Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 271609 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
1109 AM CDT MON JUL 27 2015

.UPDATE...
ISSUED AT 1051 AM CDT MON JUL 27 2015

MADE SOME FAIRLY SIGNIFICANT CHANGES TO THE FORECAST THIS
MORNING. FIRST...DROPPED TEMPERATURES THIS AFTERNOON...DIURNAL
TRENDS ARE SLOW AND POOR MIXING WILL LIMIT MAX T POTENTIAL TODAY.
THEN...BUMPED WINDS UP SLIGHTLY FROM WHAT WE HAD GOING...JUST
BELOW WIND ADVISORY CRITERIA FOR OUR WESTERN CWA.

STILL NOT COMPLETELY CERTAIN WHAT WILL HAPPEN WITH POPS
TODAY...HOWEVER...TRIED TO DEPICT ONLY A SLIGHT CHANCE OF ANY
CONVECTION AHEAD OF THE FRONT THIS AFTERNOON. THERE IS NO REAL
NOTABLE FORCING...AND BULK SHEAR REMAINS UNIMPRESSIVE AHEAD OF THE
FRONT. LOW LEVEL SHEAR IS IMPRESSIVE HOWEVER...SO CANNOT RULE OUT
AN ISOLATED SEVERE STORM ACROSS THE EASTERN CWA BEFORE 00Z...BUT
UNLIKELY. THEN SLOWED DOWN THE TIMING OF POPS MOVING IN FROM THE
WEST TONIGHT. ESTIMATED TIMING LOOKS LIKE BETWEEN 00Z-03Z FOR
AREAS ALONG AND WEST OF THE MISSOURI RIVER...THEN IN THE 06Z
TIMEFRAME AROUND THE JAMES RIVER VALLEY...AND AFTER 06Z FURTHER
EAST. INCREASING BULK SHEAR...AND CONTINUED INSTABILITY TONIGHT
WILL RESULT IN A CHANCE FOR SEVERE STORMS...AND PWATS REMAIN IN
THE 1 TO 1.75 INCH RANGE. THEREFORE ADDED SEVERE AND HEAVY RAIN
WORDING INTO THE FORECAST.

&&

.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 350 AM CDT MON JUL 27 2015

MAIN CHALLENGE IN THE FORECAST CENTERS AROUND THUNDERSTORM CHANCES
LATE THIS AFTERNOON AND TONIGHT. A FAIRLY STRONG LOW PRESSURE SYSTEM
WILL SIT OFF TO THE WEST OF THE REGION TODAY...USHERING WARM AND
MOIST AIR INTO THE CWA. HIGHS WILL REACH THE 90S ACROSS THE
AREA...WITH DEWPOINTS IN THE UPPER 60S TO LOWER 70S. THE FRONTAL
BOUNDARY ASSOCIATED WITH THE LOW WILL TRACK ACROSS THE AREA TONIGHT.
MLCAPE VALUES OF 2500-4000 J/KG...OR HIGHER IN SOME MODELS...ALONG
WITH A 40-60 KNOT LOW LEVEL JET WILL ACCOMPANY THE FRONT AS IT MOVES
THROUGH...WITH THE RESULT BEING STRONG TO SEVERE THUNDERSTORM
DEVELOPMENT. HINDERING FACTORS MAY BE A STRONG CAP...+13 TO +16
DEGREES...AND THE FACT THAT THE BEST SHEAR WILL BE DISPLACED TO THE
WEST OF THE OTHER FEATURES. WITH THAT BEING SAID...ANY STORMS THAT
ARE ABLE TO DEVELOP WILL LIKELY GO SEVERE...SO WILL STICK WITH HIGH
CHANCE TO LIKELY POPS ACROSS THE AREA AND WILL MENTION THE POTENTIAL
FOR SEVERE STORMS.

STRONG MIXING BEHIND THE SYSTEM WILL MAKE FOR A VERY WINDY DAY ON
TUESDAY...THEN HIGH PRESSURE SETTLES IN BRINGING DRY...COOLER AND
LESS HUMID CONDITIONS FOR THE MID PART OF THE WEEK. AFTER HIGHS IN
THE 90S TODAY...WILL SEE A RETURN TO MORE NORMAL TEMPERATURES WITH
HIGHS IN THE 80S TUESDAY AND WEDNESDAY.

.LONG TERM...(WEDNESDAY EVENING THROUGH SUNDAY)
ISSUED AT 350 AM CDT MON JUL 27 2015

GOOD AGREEMENT IN THE LONG TERM WITH ALL OF THE MODELS WITH THE
UPPER LEVEL FLOW EVOLVING OVER THE REGION. THE LONG TERM BEGINS WITH
A STRONG UPPER LEVEL LOW PRESSURE AREA IN SOUTHERN CANADA LIFTING
NORTHEAST AND SETTLING OVER THE HUDSON`S BAY AREA. THIS WILL REMAIN
OVER THE BAY THROUGH THE REST OF THE LONG TERM WHILE A LARGE UPPER
LEVEL HIGH PRESSURE AREA SETTLES OVER THE SOUTH CENTRAL/SOUTHWEST US
WITH RIDGING EXTENDING NORTH ALONG THE WEST COAST. THIS WILL PUT OUR
REGION IN PREVAILING WEST TO NORTHWEST FLOW ALOFT. THUS...THE LONG
TERM LOOKS TO BE MAINLY DRY WITH MOSTLY SUNNY SKIES ALONG WITH NEAR
NORMAL TEMPERATURES IN THE 80S TO LOWER 90S.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 704 AM CDT MON JUL 27 2015

SOME STORMS MAY AFFECT THE ATY AREA EARLY THIS MORNING.
OTHERWISE...MORE EXPANSIVE SHOWER AND STORM DEVELOPMENT IS EXPECTED
THIS AFTERNOON AND EVENING AS A STRONG UPPER LEVEL LOW PRESSURE
TROUGH APPROACHES FROM THE WEST. ALL LOCATIONS COULD BE AFFECTED AT
OR IN THE VICINITY WITH SOME SEVERE WEATHER POSSIBLE. STRONG SOUTH
TO SOUTHEAST WINDS ARE ALSO EXPECTED TO DEVELOP TODAY AT ALL
LOCATIONS IN THE 15 TO 30 KNOT RANGE. A STRONG COOL FRONT MOVING
THROUGH TONIGHT WILL BRING WINDS AROUND TO THE NORTHWEST AT 20 TO 35
KNOTS AT PIR AND MBG.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
&&

$$

UPDATE...SERR
SHORT TERM...PARKIN
LONG TERM...MOHR
AVIATION...MOHR


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