MESOSCALE PRECIPITATION DISCUSSION 0641
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1010 PM EDT SUN SEP 04 2016
 
AREAS AFFECTED...EASTERN ND...NORTHWEST MN...NORTHEAST SD 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 050209Z - 050709Z
 
SUMMARY...ISOLATED FLASH FLOOD THREAT GIVEN LOW FLASH FLOOD
GUIDANCE AND MDT TO HVY RAINFALL WITH ISOLATED CONVECTIVE EMBEDDED
CONVECTIVE ELEMENTS. 

DISCUSSION...GOES-E WV LOOP AND RADAR MOSAIC DENOTE A SIGNIFICANT
SHORTWAVE LIFTING INTO CENTRAL SD ATTM AS WELL AS AN EXITING WAVE
OVER SW ONTARIO.  THIS HAS LEFT AN IDEAL DYNAMIC SETUP ACROSS THE
DISCUSSION AREA FOR BROAD SCALE ASCENT.  3H JET ANALYSIS SHOWS
WEAK SHORTWAVE RIDGING BETWEEN THE WAVES WHILE DUAL WITH DUAL JET
STRUCTURE (RIGHT ENTRANCE/LEFT EXIT).  AT THE SURFACE WELL DEFINED
SURFACE BOUNDARY FROM NW MN TOWARD KABR...WHILE 850 FLOW SUPPORTS
SOME ANAFRONTAL ASCENT TO REACH A STRONG WIND SHIFT/CONVERGENCE
LINE NW OF THE FRONTAL ZONE AND MORE ALIGNED WITH THE UVV FROM THE
JET ASCENT.  RAP ANALYSIS ALSO INDICATES MODERATE MID-LEVEL
INSTABILITY WITH MUCAPE IN THE 1000 J/KG RANGE...ALLOWING FOR
STRONGER VERTICAL ASCENT AND EMBEDDED CONVECTIVE ELEMENTS WITH IR
TOPS TO THE MID -60C ALONG THIS 850 BOUNDARY.  THIS SUPPORTS RAIN
RATES UP INTO THE 1.5"/HR RANGE POSSIBLE (GIVEN TPWS VALUES IN
THAT RANGE).  AS THE S/W LIFTS NORTH...THERE SHOULD BE LIMITED
EASTWARD PROGRESSION OF THE CONVERGENCE BOUNDARY ALLOWING FOR
PROLONGED RAINFALL TO REACH TOTALS CAPABLE FOR ISOLATED SPOT
ECLIPSING THE LOWERED FFG IN THE VICINITY...PARTICULARLY ACROSS NE
ND.  

FURTHER SW...STRONG CONVERGENCE IN ADVANCE OF THE MCS SHOULD
SUPPORT STRONGER CORES WITH INCREASED RAIN RATES THOUGH DURATION
AND THEREFORE TOTALS MAY BE LIMITED TO VERY SHORT-TERM FLASH
FLOODING CONCERNS THERE AS WELL.  A VERY LIMITED AREAL THREAT FOR
LONGER DURATION HVY RAINFALL WOULD BE FOR TRAINING CELLS ALONG THE
NW PERIPHERY OF THE MCV/SHORTWAVE CENTER WHERE FLOW/CONVERGENCE IS
WRAPPED BACK AGAINST THE FORWARD PROGRESS OF THE WAVE ITSELF. 

GALLINA

ATTN...WFO...ABR...BIS...FGF...

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

LAT...LON   49449483 48489467 47099506 45949616 44839814 
            45040019 46160001 47069920 48669700 49089589