MESOSCALE PRECIPITATION DISCUSSION 0383
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
213 AM EDT SUN JUL 01 2018

AREAS AFFECTED...NORTHEASTERN KS/NORTHWESTERN NEB/NORTHWESTERN
MO/IA...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 010613Z - 010958Z

SUMMARY...REAGGRAVATION OF FLASH FLOOD CONCERNS ARE LIKELY IN
ADVANCE OF AN APPROACHING MCS. OBSERVED HOURLY RAINFALL RATES
WITHIN THIS LINE HAVE BEEN AROUND 1 TO 1.50 INCHES PER MESONET
DATA. ADDING THIS ON TOP OF ALREADY SATURATED SOILS WILL ENHANCE
THE THREAT FOR FLASH FLOODING.

DISCUSSION...MULTIPLE HOURS OF HEAVY RAINFALL WITH TRAINING
ELEMENTS LEFT PORTIONS OF CENTRAL IA...PARTICULARLY THE WESTERN
SUBURBS OF DES MOINES WITH FLOODING ISSUES. LOCAL REPORTS ACROSS
POLK COUNTY HAVE GENERALLY BEEN IN THE 5 TO 7 INCH RANGE WITH EVEN
A 10 INCH ESTIMATE. WHILE THE UPSTREAM ACTIVITY HAS REMAINED
PROGRESSIVE AND SHOWN EPISODIC PERIODS OF WEAKENING...ANY
ADDITIONAL RAINFALL TONIGHT WILL LIKELY AGGRAVATE THE FLOODING
ISSUES AND ANY RELIEF EFFORTS. THUS...WILL MAINTAIN A FLASH
FLOODING LIKELY DESIGNATION INTO THE EARLY MORNING HOURS.

ASSISTED BY THE STRENGTHENING OF A NOCTURNAL LOW-LEVEL JET (35 TO
40 KNOTS PER VWP DATA ACROSS KANSAS CITY)...A FAIRLY HEALTHY MCS
CONTINUES TO RACE EASTWARD TOWARD OMAHA NEB AT ROUGHLY 40 MPH.
WOULD EXPECT GRADUAL WEAKENING AS THIS SYSTEM NEARS THE NEB/IA
BORDER MUCAPE VALUES MAXIMIZING IN THE 500 TO 1000 J/KG RANGE.
THIS WOULD SUGGEST THE MENTIONED RATES OF 1 TO 1.50 INCHES MAY
COME DOWN A BIT IN THE NEXT FEW HOURS. HOWEVER...THERE IS A
SEPARATE BAND OF CONVECTION LIFTING INTO SOUTHWESTERN IA WHICH
WOULD ALLOW TWO ROUNDS OF PRECIPITATION TO MOVE THROUGH CENTRAL IA.

DURING THE NEXT 4 HOURS...ALL OF THE 00Z CAMS FAVOR RAPID
DISSIPATION OF THIS LINE OF THUNDERSTORMS. THE SOUTHERN EXTENT OF
THIS MCS HAS SHOWN A MARKED WARMING IN CLOUD TOPS BUT HEALTHY
CONVECTION DOES REMAIN ACROSS EAST-CENTRAL NEB. PERHAPS THE MODELS
ARE A LITTLE TOO QUICK TO WEAKEN THIS COMPLEX. WHILE RAINFALL
RATES SHOULD COME DOWN CONSIDERABLY...THE ANTECEDENT CONDITIONS
STILL WARRANT A THREAT FOR FLASH FLOODING.



RUBIN-OSTER

ATTN...WFO...ARX...DMX...DVN...EAX...OAX...TOP...

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

LAT...LON   42929389 42929292 42609238 42059229 41499260
            40779326 39859419 39149477 39179567 39979605
            40989597 42339521