FXUS63 KBIS 020920
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
320 AM CST WED DEC 2 2009
.SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
SIGNIFICANT COLD UPPER LEVEL LOW WILL BE THE MAIN WEATHER FEATURE IN
THE SHORT TERM...PROVIDING A SOURCE OF COLD AIR...CLOUDS AND LIGHT
SNOW. MODELS IN GOOD AGREEMENT AND USED A BLEND FOR DETAILS.
THIS UPPER LEVEL LOW CENTER WAS MOVING INTO NORTH DAKOTA FROM CANADA
THIS MORNING. ANOTHER UPPER LEVEL LOW CENTER WAS OVER HUDSON BAY.
THESE 2 LOWS ARE FORECAST BY THE MODELS TO ROTATE AROUND IN A
CYCLONIC FASHION INTO AN EXPANSIVE UPPER LOW WHICH WILL ACT TO
CONTINUE TO SEND ARCTIC AIR SOUTHWARD INTO NORTH DAKOTA THROUGH THE
SHORT TERM FORECAST AND INTO THE LONG TERM.
A SERIES OF UPPER LEVEL VORT ENERGY IMPULSES IS FORECAST TO MOVE
THROUGH THIS NORTHERLY FLOW ALOFT THROUGHOUT THE SHORT TERM. THE
STRONGER IMPULSES ARE PROGGED TO MOVE ACROSS NORTH DAKOTA TODAY AND
TONIGHT...WITH WEAKER IMPULSES FORECAST FOR FRIDAY AND SATURDAY.
THESE IMPULSES WILL PROVIDE UPPER LEVEL SUPPORT FOR SNOW SHOWERS.
PLENTY OF LOW LEVEL AND MID LEVEL MOISTURE WILL BE FOUND BENEATH THE
MASSIVE UPPER LOW FEATURE.
THIS TRANSLATES INTO A CHANCE OF SNOW SHOWERS TODAY AND
THURSDAY...WITH DIMINISHING CHANCES ON FRIDAY AS THE UPPER LEVEL
IMPULSES EMBEDDED IN THE FLOW ARE WEAK.
A SIGNIFICANT FEATURE SEEN THIS MORNING ON REGIONAL RADARS IS
APPARENT LAKE EFFECT SNOW SHOWERS FORMING OVER THE VAN HOOK ARM AND
THE SOUTHEASTERN HALF OF LAKE SAKAKAWEA. THE SHOWERS EXTENDED FROM
NEAR NEW TOWN SOUTHEASTWARD THROUGH HAZEN AND STANTON TO
WASHBURN...TO THE BISMARCK AND MANDAN AREA...AND SOUTH/SOUTHEAST
INTO SIOUX AND EMMONS COUNTIES. EXPECTING PERSISTENT NORTHWEST/NORTH
WINDS TODAY AND SEE NO REASON FOR THE LAKE EFFECT SHOWERS TO
DIMINISH...ESPECIALLY SINCE A SIGNIFICANT UPPER LEVEL VORT IMPULSE
MOVES SOUTHWARD ACROSS THE STATE. HENCE HAVE RAISED THE CHANCE OF
LIGHT SNOW TO 60 PERCENT (LIKELY CATEGORY) FOR TODAY FROM THE LAKE
AND SOUTHEASTWARD IN THE AFOREMENTIONED TOWNS/COUNTIES. MAY SEE SOME
ACCUMULATIONS VARYING FROM A DUSTING TO UP TO 2 INCHES IN SOME
LOCALES...ESPECIALLY THOSE AREAS ON OR NEAR BLUFFS AND CLOSER TO THE
LAKE.
REGARDING TEMPERATURES...A COOLING TREND THROUGH THE SHORT TERM.
EXPECT HIGHS TODAY IN THE 20S...WITH HIGHS 15 TO 25 THURSDAY AND
FRIDAY. LOWS TONIGHT 5 TO 15 ABOVE...AND SINGLE DIGITS THURSDAY
NIGHT AND FRIDAY NIGHT.
.LONG TERM...SATURDAY THROUGH TUESDAY...
UPPER LEVEL TROUGHING WILL DOMINATE THE WEATHER PATTERN DURING THE
EXTENDED PERIOD. BELOW NORMAL TEMPERATURES WILL CONTINUE...WITH
HIGHS MAINLY IN THE TEENS AND 20S AND LOWS MAINLY IN THE SINGLE
DIGITS. HAVE TRENDED TEMPS DOWNWARD A FEW DEGREES ON SATURDAY AND
SUNDAY. BY TUESDAY...THE COLDEST AIRMASS OF THE SEASON APPEARS
POISED TO DIP INTO NORTH DAKOTA...AND ADDITIONAL DOWNWARD
ADJUSTMENTS IN TEMPERATURES MAY BE NEEDED OVER THE NEXT FEW DAYS.
THERE MAY BE A FEW PERIODS OF FLURRIES OR SCATTERED LIGHT SNOW
SHOWERS...BUT WILL HOLD OFF INTRODUCING ANY ADDITIONAL POPS ATTM.
&&
.AVIATION...
A SFC TROUGH WILL DROP SOUTH THROUGH THE STATE TODAY AND WILL
SUPPORT ADDITIONAL SNOW SHOWERS AND FLURRIES. NOT EXPECTING ANY
SIGNIFICANT REDUCTIONS IN VISIBILITY AT THIS TIME BELOW MVFR...BUT
WILL HAVE TO MONITOR NARROW SNOW BAND ENHANCED BY LAKE SAKAKAWEA
THAT HAS BEEN IMPACTING KBIS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...VINING
LONG TERM/AVIATION...KINNEY
