MESOSCALE PRECIPITATION DISCUSSION 0257
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1131 PM EDT FRI JUN 01 2018

AREAS AFFECTED...SERN NE...NERN KS...SWRN IA...NWRN MO

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

VALID 020330Z - 020930Z

SUMMARY...INCREASING CONVECTION WITH RAINFALL RATES BETWEEN 2-3
IN/HR WILL BE POSSIBLE ACROSS PORTIONS OF SOUTH-CENTRAL TO EASTERN
NE...INTO PORTIONS OF WESTERN IA...NORTHWESTERN MO AND NORTHERN
KS. FLASH FLOODING WILL BE POSSIBLE THROUGH 09Z.

DISCUSSION...RADAR IMAGERY FROM 03Z SHOWED  A FORWARD PROPAGATING
CONVECTIVE LINE EXTENDING FROM NORTHEASTERN TO CENTRAL NE WITH
RADAR ESTIMATED RAINFALL RATES OVER 2 IN/HR EMBEDDED WITHIN THE
LINE. WHILE SOME OF THESE ESTIMATES COULD BE OVERDONE...2.33 IN/HR
WAS REPORTED IN CHAMBERS...SOUTHERN HOLT COUNTY...ENDING 0219Z
WHICH WAS NEAR RADAR ESTIMATES FOR THAT LOCATION AND TIME. THE
SOURCE REGION OF MOISTURE WAS TO THE SOUTH WITH 850 MB DEWPOINTS
FROM 00Z RAOBS OF 17C AND 18C AT DDC AND LMN RESPECTIVELY. 00Z
SOUNDINGS ACROSS THE CENTRAL PLAINS DEPICTED STEEP 700-500 MB
LAPSE RATES BETWEEN 8-9 C/KM...CONTRIBUTING TO MODERATE TO HIGH
CAPE VALUES (3000-5000+ J/KG) FROM KS INTO FAR SOUTHERN NE BUT A
CAPPING INVERSION NEAR 800 MB WAS OBSERVED AT OAX AND TOP.

WATER VAPOR IMAGERY SHOWED THE LEADING EDGE OF A LARGE UPPER LEVEL
TROUGH MOVING INTO THE CENTRAL PLAINS WHICH IS EXPECTED TO COOL
LOW LEVEL TEMPERATURES COINCIDENT WITH INCREASING 850 MB FLOW INTO
THE 50-60 KT RANGE ACROSS KS BY 06Z. A RATHER RAPID INCREASE IN
CONVECTION IS FORECAST IN THE NEXT 1-2 HOURS OVER SOUTH-CENTRAL
NEBRASKA BEFORE MOVING OFF TO THE SOUTH AND EAST. WHILE THERE IS
SOME DRY AIR TO CONTENT WITH...SOME MOISTENING OF THE COLUMN IS
EXPECTED AND FORECAST ALIGNMENT OR NEAR ALIGNMENT OF 850-300 MB
FLOW AND THE ANTICIPATED INFLOW LAYER NEAR 850 MB SHOULD ALLOW FOR
PERIODS OF TRAINING ALONG THE SOUTHERN EDGE OF THE DEVELOPING MCS.
THE RESULT IS EXPECTED TO BE RAINFALL RATES OF 2-3 IN/HR AT TIMES
ALONG WITH 6 HOUR RAINFALL TOTALS OF 3-6 INCHES WHICH COULD CAUSE
RAPID RUNOFF ON TOP OF 3 HOUR FFG VALUES OF 2-3 INCHES DESPITE
RELATIVELY DRY ANTECEDENT CONDITIONS.

OTTO

ATTN...WFO...DMX...EAX...GID...GLD...ICT...LBF...OAX...TOP...

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

LAT...LON   42169591 42159510 41969417 41619368 41059340
            40079364 39339489 38929731 39879970 41169979
            41769856 42099691