657
FXUS63 KDVN 252017
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
217 PM CST SAT JAN 25 2020
SYNOPSIS
ISSUED AT 212 PM CST SAT JAN 25 2020
SURFACE LOW AND AN ATTENDANT 500 MB LOW WERE CENTERED ACROSS THE
GREAT LAKES EARLY THIS AFTERNOON, AND WERE KEEPING THE MIDWEST
LOCKED UNDERNEATH CLOUDY SKIES AND COOL TEMPERATURES. SNOW SHOWERS
WERE ALSO WRAPPING AROUND THE LOW, WITH THE BULK FALLING FROM
EASTERN WISCONSIN TO NORTHEAST ILLINOIS WHERE AMOUNTS UP TO 4 INCHES
WERE RECORDED.
IN OUR NECK OF THE WOODS, ONLY A FEW LIGHT SNOW SHOWERS OR FLURRIES
REMAINED WITH AFTERNOON TEMPERATURES HOLDING STEADY IN THE LOW TO
MID 30S. A FEW BREAKS IN THE CLOUDS WERE NOTED ON LATEST GOES-16
SATELLITE IMAGERY, WHICH WAS AHEAD OF SURFACE HIGH PRESSURE
LOCATED OVER EASTERN KANSAS AND WESTERN MISSOURI. THIS HIGH
PRESSURE WILL BE THE PRIMARY INFLUENCER OF OUR WEATHER FOR THE
SHORT TERM PERIOD.
SHORT TERM
(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 212 PM CST SAT JAN 25 2020
1) LEFTOVER FLURRIES AND SNOW SHOWERS WILL EXIT THE AREA TONIGHT.
2) MAINLY QUIET, DRY CONDITIONS EXPECTED TO CLOSE OUT THE WEEKEND.
3) SLIGHT CHANCE OF FLURRIES OVER EASTERN IOWA SUNDAY MORNING AND
AFTERNOON.
DISCUSSION:
THE AFOREMENTIONED SURFACE LOW PRESSURE IS PROGGED TO REACH SOUTHERN
ONTARIO AND QUEBEC EARLY SUNDAY MORNING, TAKING THE BULK OF MOISTURE
AND POCKETS OF WRAP-AROUND LIFT WITH IT. AS A RESULT, OUR CHANCES OF
SEEING ANY FLURRIES OR SNOW SHOWERS WILL DECREASE HEADING INTO
TONIGHT.
BEHIND THE LOW, WEAK SURFACE HIGH PRESSURE AND MID-LEVEL RIDGING
WILL BUILD ACROSS THE AREA TO CLOSE OUT THE WEEKEND. INCREASING
SUBSIDENCE WITH THE RIDGING WILL HELP STRENGTHEN THE INVERSION ALOFT
NOTED AROUND 800 HPA ON THE DVN 12Z SOUNDING, HELPING TO PREVENT
MUCH MIXING OUT OF THE HIGH LOW-LEVEL HUMIDITIES. AS A RESULT, NOT
EXPECTING TO SEE PLENTIFUL SUNSHINE AS WE HEAD INTO THE NEW WORK
WEEK.
FOR SUNDAY MORNING AND AFTERNOON, GUIDANCE IS IN GOOD AGREEMENT OF A
WEAK MID-LEVEL SHORTWAVE AND VORT MAX PASSING OVERHEAD. ATTENDANT
LOW-LEVEL THETA-E ADVECTION COULD PROVIDE ENOUGH LIFT TO SUPPORT
SOME SCATTERED FLURRIES ACROSS THE AREA DURING THIS PERIOD. HOWEVER,
THE LIFT WILL BE WEAKENING WITH EASTWARD PROGRESSION OF THE
SHORTWAVE, SO NOT EXPECTING FLURRIES TO BE LONG LASTING OR LEAD TO
ANY IMPACTS.
TEMPERATURES WILL BE REFLECTIVE OF THE CLOUDS OVERHEAD, BUT WILL
ALSO BE IMPACTED BY CAA INITIALLY AND THE SNOW COVER. EXPECTING LOWS
IN THE LOW TO MID 20S TONIGHT AND SUNDAY NIGHT, WITH AFTERNOON HIGHS
SUNDAY IN THE UPPER 20S TO LOW 30S.
LONG TERM
(MONDAY THROUGH SATURDAY)
ISSUED AT 212 PM CST SAT JAN 25 2020
KEY MESSAGES:
1. QUIET WEATHER PERIOD EXPECTED THROUGH MOST OF THE LONG TERM WITH
AVERAGE TO ABOVE AVERAGE TEMPERATURES.
