029
FXUS63 KMPX 221824
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1224 PM CST FRI NOV 22 2024
KEY MESSAGES
- COOLER WEATHER PERSISTS INTO NEXT WEEK, WITH TEMPERATURES FALLING
EVEN FURTHER BY THANKSGIVING DAY.
- A SMALL CHANCE FOR A FEW SHOWERS NORTH OF I-94 SUNDAY INTO
MONDAY.
DISCUSSION
ISSUED AT 304 AM CST FRI NOV 22 2024
THE MAIN STORY THIS MORNING ARE THE STARK DIFFERENCES BETWEEN THOSE
AREAS STUCK UNDER STUBBORN STRATUS CLOUDS VERSUS THOSE WITH CLEAR
SKIES, WITH WESTERN MINNESOTA SEEING LOWS DROPPING INTO THE UPPER
TEENS COMPARED TO LOW TO MID 30S IN EASTERN MN TO WESTERN WI WHERE
THE CLOUDS PERSIST. WE HAVE YET TO SEE SIGNIFICANT FOG DEVELOPMENT
THIS MORNING, HOWEVER BY THIS TIME TOMORROW MORNING THIS MAY BE A
DIFFERENT STORY WITH WEAKER WINDS AS THE SYSTEM MOVES AWAY AND
RADIATIONAL COOLING HELPING TO DROP TEMPERATURES TO DEW POINTS WITH
A BIT OF MOISTURE LEFT OVER FROM THE NOW MELTED SNOW AND THE LOW
LEVEL CLOUD COVER HAVING PUSHED TO THE EAST. WE WILL CONTINUE TO SEE
COLDER TEMPERATURES THROUGH THE WEEKEND AND INTO NEXT WEEK WITH THE
COLDEST WEATHER OF THE YEAR SO FAR EXPECTED BY THANKSGIVING DAY AND
INTO THE FOLLOWING WEEKEND, WITH A LACK OF ACTIVE WEATHER ACROSS THE
REGION. OUR UPPER LEVEL FLOW REMAINS ZONAL TO NORTHWESTERLY AS THE
DEEP SURFACE LOW MOVES TOWARDS THE EAST COAST BY TONIGHT WITH A LACK
OF A DOMINANT WEATHER SYSTEM OVER THE REGION TO INFLUENCE THE
WEATHER AS SURFACE CONDITIONS REMAIN STAGNANT. LATE SUNDAY INTO
MONDAY WOULD BRING OUR NEXT BEST CHANCE FOR PRECIPITATION PRIMARILY
NORTH OF I-94 AS THE SOUTHERN STREAM JET REMAINS TOO FAR SOUTH TO
PRODUCE SYNOPTIC SCALE LIFT OVER THE AREA, MEANING WE RELY ON A WEAK
SURFACE COLD FRONT FROM A CANADIAN SYSTEM TO BRING WEAK SHOWERS
PRIMARILY NORTH OF I-94, WITH MOST OF THE AREA REMAINING DRY.
