236
FXUS63 KDVN 212357
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
557 PM CST TUE JAN 21 2025
..00Z AVIATION UPDATE
KEY MESSAGES
- A COLD WEATHER ADVISORY IS IN EFFECT FOR THE MAJORITY OF THE
OUTLOOK AREA (EXCEPT THE FAR SW COUNTIES) UNTIL 2 AM TONIGHT.
WIND CHILLS AS COLD AS 15 TO 25 BELOW ZERO ARE EXPECTED.
- LIGHT ACCUMULATING SNOW IS EXPECTED LATE TONIGHT THROUGH
WEDNESDAY NIGHT, WITH SOME ISOLATED ACCUMULATIONS OVER AN INCH
POSSIBLE.
- TEMPERATURES BECOME SEASONAL BY WEDNESDAY, WITH A EXTENDED
DRY STRETCH EXPECTED THROUGH THE UPCOMING WEEKEND.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 145 PM CST TUE JAN 21 2025
A VERY COLD AIR MASS REMAINS OVER EASTERN IOWA AND NORTHWEST
ILLINOIS WITH EARLY AFTERNOON TEMPERATURES ONLY A FEW DEGREES
ABOVE OR BELOW ZERO DESPITE NO SNOWPACK ACROSS THE AREA! WIND
CHILLS HAVE STEADILY "IMPROVED" SINCE THIS MORNING, NOW MAINLY
IN THE TEENS TO NEAR 20 BELOW ZERO. TEMPERATURES WILL WARM BY A
FEW MORE DEGREES THROUGH THE AFTERNOON BEFORE FALLING AGAIN
EARLY THIS EVENING WITH LOWS FORECAST IN THE SINGLE DIGITS ABOVE
AND BELOW ZERO. THE COLD TEMPERATURES COMBINED WITH INCREASING
SOUTHERLY WINDS (15-25+ MPH) WILL CREATE DANGEROUSLY COLD WIND
CHILLS INTO TONIGHT. FOR THIS REASON, A COLD WEATHER ADVISORY IS
IN EFFECT UNTIL 2 AM FOR MOST OF THE OUTLOOK AREA (EXCEPT FOR
VAN BUREN, SCOTLAND, AND CLARK CO.) FOR WIND CHILLS BETWEEN 15
TO 25 BELOW ZERO. THE COLDEST VALUES NEAR 20 BELOW OR SLIGHTLY
COLDER ARE FORECAST NORTH OF I-80.
WHILE THE WINDS WILL REMAIN GUSTY OVERNIGHT, THE SOUTHERLY FLOW
WILL LEAD TO SLOWLY RISING TEMPERATURES AND A SLIGHT
IMPROVEMENT IN THE WIND CHILLS TO A RANGE OF ZERO TO 15 BELOW,
AND FOR THIS REASON HAVE THE ADVISORY EXPIRING AT 2 AM. THERE IS
A CHANCE FOR LIGHT SNOW TO DEVELOP ACROSS THE FAR NW (NORTH OF
CEDAR RAPIDS) LATE TONIGHT AS ELEVATED WARM AIR ADVECTION
GRADUALLY SATURATES THE COLUMN IN A TOP DOWN FASHION. THIS COULD
RESULT IN A DUSTING TO HALF INCH BY EARLY WEDNESDAY MORNING.
HOWEVER, IT APPEARS THAT MOST OF THE LIGHT SNOW WITH THIS SYSTEM
WILL HOLD OFF UNTIL LATER WEDNESDAY MORNING ACROSS THE NORTH,
EVENTUALLY WORKING TO THE ESE INTO THE AFTERNOON/EVENING.
LONG TERM /WEDNESDAY THROUGH TUESDAY/
ISSUED AT 145 PM CST TUE JAN 21 2025
WEDNESDAY WILL BE A DAY OF TRANSITION TO MORE SEASONAL CONDITIONS AS
THE SOUTHERN RETURN FLOW/WARM AIR ADVECTION INCREASES FURTHER.
FARTHER WEST, AN APPROACHING MID-LEVEL SHORTWAVE IS PROGGED TO SWEEP
THROUGH THE AREA FROM WEST TO EAST, LEADING TO INCREASING CHANCES
(40 TO 70%) OF LIGHT SNOW ACROSS THE AREA. MODEL SOUNDINGS
INDICATE INCREASING SATURATION WITHIN THE DENDRITIC GROWTH ZONE
ALOFT, WHICH SHOULD EFFICIENTLY GENERATE ICE CRYSTALS. THERE
DOES APPEAR TO BE SOME DRY AIR IN THE LOWER LEVELS, SO IF THIS
DRY AIR HANGS ON LONGER THAN EXPECTED, THIS COULD LIMIT SNOW
TOTALS. AT THIS TIME, IT APPEARS THAT THE DRY AIR WILL ERODE,
LEADING TO SOME LIGHT SNOWFALL MAINLY DURING THE WEDNESDAY PM
HOURS, ALTHOUGH THERE COULD BE SOME LIGHT SNOW FALLING ACROSS
OUR NORTHERN AREAS WEDNESDAY MORNING.
