FXUS63 KDDC 220934
AFDDDC
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DODGE CITY KS
334 AM CST TUE DEC 22 2009
.DISCUSSION...
DAYS 1-2...
THIS WINTER WX FORECAST IS FRAUGHT WITH CHALLENGES...TOO MANY TO
GET INTO TOO MUCH DETAIL ABOUT GIVEN TIME CONSTRAINTS. THE 00Z
SUITE OF MODELS HAVE CHANGED QUITE A BIT REGARDING THE
CYCLOGENESIS. H7-85 CYCLOGENESIS IN MOST OF THE MODELS ARE FARTHER
NORTHWEST INTO KANSAS...INSTEAD OF FARTHER SOUTH. THE H5 VORTICITY
PATTERN NOW RESEMBLES A STRUNG OUT CONFIGURATION WHICH REALLY DOES
NOT FAVOR EXPLOSIVE LOWER TROPOSPHERIC DEVELOPMENT...AT LEAST
UNTIL THIS STRUNG OUT VORTICITY PATTERN RE-ALIGNS ITSELF MORE
MERIODIONALLY. THIS WILL NOT HAPPEN UNTIL THE SYSTEM IS EITHER ON
TOP OF SOUTHWEST KANSAS OR JUST TO THE EAST...WHICH DOES NOT FAVOR
A SUBSTANTIAL AMOUNT OF PRECIPITATION ON THE BACKSIDE OF THE LOW
WHERE ALL THE WIND WILL BE. THIS WILL OCCUR TO THE NORTH OF THE
H5/7 LOW...WELL TO THE NORTH...INTO NEBRASKA. THAT SAID...THERE
WILL STILL BE A PROLONGED PERIOD OF WINTER PRECIPITATION...AND THE
THINKING NOW IS THAT A SWATH OF 3 TO 7 INCHES OF SNOW WILL OCCUR
ACROSS THE NORTHWESTERN THIRD OF THE DDC FA...MAINLY ALONG AND
WEST OF A HUGOTON TO GARDEN CITY TO NESS CITY TO ELLIS
LINE...THESE AREAS WILL MOST LIKELY REMAIN WEST OF THE STRUNG OUT
MID LEVEL VORTICITY TRACK WHERE MID LEVEL FRONTOGENESIS IS MOST
FOCUSED. IMMEDIATELY SOUTHEAST OF THIS LINE...MORE MIXED
PRECIPITATION IS EXPECTED NEAR THE H85 BAROCLINIC ZONE. AM AFRAID
THERE MAY BE A FAIR AMOUNT OF SLEET AND/OR FREEZING RAIN
ACCUMULATION ACROSS THE CENTRAL SECTIONS OF THE DDC FA LATE
TONIGHT INTO AT LEAST THE FIRST PART OF WEDNESDAY.
WHILE THE PROBABILITY OF BLIZZARD CONDITIONS ARE WANING A LITTLE
BIT GIVEN THE FARTHER NORTH CYCLOGENESIS WEDNESDAY NIGHT
THURSDAY...WILL KEEP THE BLIZZARD WATCH GOING GIVEN CONTINUED
UNCERTAINTY AND SYNOPTIC DETAIL VOLATILITY. IT SEEMS MORE LIKELY
THAT THE NORTHEASTERN CORNER OF THE DDC FA WOULD STAND THE BEST
CHANCE AT BLIZZARD CONDITIONS...WITH THE FAR SOUTHEAST DDC FA THE
LOWEST CHANCE. WILL LET THE DAY SHIFT RE-EVALUATE THE BLIZZARD
WATCH...AS WELL AS THE NEED FOR AN UPGRADE OF THE WINTER WX
ADVISORY TO A WARNING IF GREATER-THAN-SIX INCH AMOUNTS APPEAR MORE
LIKELY. I JUST DO NOT HAVE THE CONFIDENCE IN WIDESPREAD SIX INCH
PLUS AMOUNTS YET. -UMSCHEID
DAYS 3-7...
THE 22/00Z RUNS OF ALL THE MODELS (SAVE THE UKMET) NOW TAKE THE
H7-H5 LOW CENTER TRAJECTORY MUCH CLOSER TO SW KANSAS THU MORNING AND
TO SOMEWHERE INVOF KANSAS CITY BY FRIDAY MORNING. THINK THIS
SLIGHTLY FURTHER NORTH/WEST TRAJECTORY IS A RESULT OF A STRONGER
WAVE (CURRENTLY OVER NRN BC) DROPPING INTO THE NRN ROCKIES/PLAINS
JUST AS THE SRN SYSTEM BEGINS TO CLOSE OFF OVER THE CENTRAL PLAINS.
