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Area forecast discussion 
National Weather Service Grand Forks ND
639 am CDT Friday Jul 25 2014

Update...
issued at 638 am CDT Friday Jul 25 2014

Most of the precipitation has dissipated as the low level jet has shifted
off to the east and has been feeding the convective complex
further south over Minnesota. A few showers have tried to redevelop
further north and west...and there is still the trough axis that
is due to move through today. Will continue to keep 20-30 probability of precipitation
east of the wind shift.

&&

Short term...(today through saturday)
issued at 302 am CDT Friday Jul 25 2014

Convection chances throughout the period will be the main forecast
problem for the short term.

The main upper low remains over southern Alberta but a few weak
shortwave troughs have moved into the northern plains overnight.
The northern shortwave has been producing storms over western ND
and some of the activity has been moving into our northwestern County Warning Area
and weakening. The southern shortwave has interacted with some
strong elevated instability and the low level jet to set off some
storms over eastern South Dakota and far southeastern ND. The storms were
just under severe limits at times but have weakened in the past
few hours. As the low level jet nose moves off to the east...think
that the activity over our southern counties will gradually
weaken.

Today...the surface low currently over South Dakota will weaken and move
east...pushing a weak boundary/wind shift across the County Warning Area. Timing
of the system will be key...and it is possible that there could be
some cape values of 2000 j/kg ahead of the boundary. The question
will be if the cap can be overcome with most of the best forcing
off to the east. The boundary may also be past our counties before
peak heating. Will continue to keep some 20-40 probability of precipitation going mainly
over our eastern counties...but will leave out any mention of
strength for now.

The upper low over Saskatchewan will continue to move slowly southeastward
tonight...dropping into the northern County Warning Area by tomorrow. Surface low
pressure will redevelop over southern Canada and move east...this
time dropping a pretty substantial cold front into the area. Temperatures
will be tricky for Saturday but for now went low 70s in the north
to low 80s in the southeast. Models mainly have precipitation moving in
along the frontal boundary into our northern counties in the
afternoon...which seems reasonable. Instability will be pretty
weak...under 1000 j/kg so severe threat is not impressive.

Long term...(saturday night through thursday)
issued at 302 am CDT Friday Jul 25 2014

Saturday night through Sunday night...cold air advection behind a
cold front will continue through Saturday night. High pressure
will build into the northern plains through Sunday and Sunday
night. Even with the surface high...with the upper low in the area
there could still be some shower and thunderstorm development with
daytime heating...particularly in the east where middle level temperatures
will be the lowest. Sunday should be cool with temperatures well below
seasonal averages and lows Sunday night should drop in the low to
middle 50s.

Monday-Thursday...northwest flow aloft will remain in place through
the period...with surface high pressure providing tranquil conditions to
start the week. A very gradual increase in temperatures is expected through
middle-week to near average. Much of the period should be dry...with any
low middle-week precipitation chances dependent on low predictability low
amplitude short wave troughs riding over the western US ridge.

&&

Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 638 am CDT Friday Jul 25 2014

Middle and high clouds will bring VFR conditions throughout the
period. Light southeast winds will shift to the west as a trough
of low pressure moves through the area.

&&

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

$$

Update...Jr
short term...Jr
long term...Jr/makowski
aviation...Jr

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