670
FXUS63 KEAX 181119
AFDEAX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE KANSAS CITY/PLEASANT HILL MO
619 AM CDT SUN MAY 18 2025
..UPDATED 12Z AVIATION
KEY MESSAGES
- SCATTERED THUNDERSTORMS THIS MORNING; STRONGER ACTIVITY THIS
EVENING
- SEVERE THUNDERSTORMS CAPABLE OF ALL HAZARDS MONDAY
- LINGERING STORMS POSSIBLE TUESDAY MORNING, SEVERE THREAT MORE FOR
EASTERN AND SOUTHEASTERN MISSOURI
- HEAVY RAINFALL MONDAY AND TUESDAY COULD CAUSE FLOODING
DISCUSSION
ISSUED AT 232 AM CDT SUN MAY 18 2025
DEEP H5 TROUGH AXIS HAS BEEN DIGGING INTO THE FOUR CORNERS REGION AS
A THE JET STREAK ASSOCIATED WITH IT ROUNDS THE BASE OF THE TROUGH.
THIS WILL START TO LIFT OUT OF THE FOUR CORNER REGIONS BY LATE THIS
MORNING. THIS HAS PROMPTED A MODEST H5 HEIGHT RISE RESPONSE OVER THE
HIGH PLAINS DURING THE OVERNIGHT HOURS, BUT A FEW VORT MAXIMA HAVE
MOVED THROUGH THE FLOW, AND WAS ABLE TO GENERATE ENOUGH UPPER-LEVEL
DIVERGENCE TO PROMOTE LIFT. THIS IS WHAT HELPED TO STRENGTHEN
CONVECTION IN OUR SOUTHWESTERN COUNTIES DURING THE OVERNIGHT HOURS
ALONG THE NOSE OF STRONGER WAA. WE SHOULD SEE A FEW HOURS OF MODEST
MID-LEVEL HEIGHT RISES BY LATE MORNING THAT HELPS TO PUSH THIS
ACTIVITY EASTWARD, ALTHOUGH CONTINUED WAA AND ISENTROPIC ASCENT MAY
GENERATE NEW ACTIVITY. CAM GUIDANCE OVERNIGHT SO FAR THOUGH HAS KEPT
MOST OF THIS FORCING CLOSER TO THE INTERSTATE 44 CORRIDOR THOUGH, AS
THIS IS WHERE BETTER MOISTURE TRANSPORT HAS OCCURRED OVER THE PAST
12-15 HOURS. HEADING INTO THE AFTERNOON, H5 TROUGH LIFTS AND
ACQUIRES A NEGATIVE TILT AS IT MOVES ACROSS THE ROCKIES. STRONG DCVA
HAS ALREADY BEEN OCCURRING OVER THE FRONT RANGE AND FAR WESTERN
PORTIONS OF THE HIGH PLAINS IN RESPONSE TO THE APPROACHING TROUGH
PROMPTING STRONGER SURFACE CYCLOGENESIS. THIS WILL CONTINUE TO
INCREASE LOWER-LEVEL TROPOSPHERIC FLOW ALONG WITH STRONG THETA-E
TRANSPORT FROM THE SOUTHERN PLAINS INTO THE LOWER MISSOURI RIVER
VALLEY, FORCING A THERMAL RIDGE THROUGH MOST OF THE AREA. STRONGER
EML DEVELOPS FROM CENTRAL KANSAS AND WESTWARD, WHICH SHOULD LEAVE
ONLY UPPER-LEVEL THIN CLOUD COVER FROM CENTRAL KANSAS TO WESTERN
KANSAS. BY THE AFTERNOON, STRONG MIXING SHOULD COMMENCE AS DAYTIME
HEATING CONTINUES, RESULTING IN A PROMINENT DRYLINE MOVING ACROSS
CENTRAL KANSAS. EXPECTING MULTIPLE VORT MAXIMA TO EJECT OFF THE MAIN
TROUGH WESTWARD THAT WILL BE LIFTING OUT OF THE ROCKIES THAT SHOULD
INCREASE ASCENT ACROSS MUCH OF THE CENTRAL PLAINS. EVENTUALLY
