Graphic for MPD #0523

MESOSCALE PRECIPITATION DISCUSSION 0523...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
705 AM EDT FRI JUL 21 2017

CORRECTED FOR THE FIRST LINE OF THE FIRST PARAGRAPH

AREAS AFFECTED...NORTHERN PLAINS/UPPER MIDWEST

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

VALID 211046Z - 211526Z

SUMMARY...THUNDERSTORMS ARE EXPANDING IN COVERAGE WITHIN A WARM
ADVECTION REGIME.  HOURLY RAIN RATES TO 2.5" WITH LOCAL AMOUNTS TO
4" ARE POSSIBLE.

DISCUSSION...ELEVATED CONVECTION HAS BEEN DEVELOPING OVER THE PAST
2-3 HOURS ACROSS SOUTHEAST SD, SOUTHERN MN, AND NORTHEAST IA IN A
DIVERGENT AREA ALOFT AHEAD OF A SHORTWAVE MOVING THROUGH THE
WESTERN DAKOTAS.  PRECIPITABLE WATER VALUES OF ~2" WERE REPORTED
WITHIN RECENT GPS DATA.  EFFECTIVE BULK SHEAR OF ~35 KTS LIES
ACROSS THE AREA.  INFLOW AT 850 HPA IS 20-35 KTS PER VAD WIND
PROFILE INFORMATION, IMPORTING MU CAPE VALUES OF 500-2000 J/KG
INTO THE REGION.

MOST OF THE GUIDANCE, OUTSIDE OF OCCASIONAL HRRR AND EXPERIMENTAL
HRRR RUNS, HAS EITHER BEEN TOO DELAYED WITH THE FORMATION OF THIS
CONVECTION OR HAS MISSED THE BOAT ENTIRELY.  THUNDERSTORMS WITH
SOME ORGANIZATION ARE EXPECTED TO MOVE GENERALLY EASTWARD AT 20-25
KTS PER FORWARD PROPAGATING VECTORS WITH THE BAND EDGING NORTHEAST
WITH TIME.  CONSIDERING THE AVAILABLE MOISTURE AND RECENT
TRAINING, HOURLY RAIN RATES TO 2.5" WITH LOCAL AMOUNTS TO 4" ARE
EXPECTED THROUGH 15Z.  THEREAFTER, LOW-LEVEL INFLOW BEGINS TO BACK
WHICH ALONG WITH CIN REDUCTION COULD LEAD TO SOME CONVECTIVE
REORGANIZATION AND BREAK UP THE TRAINING BAND.

ROTH

ATTN...WFO...ABR...ARX...DMX...DVN...FSD...MKX...MPX...

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

LAT...LON   45129555 44849351 43719126 42278984 41168996
            41429087 41559103 41559105 42279221 43199394
            43729671 43679866 43979877 44789817


Last Updated: 705 AM EDT FRI JUL 21 2017