687  
FXUS63 KMPX 250932  
AFDMPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN  
432 AM CDT WED MAY 25 2016  
   
SHORT TERM
 
(TODAY AND TONIGHT)  
ISSUED AT 432 AM CDT WED MAY 25 2016  
 
AN ACTIVE MORNING/AFTERNOON IS IN STORE FOR THE AREA AS  
NEGATIVELY TILTED TROUGH CURRENTLY EXTENDING FROM CENTRAL SODAK  
DOWN TOWARD KC SWINGS THROUGH THE UPPER MS VALLEY REGION. CAMS AND  
DETERMINISTIC MODELS ARE ALL SIMILAR IN SHOWING A NW TO SE  
ORIENTED LINE OF THUNDERSTORMS COMING UP WITH A SURGE IN MOISTURE  
TRANSPORT AND THETA- E. THERE WAS ALSO GOOD AGREEMENT IN THE  
MODELS WITH THIS FEATURE COMING THROUGH A BIT SLOWER THAN WHAT THE  
PREVIOUS FORECAST HAD, SO DID SLOW THE ONSET OF PRECIP DOWN QUITE  
A BIT...WITH STORMS LOOKING TO MOVE INTO SW PORTIONS OF THE MPX  
CWA AROUND 12Z, REACH ST. CLOUD AND THE TWIN CITIES AROUND LUNCH  
TIME AND NOT PUSH INTO WESTERN WI UNTIL THE AFTERNOON. BEHIND THIS  
WAVE, MODELS ARE SHOWING STRONG MID LEVEL SUBSIDENCE AND DRYING,  
WHICH SHOULD REALLY LIMIT THE AMOUNT OF ACTIVITY WE SEE IN THE  
WAKE OF THIS SYSTEM. AS A RESULT, DID DECREASE POPS CONSIDERABLY  
IN THE WAKE OF THE MAIN PRECIP BAND. LEFT BEHIND BROAD BUSHED LOW  
CHANCE POPS FOR THE AFTERNOON, AS A MOIST ENVIRONMENT WILL REMAIN  
IN PLACE, WHICH WOULD BECOME QUITE UNSTABLE IF SOME SUNSHINE CAN  
BE RECEIVED, BUT IS BEGINNING TO LOOK LIKE JUST ABOUT ALL OF OUR  
PRECIP TODAY WILL BE WITH THE WAVE MOVING IN THIS MORNING.  
 
FOR QPF FROM THIS CONVECTION, IT DOES NOT LOOK OVERLY EXCESSIVE.  
CELL MOVEMENT LOOKS TO BE REASONABLE AND THERE IS NOT MUCH  
INDICATION OF THERE BEING TRAINING, WITH RAINFALL AMOUNTS AROUND A  
HALF INCH LOOKING COMMON, THOUGH A FEW HEAVIER CORRIDORS AROUND AN  
INCH WILL BE POSSIBLE.  
 
TONIGHT, ANOTHER SHORTWAVE WILL BE COMING OUT OF THE DAKOTAS.  
MODELS OVERNIGHT SHOW THIS WAVE HEADING FOR NORTHERN MN, FARTHER  
NORTH THAN WHAT GUIDANCE WAS SHOWING YESTERDAY, SO REDUCED POPS  
OVERNIGHT AS WELL. THE MOST BULLISH MODEL FOR TONIGHT IS THE NCAR  
ENSEMBLE WRF. ALL 10 OF ITS MEMBERS SHOW A BOWING MCS WORKING  
ACROSS SOUTHERN MN OUT AHEAD OF THE DAKOTAS WAVE. YOU CAN NOT FIND  
ANY OTHER SUPPORT FOR THIS SOLUTION IN THE CAMS OR DETERMINISTIC  
MODELS, BUT GIVEN MOIST/UNSTABLE ENVIRONMENT WE WILL HAVE IN  
PLACE, IT'S NOT COMPLETELY OUT OF THE REALM OF POSSIBILITY.  
 
