055
FXUS63 KMPX 151654
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1154 AM CDT THU MAY 15 2025
KEY MESSAGES
- INITIAL THUNDERSTORM COMPLEX MOVES ACROSS CENTRAL/SOUTHERN MINNESOTA
THROUGH DAYBREAK. STORMS ARE FORECAST TO WEAKEN AS THEY MOVE
EAST.
- ENHANCED RISK (LEVEL 3/5) FOR SEVERE WEATHER FROM EASTERN MINNESOTA
THROUGH MOST OF WISCONSIN THIS AFTERNOON. VERY LARGE HAIL,
DAMAGING WINDS, AND TORNADOES ARE ALL POSSIBLE.
- STRONG SOUTHWESTERLY WINDS FOLLOW THE FRONTAL PASSAGE THIS
EVENING AND CONTINUE INTO FRIDAY. WIND ADVISORY ISSUED ACROSS
SOUTHERN MINNESOTA WHERE GUSTS UP TO 50 MPH ARE POSSIBLE.
- COOLER, BELOW NORMAL TEMPERATURES FOR THE WEEKEND. WET WEATHER
RETURNS EARLY NEXT WEEK.
UPDATE
ISSUED AT 1140 AM CDT THU MAY 15 2025
TODAY...STORMS EXPECTED TO DEVELOP BETWEEN 12 AND 1PM ACROSS
WESTERN AND CENTRAL MINNESOTA, LIFTING NORTHEAST THIS AFTERNOON
AND EVENING. LATEST 3HR SBCAPE CHANGE SHOWS AN INCREASE OF ABOUT
1500 J/KG OF INSTABILITY OVER THE MORNING HOURS ACROSS SOUTHWEST
MINNESOTA. THERE IS AN OCCLUDED FRONTAL BOUNDARY THAT
TRANSITIONED TO A WARM FRONT, AND NORTH OF THIS WARM FRONT WAS
A STRATUS DECK WITH LCLS NEAR 1500 FT. THIS STRATUS WAS STARTING
TO TAKE ON A MORE CUMULUS LOOK IN THE LATEST SATELLITE IMAGERY,
AND HIRES MODELS SHOW THIS AS THE AREA OF INITIATION SHORTLY.
THE FORECAST PARAMETERS THAT SUPPORT SEVERE WEATHER ARE STRONG
FORCING ALOFT, AND A FAVORABLE LOW LEVEL WIND PROFILE WITH
LARGE CURVED HODOGRAPHS. THIS IS THE MAIN CONCERN WITH REGARDS
TO THE TORNADO THREAT.
THE FORECAST PARAMETERS THAT ARE NOT SUPPORTIVE ARE THE HIGHER
CLOUD BASES NORTH OF THE BOUNDARY, AND THE FACT THAT STORMS WILL
BE MOVING ACROSS A NARROW RIBBON OF INSTABILITY. ALSO THE MID
AND UPPER LEVEL WIND ARE WEAK (THOUGH DIVERGENT AHEAD OF THE
UPPER LEVEL WAVE).
FOR THOSE REASONS, ANTICIPATE STORMS DEVELOPING QUICKLY GIVEN
THE STRONG FORCING. THE MAIN TORNADO THREAT LOOKS TO BE SHORTLY
AFTER INITIATION AS THE STORMS ARE ABLE TO TAP INTO AN
ENVIRONMENT WITH LOWER LCLS, AND STILL REMAIN DISCRETE. HOWEVER
SINCE THEY WILL BE MOVING ACROSS THE BOUNDARY, THE TORNADOES
SHOULD BE SHORTER-LIVED BUT COULD STILL BE STRONG, AS INDICATED
BY THE SHORT, YET ISOLATED HIGHER AMOUNTS OF UPDRAFT HELICITY.
THIS WOULD BE EARLY THIS AFTERNOON IN MINNESOTA, AND MID TO LATE
AFTERNOON IN WISCONSIN. STEEP MID LEVEL LAPSE RATES WOULD
SUPPORT LARGE HAIL, AND THE DAMAGING WIND COMPONENT WILL DEVELOP
AFTER THE STORMS FORM INTO A LINE, WITH POTENTIAL FOR A QLCS
AND AREAS OF EMBEDDED ROTATION.
