562
FXUS63 KMPX 181230
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
630 AM CST MON NOV 18 2024
KEY MESSAGES
- WIDESPREAD SOAKING RAINFALL THIS AFTERNOON INTO TUESDAY
MORNING. AN INCH OR SO OF RAIN APPEARS LIKELY AT MOST
LOCATIONS.
- COLDER AIR ARRIVES MID-WEEK. SOME SNOW ACCUMULATION POSSIBLE
ACROSS WESTERN MINNESOTA TUESDAY NIGHT THROUGH WEDNESDAY.
- TEMPERATURES WILL BE MUCH COLDER BY THE END OF THE WORK WEEK,
WITH HIGHS IN THE 30S AND LOWS IN AT LEAST THE 20S.
DISCUSSION
ISSUED AT 259 AM CST MON NOV 18 2024
CLEAR SKIES AND LIGHT WINDS TONIGHT HAVE ALLOWED TEMPERATURES TO
DROP INTO THE LOW TO MID 30S. EVEN SOME PESKY FOG HAS DEVELOPED
AT EAU AND HAS BEEN FLUCTUATING BACK AND FORTH AT THE ASOS.
HIGHS TODAY WILL WARM INTO THE LOW TO MID 50S BUT CLOUD COVER
WILL QUICKLY INCREASE FROM SOUTH TO NORTH AS OUR NEXT LOW
PRESSURE SYSTEM APPROACHES. ADDITIONALLY, AS THE SURFACE
PRESSURE GRADIENT TIGHTENS, EASTERLY WINDS WILL ALSO INCREASE,
ESPECIALLY THIS AFTERNOON AND INTO THIS EVENING WHEN GUSTS COULD
REACH 35 MPH. CAMS CONTINUE TO SHOW THE NORTHERN EDGE OF THE
LOW'S LARGE PRECIPITATION SHIELD REACHING THE MN/IA BORDER BY
1-2 PM THIS AFTERNOON. FROM THEN, RAIN WILL CONTINUE TO SPREAD
NORTH COVERING THE ENTIRE CWA BY 8 PM AND LIKELY LASTING FOR THE
ENTIRE NIGHT. ONLY WHEN THE SURFACE LOW FINALLY PASSES NORTH
OVER US AND THE DRY SLOT STARTS TO WRAP IN ON THE LOW'S SOUTH
SIDE WILL PRECIPITATION BEGIN TO SHUT OFF FROM SOUTH TO NORTH
DURING TUESDAY. RAINFALL AMOUNTS WILL GENERALLY BE 1-1.5" CWA-
WIDE, ACCORDING TO GUIDANCE. LOCALLY HIGHER AMOUNTS COULD OCCUR
ACROSS SOUTHERN MN WHERE A MEAGER AMOUNT OF CONVECTIVE
INSTABILITY IS FORECAST. MOST OF THE CWA SHOULD DRY OUT AS DRY
AIR ON THE BACKSIDE ADVECTS COUNTER-CLOCKWISE, EXCEPT FOR
PORTIONS OF CENTRAL MN (AXN, STC, BRD, ETC.). HERE, FORECAST
SOUNDINGS HANG ON TO GREATER LOW-LEVEL SATURATION, SO DRIZZLE
AND REDUCED VISIBILITIES COULD BECOME AN ISSUE TUESDAY MORNING
INTO THE AFTERNOON. WINDS WILL ALSO TURN TO WESTERLY DURING
TUESDAY AND REMAIN STRONG AFTER THE SURFACE LOW PASSES OVERHEAD.
THE LOW WILL OCCLUDE AND CONTINUE NORTHWARD BEFORE STALLING OUT
OVER EASTERN MANITOBA/WESTERN ONTARIO TUESDAY NIGHT.
