MESOSCALE PRECIPITATION DISCUSSION 0548...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1234 AM EDT FRI AUG 12 2016
 
CORRECTED FOR TRANSLATED MPD AREA A BIT FARTHER WEST

AREAS AFFECTED...EXTREME NORTHEASTERN KS/SOUTHERN TO SOUTHEASTERN
IA/NORTHERN MO/NORTHWESTERN IL... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 120424Z - 120839Z
 
SUMMARY...AN EXPANSIVE COMPLEX OF SHOWERS/THUNDERSTORMS CONTINUES
TO IMPACT LARGE PORTIONS OF THE MIDDLE MS VALLEY. RECENT REPORTS
HAVE INDICATED 1 TO 2 INCH HOURLY RATES HAVE BEEN COMMONPLACE
ACROSS SECTIONS OF IA. EXPECT THE CONVECTION TO REMAIN FAIRLY
ORGANIZED OVERNIGHT GIVEN THE COMBINATION OF AMPLE TROPOSPHERIC
MOISTURE AND STRENGTHENING NOCTURNAL LLJ.

DISCUSSION...RECENT IR SATELLITE IMAGERY INDICATED THE COLDEST
CLOUD TOPS WERE LOCATED OVER EASTERN IA WHICH REMAINS WITHIN A
VERY MOIST/HIGHLY DIFFLUENT ATMOSPHERE. AN ADDITIONAL AREA OF
CONVECTION HAS FIRED ALONG A NORTH/SOUTH AXIS STRETCHING FROM
SOUTHWESTERN IA DOWN INTO EASTERN KS. IN BETWEEN THESE TWO REGIONS
THE CONVECTIVE ACTIVITY HAS WEAKENED AND BECOME MORE OUTFLOW
DOMINANT IN NATURE. OVERALL...THE BIGGEST THREAT AREA CONTINUES TO
BE OVER EASTERN IA INTO NORTHWESTERN IL WHERE THE COMPLEX HAS BEEN
SLOWER MOVING WITH WEST-EAST TRAINING NOTED IN THE QUAD CITIES
LOCAL RADAR. GIVEN SURFACE DEW POINTS IN THE UPPER 70S AT THIS
TIME...THE AIR MASS REMAINS QUITE MOIST AND VERY UNSTABLE WITH THE
RAP OBJECTIVE ANALYSIS SUGGESTING MUCAPE VALUES IN THE 2000 TO
4000 J/KG RANGE IN ADVANCE OF THE WAVY LINE. ADDITIONALLY
CONCERNING IS THE FORECAST CORFIDI VECTORS BEING NEGLIGIBLE AT
TIMES AS THE SOUTHWESTERN LLJ IS NEARLY EQUAL/OPPOSITE OF THE MEAN
CLOUD-BEARING FLOW DURING THE NEXT 3 TO 4 HOURS. THUS...FLASH
FLOODING IS MOST LIKELY OVER EASTERN IA/NORTHWESTERN IL GIVEN THIS
COUPLED WITH RECENT RADAR/SATELLITE TRENDS.

THERE ARE A FEW MODELS WHICH SEEMED TO BE PERFORMING BETTER THAN
OTHERS WHICH INCLUDES THE 12Z HRW-ARW AS WELL AS THE 02Z/01Z
HRRR-OPERATIONAL RUNS. THESE BOTH FAVOR A 6-HOUR RAINFALL MAXIMA
THROUGH 09Z GENERALLY OVER EASTERN IA INTO NORTHWESTERN/NORTHERN
IL. WILL ALLOW FOR A BRIEF TEMPORAL OVERLAP OF MPD #0547 TO THIS
ONE GIVEN HEAVY RAINFALL HAS STARTED TO LEAVE THE EASTERN EXTENT
OF THE PRECEDING MPD.


RUBIN-OSTER

ATTN...WFO...DMX...DVN...EAX...ILX...LOT...LSX...OAX...TOP...

ATTN...RFC...MBRFC...NCRFC...

LAT...LON   42488961 42348865 41508825 40858862 40428989 
            40039126 39279289 39309410 39589490 39979539 
            40789526 41209460 41489355 41719277 42339126