Severe Thunderstorm Warning 30, NWS Quad Cities, IA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
755 PM CDT WED MAY 8 1996

SUBSIDENCE IN THE WAKE OF THE MCS THIS MORNING CLEANED OUT THE SKIES
ACROSS MUCH OF IOWA TODAY.  SATELLITE SHOWS THIS WELL AND NOW SHOWS THE
BEGININGS OF THE NEXT MCS ACROSS KANSAS/NEBRASKA.  LATHROP AND FAIRBURY
PROFILERS SHOW THE LOW LEVEL WINDS PICKING UP.  00Z HAND ANALYSIS AND
MAPS FRONTOGENESIS FUNCTION SHOW FRONT EXTENDING FROM KANSAS ACROSS
SOUTHWEST IOWA TO NORTHERN ILLINOIS.

12Z MODELS PUSHED THE FRONT NORTH AND THEIR 12 HOUR FORECASTS VERIFIED
WELL WITH CURRENT HAND ANALYSIS.  STRONG QG FORCING SHOWN ACROSS
FORECAST AREA BY 12Z AND PCPN MAX WILL BE CENTERED OVER I80.  THIS MORE
NORTHERLY TRACK WILL KEEP THE HEAVIEST RAINS OUT OF THE SAME TRACK AS
LAST NIGHT... BUT STILL CONCERNED ABOUT FLOODING THERE AND HERE.  PWS
SIMILAR TO LAST NIGHT ONLY FURTHER NORTH.  TIMING SHOULD BE AFTER 8 OR
9Z.

FFG VALUES SIMILAR ACROSS THE NORTHERN HALF OF THE FORECAST AREA TO
WHAT WE SAW LAST NIGHT... AND WITH SIMILAR RAINFALL AMOUNTS POSSIBLE...
WONDER ABOUT NEED FOR FLASH FLOOD WATCH MOST AREAS.  CURRENT WATCH
ACROSS ILLINOIS IS GOOD AND JUST LOOK TO EXPAND IT NORTH TO I80.  AM
MOST CONCERNED ACROSS SOUTHEAST IOWA WHERE HEAVY RAINS FELL LAST NIGHT.
RECOMEND THAT AT THE VERY LEAST IOWA ZONES SOUTH OF HIGHWAY 34 BE PLACED
IN A FLASH FLOOD WATCH.

CID 58/++  DBQ 55/++  MLI 59/++  BRL 63/90

HIRSCH

IAZ030-040>042-051>054-063>068-076>078-087>089-098-099-ILZ001-
002-007-009-015>018-024>026-034-035-091200-

SIGNIFICANT WEATHER OUTLOOK FOR EASTERN IOWA AND NORTHWEST ILLINOIS
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
914 PM CDT WED MAY 8 1996

...HEAVY RAINFALL POSSIBLE AGAIN ON THURSDAY MORNING...

A FRONT ACROSS SOUTHWESTERN IOWA AND NORTHERN ILLINOIS WILL BRING
ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS TO THE AREA.  ABUNDANT
MOISTURE RACING OVER THE FRONT HAS ALREADY INITIATED A LARGE COMPLEX OF
THUNDERSTORMS ACROSS EASTERN NEBRASKA.  THESE THUNDERSTORMS WILL TRACK
EASTWARD ALONG THE A FRONT ACROSS IOWA... REACHING EASTERN IOWA AND
NORTHWEST ILLINOIS EARLY THURSDAY.

MOST OF THE SEVERE WEATHER ASSOCIATED WITH THIS COMPLEX IS EXPECTED TO
OCCUR THIS EVENING ACROSS NEBRASKA AND WESTERN IOWA.  THE MAIN THREAT
FOR EASTERN IOWA AND NORTHWEST ILLINOIS WILL BE LOCALLY HEAVY RAINFALL
THURSDAY MORNING.

RAINFALL AMOUNTS OF 1 TO 2 INCHES WITH LOCAL AMOUNTS NEAR 3 INCHES CAN
BE EXPECTED ALONG I80 OVERNIGHT.  HEAVY RAINFALL IN A SHORT PERIOD OF
TIME COULD PUSH SOME LOCATIONS INTO FLASH FLOODING SITUATIONS.

AREAS ALONG AND SOUTH OF HIGHWAY 34 RECEIVED BETWEEN ONE AND FOUR
INCHES OF RAINFALL EARLY WEDNESDAY MORNING AND RAINFALL IN EXCESS OF AN
INCH COULD CAUSE ADDITIONAL FLOODING.  FOR THIS REASON A FLASH FLOOD
WATCH IS IN EFFECT FOR THE ILLINOIS COUNTIES OF HENDERSON... WARREN...
HANCOCK... AND MC DONOUGH.

AGAIN AT THIS TIME SEVERE THUNDERSTORMS ARE NOT EXECTED IN OUR AREA...
HOWEVER THE POTENTIAL FOR VERY HEAVY RAINFALL IS JUST AS SERIOUS A
THREAT.

STAY TUNED FOR UPDATES ON THIS POTENTIALLY HAZARDOUS WEATHER
SITUATION.

HIRSCH