Severe Thunderstorm Warning 141, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
240 PM CDT TUE AUG 8 2000

WHAT LITTLE SFC OBS AVAILABLE AT 18Z CONTINUES TO SHOW A WARM
FRONT/OUTFLOW BOUNDARY ACROSS WESTERN AND SOUTHERN MO.  GOOD THERMAL
GRADIENT ACROSS BOUNDARY WITH 90S TO AROUND 100 OVER ERN KS AND
NORTHERN AR. ANOTHER SFC TROF EXTENDS FROM CENTRAL NE NORTH INTO WRN MN.
UPPER AIR FEATURES THIS MORNING SHOWED A BROAD TROF FROM THE NRN
ROCKIES THROUGH THE MID MISSISSIPPI VALLEY. A SPEED MAX WAS EVIDENT
MOVING THROUGH NE MT AT 12Z. NOT MUCH TO SPEAK OF IN THE WAY OF
CONVECTIVE DEVELOPMENT YET THIS AFTERNOON.  BEST LOW LVL CONVERGENCE
AND INSTBILITY VICINTY OF SURFACE BOUNDARY OVR WRN IA/ERN NE.
HOWEVER...AREA APPEARS TO BE CAPPED BASED MORNING 700 TEMPS AROUND +13.
MODELS HANDLE BROAD SCALE FEATURES SIMILARLY THE NEXT FEW DAYS...BUT
DIFFER SIGNIFICANTLY IN THE DETAILS.  QPF OUTPUT IS ALL OVER THE
PLACE...ESPECIALLY THROUGH 24 HOURS.  NGM APPEARED HAVE THE BEST
OVERALL HANDLE ON QPF THROUGH 18Z...ESPECIALLY ACROSS ILLINOIS AND
EASTERN MISSOURI AND WILL LEAN TOWARD ITS SOLUTIONS FOR THIS
FORECAST. BELIEVE MOST LIKELY AREA FOR DEVELOPMENT WILL BE FROM
EASTERN IOWA INTO NRN HALF OF ILLINOIS.  WESTERLY 850 FLOW THIS
AFTERNOON AND EVENING SHOULD GET SOME LIFT FROM COOLER AIRMASS OVER
EASTERN IA.  THIS LIFT SHOULD BE ENHANCED THIS EVENING AS S/W /
SPEEDMAX DROPS SOUTHEAST OUT OF THE NORTHERN PLAINS.  WILL GO WITH LOW
CHANCE POPS WEST OF THE MS RIVER AND HIGH CHC POPS OVER IL.  LOOKS
LIKE MOST OF THE ACTIVITY WILL BE DURING THE EVENING HOURS.  AFTER
TONIGHT...E/W FRONTAL BOUNDARY THAT SETS UP OVER SOUTHERN IA/CENTRAL
IL WED WILL DRIFT SLOWLY SOUTH AS HIGH PRESSURE BUILDS TO THE NORTH.
MODELS HINT AT A WEAK S/W MOVING SOUTHEAST ALONG THE BOUNDARY WED
AFTERNOON/EVENING AND WILL INCLUDE LOW CHC POPS SOUTH TO ACCOUNT FOR
THIS FEATURE. WILL GO WITH DRY FCST TO THE NORTH.  COOLER AIR SURGES
SOUTH WEDNESDAY NIGHT AND SHOULD END THREAT OF PCPN FOR THE REMAINDER
OF THE WEEK.

WITH HUMID AIRMASS STILL IN PLACE TONIGHT WARM MINS DEPICTED IN THE
FAN/FWC NUMBERS LOOK REASONABLE.  AFTER TONIGHT IT LOOKS LIKE FWC
MAXES ARE ON THE HIGH SIDE.  WILL UNDERCUT FWC HIGHS ON WED A DEGREE
OR TWO THEN GO CLOSER TO COOLER FAN FOR HIGHS ON THURSDAY.  OVERNIGHT
LOWS SIMILAR ON BOTH MODELS AND LOOK REASONABLE.

IN THE EXTENDED...LONG RANGE MODELS KEEP CWA IN EAST TO SOUTHEAST LOW
LEVEL FLOW OFF HIGH PRESSURE MOVING SOUTH THROUGH THE GREAT LAKES INTO
THE OHIO VALLEY.  WILL CONTINUE THE DRY AND A LITTLE COOLER THAN
NORMAL TREND INTO SUNDAY.

.DVN...
IA...NONE.
IL...NONE.
MO...NONE.

DLF

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
141 AM CDT WED AUG 09 2000

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

0131 AM    VICTOR                    IA   1 INCH HAIL
08/09/00   IOWA                           REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

N