MESOSCALE PRECIPITATION DISCUSSION 0445
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
648 PM EDT SAT JUL 09 2016
AREAS AFFECTED...EASTERN ND & NORTHWEST MN
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE
VALID 092247Z - 100247Z
SUMMARY...THUNDERSTORMS ARE EXPANDING IN COVERAGE AND SHOWING SOME
SIGNS OF BACKBUILDING. HOURLY RAIN RATES UP TO 2", WITH LOCAL
AMOUNTS IN THE 2-4", COULD LEAD TO FLASH FLOODING.
DISCUSSION...A BROADENING AREA OF THUNDERSTORMS WITH SIGNS OF
BACKBUILDING HAS BEEN DEVELOPING ACROSS EASTERN ND, JUST TO THE
EAST OF A WEAK FRONTAL WAVE. TO THE NORTH, A MORE ORGANIZED
THUNDERSTORM COMPLEX WITH HIGHER RAIN RATES IN SOUTHWEST MANITOBA
IS MAKING A RUN FOR THE INTERNATIONAL BORDER. PRECIPITABLE WATER
VALUES ARE NEAR 1.5", WITH HIGHER VALUES TO THE SOUTH ACROSS
EASTERN SD. CONVERGENT SOUTHERLY INFLOW AT 850 HPA OF 20-30 KTS
IS NOTED ON AREA VAD WIND PROFILES, WHICH IS IMPORTING MLCAPES OF
1000-3000 J/KG INTO THE REGION -- EVEN HIGHER UNDER THE CAPPING
INVERSION ACROSS SD. CIN REMAINS ACROSS THE AREA PER SPC
MESOANALYSES, THOUGH IT IS IN DECLINE.
THE EXPECTATION IS FOR THE COMPLEX IN CANADA TO FORWARD PROPAGATE
INTO THE REGION, SHORTENING THE WARM AIR ADVECTION THUNDERSTORM
BAND WITH TIME FROM NORTHWEST TO SOUTHEAST AND CREATING CELL
MERGERS. OF THE MESOSCALE GUIDANCE, THE 18Z CANADIAN REGIONAL,
12Z ARW, 12Z SPCWRF, AND 18Z NAM CONEST APPEAR TO HAVE THE BEST
HANDLE ON THE EXPECTED CONVECTIVE REGIME IN THIS AREA -- THE TRIO
OF HRRR RUNS HAVE STRUGGLED MIGHTILY. RECENT RAP RUNS INDICATE
CIN SHOULD NOT COMPLETELY ERODE IN THIS REGION, REACHING A MINIMUM
AROUND 01Z BEFORE REBUILDING. WITH TIME, SOUTHEAST PROPAGATION,
WITH SPEEDS UP TO 35 KTS, ARE POSSIBLE, THOUGH THIS DEGREE OF
MOVEMENT IS NOT EXPECTED UNTIL TOWARDS THE END OF THE PERIOD WHEN
VEERING IS SEEN IN THE LOW-LEVEL INFLOW. UNTIL THEN, HOURLY RAIN
RATES UP TO 2", WITH LOCAL AMOUNTS OF 2-4", ARE POSSIBLE IN THIS
REGION, WHICH COULD CAUSE FLASH FLOOD ISSUES.
ROTH
ATTN...WFO...BIS...FGF...
ATTN...RFC...NCRFC...
LAT...LON 49399844 49289730 48959614 48369542 47419587
46789672 47279757 48039896 48839984 49269942
Last Updated: 648 PM EDT SAT JUL 09 2016