869 
FXUS63 KFGF 230926
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
326 AM CST SAT FEB 23 2013

.SHORT TERM (TODAY-MONDAY NIGHT)...

INITIALLY CLOUDS AND FOG WILL BE THE CONCERN. OTHERWISE...CLOUDS
AND LIGHT SNOW CHANCES WILL BE THE CHALLENGE. 00Z MODELS IN
DECENT AGREEMENT ALTHOUGH WITH DETAIL DIFFERENCES SUNDAY INTO
MONDAY. WILL USE A BLEND FOR THIS FORECAST.

THE FORECAST AREA (FA) IS CURRENTLY STUCK WITHIN A VERY WEAK FLOW
ENVIRONMENT. LOW CLOUDS EXIST ALONG AND EAST OF THE VALLEY. THESE
CLOUDS SEEM TO BE OCCURRING WHERE MODELS SHOW 925MB WINDS CALM TO
5 KNOTS. WILL USE THE RAP AS GUIDANCE FOR WHEN SKIES WILL CLEAR
FROM WEST TO EAST (AS LOW LEVEL FLOW INCREASES). THIS SLOWS THE
CLEARING TREND TODAY. PATCHY DENSE FOG HAS OCCURRED WITHIN THIS
WEAK FLOW ENVIRONMENT...BUT 1/4SM VSBY HAS NOT BEEN CONSISTENT
FROM HOUR TO HOUR. WILL KEEP PATCHY FOG IN THE GRIDS THROUGH THE
MORNING HOURS WHERE CLOUDS (WEAK MIXING) IS EXPECTED...AND MONITOR
FOG CONDITIONS. 

FOR SUNDAY INTO MONDAY...SOUTHERN STREAM ENERGY WILL REMAIN WELL
SOUTH OF THE REGION...BUT THERE WILL BE A WEAK NORTHERN STREAM
WAVE THAT AFFECTS THE REGION DURING THIS TIME. THE ECMWF IS
STRONGER WITH THE RIDGING TO THE EAST...AND KEEPS THIS FEATURE
WEST OF OTHER MODELS (WESTERN DAKOTAS VS EASTERN DAKOTAS) AS IT
DROPS TO THE SOUTH AND INTO THE SOUTHERN STREAM WAVE. THE MAIN
AFFECT OF THIS WAVE WILL LIKELY BE CLOUD COVER...BUT LIGHT SNOW
IS ALSO POSSIBLE. THE EXACT LOCATION OF THIS WAVE WILL DETERMINE
WHERE/WHEN THE LIGHT SNOW OCCURS. IF THE ECMWF IS CORRECT
ACCUMULATIONS WILL BE MAYBE A DUSTING...AND IF THE OTHER MODELS
ARE CORRECT ACCUMULATIONS COULD BE AN INCH OR TWO. WILL MAINTAIN
PREVIOUS FORECAST OF LOW POPS ACROSS THE WESTERN FA WITH ONLY A
DUSTING POSSIBLE (AS PMDHMD PREFERS THE ECMWF).

.LONG TERM (TUESDAY-FRIDAY)...

MODELS CONTINUE TO BE IN FAIR AGREEMENT WITH A QUIET WEATHER PATTERN 
FOR THE CWFA FOR THE EXTENDED TIME FRAME WITH A SPLIT FLOW IN THE 
STORM TRACK. 500MB FLOW WILL TRANSITION FROM AN ARKANSAS CUTOFF LOW 
WITH THE NWERLY ORIENTED TROUGH THROUGH THE NORTHERN US ROCKIES INTO 
A POSITIVE PNA PATTERN...WESTERN RIDGE AND EASTERN TROUGH ACROSS THE 
CONUS...BY THE END OF THE PERIOD. WITH LITTLE UPPER LEVEL ENERGY 
MOVING ACROSS THE AREA ONLY SLIGHT CHC FOR POPS WITH -SN POSSIBLE 
TUE AND WED ACROSS THE SOUTH AND EAST ZONES WITH TEMPS NEAR END OF 
FEB NORMALS. 

&&

.AVIATION...

IFR/LIFR CIGS/VSBY ALONG AND EAST OF THE RED RIVER VALLEY ARE
EXPECTED TO SLOWLY IMPROVE FROM WEST TO EAST TODAY. THE MAIN
QUESTION IS WHEN THIS WILL OCCUR. THE THOUGHT IS THAT AS LONG AS
LOW LEVEL FLOW REMAINS WEAK THE LOW CIGS WILL REMAIN. WILL FOLLOW
MODEL 925MB WINDS ABOVE 5 KNOTS FOR INCREASED LOW LEVEL MIXING AND
CLEARING. THIS CLEARS THE VALLEY TAFS LATE MORNING...AND THE
EASTERN FA (KBJI) SOMETIME TOWARD SUNRISE ON SUNDAY.

&&

.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&

$$
TG/JK