MESOSCALE PRECIPITATION DISCUSSION 0314
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
518 PM EDT SUN JUN 17 2018

AREAS AFFECTED...SOUTHEAST SD...SOUTHERN MN...NORTHERN WI...

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

VALID 172120Z - 180230Z

SUMMARY...MOIST ENVIRONMENT AND TRAINING CELLS POSE FLASH FLOODING
RISK THROUGH EARLY EVENING.

DISCUSSION...21Z SURFACE ANALYSIS DEPICTS AN ELONGATED SURFACE
WAVE OVER NW WI BACK TOWARD THE TWIN CITIES WITH THE SFC BOUNDARY
EXTENDING BACK TO SW MN AND SE SD INTO THE SAND HILLS OF NORTH
CENTRAL NEB.  VERY MOIST AND UNSTABLE ENVIRONMENT REMAINS POOLED
ALONG THE BOUNDARY WITH SFC TDS IN THE LOW TO MID 70S AND SBCAPES
RANGING FROM 2000 J/KG IN SD TO 3500 J/KG NEAR THE TWIN CITIES
INTO N WI.  WEAK TO MODERATE DIVERGENCE ALOFT AT THE WEAKLY
ANTICYCLONIC CURVED PEAK OF 3H FLOW BUT BECOMING INCREASINGLY
CONFLUENT TO A STRENGTHENING JET ENTRANCE REGION OVER LAKE
SUPERIOR WILL PROVIDE SOME PERIPHERAL UVVS HELP FOR E MN INTO N
WI.  BETTER SFC MOISTURE CONVERGENCE EXISTS WITH BETTER ORTHOGONAL
FLOW TO THE BOUNDARY ACROSS SD INTO SW MN...WHICH REDUCES TO
NEARLY PARALLEL ACROSS CENTRAL TO N WI ATTM.  CURRENT GOES-16
1-MINUTE IMAGERY SHOW CONVECTIVE DEVELOPMENT IN THE TWO REGION S
WITH A LOCAL MINIMUM THROUGH CENTRAL MN WITH ONLY A FEW SMALLER
TCU AT THIS TIME.

STEERING FLOW ABOVE THE SFC IS FAIRLY UNIDIRECTIONAL AND RANGING
FROM 20-30 KTS PER VWP NETWORK IN THE CLOUD BEARING FLOW...WHICH
WILL SUPPORT A TRAINING PROFILE.  PROPAGATION VECTORS DO SUPPORT
SLOW SOUTHEASTWARD TRACK SO TRAINING IS NOT PERFECTLY IDEAL BUT
LIKELY TO BE SUFFICIENT FOR COMPOUNDING TOTALS CAPABLE OF FLASH
FLOODING.  GIVEN DEEP MOISTURE WITH TPWS AOA 2.0" WILL SUPPORT
VERY EFFICIENT RAINFALL PRODUCTION AND LIKELY RATES OF 2"/HR OR
GREATER AND GIVEN THE TRAINING POCKETS OF 2-4" TOTALS ARE EXPECTED
THROUGH THE AREA OF CONCERN AND GIVEN ANTECEDENT CONDITIONS
ESPECIALLY IN E MN AND N WI...FLASH FLOODING IS CONSIDERED
POSSIBLE.

GALLINA

ATTN...WFO...ARX...DLH...FSD...GRB...MPX...

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

LAT...LON   45739160 45689090 45518939 45058922 44539024
            43969279 43679422 43429543 42859794 43419819
            44409628 45099448 45709238