Graphic for MPD #0476

MESOSCALE PRECIPITATION DISCUSSION 0476
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
717 PM EDT WED JUL 12 2017

AREAS AFFECTED...NORTHEAST KS & THE MO/IA BORDER

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 122317Z - 130517Z

SUMMARY...CONVECTION IS BREAKING THE CAPPING INVERSION NEAR THE
KS/MO/NE BORDER INTERSECTION.  HOURLY RAIN RATES TO 2.5" WITH
LOCAL AMOUNTS TO 4" ARE POSSIBLE.

DISCUSSION...RECENT RADAR/SATELLITE IMAGERY SHOWS A NEW BATCH OF
CONVECTION ACROSS NORTHEAST KS.  A SHORTWAVE/OLD MCV MOVING INTO
NORTHWEST IA APPEARS TO BE HELPING AID DIVERGENCE ALOFT. 
PRECIPITABLE WATER VALUES ARE NEAR 2".  INSTABILITY IS SIGNIFICANT
HERE, WITH MLCAPE VALUES OF 2500-4500 J/KG AND MU CAPE VALUES OF
4000-5000 J/KG.  CIN IS FINALLY ERODING IN THIS AREA PER SPC
MESOANALYSES.  INFLOW AT 850 HPA IS SOUTHWEST AT 20 KTS, NEAR THE
MAGNITUDE OF THE MEAN 850-400 HPA WIND.  EFFECTIVE BULK SHEAR IS
~30 KTS, WHICH IS HELPING TO ORGANIZE THE ACTIVITY INTO A SHORT
BAND.

MOST OF THE 12Z MESOSCALE GUIDANCE HAS FAILED IN THIS REGION.  THE
12Z WRF NSSL, 18Z CANADIAN REGIONAL, AND RECENT RAP/HRRR RUNS
APPEAR TO HAVE SOME CONCEPT OF WHAT IS EXPECTED HERE.  ALTHOUGH
CIN IS EXPECTED TO SET BACK IN DURING THE NEXT FEW HOURS, THE
DEGREE OF CONVECTIVE ELEVATION OVER THE SURFACE BOUNDARY IS LIKELY
TO BE MINIMAL DUE TO THE MAGNITUDE OF INSTABILITY FORECAST OVER
THE NEXT SEVERAL HOURS.  INCREASING LOW-LEVEL INFLOW WITH TIME
IMPLIES THE POSSIBILITY OF CONVECTIVE BACKBUILDING, WHILE THE NEAR
UNIDIRECTIONAL FLOW WITH HEIGHT SUPPORTS TRAINING BANDS.  MOTION
TO THE EAST AT 20 KTS IS EXPECTED.  HOURLY RAIN RATES UP TO 2.5",
WITH LOCAL AMOUNTS TO 4", APPEAR POSSIBLE.

ROTH

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

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

LAT...LON   41569128 41289038 40219052 39499177 39229352
            39329723 40839379


Last Updated: 717 PM EDT WED JUL 12 2017