049
FXUS63 KDMX 182054
AFDDMX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DES MOINES IA
254 PM CST SAT JAN 18 2025
KEY MESSAGES
- DANGEROUS COLD WITH WIND CHILLS TO -20 OR COLDER AT TIMES
TONIGHT THROUGH TUESDAY.
- WARMING BACK TOWARDS THE UPPER 20S TO LOW 30S BY THE MIDDLE
TO END OF THE WEEK.
- LIGHT SNOW POSSIBLE (20-30% CHANCE) ON WEDNESDAY INTO
THURSDAY THIS WEEK.
DISCUSSION
ISSUED AT 250 PM CST SAT JAN 18 2025
COLD AIR IS SETTLING ACROSS THE AREA TODAY. BREEZY NORTHWEST WINDS
AT 20-30 MPH TODAY CONTINUE TO PUSH COLD AIR INTO THE AREA, ALSO
KEEPING WINDS CHILLS NEAR OR BELOW ZERO IN MANY CASES. IN FACT, WITH
TEMPERATURES YESTERDAY IN THE 40S TO NEAR 50, THE DIFFERENCE IN
APPARENT TEMPERATURES FROM YESTERDAY AFTERNOON TO THIS AFTERNOON
ARE 40-50 DEGREES COLDER ACROSS THE AREA. THIS EVENING A
SECONDARY LOBE OF VORTICITY WILL ROTATE ACROSS THE AREA,
EMBEDDED WITHIN THE PARENT TROUGH. THIS WILL BRING A REINFORCING
SHOT OF COLD AIR ACROSS THE AREA, SENDING TEMPERATURES ON
SUNDAY EVENING EVEN COLDER. THE COLD WEATHER ADVISORY WILL
REMAIN IN EFFECT SUNDAY MORNING FOR WIND CHILLS OF -20 TO -30 OR
COLDER. AT THE SAME TIME, LOW STRATUS IS EXPECTED TO FILL IN
ACROSS NORTHERN IOWA. AS WAS OBSERVED LAST EVENING, LIGHT SNOW
MAY DEVELOP BENEATH THIS LAYER. SOUNDINGS CONTINUE TO SHOW DEEP
DRY AIR TO BATTLE, HOWEVER THIS STRONG SHEAR/COLD AIR ADVECTION
REGIME OFTEN PRODUCES ISOLATE SNOW SHOWERS.
COLD CONTINUES, OR ALSO BECOMES EVEN COLDER, INTO MONDAY AND
TUESDAY. AT THE SAME TIME, WINDS DO BEGIN TO EASE. THIS WILL RESULT
IN CONTINUED PERIODS OF WIND CHILLS AROUND -20 TO -25 THROUGH
TUESDAY. SOUTHERLY FLOW RETURNS LATER TUESDAY WHICH WILL START
A RELATIVE WARMING TREND INTO THE END OF THE WEEK. A SHORTWAVE
WILL PASS ACROSS THE AREA ON WEDNESDAY INTO THURSDAY WHICH WILL
BRING A CHANCE (20-30%) FOR LIGHT SNOW ACROSS THE AREA -
ESPECIALLY NORTH. NBM REMAINS DRY WITH THE PASSAGE, HOWEVER WITH
SYNOPTIC MODELS TRENDING TOWARDS PRECIPITATION SEVERAL RUNS IN
A ROW, HAVE ADDED THIS TO THE FORECAST. AMOUNTS LOOK MINOR AT
THIS TIME, BUT WILL CONTINUE TO MONITOR FOR TRENDS. OTHERWISE,
DESPITE CONSISTENCY IN WARMING BACK TO THE 30S BY THE END OF THE
WEEK, MODELS DIVERGE WITH REGARDS TO THE LARGER PATTERN AND
PRECIPITATION TRENDS INTO THE WEEKEND.
AVIATION /18Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 1125 AM CST SAT JAN 18 2025
BREEZY WIND OUT OF THE NORTHWEST WILL GUST 20-25+ KTS THROUGH
THE TAF PERIOD, IN MOST CASES NOT DIMINISHING OVERNIGHT. AS
OCCURRED LAST EVENING, LOW STRATUS IS EXPECTED ACROSS NORTHERN
IOWA OVERNIGHT (INCLUDED AT KMCW/KALO AT THIS TIME). VERY
ISOLATED SNOW SHOWERS MAY DEVELOP BENEATH THE STRATUS IN THIS
BREEZY NORTHWEST FLOW SETUP OVERNIGHT. THESE SHOWERS ARE OFTEN
HIGHLY ISOLATED AND SHORT LIVED, THUS HAVE NOT INCLUDED IN TAFS
AT THIS TIME. SHOULD THEY OCCUR, A PERIOD OF MVFR VISIBILITY TO
ACCOMPANY THE LOWER CEILINGS WOULD BE THE MOST LIKELY SCENARIO.
DMX WATCHES/WARNINGS/ADVISORIES
COLD WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR
IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-
081>086-092>097.
DISCUSSION...HAGENHOFF
AVIATION...HAGENHOFF
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