Area Forecast Discussion
Issued by NWS Grand Forks, ND

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FXUS63 KFGF 221850
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1250 PM CST MON DEC 22 2014

.UPDATE...
ISSUED AT 1250 PM CST MON DEC 22 2014

DENSE FOG REMAINS ACROSS BARNES COUNTY AND WILL EXTEND THE DENSE
FOG ADVISORY FOR THIS AREA UNTIL 22Z. WINDS REMAIN LIGHT...BUT
GUIDANCE SUGGESTS THAT THEY WILL INCREASE BY 22Z...THUS MIXING THE
LOWER LEVELS AND IMPROVING VSBY (JUST LIKE WHAT OCCURRED JUST SOUTH
OF THIS LOCATION).

MOST ROADWAYS ARE MORE WET THAN ICY ACROSS THE DEVILS LAKE
BASIN...WITH TEMPERATURES NEAR OR SLIGHTLY ABOVE FREEZING.
TEMPERATURES SHOULD AGAIN FALL LATER THIS AFTERNOON...WITH DRIZZLE
CONTINUING. NOT SURE HOW QUICKLY A CHANGEOVER TO SNOW MIGHT OCCUR
(DEPENDS ON HOW QUICKLY THE UPPER LEVELS SATURATE)...BUT EITHER
WAY (MORE SNOW ON TOP OF LITTLE ICE OR LITTLE SNOW ON TOP OF MORE
ICE) HAZARDOUS TRAVEL EXPECTED AND WINTER WX ADVISORY WARRANTED.
UPDATED THE WSW TO REFLECT THIS THINKING.

WILL BE TAKING A CLOSER LOOK AT SNOW AMOUNTS FOR THE NEXT UPDATE.
LOW LEVEL MOISTURE IS RATHER HIGH ATTM...AND NOT SURE HOW MUCH
COOLING WILL BE ABLE TO OCCUR NEAR THE SFC (AT LEAST ALONG AND
EAST OF THE VALLEY). SNOW WILL EVENTUALLY BECOME THE PREDOMINANT
PTYPE...BUT MOST AREAS UP TO AN INCH SEEMS REASONABLE (MAYBE 2-3
IF SNOW BEGINS SOONER THAN EXPECTED). WEST OF THE VALLEY...THE
RAIN/SNOW LINE THIS AFTERNOON WILL BE NEAR THE SOUTHWEST FA...BUT
LIKELY WILL BE WEST OF THIS FA WITH MOSTLY RAIN...THEN SNOW THIS
EVENING WITH 1-3 INCHES OF SNOW (VALLEY CITY SOUTHWARD).

&&

.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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1250 PM CST MON DEC 22 2014

IFR/LIFR CONDITIONS REMAIN WIDESPREAD ACROSS THE AREA WITH MIST AND
LIGHT DRIZZLE...CHANGING TO ALL SNOW GENERALLY AFT 00Z.
OTHERWISE...STAYED WITH PERSISTENCE FOR THIS TAF PERIOD AS NOT
SEEING SIGNIFICANT CHANGES IN THE AIRMASS. VISIBILITIES ARE EXPECTED
TO FLUCTUATE AND SHOW SOME IMPROVEMENT IN AREAS...BUT OVERALL TREND
IS TO REMAIN MAINLY IN THE IFR CATEGORY.

&&

.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 4 PM CST THIS AFTERNOON FOR NDZ038.

MN...NONE.
&&

$$

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






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