Severe Thunderstorm Warning 138, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
245 PM CDT SUN AUG 6 2000

TSRA ERUPTED EARLY THIS AFTERNOON ALONG COLD FRONT FROM NEAR DBQ
SOUTHWEST THROUGH DMX VICINITY.  FAR SOUTHERN COUNTIES OF CWA ALSO
UNDER THE GUN AS TSRA DEVELOPED IN ELEVATED CONFLUENT AREA OVER NORTHERN
MISSOURI. EXPECT TSRA ALONG FRONT TO PUSH SOUTHEAST THRU EARLY EVENING
WITH FRONT WITH DRIER LOW LEVEL AIR SPREADING IN BEHIND.  AFTERNOON
DEWPOINTS TO THE NORTHWEST IN THE LOWER 60S LATE THIS AFTERNOON AND
EXPECT TO SEE THESE OVER NORTHWEST HALF OF CWA TONIGHT.  WILL END THE
TSRA NW TO SE THIS EVENING AND CLEAR OUT MOST OF CWA.  CURRENT FCST
HAS TEMPS IN THE LOW 60S NORTH TONIGHT AND MID TO UPPER 60S SOUTH WHICH
LOOKS REASONABLE.  WILL INCLUDE A MENTION OF LATE NIGHT FOG SOUTH WITH
THIS EVENINGS STORMS MOISTENING THE GROUND AND LIGHT WINDS OVER NIGHT.

MODELS ALL PUSH THE FRONT INTO NORTHERN MISSOURI TONIGHT AND BRING IT
BACK NORTH MONDAY AS LOW PRESSURE DEVELOPS OVER THE PLAINS.  NGM HAS
THE NORTHERN MOST POSITION BY MONDAY EVENING WITH THE PLAINS LOW OVER
THE DAKOTAS AND WARM FRONT ACROSS SRN MN.  BELIEVE AVN/ETA POSITION IS
MORE REALISTIC WITH A NEBRASKA SFC LOW POSITION AND WARM FRONT THROUGH
CENTRAL IA/NRN IL.  WARM HUMID CONDITIONS WILL SPREAD NORTH BEHIND
FRONT THROUGH CENTRAL THIRD OF CWA ON MONDAY.  NO UPPER FORCING APPARENT
MONDAY AND LOW LEVEL WINDS WILL BE WEAK IN THE VICINITY OF THE WARM
FRONT SO WILL LEAVE POPS OUT FOR MONDAY.  SHOULD SEE MCS DEVELOPMENT
AHEAD OF NE SFC LOW MONDAY EVE/NIGHT AND MOVE EAST ALONG BOUNDARY WILL
GO WITH CHANCE POPS FOR NOW AND INCLUDE MENTION LOCALLY HEAVY RAIN
ALONG AND SOUTH OF EXPECTED BOUNDARY POSITION.  SFC FRONT/TROUGH SETS
UP OVER NORTHWEST IA BY TUESDAY WITH AVN MOVING FRONT THROUGH FASTER
THAN ETA BY TUESDAY EVENING.  WILL OPT TO GO WITH THE SLOWER ETA SINCE
AVN APPEARS TO STENGTHING SFC HIGH OVER NORTHERN ROCKIES MORE THAN THE
OTHER MODELS.  WILL GO WITH CHANCE POPS TUESDAY  AND TUESDAY NIGHT
NIGHT AS SYSTEM PUSHES SOUTHEAST INTO REGION.

FAN/FWC LOWS LOOK REASONABLE FOR TONIGHT.  MONDAY WILL GO WITH THE WARM
FWC IN THE WARM SECTOR AND TREND TOWARD COOLER FAN TO THE NORTH.  WILL
GO WITH THE WARMER FWC NUMBERS FOR TUESDAY WITH APPROACHING FRONT.

