Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
647 PM CDT Sat Sep 20 2014

Update...
issued at 646 PM CDT Sat Sep 20 2014

Main line of severe storms has moved well off to our east...but
some additional storms firing as the next vorticity lobe moves down out
of Canada. Not much instability left to work with...only about 250
j/kg...but some thunder and even pea sized hail is possible for
the next few hours over the northern valley. The activity should
weaken after sunset and move off to the southeast as the vorticity
continues to dig into Minnesota. Adjusted probability of precipitation to reflect this. Clouds
will hang around in the eastern counties but the west will
continue to see a clearing trend. Will continue to keep lows in
the 40s in the west to 50s east.

&&

Short term...(this evening through Sunday night)
issued at 311 PM CDT Sat Sep 20 2014

Main challenges will be any severe weather that lingers into the
late afternoon and also any showers that linger into tonight. As of
middle afternoon the surface boundary had shifted to a krox to kfse to kbwp
line. All the convection was along and just behind this boundary.
Storm Prediction Center has portions of the forecast area ahead of the boundary in a Severe Thunderstorm
Watch until 8 PM...but these storms should clear this forecast area by 4 to 5
PM as they are moving eastward at a good clip. Behind the boundary
over the kdvl region clouds were thinning but northwest winds were
breezy. Water vapor imagery shows a couple areas of compact
spinning...one over central/southeast ND and another one up over the
Manitoba lakes region. Models show the first wave pushing into
central Minnesota by early evening as the Winnipeg lakes wave drops into
northwest Minnesota. This shear axis holds in place overnight generally
providing enough lift for some showers to hang around mainly across
northwest Minnesota. Would also expect more cloud cover east of the valley
with less to the west. The windy conditions over the kdvl region
will probably push toward the Red River valley this evening and then
decrease overnight. Some model solutions keep some showers around
over northwest Minnesota on Sunday morning...but will maintain a dry
forecast to match other adjacent offices. Wind speeds should drop
off Sunday night with a relatively cool night expected.

Long term...(monday through saturday)
issued at 311 PM CDT Sat Sep 20 2014

Surface high pressure in control for Monday into Monday night with the next
chance of rain coming on Tuesday. With the Tuesday system better chances
should be across the southern Red River valley with dry conditions
elsewhere.

For Wednesday through Sat...will start out with the upper low over the forecast area
on Wednesday mainly shifting to the east by Thursday. This will set up a
trough over the West Coast and ridge over the central part of the
country. Therefore after some lingering showers/thunderstorms Wednesday it looks
seasonal for temperatures with minimal chances for precipitation Thursday into Sat.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 646 PM CDT Sat Sep 20 2014

Kbji and kgfk will continue to be impacted by precipitation as the taf
period starts but the convective activity will move off to the
southeast in the next few hours. Conditions will become VFR for
most locations with northwest winds starting to drop off in the
next hour or so. Sref and model guidance shows some lower ceilings
moving down out of Canada and into our eastern counties...so
included some MVFR ceilings for kgfk...ktvf...and kbji later tonight.
All sites should become VFR by the end of the taf period tomorrow.
Winds will remain out of the northwest but should stay below 12
kts after 06z tonight.

&&

Fgf watches/warnings/advisories...
ND...none.
Minnesota...none.
&&

$$

Update...Jr
short term...godon
long term...godon/tg
aviation...Jr

National Weather Service Glossary of Abbreviations