291 
FXUS63 KFGF 290202
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
802 PM CST MON JAN 28 2013

.DISCUSSION...

CURRENT HEAVY SNOW BAND HAS DEVELOPED AS PROGGED...AND WINTER
STORM WARNING HEADLINES LINE UP WELL WITH CURRENT BAND. REPORTS SO
FAR INDICATE ABOUT 2-4 INCHES HAS FALLEN FROM AROUND FARGO
SOUTHWEST TO LIDGERWOOD...WITH LOCALLY HIGHER AMOUNTS LIKELY NEAR
GWINNER/LIDGERWOOD WHERE 1/4SM VSBYS HAVE BEEN COMMON OVER THE PAST FEW
HOURS. THE SNOW BAND WILL CONTINUE TO BE FED BY PWATS OVER 0.50
INCHES AND STRONG 850-700MB FGEN AIDING OMEGA FIELDS...AND EXPECT
IT TO SLOWLY MOVE SOUTH AND EAST OVERNIGHT. THERE IS ALSO UPPER LEVEL
DIVERGENCE AND A SHORTWAVE MOVING THROUGH SW FLOW ALOFT. THERE IS
NO SFC WINDS TO SPEAK OF...SO THIS IS A CLASSIC NARROW/DEFORMATION/FGEN
SNOW BAND WHERE 6-8 INCHES WILL BE COMMON IN THE CENTER...WITH
LOCALIZED HIGHER AMOUNTS NEAR PERSISTENT HEAVIER BANDS. THE SNOW
DISSIPATES QUICKLY TO THE NORTH AND NO SNOW HAS FALLEN IN WESTERN
POLK...TRAILL OR STEELE COUNTIES...SO WILL BE CAN CELLING THE
WINTER WEATHER ADVISORIES HERE. WE COULD BE CLOSE TO WARNING
CRITERIA SNOW IN NORTHERN BELTRAMI...BUT THINKING IT SHOULD BE
AROUND 5 INCHES HERE SO WILL HOLD ON A WARNING HERE...BUT MONITOR
OVERNIGHT. WE WILL TRIM SNOW AMOUNTS ON THE NORTHERN FRINGE OF THE
HEAVIER SNOW BAND...BUT OVERALL NOT MUCH CHANGE IS NEEDED WITH
THIS HEAVY SNOW BAND.

&&

.AVIATION...

THE MAIN RESTRICTION TO VSBY WILL BE IN HEAVY SNOW BAND IN THE
SOUTH OVERNIGHT. THERE IS STILL SOME PATCHY FOG THOUGH IN THE
NORTH...WITH IFR/MVFR CONDITIONS NEAR ANY FOG. THERE WILL BE
ANOTHER BAND OF MVFR CIGS DROPPING SOUTH TOMORROW WITH COLDER AIR
FILTERING INTO THE AREA AND INCREASING NORTHERLY WINDS BEHIND COLD
FRONT.

&&

.PREV DISCUSSION... /ISSUED 348 PM CST MON JAN 28 2013/ 

DISCUSSION...FORECAST CHALLENGE WILL BE POTENTIAL HEAVY SNOW AND
TEMPERATURES. MODELS IN GOOD AGREEMENT WITH TRACK OF EXPECTED
HEAVY SNOW. 

BAND OF SNOW WHICH WILL BECOME HEAVY AT TIMES IS SETTING UP ABOUT
AS EXPECTED FROM CENTRAL SD THROUGH SE ND. THIS ASSOCIATED WITH NE
LIFTING SHORTWAVE COMBINED WITH IMPRESSIVE BAND OF FRONTOGENETIC
FORCING. THIS SCENARIO WILL LEAD TO A RELATIVELY NARROW BUT
INTENSE BAND OF SNOW. MODELS HAVE SHIFTED SNOW BAND SLIGHTLY
NORTHWARD HAVING MAIN SNOW AXIS FROM FAR SW CORNER OF FA NE
THROUGH VCNTY FAR TO BJI/PKD. WITH PRECIPITABLE H2O VALUES OVER A
HALF INCH PLENTY OF AVAILABLE MOISTURE. HAVE ISSUED WINTER STORM
WARNINGS ACCORDINGLY. ISSUED A WINTER WEATHER ADVISORY ON EACH
SIDE OF WARNING HOWEVER WILL LIKELY SEE A SHARP CUT OFF FROM
SIGNIFICANT SNOW FALL TO NEAR NOTHING. INITIAL FREEZING RAIN
POTENTIAL ACROSS SE FA MAY ALSO MAKE FOR CHALLENGING SNOW
FORECAST. EXPECT BAND OF SNOW TO LIFT NE DURING THE EVENING AND
NOT LIKELY TO TAPER OFF UNTIL LATE TONIGHT. TEMPERATURES SHOULD
REMAIN MILD TONIGHT WITH COOLEST TEMPERATURES OVER FAR NW WHERE
COLD ADVECTION KICKS IN LATE TONIGHT.

SNOW SHOULD WIND DOWN TUESDAY AM. STEADY COLD ADVECTION DURING THE
DAY WILL LIKELY LEAD TO MAX TEMPERATURES DURING THE MORNING. COLD
ADVECTION CONTINUES THROUGH MIDWEEK AS ARCTIC AIR DROPS SOUTH.
WITH SURFACE HIGH DROPPING INTO WESTERN DAKOTAS FA WILL STAY
WITHIN ZONE OF SURFACE PRESSURE GRADIENT. THIS ALONG WITH
POTENTIAL FOR CLOUDS MAY LIMIT TEMPERATURE DROP HOWEVER WIND
CHILLS WILL BECOME AN ISSUE. 

LONG TERM (THU NIGHT-MON)...
THE FA WILL REMAIN IN NORTHWEST FLOW ALOFT DURING THE ENTIRE LONG 
TERM PERIOD. THIS WILL RESULT IN A SOUTHWEST TO NORTHEAST THERMAL 
GRADIENT OVER THE AREA AS WELL WITH EACH MODEL SLIGHTLY DIFFERENT. 
DESPITE THESE SLIGHT DIFFERENCES THEY SEEM TO AGREE ON THE TREND BY 
SAT OF NEAR NORMAL TEMPS. THE COLDEST DAY SHOULD BE FRI BEFORE TEMPS 
START CLIMBING BACK TOWARD NORMAL. THERE STILL APPEAR TO BE SOME 
WEAK IMPULSES DROPPING DOWN THRU THE AREA WHICH MAY BRING CHANCES 
FOR LIGHT SNOW FRI/FRI NIGHT AND AGAIN SUN/SUN NIGHT. NEITHER OF 
THESE WEAK IMPULSES SHOULD BRING MUCH FOR ACCUMULATIONS. 

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR NDZ039-049-052-
     053.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR NDZ038.

MN...WINTER STORM WARNING UNTIL 6 AM CST TUESDAY FOR MNZ002-003-
     015>017-022>024-027>030.

     WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR MNZ006-009-
     013-014-031-032-040.

&&

$$
DK