000
FXUS63 KFGF 011615 AAA
AFDFGF

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE GRAND FORKS ND
1015 AM CST SUN DEC 1 2013

.UPDATE...
ISSUED AT 1015 AM CST SUN DEC 1 2013

CONCERNS THIS MORNING INCLUDE FOG AND LIGHT SNOW.

DENSE FOG DEVELOPED ACROSS AREAS WEST OF THE VALLEY FROM LANGDON
TO COOPERSTOWN TO GWINNER BETWEEN 7 AND 8 AM CST AND HAS
MAINTAINED ITSELF FOR MUCH OF THE MORNING. LATEST RAP/HRRR
GUIDANCE SUGGESTS POCKETS OF DENSE FOG WILL CONTINUE THROUGH LATE
MORNING AND INTO THE AFTERNOON AND WITH NO REAL CHANGE IN AIR MASS
AND/OR LOW LEVEL WIND FIELD...WILL ISSUE A DENSE FOG ADVISORY FOR
WESTERN TIER COUNTIES UNTIL 21 UTC. MAY VERY WELL BE ABLE TO
CANCEL IT EARLY...BUT VISIBILITIES AT OR BELOW 1/4 SM ARE
WIDESPREAD ENOUGH TO WARRANT ISSUANCE.

ALSO INCREASED POPS A BIT FARTHER EAST ACROSS EASTERN ND THROUGH
THE DAY WITH A NARROW BAND OF LIGHT SNOW JUST ENTERING THE DEVILS
LAKE BASIN. RAP SOUNDING AT KDVL SUGGESTS THERE MAY BE SOME
FREEZING DRIZZLE MIXED IN...BUT UPSTREAM OBSERVATIONS THUS FAR
HAVE BEEN ALL SNOW. PRIMARY MID-LEVEL WARM AIR ADVECTION SNOW
STILL STRETCHES FROM KENMARE TO GARRISON AND WILL IMPACT THE
REGION LATER THIS AFTERNOON AND EVENING. ALSO INTRODUCED SOME 20
POPS ACROSS THE LAKE OF THE WOODS REGION LATE THIS MORNING FOR
SOME LIGHT SNOW BEING REPORTED AT ROSEAU...BAUDETTE AND WASKISH.

TEMPERATURE/SKY/WIND GRIDS ARE IN GOOD SHAPE WITH NO MAJOR CHANGES
AT THIS TIME.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY NIGHT)
ISSUED AT 418 AM CST SUN DEC 1 2013

00Z/06Z MODELS ARE COMING MORE IN LINE TOWARD A GENERAL CONSENSUS
SOLUTION...WITH THE GFS REMAINING A FAST OUTLIER. EVEN THE NAM IS
SIMILAR TO THE CONSENSUS...JUST STRONGER. THE IDEA IS THAT AN
UPPER LOW WILL DIG INTO THE NORTHWEST CONUS/NORTHERN
ROCKIES...THEN EJECT INTO NORTHERN MINNESOTA BY 12Z WED. MODELS
HAVE REMAINED CONSISTENT INDICATING 3 ROUNDS OF SNOWFALL.

THE FIRST ROUND WILL BE LATER THIS AFTERNOON INTO TONIGHT.
FORCING IS WEAK AND AVAILABLE MOISTURE IS RELATIVELY
LOW...THINKING UP TO AN INCH OF SNOWFALL IS MOST LIKELY.

THE SECOND WAVE (MONDAY INTO MONDAY NIGHT) IS STRONGER...WITH MORE
AVAILABLE MOISTURE (PWATS APPROACHING 0.5 INCHES). MODELS INDICATE
A DEFINED CIRCULATION AT 850MB (AND A WEAK 700MB LOW) PROPAGATING
FROM NW ND INTO WESTERN MN ON MONDAY...LOSING DEFINITION MONDAY
NIGHT AS IT PROPAGATES FURTHER TO THE EAST. ASSOCIATED WARM AIR
ADVECTION/FRONTOGENESIS COMBINED WITH THE 0.5 INCH PWATS SHOULD
LEAD TO A BAND OF SNOWFALL MOVING THROUGH THE REGION. MODELS
INDICATE 0.20-0.40 INCHES QPF ACROSS ALL BUT THE NE FA...AND
COMBINED WITH 12:1-13:1 SNOW RATIOS WOULD LEAD TO AN AREA OF 2-5
INCHES OF SNOW. MODELS INDICATE THAT THE MESOSCALE FORCING IS
RELATIVELY WEAK...WHICH WOULD MEAN THE MODELS SHOULD BE IN THE
BALL PARK WITH QPF.

