MESOSCALE PRECIPITATION DISCUSSION 0289
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1201 AM EDT MON JUN 11 2018

AREAS AFFECTED...CENTRAL IOWA...FAR NORTHERN MISSOURI

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

VALID 110400Z - 111000Z

SUMMARY...THUNDERSTORMS ARE LIKELY TO PERSIST THROUGH MUCH OF THE
NIGHT OVER CENTRAL IOWA. THIS SHOULD LEAD TO POCKETS OF VERY HEAVY
RAINFALL AND ASSOCIATED FLASH FLOODING. RAIN RATES MAY REACH 2
IN/HR AND RAINFALL TOTALS MAY EXCEED 5 INCHES ON A LOCALIZED BASIS.

DISCUSSION...OVER THE PAST FEW HOURS...CONVECTION HAS GRADUALLY
BECOME MORE WIDESPREAD OVER CENTRAL IOWA AND WAS ANCHORED ROUGHLY
IN THE SAME LOCATION OVER THAT TIME FRAME. CONVECTIVE INITIATION
OCCURRED IN A BROAD REGION OF LOW-LEVEL CONFLUENCE...AND ON THE
NORTHEASTERN PERIPHERY OF THE PLAINS LOW-LEVEL JET. IT ALSO
OCCURRED ON THE EDGE OF A PROMINENT EML PLUME SITUATED OVER THE
PLAINS...WITH THE +12C ISOTHERM AT 700MB LOCATED JUST WEST OF
ONGOING CONVECTION. THE APPROXIMATE POSITION OF THESE FEATURES
LOOKS LIKELY TO BE FAIRLY STABLE THROUGH THE NEXT SEVERAL
HOURS...WHICH SHOULD CONTINUE TO ANCHOR THE CONVECTION IN PLACE
OVER CENTRAL IOWA IN A REGION OF MODERATE INSTABILITY (MUCAPE
AROUND 1500-2000 J/KG) AND DEEP MOISTURE (PWATS AROUND 1.7 INCHES
PER RAP ANALYSIS).

ALMOST ALL HI-RES MODELS INITIALIZED AT 00Z HAVE SOME SIGNAL FOR
HEAVY RAINFALL IN THIS REGION...AND THE 00Z HREF PROBABILITY OF AT
LEAST 5 INCHES OF RAIN BY 12Z IS AS HIGH AS 30 PERCENT IN SOME
AREAS. THE SOMEWHAT SCATTERED NATURE OF INDIVIDUAL CELLS AND
CONVECTIVE CLUSTERS MAY PREVENT WIDESPREAD TOTALS OF THAT
NATURE...BUT IT SEEMS REASONABLE THAT LOCALIZED AREAS COULD EXCEED
5 INCHES OF RAINFALL. RAIN RATES MAY REACH 2 IN/HR GIVEN FAVORABLE
CELL MERGERS. KDMX DUAL POL ESTIMATES ARE ALREADY AS HIGH AS 1.5
IN/HR IN SOME AREAS...AND AS CONVECTIVE CLUSTERS GROW AND
MATURE...THE PEAK RAIN RATES ARE LIKELY TO INCREASE SLIGHTLY.

GIVEN THE EXPECTED PERSISTENCE OF CONVECTION OVER CENTRAL IOWA AND
EXPECTED HEAVY RAIN RATES...FLASH FLOODING APPEARS LIKELY.

LAMERS

ATTN...WFO...DMX...DVN...EAX...FSD...LSX...

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

LAT...LON   43239393 41889304 41279259 40539217 40019250
            40149344 40669409 41369463 42579511 43219470