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000
FXUS63 KFSD 102325
AFDFSD

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SIOUX FALLS SD
625 PM CDT THU APR 10 2014

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 338 PM CDT THU APR 10 2014

WEAK SHORT WAVE ACCOMPANIED BY MID LEVEL MOISTURE IS EXPECTED TO
BRING MINIMAL AND SPOTTY SHOWERS TO THE FORECAST AREA AS IT MOVES
THROUGH TONIGHT. WILL KEEP SOME POPS BARELY INTO THE CHANCE
CATEGORY NORTH...OTHERWISE SLIGHT CHANCE/ISOLATED SHOULD REPRESENT
COVERAGE OF ANY MEASURABLE PRECIPITATION...AND GIVEN THE DRY AIR
BELOW THE MID LEVELS...AM TEMPTED TO GO MAINLY SPRINKLES. THIS WEAK
SYSTEM SHOULD BE MOVING OUT OF THE AREA BY DAYBREAK AND WILL LINGER
A SLIGHT CHANCE FAR EAST FOR NOT VERY LONG FRIDAY MORNING. LITTLE
CHANGE IN PROJECTED LOW TEMPERATURES TONIGHT. THEY WILL REMAIN A BIT
ABOVE GUIDANCE WITH THE CLOUD COVER FOR MUCH OF THE NIGHT AND THE
FAIRLY QUICK TURN TO A LIGHT WARMING SOUTHWESTERLY FLOW. LINGERING
BRISK WINDS FAR EAST/NORTHEAST LATE THIS AFTERNOON WILL QUICKLY FADE
BY EARLY EVENING.

AS LINGERING CLOUDS PASS QUICKLY EAST OF THE AREA FRIDAY MORNING...A
BRIGHT AND GOOD HEATING DAY IS FORESEEN FOR THE AREA FOR FRIDAY.
WINDS WILL GO FROM SOUTHWESTERLY TO WESTERLY AND MODESTLY PICK UP.
HIGH TEMPERATURES WILL CONTINUE TO BE FORECAST ABOVE GUIDANCE WHICH
SEEMS TO LACK A LITTLE OF THE POWER OF THE SPRING SUNSHINE...AND
MOST HIGH READINGS SHOULD MAKE THE 70 TO 75 RANGE. SOME HIGH CLOUD
INCREASE LIKELY IN THE AFTERNOON...FOR THE TIME BEING I AM PLAYING
THIS TO TAKE A WHILE TO THICKEN UP...AND THERE SHOULD BE LITTLE
BLOCKING OF THE ABOVE MENTIONED SPRING SUNSHINE.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 338 PM CDT THU APR 10 2014

YET ANOTHER WEAK SHORT WAVE MOVES ACROSS OUR AREA FRIDAY NIGHT
THROUGH A ZONAL FLOW ALOFT. THE MAIN FEATURE WITH THIS WAVE IS THE
AMOUNT OF WARM AIR ADVECTION AND POSITIVE THETAE ADVECTION
ASSOCIATED WITH IT. HOWEVER WITH EACH PASSING MODEL RUN...THEY ARE
ALL SHOWING MORE AND MORE DRY AIR IN THE LOW LEVELS. FOR NOW...WE
ARE DEALING WITH A VERY DRY PROFILE BELOW 700MB. DO NOT BELIEVE
THERE WILL BE ENOUGH DYNAMICS WITH THIS WAVE TO OVERCOME THE DRY
LOW LEVELS...AS CAN BE THE CASE SOMETIMES WHEN THE WAVE IS
STRONGER. THEREFORE LOWERED POPS AND KEPT THEM EAST OF THE JAMES
RIVER VALLEY. WITH THE CLOUDS AND SOUTH TO SOUTHEAST SURFACE FLOW...
THE LOWS SHOULD BE MILD AND THEREFORE FOLLOWED THE WARM RAW
GUIDANCE VALUES. THE MOS TYPE VALUES AND CONSENSUS VALUES STILL
LOOK TOO COLD GIVEN THE 925MB TEMPERATURES.

ON SATURDAY...A WELL ADVERTISED UPPER TROUGH BEGINS TO DIG
SOUTHWARD ACROSS THE INTERMOUNTAIN WEST...EVENTUALLY ENDING UP IN
EASTERN IDAHO AND WESTERN WY BY 12Z SUNDAY. SATURDAY IS BEGINNING
TO LOOK MORE AND MORE UNEVENTFUL...AS IT DOES LOOK LIKE THE
SURFACE TO 850MB WIND SHIFT IS GOING TO SCREAM THROUGH OUR
FORECAST AREA IN FAIRLY SHORT ORDER...LIMITING OUR CHANCES FOR
CONVECTION EVEN IN OUR SOUTHEAST ZONES. THEREFORE IT CONTINUES TO
LOOK WARM ACROSS THE FORECAST AREA WITH WIDESPREAD 70S...AND WE
WILL HAVE TO MONITOR THE SIOUX CITY AREA TO WATCH IF THEY MAY GET
IN THE LOWER 80S.

