373
FXUS63 KDMX 261750
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
1250 PM CDT SAT APR 26 2025
...UPDATED FOR THE 18Z AVIATION DISCUSSION...
KEY MESSAGES
- VERY PATCHY/TRANSIENT FOG EARLY THIS MORNING NORTH AND WEST.
OTHERWISE DRY TODAY WITH HIGHS IN THE 60S.
- SHOWER AND THUNDERSTORM CHANCES RETURN TONIGHT INTO MONDAY
NIGHT. THERE IS A LOW POTENTIAL FOR STRONG TO SEVERE STORMS
SUNDAY LATE NIGHT, MAINLY NORTHWEST AND WEST.
- MORE WIDESPREAD MODERATE (LEVEL 4 OUT OF 5) RISK FOR SEVERE
WEATHER MONDAY AFTERNOON INTO MONDAY NIGHT WITH ALL HAZARDS
POSSIBLE. DETAILS STILL UNFOLDING SO CONTINUE TO MONITOR THE
FORECAST FOR UPDATES, BUT NOW IS THE TIME TO REVIEW SEVERE
WEATHER PLANS!
DISCUSSION
ISSUED AT 357 AM CDT SAT APR 26 2025
WEAK UPPER LEVEL RIDGING HAS STARTED TO MOVE INTO THE STATE THROUGH
THE OVERNIGHT WITH A SURFACE HIGH BELOW ALSO SETTLING INTO THE
REGION FROM THE NORTH. WITH RESIDUAL SURFACE MOISTURE STILL IN
PLACE, AREAS WHERE WINDS HAVE BECOME LIGHT TO CALM CLOSER TO THE
HIGH IN THE NORTH TO NORTHWEST HAVE STARTED TO SEE HIGHLY TRANSIENT
PATCHY FOG. THIS PATCHY FOG WILL LIKELY CONTINUE AT TIMES UNTIL
AROUND SUNRISE WHEN ANY LINGERING PATCHY FOG SHOULD DISSIPATE. THE
HIGH PRESSURE IN PLACE TODAY WILL KEEP CONDITIONS DRY WITH SKIES
PARTLY TO MOSTLY SUNNY WITH CLOUDS GRADUALLY STREAMING IN FROM THE
WEST THROUGH THE DAY AHEAD OF THE NEXT ACTIVE PERIOD TO END THE
WEEKEND AND START THE NEW WORK WEEK. HIGH TEMPERATURES TODAY WILL
REMAIN A BIT COOLER WITH MID-LEVEL FLOW OUT OF THE NORTH TO EAST,
AND GENERALLY IN THE 60S.
BEHIND THE HIGH PRESSURE AS IT MOVES OFF TO THE EAST TONIGHT,
MOISTURE AND WARM AIR ADVECTION WILL BOTH BE ON THE INCREASE.
BESIDES LEADING TO INCREASING TEMPERATURES INTO SUNDAY, THE WARM AIR
ADVECTION WILL PAIR WITH A WEAK LEADING SHORTWAVE CLIPPING/PASSING
TO THE NORTH SATURDAY NIGHT INTO SUNDAY MORNING AND AN INCREASING 30-
40 KNOT LOW LEVEL JET (LLJ) CENTERED OFF TO THE NORTHWEST TO KICK-
OFF SOME SHOWERS MAINLY NORTH/NORTHWEST OVERNIGHT INTO SUNDAY
MORNING. INSTABILITY REMAINS VERY WEAK INTO SUNDAY MORNING SO ANY
SCATTERED ACTIVITY LOOKS TO PREVAIL AS RAIN. THE EURO REMAINS MORE
ROBUST IN ITS PRECIPITATION COVERAGE DURING THIS TIME FRAME DRIVING
THE LOW POPS THROUGH MUCH OF THE AREA WITH ADDITIONAL SHOWER/STORM
ACTIVITY TO THE SOUTH OF THE STATE, BUT GENERALLY EXPECT BULK OF
ACTIVITY TONIGHT TO BE TO THE NORTH. A STRAY SHOWER HERE OR THERE,
ESPECIALLY SOUTH TO CENTRAL MAY OCCUR AT TIMES DURING THE DAYTIME
SUNDAY, BUT THE NEXT BETTER CHANCES ARE SUNDAY NIGHT INTO MONDAY
MORNING AS THE LLJ REALLY RAMPS UP AHEAD OF THE APPROACHING SURFACE
LOW WITH ADDITIONAL MOISTURE/WAA/THETA-E ADVECTION. THE BULK OF THE
RAIN/STORM ACTIVITY REMAINS TO THE WEST OF THE AREA THROUGH MUCH OF
THE EVENING, BUT NEARS/MOVES THROUGH PORTIONS OF WESTERN INTO
NORTHERN IOWA OVERNIGHT INTO MONDAY MORNING. INSTABILITY AND SHEAR
WILL BOTH BE ON THE INCREASE DURING THIS PERIOD SO WILL HAVE TO
MONITOR FOR ANY STRONG TO EVEN SEVERE STORM THAT COULD OCCUR DURING
THE OVERNIGHT TO EARLY MORNING HOURS MONDAY. STORMS WILL BE ELEVATED
SO THE MAIN THREAT, IF ANY STRONGER STORMS OCCUR IN OUR AREA, WOULD
BE HAIL. THE SPC DAY 2 MARGINAL (LEVEL 1 OUT OF 5) BARELY CLIPS OUR
FAR WESTERN COUNTY WITH THE OVERALL BETTER SEVERE WEATHER RISK TO
THE WEST OF THE AREA, THOUGH WILL CERTAINLY CONTINUE TO MONITOR.
