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Area forecast discussion 
National Weather Service Grand Forks ND 
650 PM CDT sun Mar 21 2010 




Aviation...update for 00z tafs... 
mainly VFR conditions expected through taf period with an increase in middle and 
high clouds. Exception will be kdvl...where approaching low pressure and 
cold front will bring an increase in MVFR ceilings after 18z...possibly 
some IFR ceilings with -ra after 20z. Winds will generally be from a srly 
component through the period. 


&& 




Short term... 
the main forecast challenges are temperatures and precipitation. 
When looking at the latest surface analysis...an area of high 
pressure is centered in central Manitoba...with a ridge axis 
extending into central Minnesota. When comparing the models...the models 
remain in pretty good agreement for the short term forecast...so 
ended up using a blend of the GFS and the NAM for the forecast. 


The surface high pressure ridge will continue to move east tonight... 
with S return flow continuing. Thus...expecting low temperatures tonight to 
remain near or slightly warmer than last night. 


On Monday and Tuesday...a clipper starts moves through the North Plains... 
bringing a chance of rain on Monday afternoon. Then...as the low 
passes and colder air returns to the North Plains on Monday night and 
Tuesday...expect precipitation to change from rain to a rain/snow mix and even 
to snow before ending Tuesday afternoon. Precipitation totals will be 
light...with less than one tenth of an inch expected and a 
dusting at best for any snowfall accumulation. 


Another high pressure ridge builds in for Tuesday night and Wednesday... 
keeping the area dry...with temperatures near normal. 


Long term... 
the main challenges in the long term forecast are the temperatures. 
The sun is becoming ever more powerful...so cloud cover will be very 
important to the temperature forecast. Plus...the timing and 
strength of a cold front Wednesday night will really affect temperatures 
too. The models are in decent agreement...except for the Gem which 
seems too warm. Therefore...leaned on the GFS and European model (ecmwf). 


It currently looks like a cold front associated with the Alberta 
clipper will swing through the North Plains Wednesday night. Would not be 
surprised if this timing changes over the coming days...but the 
models are in good agreement right now with Wednesday night. This will 
bring high pressure and cooler weather Thursday and Thursday night. The 
high pressure should advance east Thursday night. This could be followed 
by a low pressure system that will develop east of The Rockies... 
increasing cloud cover for Friday. There is a slight chance of 
precipitation Friday and Friday night...probably a mix of snow and 
rain...but it does not appear to be anything heavy. 


&& 


Hydrology... 
major and moderate flooding continues along the Red River from 
Wahpeton to Oslo with major and moderate flooding expected at 
Drayton and Pembina by the end of the month. The broad crest wave is 
in the Fargo...Moorhead area today...as river levels have flat 
lined near 37 feet. The projected crest arrivals for Grand Forks 
are on Tuesday and into the Oslo area by Thursday. The crest is expected 
to be in Drayton next weekend and in Pembina by the end of the 
month. No significant precipitation is expected to influence the 
Red River levels this week. Ice in the Main Channel will continue 
restricting flow in the from Oslo to the Canadian border. 


Warmer temperatures today and Monday may cause some snow melt runoff 
to once again make rivers levels to rise along the Sheyenne river 
at Valley City and Lisbon and along the Park River at Grafton. 


Backwater from the main Stem red continues prolong flood waters at 
the following locations...West Fargo...Harwood...Hendrum...Shelly 
and Climax. Areal flood warnings continue for all counties along the 
Red River as overland flooding continues to make its way into the 
river system. South bound lanes of Interstate 29 have been reported 
to have a foot a water flowing on them just south of Harwood. 


The river gage at Hawley is malfunctioning. A secondary sensor 
indicates that the river is still falling and should fall below 
flood stage on Monday...as forecast. 


&& 


Fgf watches/warnings/advisories... 
ND...areal Flood Warning for Richland...Ransom...Sargent...Cass... 
Barnes...trail...Steele...Griggs...Grand Forks...eastern Walsh... 
and Pembina counties. 


Minnesota...areal Flood Warning for Kittson...western Marshall...western 
Polk...Norman...Clay and Wilkin counties. 


&& 


$$ 
Ng/g2/dlh/jk