058
FXUS63 KMPX 270400
AFDMPX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
1100 PM CDT SAT APR 26 2025
KEY MESSAGES
- SHOWERS AND A FEW THUNDERSTORMS LATE TONIGHT AND EARLY SUNDAY.
- THUNDERSTORMS REDEVELOP SUNDAY NIGHT INTO MONDAY MORNING. SOME
STORMS MAY BE SEVERE WITH LARGE HAIL AS THE PRIMARY HAZARD.
- AN OUTBREAK OF SEVERE WEATHER POSSIBLE ACROSS SOUTHERN/EASTERN
MN AND WI MONDAY AFTERNOON AND EARLY EVENING. A LEVEL 4 OUT OF
5 SEVERE RISK REMAINS IN PLACE ACROSS THIS PORTION OF THE
REGION. ALL SEVERE HAZARDS ARE POSSIBLE, INCLUDING STRONG
TORNADOES.
DISCUSSION
ISSUED AT 324 PM CDT SAT APR 26 2025
SHORT TERM (THROUGH SUNDAY AFTERNOON)...
OUR BEAUTIFUL SATURDAY WEATHER CONTINUES THIS AFTERNOON, WITH
TEMPERATURES WARMING INTO THE LOW TO MID 60S FOR HIGHS.
SATELLITE REVEALS INCREASING CLOUD COVER MOVING EAST OUT OF THE
DAKOTAS, WHICH IS IN RESPONSE TO INCREASING MOISTURE RETURN
BEHIND THE DEPARTING AREA OF SURFACE HIGH PRESSURE OVER THE
GREAT LAKES. MOISTURE ADVECTION WILL CONTINUE TO INCREASE
TONIGHT BY WAY OF A 40+ KNOT LOW-LEVEL JET FORECAST TO TILT FROM
SOUTHWEST TO NORTHEAST ACROSS THE DAKOTAS INTO NORTHWEST
MINNESOTA. HI-RES GUIDANCE CONTINUES TO DEPICT THE DEVELOPMENT
OF A BAND OF SHOWERS AND A FEW THUNDERSTORMS AHEAD OF THE LOW-
LEVEL JET, WHICH WILL MOVE FROM WEST TO EAST OVERNIGHT. NO
SEVERE WEATHER IS EXPECTED THROUGH TOMORROW MORNING. FOLLOWING
THE CONCLUSION OF THE MORNING ACTIVITY, THE FORECAST WILL TREND
ON THE DRIER SIDE TOMORROW. WE CANNOT RULE OUT A FEW SHOWERS OR
THUNDERSTORMS WITHIN THE SOUTHWESTERLY MID-LEVEL FLOW, THOUGH
COVERAGE WOULD APPEAR TO BE RELATIVELY LIMITED. TEMPERATURES
CLIMB INTO THE MID TO UPPER 60S, WITH BREEZY SOUTHEASTERLY
SURFACE WINDS GUSTING BETWEEN 20-30 MPH.
**HISTORICAL NOTE -- THE STORM PREDICTION CENTER INTRODUCED A
DAY 3 MODERATE RISK ACROSS SOUTHEAST MINNESOTA, WESTERN
WISCONSIN, AND NORTHEAST IOWA EARLIER TODAY. THIS IS THE FIRST
SUCH OCCURRENCE ACROSS THE NWS TWIN CITIES FORECAST AREA SINCE
APRIL 8, 2011**
SUNDAY PM/MONDAY AM: ROUND #1 OF POTENTIAL SEVERE WEATHER...
