195
FXUS63 KDMX 291143
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
543 AM CST FRI NOV 29 2024
...UPDATED FOR THE 12Z AVIATION DISCUSSION...
KEY MESSAGES
- CONTINUED BELOW NORMAL TEMPERATURES THROUGH EARLY NEXT WEEK
BEFORE RETURNING TO MORE SEASONAL VALUES BY THE MIDDLE OF NEXT
WEEK
- SLIGHT CHANCE FOR MEASURABLE LIGHT SNOW SOUTH EARLY SAT
(~20%), BUT BETTER POTENTIAL HAS TRENDED SOUTHWARD
- FLURRIES POSSIBLE WEST LATE SATURDAY
DISCUSSION
ISSUED AT 329 AM CST FRI NOV 29 2024
IOWA WILL REMAIN LOCKED INTO PERSISTENT NORTHWEST FLOW ALOFT OF
VARIED DEGREES THROUGH AT LEAST THE MIDDLE OF NEXT WEEK KEEPING
OUR MAIN FORECAST THEMES BELOW NORMAL TO NORMAL TEMPERATURES,
AND BELOW NORMAL PRECIPITATION. AFTER SOME FLURRIES YESTERDAY,
WE'LL START OUT WITH A BREAK FROM PRECIPITATION WITH DRIER,
SUBSIDENCE IN PLACE AS A SPEED MAX AND NOTED PV ANOMALY ROTATES
THROUGH THE GREAT LAKES IN THE BASE OF THE ONTARIO LONG WAVE
TROUGH. LINGERING STRATUS NORTHEAST SHOULD DEPART, LEADING TO
SOME SUNSHINE FOR THE MORNING BEFORE CLOUDS INCREASE YET AGAIN
SOUTHWEST AS WEAK WAVES EJECT OUT OF BC/WA.
WEAK TO MODERATE KINEMATIC AND THERMODYNAMIC FORCING WILL
INCREASE LATER TODAY INTO THE PLAINS AND MO VALLEY, AND THERE
COULD BE SOME LIGHT PRECIP ALOFT SOUTHWEST BY AFTERNOON, BUT
PLENTY OF DRY AIR BELOW 2KM SHOULD PRECLUDE ANYTHING REACHING
THE GROUND. LOW LEVEL HUMIDITIES MAY INCREASE SUFFICIENTLY FOR
SOME FLURRIES SOUTHWEST BY EVENING, WITH OUR ATTENTION TURNING
TO THE SYSTEM WE'VE BEEN WATCHING FOR SEVERAL DAYS. NEARLY ALL
OF THE DETERMINISTIC AND ENSEMBLE GUIDANCE SOLUTIONS NOW SUGGEST
MUCH, IF NOT ALL, OF THE SNOW JUST TO OUR SOUTH WITH FORCING
INCREASING ACROSS NORTHERN MO EARLY SATURDAY MORNING. CONCERNS
ABOUT PREVIOUS NAM/NAMNEST SOLUTIONS FARTHER NORTH INTO IA HAVE
ABATED WITH THOSE MODELS NOW INTO MO WITH CONSENSUS. HAVE
TRENDED POPS DOWN, BUT STILL KEPT SOME SLIGHT CHANCES (~20%) OF
MEASURABLE LIGHT SNOW FAR SOUTH FOR SOME TEMPORAL CONTINUITY.
RIGHT ON ITS HEELS, LIFT WILL INCREASE ONCE AGAIN INTO THE MO
VALLEY AS THE CURRENT SK COMPACT PV ANOMALY DROPS INTO THE
NORTHERN PLAINS SATURDAY AND INTERACTS WITH ADDITIONAL WEAK
SUPPORT EMBEDDED IN THE NORTHWEST FLOW. MID LEVEL KINEMATIC
FORCING REMAINS FAIRLY STEADY ALONG AND AHEAD OF THIS FEATURE
THROUGH SATURDAY EVENING, HOWEVER UPSTREAM THERMODYNAMIC AND
FRONTOGENETIC SUPPORT WEAKENS AS IT CROSSES THE MO RIVER. THIS
WILL HAVE TO BE MONITORED IN THE NEXT FEW MODEL RUNS, BUT
CURRENT EXPECTATIONS ARE FOR ANY MEASURABLE SNOW POTENTIAL TO
REMAIN UPSTREAM LEAVING ONLY FLURRIES MENTIONED WEST DURING THE
EVENING.
ALTHOUGH THERE COULD BE SOME NONDESCRIPT POTENTIAL FOR FLURRIES
LATER IN THE WEEKEND OR EARLY NEXT WEEK, THE REMAINDER OF THE
FORECAST IS DRY FOR THE TIME BEING. ONE LAST SHORT WAVE SHOULD
DROP THROUGH THE UPPER MS VALLEY OR GREAT LAKES LATE MONDAY
FOLLOWED BY A COLD ~1035 MB SURFACE PRESSURE RIDGE INTO THE
STATE MONDAY NIGHT, WHICH WILL HAVE TO BE WATCHED FOR NOTED
RADIATIONAL COOLING DEPENDING ON CLOUD TRENDS. AFTER THIS, A
STRONG CANADIAN WAVE AND SURFACE LOW WILL INDUCE WARM ADVECTION
THROUGH THE MO AND MS VALLEYS. SOME TRACE PRECIP AMOUNTS ARE
POSSIBLE IN THE WARM ADVECTION REGIME NORTH, BUT OUR MAIN
SENSIBLE WEATHER REFLECTION WILL BE AN END TO THIS COLD EPISODE
AND TEMPERATURES RETURNING TO MORE SEASONAL VALUES BY THE
MIDDLE OF NEXT WEEK.
AVIATION /12Z TAFS THROUGH 12Z SATURDAY/
ISSUED AT 543 AM CST FRI NOV 29 2024
AREAS OF MVFR STRATUS OVER EASTERN SECTIONS WILL LINGER FOR A
FEW MORE HOURS BUT SHOULD EXIT TO THE EAST BY 15Z FOLLOWED BY
SEVERAL HOURS OF CLEAR SKIES. CONFIDENCE IN VFR CONDITIONS FOR
THE REMAINDER OF THE PERIOD IS HIGH, WITH CLEAR SKIES CONTINUING
SOUTH AND MID CLOUDS INCREASING SOUTH DURING THE AFTERNOON AND
PERSISTING INTO THE NIGHT. NW WINDS WILL REMAIN GUSTY AT +/- 25
KTS THROUGH THE DAYLIGHT HOURS BEFORE DIMINISHING INTO SUNSET.
DMX WATCHES/WARNINGS/ADVISORIES
NONE.
DISCUSSION...SMALL
AVIATION...SMALL
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