LREF ENSEMBLE GUIDANCE CONTINUES TO SUGGEST VERY HIGH (70 TO
90%+) EXCEEDANCE PROBABILITIES OF MEASURABLE SNOW (0.1" OR
MORE), ALTHOUGH MOST AREAS MAY NOT SEE MUCH SNOWFALL UNTIL
WEDNESDAY EVENING INTO WEDNESDAY NIGHT. DIVING INTO THE
ENSEMBLES PER THE WSE PLUME VIEWER, MOST OF THE MEMBERS OF THE
GEFS, EPS, AND GEPS ENSEMBLES SUGGEST TOTAL SNOWFALL NEAR 1" OR
LESS, WITH SOME MEMBERS SUGGESTING TOTALS BETWEEN 1-2 INCHES
NEAR DUBUQUE AND POINTS EAST OF THERE IN NORTHWEST ILLINOIS.
THUS, CONFIDENCE REMAINS QUITE HIGH FOR AN OVERALL MINOR
SNOWFALL EVENT. WITH THE VERY COLD PAVEMENT TEMPERATURES, IT
WILL ONLY TAKE A DUSTING TO LEAD TO SLIPPERY TRAVEL CONDITIONS.
DESPITE THE SNOWFALL, TEMPERATURES SHOULD WARM INTO THE MIDDLE
20S NORTHEAST TO THE LOWER 30S SOUTHWEST, ESSENTIALLY NEAR
AVERAGE FOR THIS TIME OF THE YEAR.
FOR THURSDAY THROUGH THE UPCOMING WEEKEND, WE WILL SEE SOME
FLUCTUATIONS IN TEMPERATURES, WITH SOME COOLER THAN AVERAGE DAYS
THURSDAY AND FRIDAY BEFORE A SIGNIFICANT WARM-UP FOR SATURDAY (HIGHS
ABOVE FREEZING FOR MOST?). OVERNIGHT TEMPERATURES WILL, OF COURSE,
BE ON THE COLD SIDE, ESPECIALLY THURSDAY NIGHT/FRIDAY MORNING, WITH
LOWS IN THE SINGLE DIGITS ABOVE ZERO. WINDS SHOULD REMAIN LIGHT AND
VARIABLE THOUGH, SO FRIGID WIND CHILLS AREN'T EXPECTED TO BE WORTHY
OF A COLD WEATHER HEADLINE. ADDITIONALLY, THERE AREN'T ANY NOTABLE
SIGNS OF PRECIPITATION, EVEN WITH A FEW MID-LEVEL IMPULSES MOVING
THROUGH AT TIMES. OVERALL, NOT MUCH ELSE OF NOTE IN THE
EXTENDED.
AVIATION /00Z TAFS THROUGH 00Z THURSDAY/
ISSUED AT 550 PM CST TUE JAN 21 2025
A VFR EVENING WITH SFC WINDS CONTINUING TO BACK TO THE SOUTH AND
SOUTHWEST. THE WINDS WILL BECOME GUSTY AT 15 TO 25 KTS IN
TIGHTENING PRESSURE GRADIENT BETWEEN DEPARTING ARCTIC HIGH
PRESSURE AND A CLIPPER DIGGING INTO THE NORTHERN GRT LKS. CIGS
WILL START TO LOWER WITH THIS SYSTEM FROM THE NORTHWEST, WITH
EMBEDDED LIGHT OR SNOW SHOWERS MOVING IN ALONG AND NORTH OF THE
HWY 30 CORRIDOR LATE TONIGHT AND WED MORNING. THE SNOW AND
LOWERING CIGS WILL CONTINUE TO SPREAD SOUTH AND EAST DURING THE
AFTRERNOON, WITH BOUTS OF MVFR SNOW REDUCED VSBYS AND CIGS
IMPACTING MOST SITES EXCEPT MAYBE AT BRL THROUGH 00Z THU.
DVN WATCHES/WARNINGS/ADVISORIES
IA...COLD WEATHER ADVISORY UNTIL 2 AM CST WEDNESDAY FOR IAZ040>042-
051>054-063>068-076>078-087>089-099.
IL...COLD WEATHER ADVISORY UNTIL 2 AM CST WEDNESDAY FOR ILZ001-002-
007-009-015>018-024>026-034-035.
MO...NONE.
SHORT TERM...UTTECH
LONG TERM...SCHULTZ/UTTECH
AVIATION...12
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