CONVERGENCE STRENGTHENS IN THE CENTRAL PLAINS AS THE DRYLINE MIXES
EAST OF INTERSTATE 135/US HWY. 81. HRRR AND RAP SOUNDINGS INDICATE A
FAIRLY STRONG CAP DUE TO THE STRENGTH OF THE EML. BUT AS THE SURFACE
CYCLONE MATURES AND PREVIOUSLY MENTIONED VORT MAXIMA MOVE THROUGH,
THE DRYLINE CONVERGENCE SHOULD EVENTUALLY PUSH UP AGAINST A HIGHER
THETA-E AIRMASS, AND THERE SHOULD BE ENOUGH FORCING AND MOISTURE TO
WORK THROUGH ANY CAP THAT MAY BE IN PLACE. ALONG THE KS-MO STATE
LINE AND EASTWARD, THE CAP REMAINS VERY STRONG, EVEN THOUGH THE WAA
HELPS BRING IN AIRMASS WITH MUCAPE INCREASING BEYOND 2500 J/KG. CIN
VALUES FOR MOST OF OUR AREA ARE AT LEAST -100 J/KG, AND THE FURTHER
EAST-NORTHEAST GOES TO AROUND -200 J/KG. THEREFORE, EVEN WITH
SURFACE PRESSURE FALLS/TROUGHING EXTENDING EASTWARD WITH THE
MATURING CYCLONE, THE FORCING WILL NOT BE AS STRONG IN OUR COUNTIES
AS IT WILL BE TOWARD THE KANSAS FLINT HILLS. THEREFORE, MOST OF THE
SUNDAY EVENING ACTIVITY FORECAST FOR OUR AREA, WILL BE THE RESULT
STORMS OVER KANSAS CONGEALING AS THE LLJ KICKS IN. OUR CURRENT
THINKING IS THE THREAT FOR DISCRETE SUPERCELLS REMAINS WELL WEST OF
OUR AREA, THOUGH A STRONGER STORM MAY TRY TO TRACK CLOSE BY. ONCE
STORMS CONGEAL OVER EASTERN KANSAS AND PROPAGATES INTO OUR WESTERN
COUNTIES, WIND SHEAR INCREASES AND STRONGER COLD POOLS MAY BE ABLE
TO BALANCE ENOUGH FOR AN MCS TO PRESENT A DAMAGING WIND THREAT, AND
MAY EVEN SEE SOME ENHANCED UPDRAFTS CAPABLE OF PRODUCING LAGER HAIL
AS A COMPLEX MOVES IN. WILL NEED TO MONITOR LLJ TRENDS. GIVEN THE
DRY AIR ASSOCIATED WITH THE DRYLINE, IF INITIATION AND STORM
CONGEALING TIMES ALIGNS RIGHT, THERE MAY BE ENOUGH FOR RIJS TO
DEVELOP THAT COULD RESULT IN A FEW BOWING SEGMENTS WITH A CONGEALED
STORM CLUSTER PROVIDING ENHANCED WINDS. EVEN IF THIS MOVES
NORTHEASTWARD WHERE CAPPING IS STRONGER, ANYTHING COMING OUT OF
KANSAS CAN REMAIN STRONG, AS ELEVATED PARCELS MAY REALIZE AS MUCH AS
2000 J/KG MUCAPE ABOVE A STABLE LAYER. IT IS IMPORTANT TO AT LEAST
ACKNOWLEDGE THAT THE LOW-LEVEL DIRECTIONAL WIND SHEAR DOES INCREASE
AS THE SURFACE CYCLONE MATURES ACROSS MOST OF THE LOWER MISSOURI
RIVER VALLEY, WITH RATHER IMPRESSIVE CYCLONIC CURVATURE. AS A
RESULT, THE LOW-LEVEL SRH VALUES ARE VERY HIGH. IF CURRENT MODEL
GUIDANCE IS OVERDOING THE STRENGTH OF THE CAP AND WE MANAGE TO
INITIATE A SURFACE-BASED STORM, COULD PRESENT A TORNADO THREAT.
