518  
FXUS63 KMPX 081654  
AFDMPX  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN  
1054 AM CST THU DEC 8 2022  
   
UPDATE
 
ISSUED AT 1050 AM CST THU DEC 8 2022  
UPDATED FOR THE 18Z AVIATION DISCUSSION  
 

 
   
SHORT TERM
 
(TODAY THROUGH FRIDAY)  
ISSUED AT 534 AM CST THU DEC 8 2022  
 
KEY MESSAGES  
 
- WINTER WEATHER ADVISORY FOR SOUTHERN MINNESOTA. SNOW POSSIBLY  
MIXED WITH RAIN/FREEZING RAIN THIS EVENING THROUGH EARLY FRIDAY.  
 
WE WILL START OUT PARTLY CLOUDY TODAY BEFORE LOW CLOUDS MOVE IN AS A  
DEVELOPING SURFACE LOW ACROSS THE PLAINS SENDS MOIST, SOUTHERLY FLOW  
NORTHWARD. PW VALUES NEARING A HALF INCH OR BETTER WILL OVERSPREAD  
THE SOUTHERN HALF OF MINNESOTA BY THIS EVENING AS THE SURFACE LOW  
TRACKS ACROSS SOUTHERN IOWA. DESPITE BEING ON THE NORTHERN SIDE OF  
THIS SYSTEM, P-TYPE HAS BEEN A FORECAST CHALLENGE. MODELS HAVE  
BACKED OFF A BIT ON THE DURATION OF A WARM NOSE AS THE COLUMN COOLS  
SHORTLY AFTER PRECIP ONSET, SO HAVE REDUCED FREEZING RAIN  
ACCUMULATIONS TO AROUND TWO HUNDREDTHS OR LESS ALONG THE I-90  
CORRIDOR. AS EXPECTED, THIS HAS LED TO A BUMP IN SNOWFALL TOTALS,  
WITH 3-5 INCHES LOOKING LIKELY ALONG THE I-90 CORRIDOR WITH 1-3  
INCHES NORTH OF US-14. WHILE THERE IS A CHANCE THAT SOME BANDING  
COULD OCCUR AND LEAD TO TOTALS CLOSER TO THE 6 INCH MARK, DECIDED  
THAT THERE IS STILL ENOUGH UNCERTAINTY WITH HOW MUCH PRECIP FALLS AS  
FREEZING RAIN TO JUSTIFY STAYING WITH THE WINTER WEATHER ADVISORY.  
ADDITIONALLY, THE OVERALL TIMING OF THE SYSTEM SEEMS A BIT SLOWER,  
SO HAVE ADJUSTED THE ADVISORY TO BEGIN AT 00Z THIS EVENING. SNOW  
WILL MOVE OUT BY LATE FRIDAY MORNING WITH TEMPERATURES WARMING TO  
NEAR TO JUST ABOVE FREEZING.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 534 AM CST THU DEC 8 2022  
 
KEY MESSAGES  
 
- A PERIOD OF FREEZING DRIZZLE IS POSSIBLE SATURDAY MORNING.  
 
- A LARGE STORM SYSTEM WILL IMPACT THE NORTHERN PLAINS INTO THE  
UPPER MS VALLEY MONDAY NIGHT THROUGH THURSDAY. IT WILL DRAW  
SIGNIFICANT AMOUNTS OF MOISTURE NORTH. THE MPX AREA LOOKS TO BE IN A  
MESSY TRANSITION ZONE OF RAIN AND WINTRY P-TYPES.  
 
THE FIRST PROBLEM TO TACKLE WILL BE A TROUGH COMING OUT OF THE  
ROCKIES FRIDAY NIGHT AND MOVING INTO THE GREAT LAKE THROUGH THE DAY  
ON SATURDAY. THE COMBINATION OF STRONG ISENTROPIC LIFT AND PVA OUT  
AHEAD OF THE WAVE WILL PROVIDE BACKGROUND SYNOPTIC LIFT FOR  
PRECIPITATION. THE PROBLEM? THE DGZ WILL BE UP BETWEEN 12K AND 15K  
FEET AGL, BUT THE SATURATED LAYER LOOKS TO BE ONLY 6K TO 9K FEET  
DEEP. THIS LEAVES US WITH SOUNDINGS THAT DON'T SHOW MUCH SUPPORT FOR  
ICE NUCLEATION, WHICH MEANS SUPER-COOLED WATER DROPS. THIS MEANS  
PRIMARY P-TYPE SATURDAY MORNING INTO THE AFTERNOON WITH THIS WAVE  
WOULD BE EITHER FZDZ OR DZ DEPENDING ON THE SURFACE TEMPERATURE. BY  
THE AFTERNOON, DEEPER MOISTURE STARTS TO ARRIVE, WHICH MAY ALLOW FOR  
BETTER SNOW CHANCES IN WESTERN WI. STILL, GIVEN THE FORECAST  
SOUNDINGS, CONSIDERABLY UPPED THE MENTION OF FZDZ WITH THIS UPDATE  
FROM WHAT WE HAD GOING. MOST GUIDANCE KEEPS QPF UNDER 0.05" ON  
SATURDAY. THE LIGHT QPF, COMBINED WITH TEMPERATURES NEAR 30 AND  
RISING AS THE PRECIP MOVES IN AND THROUGH WILL HOPEFULLY LIMIT THE  
POTENTIAL IMPACTS TO TRAVEL FROM THIS SETUP, BUT THIS IS SOMETHING  
WE'LL HAVE TO WATCH CLOSELY.  
 
