Severe Thunderstorm Warning 79, NWS Des Moines, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
305 PM CDT WED MAY 8 2002

PRIMARY FOCUS OF FCST WL BE NEXT SVRL HRS RELATING TO PROGRESSION OF
CDFNT AND WHETHER CAP CAN BE BROKEN.  TWO AREAS OF PRIMARY CONCERN.
19Z SFC ANLYS PLACES LOW INVOF KOTG WITH WRMFNT ALG MN BORDER INTO
NERN IA.  PRES FALLS HAVE BEEN DEEPENING IN THIS AREA IN RESPONSE TO
WV LIFTING INTO MN.  ELEVATED CONVECTION TO OUR N MAY EXPAND SEWD
ALG WRMFNT BUT WL LIKELY NOT DVLP TIL JUST NE OF DMX FA.

LOOKING FARTHER S CDFNT EXTENDS FM LOW ACRS WRN IA INTO CNTL KS.
18Z KSGF/KTOP SOUNDINGS INDC SGFNT WRM LYR ALF BTWN 850/750MB AHD OF
FTN.  17Z STLT DERIVED H7 TEMPS REFLECT THIS AS WELL WITH AOA 10C
TEMPS FM SWRN IA BACK INTO SRN PLAINS.  VISIBLE STLT IMAGERY WAS
INDCG BANDED/OSCILLATING CLDS UNDER CAP PERPENDICULAR TO LOW LVL WND
ACRS ERN KS...BUT CLDS NOW BCMG MORE CELLULR SHOWING CAP MAY BE
LESSENING AND CONVECTION HAS FORMED ALG FNT IN KS.  ON THE OTHER
HAND...CLDS HAVE BEEN SPREADING NEWD INTO FA WHICH MAY LIMIT FURTHER
DESTABILIZATION.  18Z RUC HAS GOOD HANDLE ON FNTL CNVGNC PTN AND
WANTS TO BREAK CAP AFT 21Z AS CNVGNC INCRS A FEW HRS AFT THAT.  DO
NOT HAVE THE GREATEST CONFIDENCE...BUT WL KEEP LIKELY POPS AND SVR
WORDING GOING BANKING ON STRENGTHENING CNVGNC DVLPG LN OF TSTMS ALG
LN STLT IMAGERY NOW SHOWS FM KSPW-KBIE.  WOULD LIKELY SEE SQUALL LN
DVLP WITH WITH CAPES ARND 3000 J/KG.  DEEP SHEAR/HELICITY AND OTHER
SUPERCELL PARAMETERS NOT TOO IMPRESSIVE IN STRAIGHT LN HODOGRAPH BUT
COULD CERTAINLY GET BRIEF SUPERCELLS WITH SVR HAIL AND POSSIBLY WND
BEFORE GOING PREDOMINATELY LINEAR.

PCPN SHOULD END TWRD 06Z SE WITH ATTN TURNING TWRD WND.  SHRT TERM
MDLS IN DECENT AGREEMENT THRU RMNDR OF PD BRINGING STG DVM TMRW
NOTED IN QG FIELDS AND OMEGA ACRS MN/WI BRUSHING IA.  SINCE IT STAYS
N...DO NOT FEEL ADVY WARRANTED BUT WL MENTION 20-30 MPH AND WINDY IN
BODY OF FCST.  CANNOT FIND MUCH REASON TO DEVIATE FM NGM MOS TEMPS.
AVN MOS SEEMS TOO COOL...SPCLLY ON FRI.  AS YOU MIGHT XPC...NGM MOS
NOT CAPTURING STRENGTH OF LOW LVL TEMP GRADIENT ACRS CDFNT BEING TOO
WRM E AND TOO COOL W.  HWVR IT SEEMS TO RECOVER AND BCM REASONAL
LATER TNGT AND INTO FRI SO WL FOLLOW.

XCP FOR SOME UKMET TIMING DIFFERENCES...MED RANGE MDLS INCLUDING 12Z
AVN FAIRLY SIMILAR WITH PTN BUT HAVE SHIFTED WEEKEND SYS FARTHER S.
ALTHOUGH THERE COULD BE SOME SFC BASED DVLPMT EXTRM S INVOF
FNT...ISENT LIFT AND ELEVATED CONVECTION MAY BE BIGGER PCPN
PRODUCER.  H85 THETA-E ADVCTN INCRS LATE FRI NGT AND PERSISTS INTO
SAT EVEN.  SHOWALTER/K INDICES SHOW SHARP INSTABILITY GRADIENT ACRS
SRN ZNS SO WL RELEGATE TSTM MENTION AND LIKELY CATEGORY POPS TO SRN
PTNS.  AVN QPF IMPRESSIVE...AOA 2 INCHES...WITH H85 DWPNTS INTO THE
TEENS AND K INDICES AOA 30 ACRS MO AND INFLOW RGN.  WL HAVE TO WATCH
FOR HVY RAIN EVENT DUE TO BOTH DURATION AND INTENSITY.  STAYED
CLOSER TO COOLER END OF MOS AND OBJECTIVE TEMP NUMBERS WITH PCPN AND
READINGS BLO NML.

.DSM...NONE

SMALL

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
748 PM CDT WED MAY 08 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0534 PM    10 S KELLERTON            IA   1 INCH HAIL
05/08/02   RINGGOLD                       REPORTED BY EMERGENCY
                                          MANAGEMENT.

0537 PM    LAMONI ARPT               IA   59 MPH TSTM GUST
05/08/02   DECATUR                        REPORTED BY ASOS.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
750 PM CDT WED MAY 08 2002

TIME(CDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0659 PM    ATHELSTAN                 IA   .75 INCH HAIL
05/08/02   TAYLOR                         REPORTED BY STORM
                                          SPOTTER.