512
FXUS63 KMPX 171744
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1144 AM CST SUN NOV 17 2024
KEY MESSAGES
- WIDESPREAD SOAKING RAINFALL MONDAY NIGHT INTO TUESDAY. AN
INCH OR SO OF RAIN LOOKS LIKELY AT MOST LOCATIONS.
- COLDER AIR ARRIVES MID-WEEK WITH SOME SNOW ACCUMULATION
POSSIBLE ACROSS WESTERN MN TUESDAY NIGHT INTO WEDNESDAY.
- TEMPERATURES FOR THE END OF THE WEEK WILL BE MUCH COOLER WITH
HIGHS IN THE 30S AND LOWS IN THE 20S.
DISCUSSION
ISSUED AT 300 AM CST SUN NOV 17 2024
STEADY WESTERLY WINDS EARLY THIS MORNING WILL CONTINUE TODAY BEFORE
SLOWING BY THIS EVENING AS A COLD FRONT PUSHES WELL OFF TO THE EAST.
SOME POST-FRONTAL STRATUS CURRENTLY OVER WESTERN MN COULD CAUSE
CLOUDIER SKIES THAN EXPECTED FOR CENTRAL MN TODAY. BUT ELSEWHERE
MOSTLY SUNNY SKIES ARE EXPECTED WITH HIGHS IN THE UPPER 40S TO MID
50S. LOWS TONIGHT WILL BE CHILLY IN THE UPPER 20S TO MID 30S. MONDAY
MORNING AND EARLY AFTERNOON WILL BE DRY FOR THE ENTIRE AREA WITH
HIGHS WARMING INTO THE LOW TO MID 50S. CLOUDS WILL QUICKLY INCREASE,
THOUGH, AS OUR NEXT (AND MUCH DISCUSSED) LOW PRESSURE SYSTEM ARRIVES
FROM THE SOUTH. MOST GUIDANCE AGREES THAT THE NORTHERN EDGE OF THE
SYSTEM'S PRECIPITATION SHIELD WILL REACH THE I-90 CORRIDOR MID TO
LATE AFTERNOON MONDAY. RAIN WILL QUICKLY PROCEED NORTH, COVERING THE
ENTIRE AREA MONDAY EVENING, AND CONTINUING THROUGH MONDAY NIGHT. AS
THE SURFACE LOW CONTINUES TO LIFT NORTH DURING TUESDAY, RAIN SHOULD
END ACROSS SOUTHERN MN AS DRY AIR WRAPS IN FROM THE WEST. PWATS WITH
THIS SYSTEM CONTINUE TO BE NEAR CLIMATOLOGICAL MAXIMUM AT 1-1.25",
DUE TO THE MOISTURE'S STRONG CONNECTION WITH THE GULF OF MEXICO.
THUS, A WIDESPREAD SOAKING RAIN IS EXPECTED WITH THE HEAVIEST
RAINFALL OCCURRING MONDAY NIGHT. LATEST GUIDANCE HAS HINTED AT
SLIGHTLY LOWER QPF AMOUNTS (0.75-1.25") DUE TO THE LOW'S QUICK
TRANSLATION SPEED.
BY TUESDAY NIGHT, GUIDANCE AGREES THAT THE OCCLUDING SURFACE LOW
WILL STALL OUT SOMEWHERE OVER NORTHERN MN/SOUTH-CENTRAL CANADA AS IT
GETS DETACHED FROM ITS UPPER-LEVEL WAVE. MOST OF THE RAIN ASSOCIATED
WITH THE WARM SECTOR SHOULD BE OFF TO OUR NORTH. HOWEVER, WRAP-
AROUND PRECIP ON THE WEST SIDE OF THE LOW WILL BEGIN ADVECTING SOUTH
FROM THE NORTHERLY FLOW. AT THE SAME TIME, COLDER AIR FROM WESTERN
CANADA WILL ARRIVE OVER THE NORTHERN PLAINS AS A SECOND TROUGH FROM
THE PACIFIC NORTHWEST APPROACHES. THIS WILL CAUSE A CHANGE OVER FROM
RAIN, TO RAIN/SNOW MIX, TO ALL SNOW AS ONE GOES FARTHER WEST INTO
THE COLD AIR. GUIDANCE HAS CONTINUED TO FAVOR MOST OF THE SNOW BEING
OVER ND AND MANITOBA. HOWEVER, A GOOD PERCENTAGE OF THE GRAND
ENSEMBLE DOES FAVOR AT LEAST A COUPLE OF INCHES IN NORTHWESTERN TO
WESTERN MN. THIS WOULD BE ESPECIALLY TRUE IF THE LATEST ECMWF, EPS,
GEM, AND GEPS TRENDS OF A STRONGER LOW AND MORE WIDESPREAD AREA OF
PRECIP COME TO FRUITION. THE GFS HAS CONTINUED TO HOLD OUT WITH A
WEAKER AND MORE EASTERN SURFACE LOW, BUT EVEN THE GEFS HAS STARTED
TO COME AROUND TO THE FORMER SOLUTION. WARM GROUND TEMPS COULD
HINDER SNOWFALL ACCUMULATION AT FIRST BUT IF SUSTAINED SNOWFALL
RATES ARE HEAVY ENOUGH, THEN IT WOULDN'T BE UNREASONABLE TO SEE AT
LEAST A COUPLE OF INCHES IN OUR WESTERN MN COUNTIES TUESDAY NIGHT
INTO WEDNESDAY. THE LOW WILL SLOWLY MOVE EAST INTO THE UPPER GREAT
LAKES BEFORE NEW CYCLOGENESIS OCCURS FARTHER SOUTHEAST IN THE OHIO
VALLEY. WHAT THIS MEANS IS REST OF THE MPX CWA COULD SEE SNOW
SHOWERS (WITH LITTLE TO NO ACCUMULATION) THROUGH THURSDAY BEFORE
PRECIPITATION FINALLY DISSIPATES AS UPPER-LEVEL SUPPORT EXITS.
