Area Forecast Discussion
Issued by NWS Bismarck, ND

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FXUS63 KBIS 220458

Area Forecast Discussion
National Weather Service Bismarck ND
1158 PM CDT SUN AUG 21 2016

Issued at 1158 PM CDT Sun Aug 21 2016

Latest water vapor shows broad mid/upper level ridging across
western and central ND this evening. A minor shortwave was
embedded within a west to southwest flow in eastern Montana. This
shortwave does very little overnight other than suppressing the
height fields through mid morning Monday and providing for very
weak upward vertical motion per Q-vector divergence field. Thus
will continue with a clear sky. Current forecast remains on track.

UPDATE Issued at 928 PM CDT Sun Aug 21 2016

Weak high pressure continues to move south and east as low
pressure develops over the lee of the Canadian and Northern
Rockies. Lowered temperatures a little, especially over our
normally cool spots in the southwest and south central. Otherwise
a clear and quiet night is in store.

UPDATE Issued at 614 PM CDT Sun Aug 21 2016

Weak high pressure will continue to move east out of the forecast
area as low pressure develops in the lee of the Canadian and
Northern rockies tonight. Clear and not as cool tonight with
generally light southerly winds. No significant changes were made
other than updating latest sensible weather elements.


.SHORT TERM...(This evening through Monday)
Issued at 346 PM CDT Sun Aug 21 2016

Currently...large surface high centered over Missouri with a low
centered over southern Alberta with a trough extending south along
the eastern Rockies/Front Range. South/southwest winds were allowing
warm advection with temperatures in the 80s over much of western and
central ND. At upper levels...a western ridge continued to expand
eastward into the western Plains. Meanwhile an upper level
low/trough was over southern British Columbia.

Tonight and Monday the upper level ridge remains and builds over the
Northern Plains as the British Columbia low moves east across the
southern Canadian Rockies. The Alberta surface low and dry surface
trough extending southward from the low moves east tonight. Looking
at low temperatures fairly comfortable in the mid to upper 50s.

The surface trough enters western ND Monday morning and approaches
central ND in the afternoon. This will allow quick warming with
mixing of the low levels to well above 10,000 feet. Looking at high
temperatures in the low to mid 90s over western and most of central
ND with afternoon relative humidities as low as 15 to 20 percent.

.LONG TERM...(Monday night through Sunday)
Issued at 346 PM CDT Sun Aug 21 2016

The upper level Canadian low moves into southern Saskatchewan Monday
night, continuing eastward into the western part of Ontario by
Wednesday evening.

A surface cold front moves southeast across the state Tuesday
morning. Most of the upper level energy for the Tuesday event will
be in southern Canada and along the northern tier of counties in ND.
Thus looking at chances of showers and thunderstorms late Monday
night in the northwest along/ahead of the front, then across mainly
northern ND daytime Tuesday along/behind the front. Gusty northwest
winds of 15 to 25 mph with higher gusts in the southwest will usher
in some cooler air. Looking at highs from the mid 70s northwest to
mid 80s James Valley.

On Wednesday as the upper low moves towards Ontario, a secondary
cold front will drop southward across ND. This will bring cooler,
moist air south across the state. Looking at a mostly cloudy day
with highs in the mid 60s northwest to mid 70s James Valley. Chances
of showers and thunderstorms will be mainly across the northern half
of the state.

The rest of the week will be characterized by northwest flow aloft
becoming more zonal, with another upper low moving into British
Columbia late in the week and building a shortwave ridge over the
Rockies/western Plains. The models depict the BC low becoming more
stationary through next weekend, suggesting periodic changes from
zonal to southwest flow aloft. Basically we can expect a gradual
warming trend Thursday through next weekend, with small chances of
showers or thunderstorms into the weekend.


.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1158 PM CDT Sun Aug 21 2016

Vfr cigs/vsbys next 24hr. A cold front will impinge into KISN/KDIK
between 00z and 06z Tuesday. A vcsh was added to KISN at 01z
Tuesday. Otherwise, KJMS may see a period of showers and
thunderstorms just after 06z Tuesday; dry at all other terminals
through the forecast period.


.BIS Watches/Warnings/Advisories...


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