WHILE THE RAIN ASSOCIATED WITH THE ARCHING COLD FRONT/WARM
SECTOR WILL BE LOCATED WELL TO OUR NORTH BY TUESDAY EVENING,
LIGHT WRAP- AROUND PRECIP ON THE WEST SIDE OF THE LOW WILL BE
MOVING SOUTHWARD INTO WESTERN MN. AT THE SAME TIME, MUCH COLDER
AIR ASSOCIATED WITH A STRONG UPPER-LEVEL TROUGH WILL BE ARRIVING
FROM THE WEST. THE PRECIP IN WESTERN MN WILL ORIGINALLY BE
RAIN, BUT AS THE COLUMN COOLS FROM CAA A CHANGE TO A RAIN-SNOW
MIX TO EVENTUAL SNOW IS EXPECTED. THE TRANSITION TO SNOW SHOULD
BE COMPLETE BY WEDNESDAY MORNING WITH LIGHT SNOW SPREADING OVER
THE REMAINDER OF OUR CWA FROM WEST TO EAST DURING WEDNESDAY
MORNING. WE WILL LIKELY SEE SNOW SHOWERS INTO WEDNESDAY NIGHT,
BUT LITTLE ACCUMULATION IS EXPECTED OWING TO THE FORECAST LOW
SNOWFALL RATES AND WARM GROUND TEMPERATURES. HOWEVER, A COUPLE
OF INCHES MAY BE POSSIBLE IN WESTERN MN WHERE BETTER LIFT AND
SLIGHTLY BETTER SNOWFALL RATES ARE FORECAST. SOME LIGHT FREEZING
DRIZZLE IS ALSO POSSIBLE, MAINLY IN CENTRAL MN, WHERE FORECAST
SOUNDINGS ARE HINTING AT SUB-FREEZING LOW-LEVEL SATURATION THAT
IS BELOW THE DGZ. TEMPERATURES WILL PLUMMET WITH WEDNESDAY'S
HIGHS ONLY EXPECTED IN THE 30S. COMBINED WITH THE STILL STRONG
WESTERLY WINDS AND SNOW SHOWERS, WEDNESDAY LOOKS LIKE AN
UNPLEASANT DAY TO BE OUTSIDE.
GUIDANCE SUGGESTS THE LIGHT SNOW WILL DISSIPATE AND MOVE EAST
EARLY THURSDAY MORNING. THE REMAINDER OF THE WEEK LOOKS COLD
AND DRIER WITH POTENTIALLY LOTS OF CLOUD COVER. COLD AIR IS
FORECAST TO KEEP FUNNELING INTO THE NORTHERN PLAINS THROUGH THE
END OF THE WEEK AS NORTHWESTERLY FLOW SETS UP DOWNSTREAM OF A
RIDGE OVER THE ROCKIES. OUR FIRST REAL TASTE OF WINTER STARTS
THURSDAY NIGHT AS LOWS WILL DROP TO NEAR 20 IN WESTERN MN WITH
20S TO NEAR 30 ELSEWHERE. TEMPERATURES ONLY GET WORSE FRIDAY AND
SATURDAY NIGHT WHEN MID TO UPPER TEENS ARE POSSIBLE IN WESTERN
MN. NOT MUCH WARMING WILL OCCUR DURING THE DAY EITHER AS HIGHS
IN THE MID 20S TO MID 30S ARE FORECAST. A SLIGHT REBOUND IN
TEMPERATURES IS POSSIBLE EARLY NEXT WEEK AS LONG-RANGE MODELS
SHOW THE NORTHWEST FLOW BRIEFLY SUBSIDING. HOWEVER, THESE SAME
MODELS ALSO DRAG THE POOL OF REALLY COLD AIR THAT WAS OVER
WESTERN CANADA OVER TO THE NORTHERN HIGH PLAINS AND CANADIAN
PRAIRIES. THE NORTHERLY JETSTREAM ALSO GETS DISPLACED MORE TO
THE SOUTH ACROSS THE CONUS DURING NEXT WEEK. THE COLDER AIR WILL
THEN BE MORE EASILY ACCESSIBLE TO ANY SHORTWAVES THAT FORM
WITHIN THE FLOW. THUS, WE WOULD HAVE BETTER CHANCES AT WINTRY
TEMPERATURES AND PRECIPITATION TOWARDS THE END OF NOVEMBER AND
BEGINNING OF DECEMBER.