THE END OF THIS WEEK CONTINUES TO LOOK MUCH COOLER AS NORTHWESTERLY
FLOW SETS UP ACROSS THE NORTHERN PLAINS PROCEEDING THE
AFOREMENTIONED SYSTEM. EXPECT HIGHS IN ONLY THE 30S TO END THE
WEEK WITH OVERNIGHT LOWS POTENTIALLY REACHING THE TEENS IN
WESTERN MN. FORTUNATELY (OR UNFORTUNATELY, DEPENDING ON YOUR
VIEWS OF WINTER), LIFT AND MOISTURE CONTENT WITH THIS COLD AIR
WILL BE LACKING, MEANING LIKELY NO ADDITIONAL CHANCES FOR SNOW
FRIDAY THROUGH NEXT SUNDAY. WE'LL HAVE TO SEE IF WE STAY IN THE
COLD AIR FOR A PROLONGED PERIOD, OR IF WE GET SOME BREAKS OF
WARMTH. LONG-RANGE ENSEMBLES DO SUGGEST A MORE ZONAL FLOW
PATTERN STARTING THE BEGINNING OF NEXT WEEK. BUT, THOSE SAME
ENSEMBLES ALSO SUGGEST A GENERAL COOL DOWN OF OUR TEMPERATURES
TO MORE NORMAL LEVELS FOR LATE NOVEMBER.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1126 AM CST SUN NOV 17 2024
MORNING STRATUS HAS LIFTED NORTH OF THE TERMINALS, BEGINNING
WHAT WILL BE AN EXTENDED PERIOD OF CLEAR SKIES AND VFR
CONDITIONS FOR MOST OF THE 18Z TAF PERIOD. WEST/SOUTHWESTERLY
WINDS WILL GRADUALLY SUBSIDE THIS EVENING, BEFORE TURNING
SOUTHERLY BY DAYBREAK. FORECAST GUIDANCE TEASES THE IDEA OF
PATCHY FOG DEVELOPING AROUND 12Z AT A FEW OF THE TERMINALS,
HOWEVER THIS IS A LOW CONFIDENCE SCENARIO AT THIS TIME, SO DID
NOT INCLUDE IN THE TAFS. A BROAD SHIELD OF MODERATE TO HEAVY
RAIN, STRONG EASTERLY WINDS, AND MVFR/IFR OR LOWER CEILINGS AND
VISIBILITY WILL IMPACT ALL TERMINALS MONDAY EVENING INTO
TUESDAY. FORTHCOMING TAFS WILL BEGIN TO ADDRESS THE EXPECTED
CONDITIONS.
KMSP...CONDITIONS WILL BEGIN TO DETERIORATE MONDAY AFTERNOON,
WITH RAIN, LOW CEILINGS/VISIBILITY, AND GUSTY WINDS OUT OF THE
SOUTHEAST. WE HAVE INCLUDED A PROB30 AT THE END OF THE 18Z TAF
TO ADDRESS THIS POTENTIAL.
/OUTLOOK FOR KMSP/
TUE...MVFR/IFR. RA EARLY. WIND SE 10-15KTS BCMG W 20-25G35 KTS.
WED...MVFR. CHANCE -SHSN/IFR. WIND WNW 15-20G25-30KTS.
THU...MVFR CEILINGS POSSIBLE. WIND NW 15-20G25-30KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...CTG
AVIATION...STRUS
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