150
FXUS63 KDVN 021617
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1017 AM CST SUN MAR 2 2025
..UPDATED FOR 18Z AVIATION
KEY MESSAGES
- SLIGHTLY WARMER TODAY WITH SUN, BEFORE A SLIGHT CHANCE
(15-30%) OF RAIN/FREEZING RAIN/SNOW MOVES INTO THE AREA FOR
DAYBREAK
- STRONG STORM SYSTEM STARTING TUESDAY AND LASTING INTO
WEDNESDAY ON TRACK TO AFFECT THE AREA.
- EARLY WEEK STORM WILL FEATURE HEAVY RAIN, POTENTIAL FLASH
FLOODING, STRONG WINDS, SOME THUNDERSTORMS. SEVERE WEATHER
CANNOT BE RULED OUT AT THIS TIME.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 313 AM CST SUN MAR 2 2025
SURFACE HIGH PRESSURE IS EXPECTED TO AFFECT THE AREA TODAY. THE
HIGH IS EXPECTED TO SLIDE EAST OF THE AREA THIS AFTERNOON WITH
IT LOW LEVEL FLOW IS EXPECTED TO BECOME SW LEADING TO WAA INTO
THE AREA. THIS WILL WARM TEMPERATURES INTO THE 40S ACROSS THE
AREA. AT THE SAME TIME, MOISTURE WILL SLOWLY INCREASE AS WELL.
OVERALL TODAY WILL BE THE LAST QUIET WEATHER DAY FOR THE REST OF
THE WEEK.
TONIGHT, A FGEN BAND MOVES INTO THE AREA WITH THE WAA. MOISTURE
ALOFT WITH THE WAA BAND WILL MOVE INTO THE AREA OVERNIGHT
LEADING TO THE ARRIVAL OF CLOUDS. AT THE SAME TIME, LOW LEVEL
MOISTURE LOOKS TO BE LAGGING THIS FGEN BAND. IN MOST CASES,
WOULD PROBABLY ADD SPRINKLES IN THIS SETUP. HOWEVER, CAMS
CONTINUE TO SHOW SHOWERY LIKE RETURNS. THIS CONTINUES TO SUGGEST
THAT SOME OF THE RAIN/FZRA/SNOW COULD REACH THE GROUND. WITH
CURRENT SURFACE TEMPS THINK MOST OF THIS WILL BE RAIN. AS IT
PULLS NORTH, THERE IS A POTENTIAL FOR TEMPS TO BE BELOW FREEZING
AFTER 12Z MONDAY. HOWEVER, WITH THE SUN COMING UP DON'T THINK
THERE WILL BE MUCH OF A THREAT FOR ACCUMULATION. AT THIS TIME,
WILL BE DOWNPLAYING THIS FZRA/SNOW THREAT WITH THE PRECIP
TONIGHT. HIGHS WILL BE NOTICEABLY WARMER ON MONDAY AND MAINLY
IN THE 50S AIDED BY BREEZY SOUTHERLY WINDS.
LONG TERM /MONDAY THROUGH SATURDAY/
ISSUED AT 313 AM CST SUN MAR 2 2025
ALL ATTENTION TURNS TO THE STRONG STORM SYSTEM TUESDAY INTO
WEDNESDAY. THIS SYSTEM IS LIKELY TO BRING IMPACTFUL WEATHER
ACROSS OUR AREA. A POTENT DEEPENING SURFACE LOW IS FORECAST TO
TRACK ACROSS THE AREA TUESDAY INTO WEDNESDAY BEFORE OCCLUDING TO
OUR NE. FORECAST GUIDANCE IS STILL ON TRACK SHOWING A SUB 990
HPA LOW. AS EARLIER SHIFTS MENTIONED, THIS CONTINUES SHOW MSLP
AS A 'MIN' ON THE NAEFS, WHICH INDICATES THE EVENT FALLS OUT OF
THE 30 YEAR MODEL CLIMATOLOGY. A SHORTWAVE DRIVING THIS LOW WILL
SWING NEGATIVELY TILTED AS IT MOVES INTO OUR AREA TUESDAY,
FORCING A WARM SECTOR INTO OUR SOUTHERN CWA. THIS SYSTEM HAS ALL
THE HALLMARKS OF BEING IMPACTFUL FOR OUR AREA.
AS FAR AS IMPACTS GO, WIND AND RAIN WILL LIKELY BE THE MAIN
IMPACTS FOLLOWED BY SNOW ON THE BACKSIDE OF THE SYSTEM AND THE
POTENTIAL FOR HSLC TORNADOES TUESDAY AFTERNOON INTO THE EVENING.
FOCUSING ON RAIN FIRST, STRONG MOISTURE ADVECTION ASSOCIATED
WITH THE DEEPENING LOW AND UPPER LEVEL SHORTWAVE WILL BRING WELL
ABOVE NORMAL PWATS INTO OUR AREA. THIS WILL CONTINUE WELL INTO
TUESDAY NIGHT AND WEDNESDAY AS THE WRAP AROUND AND TROWAL FROM
THE SYSTEM MOVES ACROSS THE AREA AS WELL. LOOKING AT POTENTIAL
RAINFALL AMOUNTS, THE 25TH TO 75TH PERCENTILE FOR THE 48 HR
PERIOD ENCOMPASSING THE STORM RUNS FROM 1 TO 2 INCHES AREAWIDE.