AVIATION /12Z TAFS THROUGH 12Z TUESDAY/
ISSUED AT 630 AM CST MON NOV 18 2024
SIGNIFICANT CHANGES TO TAKE PLACE WITHIN THIS TAF DURATION. ALL
SITES START AS VFR WITH FAIRLY LIGHT SE WINDS. MVFR-WORTHY
CLOUDS WILL MOVE IN FROM THE SOUTH THIS AFTERNOON, ALONG WITH
WIDESPREAD RAIN NOT TOO FAR BEHIND, BOTH OF WHICH WILL
OVERSPREAD MN/WI FROM SOUTH-TO-NORTH LATE THIS AFTERNOON INTO
THIS EVENING. HAVE USED TEMPO GROUPS TO INDICATE SOME WIGGLE
ROOM WITH WHEN THE RAIN MAY COMMENCE. RAIN WITH LOW STRATUS
WILL PERSIST OVERNIGHT THROUGH SUNRISE TUESDAY, WITH CEILINGS
DROPPING INTO IFR RANGE. VISIBILITIES WILL GENERALLY RUN WITHIN
MVFR RANGE BUT POCKETS OF HEAVIER RAIN WILL PUSH VISIBILITY INTO
IFR RANGE. ALONG WITH THE CLOUD/RAIN COMPLICATIONS, WINDS WILL
BACK TO EASTERLY AND BECOME BREEZY/GUSTY BY LATE AFTERNOON AND
SUCH SPEEDS WILL CONTINUE TONIGHT THROUGH TOMORROW. SUSTAINED
SPEEDS WILL RUN 15-20KTS WITH GUSTS 25-35KTS. STRONG NOCTURNAL
JETTING WITH THE OCCLUDED SYSTEM LIFTING NORTH WILL SPREAD A JET
OF 50KTS AROUND 2KFT ALOFT ACROSS MAINLY CENTRAL-EASTERN MN INTO
WESTERN WI, PRODUCING BOTH A SPEED AND DIRECTIONAL VECTOR
DIFFERENCE, SO HAVE ADDED LLWS MENTION INTO THE AFFECTED TAFS.
KMSP...VFR CONDITIONS TO PREVAIL THRU MID-AFTERNOON THEN
CONDITIONS DETERIORATE QUICKLY AS LOW STRATUS AND RAIN ARRIVES
FROM THE SOUTH. POTENTIAL FOR RAIN TO DEVELOP AS EARLY AS 20Z
BUT VERY LIKELY BY 23Z, WITH STEADY RAIN (SOME HEAVY AT TIMES)
TO PERSIST OVERNIGHT INTO SUNRISE TUESDAY MORNING. CEILINGS WILL
DROP UNDER 1000FT PRIOR TO THE TUESDAY MORNING PUSH. RAINFALL
WILL DIMINISH LATE TUESDAY MORNING BUT THE DEGRADED CONDITIONS
WILL REMAIN, PARTICULARLY IFR CEILINGS. STRONG EASTERLY WINDS
WILL DEVELOP BY LATE AFTERNOON AND CONTINUE THROUGH THE
OVERNIGHT HOURS. IN ADDITION, STRONG LOW LEVEL JETTING WILL
PRODUCE WINDS AROUND 50KTS AT 2KFT THIS EVENING THROUGH THE
OVERNIGHT HOURS.
/OUTLOOK FOR KMSP/
WED...MVFR. CHANCE -SHSN/IFR. WIND W 15-25G25-35KTS.
THU...MVFR CIGS LIKELY. WIND NW 15-20G25-30KTS.
FRI...VFR. WIND NW 10-15KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...CTG
AVIATION...JPC
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