802
FXUS63 KSGF 241149
AFDSGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SPRINGFIELD MO
549 AM CST TUE NOV 24 2020
SHORT TERM
(TODAY AND TONIGHT)
ISSUED AT 301 AM CST TUE NOV 24 2020
..SEVERE WEATHER THREAT TONIGHT..
GOES-16 WV IMAGERY EXHIBITS A MID-LEVEL SHORTWAVE TROUGH PUSHING
ACROSS THE FOUR CORNERS REGION EARLY THIS MORNING. THIS WAVE WILL
BEGIN TO LIFT AND PIVOT ACROSS THE MISSOURI OZARKS BY TONIGHT AS A
STRONG UPPER-LEVEL JET CORE NOSES INTO THE REGION FROM THE
SOUTHERN PLAINS. IN CONJUNCTION WITH THESE MID- AND UPPER-LEVEL
FEATURES, A SURFACE LOW- PRESSURE SYSTEM AND ITS ATTENDANT COLD
FRONT WILL MOVE ACROSS THE REGION LATE TONIGHT.
SURFACE WINDS WILL BE BREEZY TODAY AHEAD OF THE INCOMING FRONT
WITH NUMEROUS GUSTS TO 30 MPH. TEMPERATURES WILL BE NOTICEABLY
WARMER TODAY AS A MODIFIED GULF AIR MASS ADVECTS INTO THE AREA. WE
WENT ON THE WARMER SIDE OF GUIDANCE FOR TEMPERATURES THIS
AFTERNOON GIVEN THE ROBUST SURGE OF WARM AIR ADVECTION WITHIN THE
WARM SECTOR. THE NBM IS SUGGESTING AFTERNOON TEMPERATURES NEAR 60
DEGREES, WHICH CLOSELY RESEMBLES THE 90TH PERCENTILE OF ALL
AVAILABLE MODEL GUIDANCE.
HI-RESOLUTION MODEL GUIDANCE IS IN EXCELLENT AGREEMENT IN BREAKING
OUT SCATTERED SHOWERS ACROSS SOUTHEAST KANSAS AND THE MISSOURI
OZARKS BY EARLY AFTERNOON AS SHORTWAVE ENERGY AHEAD OF THE MAIN
WAVE RIPPLES INTO THE REGION ABOVE A BROAD AREA OF ISENTROPIC
ASCENT. THERE WILL LIKELY BE A FEW RUMBLES OF THUNDER EMBEDDED IN
THIS ACTIVITY, BUT THIS CONVECTION WILL BE ELEVATED AND POSE VERY
LITTLE SEVERE THREAT.
THINGS GET INTERESTING TONIGHT AS THE MAIN 500-MB SHORTWAVE PIVOTS
INTO THE OZARKS AND THE SURFACE LOW BECOMES OCCLUDED. SYNOPTIC
SCALE ASCENT WILL BE IMPRESSIVE ACROSS THE REGION AS THE FRONT
LEFT QUADRANT OF A STRONG UPPER-LEVEL JET CORE MAKES ITS WAY IN,
AND THE MID-LEVEL SHORTWAVE TAKES ON A NEGATIVE TILT. THESE
FEATURES WILL WORK IN TANDEM WITH A 50 KT LLJ AND BACKED SURFACE
WINDS NEAR THE TRIPLE POINT OF THE OCCLUDED LOW. DEEP-LAYER SHEAR
AND ENHANCED 0-1KM SRH WILL BE SUPPORTIVE OF ORGANIZED SEVERE
CONVECTION LATE TONIGHT NEAR THIS TRIPLE POINT.
THE MAIN FACTOR INHIBITING WIDESPREAD SEVERE CONVECTION ACROSS THE
OZARKS TONIGHT IS A LACK OF INSTABILITY. THE LATEST HREF MEAN
PROBABILITIES ARE SUGGESTING A VERY NARROW TONGUE OF 50-55F
DEWPOINTS ADVECTING NORTHWARD ALONG THE STRONGLY FORCED COLD
FRONT. THE HREF ALSO EXHIBITS SOME SURFACE-BASED INSTABILITY
(250-500 J/KG SBCAPE) ALONG THE FRONT, BUT IT'S UNCLEAR AT THIS
TIME IF THAT WILL BE ENOUGH FOR UPDRAFTS TO BE SUSTAINED.
THE TIMING FOR SEVERE WEATHER TONIGHT APPEARS TO BE BETWEEN 9PM
AND 3AM FOR LOCATIONS WEST OF HIGHWAY 65. ANY ORGANIZED
CONVECTION THAT DOES DEVELOP LATE TONIGHT WILL LIKELY FIZZLE EAST
OF HIGHWAY 65 AS THE NARROW TONGUE OF FAVORABLE THETA-E GETS
OVERTAKEN BY THE COLD FRONT.