HOWEVER, THIS IS HIGHLY CONDITIONAL, AND GIVEN THE STRENGTH OF THE
CAP, AT LEAST FOR RIGHT NOW APPEARS TO BE VERY DIFFICULT TO BE
ACHIEVED. WE WILL NEED TO MONITOR 0-3KM MLCAPE TRENDS AND 0-3KM BULK
SHEAR VECTOR ORIENTATION IF ANY ORGANIZED LINEAR SEGMENTS
DEVELOPMENT FOR MESOVORTEX GENERATION, BUT THE CURRENT GUIDANCE IS
NOT OVERLY EXCITED ABOUT THIS.
MONDAY MORNING, MAY SEE LINGERING THUNDERSTORM AND REMNANTS OF
SUNDAY NIGHT ACTIVITY SOMEWHERE OVER CENTRAL MISSOURI. POSSIBLE FOR
SEVERE HAZARDS TO STILL BE PRESENT, BUT EVENTUALLY WOULD THINK
STORMS WOULD MOVE ACROSS THE WARM FRONT INTO A MORE STABLE AIRMASS.
ATTENTION THEN TURNS TO MONDAY AFTERNOON. THE H5 TROUGH BEGINS TO
CLOSE-OFF AS A STRONGER VORTICITY MAXIMA WRAPS INTO THE BLACK HILLS
REGION. HOWEVER, A SECOND VORT MAX QUICKLY EJECTS OUT OF THE
INTERMOUNTAIN WEST TO THE SOUTH SIDE OF THE CLOSED PORTION OF THE
WAVE, AND MAINTAINS A STRONG JET STREAK ACROSS MOST OF THE CENTRAL
PLAINS. ADDITIONAL DCVA PHASES WELL WITH THE SURFACE CYCLONE AND WE
SHOULD CONTINUE TO SEE THIS DEEPEN THROUGH MONDAY MORNING. AS A
RESULT, SOUTHERLY TO SOUTHWESTERLY FLOW CONTINUES, MAINTAINING
STRONG THETA-E TRANSPORT INTO THE LOWER MISSOURI RIVER VALLEY AND
FORCES WARM FRONT NORTH OF INTERSTATE 70. SYNOPTIC SCALE
DETERMINISTIC GUIDANCE BRINGS THE WARM FRONT AS FAR NORTHWARD AS THE
IOWA-MISSOURI STATE LINE. HOWEVER, INITIAL RUNS OF THE CAMS
OVERNIGHT SO FAR HAVE NOT BEEN SURGING THE WARM FRONT MUCH FURTHER
NORTH OF U.S. HWY. 36. THE IMPLICATION OF THE WARM FRONT POSITIONING
IS HOW EXPANSIVE THE OPEN WARM-SECTOR ACROSS OUR FORECAST AREA
MONDAY AFTERNOON BECOMES. MLCAPE VALUES ABOVE 3000 J/KG ARE FAVORED
TO BE ACHIEVED, AND 00Z HREF MEAN SBCAPE VALUES SHOW A POCKET ABOVE
3000 J/KG. THE ONE FACTOR THAT CAN HINDER THIS IS IF THERE
CONVECTIVE DEBRIS LEFTOVER FROM SUNDAY NIGHT'S ACTIVITY. NARROW
CORRIDOR OF SURFACE TROUGHING AND SURFACE PRESSURE FALLS WITH
MATURING CYCLONE APPEARS TO BE ACCOMPANYING THE WARM FRONT WITH THIS
SYSTEM, WHICH WILL PROVIDE A FOCUS POINT FOR ENHANCED LOW-LEVEL WIND
SHEAR. ACROSS THE OPEN WARM SECTOR THOUGH, CURRENT GUIDANCE DEPICTS
THE NOSE OF THE H5 JET STREAK DISPLACED FURTHER WEST OVER CENTRAL
KANSAS, WHICH MAY ACTUALLY LIMIT SOME OF THE DEEP LAYER SHEAR FOR
THE AMBIENT WARM-SECTOR (AND MAY ALSO PREVENT ANY LIFT ACROSS THE
WARM SECTOR, KEEPING ALL ACTION ALONG THE WARM FRONT IN THE
AFTERNOON). CURRENT HRRR AND RAP SOUNDINGS DEEPER INTO THE WARM
