683
AWUS01 KWNH 050056
FFGMPD
SDZ000-050600-
MESOSCALE PRECIPITATION DISCUSSION 0319
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
855 PM EDT THU JUN 04 2026
AREAS AFFECTED...CENTRAL TO EASTERN SOUTH DAKOTA...
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 050055Z - 050600Z
SUMMARY...EXPANDING CLUSTER OVER AREAS SATURATED LAST EVENING,
BEFORE APPROACH OF MAIN SHORTWAVE/CONVECTIVE LINE AFTER DARK.
SPOTS OF 2-3" OVER WET GROUNDS POSE LOCALIZED FLASH FLOODING
ISSUE.
DISCUSSION...00Z SURFACE ANALYSIS DENOTES A SURFACE WAVE SOUTHEAST
OF PIERRE WITH STATIONARY FRONT EXTENDING NORTHEAST GENERALLY
CONNECTED/INFLUENCE BY A FAST MOVING MID-LEVEL SHORTWAVE CROSSING
INTO NW MN; WHILE THE UPSTREAM PORTION OF THE FRONT ANGLES MORE
WESTWARD INTO SW SD BEFORE THE APPROACH OF THE MAIN
HEIGHT-FALLS/SHORTWAVE THAT IS DIRECTING FAST MOVING
STRONGER/SEVERE THUNDERSTORMS OUT OF THE BLACK HILLS. AS SUCH,
SURFACE TO BOUNDARY LAYER FLOW HAS BACKED AND INCREASED WITH A
POCKET OF ENHANCED LOW LEVEL MOISTURE WITH TDS IN THE MID TO UPPER
60S AND POOL OF 1.25-1.5" TOTAL PWATS CONTINUE TO FLUX/CONVERGE TO
INCREASE RAINFALL EFFICIENCY. RAP ANALYSIS SHOWS POOL OF
CONDITIONALLY UNSTABLE (BUT WEAKLY CAPPED) MLCAPE OF 2000-2500
J/KG ALONG THE FRONT INTO CENTRAL SD. THE OVERALL CONVERGENCE
WITH INITIAL WEAKENING CONVECTION/OUTFLOW IMPINGING ON THE FRONT
RESULTED IN RAPID CONVECTIVE DEVELOPMENT WITH 10.3UM EIR TOPS
COOLING PAST -65C ACROSS HAND INTO BEADLE COUNTY. GIVEN THIS
RATES OF 1.5"/HR WILL STEADILY INCREASE TO 2"/HR WITH TIME.
RADAR AND EIR SHOW FURTHER DOWNSTREAM CONVECTIVE DEVELOPMENT
EXPANDING THE OVERALL WIDTH OF THE DOWNDRAFTS INCREASING RESIDENCY
TIME IN THE GENERALLY WEST TO EAST FLOW; WITH AN ADDITIONAL ROUND
STILL UPSTREAM. COMBINE THIS WILL TRAVERSING AREAS HIT OVERNIGHT
YESTERDAY AND LIGHTER/MODERATE ACTIVITY THIS AFTERNOON. A LINE OF
ADDITIONAL 2-3" TOTAL (IN AREAS OF 2-4") SHOULD BE HARDER TO
INFILTRATE AND RESULT IN INCREASED RUN-OFF AND POTENTIAL FOR
INDUCING LOCALIZED FLASH FLOODING.
GALLINA
..PLEASE SEE WWW.WPC.NCEP.NOAA.GOV FOR GRAPHIC PRODUCT
ATTN...WFO...ABR...FSD...UNR...
ATTN...RFC...KRF...MSR...NWC...
LAT...LON 45099748 44949668 44569647 44079679 43669791
43479872 43419914 43310029 43330103 43560137
44020126 44550013 44719964 45019894
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