THE NRN ENERGY DRAWS THE PLAINS LOW IN A BIT. THIS IS A RELATIVELY
NEW IDEA BUT THE EC/GFS/GEM ALL DO THIS TO ONE DEGREE OR ANOTHER AND
WHILE THERE IS SOME SKEPTICISM, WE'VE GOT TO GIVE THE NEW RUNS MORE
CONSIDERATION AS WE GET CLOSER TO THE EVENT. EVEN THOUGH THIS SORT
OF TRACK FAVORS LESS SNOW OVER SW KANSAS, WINDS WILL STILL BE AN
ISSUE. THE EFFICACY OF THE BLIZZARD WATCH STILL BOILS DOWN TO HOW
MUCH SNOW WE GET WITH THE SYSTEM BECAUSE WIND ON THE BACKSIDE OF THE
SYSTEM DOESN'T APPEAR TO BE IN QUESTION. THE MODELS STILL HINT AT
MOISTURE WRAPPING AROUND THE SYSTEM BACK INTO SW KS THROUGH MUCH OF
THURSDAY AND WHILE MODEL QPFS FOR THU ARE NOT IMPRESSIVE ANY MORE,
EVEN LIGHTLY FALLING SNOW CAN RESTRICT VIS AND WHEN COMBINED WITH
SIGNIFICANT BLOWING SNOW, IT COULD STILL LIKELY BE QUITE HAZARDOUS.
THAT, AND THE PROXIMITY OF THE STORM MAKES FURTHER MODEL TRENDS BACK
TOWARD WORSE CONDS STILL POSSIBLE. CONSIDERING ALL THAT, WILL
CONTINUE WITH THE BLIZZARD WATCH INTO THU.
PRECIP WILL PROBABLY BE OUT OF HERE BY CHRISTMAS DAY BUT GUSTY WINDS
WILL CONTINUE TO PRODUCE AREAS OF BLOWING AND DRIFTING. WILL
GRADUALLY REDUCE POPS TOWARD ZERO ON FRI BUT KEEP SOME BLOWING SNOW
MENTIONED. PRECIP WILL NOT BE FORECAST FOR THE REST OF THE EXTENDED
AS SHORTWAVE RIDGING ALOFT DEVELOPS OVER THE PLAINS. ALL THE MODELS
KEEP COLD AIR LOCKED IN PLACE THROUGH THE WEEKEND SO WILL KEEP COLD
TEMP FORECAST GOING. HIGHS OVER THE WEEKEND COULD ACTUALLY BE QUITE
A BIT COLDER THAN WE HAVE DEPENDING ON SNOW COVER - THE EC KEEPS SFC
TEMPS QUITE COLD - BUT WILL SHOW SOME MODERATION OVER TIME. THE EC
THEN BRINGS ANOTHER WAVE OUT INTO THE PLAINS ON TUESDAY FOR THE NEXT
CHANCE OF PRECIP. BUT THIS IS OUT OF MY FORECAST PERIOD AND NOT YET
WELL SUPPORTED BY OTHER MODELS. -WRIGHT
&&
.AVIATION...
A COLD FRONT AND ASSOCIATED SHALLOW COLD AIR WITH LOW CLOUD DECK/IFR
CIGS IS CURRENTLY PRESSING SOUTHWARD THROUGH NEBRASKA. IT WILL REACH
KHYS BY 22/12Z AND KDDC BY APPROX 22/18Z. IT WILL TAKE LONGER TO BACK
UPSLOPE INTO KGCK BUT EXPECT IFR CIGS TO SET IN THERE BY 23/21Z.
HIGH CLOUD IS INCREASING, MAKING THE LOW CLOUD HARDER TO TRACK AND
MODELS SEEM TO BE SHOWING THE ARRIVAL OF IFR CIGS TOO LATE. THUS
THERE IS SOME UNCERTAINTY ABOUT THE EXACT ARRIVAL TIMES. INCREASED
UPSLOPE LOW LEVEL FLOW ALONG WITH MID LEVEL LIFT ASSOCIATED WITH A
STORM SYSTEM COMING OUT OF THE SOUTHWEST U.S. WILL PRODUCE A VARIETY
OF FROZEN PRECIPITATION (-FZDZ/SLEET/SN) OVERNIGHT TONIGHT AT ALL
TERMINALS, MOST LIKELY AFTER 23/06Z. ALTHOUGH OUTSIDE THE UPCOMING
TAF PERIOD, WED WILL BE DICEY AT ALL TERMINALS WITH OCNL MIXED FZ
PRECIP EVENTUALLY CHANGING OVER TO SNOW. -WRIGHT
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 27 32 24 / 10 80 90 90
GCK 40 26 31 20 / 10 90 100 90
EHA 46 27 31 20 / 10 90 100 90
LBL 45 27 32 23 / 10 80 90 90
HYS 35 25 30 18 / 10 90 100 100
P28 46 37 44 29 / 10 50 90 90
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 6 PM CST /5 PM MST/ THIS EVENING TO
6 PM CST /5 PM MST/ WEDNESDAY FOR KSZ030-031-043>046-061>066-
074>080-084>088.
BLIZZARD WATCH FROM WEDNESDAY EVENING THROUGH THURSDAY AFTERNOON
FOR KSZ030-031-043>046-061>066-074>081-084>090.
&&
$$
FN25/34/34
