Graphic for MPD #0429
MESOSCALE PRECIPITATION DISCUSSION 0429
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
904 AM EDT SUN JUL 02 2017

AREAS AFFECTED...SOUTHEAST NEBRASKA

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

VALID 021305Z - 021615Z

SUMMARY...STRONG WAA REGIME WITH BACKBUILDING AND TRAINING POSE
SHORT-TERM FLASH FLOOD RISK.

DISCUSSION...EXPERIMENTAL GOES-16 WV LOOP SHOWS A LOCALIZED IDEAL
LOCATION FOR CONVECTIVE DEVELOPMENT.  FAIRLY CONCENTRIC WAVE OVER
THE GREAT LAKES IS EQUALED BY THE DIPOLE ANTICYCLONE ACROSS NW
IA/SE SD WITH STRIPE OF ENHANCED MOISTURE/COOLER BRIGHTNESS TEMPS
WITH JET ACROSS MN.  FURTHER SOUTH STRONGER THAN EXPECTED MCS
SHOWS EXCELLENT OUTFLOW PATTERN WITH CONVECTIVELY ENHANCED
ANTICYCLONIC CURVED JET STREAK DENOTED BY TRANSVERSE BANDING
SCRAPING THE PERIPHERY OF THE AREA OF CONCERN.  BOTH FLOW REGIMES
COMBINED SUPPORT STRONG UPSCALE UPPER LEVEL EVACUATION TO MAINTAIN
CONVECTION.  ADDITIONALLY THIS SUPPORTS STRONGER BUT ALSO VEERING
LOW LEVEL FLOW/WARM AIR ADVECTION FORCING.  CURRENT DUAL POL RADAR
MOSAIC SUPPORTS THIS WITH BACKBUILDING/INFLOW BANDS STARTING TO
INCREASE OVER THE GRAND ISLAND VICINITY.  ADDITIONALLY WITH THE
LOW LEVEL MEAN WEAK NORTHWESTERLY CLOUD BEARING ENVIRONMENT
SUPPORTS SLOW SOUTHEASTWARD MOVEMENT.  MOISTURE DEPTH IS ALSO
INCREASING AS CONVECTION IN CENTRAL KS IS MOISTENING THE PROFILE
TO ALLOW FOR SOME INCREASED RAINFALL EFFICIENCY WITH TPWS NOW
APPROACHING 1.5" AND SOLID MST FLUX SUPPORTING RAIN RATES AOA
2.0".  GIVEN FFG VALUES BELOW 2"/1HR AND 2.5"/3 HRS THERE IS A
FLASH FLOODING RISK.

THOUGH SOME COLD POOL GENERATION IS OCCURRING ALLOWING FOR THE
LINE TO BOW SOUTHWARD ACROSS S SEWARD/W LANCASTER COUNTY... THE
UPSTREAM REDEVELOPMENT WILL CONTINUE TO POSE AN SHORT-TERM
ENVIRONMENT FOR TRAINING ACROSS YORK/SALINE COUNTIES FOR AT LEAST
THE NEXT FEW HOURS (UNTIL JET STREAK FORCING PASSES).  A GOOD
HARBINGER OF TIMING OF WEAKENING WILL LIKELY BE ABOUT A 30 MINUTE
TO 1 HOUR DELAY AS THE WAA CONVECTION IN KS BEGINS TO FADE...AS
THE THE OUTFLOW JET STREAK FORCING PASSES. 

TO BE EXPECTED...HI-RES GUIDANCE IS NOT PERFORMING WELL THOUGH THE
NSSL-WRF MAY HAVE THE BEST IDEA...THE FORWARD (SOUTHEAST)
PROPAGATION IS LIKELY A BIT OVER DONE AS THERE IS LIMITED VEERING
DENOTED AND IS MISSING THE UPPER LEVEL OUTFLOW JET
STRENGTH/CURVATURE.   ADDITIONALLY EXTREME SE NEB/NE KS ARE
REMARKABLY DRY AND GIVEN DEPARTURE FROM BEST INFLOW/MST...CELLS
WOULD LIKELY RAPIDLY DIE INTO THIS VICINITY.

GALLINA

ATTN...WFO...GID...OAX...

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

LAT...LON   41579770 41499674 40889588 40309595 40199645
            40189699 40639814 41189815


Last Updated: 904 AM EDT SUN JUL 02 2017