311  
FXUS63 KMPX 211057  
AFDMPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN  
557 AM CDT MON AUG 21 2017  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 334 AM CDT MON AUG 21 2017  
 
THE SHORT TERM CONCERNS ARE CONVECTIVE/SEVERE POTENTIAL EARLY AND  
AGAIN LATER THIS AFTERNOON ALONG FRONTAL BOUNDARY.  
 
INITIALLY, SPC MESOSCALE ANALYSIS IS SHOWING MUCAPE TO 2000 J/KG,  
MID LEVEL LAPSE RATES TO 7.5 C/KM AND DEEP LAYER SHEAR TO 40KTS IN  
THE VICINITY OF THE NEARLY STATIONARY FRONTAL BOUNDARY OVER NORTHERN  
IOWA/SOUTHEAST MN. SCATTERED SHOWERS/STORMS DEVELOPED SHORTLY AFTER  
3 AM INTO SOUTH CENTRAL MINNESOTA, CLOSE TO OVERALL TRACK OF THE  
HRRR. SOME OF THESE STORMS COULD CONTAIN HAIL AND GUSTY WINDS DURING  
THE MORNING. THIS SHORT TERM CAM LIFTS THE AREA OF SHOWERS/STORMS  
NORTHEAST AFFECTING THE SOUTHEAST CORNER OF THE STATE AND MOVING  
INTO WEST CENTRAL WISCONSIN. WE WILL MENTION SCATTERED  
SHOWERS/STORMS AS THIS MOVES THROUGH THE AREA THROUGH ABOUT 16Z.  
 
MEANWHILE THE DAKOTAS TROUGH HAS DEVELOPED SOME SCATTERED CONVECTION  
AS WELL. AS IT APPROACHES THE WEST WE WILL HAVE TO INCLUDE SOME  
CHANCE POPS FOR THAT LATER MORNING/AFTERNOON. AS IT MOVES INTO  
MINNESOTA THE SURFACE BOUNDARY MAY WORK A BIT FARTHER NORTH DURING  
THE DAY AND WILL CONTINUE THE THREAT OF THUNDERSTORMS ALONG ACROSS  
THE EAST AND SOUTH INTO THIS EVENING. THE SEVERE THREAT REMAINS OVER  
THE FAR SOUTH INTO WEST CENTRAL WISCONSIN INTO THE EVENING THE  
TROUGH MOVES THROUGH, PUSHING THE FRONT TO THE SOUTHEAST. NOT  
ANTICIPATING GREAT VIEWING FOR THE ECLIPSE BECAUSE OF THE CONVECTIVE  
THREAT AND OVERALL CLOUDS EXPECTED.  
   
LONG TERM
 
(TUESDAY THROUGH SUNDAY)  
ISSUED AT 334 AM CDT MON AUG 21 2017  
 
TROUGHING ALOFT OVER THE EASTERN HALF OF THE CONUS WITH HIGH  
PRESSURE AT THE SURFACE REGIONALLY WILL YIELD CONTINUED COOL  
TEMPERATURES DURING THE LONG TERM FORECAST PERIOD. WITH RESPECT TO  
PRECIPITATION, CHANCES WILL BE LOW/LIMITED INTO NEXT FRIDAY GIVEN  
THE DOMINANCE OF SURFACE HIGH PRESSURE, BUT THEN THE ARRIVAL OF A  
SURFACE TROUGH NEXT WEEKEND BRINGS INCREASED SHOWER AND  
THUNDERSTORM CHANCES.  
 
THE PERIOD STARTS OUT COOL AND DRY, WITH HIGHS IN THE UPPER 60S TO  
MID 70S ON TUESDAY AND WEDNESDAY. WEDNESDAY AFTERNOON INTO  
THURSDAY WEAK RIPPLES ON THE WESTERN PERIPHERY OF THE  
AFOREMENTIONED EASTERN TROUGH COULD SPAWN A FEW SHOWERS, BUT  
PRECIP AMOUNTS AND COVERAGE WOULD BE VERY LIGHT.  
 
BY FRIDAY EVENING THERE IS RELATIVELY DECENT AGREEMENT AMONGST THE  
MODELS THAT A SURFACE TROUGH WILL BE BISECTING THE CENTRAL  
DAKOTAS, WITH A SHORTWAVE TROUGH APPROACHING FROM THE NORTHWEST ON  
THE HEELS OF THE EASTERN TROUGH. AS SPOKES OF ENERGY ASSOCIATED  
WITH THE TROUGH TO THE NORTHWEST PIVOT ACROSS THE AREA OVER THE  
WEEKEND ALONG WITH THE SURFACE TROUGH, MORE WIDESPREAD SHOWER AND  
THUNDERSTORM ACTIVITY IS EXPECTED. FOR NOW HAVE KEPT PRECIP  
CHANCES AROUND 40 PERCENT FOR THE WEEKEND, BUT WILL MOST LIKELY BE  
ABLE TO BUMP THOSE UP ONCE TIMING DETAILS ARE MORE CERTAIN WITH  
SUBSEQUENT MODEL RUNS.  
 

 
   
AVIATION
 
(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)  
ISSUED AT 600 AM CDT MON AUG 21 2017  
 
LOOKS LIKE SCATTERED CONVECTION WILL CLIP THE EASTERN TAF SIGHTS  
THIS MORNING. SOME MVFR CIGS POSSIBLE TO THE SOUTHER CLOSER TO THE  
SURFACE FRONT AFFECTING MAINLY KMKT THIS MORNING. THEN NEXT SURGE  
OF CONVECTION RIDES FROM WEST TO EAST OVER THE AREA LATER THIS  
AFTERNOON/EVENING. DID MENTION SOME TEMPO THUNDER OVER THE EASTERN  
AREAS. THEN CLEARING OVERNIGHT. SOME SMALL THREAT OF FOG MAINLY TO  
THE EAST...BUT EXPECT DRIER AIR TO WORK SOUTH WITH THE HIGH  
PRESSURE BUILDING IN.  
 
KMSP...COUPLE OF PERIODS OF THUNDER PSBL. FM 13Z-15Z OR SO AND  
THEN AGAIN AFTER 20Z AND ENDING THROUGH 02Z OR SO. THEN VFR REST  
OF PERIOD.  
 
/OUTLOOK FOR KMSP/  
TUE NIGHT...VFR. WIND NW 10 KTS.  
WED...VFR. WIND N 5 KTS.  
THU...VFR. WIND SE 5 KTS.  
 

 
   
MPX WATCHES/WARNINGS/ADVISORIES
 
 
WI...NONE.  
MN...NONE.  

 
 

 
 
SHORT TERM...DWE  
LONG TERM...LS  
AVIATION...DWE  
 
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