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fxus63 kbis 200925 
afdbis 


Area forecast discussion 
National Weather Service Bismarck ND 
420 am CDT Sat Mar 20 2010 


Short term...today through Monday night... 
currently...high pressure center was over South Dakota/Wyoming with 
temperatures in the teens over the forecast area. Light southwest 
winds this morning should increase to 10 to 15 miles per hour this afternoon as 
the surface high moves south and the pressure gradient tightens with 
the approach of a cold front moving south out of central Canada. 
This cold front slips southeast today as upper level ridging builds 
into the Dakotas...so expecting moderating temperatures with highs 
in the upper 30s and lower 40s over western and central North 
Dakota. 


Southwest winds continue on Sunday and warming continues despite a 
flattening of the upper level ridge over the Western Plains. 
Expecting temperatures to reach the middle 40s in the Devils Lake basin 
and into the middle 50s in the southwest. 


Low pressure develops over southern Alberta on Monday as a shortwave 
moves across the Pacific northwest and southwestern Canada. This 
will allow southwest/southerly winds to persist over southern 
counties of North Dakota...while winds become more easterly over 
northern North Dakota as the low deepens and a developing frontal 
boundary along the international border divides the warmer Pacific 
air to the southwest from the cooler Hudson Bay airmass to the 
northeast. Upper level energy and low level frontogenesis will aid 
in rising/lifting air and will keep a chance of rain in the 
forecast. Temperatures across the northern tier of counties will 
likely only reach into the lower 40s...while continued warming in 
the southern counties will allow temperatures to rise into the 50s. 


By Monday afternoon the models depict the aforementioned southern 
Alberta low to have developed over the western Dakotas and eastern 
Montana/Wyoming. By Tuesday morning the low is forecast to have 
moved east/southeast and colder air should be pushing into the state 
with northwest winds. A chance of rain or snow Monday night will 
remain in the forecast. 


Long term...Tuesday through Friday... 
some light rain and snow may linger into Tuesday...especially 
east...but little or no additional accumulation is expected. Look 
for cold air advection and cooler temperatures behind the front on Tuesday...from the 
lower 30s northwest to near 40 southeast. Temperatures should 
rebound somewhat on Wednesday. Looking ahead to Thursday and 
Friday...medium range models are indicating relatively cool air in 
place and a potential short wave trough impacting the state Thursday 
night into Friday. The GFS is more bullish will the cold 
air...especially northeast...but the current forecast looks 
reasonable. 


&& 


Aviation... 
expect VFR conditions through the taf period with increasing high 
clouds and a strengthening westerly wind. 


&& 


Hydrology... 
flooding continues across the James basin and Beaver Creek near 
Linton. However snowmelt and runoff are not as robust as earlier in 
the week. River levels at LaMoure and near Ludden dam...and Linton 
are forecast to continue rising this weekend. Pipestem creek at 
Pingree will also remain above flood stage. See the latest warnings 
and advisories for details. 


A Flood Warning for overland flooding continues for 
Dickey...McIntosh...LaMoure and Logan counties today. 


A Flood Warning remains in effect for Apple Creek near Menoken. The 
creek is forecast to remain near flood stage of 15 feet...with minor 
fluctuations...and fall over the next few days. Hydrologic models 
over the past 24 hours have indicated that a second rise is unlikely 
as water is more effectively infiltrating into the ground with 
little to no frost remaining. 


A Flood Watch remains in effect through Sunday for overland and 
river flooding in southwest North Dakota...along and near the little 
Missouri River from Marmarth to Medora. An ice flow was reported 
Friday evening on the little Missouri River in Billings County south 
of Medora...and may reach or be near Medora sometime Saturday 
morning. 


The snowpack still contains large amounts of water across The 
Heart...knife...Souris and upper James basins. These basins will 
have to continue to be monitored for their flood potential in the 
coming weeks. 


Temperatures are forecast to moderate today and into Monday. 
However...overnight temperatures below freezing will shut off the 
melt process...and slow runoff at night. A weak system is forecast 
Tuesday with precipitation amounts one quarter inch or less...with 
another cool down beginning Tuesday. 


&& 


Bis watches/warnings/advisories... 
Flood Watch through Sunday evening for ndz031-032-040-043. 


&& 


$$ 


Short term/hydrology...jv 
long term/aviation...Kinney