893
FXUS63 KABR 210710
AFDABR
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
210 AM CDT SAT SEP 21 2019
DISCUSSION (TODAY THROUGH SATURDAY)
ISSUED AT 209 AM CDT SAT SEP 21 2019
MAIN CHALLENGE THROUGH THE SHORT RANGE CENTERS AROUND TONIGHT. SFC
FRONT/DRY LINE WILL CONTINUE TO MOVE ONLY VERY SLOW THROUGH THE
AFTERNOON, BUT SHOULD PICK UP FORWARD MOMENTUM BY MID EVENING AS MID
LEVEL TROF STARTS LIFTING NORTHEAST OUT OF THE ROCKIES, AND INTO THE
NORTHERN PLAINS. A FEW CAMS STILL SHOW ISOLATED CONVECTION FORMING
OUT AHEAD OF THE FRONT THROUGH EARLY EVENING, SO WILL KEEP SLIGHT
CHC POPS GOING ACROSS THE REGION FOR THE LATE AFTERNOON/EARLY
EVENING. THAT SAID, THE LATEST HRRR RUNS HAVE BACKED OFF ON PRE-
FRONTAL CONVECTION TO SOME DEGREE. MORE WIDESPREAD CONVECTION
APPEARS POSSIBLE OVERNIGHT AS FRONT TRAVERSES THE FORECAST AREA. AN
UNSTABLE TO VERY UNSTABLE AIRMASS ACROSS THE AREA WOULD SUPPORT
SEVERE STORMS, HOWEVER, DEEP LAYER BULK SHEAR WILL BE LACKING, AND
SUGGESTS CELLS COULD FAVOR PULSE SEVERE. LARGE CAPE PROFILES WOULD
SUPPORT LARGE HAIL POTENTIAL WITH EARLY EVENING ACTIVITY. THE MAIN
THREAT FROM THE LATER ACTIVITY WILL PROBABLY BE STRONG WIND AS MID
LEVEL WINDS FROM APPROACHING TROF OVERSPREAD THE CWA, AND FORCE ANY
CELLS INTO LINE SEGMENTS. HEAVY RAIN REMAINS A THREAT GIVEN WAY
ABOVE NORMAL PWATS. WITH ONLY ISOLATED ACTIVITY ANTICIPATED EARLY,
AND PROGRESSIVE STORMS EXPECTED LATER IN THE EVENING, WILL HOLD OFF
ON ANY HYDRO HEADLINES AT THIS TIME.
BEHIND THE FRONT, CONDITIONS WILL TURN COOLER AND LESS HUMID FOR
SATURDAY/SATURDAY NIGHT. LINGERING SHOWERS ARE POSSIBLE SATURDAY IN
THE NORTH AND EAST. SATURDAY NIGHT SHOULD BE TRANQUIL AND COOL. DID
BEEF UP WINDS FROM BLENDED GUIDANCE GIVEN THE DEEP MIXING WITH
AFTERNOON HEATING. ALSO BOOSTED TEMPS A TOUCH BASED ON DEEP MIXING
OF A STILL WARM AIRMASS.
WHILE A FEW THUNDERSTORMS REMAIN EARLY THIS MORNING ACROSS OUR
WESTERN COUNTIES, THE MAIN THREAT IS TRANSITIONING TO MODERATE TO
HEAVY RAIN. AS OF 0630Z, RADAR ESTIMATED RAINFALL OF 1-2IN HAS FALLEN
OVER FAR WESTERN CORSON COUNTY. WE WILL CONTINUE TO MONITOR THE
TRENDS AND WILL ISSUE HYDRO PRODUCTS AS NEEDED. THE CURRENT SURFACE
ANALYSIS SHOWS THE SURFACE LOW SET UP NEAR MBG, WITH A COLD FRONT
STRETCHING SOUTH BETWEEN JONES AND LYMAN COUNTIES. THE ENTIRE SYSTEM
WILL CONTINUE TO SHIFT EAST-NORTHEAST, WITH THE COLD FRONT NEAR ABR
TO HON BY 12Z, AND THEN THE SD/MN BORDER BY 18Z SATURDAY.
PRECIPITATION WILL LINGER THROUGH THE MORNING. THE 500MB LOW/OPEN
WAVE CURRENTLY OVER CENTRAL MT/NORTHWESTERN WY WILL WILL BE TO OUR
WEST-NORTHWEST BY 18Z. WHILE A COUPLE OF RUMBLES OF THUNDER MAY BE
POSSIBLE THROUGH THE DAY TODAY, THE MOST LIKELY SCENARIO IS LIGHT
SHOWERS THROUGH THE AFTERNOON, WHEN THE SURFACE LOW EXITS INTO
ONTARIO AND THE 500MB LOW SHIFTS ACROSS NORTHERN ND. DRY AND COOLER
AIR WILL SETTLE IN FOR SUNDAY, WITH HIGHS NEAR 70 DEGREES.
A SLOW MOVING COLD FRONT WILL SLIDE ACROSS THE AREA MONDAY NIGHT
THROUGH THE DAY TUESDAY. MOST OF THE ENERGY WILL REMAIN WELL TO OUR
NORTH. SLIGHT CHANCE A SHOWERS WILL RETURN TUESDAY NIGHT THROUGH
WEDNESDAY, AS A BROAD 500MB TROUGH MOVES ACROSS THE NORTHERN TIER OF
THE COUNTRY. NEAR TO SLIGHTLY BELOW NORMAL TEMPERATURES SHOULD BE
THE RULE FOR WEDNESDAY THROUGH SATURDAY. THE CHANCE OF A MORE ROBUST
SYSTEM STILL LOOKS REASONABLE FOR THE END OF THE WORK WEEK INTO THE
WEEKEND, WITH THE POTENTIAL FOR MORE WIDESPREAD SHOWERS.
AVIATION
(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 1222 AM CDT SAT SEP 21 2019
SHOWERS AND STORMS WEST OF MBG AND PIR AT 0530Z WILL BE MOVING
ACROSS THOSE SITES SHORTLY AFTER 06Z. WHILE THERE COULD BE SHOWERS
AHEAD OF THE MAIN LINE, THE NORTHEASTWARD PROGRESSION OF STORMS
WOULD BRING THEM TO ABR BY AROUND 09Z, AND ATY BY AROUND 11Z. WITH
THE SURFACE LOW STILL NEARBY, A FEW SHOWERS WILL STILL BE
POSSIBLE THROUGH THE DAYTIME HOURS SUNDAY. WIND GUSTS WILL BE THE
MAIN CONCERN, GUSTING 20-30KTS THROUGH THE DAY.
ABR WATCHES/WARNINGS/ADVISORIES
SD...NONE.
MN...NONE.
DISCUSSION...KF
AVIATION...KF
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