THE THIRD ROUND OF SNOWFALL (TUESDAY-TUESDAY NIGHT) WILL BE
ASSOCIATED WITH THE MAIN STRONG MID-LEVEL LOW MOVING THROUGH THE
REGION. THE 00Z ECMWF IS SLIGHTLY FASTER WITH THIS FEATURE.
SYNOPTIC FORCING WILL BE VERY STRONG...WITH THE POTENTIAL FOR
MESOSCALE BANDING. WITH THAT SAID...THIS ROUND OF SNOWFALL STILL
HAS THE MOST UNCERTAINTY (DUE TO MODEL DIFFERENCES). GIVEN THE
AVAILABLE MOISTURE (PWATS 0.5+ INCHES) AND STRONG FORCING
EXPECTED...ALONG WITH THE SLOW MOVING NATURE OF THE SYSTEM...THIS
ROUND SHOULD BRING 6+ INCHES (CURRENT THOUGHTS ARE 5 TO 10 INCHES)
TO MOST AREAS. SOMETIME TOWARD THE TAIL END OF THE
SNOWFALL...WINDS SHOULD INCREASE...LIKELY STRONG ENOUGH FOR
BLOWING SNOW ISSUES.

SINCE THE TRUE WINTER WARNING CONDITIONS WILL LIKELY NOT OCCUR
UNTIL SOMETIME ON TUESDAY...WILL HOLD OFF ON ISSUING ANY
WINTER HEADLINES. THIS WILL ALLOW FOR ANOTHER SET OF MODEL RUNS TO
INCREASE CONFIDENCE. COULD SEE A SITUATION WHERE WE HAVE ADVISORY
CONDITIONS ON MONDAY/MONDAY NIGHT FOLLOWED BY A SHORT BREAK...THEN
WARNING CRITERIA SNOW TUESDAY/TUESDAY NIGHT (WITH WINDS AND
BLOWING SNOW LATER TUESDAY NIGHT INTO WEDNESDAY). WILL ADD SOME
DETAIL TO THE SPECIAL WEATHER STATEMENT AND HWO.

.LONG TERM...(WEDNESDAY THROUGH SATURDAY)
ISSUED AT 418 AM CST SUN DEC 1 2013

WEDNESDAY-SATURDAY...BOTH THE GFS/ECMWF INDICATE SNOW WINDING
DOWN ON WEDNESDAY AS THE SFC LOW PULLS AWAY. DESPITE A TREND
TOWARDS A FASTER SOLUTION...THERE IS STILL SOME UNCERTAINTY WITH
THE 00Z GEM SLOWER WITH THE SFC LOW...KEEPING SNOW AROUND THROUGH
WEDNESDAY NIGHT. SOME LIGHT SNOW/SNOW SHOWERS COULD LINGER INTO
LATE WEEK AS A REINFORCING UPPER LOW PIVOTS SOUTHWARD INTO THE
REGION...MAINTAINING CYCLONIC FLOW. HOWEVER...THE MAIN CONCERN FOR
THE REMAINDER OF THE WEEK WILL BE TEMPS AS A BITTERLY COLD ARCTIC
AIR MASS TAKES UP RESIDENCE ACROSS THE NORTHERN PLAINS. BASED ON A
MORE PROGRESSIVE SOLUTION...STRONG LOW-LEVEL COLD ADVECTION MAY
PREVENT MUCH TEMPERATURE RISE ON WEDNESDAY. 1000-500 MB
THICKNESSES FALL BELOW 500 DAM BY THURSDAY/FRIDAY...WITH HIGHS NO
HIGHER THAN THE LOW SINGLE DIGITS. MODELS INDICATE THE SFC HIGH
AXIS DOES NOT APPROACH UNTIL NEXT WEEKEND. THUS...WITH ONLY A
GRADUAL SLACKENING OF THE PRESSURE GRADIENT...WINDS WILL REMAIN UP
A BIT THROUGH THE WORK WEEK. THE COMBINATION OF WINDS AND BITTERLY
COLD TEMPS LIKELY WILL LEAD TO DANGEROUS WIND CHILLS AT TIMES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z MONDAY MORNING)
ISSUED AT 650 AM CST SUN DEC 1 2013

IFR CONDITIONS WILL LIKELY CONTINUE THROUGH THE MORNING
HOURS...GRADUALLY RISING WITH DAYTIME HEATING (BUT NOT GREATER
THAN MVFR CRITERIA). 10Z RAP GUIDANCE SHOWS THE POTENTIAL FOR A
PERIOD OF VFR CONDITIONS TONIGHT AS LOW LEVEL FLOW INCREASES. THIS
SEEMS LIKE A LOW PROBABILITY OF OCCURRENCE CONSIDERING THAT THE
LOW-LEVEL AIRMASS IS EXPECTED TO REMAIN SATURATED. WILL MONITOR
THE SITUATION AND ADJUST THE FORECASTS AS NEEDED.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...DENSE FOG ADVISORY UNTIL 3 PM CST THIS AFTERNOON FOR NDZ006-007-
     014-015-024-026-028-038-049-052.

MN...NONE.
&&

$$

UPDATE...ROGERS
SHORT TERM...TG
LONG TERM...MAKOWSKI
AVIATION...TG