941
FXUS63 KSGF 152207 CCA
AFDSGF
AREA FORECAST DISCUSSION...CORRECTED
NATIONAL WEATHER SERVICE SPRINGFIELD MO
407 PM CST SUN DEC 15 2024
KEY MESSAGES
- MARGINAL (1 OF 5) RISK FOR SEVERE THUNDERSTORMS TONIGHT. THE
GREATEST RISK WILL BE ALONG AND SOUTH OF I-44 WITHIN A 60-90%
CHANCE OF SHOWERS AND THUNDERSTORMS. THE SEVERE THREAT WILL
BE ISOLATED AT BEST, BUT MAXIMUM POTENTIAL HAZARDS INCLUDE
HAIL UP TO HALF DOLLARS, 50-60 MPH WIND GUSTS, AND AN ISOLATED
TORNADO OR TWO NOT BEING RULED OUT.
- NEXT CHANCE OF RAIN OCCURS TUESDAY NIGHT (30-60%). HIGHEST
CHANCES ACROSS SOUTH-CENTRAL MISSOURI.
- ABOVE NORMAL TEMPERATURES THROUGH TUESDAY, THEN TRENDING TO
NEAR NORMAL THROUGH END OF THE WEEK.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 330 PM CST SUN DEC 15 2024
CURRENT WATER VAPOR IMAGERY PAIRED WITH RAP ANALYSIS DEPICTS TWO
SHORTWAVES TRAVERSING THE CONUS. ONE COMPACT SHORTWAVE IS MOVING
ACROSS THE LOWER GREAT LAKES, WHILE ANOTHER IS PROGRESSING WEST
THROUGH THE NORTHERN PLAINS. MISSOURI IS PLACED UNDERNEATH THE
RISING HEIGHTS IN BETWEEN THE TWO WAVES. THE RISING HEIGHTS ARE
A RESULT OF STRONG WARM AIR ADVECTION FROM THE SURFACE THROUGH
700 MB. THIS IS ALLOWING TEMPERATURES TO REACH THE UPPER 50S TO
THE UPPER 60S.
TWO SURFACE WARM FRONTS ARE ASSOCIATED WITH THE WARM AIR
ADVECTION. ONE IS STRETCHED ACROSS EAST-CENTRAL NE/KS AND INTO
WEST-CENTRAL MO. ANOTHER IS LIFTING NORTH OUT OF CENTRAL AR/OK.
ALONG THE WARM FRONT IN MUCH OF ARKANSAS, DRIZZLE IS CURRENTLY
ONGOING, MARKING THE FRONT OF LOW-LEVEL MOISTURE RETURN. PWATS
ALONG THE SOUTHERN MO BORDER QUICKLY INCREASES FROM 0.5" TO THE
1.25.1.5" RANGE IN CENTRAL AR WHERE THE DRIZZLE IS OCCURRING.
MARGINAL (1 OF 5) RISK FOR SEVERE THUNDERSTORMS TONIGHT:
THE AR WARM FRONT IS FORECAST TO QUICKLY LIFT THROUGH OUR REGION
THIS EVENING AND INTO TONIGHT. NEAR-SATURATED LOW-LEVELS, UPWARD
OMEGA AIDED BY SOUTHERLY UPSLOPE FLOW ALONG THE OZARK PLATEAU,
NO CHANCE OF CLOUD ICE, AND A SURFACE INVERSION WILL ALLOW
DRIZZLE TO CONTINUE AS IT LIFTS INTO THE AREA AFTER 5-6 PM.
DRIZZLE WILL BE THE PREDOMINANT PRECIPITATION TYPE BEFORE
LARGE-SCALE ASCENT AHEAD OF THE MID-LEVEL TROUGH OVERSPREADS THE
WARM SECTOR, FORCING SCATTERED TO NUMEROUS SHOWERS ALONG AND
SOUTH OF I-44 AFTER 9 PM (30-60% CHANCE). A FEW RUMBLES OF
THUNDER ARE POSSIBLE WITH THIS ACTIVITY.
ONCE THE COLD FRONT APPROACHES, COVERAGE IN SHOWERS AND
THUNDERSTORMS IS EXPECTED TO INCREASE AFTER 11PM-1AM,
ESPECIALLY ALONG AND SOUTH OF I-44 WHERE MOISTURE AND
INSTABILITY WILL BE MARGINALLY HIGHER (60-90% CHANCE). WITH THIS
ACTIVITY, THERE IS A MARGINAL (1 OF 5) RISK FOR SEVERE
THUNDERSTORMS ALONG AND SE OF A SPRINGFIELD TO JOPLIN LINE
(WHICH INCLUDES BRANSON). COVERAGE OF SEVERE THUNDERSTORMS IS
EXPECTED TO BE EVEN MORE ISOLATED (~5-10% CHANCE).