THE RADAR MAY BECOME MESSY TONIGHT WITH A MIXED MODE OF
CONVECTION. ANY LOW-TOPPED SUPERCELLS THAT DEVELOP ACROSS EASTERN
KANSAS WOULD QUICKLY BECOME LINEAR GIVEN FAVORABLE 0-3KM SHEAR
MAGNITUDE AND DIRECTION. BECAUSE THERE IS A POSSIBILITY FOR
SUPERCELLS, QUARTER- SIZE HAIL REMAINS A POSSIBILITY. THE MORE
LIKELY SEVERE WEATHER HAZARD FOR TONIGHT WILL BE DAMAGING
STRAIGHT-LINE WINDS UP TO 60 MPH. A VERY LOW-END TORNADO THREAT
EXISTS ALONG THE TRIPLE POINT OF THE OCCLUDED FRONT, AS WELL AS
WITH ANY MESOVORTS THAT BECOME EMBEDDED IN A SQUALL LINE.
LONG TERM
(WEDNESDAY THROUGH MONDAY)
ISSUED AT 301 AM CST TUE NOV 24 2020
WEDNESDAY WILL BE COOLER AND CONTINUED BREEZY BEHIND THE COLD
FRONT. TEMPERATURES MAY BE WARMEST IN THE MORNING AND THEN
FLATLINE THROUGH THE REMAINDER OF THE DAY. FOR NOW, TEMPERATURES
IN THE MID-TO-UPPER 40S CAN BE EXPECTED WEDNESDAY AFTERNOON.
OVERNIGHT LOWS WILL BE NEAR FREEZING.
TEMPERATURES WILL REBOUND NICELY ON THURSDAY AS RETURN FLOW WORKS
BACK INTO THE REGION BENEATH A MID-LEVEL RIDGE. AFTERNOON HIGHS
WILL WARM TO NEAR 60 DEGREES. THEN, A DRY COLD FRONT WILL PUSH
ACROSS THE REGION BY FRIDAY, KNOCKING TEMPERATURES BACK DOWN NEAR
THE SEASONAL NORMS (DAILY HIGHS NEAR 50 AND OVERNIGHT LOWS NEAR
30). THE DRY STRETCH WILL EXTEND THROUGH THE HOLIDAY WEEKEND.
THE NBM IS SIGNALING AN IMPRESSIVE COLD SNAP BY EARLY NEXT WEEK
AS A TROUGH AMPLIFIES ACROSS THE NORTHERN PLAINS AND DIGS HARD
INTO THE OHIO VALLEY. THIS COULD PUSH DAILY HIGHS INTO THE LOW 40S
WITH OVERNIGHT LOWS IN THE 20S.
AVIATION
(FOR THE 12Z TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 534 AM CST TUE NOV 24 2020
VFR CEILINGS WILL CONTINUE THROUGH THE EARLY PART OF THIS TAF
PERIOD, BUT CEILINGS WILL GRADUALLY LOWER AHEAD OF AN INCOMING
COLD FRONT. MVFR FLIGHT CATEGORIES WILL BECOME WIDESPREAD AT JLN
BY 18Z, AND MORE WIDESPREAD AT SGF/BBG BY 00Z. WIDESPREAD SHOWERS
WILL BREAKOUT AHEAD OF THE FRONT AND ACCOMPANY THESE LOWER
AFTERNOON CEILINGS. SCATTERED THUNDERSTORMS WILL ALSO BE POSSIBLE
ALONG AND AHEAD OF THE FRONT.
SURFACE WINDS WILL BE BREEZY TODAY WITH SOUTHERLY WINDS GUSTING TO
25 KTS AT TIMES. THE WIND DIRECTIN WILL GRADUALLY VEER FROM SOUTH
TO WEST BEYOND 06Z AS THE COLD FRONT PUSHES THROUGH THE OZARKS.
DESPITE A FEW BREAKS IN THE CLOUDS BEYOND 06Z WEDNESDAY, IT WILL
BECOME MORE COMMON FOR CLOUDS TO FILL BACK IN AND LOWER TO IFR
CATEGORIES AS WRAP-AROUND MOISTURE FROM THE DEPARTING SYSTEM
HOVERS OVER THE OZARK PLATEAU.
SGF WATCHES/WARNINGS/ADVISORIES
MO...NONE.
KS...NONE.
SHORT TERM...ALBANO
LONG TERM...ALBANO
AVIATION...ALBANO
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