WATER VAPOR IMAGERY CAPTURES AN UPPER-LOW COMING ASHORE OVER THE
CALIFORNIA COAST THIS AFTERNOON. BY TOMORROW EVENING, THE
UPPER-LEVEL LOW IS FORECAST TO HAVE MOVED EAST AND BE LOCATED
OVER FOUR CORNERS REGION OF THE SOUTHWEST CONUS. THE UPPER-LEVEL
LOW IS THEN FORECAST TO EJECT NORTHEAST ACROSS THE NORTHERN
PLAINS, BECOMING A POSITIVELY TILTED ELONGATED TROUGH WILL BE
THE MAIN DRIVER OF OUR EXPECTED SEVERE WEATHER EPISODE ON
MONDAY. SURFACE LOW PRESSURE IS FORECAST TO DEVELOP ACROSS THE
DAKOTAS AHEAD OF THE ADVANCE OF THE UPPER-LOW. A STRONG 50+ KNOT
LOW-LEVEL JET WILL EXPAND NORTHEAST OUT THE CENTRAL PLAINS
TOMORROW EVENING AND WILL BE THE FOCUS FOR THE FIRST ROUND OF
POTENTIAL SEVERE WEATHER. CAPPING EVIDENT ON FORECAST SOUNDINGS
SHOULD LIMIT CONVECTIVE DEVELOPMENT THROUGH MUCH OF SUNDAY
EVENING. LATER ON (OR EARLY DEPENDING ON HOW YOU LOOK AT IT),
CONVECTION IS FORECAST TO BLOSSOM ON THE NOSE OF THE LOW-LEVEL
JET. WE'RE JUST STARTING TO ENTER THE WINDOW WHERE A OF THE
LONGER RANGE CAMS ARE ABLE TO RESOLVE AND SIMULATE THIS
CONVECTIVE MODE, WHICH SHOULD TAKE THE LOOK OF AN LINE OF
CONVECTION DEVELOPING ACROSS SOUTHERN MINNESOTA, SET TO LIFT
FROM SOUTHWEST TO NORTHEAST THROUGH DAYBREAK. WHILE THIS ISN'T
GOING TO BE THE "MAIN SHOW" WE ENCOURAGE FOLKS NOT TO SLEEP ON
THIS ROUND OF CONVECTION. STEEP LAPSE RATES AND SUFFICIENT SHEAR
WILL COMBINE TO SUPPORT STRONG ELEVATED CONVECTION CAPABLE OF
PRODUCING LARGE HAIL. DAMAGING WIND GUSTS ARE ALSO POSSIBLE.
CONVECTION MAY MAINTAIN INTENSITY HEADING INTO THE MORNING
COMMUTE, BEFORE DEPARTING TO THE NORTH/NORTHEAST. SPC HAS
EXPANDED THE DAY 2 (THRU 12Z MONDAY) RISK AREA EAST TO REFLECT
THIS POTENTIAL.
MONDAY PM: ROUND #2 - POTENTIAL SEVERE WEATHER OUTBREAK...
A STOUT EML (CHARACTERIZED BY ~9.0C/KM LAPSE RATES) WILL OVERSPREAD
MUCH OF THE REGION FOLLOWING THE MORNING ROUND OF CONVECTION. THIS
WILL ACT AS A CAP, ALLOWING STRONG INSTABILITY TO BUILD WITHIN A
BROAD WARM SECTOR RICH WITH HIGH THETA-E AIR. THE EXPECTED QUICK
TRANSLATION OF STRONG (70-80 KT) 500MB JET STREAK AND ASSOCIATED
850MB FLOW WILL PUSH A WARM FRONT ACROSS THE AREA BY MONDAY
AFTERNOON. BOUNDARY LAYER RECOVERY AND QUICK DESTABILIZATION IS
EXPECTED FOLLOWING THE MORNING ROUND OF CONVECTION, GIVEN THE POTENT
DYNAMICS IN PLAY. GUIDANCE PLACES THE POSITION OF THE SURFACE LOW
ACROSS WEST-CENTRAL MINNESOTA BY EARLY AFTERNOON, WITH A TRAILING
COLD FRONT NEAR THE MN/SD BORDER. AHEAD OF THE FRONT, GUIDANCE
ILLUSTRATES AN ENVIRONMENT THAT IS VERY FAVORABLE FOR SEVERE
WEATHER: 1500+ J/KG OF MLCAPE, STEEP LAPSE RATES IN EXCESS OF
7.5C/KM), DEEP LAYER SHEAR IN EXCESS OF 60+ KNOTS, LOW-LEVEL
CURVATURE TO THE HODOGRAPHS, SURFACE TEMPERATURES IN THE MID 70S TO
LOW 80S, AND DEW POINTS BETWEEN 60-65F. FORECAST GUIDANCE DISPLAYS
THE CLASSIC SEVERE WEATHER "LOADED GUN" SOUNDINGS (MOIST LAYER UP TO
ABOUT ~5K FEET JUST BELOW A STRONG CAPPING INVERSION). WHEN PAIRED
WITH STRONG SHEAR, AS IS FORECAST MONDAY, THIS ENVIRONMENT IS PRIMED
FOR ROBUST CONVECTION.
