Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Grand Forks ND
943 PM CDT Sat may 23 2015

Update...
issued at 943 PM CDT Sat may 23 2015

Adjusted the clouds a bit more as cirrus and even some middle level
clouds continue to move in from the south. Will continue to keep
lows in the 40s to low 50s.

Update issued at 648 PM CDT Sat may 23 2015

Made a few minor tweaks to clouds to fit current satellite trends
but no changes otherwise to the going forecast.

&&

Short term...(this evening through Sunday night)
issued at 323 PM CDT Sat may 23 2015

Main trend is slower...and modified the pop/weather forecast
accordingly. Anticipate increasing clouds tonight which should
keep the temperatures from dropping too much (except possibly near
the international border). Upper ridging hangs on into Sunday
(even Sunday night) which will keep most areas dry until Sunday
night. Did keep scattered showers on Sunday along and south of
I-94...but even this might be overkill.

Long term...(monday through saturday)
issued at 323 PM CDT Sat may 23 2015

Monday-Tuesday...focus will be on an upper level wave that is
currently rounding the base of The Rockies upper low. This feature
will propagate northward Sunday night with a strong middle-level low
developing. The NAM/sref indicate more interaction with The
Rockies upper low than the ECMWF/GFS. This will affect location of
the heavier rain amounts. At any rate...anticipate a heavier
deformation rain band to set up somewhere across the forecast area (nam/sref
further north than the ECMWF/gfs). With precipitable waters 1.25 to 1.50
inches and strong forcing...operational models and ensemble
guidance all suggest an area of 1-2 inches rainfall...with
isolated amounts up to 4 inches (much like last weekend). We have
had a week to dry out...and this rainfall expected to occur over a
12-24 hour duration...so areal flooding only a minor concern.

Drier on Tuesday...with possible weak afternoon convection.

Tuesday night-Saturday...region will be on southern edge of broad
cyclonic flow over Canada. Initially weak surface boundary across
S mb into Ontario will sag slowly south. Airmass modestly warm and
unstable south of boundary so low probability of precipitation seem reasonable. More
significant surface low associated with another western trough
will track across the Central Plains midweek with the favored precipitation
chances across the southern 2/3rds of the forecast area. Surface high
dropping south out of Canada will shunt main precipitation chances south of
the forecast area towards end of work week but will also bring cooler air
into the region. Temperatures initially will range above average
dropping to at or below averages by end week.

&&

Aviation...(for the 00z tafs through 00z Sunday evening)
issued at 648 PM CDT Sat may 23 2015

Some cirrus moving in and cumulus over the northern forecast area
should dissipate in the next few hours. Some lower clouds will
start moving into the kfar area by morning and the northern taf
sites by afternoon...but conditions will remain VFR with ceilings near
5000 feet. Winds will become light and variable tonight and then
steady out of the east by tomorrow at around 8 to 10 kts



&&

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

$$

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

National Weather Service Glossary of Abbreviations