Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
652 PM CDT Friday Sep 19 2014

Update...
issued at 651 PM CDT Friday Sep 19 2014

No changes at this time.

&&

Short term...(this evening through Saturday night)
issued at 313 PM CDT Friday Sep 19 2014

Convective chances and strength will be the main forecast problem
for tonight and tomorrow.

WV loop shows the leading shortwave trough that brought the
morning activity moving off into Minnesota while there is another
shortwave upstream over Montana. The first shortwave will move off to
the east overnight and the second more weak wave will come into
the northern plains. The surface trough axis will move off from the
Red River valley into eastern Minnesota...with a weak frontal boundary
dropping into the County Warning Area. The short range models all have some widely
scattered precipitation activity along this boundary as it moves into our
northern counties this evening. After clouds much of the day...the
western half of the County Warning Area has finally cleared out and gained some
surface based instability. There have been towering cumulus and a few radar
returns developing along the surface trough axis in our northern County Warning Area
while the cap has remained in place further south.

Think there will be some convection along the surface boundary it
moves south out of Canada. The best upper support will be over the
western parts of ND as the weak shortwave comes out of Montana...and
the shortwave over the Red River valley moves east. There seems to
be some disconnect between the upper support and the best
instability...so for now will keep out any mention of severe but
some isolated large hail is not out of the question. Any
convection along the boundary will taper off by late evening.

Tomorrow...a much stronger shortwave trough will begin to dig into
western Minnesota out of Canada. There will be a brief period of westerly
winds...but a stronger cold front will move down into the County Warning Area by
peak heating. There does not seem to be a huge amount of
instability available...with surface based cape of around 1000 j/kg on
the higher end of the models...but forcing with the incoming
shortwave will be very strong. Will have to watch for wind and
hail possibilities tomorrow afternoon. The front will also knock
down temperatures a bit closer to average for this time of year.

Saturday night...the upper trough will move off into the Great
Lakes...leaving the northern plains in northwesterly flow aloft.
The center of the surface high behind the cold front will remain over
the Western Plains and we should have some lingering cloud
cover...so kept lows around 50 degrees.

Long term...(sunday through friday)
issued at 313 PM CDT Friday Sep 19 2014

Sunday and Monday...conditions will be fairly quiet as we
transition from northwesterly flow aloft to a ridge over the
plains. A cut off upper low will remain to our south and west.
Temperatures should see a slight warming trend from the upper 60s
on Sunday into the low 70s on Monday as the surface high moves off to
the southeast and return flow sets up over the region.

Will start off the Monday night through Friday period with 500mb
ridging over the forecast area...but will have a 500mb low cutting through the
ridge over the western High Plains. This low will slowly cross the
northern plains Tuesday through Wednesday night. Therefore will keep Monday night
dry but have some precipitation chances Tuesday through Wednesday night. As the low passes
off to the east will be looking at dry weather again for Thu/Fri.
Temperatures generally look close to normal early on...but become a little
warmer again by Thu/Fri.

&&

Aviation...(for the 00z tafs through 00z Saturday evening)
issued at 651 PM CDT Friday Sep 19 2014

Isolated storms this evening otherwise VFR through the period with
wind switching to the northwest from NW-se.

&&

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

$$

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

National Weather Service Glossary of Abbreviations