841
FXUS63 KDVN 172058
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
258 PM CST FRI JAN 17 2025
KEY MESSAGES
- COLDEST AIR OF THE SEASON SO FAR EXPECTED THIS WEEKEND THROUGH
EARLY NEXT WEEK.
- A COLD WEATHER ADVISORY HAS BEEN ISSUED FOR PARTS OF EASTERN
IOWA LATE SATURDAY NIGHT THROUGH SUNDAY MORNING. THIS IS THE
FIRST IN THIS DEVELOPING COLD SPELL, WHICH IS LIKELY TO
FEATURE ADDITIONAL COLD WEATHER HEADLINES AS THE COLD AIR
PEAKS SUNDAY INTO MONDAY.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 251 PM CST FRI JAN 17 2025
FULL SUNSHINE AND DRY GROUND FOSTERING DEEP MIXING AND OWING TO
GUSTY SOUTHWEST WINDS TO 30-35+ MPH. THIS AND POTENTIALLY SOME
ASSISTANCE OF PRE-FRONTAL COMPRESSIONAL HEATING AHEAD OF AN
APPROACHING COLD FRONT, HAS PROPELLED TEMPS WELL ABOVE NORMAL AND
INTO THE UPPER 40S TO MID 50S THIS AFTERNOON. THE COLD FRONT IS
CURRENTLY MAKING INROADS AND WILL SWEEP ACROSS THE ENTIRE AREA
THROUGH MID EVENING. THE BRUNT OF THE COLD AIR HOWEVER, LAGS BEHIND
THE FRONT AND DOES NOT ARRIVE UNTIL LATE EVENING THROUGH THE
OVERNIGHT. AS IT DOES WE'LL SEE TEMPS PLUNGE AND WINDS TURN GUSTY
FROM THE NORTHWEST UP TO 30 TO 40 MPH. CAN'T TOTALLY RULE OUT
ADVISORY CRITERIA BRIEFLY BEING MET, BUT OVERALL WINDS AT 35-40 KT
ATOP THE MIXED LAYER AND LACK OF A VERY STRONG ISALLOBARIC PUSH
ALBEIT STILL MODEST WILL LIKELY KEEP ANY THREAT FAIRLY ISOLATED.
WILL CONTINUE WITH SOME LOW CHANCES FOR RAIN THIS EVENING FAR
SOUTH/EAST, BEING ON THE NORTH SIDE OF THE PHASING ENERGY OVER
THE MID/LOWER MISSISSIPPI VALLEY, BUT OVERALL MAINLY DRY. LATE
THIS EVENING/OVERNIGHT THERE MAY BE A FEW FLURRIES WITH A SHALLOW
MOISTURE LAYER ATOP STEEPENING NEAR SURFACE LAPSE RATES. THE NAM
SOUNDINGS ARE MORE MOIST AND WOULD INDICATE SOME POTENTIAL FOR EVEN
FREEZING DRIZZLE WITH LOSS OF IN-CLOUD ICE, BUT THE MODEL HAS BEEN
VERIFYING TOO MOIST AND THEREFORE HAVE NO MENTION AND JUST KEPT
WITH FLURRIES POTENTIALLY FOR A FEW HOUR PERIOD WITH THE ONSET OF
THE STRONG COLD ADVECTION LATE EVENING INTO OVERNIGHT.
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 251 PM CST FRI JAN 17 2025
THE FORECAST REMAINS UNCHANGED OVER THE WEEKEND THROUGH EARLY NEXT
WEEK, WITH BITTERLY COLD AIR SETTLING INTO THE REGION. THIS
WILL COME IN WAVES, WITH THE FIRST SURGE SATURDAY NIGHT INTO
SUNDAY. THIS WILL RESULT IN SINGLE DIGITS ABOVE/BELOW ZERO FOR
LOWS WITH WIND CHILLS IN THE NEGATIVE TEENS AND 20S AS A
LINGERING PRESSURE GRADIENT KEEPS WINDS UP AT 10-20+ MPH.
