238
FXUS63 KMPX 162038
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
238 PM CST SAT NOV 16 2024
KEY MESSAGES
- MILD AND WINDY WEATHER CONTINUES THIS AFTERNOON, WITH SLIGHTLY
COOLER BUT STILL BREEZY CONDITIONS ON SUNDAY.
- WIDESPREAD SOAKING RAINFALL MONDAY NIGHT INTO TUESDAY. AN INCH OR
SO OF RAIN LOOKS LIKELY AT MOST LOCATIONS.
- COOLER AIR ARRIVES FOR THE SECOND HALF OF NEXT WEEK, WITH
HIGHS IN THE 30S AND LOWS IN THE 20S.
DISCUSSION
ISSUED AT 230 PM CST SAT NOV 16 2024
EARLY AFTERNOON SURFACE ANALYSIS CAPTURES ~998MB LOW PRESSURE
LOCATED IN SOUTH CENTRAL NORTH DAKOTA. THE ANALYZED TIGHT PRESSURE
GRADIENT EAST OF THE SURFACE LOW HAS PRODUCED STRONG SOUTHEASTERLY
WINDS ACROSS SOUTH CENTRAL MINNESOTA AND WESTERN WISCONSIN. THE
COMBINATION OF WARM AIR ADVECTION AND EFFICIENT MIXING HAS ALLOWED
FOR TEMPERATURES TO WARM INTO THE 50S ACROSS MUCH OF SOUTH CENTRAL
MINNESOTA. A COLD FRONT WILL MOVE THROUGH THE REGION OVER THE
COMING HOURS, TIED TO THE NORTHEASTWARD MOVEMENT OF THE SURFACE
LOW. NOT MUCH CHANGE THE EXPECTED DRY PASSAGE OF THE FRONT, WITH
THE ONLY MENTION OF 20-30% POPS ACROSS THE EASTERNMOST COUNTIES
IN WESTERN WISCONSIN. STEEP LAPSE RATES AND BETTER SATURATION
WITHIN THE COLUMN MAY PROMOTE SCATTERED SHOWERS LATER THIS
EVENING. THE GUSTY SOUTH/SOUTHEASTERLY WINDS ARE FORECAST TO
TURN WESTERLY BEHIND THE FRONTAL PASSAGE. SLIGHTLY COOLER, BUT
STILL ABOVE AVERAGE HIGHS IN THE UPPER 40S/LOW 50S ARE ON DECK
FOR SUNDAY, WITH GUSTS AROUND 20-25 MPH POSSIBLE. WINDS WILL
DIMINISH BY TOMORROW EVENING, WITH CLEAR AND QUIET WEATHER TO
CLOSE THE WEEKEND.
THE FORECAST TAKES A MUCH WETTER TURN TO OPEN THE WORK WEEK. A
NEGATIVELY-TILTED SHORTWAVE TROUGH IS PROGGED TO KICK NORTHEAST FROM
THE DESERT SOUTHWEST INTO THE CENTRAL GREAT PLAINS BY MIDDAY MONDAY.
STRONG ASCENT EAST OF THE SHORTWAVE WILL SPAWN A SURFACE LOW ACROSS
CENTRAL TEXAS MONDAY MORNING, WITH A TRAJECTORY TOWARDS THE UPPER
MIDWEST. A PROLONGED FETCH OF GULF MOISTURE WILL YIELD A NEARLY 5
SIGMA PWAT ANOMALY INTO THE UPPER MIDWEST BY MONDAY EVENING. IN
FACT, THE EXPECTED 1-1.25" PWATS WILL BE NEAR THE
CLIMATOLOGICAL MAXIMUM, POTENTIALLY SETTING A NEW RECORD PER MPX
SOUNDING CLIMATOLOGY. MOISTURE RETURN WILL WORK IN TANDEM WITH
BROAD ISENTROPIC ASCENT TO PRODUCE AN EXPANSIVE SHIELD OF
RAINFALL NORTH OF THE SURFACE LOW, WHICH IS SET TO ARRIVE IN
SOUTHERN MINNESOTA BY MONDAY AFTERNOON. HIGH CONFIDENCE A
PROLONGED PERIOD OF RAINFALL IS REFLECTED BY 90-100% POPS ACROSS
THE ENTIRE AREA MONDAY NIGHT INTO TUESDAY MORNING. THE LATEST
QPF EXPECTATIONS BETWEEN 1-1.5" FOR THE MAJORITY OF COMMUNITIES
REMAINS LARGELY UNCHANGED FROM THE PREVIOUS FORECAST. RAIN WILL
END FROM SOUTH TO NORTH TUESDAY MORNING, AS THE SYSTEMS DRY SLOT
WRAPS IN. EASTERLY WINDS WILL BE THE STRONGEST ACROSS EASTERN
MN/WESTERN WI INITIALLY, FOLLOWED BY AN INCREASE IN
NORTHWESTERLY WINDS ACROSS WESTERN MN ON THE BACKSIDE OF THE
SURFACE LOW TUESDAY AFTERNOON.
