174
FXUS64 KAMA 170417
AFDAMA
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE AMARILLO TX
1017 PM CST SAT NOV 16 2024
..NEW AVIATION
KEY MESSAGES
ISSUED AT 406 AM CST SAT NOV 16 2024
WIDESPREAD RAIN AND EMBEDDED STORMS LATE SUNDAY THROUGH MONDAY
WITH SLIGHT RISK FOR FLOODING IN THE EASTERN PANHANDLES.
MUCH COLDER TEMPERATURES BEHIND A COLD FRONT ON TUESDAY WITH A
HARD FREEZE EXPECTED FOR PORTIONS OF THE AREA.
SHORT TERM
(THIS EVENING THROUGH SUNDAY NIGHT)
ISSUED AT 211 PM CST SAT NOV 16 2024
A WEAK FRONT WILL ARRIVE SUNDAY MORNING BEFORE STALLING NEAR OR
JUST SOUTH OF SOUTHERN TX PANHANDLE. A ROBUST AND WELL ADVERTISED
UPPER LEVEL LOW WILL DIP INTO NRN MEXICO BEFORE MAKING THE TURN TO
THE NORTHEAST THROUGH SUNDAY EVENING. RAIN CHANCES WILL INCREASE
FIRST ACROSS THE SE TX PANHANDLE FROM LATE MORNING THROUGH EARLY
AFTERNOON AS A WEAK LEAD WAVE TRAVERSE THE AREA. THAT SAID, THE
STRONGEST LIFT WITH THIS STORM SYSTEM WILL OCCUR BETWEEN 6 UTC AND
18 UTC ON MONDAY AS SEEN IN MODEL H7-H3 Q VECTOR CONVERGENCE (WHICH
IS IMPRESSIVE).
THERE IS A MARGINAL RISK FOR SEVERE THUNDERSTORMS THAT INCLUDES
THE FAR SE CORNER OF THE AREA TOMORROW, BUT AVAILABLE CAPE WILL
LIMIT IF NOT ELIMINATE THE THREAT, ESPECIALLY IF THE AREA REMAINS
NORTH OF THE WEAK FRONTAL BOUNDARY WHICH WOULD SUGGEST MIXING SVR
TSTM GUSTS TO THE SURFACE WOULD BE UNLIKELY. THIS MEANS THE
THREAT OF HEAVY RAINFALL OVER AREAS THAT HAVE SEEN QUIT A BIT OF
RAIN THE PAST FEW WEEKS IS THE GREATER THREAT FROM THESE STORMS
AND THE ERO INCLUDES THE SE AREA IN A SLIGHT RISK FOR FLOODING.
MOST OF THE RAINFALL WILL COME AS THE STORM SYSTEM APPROACHES AND
MOISTURE AND LIFT SPREAD ACROSS THE AREA. RAIN ON MONDAY WILL
BECOME MORE ASSOCIATED WITH LOW CENTER WRAP AROUND MOISTURE AND/OR
COLD CORE CONVECTION WITHIN H7 FRONTOGENESIS BANDS BEFORE THE END
OF THE EVENT. THIS IS SOMETHING WE USUALLY TALK ABOUT MORE WITH
SYSTEMS CAUSING SNOWFALL THIS TIME OF YEAR, BUT TEMPERATURES WILL
BE MUCH TOO WARM FOR SNOW AND IN FACT THE NAM3 IS SHOWING ENOUGH
CAPE FOR TSTMS IN/NEAR THE LOW CORE. RAIN/STORMS WILL END FROM SW
TO NE MONDAY AFTERNOON.