AFTER THE SLIM CHANCE OF PRECIPITATION DEPARTS THE AREA BY MONDAY
EVENING, WE CONTINUE TO TREND COOLER AS RIDGING SETS UP OVER ALASKA,
CAUSING A SURGE OF COLDER AIR ALOFT TO SLIDE SOUTHEAST TOWARDS THE
NORTHERN PLAINS. THE SOUTHERN STREAM JET REMAINS TOO FAR SOUTH TO
PUSH THE COLD AIR OUT FASTER, AND WITH WEAK SURFACE HIGH PRESSURE
AND GENERAL SUBSIDENCE WE CAN EXPECT TO SEE SOME OF THAT COLDER AIR
BEGIN TO MIX DOWN TO THE SURFACE LATER IN THE WEEK. A FEW OF THE
ENSEMBLE MEMBERS WOULD TRY TO FORCE A BIT OF WEAK PRECIPITATION BY
LATE WEDNESDAY NIGHT, HOWEVER THIS APPEARS TO BE A LACKLUSTER CHANCE
AT BEST DRIVEN MAINLY BY AN OVERACTIVE POTENTIAL VORTICITY ANOMALY
PRESENT ON THE NORTHERN FRINGE OF THE SOUTHERN STREAM JET. GUIDANCE
IS GENERALLY SPORADIC IN BRINGING IN FURTHER SMALL PRECIPITATION
CHANCES, WITH THE ONLY REAL CONSENSUS BEING PERSISTENT NORTHWESTERLY
FLOW ALOFT BRINGING ARCTIC AIR CLOSER AND CLOSER TO THE REGION LATER
IN THE WEEK. BY FRIDAY, WE COULD BE LOOKING AT HIGHS STRUGGLING TO
GET OUT OF THE MID 20S, MARKING A COLD END TO THE MONTH AS IT LIKELY
PERSISTS INTO EARLY DECEMBER.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1138 AM CST FRI NOV 22 2024
STRATUS WILL BE OUR PROBLEM THIS PERIOD. UNDER THE SURFACE RIDGE
AXIS IN WESTERN MN, THIS STRATUS HAS GONE AWAY, BUT THE WESTERN
EDGE OF THE STRATUS DECK HAS STAYED PARKED ALL MORNING AND WITH
THAT SURFACE RIDGE AXIS MOVING LITTLE THROUGH TONIGHT, THE
STRATUS DECK WILL BE STUBBORN TO MOVE EAST AS WELL. FOR WHERE
STRATUS IS CURRENTLY IN PLACE, RAP FORECAST SOUNDINGS SHOW A
THIN MOISTURE LAYER REMAINING IN PLACE THROUGH THE DAY ON
SATURDAY. LOOKING AT WINDS, THEY WILL REMAIN LIGHT UNTIL
SATURDAY NIGHT THIS LIMITED MIXING WILL MAKE IT THAT MUCH HARDER
TO PUSH THE STRATUS OUT. ANOTHER BIT OF UNCERTAINTY IS THAT THE
WEST EDGE OF THE STRATUS WILL LIKELY DEVOLVE INTO DENSE FOG
OVERNIGHT. THIS WOULD PUT STC AND MKT IN THE FOG ZONE. FOR STC,
FORECAST SOUNDINGS SHOW A THICK LAYER OF MID/UPPER CLOUDS MOVING
IN TONIGHT, BUT THAT'S NOT THE CASE FOR MKT, SO TRENDED THE MKT
TAF IN THE FOG DIRECTION FOR TONIGHT. IN THE END, YOU CAN SUM
UP THESE TAFS AS PESSIMISTIC (OUTSIDE OF AXN/RWF) AND SIMPLE.
KMSP...THIS TIME OF YEAR, THE SAFEST THING TO DO WHEN IN STRATUS
IS TO KEEP THAT STRATUS GOING. GIVEN THE MOIST LAYER REMAINING
IN THE RAP SOUNDINGS AND THE SLOW MOVEMENT OF THE CLEARING, WE
LEFT THE STRATUS IN PLACE THROUGH TONIGHT. IN FACT, WE MAY NOT
START SEEING ENOUGH LOW LEVEL FLOW TO START PUSHING THE STRATUS
OUT OF HERE UNTIL SATURDAY NIGHT... KEPT THE HEIGHTS CONSISTENT,
THOUGH THERE IS CONCERNS WE COULD SEE THE CLOUD DECK LOWER TO
IFR LEVELS OVERNIGHT INTO SATURDAY MORNING.
/OUTLOOK FOR KMSP/
SUN...VFR. WIND SE 5-10KTS.
MON...VFR/MVFR, CHC -RASN. WIND NW 10-15G20KTS.
TUE...VFR. WIND NW 5-10 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...TDH
AVIATION...MPG
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