DISCUSSION
ISSUED AT 158 AM CDT THU MAY 15 2025
SEVERE WEATHER POSSIBLE TODAY...REGIONAL RADAR CAPTURES ROBUST
CONVECTION ONGOING ACROSS SOUTHEASTERN SD/NORTHEASTERN NE. THE
STRONGEST ACTIVITY WAS LOCATED ON THE NOSE OF THE INSTABILITY
GRADIENT OVER NORTHEASTERN NE. AS ANTICIPATED, UPSCALE GROWTH INTO A
MATURE MCS IS UNDERWAY. WE'VE DISCUSSED THE POTENTIAL OUTCOMES IN
THE TRACK OF THIS COMPLEX OVER THE PAST FEW DISCUSSIONS. HREF'S CAM
ENSEMBLE HAS COME INTO PRETTY SOLID AGREEMENT THAT THE MCS WILL MOVE
INTO SOUTHWESTERN MINNESOTA AND CONTINUE ON A MORE NORTHEASTERLY
TRACK SUPPORTED BY THE MID TO UPPER LEVEL FLOW. EVEN AT THIS NEAR
TERM/NOWCAST FORECAST DISTANCE, IT STILL SEEMS CONCEIVABLE THAT THE
MCS TAKES A LITTLE BIT OF AN EASTERLY TURN ALONG THE INSTABILITY
GRADIENT, WHICH KEEPS AREAS LIKE THE TC METRO IN PLAY FOR CONVECTION
THROUGH MID-MORNING. THIS SCENARIO IS DISPLAYED BY THE 00Z RRFS.
ISOLATED DAMAGING WIND GUSTS AND LARGE HAIL ARE POSSIBLE AS THE
COMPLEX MOVES ACROSS SOUTHWEST MN, THOUGH WE DO EXPECT THE MCS TO
GRADUALLY DECAY AS MOVES EAST WITH TIME.
THE QUICK TRANSLATION OF A NEGATIVELY TILTED TROUGH OVER THE EASTERN
DAKOTAS WILL SUPPORT THE DEEPENING OF A CLIMATOLOGICALLY ANOMALOUS
~980S MB SURFACE LOW NEAR THE ND/SD/MN TRIPLE POINT. THE OCCLUSION
OF THE SURFACE CYCLONE WILL SEND AN ELONGATED COLD FRONT RAPIDLY
ACROSS MINNESOTA, WHICH WILL BE THE FOCUS FOR A POTENTIAL SEVERE
WEATHER EPISODE THIS AFTERNOON. AN EML, CHARACTERIZED BY A NARROW
PLUME 8-8.5C/KM MID-LEVEL LAPSE RATES, WILL OVERSPREAD SOUTHERN MN
FOLLOWING THE MORNING MCS. THIS WILL EFFECTIVELY WORK TO "CAP" THE
ATMOSPHERE, ALLOWING FOR EXTREME INSTABILITY TO BUILD ALOFT AHEAD OF
THE PRIMARY SEVERE WEATHER THREAT -- THOUGH IT SHOULD BE NOTED THAT
THIS WINDOW WILL LIKELY BE FAIRLY SHORT AS ATTEMPTS AT RENEWED
CONVECTIVE INITIATION ARE EXPECTED ACROSS EASTERN MN AS EARLY AS
LATE MORNING. ELEVATED CONVECTION NEAR THE SURFACE LOW WILL LIKELY
BE ONGOING ACROSS WESTERN/CENTRAL MN THROUGH THE MID-MORNING HOURS.
THERE COULD BE A FEW INSTANCES OF LARGE HAIL IN THIS CONVECTION,
HOWEVER THE GREATER THREAT OF SEVERE WEATHER WILL EXIST TO THE SOUTH
AND EAST. WHILE CLOUD DEBRIS FROM THE MORNING MCS/SLOW-TO-CLEAR
PRECIPITATION MAY PLAY A FACTOR IN THE EVENTUAL OUTCOME OF TODAY'S
SETUP, THERE IS HIGH CONFIDENCE THAT A RATHER VOLATILE ENVIRONMENT
CAPABLE OF PRODUCING ALL SEVERE WEATHER HAZARDS WILL TAKE SHAPE OVER
EASTERN MN/WESTERN WI BY LATE MORNING. A QUICK HIGHLIGHT OF THE
EXPECTED ENVIRONMENT ACROSS EASTERN MN/WESTERN WI INCLUDES MLCAPES
OF 2500+ J/KG (SUPPORTING ROBUST UPDRAFTS), MODESTLY STEEP MID-LEVEL
LAPSE RATES, SHIP VALUES BETWEEN 2.0-2.5 (INDICATES THE POTENTIAL
FOR SIGNIFICANT HAIL IN EXCESS OF 2"), ALONG WITH STRONG SHEAR.
