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fxus63 kbis 171227 

Area forecast discussion
National Weather Service Bismarck ND
627 am CST sun Nov 17 2019

issued at 616 am CST sun Nov 17 2019

We added a small area of fog along the western fringe of the low
stratus over western ND, including Williston through 15 UTC. At
Williston fog developed at the Airport as the clouds receded.
Otherwise no changes to the current forecast.


Short term...(today and tonight)
issued at 304 am CST sun Nov 17 2019

Clouds today and a chance of mixed precipitation tonight will be
the main forecast concerns in the short term period.

Currently, low pressure was moving east from southern Manitoba
into Ontario, with high pressure building over western and central
North Dakota. Widespread MVFR to IFR stratus remains over all but
the far southwest portion of the forecast area.

As upper level ridging and surface high pressure moves east
across the area today, the low stratus will exit to the east and
another impulse moving through the northwest upper flow will bring
a chance of precipitation to the area, beginning this afternoon
in the west and spreading across the forecast area tonight.

Expect a mild day today with a southwest surface flow. Expect
forecast highs from the mid 30s Turtle Mountains to the upper 40s
southwest, with a few 50 degree readings not out of the question
in the far southwest.

This afternoon and tonight, a surface low will track well north of
the forecast area. We will be in the warm sector with upper level
jet energy and strong warm advection providing the ascent for
light precipitation. With mild temperatures, thinking the
precipitation will mostly, fall as liquid. At this time, the only
area of some concern is The Turtle mountains into the northern
James River Valley, where temperatures may fall into the lower
30s, thus introducing the potential for a light wintry mix of
freezing rain, sleet and snow. Quantitative precipitation forecast amounts are very light and
think impacts will be minimal.

Long term...(monday through saturday)
issued at 304 am CST sun Nov 17 2019

Seasonable to mild temperatures and a couple chances of light
precipitation highlight the long term forecast.

On Monday the surface trough pushes to the east with northwest
winds encompassing the forecast area. But another shortwave and
strong upper jet also traverse the forecast area, keeping a small
chance of rain showers through the morning west and into the
afternoon central. Again, qpf will be light and except for a
possible mix very early from The Turtle mountains into the
northern James River Valley, precip should be light rain. Monday
will also be mild with temperatures mainly in the mid 40s to
lower 50s.

Quiet Monday night into Tuesday morning, before the next wave
brings a precipitation across the forecast area late Tuesday
afternoon through Wednesday. Deterministic models have come into
better agreement with this system, bringing the heaviest moisture
to the northern half of the state. Still some details to be ironed
out before then but at this time it looks like precipitation will
begin as rain Tuesday afternoon, the transition to snow Tuesday
evening. The threat for mixed precipitation initially looks low.
However, as the initial wave weakens and exits to the east, we
remain within a mean upper level trough. Thus late Tuesday night
through Wednesday morning, we lose ice aloft with the initial wave
but weak synoptic scale forcing remains over the forecast area,
thus we could see a period of light drizzle or freezing drizzle on
the back side of the system, before precipitation ends by
Wednesday afternoon.

Right now it looks like some light accumulations are possible.
There is some potential for mesoscale banding with based on the
motion of the system. The forcing within the dendritic growth zone
at this time is not all that impressive and is around 10-15k ft
with a warm profile beneath, which could limit accumulations if
banding were to occur.

We see a quick cooldown Wednesday through Thursday, with
temperatures, especially north, struggling to climb above
freezing. We then enter a quasi-zonal upper flow Friday into the
weekend with seasonable temperatures and little if any


Aviation...(for the 12z tafs through 12z Monday morning)
issued at 616 am CST sun Nov 17 2019

LIFR cig/vsby in dense fog at Williston to begin the taf period.
Fog quickly formed as clouds exited the Williston Airport. Kept
dense fog through 14z, improving to VFR by 15 UTC.

Elsewhere clear at kdik to begin the taf period. MVFR cigs at kbis
and kjms and IFR cigs at kmot. Widespread MVFR-IFR ceilings over
central ND will erode from west to east during the day, improving
to VFR around midday at kbis and kmot and mid afternoon kjms.

A quick moving system will bring increasing clouds from west to
east across the forecast area late this afternoon and tonight.
Expect low VFR ceilings with vcsh at taf sites tonight. Ceilings
lower to MVFR toward the end of the forecast period.


Bis watches/warnings/advisories...


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