AS FOR THE CONVECTIVE EVOLUTION, THERE ARE A FEW REGIMES IN PLAY:
1) THE TRANSLATION OF THE JET STREAK MAY PRODUCE SEVERAL SEMI-
DISCRETE SUPERCELLS (CAPABLE OF ALL SEVERE WEATHER HAZARDS,
INCLUDING STRONG TORNADOES) ACROSS THE WARM SECTOR MONDAY
AFTERNOON. THE EARLY READ WITHIN THE EXTENDED CAM GUIDANCE IS
THAT COVERAGE MAY REMAIN SOMEWHAT MUTED OWING TO THE CAPPING
INVERSION REFERENCED ABOVE, HOWEVER THIS SEEMS A BIT UNDERDONE
GIVEN THE STRONG UPPER-LEVEL FORCING THAT IS IN PLAY
(PARTICULARLY THE DEEP ELONGATED TROUGH/FORCING). THE CURRENT
FORECAST FEATURES THE EXPECTED DEVELOPMENT OF SCATTERED SEMI-
DISCRETE SUPERCELLS ACROSS THE OPEN WARM SECTOR CAPABLE OF
PRODUCING STRONG TORNADOES. CONFIDENCE IS HIGHEST IN THIS
DEVELOPMENT (AND ASSOCIATED THREATS) ACROSS SE MN/WESTERN WI AND
HAS PROMPTED THE MODERATE RISK.
2) THE TRAILING COLD FRONT WILL SLIDE FROM WEST TO EAST ACROSS
THE REGION MONDAY EVENING. CONVECTION SHOULD BEGIN TO DEVELOP
ACROSS WESTERN MN AHEAD OF THE FRONT MONDAY AFTERNOON AND
INCREASE IN COVERAGE WITH EASTWARD EXTEND. SEVERAL CLUSTERS OR
SEGMENTS OF STORMS WILL LIKELY GROW UPSCALE INTO A QLCS AS THE
EVENT UNFOLDS. ALL HAZARDS WILL STILL BE POSSIBLE, INCLUDING
BRIEF TORNADOES, AS THE LINE OF CONVECTION MOVES THROUGH. IN
OTHER WORDS, SOME COMMUNITIES ACROSS THE WARM SECTOR MAY BE IN
FOR MULTIPLE ROUNDS OF SEVERE WEATHER WITHIN THE MONDAY
AFTERNOON/EVENING TIMEFRAME.
AS WITH ANY FORECAST, THERE ARE AREAS OF UNCERTAINTY THAT REMAIN ~48
HOURS OUT FROM A CONVECTIVE EVENT. HOWEVER, THE PROS FOR AN OUTBREAK
OF SEVERE WEATHER SIGNIFICANTLY OUTWEIGH THE CONS WITH THIS
PARTICULAR SETUP. THERE HAS BEEN A STRONG SIGNAL ACROSS ML GUIDANCE
SINCE EARLY THIS WEEK AND THE SIGNAL HAS ONLY GROWN MORE CONCERNING
WITH TIME. IN FACT, THE CSU/NCAR ML TOOLS HAVE CONTINUED TO TREND
UPWARDS, WHICH LEADS TO INCREASING CONFIDENCE IN A SIGNIFICANT
SEVERE WEATHER EVENT ACROSS THE UPPER MIDWEST MONDAY. THE ISSUANCE
OF THE DAY 3 MODERATE (LEVEL 4/5) RISK ACROSS SE MN/WESTERN WI
CAPTURES THE RARE AND DANGEROUS NATURE OF THE EXPECTED SETUP
FOR SEVERE THUNDERSTORMS CAPABLE OF PRODUCING ALL HAZARDS. NOW
IS THE TIME TO REVIEW SEVERE WEATHER SAFETY PLANS AND KNOW WHAT
TO DO IF/WHEN SEVERE WEATHER WATCHES AND WARNINGS ARE ISSUED.
EXTENDED PERIOD...