2. A FEW WAVES ARE EXPECTED TO MOVE ACROSS THE AREA AND MAY CAUSE
LIGHT PRECIPITATION, NONE OF THEM LOOK TO BE SIGNIFICANT
DISCUSSION:
OVERALL NORTHWEST FLOW WITH A FEW CLIPPER LIKE SYSTEMS ARE EXPECTED
THROUGH THE PERIOD. INTO NEXT WEEKEND THERE ARE SUGGESTIONS A RIDGE
BUILDS IN ACROSS THE CENTRAL CONUS WITH MUCH ABOVE AVERAGE TEMPS.
CURRENT BLENDED GUIDANCE HAS HIGHS IN THE UPPER 30S TO 40S. AS WE
GET CLOSER TO NEXT WEEKEND, WE SHOULD HAVE A BETTER IDEA OF WHAT
TEMPS MAY BE. IN THE MEAN TIME, THE FIRST WAVE LOOKS TO BE IN THE
AREA TUESDAY NIGHT INTO WEDNESDAY. THE SECOND WAVE LOOKS TO AFFECT
THE AREA LATE IN THE WEEK.
THESE TWO WAVES CURRENTLY PRODUCE LITTLE QPF IN THE DETERMINISTIC
MODELS. FOR THE FIRST WAVE, THE GEFS SPREAD IS QUITE LARGE
SUGGESTING THAT THERE MAY BE A DECENT CHANCE FOR SOME LIGHT SNOW OR
FREEZING DRIZZLE INTO WEDNESDAY MORNING. IF IT IS SNOW IT SHOULD BE
LIGHT, IF IT IS FREEZING DRIZZLE AS SOME OF THE SOUNDINGS SUGGEST
THEN WE MAY SEE GREATER IMPACTS. CURRENTLY FAVOR SNOW AS CONFIDENCE
IN ZL IS LOW. THE SECOND WAVE FOR THE END OF THE WEEK HAS JUST
SLIGHTLY HIGHER QPF THAN THE FIRST WAVE. THERE ARE TIMING
DIFFERENCES BETWEEN ALL OF THE GUIDANCE SO CONFIDENCE EXACT TIMING
IS LOW, HOWEVER THE QPF TAKEN TOGETHER SUGGESTS A TENTH OF QPF
APPEARS LIKELY AT THIS TIME.
AVIATION
(FOR THE 18Z TAFS THROUGH 18Z SUNDAY AFTERNOON)
ISSUED AT 1108 AM CST SAT JAN 25 2020
PLENTIFUL LOW-LEVEL MOISTURE IN PLACE ACROSS THE AREA WILL HELP LOW
CLOUDS PERSIST THROUGH THE TAF PERIOD. EXPECTING HIGH-END IFR CIGS
TO IMPROVE TO LOW-END MVFR THIS AFTERNOON AS LIFT FROM A SURFACE LOW
MOVES OUT OF THE AREA. FOR TONIGHT, DECREASING WINDS WITH AN
APPROACHING SURFACE HIGH WILL ALLOW FOR THE DEVELOPMENT OF MVFR FOG,
MAINLY AT KDBQ/KCID/KMLI. ADDITIONALLY, THE APPROACH OF A MID-LEVEL
SHORTWAVE/VORT MAX WILL LEAD TO A LOWERING OF CIGS, ESPECIALLY AT
KDBQ. ELSEWHERE, CONFIDENCE IS LOW AT THIS TIME OF THE POTENTIAL,
SO HAVE TRENDED WITH A SCT007 AT REMAINING SITES IN THIS TAF.
HYDROLOGY
ISSUED AT 212 PM CST SAT JAN 25 2020
ICE ON THE MISSISSIPPI RIVER IS CAUSING FLOODING CONCERNS NEAR THE
QUAD CITIES. POOL 16 CURRENTLY HAS THE MOST IMPACTS FROM THIS ICE.
EVEN THOUGH THE RIVER HAS DROPPED AT THE RCKI2 GAUGE, REPORTS FROM
EM STILL HAVE FLOODING ON ENCHANTED ISLAND. THIS WILL LIKELY
CONTINUE UNTIL THE ICE BREAKS UP. THE EXACT TIME THAT THE ICE WILL
BREAK UP IS HARD TO ASCERTAIN.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SYNOPSIS...SPECK
SHORT TERM...SPECK
LONG TERM...GIBBS
AVIATION...SPECK
HYDROLOGY...GIBBS
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