MESOSCALE PRECIPITATION DISCUSSION 0117...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
336 AM EDT SAT APR 15 2017

CORRECTED FOR INTERSTATE NUMBER

AREAS AFFECTED...EASTERN NEB/WESTERN IA...

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

VALID 150512Z - 150857Z

SUMMARY...ORGANIZED CONVECTION CONTINUES NORTH OF I-80 ACROSS
SECTIONS OF EAST-CENTRAL NEB. WHILE PRIMARILY A HAIL
PRODUCER...GENERAL EAST-WEST TRAINING SUGGESTS THERE IS AN
INHERENT FLASH FLOOD RISK AS WELL. THIS SHOULD REMAIN AN ISSUE AS
LONG AS THE THUNDERSTORM COMPLEX STAYS INTACT.

DISCUSSION...A PAIR OF SHORTWAVES NOTED IN WATER VAPOR IMAGERY
HAVE BEEN FOCI FOR ACTIVE NOCTURNAL CONVECTION. THE LEAD FEATURE
RESIDES IN A WELL-ESTABLISHED KINEMATIC AND THERMODYNAMIC
ENVIRONMENT WITH MUCH GREATER BUOYANCY AND INTENSE LOW-LEVEL WARM
ADVECTION. RECENT VAD-WIND PROFILER DATA ACROSS EASTERN KS/NEB
INDICATE 925-850 MB WINDS HAVE REMAINED IN THE 55 TO 65 KNOT RANGE
THROUGHOUT THE LATE EVENING HOURS. WHILE SOME OF THE INSTABILITY
HAS BEEN ERODED DUE TO COOLING OF THE BOUNDARY LAYER AND MASS
OVERTURNING OF THE TROPOSPHERE...APPRECIABLE CAPES STILL REMAIN
BASED ON THE LATEST RAP OBJECTIVE ANALYSIS.

THE CURRENT RADAR IMAGERY HAS FINALLY SHOWN SOME SOUTHWARD BOWING
OF THIS EAST-WEST LINE WHICH INDICATES THERE HAS BEEN SOME COLD
POOL GENERATION. HOWEVER...FURTHER UPSTREAM...RENEWED CB TOWERS
ARE EVIDENT BACK TOWARD CUSTER COUNTY IN CENTRAL NEB AS CLOUD TOPS
CONTINUE TO COOL OVER THIS REGION. THE WILD CARD REMAINS FARTHER
WEST WITH HOW THE TRAILING SHORTWAVE WILL INTERACT WITH ITS
COUNTERPART DOWNSTREAM. MANY CAM SOLUTIONS SHOW A MORE WIDESPREAD
EVENT POSSIBLY UNFOLDING ALTHOUGH THE WESTERN NEB CONVECTION HAS
NOT REALLY BEGUN TO TAKE OFF YET. THE LATEST
HRRR/EXPERIMENTAL-HRRR SEEM TO BE THE BEST BETS WHILE THE 00Z
PARALLEL HRW-ARW/HRW-NMM-B GIVING TOO MUCH CREDIT TO THE WESTERN
NEB SHORTWAVE.

RUBIN-OSTER

ATTN...WFO...DMX...FSD...GID...LBF...OAX...

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

LAT...LON   43279655 43229605 42679556 41999533 41409573
            41069651 40899808 41209945 41549977 41879980
            42089934 42479822 42849731 43069686