128
FXUS63 KMPX 150644
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
144 AM CDT TUE OCT 15 2024
KEY MESSAGES
- COLDEST MORNING OF THE FALL SEASON TO DATE. WIDESPREAD SUB-
FREEZING TEMPERATURES SIGNAL THE END OF THE GROWING SEASON.
- INCREASING FIRE WEATHER CONCERNS WEDNESDAY ONWARD, AS WARM, DRY,
AND WINDY CONDITIONS RETURN.
- WEEKEND TRENDING WARMER AND DRIER THAN PREVIOUS FORECASTS.
DISCUSSION
ISSUED AT 135 AM CDT TUE OCT 15 2024
EARLY MORNING GOES SATELLITE IMAGERY REVEALS MOSTLY CLEAR SKIES
ACROSS MOST OF THE AREA. THERE ARE A FEW LINGERING CLOUDS ASSOCIATED
WITH LINGERING SPRINKLES IN WESTERN MINNESOTA, AS WELL AS BROKEN
STRATUS ACROSS WESTERN WISCONSIN. TEMPERATURES HAVE ALREADY FALLEN
INTO THE MID 30S AND THE EXPECTATION IS THAT THEY WILL CONTINUE TO
DROP INTO THE UPPER 20S/LOW 30S FOR LOCATIONS OUTSIDE OF THE TWIN
CITIES METRO. LIGHT WINDS AND MOSTLY CLEAR SKIES PAIR WELL WITH THE
APPROACH OF AN EXPANSIVE 1034 MB HIGH TO PROMOTE EFFICIENT
RADIATIONAL COOLING. A FREEZE WARNING CONTINUES ACROSS SOUTH CENTRAL
MINNESOTA, AS THE WIDESPREAD SUB-FREEZING TEMPERATURES WILL
EFFECTIVELY END THE GROWING SEASON. THE EFFICIENT COOLING BRINGS THE
CHANCE THAT TEMPERATURES WILL FALL TOWARDS THE DEW POINT PRIOR TO
DAYBREAK, WHICH MAY RESULT IN THE DEVELOPMENT OF PATCHY FOG. RAP
FORECAST SOUNDINGS TEND TO CAPTURE THIS SCENARIO, PARTICULARLY
ACROSS CENTRAL MINNESOTA WHERE THE AIR TEMPERATURE FORECAST IS THE
LOWEST. ANY FOG WILL MIX OUT THIS MORNING, REVEALING SUNNY, QUIET,
AND COOL CONDITIONS FOR TUESDAY. AFTERNOON HIGHS REMAIN WELL BELOW
NORMAL, IN THE LOW 50S, GIVEN THE COOL AIRMASS OVERHEAD. THE
INFLUENCE OF THE SURFACE HIGH WILL SUPPORT ANOTHER CHILLY NIGHT AND
ANY LOCATIONS THAT DO NOT OBSERVE SUB-FREEZING TEMPERATURES THIS
MORNING WILL LIKELY ACHIEVE A FREEZE TONIGHT.
THE FORECAST IS ON TRACK TO TAKE A TURN IN A WARMER DIRECTION ON
WEDNESDAY, AS A ~570 DM RIDGE BUILDS OVER THE REGION. MID-LEVEL FLOW
AND THERMAL ADVECTION WILL INCREASE OUT OF THE SOUTHWEST BY THE
AFTERNOON AND SURFACE HIGH TEMPERATURES ARE FORECAST TO CLIMB INTO
THE LOW TO MID 60S. THE ARRIVAL OF A TROUGH ACROSS THE WESTERN
PORTION OF THE CONUS WILL PUSH THE RIDGE AXIS EAST OF MINNESOTA AND
WISCONSIN BY THURSDAY, SUCH THAT THE UPPER MIDWEST WILL BE IN PRIME
POSITION FOR STRONG LARGE SCALE WARM ADVECTION (GUIDANCE SUGGESTS
850 MB TEMPERATURES WILL APPROACH 15-17C ACROSS SOUTHERN
MINNESOTA!). SURFACE TEMPERATURES ARE FORECAST TO REACH THE UPPER
60S/LOW 70S ON THURSDAY AND CONTINUE TO THE UPWARD TRAJECTORY
FRIDAY, WITH HIGHS RUNNING 10-15 DEGREES ABOVE NORMAL IN THE 70S.
UNFORTUNATELY, THE WARMER TEMPERATURES WILL RESULT IN DRIER RELATIVE
HUMIDITY VALUES AND THE COMBINATION OF VERY DRY AIR, GUSTY
SOUTHWESTERLY WINDS, AND DRY FUELS AIMS TO CREATE A FAVORABLE SETUP
FOR ELEVATED FIRE WEATHER CONCERNS LATER THIS WEEK.