CONVECTIVE MODE WILL BE A KEY PLAYER IN THE OCCURRENCE OF ANY SINGLE
HAZARD, BUT THIS TYPE OF ENVIRONMENT IS CAPABLE OF PRODUCING VERY
LARGE HAIL (2"+), DAMAGING WINDS (60+ MPH) AND TORNADOES (PERHAPS A
FEW STRONG TORNADOES). SPC MADE LITTLE CHANGE TO THE NEW DAY 1
OUTLOOK, AS FAR EASTERN MN AND ALL OF WESTERN WI REMAINING UNDER THE
ENHANCED RISK (3/5). MUCH OF THE REMAINING REAL ESTATE ACROSS THE
MPX COVERAGE AREA (CENTRAL/SOUTHERN MN) ARE UNDER THE SLIGHT RISK
(LEVEL 2/5).
THE THREAT ACROSS THE SLIGHT RISK AREA IS SOMEWHAT CONDITIONAL DUE
TO THE CAPPING AND QUICK TURNAROUND FROM THE MORNING CONVECTION,
WHICH MAY IN TURN LIMIT STORM COVERAGE. HOWEVER, CAMS CONTINUE TO
DISPLAY AN ARC OF ROBUST CONVECTION DEVELOPING BY EARLY AFTERNOON
ACROSS EAST CENTRAL MN SOUTHEAST INTO WESTERN WI. GIVEN THE
AFOREMENTIONED ENVIRONMENT AND STRONG SYNOPTIC SUPPORT, WOULD EXPECT
CONVECTION TO INTENSIFY QUICKLY. ESSENTIALLY THE ENHANCED RISK
SERVES AS THE AREA BY WHICH WIDESPREAD COVERAGE OF NUMEROUS SEVERE
THUNDERSTORMS ARE EXPECTED. SO WHILE ALL HAZARDS ARE POSSIBLE WITH
ANY STORMS THAT DEVELOP TODAY, THE GREATEST PROBABILITIES EXIST
ACROSS FAR EASTERN MN/WESTERN WI. ANOTHER ITEM TO WATCH WILL BE THE
UPSCALE EVOLUTION OF CONVECTION AS MATURES WITH EASTWARD MOVEMENT
INTO WI THIS AFTERNOON. SHOULD STORMS GROW INTO LINEAR SEGMENTS, A
MORE PRONOUNCED DAMAGING WIND THREAT MAY MATERIALIZE. CONVERSELY,
SHOULD SUPERCELLS REMAIN SEMI-DISCRETE, A GREATER TORNADO SCENARIO
IS ON THE TABLE. SPC HAS HIGHLIGHTED A LARGE SWATH OF WEST/CENTRAL
WI UNDER THE 10% SIG HATCHED AREA OF TORNADOES. CONVECTION WILL BE
MOVING QUICKLY GIVEN THE STRONG FLOW ALOFT, SO WE'LL BE ABLE TO GIVE
A HIGH CONFIDENCE "ALL CLEAR" FROM SOUTHWEST TO NORTHEAST WITH TIME
THIS AFTERNOON. TODAY IS NOT A "SLAM DUNK" SEVERE WEATHER DAY IN THE
TWIN CITIES GIVEN THE CONDITIONAL NATURE OF STORM COVERAGE, BUT IT
IS A DAY TO RESPECT THE SETUP AND BE READY TO RESPOND TO
WATCH/WARNING INFORMATION SHOULD SEVERE THUNDERSTORMS DEVELOP.
STRONG WINDS THIS EVENING/FRIDAY...SHORTLY AFTER THE DEPARTURE OF
CONVECTION, A "STING JET" SCENARIO AIMS TO SETUP ACROSS THE REGION.
