Area Forecast Discussion
Issued by NWS Aberdeen, SD

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992
FXUS63 KABR 171752 AAC
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1252 PM CDT SUN MAY 17 2015

.UPDATE...
ISSUED AT 1133 AM CDT SUN MAY 17 2015

VERY WRAPPED UP SYSTEM OVER THE CWA THIS AM. PRECIPITATION HAS
PUSHED ALL THE WAY WEST OF ABERDEEN...WHILE THE WRAP AROUND IS
EAST ALMOST TO WATERTOWN. IN THIS DRY SLOT...THE ATMOSPHERE WILL
BE MARGINALLY UNSTABLE SO CAN EXPECT A FEW THUNDERSTORMS TO
DEVELOP...THOUGH SKINNY CAPE WILL REDUCE THE THREAT FOR SEVERE.

WITH PRESSURE RISES UPWARDS OF 12MB AND A SHARP TEMPERATURE
GRADIENT...WITH READINGS IN NORTH DAKOTA ALREADY INTO THE UPPER
30S...EXPECT A BIT STRONGER PUSH OF WINDS INITIALLY...AND THUS
EXPANDED WIND ADVISORY FOR REST OF THE CWA.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY AFTERNOON)
ISSUED AT 414 AM CDT SUN MAY 17 2015

RAINFALL IS BEGINNING TO SPREAD BACK INTO THE CWA AS THE MAIN UPPER
LOW ENERGY BEGINS MOVING INTO THE REGION. ARRIVAL IS ACTUALLY ABOUT
RIGHT ON TIME FROM WHAT HI RES MODELS HAD BEEN SHOWING LAST EVENING.
WILL CONTINUE TO SEE RAINFALL INCREASE IN AREAL COVERAGE AND
INTENSITY OVER THE NEXT SEVERAL HOURS. PRECIPITATION WILL THEN
REMAIN OVER THE REGION THROUGH MUCH OF THE DAY...ALTHOUGH THE FAR
WESTERN CWA MAY START TO DRY OUT LATER THIS AFTERNOON. THUNDERSTORM
POTENTIAL IS STILL THERE TOO...ALTHOUGH THREAT FOR SEVERE WEATHER
LOOKS TO BE ALONG THE EASTERN FRINGE OF THE CWA AND INTO MN. TRACK
OF THE SFC LOW TODAY IS ACROSS EASTERN SD/WESTERN MN AS IT DEEPENS
AND MOVES NORTHWARD. IF ANY STORMS GET GOING OVER THE VERY FAR
EASTERN CWA...AN ISOLATED TORNADO THREAT WILL EXIST GIVEN THE
SURFACE VORTICITY AND LOW LEVEL SHEAR PRESENT.

AS THE LOW MOVES NORTH OF THE REGION LATE THIS AFTERNOON AND
EVENING...FOCUS WILL THEN SHIFT TO THE STRONG NORTHWEST WINDS
DEVELOPING ON ITS BACK SIDE AND THE COLDER AIR MOVING IN. IN
FACT...STRONG COLD AIR ADVECTION THIS AFTERNOON WILL BRING FALLING
TEMPERATURES FOR MUCH OF THE CWA...ESPECIALLY ALONG AND WEST OF THE
JAMES VALLEY. BUFKIT SOUNDINGS SHOW PRETTY HEFTY WINDS LATE THIS
AFTERNOON INTO THE EVENING AS STEEPER LOW LEVEL LAPSE RATES DEVELOP.
850 MB WINDS ARE ON THE ORDER OF 40 TO 50 KNOTS. RIGHT NOW IT
APPEARS THE BEST POTENTIAL FOR WIND ADVISORY SPEEDS WILL BE ACROSS
THE NORTHERN CWA AND ESPECIALLY INTO THE HIGHER ELEVATION COTEAU
REGION OF NORTHEAST SD. HAVE ISSUED A WIND ADVISORY FROM LATE THIS
AFTERNOON/EVENING INTO THE OVERNIGHT HOURS. DAY SHIFT MAY HAVE TO
ADJUST TIMING A BIT AND WATCH IF POTENTIAL EXISTS FOR ADDITIONAL
COUNTIES. MUCH COLDER AIR ALSO MOVES IN TONIGHT AND THERMAL PROFILES
SUPPORT A RAIN/SNOW MIX OR EVEN ALL SNOW LATE TONIGHT FOR THE FAR
NORTHERN CWA. DO NOT EXPECT MUCH IN THE WAY OF ACCUMS BUT
NONETHELESS...SNOW THIS LATE IN MAY IS RATHER RARE.

