037
FXUS63 KDVN 171747
AFDDVN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1147 AM CST SUN NOV 17 2024
KEY MESSAGES
- CLOUDY DAY TODAY WITH A PASSING CHANCE (15-20%) OF A RAIN
SHOWER THROUGH THE DAY.
- STRONG STORM SYSTEM MONDAY WILL BRING RAIN, GUSTY WINDS, AND A
THREAT OF STRONG STORMS THROUGH THE EARLY MORNING ON TUESDAY.
- CLIPPER WEDNESDAY INTO THURSDAY WILL BRING WITH IT A RAIN/SNOW
MIX.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 252 AM CST SUN NOV 17 2024
COLD FRONT ASSOCIATED WITH THE SHORTWAVE THAT MOVED THROUGH THE
AREA LAST NIGHT IS EXPECTED TO SAG THROUGH THE AREA TODAY. WITH
THE UPPER LEVEL LOW MOVING NORTHEAST INTO THE AREA TONIGHT INTO
TOMORROW, FGEN ALONG THIS COLD FRONT COULD LEAD TO SPOTTY
SHOWERS THIS AFTERNOON AS THE FRONT MOVES ACROSS THE CWA. AS
WITH LAST NIGHT, OVERALL QPF WILL BE VERY LIGHT WITH ANY OF
THESE SHOWERS. THESE SHOWERS ARE NOT EXPECTED TO BE IMPACTFUL AT
ALL. NORTH OF THIS FRONT, ESPECIALLY ACROSS OUR NW CWA, SOME
CLEARING IS EXPECTED POST FRONTAL. TEMPERATURES WILL LIKELY NOT
CHANGE ALL THAT MUCH ACROSS THE AREA FROM NOW THROUGH SUNSET.
SOUTH OF THE COLD FRONT, TEMPERATURES INTO UPPER 50S AND LOW
60S ARE POSSIBLE. THIS FRONT STALLS ACROSS THE AREA TONIGHT.
TONIGHT, THERE IS A CHANCE FOR PATCHY FOG AS THE COLD FRONT FROM
TODAY WILL NOW BECOME STATIONARY. WAA AND MOISTURE ADVECTION
BEGINS IN EARNEST OVERNIGHT WITH THE APPROACHING MID LATITUDE
STORM SYSTEM. MOST OF THE AREA WILL BE DRY TONIGHT.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 252 AM CST SUN NOV 17 2024
OVERALL, THE FORECAST TRACK OF THE STORM SYSTEM ON MONDAY HAS
MOVED SLIGHTLY WEST. AN UPPER LEVEL LOW IS EXPECTED TO MOVE
NORTHEAST INTO THE AREA DURING THE DAY AND INTO THE EVENING,
SWINGING NEGATIVELY TILTED AS IT MOVES OVER OUR AREA. WARM
FRONTAL CONVECTION IS EXPECTED TO AFFECT THE AREA FIRST. THE
MAIN SURFACE LOW WILL MOVE ACROSS WESTERN IOWA/EASTERN NE AS
THE WARM SECTOR PULLS INTO OUR AREA IN THE EVENING. THIS FILLING
LOW WILL KEEP MUCH OF THE DEFORMATION PRECIP WEST OF OUR AREA. A
STRONGER PRESSURE GRADIENT, OF AROUND 12 HPA IS FORECAST ON
MONDAY. THIS WILL LEAD TO WIND GUSTS IN THE LOW 30 KNOT RANGE.
IF THIS TREND CONTINUES, WE MAY BE LOOKING AT THE NEED FOR A
WIND ADVISORY.
WHAT REMAINS CONSISTENT IS THE FOOTPRINT OF THE 1+ RAINFALL
TOTALS IN THIS SYSTEM. ENSEMBLE SYSTEMS HAVE PROB OF EXCEEDING 1
INCH MAINLY WEST OF THE MISSISSIPPI RIVER. THESE RAINFALL TOTALS
DROP OF QUICKLY AS YOU MOVE EAST INTO ILLINOIS. ECMWF SHIFT
TAILS HAS THE BETTER CHANCE FOR ANOMALOUS PRECIPITATION WELL
SOUTH AND WEST OF OUR AREA. NONETHELESS, THE RAIN WE ARE
FORECAST TO GET WILL BE WELL NEEDED. THAT SAID, RAIN WITH WINDS
GUSTING TO 35 MPH WILL MAKE FOR A PRETTY AWFUL START TO THE WORK
WEEK.
AS FAR AS HSLC TORNADOES GO, OVERALL CONCERN HAS NOT CHANGED. IF
ANYTHING CONFIDENCE IN THE SETUP OCCURRING HAS ONLY INCREASED.
