Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 221445
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
845 AM CST MON DEC 22 2014

.UPDATE...
ISSUED AT 845 AM CST MON DEC 22 2014

ISSUED A WINTER WX ADVISORY FOR THE DEVILS LAKE BASIN. GETTING
NUMEROUS REPORTS OF DRIZZLE...AND WITH TEMPERATURES BELOW FREEZING
SOME SIDEWALKS AND ROADS (ESPECIALLY UNTREATED ROADS) ARE ICY. INCOMING
MODEL GUIDANCE INDICATES THAT FORCING WILL STRENGTHEN ACROSS THIS
AREA TODAY INTO TONIGHT...AND MODEL SOUNDINGS CONTINUE TO INDICATE
A DRY LAYER ALOFT THROUGH TONIGHT. THE MAIN QUESTION WILL BE
WHEN/IF THE SFC TEMPERATURE WILL GET ABOVE FREEZING. MOST GUIDANCE
SAYS NO...ALTHOUGH MOISTURE/TEMP ADVECTION MAY BE STRONGER THAN
WHAT MODELS INDICATE. MOST LOGICAL SOLUTION IS THAT IF IT DOES GET
ABOVE FREEZING...IT WOULD BE SHORT LIVED AND BACK BELOW FREEZING
THIS EVENING. NOT SURE WHEN/IF A CHANGEOVER TO SNOW WILL
OCCUR...BUT WILL DELAY SNOW MENTION UNTIL LATER TONIGHT.

THE REMAINDER OF THE FA WILL LIKELY REMAIN DRIZZLY THROUGH
TODAY...BUT WITH TEMPERATURES ABOVE FREEZING.

UPDATE ISSUED AT 705 AM CST MON DEC 22 2014

WENT AHEAD AND ISSUED A DENSE FOG ADVISORY FROM BARNES DOWN
THROUGH SARGENT COUNTIES AS VSBYS HAVE DROPPED IN THE PAST FEW
HOURS. THE VSBYS WILL NEED TO BE RE-EVALUATED LATER THIS MORNING. IN
AREAS WHERE SFC TEMPS ARE AT OR BELOW FREEZING...THE WET ROAD
SURFACES WITH THE FOG AND FREEZING DRIZZLE IS MAKING FOR ICY
ROADS. REPORTS FROM VALLEY CITY AND ALSO PARTS OF THE DEVILS LAKE
BASIN INDICATE THE PRESENCE OF A GLAZE OF ICE. WILL ISSUE AN SPS
FOR NOW AND CONTINUE TO RE-EVALUATE THIS MORNING.

&&

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 346 AM CST MON DEC 22 2014

THE FORECAST THIS MORNING FOCUSES ON THE LIGHT MIXED PRECIP EVENT
EARLY THIS WEEK.

SFC LOW OVER WESTERN DAKOTAS THIS MORNING WILL DIVE SOUTHEAST TO S IOWA
TONIGHT BEFORE LIFTING UP THROUGH THE GREAT LAKES. FORECAST MODELS
HAVE CONTINUED TO HANDLE THIS EVENT POORLY...SO CONFIDENCE
CONTINUES TO BE ON THE LOW SIDE...BUT THE OVERALL TREND HAS BEEN
FOR A WEAKER SYSTEM/LESSER IMPACTS.

THE REGION REMAINS SOCKED IN UNDER LOW CLOUDS...WITH SOME PATCHES
OF FOG EARLY THIS MORNING. TEMPS HAVE REMAINED STEADY OR HAVE
SLOWLY RISEN OVERNIGHT IN THE 30S.

EARLY THIS MORNING...REGIONAL RADAR INDICATED PRECIP DEVELOPMENT
TO THE SOUTH OVER SD/NE. THE GENERAL IDEA IS THAT SOME LIGHT
PRECIP WILL DEVELOP DURING THE MORNING OVER THE AREA AND SPREAD
NORTHWARD. DID CONTINUE HIGH POPS...ALTHOUGH EXPECT PRECIP TO BE
VERY LIGHT TODAY...GIVEN THE WEAK FORCING MOSTLY RELEGATED TO THE
LOW LEVELS. POP TRENDS MAY NEED TO BE ADJUSTED DURING THE
DAY...PENDING HOW ORGANIZED PRECIP BECOMES. PRECIP TYPE WILL ALSO
BE AN ISSUE. LOW LEVEL THERMAL PROFILES GENERALLY WILL BE WITHIN A
FEW DEGREES OF 0C UP TO ABOVE 900 MB...MAKING FOR A TRICKY
FORECAST...BUT WITH SFC TEMPS INTO THE MID 30S IN SPOTS...MAY BE
CONTENDING WITH LIGHT RAIN/DRIZZLE AT TIMES OVER PARTS OF THE VALLEY.
THE AIR MASS WILL BE QUITE MOIST...WITH SEASONABLY HIGH PW VALUES
APPROACHING 0.50 INCHES.

