTLE
THROUGH THE END OF THE PERIOD WHILE BELT OF RELATIVELY STRONG /35
TO 50 KT/ SWLY MID-LEVEL FLOW PERSISTS ALONG THE PERIPHERY OF THIS
FEATURE FROM THE CENTRAL ROCKIES NEWD INTO THE UPPER MS VALLEY
REGION.
AT THE SURFACE...MAIN BAROCLINIC ZONE EXTENDS FROM THE ERN DAKOTAS
SSWWD INTO NERN CO...AND THEN WNWWD ACROSS NRN CO INTO SERN WY. IN
ADDITION...SEVERAL OUTFLOW BOUNDARIES ARE EVIDENT...INCLUDING A NW-
SE BOUNDARY EXTENDING FROM SWRN NEB INTO SERN KS.
...CENTRAL AND NRN PLAINS / NRN MS VALLEY REGION...
CLUSTER OF THUNDERSTORMS CONTINUES MOVING NEWD ACROSS W CENTRAL MN
WITH CONTINUED REDEVELOPMENT ALONG THE SWRN FLANK OF THE STORM
CLUSTER WHERE FEED OF MORE UNSTABLE AIR FROM THE SOUTH PERSISTS.
IT APPEARS THAT THIS AREA IS ON THE NRN PERIPHERY OF THE STRONGER
MID-LEVEL FLOW...SUGGESTING A CONTINUED THREAT FOR HAIL / LOCALLY
DAMAGING WINDS.
FURTHER SWWD...WEAK RIDGING ACROSS THE PLAINS IS EVIDENT ON WV
LOOP...WHICH HAS ALLOWED CAP TO PERSIST. IN ADDITION...AIRMASS
ACROSS MUCH OF NEB WAS STABILIZED BY EARLIER CONVECTION...AND THESE
FACTORS HAVE SUPPRESSED CONVECTIVE DEVELOPMENT THUS FAR. A FEW
STORMS HAVE BEGUN TO DEVELOP IN INCREASINGLY MOIST ELY / UPSLOPE
FLOW ACROSS WY...AND AS LOW-LEVEL JET DEVELOPS EARLY THIS
EVENING...EXPECT REMNANT OUTFLOW LYING NW-SE ACROSS KS TO RETREAT
NWD. STORMS SHOULD DEVELOP ALONG THIS RETREATING BOUNDARY AND
INVOF MAIN SURFACE BAROCLINIC ZONE OVER THE NEXT 2 TO 4 HOURS...AND
THEN INCREASE OVERNIGHT AS LOW-LEVEL JET AND ASSOCIATED THETA-E
ADVECTION INCREASES.
SURFACE FLOW REMAINS GENERALLY SELY ACROSS NEB N OF KS OUTFLOW
BOUNDARY...WITH WINDS THEN VEERING TO WLY AND INCREASING TO 35 TO
45 KTS AT MID-LEVELS. THIS COMBINED WITH INCREASINGLY MOIST /
UNSTABLE AIRMASS SUGGESTS THAT STORMS SHOULD RAPIDLY BECOME
SUPERCELLULAR...WITH VERY LARGE HAIL EXPECTED ALONG WITH LOCALLY
DAMAGING WINDS AND A TORNADO OR TWO. OVERNIGHT...STORMS SHOULD
ORGANIZE INTO ONE OR MORE MCS/S...WITH A CONTINUED THREAT FOR
POTENTIALLY DAMAGING WINDS ALONG WITH LARGE HAIL AND A TORNADO OR
TWO.
...SRN HIGH PLAINS...
THUNDERSTORMS CONTINUE TO DEVELOP OVER THE HIGHER TERRAIN OF FAR W
TX...AND ISOLATED STORMS ARE FORECAST TO DEVELOP NWD ACROSS ERN NM
AND POSSIBLY ACROSS THE BORDER INTO WRN PORTIONS OF TX. AIRMASS
HAS BECOME MODERATELY UNSTABLE /1500 TO 2500 J/KG MEAN-LAYER CAPE/
ACROSS THIS REGION...AND 20 TO 30 KT MID-LEVEL FLOW IS CONTRIBUTING
TO SUFFICIENT DEEP-LAYER SHEAR FOR SOME STORM ORGANIZATION /
ROTATION. LARGE HAIL AND LOCALLY-DAMAGING WINDS WILL BE POSSIBLE
INTO THE EVENING HOURS BEFORE STORMS WEAKEN WITH BOUNDARY LAYER
STABILIZATION / RE-ESTABLISHMENT OF LOW-LEVEL CAPPING INVERSION.
...NEW ENGLAND...
A FEW STRONGER STORMS HAVE DEVELOPED ACROSS SRN VT / SRN NH SWD
ACROSS WRN MA...EMBEDDED WITHIN MODERATELY-STRONG NNELY / CYCLONIC
MID-LEVEL FLOW. DAYTIME HEATING HAS CONTRIBUTED TO MODERATE
DESTABILIZATION ACROSS THIS REGION...BUT BOUNDARY LAYER AIRMASS
SHOULD RAPIDLY STABILIZE AFTER SUNSET. UNTIL THEN...AMOUNT OF
INSTABILITY AND MODERATE FLOW ALOFT SUGGESTS A POTENTIAL FOR
MARGINALLY-SEVERE HAIL OR A LOCALLY DAMAGING GUST WITH ONE OR TWO
OF THE STRONGER STORMS.
..GOSS.. 06/23/03
NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED FOR 0100Z
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