RAINFALL DISCUSSION...THERE ARE MINOR DEVIATIONS ON THE H5 CENTER
TRACK AND QUESTIONS REGARDING HOW LONG THE LOW WILL REMAIN CLOSED
WHICH WILL INFLUENCE WHERE HIGHEST RAINFALL TOTALS OCCUR WITH
THIS SYSTEM. WHILE THE OPERATIONAL GFS HAS SHOWN A SHIFT IN HIGHER
RAINFALL AMOUNTS TO THE EAST, IT SHOULD BE NOTED THAT THE LREF
MEAN QPF REALLY HAS NOT CHANGED MUCH THE PAST FEW DAYS. SOME 12Z
GUIDANCE (ALTHOUGH NOT THE GFS) ACTUALLY TRENDED A BIT BACK WEST
FROM PREVIOUS 00Z RUNS. ALSO, THE OPERATIONAL GFS HAS BEEN
SIGNIFICANTLY BELOW THE GFS ENSEMBLE MEAN AT LEAST NEAR AMARILLO.
THE MAIN FACTOR DRIVING DIFFERENCES IS THE TRACK OF THE UPPER LOW
AND HOW THAT INFLUENCES LIFT AND MOISTURE TRANSPORT. THE ECMWF
ENSEMBLES AND GEM ARE MAINTAINING A SLIGHTLY MORE NORTHERN TRACK
AND SHOW STRONG H7 MOISTURE/THETA-E ADVECTION ACROSS MUCH OF THE
AREA INITIALLY WHILE THE OPERATIONAL GFS FOCUSES THE BEST H7
THETA-E ADVECTION ACROSS THE EAST AND PRETTY QUICKLY SHUNTS IT
FURTHER EAST LIMITING RAINFALL. THIS DIFFERENCE IS MAKING AS MUCH
AS AN INCH DIFFERENCE IN RAINFALL TOTALS (AROUND 1 INCH IN AMA VS
AROUND 2 INCHES). LOOKING AT CLUSTERS IN DESI, THE OPERATIONAL GFS
IS INCLUDED IN A LOWER QPF CLUSTER THAT ONLY INCLUDES 21 PERCENT
OF THE TOTAL ENSEMBLE MEMBERSHIP. THE TWO HIGHER QPF CLUSTERS
INCLUDE 64 PERCENT OF THE OPS MODELS/ENSEMBLES. THE HIGHEST QPF
FORECAST TOTALS ARE EXPECTED TO BE ACROSS THE FAR EASTERN CWA
WHERE RAINFALL AVERAGES OF 2 TO 2.5 INCHES ARE FORECAST. THE
CURRENT PROBABILITY OF 2 INCHES OR MORE RAINFALL ACROSS THE
EASTERN PANHANDLES IS AROUND 60-70 PER THE NBM, BUT DROPS OFF TO
AROUND 20 PERCENT NEAR AMARILLO. GIVEN EVERYTHING, WE MAY OPT FOR
A FLOOD WATCH IN THE FAR EAST (COLLINGSWORTH AND WHEELER), BUT
WILL LET A FEW MORE MODEL RUNS COME IN BEFORE HOISTING A WATCH.
GITTINGER
LONG TERM
(MONDAY THROUGH NEXT FRIDAY)
ISSUED AT 211 PM CST SAT NOV 16 2024
MODELS ARE IN GOOD AGREEMENT THE STRONGEST COLD FRONT OF THE
SEASON WILL ARRIVE DURING THE DAY ON TUESDAY AND NBM IS
SHOWING A WIDESPREAD FREEZE WED AND THU MORNINGS WITH A HARD
FREEZE IN THE NW HALF OF THE AREA. THE OPERATIONAL MODELS HAVE
SEEMED TO COME INTO AGREEMENT ON A WEAKER AND MORE PROGRESSIVE
TROUGH AND WITH LIMITED MOISTURE IN THE WAKE OF THE SUN/MON SYSTEM
THIS SECOND TROUGH WOULD NOT BE STRONG ENOUGH TO GENERATE MUCH IF
ANY PRECIPITATION. THAT SAID, THE ENSEMBLES CONTINUE TO HAVE A
FEW MEMBERS WHICH DEVELOP THE TROUGH MUCH MORE JUST WEST BEFORE IT
PASSES THROUGH THE AREA AND WITH THE ASSOCIATED STRONGER LIFT,
THEY GENERATE SOME LIGHT SNOW ACROSS THE AREA EARLY WEDNESDAY.
