FXUS63 KFGF 060356
AFDFGF
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND FORKS ND
956 PM CST SAT DEC 5 2009
.DISCUSSION...
UPPER LEVEL TROUGH OVER THE AREA WILL CONTINUE MOVING SOUTH THEN
EAST OVERNIGHT.
GFS MODEL SOUNDINGS SUGGEST COOLING AROUND 875 HPA AND INCREASING
MOISTURE BELOW 875 HPA HAS PRODUCED A DECK OF LOW CLOUDS OVER THE
NORTHERN FORECAST AREA. ALSO A BAND OF HIGHER SURFACE DEWPOINTS
ALONG LAKE MANITOBA AND LAKE WINNIPEG. EXPECTED THESE DEWPOINTS TO
SHIFT SOUTH OVERNIGHT. WILL UPDATE ZONES.
&&
.PREVIOUS DISCUSSION.../ISSUED 209 PM CST SAT DEC 5 2009/
MAIN CHALLENGES IN THE SHORT TERM FORECAST ARE CLOUDS TRENDS AND
TEMPS AND THEN WHETHER IT IS WORTH MENTIONING ANY FLURRIES. MODELS
SEEM TO BE IN REASONABLE AGREEMENT...BUT WILL STICK CLOSER TO
FORECAST CONTINUITY TODAY WHICH FAVORS SLIGHTLY COOLER TEMPS.
TONIGHT...STARTING OFF...CLOUD TRENDS ARE ALREADY TRICKY. VISIBLE
SATELLITE IMAGERY SHOWS VERY LITTLE CLOUD COVER OVER THE NORTHERN
RED RIVER VALLEY...BUT IT IS HARD TO PICK OUT THE LOW THIN CLOUDS
DUE TO THE SNOW COVER ON THE GROUND. KHCO HAS INDICATED SOME LOWER
CLOUDS AT TIMES WITH A FEW FLURRIES. SOME CUMULUS HAS POPPED UP
AROUND KBDE WHICH IS ALSO REPORTING SOME VERY LIGHT SNOW. COULD
EASILY GO SUNNY WITH PERIODIC FLURRIES TODAY IT IS SO VARIABLE.
MODELS ARE INDICATING SOME HIGHER RELATIVE HUMIDITY MOVING SOUTH/
SW OUT OF SOUTHWEST ONTARIO TONIGHT. SATELLITE DOES NOT LOOK THAT
IMPRESSIVE THOUGH...SO NOT SURE IT WILL BECOME CLOUDY FOR ALL
AREAS TONIGHT. WITH SNOW COVER AND FAIRLY LIGHT SFC WINDS...WHAT
HAPPENS CLOUDWISE MAKES A HUGE DIFFERENCE TONIGHT. WILL STICK WITH
THE IDEA OF BECOMING MOSTLY CLOUDY AGAIN IN THE NORTH TONIGHT...
BUT WILL BRIEF EVENING SHIFT TO WATCH WHAT HAPPENS THRU THE EARLY
EVENING CLOUDWISE. IF THE UPSTREAM CLOUDS ARE THIN OR DO NOT HOLD
TOGETHER...TEMPS COULD FALL TO FORECAST MINS IN THE EVENING AND
WOULD NEED TO BE LOWERED MORE. DO NOT HAVE A GOOD FEELING ON
KEEPING ANY FLURRIES LINGERING TONIGHT...SO WILL LEAVE THEM OUT
AND LET LATER SHIFTS ADD IF NEED BE.
SUN-TUE...WEAK TROUGHINESS HOLDS OVER THE NORTHERN PLAINS FOR THE
DURATION WITH THE MAIN STORM TRACK DOWN OVER THE CENTRAL PLAINS.
FOR THE MOST PART THE WINDS LOOK TO STAY RELATIVELY LIGHT WITH A
GOOD DEAL OF CLOUD COVER. FLURRIES AGAIN COULD OCCUR WITH ALMOST
ANY DECENT CLOUD BAND...BUT HARD TO FIGURE OUT WHEN THE BEST
CHANCES WOULD BE SO AGAIN WILL LEAVE THEM OUT. TEMPS LOOK TO STAY
FAIRLY CLOSE TO WHAT THEY WERE TODAY FOR HIGHS/LOWS...ALTHOUGH
THERE COULD BE A BIT MORE COOLING. WILL KEEP SOME LOW CHANCES FOR
SNOW IN THE SOUTH AS THE TUE SYSTEM OVER THE CENTRAL PLAINS MOVES
NORTHEAST.
LONG TERM [WED-SAT]...
IT WILL BE A COLD PERIOD WITH THE MAIN COLD WEATHER EVENT COMING IN
JUST BEYOND THIS PERIOD AS A 1050 MB HIGH COMES DOWN FROM YUKON INTO
ALBERTA AND MONTANA EARLY NEXT WEEK. THUS THE MAIN ISSUE IS
TEMPERATURES THROUGH THE EXTENDED AND HOW COLD TO GO. CLOUDS ALWAYS
PRESENT AN ISSUE FOR NIGHTTIME LOWS BUT DAYTIME HIGHS TOO WILL
STRUGGLE TO RISE MUCH AS JUST ENOUGH SNOW COVER OVER THE FCST AREA TO
INHIBIT MUCH WARMING FROM THE WEAK SUN. HPC TEMPS SEEMED TOO WARM
CONSIDERING 850 TEMPS DROPPING INTO THE -18 TO -22C RANGE THIS
PERIOD...SO UPON COLLABORATION AMONG NEIGHBORING OFFICES DECIDED TO
DROP HPC TEMP GUIDANCE 5 DEGREES FOR THURSDAY THROUGH SATURDAY AS A
START. THIS WOULD PUT HIGHS IN THE SINGLE DIGITS AND LOWS FROM ZERO
TO BELOW SOUTH TO 10 TO 15 BELOW FAR NORTH. THIS IS IN LINE TOO
WITH ENVIRONMENT CANADA FCST FOR SOUTHERN MANITOBA FOR THE THU-FRI
TIME PERIOD. WENT DRY THE PERIOD...THOUGH SOME FLURRIES OR SNOW
SHOWERS MAY OCCUR.
&&
.AVIATION...
BAND OF MVFR CLOUDS AND OCCASIONALLY IFR CIGS AND VISIBILITIES WAS
OVER MOSTLY THE NORTHWEST CORNER OR MINNESOTA. FOG LOOP INDICATED
CLOUD DECK HAS INCREASED SOUTHWARD TRAJECTORY TO ABOUT 15 KNOTS.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...NONE.
MN...NONE.
&&
$$
HOPPES
