Area Forecast Discussion
Issued by NWS Aberdeen, SD

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FXUS63 KABR 240158 AAB
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
858 PM CDT WED APR 23 2014

.UPDATE...
THERE IS A COLD FRONT MOVING THROUGH THE CWA. THE LATEST RAPID
REFRESH GUIDANCE SHOWS IT SLOWING SOME OVERNIGHT AS THE NEXT WAVE
OF LOW PRESSURE DEVELOPING OVER SRN NEBRASKA LIFTS NEWD ALONG THE
FRONT. THE RAPID REFRESH MODEL ALSO SUGGESTS PRECIPITATION WITH
THIS NEXT WAVE SHOULD LIFT UP TOWARD THE REGION TOWARD 12Z
FRIDAY...AND LIKELY MISS MOST OF THE FAR EASTERN ZONES WITH ANY
ADDITIONAL PRECIPITATION.

WHILE SKIES PARTIALLY CLEAR AND WINDS RELAX WITHIN/NEAR THE
SLOWING SURFACE TROF...WENT AHEAD AND TOSSED IN SOME AREAS OF FOG
MENTION TO COVER ANY SURFACE MOISTURE LEFT OVER FROM THE PERIODS
OF LIGHT RAIN EARLIER IN THE DAY.

SEE BELOW FOR AN UPDATED AVIATION FORECAST DISCUSSION.


&&
.PREVIOUS DISCUSSION...
.SHORT TERM...TONIGHT THROUGH FRIDAY NIGHT

COLD FRONT IS SLOWLY WORKING ITS WAY EAST ACROSS WESTERN SD AND IS
APPROACHING THE WESTERN FRINGE OF THE CWA. AHEAD OF THE
FRONT...STRONG SOUTHEAST WINDS CONTINUE...WELL INTO ADVISORY
LEVELS FOR MANY LOCATIONS. ALTHOUGH...AS PRESSURE GRADIENT RELAXES
A BIT WITH THE APPROACH OF THE SFC TROUGH...WE ARE SEEING A SUBTLE
AND SLOW DROP OFF IN SPEEDS OUT OF CRITERIA LEVELS FROM WEST TO
EAST. WILL LET THE JAMES VALLEY PORTION OF THE WIND ADVISORY
EXPIRE AT 21Z WITH THE REMAINING EASTERN AREA GOING UNTIL 00Z.
ASIDE FROM THE WIND...ALSO DEALING WITH SCT SHOWERS AHEAD OF THE
FRONT. AS WAS SUGGESTED BY THE HRRR AND OTHER HI RES MODELS...WE
ARE SEEING A BIT OF REDEVELOPMENT ALONG AND EAST OF THE MISSOURI
RIVER. SO...EXPECTING DECENT CHANCES FOR PRECIP YET THIS AFTERNOON
AND INTO THE EVENING HOURS BEFORE COLD FRONT SCOURS OUT MOST OF
THE AVAILABLE MOISTURE.

NEXT AREA OF CONCERN IS THE CRITICAL FIRE DANGER ON THURSDAY.
BEHIND THE COLD FRONT...DRY AIR MOVES BACK INTO THE REGION ALONG
WITH BREEZY NORTHWEST WINDS GUSTING OVER 30 MPH. MIN RH VALUES ARE
EXPECTED TO FALL CLOSE TO 20 PERCENT IN THE JAMES VALLEY WITH
VALUES LIKELY GOING BELOW 20 PERCENT ACROSS CENTRAL/SOUTH CENTRAL
SD. HAVE THEREFORE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG
WARNING EFFECTIVE FROM 18Z TO 00Z TOMORROW.

