Area forecast discussion
National Weather Service Bismarck ND
318 PM CDT Wednesday may 22 2013
Short term...(this evening through thursday)
issued at 317 PM CDT Wednesday may 22 2013
The highlight of the short term is strong winds across southwest
North Dakota on Thursday.
For tonight...left out the mention of fog despite the recent
rainfall as east-northeast winds of 5-10 kts through the night
should provide sufficient mixing to hold off fog formation. This is
confirmed by the 19 UTC lamp guidance and 15 UTC sref visibility
probabilistic forecasts.
For Thursday...deepening low pressure across Wyoming and Montana
and a resulting tight pressure gradient across western and central
North Dakota is expected to yield a windy day across the area. The
strongest winds are expected to be across the southwest where
gradient winds are greatest...with 40-45 kts to mix at the base
of an inversion at 800 mb formed by a low level warm air advection
regime in southeasterly flow. This wind direction does limit
mixing heights...and thus the potential for 50+ kts within the
inversion to be mixed to the surface. Have thus issued a Wind
Advisory for southwest North Dakota from 15-03 UTC.
Otherwise...for the remainder of the forecast fields a blend of
the 12 UTC deterministic and statistical guidance suite was used
given good agreement.
Long term...(thursday night through wednesday)
issued at 317 PM CDT Wednesday may 22 2013
Dry conditions are expected Thursday night as middle/upper level
ridging continues over the plains. However...the large upper level
low over the Pacific northwest/rockies will expand...and Friday will
begin the prolonged period of southwest flow aloft over the
state.
The medium range models forecast the first impulse to eject from of the
aforementioned Pacific northwest/rockies low over western and
central North Dakota Friday. This will lead to thunderstorm chances
developing area-wide on Friday...with the unsettled weather pattern
continuing through the end of the long term period.
The persistent southwesterly flow aloft combined with Gulf of Mexico
moisture tap will lead to chances for thunderstorms each day this
weekend through the first part of next week. The persistent return
flow should also allow for a gradual warming trend to develop
Saturday and continue through the end of the period. Look for highs
in the 60s central and 70s west Friday through the weekend. By
Memorial Day...highs should generally be in the 70s over all of
western and central North Dakota.
&&
Aviation...(for the 18z tafs through 18z Thursday afternoon)
issued at 317 PM CDT Wednesday may 22 2013
VFR conditions are forecast for the 18 UTC taf cycle across
western and central North Dakota. Despite recent rainfall...east-
northeast winds should be strong enough to prevent fog formation
across the area tonight. Otherwise...for Wednesday...strong
southeast winds are expected ahead of low pressure across
Montana. Gusts to 35 kts are possible at kdik...25-30 kts at
kisn...kmot and kbis...and 20-25 kts at kjms.
&&
Hydrology...
issued at 317 PM CDT Wednesday may 22 2013
Lake Darling is expected to increase releases to 1000 cfs Thursday
morning. This will cause the Souris river at Foxholm to rise above
minor flood stage. Otherwise...will continue to watch the
Willow Creek near Willow City as a possible rise above flood stage
is forecast by Thursday night. Some uncertainty remains in how
much water will arrive in The Channel from recent rainfall.
Finally...did cancel the Flood Warning for the Pipestem creek near
Pingree as runoff has turned out to be lower than previously
forecast.
&&
Bis watches/warnings/advisories...
Wind Advisory from 10 am CDT /9 am MDT/ to 10 PM CDT /9 PM MDT/
Thursday for ndz017-018-031>033-040-041-043-044.
&&
$$
Short term...ayd
long term...jv
aviation...ayd
hydrology...ayd
