MESOSCALE PRECIPITATION DISCUSSION 0221
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
742 PM EDT TUE MAY 16 2017

AREAS AFFECTED...SOUTHERN & SOUTHEAST NEB...NORTH CENTRAL
KS...SOUTHWESTERN IA

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

VALID 162345Z - 170345Z

SUMMARY...E-W LINE OF SLOW MOVING CONVECTION WITH POTENTIAL FOR
TRAINING/MERGERS CAPABLE OF INDUCING LOCALIZED FF CONDITIONS
THROUGH THE LATE EVENING HOURS.

DISCUSSION...GOES-EAST AND EXP. GOES-16 WV DENOTES STRONG UPPER
LEVEL LOW LIFTING NORTH ACROSS NM WITH STRONG 110KT JET NOSING
ACROSS THE TX PANHANDLE INTO W OK ATTM.  MORE SUBTLY A SMALLER
SCALE WAVE IS LIFTING NORTH-NORTH EAST ACROSS W KS WITH BETTER
DEFINED SHORTWAVE RIDGING ACROSS NEB...DEPICTING THE ENTRANCE TO
CONVECTIVELY ENHANCED JET THAT WILL CONTINUE TO LIFT NORTH ACROSS
NEB PROVIDING AN EXCELLENT DUAL JET REGIME FOR UPPER LEVEL
DIVERGENCE ACROSS S NEB/N KS THROUGH THE EVENING.  THIS COUPLET IS
ALSO REFLECTED IN THE LOWER LEVELS PARTICULARLY AT 850MB WHERE A
ENE TROF EXTENDS FROM E CO ACROSS NW KS INTO SE NEB/W IA.  BROAD
SOUTHERLY LLJ CURRENTLY AT 35-40KTS PER VWP NETWORK INTERSECTS THE
TROF PROVIDING DEEP MST CONVERGENCE TO SPARK THE LONG LINE THAT
HAS SOME EMBEDDED CELLS ROOTED A BIT DEEPER TOWARD THE SURFACE
PARTICULARLY IN PROXIMITY OF SFC FRONT.  CELLS CONTINUE TO UNZIP
WEST ALONG THE FRONT TOWARD THE INTERSECTION OF THE RETROGRADING
DRY LINE OVER NW KS (DEPICTED WELL IN REGION RADAR
REFLECTIVITY)...THE FURTHER WEST ALONG THE LINE THE GREATER
POTENTIAL FOR CELLS TO TRACK THROUGH AN AREA OF LOWERED FFG VALUES
ACROSS NW KS AND SOUTH CENTRAL NEB FROM LAST EVENINGS 1-2" OF RAIN.

AS THE MAIN HEIGHT FALLS ADVANCE OUT OF N NM/SW CO...THE 850MB LOW
WILL CONTINUE TO WIND UP AND INCREASE LLJ TO 50-60KTS ACROSS KS TO
NEB.  ADDITIONALLY ALLOWING CLOUD BEARING FLOW TO ORIENT MORE
FAVORABLY ALONG THE 850 TROF/FRONTAL BOUNDARY ACROSS NEB PROVIDING
A TRAINING CORRIDOR.   18Z NAM-CONEST AND RECENT HRRR RUNS APPEAR
TO BE HANDLING THE ONGOING EVOLUTION WELL AND SUPPORT AN AREA OF
2-3" WITH ISOLATED 4" TOTALS THROUGH 04Z MAINLY ACROSS S CENTRAL
AND SE NEBRASKA INTO SW IA.  FFG VALUES ARE A BIT HIGHER THROUGH
THIS AREA THAN FURTHER WEST BUT GIVEN THIS POTENTIAL...THERE
REMAINS A LOCALIZED THREAT FOR FLASH FLOODING THROUGH THE LATE
EVENING/EARLY OVERNIGHT HOURS.

GALLINA

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

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

LAT...LON   42259482 41839415 41109483 39889728 39549941
            39810044 40540011 41009815 41889600