Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

fxus63 kbis 240534 

Area forecast discussion
National Weather Service Bismarck ND
1234 am CDT Tue Oct 24 2017

issued at 1233 am CDT Tue Oct 24 2017

Northwest winds remain at 10 to 15 mph over most areas early this
morning. Cold advection continues this morning, with temperatures
already in the lower 30s in some locales of southwestern North
Dakota. Current forecast on track and no big changes in the forecast
for the overnight hours.

Update issued at 927 PM CDT Mon Oct 23 2017

Winds have tapered off a bit quicker than previously forecast, and
skies have cleared out over most locations. Have addressed these
concerns with latest update.

Update issued at 720 PM CDT Mon Oct 23 2017

Wind Advisory has been allowed to expire as winds continue to
slowly taper off, though will remain gusty going through the
evening. Light precipitation over the south will also continue to
taper off over the next hour or so. Updates have been sent.


Short term...(this evening through tuesday)
issued at 308 PM CDT Mon Oct 23 2017

Strong pressure gradient remains over western and central ND.
Several observation are currently gusting 40 to 50 mph. Will
continue the Wind Advisory.

With daytime heating, and a weak impulse dropping south through
central ND, scattered convective showers have developed over the
area. Will add a few sprinkles to the forecast this afternoon and
early this evening.

Winds diminish and sky clears tonight. Winds don't drop off
completely, so don't expect a real cold night, but did lean a bit
toward cooler guidance in our normally cool areas in the west.

Long term...(tuesday night through monday)
issued at 308 PM CDT Mon Oct 23 2017

The main forecast issue in the long term period will be fire
weather issues on Wednesday, then much colder temperatures and a
chance of rain and snow Wednesday night and Thursday.

A strong eastern Pacific Ridge and central and eastern U.S trough
pattern maintains itself through the long term period. A couple
clipper type systems tracking through the ridge trough pattern
will be responsible for or weather.

After a relatively quiet Tuesday, an impulse over Canada will
induce a surface low over western Canada and propagate into
western North Dakota by 00 UTC Thursday. This will produce a mild
west to southwest flow over the area Wednesday with high climbing
well into the 60s. The low then tracks across the forecast area
Wednesday night, bringing strong cold advection in it's wake. Mid
level forcing will also traverse the area Wednesday night,
associated with the shortwave trough.

There remains some disagreement in the deterministic model
solution, but the one thing we and count on is strong winds due to
a strong pressure gradient, strong cold advection and a
substantial pressure fall-rise couplet traversing the forecast
area. We will likely need some type of highlight for winds
Wednesday night into Thursday.

Quantitative precipitation forecast with this system is limited with the European model (ecmwf) the only model
showing more than minimal liquid. However, models continue to
bounce around with their track of the surface low and this may
change. For now a blend of model solutions places minimal snowfall
amounts over eastern portions of central ND. Higher totals are
farther north and east over southern Manitoba into the northern
Great Lakes.

Much colder air Thursday and Friday with highs mainly in the 30s
and lower 40s, with lows in the mid teens to mid 20s.

Dry with a warming trend Saturday into Sunday, then another
clipper system Sunday night into Monday with a shot of rain and
snow with much colder temperatures into the beginning of next


Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1233 am CDT Tue Oct 24 2017

VFR conditions are expected. Hazards to aviation include low level wind shear
at all taf sites.

A fast moving weather pattern will bring a warm frontal passage this
afternoon as westerly downslope winds across Montana will make there
way into North Dakota. Strong winds aloft will initiate some low
level wind shear beginning late this afternoon and continuing


Fire weather...
issued at 308 PM CDT Mon Oct 23 2017

On Wednesday we are expecting mild temperatures in the 60s with
minimum humidities of 15 to 20 percent over southwest North
Dakota. Increasing winds Wednesday afternoon and early evening
into the 15 to 25 mph range will produce a period of critical fire
weather conditions Wednesday afternoon and early Wednesday
evening. Even stronger winds are expected overnight Wednesday but
humidities are expected to increase during the evening behind the
cold front.


Bis watches/warnings/advisories...
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for ndz031>033-040-041-043-044.



National Weather Service Glossary of Abbreviations