PERHAPS THE BIGGEST TREND IN THE FORECAST THIS MORNING IS FOR A
DRIER AND WARMER WEEKEND. GUIDANCE REMAINS STEADY ON THE IDEA THAT
AN UPPER LOW AT THE BASE OF THE WESTERN TROUGH WILL BECOME CUTOFF
NEAR THE FOUR CORNERS REGION. THIS SCENARIO MEANS WEAKER FLOW
AND FORCING ACROSS THE NORTHERN CONUS HEADING INTO THE WEEKEND.
WE STILL ANTICIPATE THAT A FRONTAL BOUNDARY ALONG A BAROCLINIC
ZONE WILL MOVE ACROSS THE REGION FRIDAY NIGHT INTO SATURDAY,
HOWEVER THE LACK OF NOTABLE FORCING WILL MEAN LESS IN WAY OF
EXPECTED QPF. MOISTURE RETURN ISN'T THE ISSUE, AS A PLUME OF
PWATS ~1" WILL EXTEND FROM THE GULF NORTHWARD INTO THE UPPER
MIDWEST. THE PROBLEM IS THAT THE MOISTURE IS CONTAINED TO THE
UPPER LEVELS IN FORECAST SOUNDINGS AND WILL NOT BE CONVERTED
INTO MUCH IN THE WAY OF WIDESPREAD PRECIPITATION GIVEN THE LACK
OF FORCING. MULTI-RUN ENSEMBLE ANALYSIS DEPICTS A DECREASE IN
QPF OVER THE LAST FEW RUNS OF THE EPS AND GEFS. TO MAKE A LONG
STORY SHORT, THE FORECAST FEATURES CHANCE POPS FOR SCATTERED
SHOWERS THIS WEEKEND, THOUGH WE DO NOT EXPECT THOSE SHOWERS TO
PRODUCE MUCH QPF. WITH THE RAINFALL SETUP BECOMING MORE OF A
MUTE POINT, IT'S NOT SURPRISING TO SEE THE TEMPERATURE FORECAST
RESPOND IN A WARMER DIRECTION. BLENDED GUIDANCE HAS RESPONDED TO
THE DRIER TREND WITH HIGHS IN THE UPPER 60S/LOW 70S THROUGH THE
WEEKEND. THIS IS NOT GOOD NEWS FOR THE FIRE WEATHER SITUATION,
WHICH WILL EXTEND THROUGH THE UPCOMING WEEKEND SHOULD THE LOW
QPF TRENDS COME TO FRUITION. GUIDANCE REMAINS UNSETTLED IN THE
EXTENDED PERIOD, WITH PERHAPS A CHANCE FOR PRECIPITATION EARLY
NEXT WEEK. TIME WILL TELL AND FOR NOW IT SEEMS BEST TO LEAN ON
THE DRY SIDE UNTIL PROVEN OTHERWISE.
AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 1239 AM CDT TUE OCT 15 2024
A MID-LEVEL SHORTWAVE IN ADVANCE OF INCOMING HIGH PRESSURE WILL
SPELL MID-LEVEL SCT CLOUD COVERAGE THROUGH THE MIDDLE PORTION OF
THE DAY FOLLOWED BY CLEARING SKIES TONIGHT INTO WEDNESDAY
MORNING. WINDS WILL REMAIN GENERALLY NORTHERLY THROUGH MIDDAY
WITH SPEEDS TOPPING OUT AROUND 10KTS, POTENTIALLY WITH A FEW
GUSTS IN THE 15-20KT RANGE FROM TIME TO TIME, UNDER TONIGHT WHEN
WINDS GO LIGHT/VARIABLE UNDERNEATH THE APPROACHING HIGH PRESSURE
AIRMASS.
KMSP...NO ADDITIONAL CONCERNS.
/OUTLOOK FOR KMSP/
THU-FRI...VFR. WIND S 15-20G25-35KTS.
SAT...VFR. CHC -RA EARLY. WIND SW 5-10KTS.
SUN...VFR. WIND SW 5-10KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...FREEZE WARNING UNTIL 9 AM CDT THIS MORNING FOR BLUE EARTH-
BROWN-CARVER-CHIPPEWA-DAKOTA-DOUGLAS-FARIBAULT-FREEBORN-
GOODHUE-HENNEPIN-KANDIYOHI-LAC QUI PARLE-LE SUEUR-MARTIN-
MCLEOD-MEEKER-NICOLLET-POPE-RAMSEY-REDWOOD-RENVILLE-RICE-
SCOTT-SIBLEY-STEARNS-STEELE-STEVENS-SWIFT-TODD-WASECA-
WATONWAN-WRIGHT-YELLOW MEDICINE.
WI...NONE.
DISCUSSION...STRUS
AVIATION...JPC
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