TEMPS STAY MILD THROUGH THE SHORT TERM...AND THERE HAS BEEN AN
UPWARD TREND IN TEMPS ON FRIDAY. GFS IS STILL STUBBORN IN BRINGING
COOLER TEMPS AT 850 MB INTO THE NORTHERN/EASTERN CWA DURING THE
DAY FRIDAY...SHOWING A BIT MORE INFLUENCE OF THE COOLER HIGH TO THE
NORTH. THIS REALLY IS NOT SUPPORTED BY OTHER MODELS THOUGH SO HAVE
GONE WITH THE WARMER SOLUTIONS SEEN IN THE EC AND GEM.


.LONG TERM...SATURDAY THROUGH WEDNESDAY
THE MODELS SHOW GOOD AGREEMENT IN THE LONG TERM WITH A MAINLY WET
AND COOL PATTERN FROM SATURDAY THROUGH MONDAY NIGHT. THE MODELS
SHOW A SURFACE LOW PRESSURE AREA INTENSIFYING IN EASTERN COLORADO
THROUGH SATURDAY AFTERNOON. THIS SURFACE LOW PRESSURE AREA THEN
WOBBLES AND MOVES SLOWLY EAST AND SOUTHEAST ACROSS THE CENTRAL
PLAINS THROUGH MONDAY NIGHT. DEEP AND MOIST EAST TO SOUTHEAST FLOW
NORTH OF THE LOW PRESSURE AREA WILL BRING MAINLY RAIN TO MUCH OF
OUR CWA STARTING SATURDAY AFTERNOON. THE CHANCES OF RAIN CONTINUE
TO BE GOOD THROUGH MONDAY NIGHT. IT LOOKS LIKE MUCH OF THE CWA
WILL GET SOME DECENT RAINFALL ACCUMULATIONS WITH THIS SYSTEM.
OTHERWISE...THE SYSTEM WILL SLOWLY PUSH OUT FOR TUESDAY AND
WEDNESDAY WITH COOL CANADIAN SURFACE HIGH PRESSURE BUILDING IN.
WITH THE RAIN...CLOUDS AND CANADIAN AIR TEMPERATURES WILL BE MUCH
BELOW NORMAL THROUGH THE ENTIRE LONG TERM. HIGHS WILL BE MOSTLY
IN THE 40S AND 50S THROUGH THE PERIOD.


&&

.AVIATION...
00Z TAFS FOR THE KABR...KATY...KPIR AND KMBG TERMINALS

PRECIPITATION CHANCES ARE BASICALLY DONE AT KPIR/KMBG AND KABR.
HOWEVER...LATER TONIGHT INTO EARLY THURSDAY MORNING...ANOTHER
PIECE OF LOW PRESSURE ENERGY COULD POTENTIALLY GENERATE SOME LIGHT
PRECIPITATION AT THE KATY TERMINAL.

MEANWHILE...WEST OF THE COLD FRONT /KPIR AND KMBG/ THAT IS SLOWING
DOWN RIGHT NOW...VFR CONDITIONS SHOULD PREVAIL OVER THE NEXT 24
HOURS. EAST OF THE COLD FRONT KABR AND KATY...BUT ESPECIALLY
KATY...WILL SEE VFR CONDITIONS DETERIORATE INTO MVFR AND POSSIBLY
IFR STRATUS AND FOG FROM LATE THIS EVENING THROUGH LATE THURSDAY
MORNING. EVENTUALLY...THE COLD FRONT WILL PUSH EAST OF KABR AND
KATY DRYING THINGS OUT AS BREEZY WEST-NORTHWEST WINDS DEVELOP.


&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...RED FLAG WARNING FROM 1 PM CDT /NOON MDT/ TO 7 PM CDT /6 PM MDT/
     THURSDAY FOR LOWER BAD RIVER-MISSOURI COTEAU-UPPER CHEYENNE-
     UPPER JAMES RIVER-UPPER MISSOURI COTEAU.

MN...NONE.
&&

$$
UPDATE...DORN
SHORT TERM...TMT
LONG TERM...MOHR
AVIATION...DORN

WEATHER.GOV/ABERDEEN





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