THE TRANSLATION OF THE 700MB JETSTREAK AROUND THE UPPER-LOW WILL
DRIVE STRONG SOUTHWESTERLY WINDS TO THE SURFACE WITH GUSTS UP TO 50
MPH THIS AFTERNOON AND EVENING. WE'LL OBSERVE AN INCREASE IN WINDS
ACROSS THE ENTIRE REGION AS THIS PROCESS OCCURS, BUT IT'S SOUTH-
CENTRAL MINNESOTA WHERE THE FORECAST OF STRONGEST WINDS HAS PROMPTED
THE ISSUANCE OF A WIND ADVISORY. STRONG WINDS (45+ MPH), LINGERING
DEFORMATION PRECIPITATION, AND COOLER TEMPERATURES WILL MAKE FOR A
RATHER RAW DAY TOMORROW. THE POTENT SPRING STORM SYSTEM WILL BEGIN
TO DEPART SATURDAY, THOUGH IT WILL STILL BE BREEZY AND COOL WITH
HIGHS IN THE 50S. TEMPERATURES THEN CLIMB INTO THE 60S SUNDAY &
BEYOND, WITH THE RETURN OF RAIN CHANCES EARLY NEXT WEEK. LATEST NBM
ALREADY FEATURES 80%+ POPS IN THE TUESDAY TIMEFRAME...WHICH IS
REFLECTIVE OF NEARLY ALL ENSEMBLE MEMBERS DISPLAYING PRECIPITATION.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 631 AM CDT THU MAY 15 2025
A VERY COMPLEX TAF PERIOD WEATHER-WISE IS UNFOLDING, WITH TWO
ROUNDS OF STORMS LIKELY, FOLLOWED BY STRONG WINDS BEHIND A COLD
FRONT THURSDAY AFTERNOON. THE FIRST ROUND OF STORMS MOVING
ACROSS WESTERN/SOUTHERN MN, SLIDING SLOWLY EASTWARD, WILL RUN
INTO A SLIGHTLY MORE STABLE AIRMASS AND ITS PROGRESSION IS
EXPECTED TO CONTINUE SLOWING WITH THE LINE GRADUALLY
DISSIPATING. HOWEVER, THIS WILL LEAD TO THE CONTINUED
UNCERTAINTY SURROUNDING THE SECOND ROUND OF CONVECTION FOR LATER
THIS AFTERNOON-EVENING. ROUND 2 IS STILL EXPECTED TO DEVELOP
OVER CENTRAL-EASTERN MN ALONG A COLD/OCCLUDED SURFACE FRONT.
WHILE RWF/AXN HAVE BEEN IN THE CROSSHAIRS OF THIS FIRST ROUND,
RWF/AXN/MKT ARE THE MOST LIKELY TO MISS THE SECOND ROUND. THE
ISSUE FOR THOSE SITES WILL BE VERY STRONG WINDS ON THE BACKSIDE
OF THE FRONT. FOR THE REMAINING TAF SITES, CONVECTION IN THE
SECOND ROUND LOOKS FAIRLY GOOD TO IMPACT THOSE SITES, WITH
CONDITIONS AT A MINIMUM GETTING DOWN TO MVFR, THOUGH HEAVY RAIN
COULD/WOULD PUSH VISIBILITIES INTO IFR. CONDITIONS GENERALLY
IMPROVE OVERNIGHT BEHIND THE EVENING ACTIVITY, BUT WRAP-AROUND
MOISTURE COMING INTO THE REGION TOMORROW WILL LEAD TO STEADY
RAINFALL, WHICH HAS BEEN INCLUDED IN THE WESTERN TAF SITES
STARTING JUST PRIOR TO DAYBREAK FRIDAY.
KMSP...WILL MONITOR IF THE DIMINISHING LINE OF CONVECTION
ACTUALLY MAKES IT TO MSP BUT CONFIDENCE IS PRETTY LOW AT THIS
POINT SO HAVE OMITTED ITS MENTION AT INITIALIZATION. BEST TIMING
FOR ACTIVITY LATER ON TO REACH MSP LOOKS TO BE 18Z-21Z, ALTHOUGH
STORM DURATION AT MSP WILL ACTUALLY LAST MUCH LESS THAN THAT 3
HOUR WINDOW, MORE LIKELY 30-45 MINUTES. THE NEXT ISSUE BECOMES
STRONG WINDS BEHIND AN ANTICIPATED ARCING LINE OF THUNDERSTORMS,
PRODUCING STRONG CROSSWINDS. DIRECTIONS OF 200-220 WITH SPEEDS
NEAR 20G30KTS (POSSIBLY AS HIGH AS 35-40KTS) WILL CAUSE SOME
CROSSWIND ISSUES FOR THE NORTH PARALLEL.
/OUTLOOK FOR KMSP/
SAT...MVFR MRNG CIGS LIKELY. WIND NW 10-15G20-25 KTS.
SUN...VFR. WIND NE 5-10 KTS.
MON...MAINLY VFR. CHANCE MVFR/SHRA. WIND ESE 10-15G25KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...WIND ADVISORY UNTIL 9 PM CDT THIS EVENING FOR BLUE EARTH-BROWN-
CHIPPEWA-FARIBAULT-FREEBORN-LAC QUI PARLE-LE SUEUR-MARTIN-
NICOLLET-REDWOOD-RENVILLE-SIBLEY-STEELE-WASECA-WATONWAN-
YELLOW MEDICINE.
WI...NONE.
UPDATE...JRB
DISCUSSION...STRUS
AVIATION...JPC
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