059
FXUS63 KDMX 281148
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
548 AM CST THU NOV 28 2024
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
KEY MESSAGES
- EXTENDED PERIOD OF BELOW NORMAL TEMPS INTO EARLY NEXT WEEK
- CHANCES FOR LIGHT SNOW (30-40%) SOUTH EARLY SATURDAY, WITH A
FEW OTHER MINOR WINDOWS OF POTENTIAL FLURRIES AS WELL
DISCUSSION
ISSUED AT 338 AM CST THU NOV 28 2024
OUR MUCH ADVERTISED NORTHWEST FLOW REGIME WAS IN PLACE THIS
THANKSGIVING MORNING AND WILL REMAIN LOCKED IN TO VARIED DEGREES
INTO THE MIDDLE OF NEXT WEEK KEEPING BELOW NORMAL TEMPS IN
PLACE UNTIL SOME MODERATION TOWARD THE END OF THE PERIOD. A
SECONDARY H85 COLD FRONT WAS NOTED FROM KS THROUGH IA AND INTO
THE GREAT LAKES EARLY THIS MORNING WITH EXPANSIVE STRATUS IN
ITS WAKE, WHICH SHOULD GENERALLY REMAIN IN PLACE THROUGHOUT THE
DAY. WEAK SHORT WAVES WILL ALSO CONTINUE TO SPILL INTO THE
NORTHERN PLAINS TODAY OUT OF THE CURRENT SK UPPER LOW AND LEFT
ENTRANCE REGION OF THE ASSOCIATED MT JET SEGMENT GENERATING WEAK
VERTICAL MOTION FROM NORTHERN IA AND NORTHWARD. THIS LIFT,
ALONG WITH LOW STATIC STABILITY DUE TO HIGHER 0-1KM LAPSE RATES
IN COLD ADVECTION, MAY PRODUCE A FEW FLURRIES THERE LATER TODAY,
AND ALTHOUGH NOT SPECIFICALLY MENTIONED IN THE FORECAST DUE TO
LOW PREDICTABILITY, INFREQUENTLY THROUGH AT LEAST THE WEEKEND.
WITH COOLER WINTER-LIKE TEMPS AND NO SIGNIFICANT PUSH OF DRIER
AIR ANY STRATUS OR STRATOCUMULUS IN THE 3-5K FT LAYER MAY REACH
<= -10C AND BE FAVORABLE FOR TOKEN COLUMN OR PRISM ICE CRYSTAL
PRODUCTION, NOT TO MENTION OTHER POTENTIAL AT COOLER TEMPS
FURTHER ALOFT.
THE ONLY MORE FOCUSED SYSTEM OF NOTE THROUGH THE PERIOD WILL BE
SATURDAY MORNING THROUGH THE MO VALLEY AS WEAK WAVES CONTINUE
TO RIDE THE NORTHWEST FLOW. ONE SUCH WAVE WILL INCREASE BOTH
KINEMATIC AND THERMODYNAMIC SUPPORT OVER SOUTHERN AND ESPECIALLY
SOUTHWEST IA, WITH SOME FRONTOGENETIC CONTRIBUTIONS ALONG THE
BAROCLINIC ZONE AS WELL. CONFIDENCE IS FAIRLY HIGH THAT LIGHT
SNOW WILL DEVELOP SOMEWHERE IN THE NE/KS/MO/IA REGION, BUT THE
QUESTION REMAINS NE-SW PLACEMENT OF THE PRECIPITATION. GEFS AND
EPS MEASURABLE PRECIP PROBABILITIES CONTINUE TO HIGHLIGHT THE
MOST LIKELY LOCATION JUST TO OUR SOUTH ACROSS NORTHERN MO,
HOWEVER THE SYSTEM HAS NOW ENTERED THE VALID NAM AND NAMNEST
WINDOWS AND BOTH OF THOSE NMM CORE SOLUTIONS SUGGEST A FARTHER
NE PLACEMENT, POSSIBLY JUST TO THE DES MOINES METRO. THUS HAVE
FAIRLY BROADBRUSHED 20-40% CHANCES FOR MEASURABLE PRECIP FROM
DES MOINES TOWARD THE MO BORDER WITH THE HIGHER END OF THAT
RANGE SOUTH. CONFIDENCE IN WHERE THE BAND LOCATES IS LOW TO
MEDIUM, BUT THERE IS GOOD CONSENSUS AMONG BOTH THE DETERMINISTIC
AND ENSEMBLE GUIDANCE THAT 1"+ AMOUNTS WOULD OCCUR WHERE EVER
THAT MAY BE, WITH SOUTHERN IA STILL IN PLAY.
THERE IS INSUFFICIENT SIGNAL FOR ANY PRECIP MENTION LATER IN THE
WEEKEND AND INTO THE MIDDLE OF NEXT WEEK, ALTHOUGH AS MENTIONED
OTHER PERIODS OF FLURRIES CANNOT BE RULED OUT. THE NORTHWEST
FLOW REGIME WILL REMAIN IN PLACE THROUGH THE VALID PERIOD (WED),
BUT SOME MODERATION IN TEMPERATURES IS ANTICIPATED. THE MAGNITUDE
OF THE GREAT LAKES/EASTERN CONUS MEAN TROUGH SHOULD DECREASE
NEXT WEEK WITH OUR H5 HEIGHTS BACK TO 552 DAM AND WEAK CANADIAN
SHORT WAVES INDUCING RETURN FLOW AND WARM ADVECTION AS THE
SURFACE HIGH DEPARTS TUESDAY. THIS SHOULD RETURN TEMPS BACK TO
MORE SEASONAL LEVELS, WITH HIGHS BACK ABOVE FREEZING TUE, AND
ABOVE 40F IN MANY AREAS WED.
AVIATION /12Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 548 AM CST THU NOV 28 2024
MVFR/VFR CEILINGS WERE IN PLACE ACROSS CENTRAL IA AT 12Z AND
SHOULD CONTINUE INTO MIDDAY. A GRADUAL TREND MORE TOWARD VFR
CONDITIONS IS EXPECTED DURING THE AFTERNOON AND EVENING,
ALTHOUGH MVFR STRATUS MAY LINGER NORTHEAST NEAR KMCW INTO THE
NIGHT. WINDS WILL CHANGE LITTLE THROUGH THE PERIOD, STAYING
NORTHWEST WITH GUSTS FROM 20-25 KTS NORTHEAST.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...SMALL
AVIATION...SMALL
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