SECTOR AWAY FROM THE WARM FRONT ACTUALLY SHOW A DRASTIC VEER-BACK
PROFILE THAT STARTS JUST ABOVE 2KM, WHICH MAY HURT DISCRETE
CONVECTION THAT COULD TRY TO DEVELOP ACROSS THE OPEN WARM-SECTOR IF
SOME LIFTING MECHANISM WERE TO BECOME AVAILABLE. THEREFORE, DURING
THE AFTERNOON AS PEAK HEATING OCCURS, THINKING THAT THE WARM FRONT
WILL BE THE MAIN FOCUS FOR STRONGER CONVECTION WHERE THE SHEAR
SHOULD BE SUPPORTIVE OF DISCRETE CELLS TAKING ON A SUPERCELLULAR
MODE. ALONG THE WARM FRONT, DISCRETE STORMS WILL POSE ALL HAZARDS
FROM DAMAGING WIND GUSTS, LARGE HAIL, AND TORNADIC POTENTIAL IF THE
LOW-LEVEL SHEAR PANS OUT AND IF FAVORABLE STREAMWISE VORTICITY CAN
BE INGESTED. NOT SURE HOW FAR AWAY FROM THE WARM FRONT THOUGH A
STORM CAN BE TO MAINTAIN THE TORNADIC POTENTIAL. THE DRYLINE FROM
SUNDAY LIKELY WILL NOT BE AS PRONOUNCED, AS PREVIOUS CONVECTION
SHOULD ADD MORE MOISTURE AND THE SUSPENSION OF MIXING OVERNIGHT
HALTS ITS PROGRESS, THOUGH REDEVELOPMENT OF DRYLINE MAY OCCUR OVER
CENTRAL KANSAS BEFORE THE COLD FRONT SWEEPS ACROSS. HEAVY RAIN FALL
COULD OCCUR IN THE AFTERNOON ESPECIALLY ALONG THE WARM FRONT WHERE
FORCING MAY BE THE STRONGEST. IF THE SYSTEM STALLS AND CAUSES THE
WARM FRONT TO REMAIN STATIONARY FOR FEW HOURS, THIS COULD INCREASE
RAIN EFFICIENCY. A WILD CARD FACTOR FOR MONDAY WILL BE IF THERE IS
AN OUTFLOW BOUNDARY FROM SUNDAY ACTIVITY THAT BECOMES ANOTHER FOCUS
POINT FOR EITHER CONVERGENCE AS A RESULT OF STRONGER DIFFERENTIAL
HEATING, OR LOCALIZED EFFECTS OF ALTERING THE SHEAR ENVIRONMENT. IF
THERE IS REMNANT OUTFLOW BOUNDARY SITTING SOMEWHERE IN THE OPEN WARM-
SECTOR, THEN CONVECTION HERE MAY HAVE A DIFFERENT BEHAVIOR. THEN
HEATING INTO THE LATE AFTERNOON, MID-LEVELS MAY START TO COOL AS THE
SECONDARY MID-LEVEL TROUGH AXIS MOVES THROUGH, PROVIDING BETTER
INSTABILITY. COLD FRONT TRAILING THE SURFACE CYCLONE ACROSS KANSAS
SHOULD APPROACH THE AREA AND INCREASE LOW-LEVEL CONVERGENCE ACROSS
THE FORECAST AREA, RESULTING IN ANOTHER INITIATION POINT LATE
AFTERNOON AND INTO THE EVENING (WE WILL SEE IF WE GET ANOTHER
DRYLINE DEVELOPMENT IN KANSAS THAT MIXES EASTWARD, AND HOW QUICKLY
THE COLD FRONT CATCHES UP TO IT). STILL LOOKING AT THE POSSIBILITY
FOR A NARROW WINDOW OF DEEP LAYER SHEAR VECTOR ORIENTATION
PERPENDICULAR TO THIS FRONT, WHICH COULD KICK-OFF A DISCRETE
CONVECTION. THERE MAY BE ENOUGH DEEP LAYER SHEAR FOR THIS TO BE
SUPERCELLULAR AS WELL, THOUGH IF IT MOVES QUICKLY OFF THE COLD
FRONT, MAY NOT STAY ORGANIZED INTO THE AMBIENT WARM SECTOR.
