454
FXUS63 KDMX 190848
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
248 AM CST SUN JAN 19 2025
KEY MESSAGES
- DANGEROUSLY COLD CONDITIONS THROUGH TUESDAY MORNING WITH WIND CHILLS
OF -20F TO -30F AT TIMES, ESPECIALLY OVER THE NORTHERN HALF
OF THE STATE.
- TEMPERATURES WARM BACK TO CLOSER TO SEASONAL NORMS WEDNESDAY
INTO THURSDAY ALONG WITH CHANCES (AROUND 20%) FOR LIGHT
SNOWFALL.
DISCUSSION
ISSUED AT 242 AM CST SUN JAN 19 2025
OUR ARCTIC COLD SNAP IS WELL UNDERWAY AS A 1040+MB SFC HIGH
ANCHORED OVER THE NORTHERN HIGH PLAINS AND BENEATH AN EXPANSIVE
DEEP TROUGH ALOFT CONTINUES TO PUSH BITTER COLD AIR INTO THE
REGION. WIND CHILLS TONIGHT HAVE FALLEN TO -10F TO -30F OVER
THE FORECAST AREA. ONLY MARGINAL RECOVERY THROUGH THE DAYLIGHT
HOURS TODAY WITH HIGHS IN THE SINGLE DIGITS ABOVE ZERO AND
STEADY NORTHWEST WINDS KEEPING WIND CHILLS COMFORTABLY BELOW
ZERO. ISSUED THE NEXT IN OUR SERIES OF COLD WEATHER ADVISORIES
FOR TONIGHT INTO MON AM FOR THE NORTHERN 2/3 OF THE FORECAST
AREA WHERE WIND CHILLS OF -20F OR COLDER ARE HIGHLY LIKELY ONCE
AGAIN. AIR TEMPS BOTTOM OUT MONDAY NIGHT AS THE SURFACE HIGH
NUDGES EASTWARD AND WINDS RELAX A BIT, ALLOWING FOR MORE
EFFICIENT RADIATIONAL COOLING WITHIN A BITTER COLD AIRMASS
CHARACTERIZED BY HIGHLY ANOMALOUS 850MB TEMPS OF -26C TO -32C.
STATISTICAL GUIDANCE FROM THE GFS AND NAM SUGGEST LOWS AS COLD
AS -20F ARE POSSIBLE IN PORTIONS OF NORTHERN IOWA. NBM AND
GEFS/ECENS ARE NOT QUITE AS AGGRESSIVE WITH <10% PROBS OF LOWS
REACHING -20F, BUT HAVE STILL BEEN STEADILY TRENDING SLIGHTLY
COLDER. ANOTHER ROUND OF COLD WEATHER HEADLINES WILL NEED TO BE
CONSIDERED WITH FUTURE FORECAST UPDATES.
MODELS HAVE BEEN TRENDING A BIT SLOWER TO ERODE THE COLD AIRMASS
TUE WITH ANOTHER DAY STUCK IN THE SINGLE DIGITS AND TEENS. A
RETURN TO SOUTHERLY SFC FLOW AND WAA TAKE OVER TUE NIGHT INTO
WED AND QUICKLY BRINGS TEMPS BACK CLOSER TO SEASONAL NORMS.
ATTENTION AT THIS POINT TURNS TO INCREASING POTENTIAL FOR LIGHT
WINTRY PRECIPITATION WED INTO THU AS SUCCESSIVE WEAK SHORTWAVES
TRAVERSE THROUGH THE PERSISTENT MEAN NORTHWEST FLOW ALOFT.
CONFIDENCE IN THE PRECIP SCENARIO IS HINDERED BY SKEPTICISM ON
THE QUALITY AND TIMING OF MOISTURE RETURN BACK INTO THE REGION
IN THE WAKE OF THE EXCEPTIONALLY DRY ARCTIC AIRMASS. BOTH THE
GEFS AND ECENS HAVE INCREASING PROBS (40-60%) FOR MEASURABLE
PRECIP, BUT VERY LOW PROBS (<10%) FOR SNOW ACCUMS EXCEEDING 1".
MAY BE LOOKING AT A HIGH POP/LOW QPF SCENARIO OF LIGHT SNOW
AND/OR FLURRIES WHICH IS TYPICALLY POORLY CAPTURED BY THE GLOBAL
MODELS AND NBM OUTPUT AT THIS TIME RANGE.
AVIATION /06Z TAFS THROUGH 06Z MONDAY/
ISSUED AT 1015 PM CST SAT JAN 18 2025
NOT MUCH CHANGE FROM PREVIOUS FORECAST. STILL SOME PATCHY MVFR
CIGS UPSTREAM, THOUGH EARLIER SNOW SHOWERS OVER MN HAVE
DIMINISHED. WILL KEEP A FEW HOURS OF POTENTIAL MVFR CIGS AT
MCW/FOD BETWEEN 08 AND 13Z. OTHERWISE MAIN CONCERN WILL BE
CONTINUED WIND GUSTS BETWEEN 18 AND 24KTS WITH HIGHER GUSTS AT
MCW AND ALO. TOWARD 21 TO 23Z, MOST SITES SHOULD RETURN TO FEW
TO SCT HIGH CLOUDS WITH VFR CONDITIONS. /REV
DMX WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY UNTIL NOON CST TODAY FOR IAZ004>007-
015>017-023>028-033>039-044>050-057>062-070>075-081>086-
092>097.
DISCUSSION...MARTIN
AVIATION...REV
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