THE THREAT OF SEVERE WEATHER AND ITS ASSOCIATED HAZARDS ARE VERY
CONDITIONAL AND DEPENDENT ON THE DEGREE OF INSTABILITY, AND HOW
SURFACE-BASED STORMS GET. MUCAPE IS EXPECTED TO REACH 500-1000
J/KG TONIGHT, WHICH IS ENOUGH THUNDERSTORMS. A 40-50 KT DYNAMIC
AND NOCTURNAL LOW-LEVEL JET WILL ALSO MOVE IN TONIGHT. ABOVE
THIS JET, HOWEVER, WIND DIRECTION AND SPEED BARELY CHANGES. THIS
MEANS 0-6 KM SHEAR WILL REACH 40-50 KTS (SUFFICIENT FOR
SUPERCELLS), BUT 1-6 KM SHEAR WILL BE A MEASLY 5-15 KTS.
THEREFORE, IF STORMS ARE PRETTY ELEVATED (ROOTED AROUND OR JUST
BELOW 1 KM), STORMS WILL BE WEAK. BUT IF STORMS ARE ABLE TO ROOT
AT THE SURFACE, ISOLATED SEVERE STORMS, INCLUDING SUPERCELLS,
ARE POSSIBLE. THIS MEANS THAT THE MINIMUM HAZARDS FOR TONIGHT
COULD BE HEAVY RAIN TO SMALL HAIL (POTENTIALLY COPIOUS AMOUNTS
OF SMALL HAIL GIVEN MUCH OF THE MUCAPE IN AN ELONGATED HAIL
GROWTH ZONE). THE MAXIMUM HAZARDS FOR TONIGHT WOULD BE HAIL UP
TO HALF DOLLARS AND WIND GUSTS UP TO 50-60 MPH. AN ISOLATED
TORNADO OR TWO CANNOT BE RULED OUT EITHER IF STORMS ARE SURFACE
BASED, THANKS TO 30-40 KTS OF 0-1 KM SHEAR WITH 50-100 J/KG RAP
MLCAPE. HOWEVER, SATURATED LOW-LEVELS WILL LIMIT SURFACE LAPSE
RATES, GREATLY INHIBITING THE THREAT FOR WIND GUSTS AND
TORNADOES, EVEN IF SURFACE-BASED. THE THREAT FOR SEVERE STORMS
WILL GENERALLY BE BEFORE 6 AM OR SO.
ABOVE NORMAL TEMPERATURES MONDAY:
ALL RAIN SHOULD CLEAR THE AREA BY MID-MORNING. DESPITE THE COLD
FRONT CLEARING THROUGH, IT WILL NOT MAKE IT VERY FAR SOUTH
DURING THE DAY MONDAY, ALLOWING HIGHS TO STAY IN THE MIDDLE 50S
TO LOWER 60S. LOWS MONDAY NIGHT WILL BE IN THE MIDDLE 30S.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 330 PM CST SUN DEC 15 2024
ABOVE NORMAL TEMPERATURES THROUGH TUESDAY:
WITH THE WAVE AND JET STREAM LIFTING NORTH AND STAYING OUT OF
OUR AREA, THE SURFACE COLD FRONT WILL NOT MAKE IT VERY FAR
SOUTH. RECENT DETERMINISTIC MODELS LIFT THE BOUNDARY BACK
THROUGH OUR AREA TUESDAY AHEAD OF THE NEXT SYSTEM TUESDAY NIGHT.
ALL THIS WILL KEEP HIGH TEMPERATURES ABOVE NORMAL TUESDAY WITH
HIGHS IN THE MIDDLE TO UPPER 50S AND LOWS IN THE MIDDLE TO UPPER
30S.
NEXT CHANCE OF RAIN COMES TUESDAY NIGHT (30-60% CHANCE):
THE NEXT WAVE WILL BE A BIT MORE DYNAMIC WITH A MORE ELONGATED
TROUGH AXIS AND PV FINGER. THIS WILL BRING ANOTHER SURFACE COLD
FRONT THROUGH THE AREA, FORCING ANOTHER ROUND OF RAIN. MOISTURE
RETURN AHEAD OF THIS SYSTEM WILL BE MORE MODEST WITH ONLY A
SMALL WINDOW BETWEEN THE EXIT OF MONDAY'S SYSTEM AND THE
ENTERING OF THIS ONE. THEREFORE, CHANCES ARE A BIT LOWER AT
30-60% WITH LOWER PRECIPITATION AMOUNTS (GENERALLY LESS THAN
0.5"). THE HIGHEST CHANCES WILL BE IN SOUTH-CENTRAL MO.