LOOKING AT THE 90TH PERCENTILE PUTS THE AREA IN A SWATH OF 2 TO
3 INCHES. WITH A FROST DEPTH OF 8 INCHES, MOST OF THIS RAIN WILL
TURN TO RUNOFF, LIKELY LEADING TO FLASH FLOODING AND RISES ON
AREA RIVERS AND STREAMS. WE DO HAVE A HAVE ABOUT 24 TO 36 HOURS
OF ABOVE FREEZING TEMPS BEFORE THE SYSTEM MOVES IN, SUGGESTING
THAT SOME OF THE TOP OF THE FROST DEPTH WILL GO AWAY. SO 'SOME'
OF THE RAIN WILL BE ABSORBED. THIS REALLY DEPENDS ON RAINFALL
RATES AND I THINK WE WILL SEE RATES INCREASES AS THE DAY GOES ON
TUESDAY. WE WILL NEED TO KEEP AN EYE ON THE NEED FOR A FLOOD
WATCH FOR FLASH FLOODING.
NOW LOOKING AT THE WINDS, WITH SUCH A STRONG STORM SYSTEM, WE
LOOK TO HAVE SUSTAINED WINDS AND GUSTS WELL INTO THE WIND
ADVISORY LEVEL AS GUSTS NEAR 45 KTS SEEM LIKELY. IN FACT, SOME
OF THE GUIDANCE SUGGESTS EVEN STRONGER WINDS. WITH RAINFALL, AND
SATURATED SOILS, WE MAY SEE SOME SMALL TREES COMING DOWN AS WELL
JUST WITH THE GRADIENT WINDS.
THE SNOW: ON THE BACKSIDE OF THE SYSTEM LATER TUESDAY NIGHT AND
WEDNESDAY, THERE IS THE POTENTIAL FOR RAIN TO CHANGE TO A
PERIOD OF WET POSSIBLY HEAVY SNOW WITH THE DEFORMATION ZONE AND
TROWAL, AS LOW LEVEL COLDER AIR FILTERS IN. IN ADDITION, STRONG
WINDS WOULD BE PLAUSIBLE AND THE COMBINATION COULD HAVE
SIGNIFICANT IMPACTS TO TRAVEL.
AS FAR AS HSLC TORNADOES GOES, ENSEMBLE DATA HAS 200-500 J/KG
SBCAPE WITH A 100-200 0-3KM CAPE. THIS IS MORE THAN SUFFICIENT
FOR KINEMATICS RELATING TO A TORNADO RISK. LOOKING AT THE SHEAR
SOME 30KTS IN THE 0-1KM LEVEL SUGGESTS THE RISK FOR ROTATION.
SPC HAS A MARGINAL RISK CLOSE TO OUR SOUTHERN CWA FOR DAY 3. THE
MAIN QUESTION HERE IS HOW FAR NORTH DOES THE WARM SECTOR GET.
THIS WILL DICTATE THE AREA FOR THE TORNADO THREAT. RIGHT NOW THE
BEST CHANCE LOOKS TO BE SOUTH OF I-80 AND NEAR THE STATE LINE
WITH MO.
ALL IN ALL, A VARIETY OF POTENTIAL IMPACTFUL WEATHER HEADING
TOWARD MIDWEEK THAT WE ENCOURAGE ALL TO STAY TUNED TO THE
FORECAST!
BEYOND, WE LOOK TO REMAIN ACTIVE WITH ANOTHER SYSTEM POTENTIALLY
FRIDAY INTO SATURDAY WITH RAIN/SNOW.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1015 AM CST SUN MAR 2 2025
PREDOMINANTLY VFR CONDITIONS ARE ANTICIPATED, WITH WINDS TURNING
SOUTHERLY AT 5-10 KT THEN INCREASING TO 10-15 KT WITH GUSTS
AROUND 20 KT ON MONDAY. LATE TONIGHT AND MONDAY MORNING MARGINAL
LLWS IS POSSIBLE, AS WINDS STRENGTHEN FROM SSW TO AROUND 30 KT
NEAR 2KFT AGL. ATTENDANT TO THIS WILL BE A SURGE IN ELEVATED
MOISTURE LEADING TO AN INCREASE IN CLOUDS (CIGS MAINLY ABOVE 3-4KFT
AGL) AND SPOTTY RAIN SHOWERS THAT HAVE BEEN HANDLED WITH PROB30
MENTION. CAN'T RULE OUT A VERY BRIEF PERIOD OF FREEZING RAIN WHERE
TEMPS ARE HOVERING AROUND THE FREEZING MARK (MAINLY NORTH OF I-80),
BUT THE MARGINAL TEMPS SHOULD WARM QUICKLY OWING TO MINIMAL IF ANY
IMPACTS.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...GIBBS
LONG TERM...GIBBS
AVIATION...MCCLURE
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