901 
FXUS63 KFGF 211607
AFDFGF

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
1107 AM CDT SAT JUL 21 2012

.DISCUSSION...
UPPER LEVEL RIDGE AXIS OVER EASTERN MT WILL MOVE SLOWLY EAST TODAY. 
WEST NORTHWEST FLOW ALOFT WILL PROVIDE LARGE SCALE SUBSIDENCE ACROSS 
THE FORECAST AREA. SURFACE HIGH PRESSURE OVER SOUTHWEST MAN WILL 
MOVE INTO NORTHWEST MN THIS AFTERNOON AND WILL PRODUCE RELATIVELY 
LIGHT EAST OR NORTHEAST WINDS.. MOIST TROPICAL AIR HAS BEEN 
TEMPORARILY BEEN PUSHED INTO SD AND SOUTHERN MN. LOWER PRECIPITABLE 
WATER WILL BRUSH THE NORTHEAST ZONES TODAY. RAISED TEMPS A TAD FOR 
TODAY.

&&

.AVIATION...
SATELLITE AND SURFACE OBS INDICATED SOME CLOUDS ABOVE 10 THOUSAND FT 
OVER NORTH CENTRAL ND. CLOUDS MAY MOVE ACROSS THE NORTHERN ZONES 
THIS AFTERNOON. OTHERWISE VFR CONDITIONS EXPECTED FOR TODAY. 

&&

.PREVIOUS DISCUSSION.../ISSUED 303 AM CDT SAT JUL 21 2012/

PRECIP CHANCES WILL BE THE PRIMARY FORECAST ISSUE THROUGHOUT THE PERIOD.

SFC BOUNDARY HAS MOVED SOUTH OF THE CWA AND CONVECTIVE DEVELOPMENT
HAS FOR THE MOST PART STAYED OVER SD AND CENTRAL MN. THERE MAY BE
A FEW SHOWERS IN THE SOUTHERN COUNTIES BEFORE SUNRISE BUT WITH
HIGH PRESSURE BUILDING IN AND DRIER AIR MOVING IN FROM THE
NORTHEAST THINK THAT PRECIP CHANCES WILL BE PRETTY MINIMAL AFTER
12Z. WITH DRIER AND MOST STABLE AIR ALONG WITH UPPER RIDGING
CONTINUING TO BUILD OVER THE PLAINS...THE MAIN ISSUE TODAY WILL BE
TEMPERATURES. THERE WILL CONTINUE TO BE PLENTY OF SUN AND DECENT
MIXING FROM NORTHEASTERLY WINDS...BUT SOME WEAK COLD AIR
ADVECTION. WILL CONTINUE TO KEEP HIGHS A FEW DEGREES COOLER THAN
YESTERDAY...MAINLY IN THE 80S.

A WEAK SHORTWAVE TROUGH WILL BEGIN TO MOVE OVER THE TOP OF THE
UPPER RIDGE TONIGHT...WITH A SFC TROUGH DEVELOPING OVER WESTERN ND
AND SOUTHERLY WINDS BRINGING SOME RETURN FLOW OF MOISTURE. MODELS
ARE IN FAIRLY DECENT AGREEMENT ON DEVELOPING TWO LOW PRESSURE
CENTERS BY 12Z SUNDAY...ONE OVER SD AND ANOTHER OVER MANITOBA. NAM
HAS MOST OF THE PRECIP STAYING TO OUR SOUTH AND NORTH BUT THE
GLOBAL RUNS ARE A BIT MORE BULLISH ON QPF. BEST CHANCES AFTER
MIDNIGHT TONIGHT LOOK TO BE IN THE DEVILS LAKE BASIN AND IN THE
FAR SOUTHERN COUNTIES...SO TWEAKED LOW POPS TO FIT. DURING THE DAY
ON SUNDAY...THE SHORTWAVE OVER MANITOBA BECOMES STRONGER...AND
SHOULD HELP PUSH A COOL FRONT INTO THE CWA AS IT MOVES SOUTHEAST.
THERE COULD BE SOME DECENT DESTABILIZATION AHEAD OF THE FRONT BY
SUNDAY AFTERNOON. THERE COULD BE SOME CAPPING HOWEVER...AND
THE NAM AND ECMWF HAVE THE CAP HOLDING AND THE FRONTAL BOUNDARY
PASSING THROUGH WITHOUT MUCH PRECIP...WHILE THE GFS IS BETTER ON
BREAKING OUT SOME ACTIVITY ALONG THE BOUNDARY. GIVEN THE WAY
THINGS HAVE BEEN GOING THIS SUMMER AND THE GFS TENDENCY TO OVERDO
DEW POINTS LEANED A BIT MORE IN THE DRIER DIRECTION.  FOR NOW HAVE
SOME LOW POPS IN THE NORTHEASTERN COUNTIES SUNDAY AFTERNOON WHICH
WILL BE CLOSEST TO THE UPPER SYSTEM AND HAVE BETTER LIFT.

CONDITIONS SHOULD BE FAIRLY QUIET AND A FEW DEGREES COOLER SUNDAY
NIGHT AND MONDAY AS NORTHERLY WINDS BRING WEAK COOL AIR ADVECTION
AND DRIER AIR BACK IN WITH HIGH PRESSURE. ANOTHER SHORTWAVE TROUGH
BEGINS TO APPROACH ON MONDAY NIGHT...SO KEPT LOW POPS GOING IN THE
WESTERN COUNTIES.  

LONG TERM (TUESDAY-FRIDAY)...
THE MAIN FORECAST CHALLENGE DURING THIS PERIOD CONCERNS TIMING AND 
LOCATION OF PRECIP. THE UPPER FLOW IS EXPECTED TO TRANSITION TO THE 
SOUTHWEST TUE-WED...AS A CLOSED UPPER LOW SLOWLY SHIFTS EAST FROM 
THE CANADIAN ROCKIES. THE MEDIUM RANGE MODELS HAVE COME INTO BETTER 
AGREEMENT REGARDING THE OVERALL PATTERN AND SLOWER PROGRESSION OF 
THE UPPER WAVE...BUT UNCERTAINTY REMAINS IN THE FORECAST DETAILS. 
WEAK SHORTWAVE TROUGHS EMBEDDED IN THE SOUTHWEST FLOW COMBINED WITH 
LOW-LEVEL WARM AIR ADVECTION NORTH OF THE 850 MB THERMAL RIDGE 
STRETCHING NW TO SE TO THE SOUTH OF THE CWA WILL RESULT IN CHANCES 
FOR SOME SHOWERS AND THUNDERSTORMS TUE INTO WED. 

THE CLOSED UPPER LOW IS EXPECTED TO SHIFT INTO MANITOBA ON THUR 
BEFORE DIVING INTO THE UPPER GREAT LAKES ON FRI. RIGHT NOW HAVE THE 
HIGHEST POPS WED NIGHT AND THUR ACROSS THE NORTHERN AND EASTERN 
PARTS OF THE CWA...CLOSER TO THE STRONGER FORCING FROM THE WAVE. 
HIGH PRESSURE BUILDING IN BEHIND THE SYSTEM FOR FRIDAY SHOULD PUT AN 
END TO THE PRECIP. TEMPS LOOK TO REMAIN A BIT ABOVE NORMAL FOR MUCH 
OF THE PERIOD...WITH HIGHS MAINLY IN THE 80S AND LOWS IN THE 60S.

&&

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

$$

HOPPES