HIGH PRESSURE RETURNS TUESDAY, WHICH WILL SIGNAL DRY WEATHER AND
COOLER TEMPERATURES (50S) BEHIND THE PASSAGE OF THE POTENT STORM
SYSTEM. HOWEVER, THE UNSETTLED NORTHERN STREAM AIMS TO SEND THE NEXT
SHORTWAVE ACROSS THE NORTH CENTRAL CONUS DURING THE WEDNESDAY/THURSDAY
TIMEFRAME. TEMPERATURES WILL REBOUND INTO THE UPPER 60S/LOW 70S
AHEAD OF THIS FEATURE. THE PASSAGE OF A COLD FRONT WILL BRING
THE CHANCE FOR SCATTERED SHOWERS AND PERHAPS A FEW THUNDERSTORMS
THROUGH LATE WEDNESDAY INTO THURSDAY, WHICH IS REFLECTED BY
30-40% POPS IN THE LATEST NBM. HIGH PRESSURE RETURNS TO CLOSE
THE WORK WEEK, PRIOR THE EXPANSION OF A ~570DM RIDGE OVER THE
CENTRAL CONUS LATE NEXT WEEKEND AND BEYOND. GLOBAL GUIDANCE
DEPICTS THE EVOLUTION OF THE UPPER-AIR PATTERN INTO A CLASSIC
OMEGA BLOCK, WHICH SHOULD YIELD MUCH WARMER INTO THE FIRST
PORTION OF MAY.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1049 PM CDT SAT APR 26 2025
MAIN CHANGE TO THE TAFS THIS EVENING IS THE RAIN OVER WESTERN MN
HAS BEEN STRUGGLING WITH THE ANTECEDENT DRY AIRMASS. AS A
RESULT, HAVE DELAYED THE RAIN ONSET AT MOST LOCATIONS AND EVEN
REMOVED IT FROM EAU. WE'RE STILL ANTICIPATING SCATTERED SHOWERS
TO MOVE EAST THROUGH THE NIGHT, THOUGH COVERAGE OF WHAT ACTUALLY
REACHES THE GROUND MAY END UP BEING LESS THAN ORIGINALLY
THOUGHT. NOT MUCH AS CHANGED WITH THOUGHTS FOR SUNDAY, WITH A
STOUT INVERSION BUILDING IN AS MOISTURE SURGES INTO WESTERN MN,
WHERE MVFR CIGS ARE EXPECTED, LIKELY TRENDING TOWARD IFR BY THE
END OF THE PERIOD. ALSO HAPPENING AT THE END OF THE PERIOD IS A
50 KT LLJ WILL START NOSING UP INTO SOUTHERN MN, WHICH WILL
BRING THE TREAT FOR THUNDERSTORMS OVERNIGHT. THIS THUNDER
THREAT LOOKS TO BE JUST GETTING GOING AS WE HIT THE END OF THIS
TAF PERIOD FOR THE 24 HOUR TAFS (6Z MON), WITH CIGS ALSO
DROPPING AS THE WARM FRONT BEGINS ITS TREK TO THE NORTH ACROSS
THE MPX AREA SUNDAY NIGHT.
KMSP...HI-RES MODELS HAVE BEEN TRENDING DRY FOR THE SHOWERS
TRYING TO PUSH EAST TONIGHT, THOUGH WE DO STILL ANTICIPATE A
LITTLE LIGHT RAIN IN THE METRO AROUND SUNRISE. SUNDAY LOOKS
QUIET, WITH MAYBE EVEN SOME PEAKS OF SUN BEFORE MVFR CIGS MOVE
IN PRETTY QUICK SUNDAY EVENING, THAT MAY BE IFR COME MONDAY
MORNING. WITH THE WARM FRONT MOVING ACROSS THE METRO SUNDAY
NIGHT, WE STILL ANTICIPATE FAIRLY WIDESPREAD THUNDERSTORMS TO BE
MOVING NORTH WITH THAT FEATURE, WITH 8Z TO 10Z MONDAY LOOKING
TO CURRENTLY HAVE THE BEST CHANCE OF TS AT MSP.
/OUTLOOK FOR KMSP/
MON...TSRA WITH IFR/MVFR CIGS EARLY, THEN VFR. TSRA REDEVELOPING
IN THE AFTERNOON. WIND S 15-20G30 KTS.
TUE...CHC MVFR CIGS IN THE MORNING. WIND NW 10-20 KTS.
WED...VFR, CHC MVFR/-SHRA LATE. WIND SSE 10-15 KTS.
MPX WATCHES/WARNINGS/ADVISORIES
MN...NONE.
WI...NONE.
DISCUSSION...STRUS
AVIATION...MPG
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