BEHIND THIS TROUGH, WE'LL QUICKLY SEE H5 HEIGHTS RISE ACROSS THE  
CENTRAL CONUS IN RESPONSE TO H5 LOW DIGGING INTO THE GREAT BASIN.  
THIS WILL RESULT IN BENIGN WEATHER SUNDAY AND MONDAY, WITH HIGHS  
GETTING INTO THE 30S, WITH THE ONLY NOTICEABLE SENSIBLE WEATHER  
BEING AN UPTICK IN SOUTHEAST WINDS ON MONDAY AS A STRONG AREA OF  
LOW PRESSURE BEGINS TO TAKE SHAPE OVER NORTHEAST CO.  
 
MONDAY NIGHT THROUGH THURSDAY LOOKS, MESSY... FOR THIS FAR OUT, THE  
MODELS ARE ACTUALLY IN FAIRLY GOOD AGREEMENT ON THINGS LIKE WHERE  
THE SURFACE AND H7 LOWS WILL TRACK. THE MAIN SHIFT WE SAW WITH THE  
00Z MODELS IS A SLIGHT SOUTHERN SHIFT IN THE LOW TRACK. THIS STILL  
LEAVES US A SCENARIO WHERE THE P-TYPE TRANSITION ZONE IS OVER OUR  
CWA, BUT THERE ARE INCREASING CHANCES FOR A SIGNIFICANT SNOWFALL  
EVENT NORTHWEST OF A MADISON TO MORA LINE.  
 
THE CURRENT FORECAST FOR THE LOW TRACK TAKES IT OUT OF NORTHEAST CO  
AND TO THE CENTRAL KS/NEB BORDER 12Z TUE, IT WILL BECOME OCCLUDED  
ON TUESDAY AND BE OVER EASTERN SODAK 12Z WED, AND BY 12Z THU IT WILL  
BE OVER CENTRAL WI, WITH THE LOW PASSING DIRECTLY OVER THE MPX AREA  
ON WEDNESDAY. STRONG AND DEEP SOUTHERLY FLOW OUT AHEAD OF THIS  
SYSTEM WILL TRANSPORT SIGNIFICANT AMOUNTS OF MOISTURE NORTH, WITH  
PWATS POTENTIALLY PUSHING AN INCH IN THE MPX AREA, WHICH IS NEAR THE  
CLIMATOLOGICAL MAX FOR THE MONTH OF DECEMBER. PRECIP LOOKS TO PUSH IN  
RAPIDLY MONDAY NIGHT WITHIN A STRONG ZONE OF WAA. THE PROBLEM IS  
THIS WAA LOOKS TO BRING IN A STRONG WARM NOSE ALOFT. THE RESULT OF  
WHICH IS SEEN IN THE MODELS WITH A POTPOURRI OF WINTRY PRECIP TYPES  
BEING POSSIBLE AS THIS PRECIP LIFTS INTO THE MPX AREA. TUESDAY  
MORNING, SURFACE TEMPERATURES WILL RISE ABOVE FREEZING FOR MUCH OF  
THE AREA, WHICH MEANS A TRANSITION TO RAIN FOR ALL BUT POSSIBLY THE  
NORTHWEST CORNER OF OUR AREA. TUESDAY AFTERNOON, STRONG LIFT WITHIN  
THE PRECIP BAND MOVING IN CAUSES THE WARM NOSE TO COLLAPSE, WITH P-  
TYPES TUESDAY AFTERNOON THROUGH THE REST OF THE STORM LOOKING TO BE  
RAIN OR SNOW DEPENDING ON LOW LEVEL TEMPERATURE PROFILES. TUESDAY  
AFTERNOON, WE'LL SEE A TROWAL AND ASSOCIATED DRY SLOT MOVE IN BEHIND  
THIS INITIAL BAND OF PRECIP, WITH IT LOOKING LIKE IT MAY BE  
DIFFICULT TO GET MUCH MORE THAN DRIZZLE TUESDAY NIGHT THROUGH MUCH  
OF WEDNESDAY. BY WEDNESDAY AFTERNOON, THE H7 LOW WILL BE MOVING  
ALONG THE MN/IA BORDER AND AS IT DOES SO, WE'LL BEGIN TO SEE THE DRY  
SLOT SHIFT EAST, WITH CHANCES FOR SNOW RETURNING AS THE LOW PUSHES  
INTO THE GREAT LAKES ON THURSDAY. GIVEN THE AMOUNT OF MOISTURE  
COMING IN, WE'RE SEEING SOME SIGNIFICANT QPF AMOUNTS FOR DECEMBER  
STANDARDS, WITH THE EPS AND GEFS MEAN QPFS NEXT WEEK EXCEEDING 1"  
FOR PRETTY MUCH OUR ENTIRE CWA. FOR REFERENCE, THE AVERAGE LIQUID  
EQUIVALENT PRECIP IN DECEMBER FOR MSP IS 1.17", THERE A NUMEROUS  
ENSEMBLE MEMBERS SHOWING QPF WITH THIS SYSTEM EXCEEDING WHAT WE  
NORMALLY SEE FOR LIQUID FOR THE ENTIRE MONTH OF DECEMBER. THERE ARE  
STILL MANY MOVING PARTS THIS FAR OUT, BUT ONE THING IS FOR SURE, WE  
WILL BE DEALING WITH A SIGNIFICANT WINTER STORM NEXT WEEK, IT'S JUST  
A MATTER OF PINNING DOWN WHERE THINGS LIKE THE RAIN/SNOW LINE AND  
DRY SLOT SETUP.  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 1050 AM CST THU DEC 8 2022  
 
