111  
FXUS63 KMPX 131945  
AFDMPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN  
245 PM CDT MON JUL 13 2020  
   
SHORT TERM
 
(THIS EVENING THROUGH TUESDAY NIGHT)  
ISSUED AT 244 PM CDT MON JUL 13 2020  
 
THE MAIN STORY FOR THE SHORT TERM IS THE SEVERE WEATHER RISK  
ACROSS MUCH OF THE AREA. A SURFACE LOW AND AN ASSOCIATED COLD  
FRONT IS SITUATED IN CENTRAL NORTH DAKOTA AND WILL CONTINUE TO  
MOVE OFF TO THE NORTHEAST THROUGH TOMORROW. CLEAR SKIES THROUGH  
MUCH OF THE MORNING AND INCREASING SOUTHERLY WINDS HAVE ALLOWED  
TEMPERATURES TO WARM INTO THE 80S WITH DEW POINTS IN THE MID TO  
UPPER 60S. WINDS ARE ESPECIALLY STRONG ACROSS WESTERN MINNESOTA  
WITH GUSTS OF 25-30+ KTS. A CU FIELD STARTED POPPING UP AROUND 18Z  
ACROSS SOUTHERN MINNESOTA AND WESTERN WISCONSIN WHILE CLOUD COVER  
AHEAD OF AN ONGOING AREA OF CONVECTION ASSOCIATED WITH THE  
AFOREMENTIONED SURFACE LOW MAKES ITS WAY INTO WESTERN MINNESOTA.  
EXPECT CLOUD COVER TO CONTINUE TO INCREASE THROUGH THE REMAINDER  
OF THE AFTERNOON.  
 
WHILE THE 12Z SOUNDING FROM MPX SHOWS A STRONG CAPPING INVERSION,  
EXPECT THAT TO ERODE BY LATE THIS AFTERNOON AND EVENING. OUR 12Z  
SOUNDING ALSO DID NOT HAVE PARTICULARLY IMPRESSIVE LAPSE RATES,  
BUT FURTHER TO THE WEST, THE 12Z ABR SOUNDING SHOWED MUCH BETTER  
INSTABILITY WITH A 700MB-500MB LAPSE RATE OF 7.9C/KM. MODELS SHOW  
THIS BETTER INSTABILITY MOVING WESTWARD INTO OUR AREA BY THIS  
EVENING. WHILE THERE WILL BE PLENTY OF CAPE ACROSS CENTRAL AND  
SOUTHERN MINNESOTA, THE BETTER SHEAR LOOKS TO BE IN NORTHERN  
MINNESOTA AND BACK INTO NORTH DAKOTA. CAMS SUGGEST THAT A FEW  
DISCRETE CELLS MAY FORM LATE THIS EVENING, WITH ALL SEVERE HAZARDS  
POSSIBLE, BEFORE THINGS TRANSITION TO MORE OF A LINEAR MODE WITH  
DAMAGING WINDS BECOMING THE MAIN THREAT. THIS LINE OF STORMS WILL  
MOVE SOUTHEAST ACROSS THE STATE AND WILL WEAKEN SOME AS IT  
APPROACHES THE TWIN CITIES METRO BY AROUND MIDNIGHT. EXPECTING  
THIS LINE TO DISSIPATE FURTHER AS IS GETS OUT OF THE MORE  
FAVORABLE ENVIRONMENT ACROSS SOUTHEASTERN MINNESOTA/WESTERN  
WISCONSIN.  
 
HOWEVER, WE'RE NOT DONE YET... THE COLD FRONT WILL MOVE THROUGH  
THE REGION ON THE HEELS OF THIS ACTIVITY TUESDAY BRINGING  
ANOTHER ROUND OF HEAVY RAIN. THERE WILL BE PLENTY OF MOISTURE WITH  
PWATS NEARING 2". THIS, COMBINED WITH ANY PREVIOUS RAINFALL FROM  
MONDAY'S ROUND OF ACTIVE WEATHER, WILL LEAD TO TWO DAY RAINFALL  
TOTALS OF WELL OVER AN INCH IN MANY PLACES. RAIN AND CLOUD COVER  
THROUGH THE MAJORITY OF THE DAY WILL PREVENT TEMPERATURES FROM  
REACHING EVEN 80 DEGREES IN MOST LOCALES, WHICH WILL BE SOME OF  
THE COOLEST DAYTIME HIGHS WE'VE SEEN IN ABOUT THREE WEEKS. BY  
TUESDAY EVENING, THE FRONT MOVES ON AND TAKES THE RAIN AND CLOUD  
COVER WITH IT, BRINGING CLEARING SKIES FROM WEST TO EAST  
OVERNIGHT.  
   
