FXUS63 KBIS 280948
AFDBIS
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE BISMARCK ND
335 AM CST SAT NOV 28 2009
.SHORT TERM...TODAY THROUGH MONDAY NIGHT...
THE MAIN FORECAST PROBLEM IN THE SHORT TERM FORECAST DEALS WITH
PRECIPITATION CHANCES AND PRECIPITATION TYPE WITH AN UPPER LEVEL
SHORTWAVE TROUGH MOVING ACROSS THE NORTHERN PLAINS TODAY.
THE NAM...ECMWF AND GFS DEPICT AN UPPER LEVEL SHORTWAVE MOVING FROM
SOUTHERN SASKATCHEWAN THIS MORNING...TO SOUTHERN MANITOBA AND NORTH
DAKOTA BY THIS EVENING...AND INTO MINNESOTA BY SUNDAY MORNING.
CURRENT REGIONAL RADARS INDICATE LIGHT PRECIPITATION OVER NORTHERN
NORTH DAKOTA EXTENDING WESTWARD TO NORTHEASTERN MONTANA. THERE IS
ALSO A SEPARATE AREA OF LIGHT PRECIPITATION EVIDENT OVER
SOUTHEASTERN MONTANA. A COUPLE OF RAWS WEATHER OBSERVATION SITES
OVER NORTHERN NORTH DAKOTA INDICATED SOME PRECIPITATION REACHING THE
GROUND. BUFKIT SOUNDINGS INDICATED THAT PRECIPITATION TYPE COULD BE
SPRINKLES OR FLURRIES OR A MIX WAS POSSIBLE. DECIDED TO KEEP THE
SLIGHT/SMALL CHANCE OF PRECIPITATION MENTION IN FOR WESTERN AND
CENTRAL NORTH DAKOTA TODAY.
AN UPPER LEVEL RIDGE BUILDS IN BEHIND THE TROUGH AND KEEPS SUNDAY
AND MONDAY DRY. AVERAGE TO SLIGHTLY ABOVE AVERAGE TEMPERATURES
SUNDAY...THEN A BIT WARMER ON MONDAY AS WINDS BECOME WEST/SOUTHWEST
AHEAD OF A CLIPPER-TYPE SYSTEM PROGGED TO AFFECT THE STATE ON
TUESDAY. HIGHS TODAY AND SUNDAY FROM THE MID 30S NORTH TO LOWER 40S
SOUTH...WARMING TO THE LOWER 40S NORTH TO AROUND 50 SOUTHWEST ON
MONDAY.
.LONG TERM...TUESDAY THROUGH FRIDAY...
THE GFS AND ECMWF CONTINUE TO ADVERTISE A COLD AIR OUTBREAK OVER THE
NORTHERN PLAINS THROUGH THE END OF NEXT WEEK AS COLD CANADIAN AIR
SURGES SOUTHWARD AT THE BEGINNING OF THE LONG TERM.
TH PERIOD BEGINS WITH A LOW PRESSURE SYSTEM MOVING THROUGH SOUTHERN
CANADA. ALTHOUGH THE MODELS DIFFER ON THE FORECAST TRACK...ALL TEND
TO KEEP THE LOW NORTH OF THE FORECAST AREA WHICH SHOULD KEEP ANY
SIGNIFICANT SNOWFALL OUT OF THE AREA. TUESDAY COULD BE A WINDY DAY
DUE TO THE STRONG PRESSURE GRADIENT...STRONG COLD ADVECTION...AND
POTENTIAL LINK TO STRONG WINDS ALOFT. TUESDAY NIGHT THE SURFACE LOW
AND COLD FRONT WILL EXIT THE REGION INTO THE WESTERN GREAT LAKES.
THE REGION IS UNDER NORTHWEST FLOW ALOFT WITH HIGH PRESSURE ALONG
THE WEST COAST AND A TROUGH ACROSS EASTERN NORTH AMERICA. NORTHWEST
FLOW ALOFT AND NORMAL TO SLIGHTLY BELOW NORMAL TEMPERATURES DOMINATE
THE LONG TERM. WITH NORTHWEST FLOW ALOFT IN PLACE ACROSS THE
NORTHERN PLAINS MULTIPLE DISTURBANCES ARE EXPECTED TO MOVE THROUGH
THE FLOW AND BRING A CHANCE OF PRECIPITATION DAILY WHICH SHOULD
MAINLY FALL AS SNOW. THE GFS IS DRIER THAN THE ECMWF THROUGH THE
PERIOD MAINLY DUE TO A CUT OFF LOW OVER THE SOUTHWESTERN US. THE GFS
CONTINUES TO BE SLIGHTLY FASTER THAN THE ECMWF THROUGH THE PERIOD
WITH MUCH MORE NOTICEABLE DIFFERENCES APPEARING AT THE END OF THE
LONG TERM AS ANOTHER DISTURBANCES APPROACHES THE PACIFIC NORTHWEST.
&&
.AVIATION...AS MENTIONED ABOVE...RADARS CONTINUE TO SHOW PATCHY
AREAS OF POTENTIAL LIGHT PRECIP IN EASTERN MONTANA AND ACROSS MOST
OF NORTH DAKOTA. APPEARS THAT THE PRECIP IS MAINLY VIRGA AS SURFACE
REPORTS OF PRECIP HAVE BEEN SPARSE. FOR NOW WILL STAY WITH A LIGHT
RAIN/DRIZZLE OR LIGHT SNOW FORECAST ALTHOUGH THERE IS POTENTIAL FOR
FREEZING DRIZZLE THIS MORNING. FOG IN THE JAMESTOWN AREA SHOULD
REMAIN ABOVE 2 MILES AS HIGH CLOUDS SHOULD INHIBIT RADIATIONAL
COOLING. CEILINGS HAVE BEEN MAINLY VFR AT OR ABOVE 10 THOUSAND FEET
AGL...ALTHOUGH COULD BE AREAS WITH CEILINGS AROUND 15 HUNDRED FEET
AGL IN THE NORTHWEST. CEILINGS SHOULD TREND ABOVE 3 THOUSAND FEET
AGL BY AFTERNOON.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...JV
LONG TERM...DC/TSW
AVIATION...TSW
