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Area forecast discussion 
National Weather Service Bismarck ND
1220 am CDT Tuesday Jul 7 2015

Update...
issued at 1221 am CDT Tuesday Jul 7 2015

High pressure was centered over central North Dakota. Light winds
and clear skies expected to continue. The only issue is any smoke
from Canadian fires. Latest observations indicating some 4-5 mile
reports at Dickinson...Glen Ullin...and Hettinger for the past few
hours. Would not be surprised to see visibilities lower at other
sites in western and central North Dakota tonight. Therefore will
keep the mention of smoke in the forecast.

Update issued at 917 PM CDT Monday Jul 6 2015

Clouds continue to dissipate leading to a quiet night. Only issue
will be the lingering areas of smoke. Updates have been sent.

Update issued at 611 PM CDT Monday Jul 6 2015

Quiet weather continues across the area with clouds diminishing
with loss of diurnal heating. Areas of smoke will continue and may
thicken some overnight as winds decrease.

&&

Short term...(this evening through tuesday)
issued at 324 PM CDT Monday Jul 6 2015

The main forecast issue in the short term period will be chances
for convection Tuesday afternoon.

Currently...broken VFR ceiling around 4-7kft across western and
central North Dakota in a northwest flow pattern behind an exiting
upper level trough moving into northern Minnesota. Still a good
portion of the forecast area experiencing 4-8sm visibilities in
smoke.

Late this afternoon...expect clouds to slowly diminish. Have
removed the mention of showers for the remainder of the afternoon.

Tonight...should be a cool and quiet night with lows in the middle
40s to middle 50s. Think smoke may disperse a little through the
evening but once we decouple we should see light and variable
winds through the night as surface high tracks across the state.
Thus will keep a mention of smoke through the night. With light
winds expected through at least the morning hours will continue a
mention of smoke through the day. Later shifts can revisit this
issue if conditions improve.

Tuesday...southerly return flow picks up over western North Dakota
Tuesday afternoon. A northern stream shortwave and another
tracking through the northern/central rockies will induce surface
low pressure over eastern Montana. Weak afternoon instability
combined with middle-upper level forcing could spark a few showers or
thunderstorms Tuesday afternoon. Better warm advection and forcing
arrive in the long term.

Long term...(tuesday night through monday)
issued at 324 PM CDT Monday Jul 6 2015

Gradually warmer through the long term period with highest chances
for Tuesday night through Wednesday...and Saturday into Sunday.
Mainly dry in between those time periods mentioned above.

For Tuesday night through Wednesday night...a cold front will sweep
across southern Canada...and in doing so will extend into western
and central North Dakota through Wednesday. One jet streak is
forecast to lie across southern Canada with a secondary jet streak
scooting across central and southern North Dakota. In both cases the
right entrance region of the jet will enhance vertical motion over
the surface cold front...in combination with a middle level shortwave
trough pushing from west to east Tuesday night into Wednesday. The
jet streak...middle level shortwave...and surface front will support
the chance for showers and thunderstorms through the period. The
forcing from the jet aloft and shortwave trough wanes Wednesday
evening/night with the cold front progressing east. Hence probability of precipitation
decrease and will end overnight. As with the previous discussions
and forecast...cape values remain less than 1000 j/kg with 0-6km
shear of around 35kt...so an isolated strong to severe thunderstorm
possible...but not widespread at this time.

Thursday through Monday...a brief transition to westerly flow
develops Thursday with a transitory middle level ridging migrating
through. This should suppress vertical motion and inhibit the
development of showers/thunderstorms. Cape values forecast to remain
at or below 1000 j/kg with 0-6m shear at 20kt or less Thursday
afternoon. Beginning Thursday night a couple of weak shortwaves
begin to slide into western and central North Dakota. The most
significant middle level shortwave trough/700-500mb...slowly pushes
across northeast Montana Friday night/Saturday...and then scoots
across northern North Dakota Saturday night and Sunday. Should see
an increase in coverage and intensity of showers and thunderstorms
develop Friday night through Sunday timeframe...although
indications are the north would be the favored area in the
proximity of the middle level trough and greatest vertical motion.
Decreasing chances for precipitation south at this time. Upper
level ridging begins to amplify over North Dakota Monday with
drier conditions.

&&

Aviation...(for the 06z tafs through 06z Tuesday night)
issued at 1221 am CDT Tuesday Jul 7 2015

Kdik was reporting 3-5sm in smoke the past few hours. Would not be
surprised to see visibilities at other taf sites to lower with time
beneath the nighttime inversion. Therefore will mention 3-4sm in
smoke for the overnight hours. Put in scattered deck as when smoke
becomes thicker the ASOS reports the smoke as a cloud layer. But no
clouds expected overnight. Expect most locations will improve to
VFR around middle-morning as southerly winds increase. Chance of
thunderstorms begins Tuesday afternoon in the southwest...spreading
north and east across the state Tuesday night. Mentioned thunderstorms in the vicinity at
kdik as chances will begin there early in the afternoon. Too far in
time to mention at other taf sites.

&&

Bis watches/warnings/advisories...
none.
&&

$$

Update...jv
short term...twh
long term...Kansas
aviation...jv

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