TONIGHT THERE IS PERHAPS A BIT BETTER LOW-LEVEL ISENTROPIC
LIFT/DEFORMATION THAT MODELS FOCUS ACROSS SE ND. WITH CONTINUED
MOIST AIRMASS IN PLACE...TEMPS WILL NOT DROP OFF MUCH. AS A
RESULT...PRECIP TYPE WILL STILL BE A CONCERN IN SOME AREAS. RIGHT
NOW HAVE TRENDED FROM RA/SN TO LIGHT SNOW...BUT WITH LOW-LEVELS
ALREADY SATURATED...AND ONLY SLOW COOLING OF THE LOWER
TROPOSPHERE...THIS TRANSITION WILL NEED TO BE WATCHED. EVERYTHING
CONSIDERED...DO NOT EXPECT HEAVY PRECIP RATES...BUT LOCATIONS
WITHIN MORE PERSISTENT PRECIP BANDS WHERE MORE SNOW DOES OCCUR
COULD PICK UP SOME ACCUMULATIONS UP TO A FEW INCHES THROUGH
TUESDAY. OVERALL...IT DOES NOT CURRENTLY APPEAR THAT THIS SYSTEM
WILL HAVE DRAMATIC IMPACTS FOR THE REGION...BUT STILL SOME
UNCERTAINTY ON THE DETAILS.

TEMPS WILL REMAIN MILD ON TUESDAY WITH WHAT MODEST 850 MB COLD
ADVECTION THERE IS FOCUSED ACROSS CENTRAL ND...BEHIND THE
INCREASINGLY VERTICALLY STACKED LOW. THAT SAID...WINDS WILL BE A
BIT GUSTY ESPECIALLY WEST OF THE VALLEY DURING THE DAY.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 346 AM CST MON DEC 22 2014

SOME LIGHT SNOW MAY LINGER TUES NIGHT ALONG AND EAST OF THE
VALLEY. OTHERWISE...TEMPS WILL REMAIN MILD ON WEDNESDAY AS THE
UPPER AIR FLOW BRIEFLY BECOMES QUASI-ZONAL OVER THE NORTHERN
PLAINS. A SHORTWAVE TROUGH/SFC LOW PUSHING ACROSS SOUTHERN CANADA
MAY BRUSH CANADIAN BORDER AREAS WITH SOME LIGHT SNOW LATER WED/WED
NIGHT...BUT VERY MINOR.

FOR THURSDAY THROUGH SUNDAY PERIOD...MODELS MAINTAIN DIFFERENCES
WITH RESPECT TO NEXT SYSTEM TO MOVE IN FROM THE PAC NW AND
EAST-SOUTHEAST INTO THE NRN PLAINS THU NIGHT-FRI.  PREFER THE
FARTHER SOUTH SOLN OF EMCWF/GEM VS NRN SOLN OF GFS DUE TO STRONG JET
LIKELY TO HELP DIG THE UPPER SYSTEM FARTHER SOUTH THAN MODELS
SHOW...JUST LIKE THIS CURRENT SYSTEM TODAY. WILL MAINTAIN SOME
SLIGHT POPS THOUGH...MAINLY SOTUEHRN HALF OF FCST AREA.  AFTER THIS
COLDER AIR MOVES IN AS TEMPS DROP BACK TO CLOSER TO MORE NORMAL LATE
DECEMBER VALUES.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 705 AM CST MON DEC 22 2014

GENERALLY EXPECT CEILINGS UNDER IFR THRESHOLDS THROUGH MUCH OF THE
PERIOD. THERE WILL BE AREAS OF MIST AND DRIZZLE AND REDUCED VSBY...WITH
SOME LIGHT RAIN/SNOW SPREADING NORTHWARD TODAY. A GRADUAL
TRANSITION TO ALL SNOW IS EXPECTED TONIGHT.


&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ006-007-
     014-015-024-026-028-054.

     DENSE FOG ADVISORY UNTIL 10 AM CST THIS MORNING FOR NDZ038-049-
     052.

MN...NONE.
&&

$$

UPDATE...TG
SHORT TERM...MAKOWSKI
LONG TERM...MAKOWSKI/RIDDLE
AVIATION...MAKOWSKI






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