NOW THE 12Z GFS/UKMET/GEM GLOBAL/NAM MODELS ARE ALL SHOWING A
DRAMATIC INCREASE IN MOISTURE FROM WEST TO EAST ACROSS OUR AREA
SATURDAY NIGHT...MAXIMIZING LATE SATURDAY NIGHT THROUGH MIDDAY
SUNDAY. THE ECMWF CONTINUES TO SHOW A MUCH WEAKER SOLUTION...IN
TAKING THE NORTHERN STREAM UPPER TROUGH AND CUTTING OFF OUR
MOISTURE IN A BIG WAY. SINCE THE MODELS ARE IN NO WAY LOCKED ONTO
THIS SYSTEM TO THE WEST...IN HOW FAR SOUTH IT WILL DIG AND HOW
LONG THE NORTHERN STREAM ENERGY WILL HOLD OFF OR NOT...DECIDED TO
KEEP THE HIGH POPS PRIMARILY FROM POINTS I 90 AND SOUTHWARD. IT
STANDS TO REASON THAT NO MATTER WHAT HAPPENS...THAT THE NORTHERN
TROUGH WILL CUTOFF OUR NORTHERN ZONES FIRST...THEN ADVECT THE DRY
AIR SOUTHWARD THROUGH THE DAY ON SUNDAY. AT ANY RATE...SUNDAY DOES
NOT LOOK LIKE A PLEASANT DAY...WITH WINDY CONDITIONS FROM THE
NORTH AND WHAT COULD BE A COLD RAIN...MIXED WITH SNOW IN OUR
NORTHERN ZONES. IT IS DISTURBING THAT THE 925MB TO 850MB
TEMPERATURES GO SUB ZERO BY EARLY SUNDAY WHICH ONE WOULD THINK
WOULD PRODUCE SNOW. BUT THE SURFACE TEMPERATURES STILL LOOK JUST A
TAD TOO WARM TO WARRANT SNOW EXCEPT IN OUR NORTH IF IT PRECIPITATES
THERE. CONCERNING TEMPERATURES...THEY LIKELY WILL NOT RISE MUCH
ON SUNDAY AFTER MORNING LOWS...WITH COLD AIR ADVECTION POURING IN
WHETHER IT PRECIPITATES OR NOT.

THE REST OF THE EXTENDED LOOKS ON THE COOL SIDE...AND WE WILL
MONITOR THE NEXT SYSTEM WHICH LOOKS TO AFFECT THIS AREA AT THE END
OF THE EXTENDED PERIOD BY WEDNESDAY NIGHT AND THURSDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z FRIDAY EVENING)
ISSUED AT 621 PM CDT THU APR 10 2014

VFR CONDITIONS ARE EXPECTED THROUGH THE TAF PERIOD. ISOLATED SHOWERS
WILL SPREAD WEST TO EAST ACROSS THE AREA THIS EVENING AND
TONIGHT...HOWEVER VFR CONDITIONS WILL PERSIST IN ANY SHOWERS.

&&

.FIRE WEATHER...

THE RED FLAG WARNING FOR SOUTHWEST MN WILL BE CONTINUED THROUGH 7 PM
CDT AS PLANNED. WINDS WILL BEGIN TO DROP OFF LATE THIS AFTERNOON.
BUT WITH SOME SPARE ROOM ON RED FLAG CONDITIONS...SLIGHTLY WINDIER
AND DRIER IN PART OF THE AREA THAN EARLIER FORECAST...THIS LATER
ENDING TIME THAT WE HAD IN YESTERDAYS FORECAST LOOKS GOOD. SMALL
PARTS OF NORTHWEST IOWA...DOWN TO THE SPENCER AREA...AND WEST FROM
MN TO BROOKINGS AND FSD...HAVE BEEN CLOSE TO RED FLAG CONDITIONS
BUT HAVE ELECTED NOT TO ADD THEIR FIRE WEATHER ZONES TO THE
WARNING WITH THE WINDS TABBED TO DROP OFF FASTER THAN YESTERDAY.

YET ANOTHER RED FLAG THREAT EXISTS FOR FRIDAY. THIS ONE IS OVER THE
AREA. WINDS ARE EXPECTED TO BE MORE GENERAL AND BELOW RED FLAG
LEVELS WITH HUMIDITIES DROPPING TO JUST BELOW 25 PERCENT. AM LEAVING
OUT AT THIS TIME WITH WINDS ALOFT PROJECTED TO PICK UP MORE
GRADUALLY WITH HEIGHT THAN WE HAVE BEEN SEEING...MAKING A JUMP TO
RED FLAG LEVEL WINDS LESS LIKELY...BUT THIS WILL HAVE TO BE REVIEWED.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...RED FLAG WARNING UNTIL 7 PM CDT THIS EVENING FOR MNZ900.

IA...NONE.
NE...NONE.
&&

$$

SHORT TERM...
LONG TERM...MJ
AVIATION...
FIRE WEATHER...