Area Forecast Discussion
Issued by NWS Aberdeen, SD

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000
FXUS63 KABR 061205 AAA
AFDABR

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE ABERDEEN SD
645 AM CDT WED MAY 6 2015

.UPDATE...
ISSUED AT 635 AM CDT WED MAY 6 2015

12Z AVIATION DISCUSSION UPDATED BELOW.

&&

.SHORT TERM...(TODAY THROUGH FRIDAY AFTERNOON)
ISSUED AT 345 AM CDT WED MAY 6 2015

THE FORECAST CONTINUES TO BE RATHER CONVOLUTED THANKS TO THE SLOW
MOVING/WEAKENING UPPER SYSTEM SUPPORTING SEVERAL WAVES OF GENERALLY
LIGHT PRECIPITATION NOW THROUGH THURSDAY. THE FIRST WAVE HAS PASSED
NORTH OF THE CWA BEFORE BECOMING BETTER ORGANIZED...WHILE THE NEXT
EPISODE OF ISENTROPIC FORCING IS NOW LIFTING INTO THE CWA FROM THE
SOUTH. UNFORTUNATELY UPSTREAM RADAR COVERAGE IS SPOTTY WITH LIGHT
RETURNS. SREF PROBABILITIES POINT TO QPF BETWEEN 0.05 TO 0.10
INCHES. PROFILES THIS AFTERNOON ARE MARGINALLY
UNSTABLE...PARTICULARLY IN THE EASTERN CWA WHERE MUCAPE VALUES TOP
1000 J/KG...HOWEVER UPPER LEVEL SUPPORT IS FOCUSED WEST RIVER. BEST
ISENTROPIC FORCING SHIFTS TOWARDS FSD CWA TONIGHT...SO HIGHEST POPS
MIGRATE INTO FAR EASTERN COUNTIES...WHILE THE REST OF THE CWA WILL
REMAIN UNDER A MOIST AIRMASS WITH LITTLE UPPER SUPPORT. THE SYSTEM
LIFTS NORTHEAST THURSDAY...WITH ONE FINAL PERIOD OF WEAK ISENTROPIC
FORCING DURING THE DAY. SREF PROBABILITIES SUPPORT GENERALLY LIGHT
QPF BOTH TONIGHT AND THURSDAY...SO THINKING MOST AREAS WILL ONLY
RECEIVE AROUND A QUARTER TO HALF AN INCH IN TOTAL WITH THIS
SYSTEM.

SURFACE HIGH PRESSURE NOSES INTO THE REGION FOR EARLY FRIDAY BUT
COLD ADVECTION GENERATING A LIGHT NORTHEAST BREEZE SHOULD KEEP
TEMPERATURES FROM BOTTOMING OUT.

.LONG TERM...(FRIDAY EVENING THROUGH TUESDAY)
ISSUED AT 345 AM CDT WED MAY 6 2015

THERE ARE NOW SOME DISAGREEMENTS IN THE LONG TERM FORECAST THAT
WOULD IMPACT THE COVERAGE AND AMOUNT OF PRECIPITATION ACROSS THE CWA
FROM SATURDAY AFTERNOON INTO MONDAY AFTERNOON. THE GFS WAS DIVERTING
IN ITS SURFACE LOW PRESSURE AREA TRACK SOLUTION FROM THE EC AND GEM
MODELS FROM SATURDAY NIGHT INTO MONDAY. ON SATURDAY EVENING...ALL
THREE MODELS SHOW A SURFACE LOW PRESSURE AREA IN SOUTHEAST COLORADO.
FROM HERE...THE EC AND GEM SHOW THE SURFACE LOW TRACKING NORTHEAST
WHILE THE GFS SHOWS IT TRACKING EAST NORTHEAST. THE TRACK DIFFERENCE
WOULD AFFECT THE NORTHWARD PUSH OF THE RAINFALL SHIELD INTO OUR
REGION. AT THIS TIME...ALL THREE MODELS SHOW OUR CWA RECIEVING SOME
RAINFALL WITH LESS NORTHWARD PUSH AND DURATION WITH THE GFS MODEL.
THEREFORE...STILL HAVE IN GOOD CHANCES OF RAINFALL FOR MAINLY
SATURDAY NIGHT INTO MONDAY MORNING. WITH THE EC TRACK...RAINFALL
COULD CONTINUE IN THE EAST INTO MONDAY AFTERNOON. SURFACE HIGH
PRESSURE WILL THEN BUILD IN FOR MONDAY NIGHT AND TUESDAY WITH
CLEARING SKIES. HIGHS WILL BE MOSTLY IN THE 50S AND LOWER 60S FOR
SATURDAY THROUGH MONDAY WITH 60S FOR TUESDAY.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 635 AM CDT WED MAY 6 2015

MAINLY MVFR CEILINGS WILL MOVE OVER ALL TERMINALS THROUGH TODAY
AND TONIGHT AS LOW LEVEL MOISTURE CONTINUES TO BE HIGH. AS LIFT
FROM THE UPPER LEVEL LOW PRESSURE TROUGH INCREASES THROUGH THE
DAY AND NIGHT...SO WILL THE COVERAGE OF SHOWERS. EXPECT ALL
LOCATIONS TO BE AFFECTED BY SHOWERS WITH MAYBE A THUNDERSTORM OR
TWO. VISIBILITIES SHOULD BE REDUCED TO 3 TO 5 MILES AT TIMES.

&&

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

$$

UPDATE...MOHR
SHORT TERM...CONNELLY
LONG TERM...MOHR
AVIATION...MOHR



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