CONFIDENCE IS HIGHEST ON REACHING COLD WEATHER ADVISORY CRITERIA
OF -20F NORTH OF I-80 ON THE IOWA SIDE WHERE THE GRADIENT WILL
BE A LITTLE MORE STOUT, AND AS A RESULT WE'VE ISSUED THE
ADVISORY FOR THOSE AREAS LATE SATURDAY NIGHT THROUGH SUNDAY
MORNING. THE MAIN CORE OF THE ARCTIC AIR ARRIVES SUNDAY NIGHT
THROUGH MONDAY NIGHT ON THE BACKSIDE OF LOW PRESSURE NEAR HUDSON
BAY. THIS WILL DISLODGE A CHUNK OF ARCTIC AIR WITH 850 HPA
TEMPERATURES PROGGED AS COLD AS -25 TO -30C OVER THE REGION. IF
THESE VALUES VERIFY, THEY WILL FALL IN THE TOP 10 COLDEST 850 MB
TEMPS IN THE SPC SOUNDING CLIMATOLOGY FOR DVN (PERIOD OF RECORD
GOES BACK TO 1995). DESPITE THE LACK OF SNOW COVER AND EVEN
WITH SOME MODERATION IT'S STILL GOING TO BE BITTERLY
COLD/FRIGID. LOWS SUNDAY NIGHT THROUGH MONDAY NIGHT WILL BE IN
THE SINGLE DIGITS AND TEENS BELOW ZERO, WITH MINIMUM WIND CHILLS
OF -15 TO -30 DEGREES. THIS WILL NECESSITATE ADDITIONAL COLD
WEATHER HEADLINES.
THE FORECAST REMAINS DRY THROUGH EARLY WEEK, BUT CAN'T RULE OUT SOME
WAVES EMBEDDED IN THE N/NW FLOW. GIVEN THE LOW AMPLITUDE NATURE OF
THESE, THEY ARE HARD TO RESOLVE IN THE MODELS AT THIS JUNCTURE, AND
AS SUCH THE NBM OFFERS NO MEASURABLE POPS. BUT, SOMETHING TO KEEP AN
EYE ON AS THE ARCTIC AIR WILL BE VERY EFFICIENT AT PRODUCING SOME
FLAKAGE.
MID-LATE WEEK, WE'RE STILL ON TRACK TO SEE A PATTERN CHANGE
TOWARD MORE SEMI-ZONAL FLOW ALOFT. THIS WILL LEAD TO A MODERATION ON
TEMPERATURES, AND CAN'T RULE OUT SOME ADDITIONAL PRECIPITATION
CHANCES WITH ANY EMBEDDED WAVES BUT NOT A STRONG SIGNAL AT THIS
TIME.
AVIATION /18Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 1055 AM CST FRI JAN 17 2025
WINDS ARE THE MAIN CONCERN FOR AVIATION DURING THE PERIOD.
INITIALLY INTO THIS AFTERNOON WILL SEE GUSTY SW WINDS 15-30 KT,
WITH SOME PERIODIC LOCALLY HIGHER GUSTS 35-40 KT POSSIBLE AT
THE RIVER SITES. A COLD FRONT WILL MOVE ACROSS THE TERMINALS
21Z-03Z WITH WINDS DIMINISHING AND VEERING TO WESTERLY AS THE
FRONT APPROACHES, THEN TURNING NORTHWEST AND RAMPING UP POST-
FRONTAL, ESPECIALLY AFTER A FEW HOURS OF THE FRONTAL PASSAGE
WHEN THE COLD ADVECTION STRENGTHENS. THIS WILL FOSTER NORTHWEST
WINDS BECOMING SUSTAINED AT 15-25+ KT WITH GUSTS 25-35+ KT,
DIMINISHING SOME LATE TONIGHT INTO SAT AM BUT STAYING GUSTY.
THERE IS A CHANCE FOR MVFR CEILINGS POST-FRONTAL, BUT CONFIDENCE
ON DURATION AND TIMING IS LOW (POTENTIALLY CLOUD STREETS /
NARROW BANDS OF HORIZONTAL CONVECTIVE ROLLS) TO PRECLUDE MENTION
AT THIS TIME.
DVN WATCHES/WARNINGS/ADVISORIES
IA...COLD WEATHER ADVISORY FROM 3 AM TO NOON CST SUNDAY FOR
IAZ040>042-051>054-063>066.
IL...NONE.
MO...NONE.
SHORT TERM...MCCLURE
LONG TERM...MCCLURE/SCHULTZ
AVIATION...MCCLURE
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