THEN, ALL ATTENTION TURNS TO LATER IN THE DAY MONDAY INTO MONDAY
NIGHT. THE DEEPENING SURFACE LOW CROSSES TO THE NORTH WITH THE
PARENT UPPER LEVEL OPEN WAVE TROUGH CROSSING THROUGH THE CENTRAL
PLAINS AND THEN OVER THE REGION FROM MONDAY DAYTIME TO MONDAY NIGHT
RESPECTIVELY. AMPLE MOISTURE OFF THE GULF WILL LEAD TO DEW POINTS IN
THE 60S WITH THE THERMAL TROUGH EXTENDING WELL THROUGH THE AREA AND
RESULTING IN VERY WARM HIGH TEMPERATURES IN THE UPPER 70S TO 80S. A
STRONG 50+ KNOT MID-LEVEL JET CENTERED OVER NORTHEAST IA INTO MN AND
WI HELPS ENHANCE THE WIND FIELD MONDAY WITH BULK SHEAR VALUES OF 40-
60 KNOTS ACROSS THE AREA BY THE AFTERNOON. MEANWHILE, INSTABILITY
BALLOONS IN THE WARM, MOIST AIRMASS WITH SEVERAL THOUSAND J/KG
OF MLCAPE IN PLACE. ALL OF THESE THINGS TOGETHER CREATE A
FAVORABLE PARAMETER SPACE FOR SEVERE WEATHER WITH ALL MODES ON
THE TABLE. 700MB TEMPS REACHING TOWARDS +10C AROUND MIDDAY
CERTAINLY SUGGEST A CAP WILL BE IN PLACE INTO THE AFTERNOON WITH
GLOBAL MODELS STILL QUITE VARIABLE IN HOW/WHEN/WHERE ACTIVITY
KICKS OFF MONDAY. TIMING WILL REALLY MATTER FOR SEVERE MODE AND
TIMING/LOCATION STILL REMAIN IN QUESTION AT THIS TIME RANGE.
BESIDES THE WEAK CAPPING, ANY EARLY DAY ACTIVITY IN THE NORTH
COULD PROVIDE LINGERING CLOUD COVER, OR EVEN A BOUNDARY BUT
THESE SORT OF MESOSCALE DETAILS ARE HARD TO DISCERN MULTIPLE
DAYS OUT. ACTIVITY DEVELOPING IN THE WARM SECTOR COULD LEAD TO
THE DEVELOPMENT OF TORNADOES WHICH COULD BECOME STRONG, AND
LARGE HAIL, WHILE ACTIVITY ALONG THE TRAILING COLD FRONT WOULD
BE MUCH MORE LIKELY TO BE A LINE OF STORMS FEATURING STRONG WIND
GUSTS AND POTENTIALLY SOME TORNADOES. SPC HAS UPGRADED MUCH OF
CENTRAL TO NORTHERN/NORTHEAST IOWA TO A MODERATE RISK (LEVEL 4
OUT OF 5) FOR THE DAY 3 TIMEFRAME WITH AN ENHANCED RISK (LEVEL 3
OUT OF 5) THROUGH THE REST OF THE AREA. WHILE SOME UNCERTAINTY
REMAINS IN TIMING/LOCATION/THREAT, AND DETAILS MAY STILL CHANGE
IN THE NEXT FEW DAYS, NOW IS THE TIME TO REVIEW YOUR SEVERE
WEATHER PLANS AND CONSIDER MAKING ALTERNATE PLANS FOR ANY
OUTDOOR ACTIVITIES ON MONDAY.
COOLER AND DRIER CONDITIONS FOLLOW ON TUESDAY INTO WEDNESDAY BEFORE
ADDITIONAL PRECIPITATION CHANCES RETURN TO THE REGION TO END THE
WEEK.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1249 PM CDT SAT APR 26 2025
VFR CONDITIONS WITH NOTHING BEYOND INCREASING MID CLOUDS CAN BE
EXPECTED THIS EVENING. ALTHOUGH LIKELY REMAINING VFR, CEILINGS
DO LOWER SOMEWHAT AS THE POTENTIAL FOR SHOWERS INCREASES NORTH
OVERNIGHT AND INTO SATURDAY MORNING. EVENTUALLY LOW LEVEL
MOISTURE INCREASES SUFFICIENTLY THAT AT LEAST MVFR CEILINGS MAY
DEVELOP CENTRAL AND WEST BY LATE SUNDAY MORNING.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...05
AVIATION...SMALL
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