Area Forecast Discussion
Issued by NWS Bismarck, ND

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593
FXUS63 KBIS 251733
AFDBIS

Area Forecast Discussion
National Weather Service Bismarck ND
1233 PM CDT Tue Jul 25 2017

.UPDATE...
Issued at 1142 AM CDT Tue Jul 25 2017

No major changes were needed with this update. Just tweaked
precipitation chances to reflect the most current radar trends and
the latest high resolution guidance. Otherwise, blended the latest
observations to the going forecast.

UPDATE Issued at 649 AM CDT Tue Jul 25 2017

Main adjustments to the forecast surrounded rain chances this
morning. Early morning radar shows showers and a few thunderstorms
moving through western and central North Dakota. In general, the
thunderstorms have been well below severe limits early this
morning, though the storms in Grant county have shown some signs
of brief strengthening in the past hour. The latest meso-analysis
suggests a little more instability for the storms to work with as
they move northeast with MUCAPE around 1000 j/kg. Have increased
pops some in the south based on latest trends and short term
model solutions.

&&

.SHORT TERM...(Today and tonight)
Issued at 303 AM CDT Tue Jul 25 2017

Isolated to scattered showers along with isolated thunderstorms
is the weather highlight today. Highest chances for precipitation
is along and south of Interstate 94, with lower chances for
portions of the north this morning.

Latest water vapor imagery shows a zonal flow across western/central
North Dakota. Surface map shows a cold front from near Rolla,
southwest to Hazen, to Lemmon South Dakota. The cold front will
continue to push southeast early this morning, moving through
Bismarck/Mandan 09z-12z, and through the southern James River
Valley by 15z today. Instability continues this morning along and
south of the front, and shrinks through the morning, mainly
occupying a small area in the southern James River Valley this
afternoon. This is where SPC has the Marginal Severe Risk.

Upstream, a couple of mid/upper level shortwaves in eastern Montana
will shift across southern ND through early afternoon. SPC
mesoanalysis 925-850mb frontogenesis/forcing lines up well where
we have the radar returns. Bowman and regional radar indicate
areas of showers and isolated thunderstorms with these shortwaves.
The high resolution models as well as the operational NAM/GFS
show these areas of showers and isolated thunderstorms percolating
from time to time through 21z, with the highest pops along and
south of Interstate 94. High temperatures will be a bit tricky in
the above mentioned area, due to varying cloud cover and
precipitation. Highs overall will not be as hot, with low to mid
80s expected.

For tonight, dry weather with the last of the showers exiting the
far southern James River Valley in the evening. Overnight lows
will range from the mid 50s north to lower 60s far south central.

.LONG TERM...(Wednesday through Monday)
Issued at 303 AM CDT Tue Jul 25 2017

Dry and warm weather Wednesday and Thursday with highs in the mid
to upper 80s. Chances for showers and thunderstorms return west
into central Friday through Saturday as a mid level shortwave
trough slides. Cape and Shear generally remain marginal for any
severe threat during this time period. Heights rise Sunday and
Monday resulting in mostly dry weather and highs in the 80s to
around 90.

&&

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1142 AM CDT Tue Jul 25 2017

VFR conditions expected at all TAF sites. Showers may extend and
persist at KBIS/KJMS into early afternoon, and for now have opted
to mention a VCTS/VCSH. The threat for showers and thunderstorms
diminishes quickly this evening with gradual clearing Tuesday
night.

&&

.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...ZH
SHORT TERM...KS
LONG TERM...KS
AVIATION...AJ



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