EVENTUALLY THE COLD FRONT SURGES AND THE DEEP LAYER SHEAR ORIENTS
MORE PARALLEL TO THIS BOUNDARY FORCING NEW UPDRAFTS TO CONGEAL,
AUGMENTED BY ANY LLJ DEVELOPMENT. BY THE EVENING HOURS, WOULD EXPECT
AN MCS TO DEVELOP, PERHAPS A LINEAR MODE RESULTING IN A WIND THREAT
AS IT MOVES ACROSS THE AREA. LARGE HAIL STILL CAN OCCUR WITH
STRONGER UPDRAFTS ALONG THE FRONT. ADDITIONAL RAINFALL MAY ALSO
INCREASE FLOODING CONCERNS, ESPECIALLY IF WE SEE ANY KIND OF STORM
TRAINING. ACTIVITY CONTINUES INTO THE OVERNIGHT HOURS, AND MAY STILL
PRESENT A SEVERE THREAT IF IT DOES NOT QUICKLY BECOME OUTFLOW
DOMINANT.
TUESDAY, REMNANTS OF A CONVECTIVE SYSTEM MAY STILL BE ONGOING FROM
AREAS ALONG HWY. 65 AND EASTWARD, AND COLD FRONT LIKELY SHOULD BE
NEAR THE MO-KS STATELINE IF NOT ALREADY FURTHER EASTWARD. A FEW
STRONGER STORMS ARE STILL POSSIBLE IN OUR EAST, BUT WE CONTINUE TO
SEE BETTER PROBABILITIES FOR SEVERE WEATHER PARAMETERS IN EASTERN AND
SOUTHEASTERN MISSOURI HEADING INTO TUESDAY. WHILE WE MAY STILL HAVE
A LOT OF LIFT AROUND, BETTER THERMODYNAMICS CONTINUES TO SHIFT
EASTWARD. MAIN ISSUE ON TUESDAY MAY BE FLOODING, AS BY TUESDAY WE
COULD BE LOOKING AT A 3-DAY RAINFALL TOTAL BETWEEN 3 AND 4 INCHES.
GIVEN THAT THERE IS STILL UNCERTAINTY WITH THE WARM FRONT ON
MONDAY, HAVE HELD OFF ON FLOOD WATCH ISSUANCE AT THIS TIME. ONCE WE
WE SEE WHAT HAPPENS ON SUNDAY AND THE CONDITION OF SOIL MOISTURE, WE
SHOULD HAVE A BETTER IDEA ON HOW MONDAY AND TUESDAY ACTIVITY MAY
AUGMENT FLOODING CONCERNS. FOR THE REMAINDER OF THE FORECAST PERIOD,
MID-LEVEL FLOW WILL BE MAINLY NORTHWESTERLY, WHICH SHOULD PROVIDE
COOLER CONDITIONS. A FEW WEAK DISTURBANCES MAY BRING ADDITIONAL RAIN
CHANCES ACROSS OUR AREA.
AVIATION /12Z TAFS THROUGH 12Z MONDAY/
ISSUED AT 617 AM CDT SUN MAY 18 2025
A FEW CLOUDS AROUND THIS MORNING BUT CONDITIONS WILL REMAIN VFR.
WARM FRONT STARTS TO PUSH NORTHWARD, AND MAY SEE SOME ISOLATED
STORMS MOVE THROUGH WESTERN MISSOURI BETWEEN 21Z AND 23Z THIS
AFTERNOON INTO EVENING. STRONGER THUNDERSTORMS MOVE OUT OF
KANSAS LATE THIS EVENING AND OVERNIGHT. EXPECTING MVFR CEILINGS
AND GUSTY WINDS AS THESE MOVE THROUGH. ACTIVITY SHOULD END BY
THE MORNING, BUT ANOTHER ACTIVE DAY IS FORECAST ON MONDAY.
EAX WATCHES/WARNINGS/ADVISORIES
MO...NONE.
KS...NONE.
DISCUSSION...KRULL
AVIATION...KRULL
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