Scientific Forecaster Discussion

Return to Local Conditions & Forecast
Area forecast discussion 
National Weather Service Grand Forks ND
330 am CDT sun Apr 20 2014

Short term...(today through monday)
issued at 325 am CDT sun Apr 20 2014

Forecast challenge concerns mainly temperatures and rain chances.
Models in fair agreement and will use blend.

Surface high pressure will shift east today setting up modest
return flow. Thermal ridge will cross forecast area this afternoon just ahead
of next surface boundary associated with short wave which will be
tracking along international border. With a good deal of solar
will likely see temperatures bump up quite a bit above average.

For tonight surface low and short wave will take a similar track
as system a few days ago. Surface low not nearly as deep and
precipitable water values are around .70 inches vs nearly an inch
with previous system which produced .10-.20 quantitative precipitation forecast. With less
available moisture and best lift north of the border feel any precipitation
will be pretty spotty and will keep probability of precipitation low. With boundary
passage cold advection spreads across the region however after
warm day not sure how far temperatures will drop so will stick
pretty close to current values.

Monday will be cooler with colder column and cloud cover. Some
light precipitation possible in wrap around across the far north.

Long term...(monday night through saturday)
issued at 325 am CDT sun Apr 20 2014

High pressure builds in Monday night and will see temperatures
much closer to average with northern areas seeing temperatures dip
below freezing.

Temperatures should be able to recover to at or a little above
average on Tuesday as high shifts east and mixing and warm
advection increases.

Surface low pressure will organize and begin to shift east Tuesday
night. Precipitable water values/low level warm advection increases
overnight and as low level jet becomes established could see some
precipitation working into the forecast area. Made some minor adjustments to timing
this period but did not increase probability of precipitation at this point and help any
precipitation to along and west of the valley.

Wednesday to Saturday night...models in good agreement with 500mb
cutoff low to cross the northern plains and bring a round or two of
precipitation. How the 500mb cutoff evolves has been much less consistent
but the general pattern has been well prognosticated. The first round of
precipitation enters Wednesday afternoon with 850-700mb warm air advection underneath 500mb
divergence that should bring a band of showers and possibly thunder
across the Dakotas into northwest Minnesota. Thursday 500mb cold core causes up to
400j/kg of cape in the 00z European model (ecmwf) across east ND. As the north winds on
the backside advect in a subfreezing blyr a few snow showers are
possible to mix into the precipitation Friday morning across NE ND and into
northwest Minnesota. Near normal for maximum temperatures Wednesday and Thursday with below late April
normals for the weekend.

&&

Aviation...(for the 06z tafs through 06z Sunday night)
issued at 142 PM CDT Sat Apr 19 2014

Good flying weather Easter Sunday. Light and variable winds and
clear sky at sunrise will give way to south winds 8 to 15 kts
midday and 10-20 kts in the afternoon. Some cirrus to move in from the
west in the afternoon ahead of cold front with some middle clouds in the
evening into eastern ND ahead of front. Front looks to arrive in dvl near 03z
and gfk area 06z Monday with wind shift to the northwest. Precipitation
chances look pretty low.



&&

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

$$

Short term...voelker
long term...jk/voelker
aviation...Riddle