WITH MORE MEAGER MOISTURE RETURN, THUNDERSTORM CHANCES WILL ALSO
BE LOWER. LATEST SREF GUIDANCE ONLY GIVES A 10-30% CHANCE FOR
MUCAPE >100 J/KG, WITH MEAN VALUES AT 50-75 J/KG. IF
THUNDERSTORMS WERE TO DEVELOP, THE BEST CHANCE FOR THEM WOULD BE
ALONG AND SOUTH OF I-44. SEVERE WEATHER IS NOT EXPECTED AT THIS
TIME WITH THIS SYSTEM. EVEN IF INSTABILITY WERE TO OVERPERFORM
THE CURRENT MODEL OUTPUT, DEEP-LAYER SHEAR IS LIKELY (80-90%)
TO STAY BELOW 30 KTS.
TRENDING TO NEAR NORMAL THROUGH END OF THE WEEK:
WITH A MORE ELONGATED TROUGH AXIS, AND THE SOUTHEAST DIGGING
PATH OF THE WAVE, THE SURFACE COLD FRONT WILL MAKE IT WELL
THROUGH OUR AREA, BRINGING BACK COOLER AIR. THIS WILL BRING
TEMPERATURES BACK TO THE NORMAL RANGE THROUGH THE END OF NEXT
WEEK. HIGHS WILL GENERALLY BE IN THE 40S WITH LOWS IN THE 20S.
IT WILL BE A COOLING TREND, SO HIGHS WILL BE IN THE UPPER 40S
WEDNESDAY AND THURSDAY, AND DOWN INTO THE UPPER 30S TO LOWER 40S
NEXT WEEKEND. LOWS WILL FOLLOW THE COOLING TREND WITH UPPER 20S
MIDWEEK, AND LOWER 20S NEXT WEEKEND.
THERE IS CERTAINLY POTENTIAL FOR LOWER TEMPERATURES THAN WHAT IS
CURRENTLY FORECAST FOR NEXT WEEKEND. NBM DETERMINISTIC IS CLOSER
TO THE 60TH PERCENTILE, WITH THE 25TH PERCENTILE HAVING HIGHS
IN THE LOWER TO MIDDLE 30S AND LOWS IN THE LOWER TO MIDDLE
TEENS. CLUSTER ANALYSIS SHOWS VERY STARK DIFFERENCES BETWEEN
ENSEMBLE SYSTEMS. THE ECMWF HAS A MUCH DEEPER AND COLDER TROUGH
MOVING THROUGH NEXT WEEKEND WHILE THE GEFS DOES NOT. WHICH
SOLUTION PLAYS OUT WILL DETERMINE HOW COLD TEMPERATURES GET.
AVIATION /18Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 1200 PM CST SUN DEC 15 2024
DETERIORATING AVIATION CONDITIONS WILL MOVE INTO ALL TAF SITES
AFTER 00Z. MEDIUM-HIGH CONFIDENCE THAT LOW CEILINGS AND DRIZZLE
WILL SURGE IN FROM THE SOUTH AFTER 00Z, LOWERING FLIGHT
CATEGORIES TO MVFR. CEILINGS WILL CONTINUE TO LOWER AND
SCATTERED TO NUMEROUS LIGHT SHOWERS SHOULD DEVELOP WITHIN THE
REGION AFTER 03Z (30-60% CHANCE), BRINGING CONDITIONS TO IFR. AS
A COLD FRONT DROPS IN FROM THE WEST, ISOLATED TO SCATTERED
THUNDERSTORMS MAY DEVELOP ALONG AND AHEAD OF THE FRONT (20-40%
CHANCE FOR SGF AND JLN, AND A 60-70% CHANCE FOR BBG). THE CHANCE
FOR SHOWERS AND STORMS WILL CLEAR ALL TAF SITES BY 10Z, LIKELY
EARLIER FOR JLN AND SGF.
ACCORDING TO THE 12Z HREF SUITE, THERE IS A LOW (10-30%) CHANCE
FOR PERIODS OF LIFR CEILINGS BETWEEN 00-15Z, ESPECIALLY FOR SGF
AND BBG. DURING THE FROPA, THE CHANCE INCREASES TO 50-70% RIGHT
ALONG THE FRONT (06-12Z FOR JLN; 9-13Z FOR SGF AND BBG). CLOUDS
SHOULD CLEAR THE AREA BY THE END OF THE TAF PERIOD.
LASTLY, WINDS WILL BEGIN OUT OF THE SOUTH AT 10-15 KTS WITH
GUSTS UP TO 20-25 KTS AT TIMES. THESE WILL SLOWLY SHIFT TO
WESTERLY OVERNIGHT DURING THE FROPA, SETTLING ON NORTHWESTERLY
BY 14Z.
SGF WATCHES/WARNINGS/ADVISORIES
KS...NONE.
MO...NONE.
SHORT TERM...PRICE
LONG TERM...PRICE
AVIATION...PRICE
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