EXTENDED MODELS SHOW UPPER FLOW AMPLIFYING OVER U.S. PLACING MID
MISSISSIPPI VALLEY IN STRONG NW FLOW BY THE END OF THE WEEK.  IN THE
TRANSITION PERIOD...WEDNESDAY AND THURSDAY...SURFACE FRONT MOVES SOUTH
THROUGH THE REGION. UKMET AND MRF ARE CLOSE WITH THIS SOLUTION WHILE
YESTERDAYS ECMWF RUN WAS FASTER AND MUCH STRONGER. BASED ON THE
MRF/UKMET SOLUTION WILL CONTINUE PRECIP CHANCES WEDNESDAY AND
WEDNESDAY NIGHT THEN PRECIP CHANCES SHIFT SOUTH THURSDAY WITH FRONT.
FRIDAY SHOULD BE DRY WITH HIGH PRESSURE BUILDING OVER AREA.  ONLY
CHANGE TO GOING EXTENDED FOR WEDNESDAY/THURSDAY WILL BE TO DROP PRECIP
CHANCES OVER THE NORTHERN HALF AND WILL CONTINUE CHANCE ACROSS SOUTH
WITH SFC FRONT CLOSE BY.

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

DLF

IAZ040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-002-007-
009-015>018-024>026-034-035-MOZ009-010-071000-

SIGNIFICANT WEATHER OUTLOOK
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1207 PM CDT SUN AUG 6 2000

...SCATTERED STRONG TO SEVERE STORMS POSSIBLE THIS AFTERNOON INTO
EARLY EVENING...

A WEAK COLD FRONT NEAR A LINE FROM WATERLOO TO DES MOINES WILL MOVE
SLOWLY EAST REACHING THE MISSISSIPPI RIVER BY EARLY EVENING.
MEANWHILE...AN UPPER AIR DISTURBANCE MOVING THROUGH WESTERN IOWA
WILL INTERACT WITH THE FRONT TO IGNITE SCATTERED THUNDERSTORMS OVER
THE AREA BY MID AFTERNOON. THE AIR AHEAD OF THIS FRONT IS VERY MOIST
WITH DEWPOINTS WELL INTO THE 70S. THIS COMBINED WITH AMPLE SUNSHINE
HAS LED TO A VERY UNSTABLE AIRMASS WITH CAPES IN EXCESS OF 3000 J/KG
AND LIFTED INDICES OF -5 TO -10. STORMS WHICH DEVELOP WILL CONTAIN
TORRENTIAL RAIN...AND HAVE THE POTENTIAL TO PRODUCE LARGE HAIL AND
DAMAGING WINDS. AN ISOLATED TORNADO WILL ALSO BE POSSIBLE...MAINLY IN
ILLINOIS WHERE SHEAR WILL BE GREATEST. THE AREAS MOST SUSCEPTIBLE FOR
STRONG TO SEVERE STORMS WILL GENERALLY BE EAST OF A LINE FROM DUBUQUE
TO IOWA CITY TO FAIRFIELD.

ALONG WITH THE THREAT FOR SEVERE WEATHER...HIGH HUMIDITY COMBINED
WITH TEMPERATURES IN THE UPPER 80S TO AROUND 90 DEGREES WILL RESULT
IN VERY UNCOMFORTABLE CONDITIONS. AFTERNOON HEAT INDICES ARE FORECAST
TO TOP OUT BETWEEN 90 AND 100 DEGREES. IF SPENDING TIME OUTDOORS...BE
SURE TO SLOW DOWN...DRINK PLENTY OF FLUIDS AND TAKE FREQUENT BREAKS
IN THE SHADE. ALSO IF SPENDING TIME OUTDOORS...BE SURE TO KEEP AN EYE
TO THE SKY...AND MAKE SURE YOU HAVE A WAY OF MONITORING THE LATEST
WEATHER CONDITIONS.

SPOTTER ACTIVATION WILL LIKELY BE NEEDED BY MID TO LATE AFTERNOON
EAST OF A DUBUQUE TO IOWA CITY TO FAIRFIELD LINE. INTERESTED
INDIVIDUALS SHOULD MONITOR NOAA WEATHER RADIO OR THEIR FAVORITE MEDIA
SOURCE FOR FURTHER UPDATES.

MCCLURE

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
219 PM CDT SUN AUG 06 2000

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

0115 PM    HIAWATHA                  IA   WIND DAMAGE
08/06/00   LINN                           LARGE TREE LIMBS DOWN.
                                          REPORTED BY STORM
                                          SPOTTER.

0115 PM    LOWDEN                    IA   42 MPH TSTM GUST
08/06/00   CEDAR                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

N

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
254 PM CDT SUN AUG 06 2000

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

0228 PM    CEDAR BLUFF               IA   .5 INCH HAIL
08/06/00   CEDAR                          REPORTED BY LAW
                                          ENFORCEMENT OFFICIAL.

N