LONG TERM
 
(WEDNESDAY THROUGH MONDAY)  
ISSUED AT 244 PM CDT MON JUL 13 2020  
 
HIGH PRESSURE WILL MOVE INTO THE UPPER MIDWEST FOLLOWING THE COLD  
FRONTAL PASSAGE TUESDAY NIGHT. TEMPERATURES AND DEWPOINTS WILL  
ALSO DECREASE AND WEDNESDAY'S WEATHER WILL BE VERY COMFORTABLE  
WITH MOSTLY SUNNY SKIES, LIGHT WINDS, AND HIGHS IN THE LOW 80S.  
THURSDAY WILL BE SLIGHTLY WARMER, AS THE CANADIAN CONTINENTAL  
AIRMASS ONLY STAYS FOR A QUICK VISIT BEFORE IT IS KICKED OUT BY  
SOUTHWESTERLY FLOW FROM THE HIGH PLAINS. A SLIGHT CHANCE OF  
SHOWERS AND THUNDERSTORMS ACROSS CENTRAL MN EXISTS, AS THE TAIL-  
END IMPULSE OF THE TROUGH MOVING INTO THE NORTHERN PLAINS TODAY  
PASSES THROUGH. HOWEVER, MEAGER LIFT SHOULD LIMIT PRECIPITATION  
COVERAGE. THE STRONGER LOW-LEVEL SOUTHWESTERLY WAA BEGINS TOWARDS  
THURSDAY NIGHT AS RIDGING SHIFTS INTO SOUTH-CENTRAL CANADA IN  
ADVANCE OF A SHORTWAVE TROUGH IN THE PACIFIC NORTHWEST. FORECAST  
MODELS DO TRY TO DEVELOP SOME OVERNIGHT CONVECTION ACROSS EASTERN  
SD AND SOUTHERN MN FROM THE WAA THURSDAY NIGHT. HOWEVER, WITH 850  
MB TEMPERATURES NEARING 20 DEGREES C CAPPING MAY VERY WELL LIMIT  
CONVECTIVE DEVELOPMENT.  
 
THE GFS CONTINUES TO BE THE OUTLIER WITH REGARD TO TEMPERATURES ON  
FRIDAY. IT PRODUCES A RATHER LARGE AREA OF QPF OVER MN FRIDAY  
MORNING AND AFTERNOON, WHICH LIMITS THE NORTHWARD ADVANCEMENT OF  
THE SURFACE WARM FRONT. ON THE OTHER HAND, THE ECMWF LIMITS THE  
REGIONAL EXTENT OF CONVECTION TO IA AND SOUTHERN MN AS WELL AS THE  
DURATION. BECAUSE OF THIS, FORECAST HIGHS FOR FRIDAY FOR THE  
ECMWF ARE IN THE UPPER 80S (ABOUT 7 DEGREES WARMER THAN THE GFS).  
QUITE UNCOMFORTABLE WEATHER BEGINS FRIDAY NIGHT AS FORECAST LOWS  
ARE PROJECTED TO BE IN THE LOW 70S FOR SOUTHERN MN TO NEAR 70  
ELSEWHERE. DEWPOINTS WILL INCREASE INTO THE LOW 70S ON SATURDAY  
AND HIGH TEMPERATURES INTO THE LOW-90S. AS ONE MAY EXPECT WITH THE  
LARGE AMOUNTS OF HEAT AND MOISTURE, THERE SHOULD BE NO SHORTAGE  
OF INSTABILITY FOR CONVECTION. MODELS PRODUCE QPF OVER MOST OF THE  
NORTHERN PLAINS THROUGHOUT SATURDAY AS THE AFOREMENTIONED PACIFIC  
NORTHWEST TROUGH IMPINGES ON OUR REGION. THUNDERSTORMS ARE LIKELY  
WITH ANY OF THE PRECIPITATION THAT DEVELOPS AND SEVERE WEATHER IS  
ALSO A POSSIBILITY. HOWEVER, SATURDAY IS CURRENTLY TOO FAR AWAY  
FOR FORECAST CONFIDENCE TO BE HIGH.  
 