ONCE THIS STORM SYSTEM IS HISTORY...WILL THEN BE WATCHING THE COOL
CANADIAN HIGH PRESSURE BUILDING SOUTH OVER THE DAKOTAS MONDAY INTO
MONDAY NIGHT. IT WILL BE BRINGING WITH IT SOME RATHER COLD
TEMPERATURES AND EXPECTING LOWS BY SUNRISE TUESDAY TO BE NEAR OR
BELOW FREEZING FOR MUCH OF THE CWA. HAVE INCLUDED FROST MENTION IN
THE FORECAST. WILL HAVE TO CLOSELY WATCH THE PRESSURE GRADIENT TO
SEE IF WIND SPEEDS STAY UP ENOUGH THROUGH 12Z TUESDAY TO PREVENT A
TOTAL FREE FALL IN TEMPS. AND ONCE AGAIN...THE WET GROUND MAY KEEP
TEMPS UP A TAD. THAT SAID THOUGH...THE COLD AIR MASS ALONE LOOKS TO
BRING THE POTENTIAL FOR UPPER 20S/LOW 30S BY EARLY TUESDAY MORNING.

.LONG TERM...(TUESDAY EVENING THROUGH SATURDAY)
ISSUED AT 414 AM CDT SUN MAY 17 2015

THE EXTENDED PERIOD WILL START OFF WITH HIGH PRESSURE TO THE NORTH
OF THE REGION AND PRECIPITATION ASSOCIATED WITH LOW PRESSURE OVER
THE WESTERN HIGH PLAINS OCCURRING ACROSS PORTIONS OF WESTERN AND
SOUTHERN SOUTH DAKOTA. THE HIGH WILL SLOWLY DRIFT SOUTHWARD AND
LOOKS TO SETTLE IN OVER THE REGION WEDNESDAY NIGHT THROUGH EARLY
FRIDAY BEFORE GETTING PUSHED EASTWARD AHEAD OF A STRENGTHENING LOW
PRESSURE SYSTEM OVER COLORADO. THIS LOW WILL TRACK EASTWARD OVER THE
CENTRAL PLAINS OVER THE WEEKEND...BRINGING INCREASED PRECIPITATION
CHANCES.

TEMPERATURES WILL BE A BIT COOL TO START THE PERIOD UNDER THE
INFLUENCE OF THE SURFACE HIGH...WITH HIGHS MAINLY IN THE 50S ON
WEDNESDAY. WILL THEN SEE A RETURN TO NEAR NORMAL VALUES WITH HIGHS
IN THE 60S THURSDAY THROUGH SATURDAY. A COUPLE OF COOL NIGHTS OF
LOWS IN THE 30S TUESDAY NIGHT AND WEDNESDAY NIGHT...THEN A RETURN TO
OVERNIGHT LOWS IN THE 40S FOR THE REMAINDER OF THE PERIOD.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1252 PM CDT SUN MAY 17 2015

AT KABR AND KATY...EXPECT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS /PERHAPS EVEN A FUNNEL CLOUD OR TWO/ TO CONTINUE
THROUGH LATE AFTERNOON BEFORE WINDS SWITCH TO THE NORTHWEST AND
BECOME RATHER STRONG. PREVAILING FLIGHT CAT OVER THE NEXT 24 HOURS
WILL BE MVFR...WITH BRIEF FLUCTUATIONS UP OR DOWN FROM THAT
THROUGH THE REST OF THIS AFTERNOON.

AT KPIR AND KMBG...THE WINDS ARE NORTHWEST AND STRONG AND WILL
REMAIN SO OVER THE NEXT 24 HOURS. RAIN...MODERATE AT TIMES...WILL
ALSO CONTINUE AT THESE TWO TERMINALS INTO THIS EVENING BEFORE
PRECIPITATION TAPERS OFF. PREVAILING FLIGHT CATEGORY OVER THESE
TWO TERMINALS WILL LIKELY BE FLUCTUATING BETWEEN VFR AND MVFR OVER
THE NEXT 24 HOURS.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...WIND ADVISORY UNTIL 1 AM CDT /MIDNIGHT MDT/ MONDAY FOR SDZ003>006-
     009-010-015>018-033>037-045-048-051.

     WIND ADVISORY FROM 7 PM THIS EVENING TO 4 AM CDT MONDAY FOR SDZ007-
     008-011-019>023.

MN...NONE.
&&

$$

UPDATE...CONNELLY
SHORT TERM...TMT
LONG TERM...PARKIN
AVIATION...DORN



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