MESOSCALE PRECIPITATION DISCUSSION 0428
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1156 PM EDT MON JUL 09 2018

AREAS AFFECTED...FAR NERN MT INTO ND

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

VALID 100355Z - 100955Z

SUMMARY...FLASH FLOODING WILL BE POSSIBLE OVER THE NEXT FEW HOURS
FROM THE NORTHERN MT/ND BORDER INTO CENTRAL ND WITH RAIN RATES OF
1-2 IN/HR AND LOCALIZED TOTALS OF 2-3 INCHES THROUGH .

DISCUSSION...REGIONAL RADAR AND INFRARED SATELLITE IMAGERY THROUGH
0330Z SHOWED THE CONJOINING OF A FEW STRONG SUPERCELLS INTO A
GROWING CLUSTER OF CONVECTION WITH MULTIPLE UPDRAFTS INFERRED
THROUGH SATELLITE AND LIGHTNING DATA. THE ACTIVITY IS OCCURRING
JUST NORTH OF A WARM/STATIONARY FRONT WHICH EXTENDED EAST FROM A
LOW IN NORTHEASTERN MT INTO WESTERN ND AND SOUTHEASTWARD THROUGH
SD AS OF 03Z. AN MCS APPEARS LIKELY TO DEVELOP ROOTED NEAR ~800 MB
VIA FORECAST RAP SOUNDINGS...AND PROPAGATION VECTORS SUPPORT A
SOUTHEASTWARD MOVEMENT TO CONVECTION ALONG AN INSTABILITY POOL
ALIGNED NEAR AND NORTH OF THE FRONTAL BOUNDARY.

THERE IS A SHORT TERM FLASH FLOOD THREAT IN THE VICINITY OF THE
ORGANIZING MCS WITH TRAINING/REPEATING OF RAIN CORES BEFORE
SUFFICIENT ORGANIZATION TAKES PLACE. AS THE WARM FRONT LIFTS NORTH
OVERNIGHT...MUCAPE IS EXPECTED TO INCREASE OVER CENTRAL ND...AT
LEAST FOR A BRIEF PERIOD AFTER ROUGHLY 06Z. SUFFICIENT INSTABILITY
AND INCREASINGLY DIFFLUENT FLOW ALOFT WHEN COMBINED WITH A 35-40
KT LOW LEVEL JET FROM THE SOUTH...MAY ALLOW FOR ADDITIONAL
CONVECTION ALONG/AHEAD OF THE LIFTING WARM FRONT IN ADVANCE OF THE
FORECAST MCS TRACK WITH CELL MERGERS POSSIBLE...LOCALLY INCREASING
RAINFALL TOTALS.

OVERALL...THE FLASH FLOOD THREAT SHOULD BE LIMITED...BUT A FEW
PLACES COULD SEE RAINFALL RATES OF 1-2 IN/HR AND LOCALIZED TOTALS
OF 2-3 INCHES BY 10Z.

OTTO

ATTN...WFO...BIS...FGF...GGW...

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

LAT...LON   49040516 49020463 49029885 48999883 47839846
            46899870 46479987 46190165 46370287 47420399
            48280564 48450581 48730557