NEXT WEEK LOOKS TO BE SLIGHTLY COOLER WITH MORE ACTIVE WEATHER AS  
A SERIES OF SHORTWAVE TROUGHS WILL SLIDE THROUGH THE NORTHERN  
PLAINS. SO FOR THOSE NEEDING WATER FOR YOUR LAWN OR GARDENS, MORE  
HELP SHOULD BE ON THE WAY.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)  
ISSUED AT 115 PM CDT MON JUL 13 2020  
 
MULTIPLE PERIODS OF CONVECTION WILL BE THE MAIN CONCERN FOR THIS  
TAF PERIOD. VFR CONDITIONS WILL REMAIN THROUGH THE REST OF THIS  
AFTERNOON THEN CONDITIONS ARE EXPECTED TO DETERIORATE THROUGH THE  
EVENING HOURS AS CLUSTERS OF THUNDERSTORMS DEVELOP OVER EASTERN ND  
INTO NORTHWESTERN MN THEN CONGEAL AS THEY SHIFT SE THROUGH  
CENTRAL-SOUTHERN MN INTO WESTERN WI. CONVECTION LOOKS TO FIRST HIT  
OUR WESTERN MN TAFS BETWEEN ROUGHLY 00Z-04Z THEN CONTINUE PUSHING  
EASTWARD. IFR CONDITIONS ARE LIKELY, MAINLY DUE TO VISIBILITY IN  
MOD-HVY RAIN, WITH MVFR CEILINGS. SOME OF THE STORMS MAY ALSO BE  
STRONG-SEVERE DURING THE EVENING HOURS. THE BULK OF THIS FIRST  
ROUND WILL END PRIOR TO DAYBREAK BUT THEN A MORE HEAVY/PERSISTENT  
RAIN THREAT DEVELOPS AFTER DAYBREAK AND CONTINUES FOR THE FIRST  
HALF OF THE DAY TUESDAY. MVFR CONDITIONS ARE MOST LIKELY BUT IFR  
CONDITIONS CANNOT BE RULED OUT. AS THIS ACTIVITY WILL BE OCCURRING  
WITH A FRONTAL PASSAGE, WINDS WILL ALSO SHIFT DIRECTIONS.  
GUSTY/BREEZY SE WINDS THROUGH THIS AFTERNOON WILL DIMINISH GOING  
INTO THE EVENING THEN CAN BE EXPECTED TO SWING TO NW OVERNIGHT  
INTO TOMORROW MORNING.  
 
KMSP...MOST SHORT-TERM MODELS GENERALLY AGREE THAT THE BEST  
CHANCES FOR CONVECTION AROUND KMSP WILL BE 03Z-07Z AND AGAIN  
14Z-18Z, BUT THOSE TIMES COULD VARY BY ABOUT AN HOUR OR SO ON  
EITHER SIDE. THERE WILL ALSO BE INTERMITTENT SHOWERS BEFORE/AFTER  
THE EVENING CONVECTION BUT THE RAINFALL TOMORROW LOOKS TO BE MORE  
SUSTAINED. THERE ARE ALSO THE STRONG-SEVERE HAZARDS WITH THE  
STORMS ALONG WITH POTENTIAL FOR FREQUENT LIGHTNING.  
 
/OUTLOOK FOR KMSP/  
WED...VFR. WIND SW 5 KTS.  
THU...VFR. WIND SW 5-10 KTS.  
FRI...MAINLY VFR. CHC SHRA/TSRA/MVFR. WIND S 5-10 KTS.  
 

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

 
 

 
 
SHORT TERM...DYE  
LONG TERM...CTG  
AVIATION...JPC  
 
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