RELEVANT TO TODAY'S CONVERSATION ARE THE THREE POINTS MADE LAST
NIGHT; 1. WE HAVE AN ADVANCING WARM FRONT ACROSS THE AREA. MANY
OF OUR TORNADOES OCCUR WITH THIS. 2. THE LOW LEVEL HODOGRAPH
SHOWS STRONG CURVATURE IN THE LOW LEVELS AND IT WOULD NOT TAKE
MUCH TO GET CELL TO ROTATE. 3. WINDS WILL STAY ELEVATED MEANING
WE WILL REMAIN MIXED WELL INTO THE OVERNIGHT AS A MORE JUICED
ENVIRONMENT MOVES INTO OUR AREA. THE CSU MACHINE LEARNING SEVERE
PROBS HAVE CONTINUED TO INCREASE THE 2% TOR PROBS INTO OUR AREA,
AND ARE NOW I-80 SOUTH. SOME GUIDANCE BRINGS SBCAPE UP TO 500
J/KG BETWEEN 00Z AND 06Z TUESDAY (THAT IS GETTING TO WHERE WE
ARE ABOVE THE HSLC PARAMETER SPACE AND JUST INTO MINI SUPERCELL
LAND). MODEL SOUNDINGS HAVE COMPLETELY UNSTABLE PARCELS WITH
FAT CAPE IN THE LOWEST 2KM OF THE SOUNDING. THE 00Z CSHIELD
GUIDANCE NOW HAS A LINE OF BROKEN CELLS AT 03Z MOVING ACROSS OUR
CWA. NOT TO MENTION, SPC HAS TRENDED THE MRGL FURTHER NORTH AS
WELL. IF WE DO GET THE CONVECTION CSHIELD SHOWS THEN IT WILL BE
VERY SHALLOW. IF THE MODEL SOUNDINGS VERIFY, WE ARE LOOKING AT
VERY LOW TOP CONVECTION WHERE ROTATION WILL BE IN THE LOWEST 2KM
OF THE ATMOSPHERE. WITH HSLC CASES, WE ARE TALKING ABOUT SUCH
SMALL VALUES OF CAPE THAT THE WINDOW FOR SEVERE IS SO SMALL.
REGARDLESS, WE HAVE TO KEEP A CLOSE EYE ON THIS, ESPECIALLY
SINCE MORE CAMS ARE STARTING CAPTURE THIS FORECAST WINDOW TODAY
AND INTO TOMORROW. WILL CONTINUE TO MENTION STRONG STORMS
POSSIBLE IN THE HWO FOR MONDAY. IT WON'T TAKE MUCH TO GET
STRONGER WINDS IN DOWNDRAFTS TO SURFACE SO COULD SEE
STRONG/SEVERE WINDS EVEN WITHOUT TOR THREAT.
NOW, WEDNESDAY. A SERIES OF CLIPPERS IN QUICK SUCCESSION WILL
OVERSPREAD THE AREA. THERE REMAINS DIFFERENCES IN THE QPF
FOOTPRINT AND TRACK OF THESE CLIPPERS. NONETHELESS, THE THERMAL
PROFILES SUGGEST THAT OVERNIGHT WE SEE SOME RAIN/SNOW MIXES
BEFORE TURNING TO RAIN DURING THE DAY ON THURSDAY. PROB OF
EXCEEDING ONE INCH OF SNOW IS PRETTY MUCH NIL, SO THAT MEANS
SNOWFALL RATES WILL LIKELY BE LOW AND THE WARM GROUND WILL WIN
OUT. WE MAY SEE SOME SLICK SPOTS ON BRIDGES AND OVERPASSES SINCE
THEY COOL QUICKER. BUT AT THIS TIME, STILL NOT SURE THE AREA
SEES ANY QPF.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1135 AM CST SUN NOV 17 2024
A COLD FRONT IS MOVING EASTWARD ACROSS EASTERN IOWA AND
NORTHWEST ILLINOIS LATE THIS MORNING WITH WEST WINDS OF 5 TO 10
KNOTS. CONDITIONS ARE FORECAST TO BE VFR TODAY WITH MAINLY MID
AND HIGH CLOUDS ASSOCIATED WITH THIS INITIAL STORM SYSTEM. RAIN
SHOWERS ARE POSSIBLE THIS AFTERNOON AT KMLI AND KBRL BUT
CONFIDENCE IS LOW ON THE TIMING AND LOCATION.
A STORM SYSTEM IS FORECAST TO DEVELOP ACROSS OKLAHOMA AND TEXAS
LATE TONIGHT INTO MONDAY. CEILINGS WILL LOWER TO MVFR AFTER 06
UTC AND THEN TO IFR AS RAIN BEGINS BY 12 UTC> WINDS WILL BECOME
EASTERLY LATE IN THE PERIOD WITH INCREASING SPEEDS.
DVN WATCHES/WARNINGS/ADVISORIES
IA...NONE.
IL...NONE.
MO...NONE.
SHORT TERM...GIBBS
LONG TERM...GIBBS
AVIATION...COUSINS
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