057
FXUS63 KDMX 200849
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
249 AM CST MON JAN 20 2025
KEY MESSAGES
- ARCTIC COLD SNAP CONTINUES. HIGH CONFIDENCE OF DANGEROUSLY
COLD WIND CHILLS OF -20F TO -35F TONIGHT INTO TUESDAY
MORNING.
- TEMPERATURES MODERATE MID-WEEK ALONG WITH CHANCES (20-30%) FOR
LIGHT SNOW WEDNESDAY AND AGAIN LATE THURSDAY. ACCUMULATIONS
WILL BE AN INCH OR LESS, BUT LOCALIZED MINOR TRAVEL IMPACTS
CANNOT BE RULED OUT.
DISCUSSION
ISSUED AT 243 AM CST MON JAN 20 2025
A DEEP, BROAD UPPER TROUGH NOW BLANKETS MUCH OF THE CONUS WITH A 498
DAM 500MB LOW CAMPING OUT BETWEEN THE GREAT LAKES AND HUDSON
BAY. AT THE SURFACE A 1040+MB SURFACE HIGH REMAINS ANCHORED OVER
THE NORTHERN PLAINS WITH A RIDGE AXIS STRETCHING SOUTH AND
EAST. NORTHERLY WINDS TO THE EAST OF THE DEEP SFC HIGH WILL
CONTINUE TO FUNNEL ARCTIC AIR INTO THE REGION TODAY AS TEMPS
STRUGGLE AGAIN AND BITTER CONDITIONS DOMINATE. TEMP ADVECTION
IS NEARLY NEUTRAL AT THE MOMENT, BUT COLD AIR ADVECTION TAKES
OVER AGAIN BY LATE MORNING INTO THE AFTERNOON AS ANOTHER
SHORTWAVE TROUGH ROUNDS THE PARENT UPPER LOW. LOW LEVEL CLOUD
COVER WILL INCREASE ALONG WITH THE POTENTIAL FOR MORE HCRS AND
SCATTERED FLURRIES AS THE TOP OF THE MIXED LAYER CROSSES THE
FROST POINT. THE COLD SNAP PEAKS TONIGHT AND WINDS RELAX A BIT
AS THE SFC HIGH DISLODGES EASTWARD. TEMPS RAPIDLY FALL AS CLOUD
COVER DISSIPATES AND CONDITIONS BECOME MORE FAVORABLE FOR
EFFICIENT RADIATIONAL COOLING. STATISTICAL GUIDANCE CONTINUES
TO BE MORE AGGRESSIVE THAN NBM OUTPUT AND ADVERTISES LOWS AS
COLD AS -20 OR COLDER OVER NORTHERN IOWA. STUCK WITH NBM FOR NOW
DUE TO UNCERTAINTIES WITH 5-10 MPH WIND BEING JUST ENOUGH TO
KEEP THE BOTTOM FROM COMPLETELY FALLING OUT ON TEMPS. THE
LIGHTER WINDS COMBINED WITH THE BITTER COLD TEMPS STILL PUSH
WIND CHILLS INTO DANGEROUS TERRITORY WITH -20F TO -35F WIND
CHILLS LIKELY.
WARM AIR ADVECTION RAMPS UP TUESDAY BENEATH BUILDING HEIGHTS ALOFT
AND WILL FINALLY BEGIN TO PULL US OUT OF THE COLD SNAP AS THE ARCTIC
AIRMASS IS SHUNTED EAST. TEMPS STEADILY RISE THROUGH SINGLE DIGITS
AND TEENS DURING THE DAY AND HOLD STEADY OR FURTHER WARM A BIT
MORE INTO TUESDAY NIGHT. HIGHS SHOULD THEN GENERALLY BE RIGHT
AROUND SEASONAL NORMS WEDNESDAY THROUGH THE REMAINDER OF THE
WEEK. MEAN NORTHWESTERLY FLOW ALOFT REMAINS ACTIVE AS A FEW
SHORTWAVES TRACK THROUGH THE REGION AND DELIVER OPPORTUNITIES
FOR LIGHT PRECIPITATION. THE FIRST WINDOW IS TUESDAY NIGHT INTO
WEDNESDAY AS THERMAL FORCING ACTIVATES A MID-LEVEL FGEN BAND
SLIDING NW TO SE THROUGH THE STATE. GEFS AND ECENS STILL SHOW
30-60% CHANCE FOR MEASURABLE PRECIP WITH THE HIGHEST CHANCES
NORTH, AND HAVE ALSO BEGUN TO SHOW LOW PROBS (10-20%) FOR UP TO
1" OF SNOW ACCUMULATION. HEDGING A BIT TOWARD THE DRIER SIDE OF
GUIDANCE GIVEN THAT MOISTURE WILL LIKELY BE A SCARCE COMMODITY
IN THE IMMEDIATE WAKE OF THE EXTREMELY DRY ARCTIC AIRMASS.
ANOTHER WAVE DROPS THROUGH LATE THURSDAY AND MAY BRING ANOTHER
ROUND OF LIGHT SNOW AND/OR FLURRIES, MAINLY WEST. MODELS START
TO DIVERGE MORE NOTABLY TOWARD THE WEEKEND AS THE UPPER FLOW
FLATTENS OUT. SPURIOUS LOW AMPLITUDE WAVES COULD DELIVER
ANOTHER OPPORTUNITY FOR LIGHT PRECIPITATION, BUT CONFIDENCE IN
TIMING AND LOCATION OF THESE DISTURBANCES IS NOT HIGH ENOUGH TO
DEVIATE AWAY FROM THE DRY NBM AT THIS POINT.
AVIATION /06Z TAFS THROUGH 06Z TUESDAY/
ISSUED AT 1020 PM CST SUN JAN 19 2025
NO MAJOR CHANGES FROM PREVIOUS PACKAGE. VFR CONDITIONS REMAIN
AT THE MOMENT, BUT ANOTHER ROUND OF LOWERING CIGS WILL ARRIVE
BETWEEN 10 AND 12Z NORTH SITES, WITH EVENTUAL MVFR CONDITIONS
AFFECTING MCW/ALO AND POSSIBLY FOD FOR 3 TO 4 HOURS EACH SITE.
WITH THE PASSAGE OF ANOTHER FRONT/WAVE, BRIEF PERIOD OF LIGHT
FLURRIES OR SNOW SHOWERS POSSIBLE AFT 18Z. COVERAGE/IMPACTS
REMAIN LOW AND HAVE LEFT OUT OF TERMINALS. NORTHWEST WINDS AGAIN
INCREASE 12 TO 15KT GUSTING TO 20/22KT MOST SITES THROUGH 00Z;
RELAXING SLIGHTLY AFT 00Z. /REV
DMX WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY UNTIL 11 AM CST THIS MORNING FOR
IAZ004>007-015>017-023>028-033>039-044>050-057>059-070-071.
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO MIDNIGHT CST
TONIGHT FOR IAZ004>007-015>017-023>028-033>039-044>050.
EXTREME COLD WARNING FROM MIDNIGHT TONIGHT TO 9 AM CST TUESDAY
FOR IAZ004>007-015>017-023>028-033>039-044>050.
COLD WEATHER ADVISORY FROM 6 PM THIS EVENING TO 9 AM CST
TUESDAY FOR IAZ057>062-070>075-081>086-092>097.
DISCUSSION...MARTIN
AVIATION...REV
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page