LOOKING AT DESI CLUSTERS, THERE WERE FOUR GROUPS OF SOLUTIONS AND
CLUSTER 4 IS THE STRONGEST WITH THE SYSTEM AND IS THE ONLY ONE
THAT GENERATES SIGNIFICANT SNOWFALL ACROSS THE REGION. WITH THE
00Z MODELS, CLUSTER 4 INCLUDED 30% OF THE GEFS MEMBERS, 8% OF THE
ENS MEMBERS AND 10% OF THE GEPS MEMBERS. THE TREND HAS DEFINITELY
BEEN TOWARD THE DRIER SOLUTIONS AS OVER 50% OF THE TOTAL MEMBERS
FAVORED SOME LEVEL OF MEASURABLE SNOW IN AMARILLO ON THURSDAY'S
RUNS, BUT THAT DROPPED TO ONLY 15% WITH 00Z MODELS AND WAS ONLY
5% WITH THE 12Z RUNS. NOT SURPRISINGLY THE NBM POPS ARE ONLY
10-15% TUE NIGHT AND EARLY WED AS A RESULT. SO MEASURABLE SNOWFALL
WITH THE SECONDARY HAS BECOME VERY MUCH THE OUTLIER SOLUTION AT
THIS POINT, BUT STILL BEARS WATCHING.
OPERATIONAL MODELS AGREE IN EAST COAST TROUGHING AND BOARD WRN US
RIDGING LATE NEXT WEEK IN THE WAKE OF THE TUE/WED TROUGH. THE
VERY WEAK/FLATTENED RIDGE MAY DRIFT TO THE CENTRAL US BY THE
WEEKEND, WITH THE GEM BEING AN OUTLIER BY HOLDING THE RIDGE
FURTHER WEST. EITHER WAY, WEATHER PATTERN LOOKS QUIET THU-SAT AND
NBMS TEMPS RANGING FROM 30S TO LOW 60S ARE VERY CLOSE TO AVERAGE.
IF THE 00Z GEM VERIFIES, THERE WOULD BE ANOTHER COD FRONT PUSHING
INTO THE AREA ON SATURDAY AND CONFIDENCE IN THE SAT FORECAST
REMAINS ON THE LOW SIDE.
GITTINGER
AVIATION
(06Z TAFS)
ISSUED AT 1013 PM CST SAT NOV 16 2024
VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THIS FORECAST PERIOD
WITH WINDS AROUND 10 KTS OR LESS. PERIODS OF LIGHT SHOWERS ARE
EXPECTED AT DALHART AND AMARILLO TONIGHT AND PERHAPS LAST INTO THE
MORNING HOURS. LOWER CEILINGS WILL MOVE IN FROM THE SOUTH AND
IMPACT AMARILLO BEGINNING THIS EVENING AS VFR MOVES INTO MVFR AND
EVEN IFR. HAVE ALSO PUT IN A PROB30 FOR THUNDERSTORMS FOR
AMARILLO THIS EVENING.
PRELIMINARY POINT TEMPS/POPS
AMARILLO TX 46 65 45 55 / 10 40 100 70
BEAVER OK 41 63 44 53 / 20 10 90 80
BOISE CITY OK 35 54 38 53 / 10 10 80 50
BORGER TX 45 67 46 56 / 10 30 100 70
BOYS RANCH TX 45 64 45 59 / 20 30 90 70
CANYON TX 45 65 45 57 / 20 40 100 70
CLARENDON TX 49 64 48 57 / 10 60 100 70
DALHART TX 39 59 40 57 / 20 10 90 60
GUYMON OK 39 60 40 54 / 20 10 90 70
HEREFORD TX 45 64 45 59 / 20 50 100 70
LIPSCOMB TX 45 65 48 55 / 0 30 100 80
PAMPA TX 45 64 46 53 / 0 40 100 70
SHAMROCK TX 50 65 50 58 / 0 60 100 70
WELLINGTON TX 51 64 52 60 / 0 70 100 50
AMA WATCHES/WARNINGS/ADVISORIES
TX...NONE.
OK...NONE.
SHORT TERM...88
LONG TERM....88
AVIATION...52
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