Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 200856
AFDABR

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE ABERDEEN SD
356 AM CDT MON APR 20 2015

.SHORT TERM...(TODAY THROUGH WEDNESDAY AFTERNOON)
ISSUED AT 353 AM CDT MON APR 20 2015

FIRE WEATHER CONDITIONS TODAY AND LOW TEMPERATURES WEDNESDAY
MORNING WILL BE THE FORECAST CONCERNS. SEE THE FIRE WEATHER
DISCUSSION FOR INFORMATION ABOUT THE RED FLAG WARNING.

NORTHERLY FLOW ALOFT AND A SURFACE HIGH PRESSURE WILL DOMINATE THE
SHORT TERM PORTION OF THE FORECAST. WHILE 925/850 MB TEMPS WILL
RANGE BETWEEN 1 TO 2 STANDARD DEVIATIONS BELOW NORMAL...HIGHS
SHOULD BE ABLE TO WARM INTO THE 50S FOR MOST LOCATIONS OVER THE
NEXT THREE DAYS THANKS TO A DRY AIR MASS. HOWEVER LOWS SHOULD FALL
SEVERAL DEGREES BELOW NORMAL TONIGHT AND TUESDAY NIGHT DUE TO THE
SAME DRY AIR MASS. THE 0Z ADJMAV GUIDANCE SUGGEST LOWS IN THE
LOWER 20S BY WEDNESDAY MORNING...INCLUDING A TIED RECORD LOW IN
ABERDEEN. USED A BLEND OF CONSMOS/BCCONSMOS FOR LOWS WEDNESDAY
MORNING AS THESE MODELS USUALLY VERIFY WELL FOR LIGHT WINDS/CLEAR
SKY NIGHTS.

STRONG NORTHWESTERLY WINDS ARE EXPECTED AGAIN TODAY ACROSS MOST OF
THE CWA. A FAIRLY TIGHT PRESSURE GRADIENT ALONG WITH SOME
INSTABILITY WILL RESULT IN SUSTAINED WINDS OF 25 TO 35 MPH WITH
GUSTS AROUND 45 MPH. THE STRONGEST WINDS TODAY WILL LIKELY OCCUR
ALONG AND EAST OF THE JAMES RIVER VALLEY. INSTABILITY SHOWERS ARE
STILL POSSIBLE OVER THE NORTHEASTERN PORTION OF THE CWA LATER THIS
AFTERNOON. THIS AREA WILL SEE HIGHER SURFACE DEW POINTS AND COLDER
AIR ALOFT WHICH COULD CREATE THE SHOWERS.

.LONG TERM...(WEDNESDAY EVENING THROUGH SUNDAY)
ISSUED AT 353 AM CDT MON APR 20 2015

THE START OF THE PERIOD IS HIGH CONFIDENCE NORTHWEST FLOW ALOFT
OVER THIS CWA...AND SURFACE HIGH PRESSURE NOSING DOWN OVER THE
REGION AND COOL/DRY WEATHER CONDITIONS. ALL THE MODELS MAINTAIN
THAT FORECAST.

POPS-WISE...IT`S WHAT TRANSPIRES BY DAY 6 AND BEYOND THAT LEAVES
MUCH TO BE DESIRED IN THE LONGER RANGE MODELS. THE PATTERN IS
COMPLEX ENOUGH WITH EL NINO-POWERED SUBTROPICAL JET ENERGY
ACTIVELY DRIVING WEATHER SYSTEMS ACROSS THE SOUTHERN/EASTERN HALF
OF THE CONUS. TOSS IN A BLOCKING PATTERN JUST FOR GOOD
MEASURE...AND THE LEVEL OF CONFIDENCE IN MODEL SOLUTIONS REALLY
DROPS OFF. CURRENTLY...THE MODELS ARE INFERRING THAT SOMETHING
LIKE A REX BLOCK PATTERN ALOFT /AS SEEN OCCURRING RIGHT NOW OFF
THE WEST COAST/ IS BEING MAINTAINED AND SLOWLY WORKING EASTWARD
ACROSS THE WESTERN CONUS INTO THURSDAY BEFORE BREAKING DOWN AS JET
ENERGY ALOFT CARVES OUT A WESTERN CONUS LONGWAVE TROF. THE BOTTOM
LINE IS IT DOES APPEAR AS THOUGH THERE MIGHT BE A COUPLE OF
CHANCES FOR PRECIPITATION OVER THIS AREA LATE IN THE PERIOD...BUT
CERTAINLY NOT FOR 84 HOURS STRAIGHT /FROM FRIDAY THROUGH MONDAY/
AS THE SUPERBLEND GUIDANCE SUGGESTS. S/W ENERGY OVER THE WESTERN
CONUS WILL EVENTUALLY WORK EASTWARD...ONE WAY OR ANOTHER. IT`S
JUST NOT CLEAR AS TO WHETHER THIS CWA TAKES A DIRECT /POPS/ HIT
FROM ONE OR MORE LOW PRESSURE SYSTEMS BETWEEN DAYS 5 AND 7.