FOR THE SEVERE THREAT, OUR MAIN CHANCE LOOKS TO BE WITH THE WAVE  
COMING AT US THIS MORNING. INSTABILITY WITH THIS LINE LOOKS TO BE  
ON THE ORDER OF 1000-2000 J/KG OF MUCAPE AND THERE IS GOOD TURNING  
OF THE WINDS, SO A FEW STRONGER CELLS CAPABLE OF PRODUCING  
MARGINALLY SEVERE HAIL AND FOR THE AFTERNOON, WIND GUSTS WILL BE  
POSSIBLE. SEVERE THREAT BEHIND THIS WAVE IS VERY MUCH CONDITIONAL,  
BUT IF STORMS DEVELOP THIS AFTERNOON, THEY WOULD FIND THEMSELVES  
IN A FAVORABLE SUPERCELL ENVIRONMENT. FOR TONIGHT, THE NCAR WRF  
SOLUTION HAS A GOOD WIND EVENT FOR US. UNFORTUNATELY, THE ONLY  
PERIOD WE HAVE MUCH CONFIDENCE IN CONVECTION OCCURRING IS WITH THE  
WAVE COMING UP NOW AND MORE LIMITED INSTABILITY AND WEAKER MID  
LEVEL LAPSE WITH IT SEEM TO POINT TO ANOTHER DAY OF MAINLY NON-  
SEVERE STORMS WITH A FEW STRONGER TROUBLE MAKERS.  
   
LONG TERM
 
(THURSDAY THROUGH TUESDAY)  
ISSUED AT 432 AM CDT WED MAY 25 2016  
 
A WARM, HUMID, STORMY PATTERN WILL CONTINUE THROUGHOUT THE LONG  
TERM PERIOD - ALTHOUGH THERE WILL LIKELY BE PROLONGED DRY PERIODS  
MIXED IN AT ANY GIVEN LOCATION.  
 
THURSDAY: FORECAST CONFIDENCE - MEDIUM TO HIGH.  
 
BEHIND THE WAVE TODAY AND TONIGHT, MID LEVEL RIDGING WILL BUILD IN  
THURSDAY. SUBSIDENCE WITH THE RIDGING WILL SCOUR OUT THE CLOUDS  
EARLY WITH FORECAST SOUNDINGS SHOWING A RATHER DRY COLUMN FOR  
MUCH OF THE DAY. THE DRIER AIR, FULL SUN, AND SUBSIDENCE SHOULD  
SEND TEMPERATURES INTO THE MID OR UPPER 80S OVER MUCH OF THE AREA.  
MUCH OF THE GUIDANCE APPEARS A BIT LOW IN THIS SITUATION,  
PARTICULARLY WITH 925 MB TEMPS OF +22 TO +25C. BY LATE AFTERNOON,  
THE NEXT UPPER WAVE WILL ALREADY BE APPROACHING FROM THE  
SOUTHWEST. A STRENGTHENING 850 MB JET AND SURFACE WARM FRONT ALONG  
THE I-80 CORRIDOR WITH VERY UNSTABLE AIR ALONG AND TO THE SOUTH  
OF IT WILL SPARK THUNDERSTORMS ACROSS NEBRASKA AND IOWA AROUND MID  
AFTERNOON. AS THE WAVE LIFTS NORTHEAST ACROSS THE PLAINS TOWARD  
THE UPPER MISSISSIPPI VALLEY, THESE STORMS SHOULD BUILD NORTHWARD  
TOWARD THE MINNESOTA/IOWA BORDER BY LATE AFTERNOON. A FEW OF THESE  
MAY BE SEVERE, ESPECIALLY IF THE DEEPER MOISTURE CAN WORK NORTH  
TOWARD MINNESOTA BY EARLY EVENING. THIS IS SOMEWHAT IN DOUBT  
THOUGH GIVEN EARLY DAY CONVECTION ACROSS IOWA AND MISSOURI  
EARLIER, WHICH COULD KEEP THE FRONT FURTHER SOUTH FOR MUCH OF THE  
DAY THAN IS CURRENTLY FORECAST. WHILE LIKELY WEAKENING, THE  
ACTIVITY ACROSS IOWA AND NEBRASKA WILL LIFT NORTH ACROSS MINNESOTA  
AND WISCONSIN THURSDAY NIGHT.  
 
THURSDAY NIGHT THROUGH SATURDAY NIGHT: FORECAST CONFIDENCE -  
MEDIUM.  
 
ACTIVITY ACROSS IOWA AND NEBRASKA WILL LIFT NORTH ACROSS  
MINNESOTA AND WISCONSIN THURSDAY NIGHT AND FRIDAY MORNING. NOT  
EXPECTING TOO MUCH SEVERE POTENTIAL WITH THIS WITH A STABILIZING  
BOUNDARY LAYER AND WEAKENING LAPSE RATES. THE UPPER LOW OVER THE  
WESTERN HIGH PLAINS THURSDAY NIGHT WILL SLOWLY ADVANCE  
NORTHEASTWARD TOWARD THE NORTHERN PLAINS/UPPER MISSISSIPPI VALLEY  
SATURDAY NIGHT AND SUNDAY. ITS ENERGY WILL ELONGATE WITH TIME AND  
SEVERAL SMALLER SCALE DISTURBANCES MAY DRIFT ACROSS DURING THIS  
TIME. POTENTIAL FOR ACTIVITY THROUGHOUT THIS PERIOD WILL HEAVILY  
DEPEND ON PREVIOUS DAYS' CONVECTIVE EVOLUTION AND RESULTANT  
OUTFLOW BOUNDARIES/MESOSCALE CONVECTIVE VORTEXES. HOWEVER, GIVEN  
THE LIKELIHOOD OF SOME DESTABILIZATION EACH DAY AND FAVORABLE  
UPPER SUPPORT, SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE  
EXPECTED EACH PERIOD THROUGH THE FIRST HALF OF THE WEEKEND.  
 
