MESOSCALE PRECIPITATION DISCUSSION 0389
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
159 AM EDT TUE JUL 03 2018

AREAS AFFECTED...CENTRAL AND NORTHEASTERN SD...

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 030600Z - 031100Z

SUMMARY...STATIONARY CONVECTIVE COMPLEX

DISCUSSION...GOES-16 10.3UM LOOP DEPICTS A CLASSIC ENHANCED V
SIGNATURE WITH IR TOPS REMAINING COLD AT NEAR -70C WITH UPSTREAM
WEDGE STATIONARY OVER N HYDE COUNTY.  LLJ CONTINUES TO STRENGTHEN
WITH 40-45KT 850 FLOW DIRECTED FROM SW TO THE UPSTREAM EDGE OF THE
COMPLEX...AND GOES-CAPE AND TPW IMAGERY SHOWING THE
MST/INSTABILITY AXIS DIRECTED ALONG THE JET AXIS FROM S CENTRAL SD
INTO THE COMPLEX WITH HIGHER VALUES OF INSTABILITY REMAINING
UPSTREAM IN THE 2500-3000 J/KG RANGE.  MOISTURE FLUX OF SFC TDS IN
THE UPPER 60S/LOW 70S AND 17-18C 850MB Q-AXIS NOSE IDEALLY ALIGNED
TO THE DEVELOPMENT REGION.  05Z ANALYSIS AND RADAR SUITE ALSO
DEPICTS STRENGTHENING MESO HIGH TO THE EAST FURTHER STRENGTHENING
MST CONVERGENCE AND UPGLIDE OVER OUTFLOW THAT IS STARTING TO
ORIENT ORTHOGONAL TO THE LLJ AXIS.  THE COMBINATION WILL CONTINUE
TO ALLOW FOR STRONG ISENTROPIC ASCENT OF THE DEEP
MOISTURE/INSTABILITY AXIS ACROSS CENTRAL AND EAST CENTRAL SD
THROUGH A LARGE PORTION OF THE OVERNIGHT HOURS. 

REGIONAL RADARS ARE ESTIMATING RAIN RATES IN EXCESS OF 3"/HR AND
GIVEN THE SMOKE/AEROSOL NUCLEATION FOR HIGHER DROPLET DENSITY THIS
SEEMS TO BE A GOOD ESTIMATE WITHOUT ANY CONFIRMATION FROM LOCAL
OBSERVATIONS.  GIVEN THE LIKELY DURATION OF THE SAME ORIENTATION
WITH SLIGHT INCREASE OF LLJ FLOW TO 50KTS...IT IS A GOOD
POSSIBILITY THAT THERE WILL BE VERY LIMITED MOTION (5 KTS OR LESS
TO SSW NEAR CENTER OF THE CLUSTER). THE DURATION SEEMS TO BE THE
GREATEST UNCERTAINTY AT THIS TIME...BUT GIVEN TRACK OF THE LEAD
COMPACT SHORTWAVE CURRENTLY CROSSING INTO SE ND AND STRONG
UPSTREAM SHORTWAVE/MCV IN MT FLOW SHOULD BE FAIRLY STATIC IN
DIRECTION/STRENGTH THROUGH 10-11Z. AS SUCH AN ADDITIONAL 4-6" SEEM
PLAUSIBLE WITH EVEN VALUES TO 8" POSSIBLE IN SOME LOCATIONS
LEADING TO POTENTIAL LIFE THREATENING FLASH FLOODING THROUGH THE
REMAINDER OF THE OVERNIGHT. 

GALLINA

ATTN...WFO...ABR...FSD...

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

LAT...LON   45499818 45189710 44759672 44289723 44259832
            44319946 44340027 44550061 45210031 45459926