TEMP-WISE...AVG TEMPERATURE WILL BE HOVERING RIGHT AROUND NORMAL
TO PERHAPS A FEW DEGREES BELOW NORMAL THROUGHOUT THE PERIOD.
MODELS HINT THAT A MINOR WARM UP MAY BE POSSIBLE OVER THE
WEEKEND...IF RETURN FLOW SOUTHERLY WINDS CAN GET GOING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z MONDAY NIGHT)
ISSUED AT 1242 AM CDT MON APR 20 2015

BKN-OVC VFR CAA MIXING LAYER CLOUDS WILL SLOWLY ADVECT EAST OF THE
REGION INTO MONDAY MORNING. OTHERWISE...EXPECT STRONG NORTHWEST
WINDS OF 20 TO 30 KNOTS WITH GUSTS TO 35 TO 40 KNOTS TO DEVELOP
MONDAY MORNING FOR ALL LOCATIONS WITH VFR CONDITIONS. THE WINDS
WILL FALL OFF QUICKLY IN THE EARLY EVENING HOURS.

&&

.FIRE WEATHER...
ISSUED AT 353 AM CDT MON APR 20 2015

A VERY DRY AIR MASS WILL FILTER INTO THE AREA TODAY WITH DEW
POINTS LIKELY FALLING INTO THE SINGLE DIGITS AND TEENS BY THIS
AFTERNOON. THE LOWEST VALUES WILL OCCUR BETWEEN THE MISSOURI AND
JAMES RIVER VALLEY. THIS DRY AIR MASS WILL LIKELY PRODUCE RH
VALUES BETWEEN 15 TO 20 PERCENT. RH VALUES OF 25 TO 35 PERCENT ARE
POSSIBLE OVER THE PRAIRIE COTEAU REGION. ALL LOCATIONS WILL SEE
INCREASING NORTHWESTERLY WINDS BY MID MORNING. SUSTAINED WIND OF
25 TO 35 MPH ARE LIKELY WITH GUSTS AROUND 45 MPH. THE STRONGEST
WINDS WILL OCCUR ALONG AND EAST OF THE JAMES RIVER VALLEY.

FIRE WEATHER WILL BE A CONCERN ON TUESDAY AS WELL. RH VALUES OF 20
TO 30 PERCENT WILL COMBINE WITH NORTHWESTERLY WINDS OF 15 TO 25
MPH TO PRODUCE VERY HIGH FIRE DANGER.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING FROM NOON CDT /11 AM MDT/ TODAY TO 8 PM CDT /7 PM
     MDT/ THIS EVENING FOR SDZ267>272.

     WIND ADVISORY FROM 11 AM CDT /10 AM MDT/ THIS MORNING TO 7 PM CDT
     /6 PM MDT/ THIS EVENING FOR SDZ003>011-015>023-034>037-051.

MN...WIND ADVISORY FROM 11 AM THIS MORNING TO 7 PM CDT THIS EVENING FOR
     MNZ039-046.

&&

$$

SHORT TERM...SD
LONG TERM...DORN
AVIATION...DORN
FIRE WEATHER...SD




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