VFR TO START THE PERIOD BEFORE LOW CLOUDS MOVE IN THIS AFTERNOON  
AHEAD OF A SYSTEM THAT WILL BRING PRECIP TO OUR SOUTHERN SITES AFTER  
03Z. TIMING OF PRECIPITATION HAVE BEEN PUSHED BACK TO MATCH MODEL  
TRENDS. MODELS HINT AT SOME IFR CEILINGS MOVING IN AHEAD OF THE  
SYSTEM BY THIS AFTERNOON, MAINLY FOR KEAU AND KMKT, WITH OBS  
BEGINNING TO MATCH THAT. SNOW, POTENTIALLY MIXED WITH RAIN AT TIMES,  
WILL SPREAD NORTH AND EASTWARD FROM SOUTH DAKOTA/IOWA THROUGH THE  
OVERNIGHT WITH THE BULK OF THE PRECIP EXPECTED AFTER 05Z. SNOWFALL  
RATES COULD NEAR 1"/HOUR AT TIMES, PARTICULARLY FOR KMKT, THROUGH THE  
END OF THE PERIOD. WINDS REMAIN LIGHT AND TURN SOUTHEASTERLY TODAY  
AHEAD OF THE SYSTEM AND GO EASTERLY ON THE BACKSIDE.  
 
KMSP...TIMING HAS BEEN PUSHED BACK A BIT FROM THE PREVIOUS FORECAST  
WITH THE HEAVIEST SNOW EXPECTED BETWEEN 09Z AND 13Z. HOWEVER, NOT  
ANTICIPATING THE 1"/HOUR RATES TO MAKE IT AS FAR NORTH AS KMSP. SNOW  
WILL TAPER OFF TOWARDS THE END OF THE PERIOD. THE TREND WITH  
LATER/LIGHTER SNOWFALL CONTINUES AS THE SYSTEM TRENDS FURTHER SOUTH  
WITH THE MAIN PRECIPITATION.  
 
/OUTLOOK FOR KMSP/  
SAT...VFR, CHC MVFR/-FZDZ. WIND SE 5-10KTS.  
SUN...VFR. WIND SE 5-10KTS.  
MON...VFR, CHC MVFR LATE. WIND SE 5-10KTS.  
 

 
   
MPX WATCHES/WARNINGS/ADVISORIES
 
 
MN...WINTER WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST FRIDAY  
FOR BLUE EARTH-BROWN-FARIBAULT-FREEBORN-GOODHUE-LE SUEUR-  
MARTIN-NICOLLET-REDWOOD-RICE-STEELE-WASECA-WATONWAN.  
 
WI...NONE.  

 
 

 
 
SHORT TERM...DYE  
LONG TERM...MPG  
AVIATION...BPH  
 
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