THE EVOLUTION OF THE FORECAST BEYOND TUESDAY STILL REMAINS A
SOMEWHAT OF A LOWER CONFIDENCE SITUATION, THOUGH THE RANGE OF
POTENTIAL OUTCOMES IS STARTING TO NARROW. THE STRENGTH OF THE
INTERACTION/PHASE BETWEEN THE UPPER-LEVEL LOW AND AN UPSTREAM TROUGH
WILL SIGNIFICANTLY IMPACT HOW THE FORECAST EVOLVES. AS MENTIONED BY
THE OVERNIGHT SHIFT, THE EURO SUITE GENERALLY FAVORS A MORE
NORTHWARD TRACK OF THE OCCLUDING SURFACE LOW, WHERE AS THE GFS SUITE
IS ON MORE OF A NORTHEASTERLY TRAJECTORY. THE GENERAL EURO/EPS
THEME, WHICH WE'LL CALL SCENARIO #1, WOULD ALLOW FOR COLDER AIR TO
ADVECT IN FROM THE NORTHWEST ON WEDNESDAY, RESULTING IN THE
POTENTIAL FOR A PERIOD OF LIGHT SNOW. SCENARIO #2, DEPICTED BY
THE GFS/GEFS, TAKES MORE OF AN EASTERLY TRACK TOWARDS THE
NORTHERN GREAT LAKES. WHILE THERE WILL STILL BE SOME DEGREE OF
COLD AIR ADVECTION ON THE WESTERN EXTENT OF THE UPPER-LOW, IT
MAY NOT BE ENOUGH TO PRODUCE MUCH IN THE WAY OF WINTRY
PRECIPITATION. THE CANADIAN SUITE LEANS ON THE SIDE OF THE
EUROPEAN, WITH A MORE NORTHWARD TRACK OF THE INITIAL SURFACE
LOW. PUTTING THE PIECES TOGETHER, IT CERTAINLY LOOKS POSSIBLE
FOR LIGHT SNOW TO OCCUR ACROSS THE REGION WEDNESDAY, HOWEVER
AMOUNTS WOULD BE HIGHLY DEPENDENT ON THE DEPTH OF COLD AIR ALOFT
AND WOULD MOST LIKELY NOT BE SIGNIFICANT. A SECONDARY SURFACE
SYSTEM IS FORECAST TO DEEPEN ACROSS THE GREAT LAKES THURSDAY,
THOUGH LATEST TRENDS KEEP THE LOCAL FORECAST AREA DRY WITH ALL
OF THE WRAP AROUND PRECIPITATION ASSOCIATED WITH THAT SYSTEM OFF
TO THE EAST. NORTHWESTERLY FLOW WILL BRING COLDER TEMPERATURES
FOR THE MIDDLE TO END OF NEXT WEEK, WITH HIGHS IN THE 30S AND
LOWS IN THE 20S.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1205 PM CST SAT NOV 16 2024
GUSTY SOUTHEAST WINDS ARE THE MAIN AVIATION STORY TO OPEN THE
18Z TAF PERIOD. VFR CONDITIONS ARE SET TO PREVAIL THROUGH THE
AFTERNOON FOR THE MINNESOTA TERMINALS. MVFR STRATUS IS LIFTING
NORTHWEST IN WESTERN WISCONSIN AND HAS ALREADY REACHED EAU. THE
STRATUS WILL BE SOMETHING TO WATCH CLOSELY AT RNH AND POTENTIALLY
MSP (SEE BELOW) HEADING INTO THIS EVENING. A SURFACE COLD FRONT
WILL MOVE THROUGH FROM WEST TO EAST TONIGHT, WHICH WILL KICK THE
WINDS OUT OF THE WEST HEADING INTO SUNDAY. CONFIDENCE REMAINS
HIGH THAT THE THE FRONTAL PASSAGE WILL NOT PRODUCE PRECIPITATION
AT MOST OF THE TERMINALS, HOWEVER HI-RES GUIDANCE DEPICTS THE
POTENTIAL FOR -SHRA AT EAU. WE HAVE MAINTAINED THE PROB30
BETWEEN 3-7Z AT EAU TO ADDRESS THIS POTENTIAL. WESTERLY WINDS
ARE FORECAST TO GUST BETWEEN 20-25 KTS AFTER DAYBREAK SUNDAY.
KMSP...KEEPING A CLOSE EYE ON SURFACE OBSERVATIONS ACROSS
NORTHEAST IOWA/WESTERN WISCONSIN, AS MVFR STRATUS IS SLOWLY
LIFTING TO THE NORTHWEST. LATEST RAP GUIDANCE HAS TRENDED
OPTIMISTIC AT MSP, SUCH THAT WE'VE OPTED TO ROLL WITH VFR CIGS
THROUGH THE PERIOD. INTRODUCED SCT025/020 TO ILLUSTRATE THE
IDEA OF BRIEF MVFR CONDITIONS UNTIL WINDS SHIFT MORE SW/W AFTER
4/5Z.
/OUTLOOK FOR KMSP/
MON...VFR. WIND SE 10-15KTS.
TUE...MVFR/RA, IFR LIKELY. WIND E 10-15KTS BCMG W 15-20G30 KTS.
WED...MVFR. CHANCE -SHRA/IFR. WIND NW 15G25-30KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...STRUS
AVIATION...STRUS
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