SUNDAY THROUGH TUESDAY: FORECAST CONFIDENCE - MEDIUM.  
 
WITH THE UPPER LOW PUSHING OUT SATURDAY NIGHT, SUPPORT WILL BE  
LOST FOR WIDESPREAD THUNDERSTORM DEVELOPMENT SUNDAY AND MONDAY.  
RIDGING WILL FINALLY BUILD ACROSS THE SOUTHERN PLAINS AND SHOULD  
CAP DISTURBANCES FROM ORIGINATING THERE EARLY NEXT WEEK. INSTEAD,  
A TROUGH DIPPING INTO THE NORTHERN ROCKIES WILL SPREAD HEIGHT  
FALLS EASTWARD TO THE UPPER MIDWEST TUESDAY WHEN STORM CHANCES  
INCREASE AGAIN.  
 

 
   
AVIATION
 
(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)  
ISSUED AT 112 AM CDT WED MAY 25 2016  
 
SW FLOW ALOFT MEANS ENERGY HELPING GENERATE TSRA FROM SODAK DOWN  
THROUGH KS WILL BE HEADING THIS WAY THROUGH THE NIGHT. CONFIDENCE  
IS INCREASING IN A NW TO SE ORIENTED BAND OF SHRA/TSRA MOVING  
ACROSS MN DURING THE MORNING AND INTO WI DURING THE AFTERNOON.  
USED A COMBINATION OF THE HRRR/RAP/NAM TO TIME THIS ACTIVITY IN  
TO TAFS, WHICH RESULTED IN DELAYING PRECIP ONSET FROM WHAT THE 00Z  
TAFS HAD BY AN HOUR OR TWO. BEHIND THIS INITIAL WAVE, UNCERTAINTY  
IN THE FORECAST IS HIGH. THERE WILL BE A LOT OF MID LEVEL DRYING  
AND SUBSIDENCE IN THE WAKE OF THIS MORNINGS WAVE. CURRENT THINKING  
IS THIS DRYING AND SUBSIDENCE WILL LIMIT STORM REDEVELOPMENT IN  
THE AFTERNOON, WITH EXTENSIVE CLOUD COVER LIMITING DESTABILIZATION  
AND POTENTIAL FOR SEEING MORE SHRA/TSRA FROM THE AFTERNOON INTO  
WEDNESDAY NIGHT. MAIN CONCERN WITH WHAT THESE TAFS IS THEY MAY  
NOT BE CAPTURING THE POTENTIAL FOR A FEW HOURS OF MVFR CIGS IN  
THE WAKE OF THE RAIN WHEN LOOKING AT RH IN THE 925-850MB LAYER OFF  
THE RAP/NAM. WOULD LIKE TO SEE BETTER MVFR CEILING PROBS IN THE  
SREF AND MORE CLOUDS IN THAT LEVEL FORECAST ON THE HRRR THOUGH  
BEFORE GETTING TOO CARRIED AWAY WITH THAT.  
 
KMSP...ALTHOUGH STILL A GOOD DEAL OF VARIABILITY IN THE CAMS WITH  
HOW WIDESPREAD TSRA WILL BE WITH THE BAND MOVING UP THIS MORNING,  
THERE IS GOOD AGREEMENT ON THE 16Z TO 19Z PERIOD BEING MOST LIKELY  
FOR SEEING TSRA, SO HIT THIS PERIOD WITH A PREVAILING TSRA  
GROUP. AFTER THAT, REALLY DON'T SEE MUCH POTENTIAL FOR SHRA/TSRA  
THE REST OF THE PERIOD.  
 
/OUTLOOK FOR KMSP/  
THU...MAINLY VFR. CHC TSRA/MVFR. WIND S TO SW 5 KTS.  
FRI...MAINLY VFR. CHC TSRA/MVFR. WIND SE 5 KTS.  
SAT...MVFR. TSRA/MVFR LIKELY. WIND SSE 5 KTS.  
 

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

 
 

 
 
SHORT TERM...MPG  
LONG TERM...BORGHOFF  
AVIATION...MPG  
 
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