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National Weather Service North Platte NE
625 am CDT Friday Jul 3 2015

Update...
issued at 625 am CDT Friday Jul 3 2015

Updated forecast for dense fog advisory for north central
Nebraska. Have updated sky grids and expanded fog forecast.
Visibilities have been reduced to a quarter of a mile over a large
area.

&&

Short term...(today and tonight)
issued at 334 am CDT Friday Jul 3 2015

Areas of fog developing over north central Nebraska early this
morning along an inverted trough axis. Abundant deep layer moisture
to around 700mb 90 percent relative humidity. Have retained fog from Valentine to
North Platte and east. Looks to burn off around 16 to 17z. General
cloudiness expected around the trough axis through the day with
differential heating and good low level moisture...dew points in the middle
60s...and trough axis for focus can't rule out an afternoon
thunderstorm. Have retained schc probability of precipitation through the afternoon. Showers
and thunderstorms over the eastern plains of Wyoming and Colorado
with upper jet dynamics should remain to the southwest of forecast
area and have silent probability of precipitation going for now. May have to be reassessed in
later forecasts. Highs today in the low to middle 8os. Mostly clear
tonight will lows around 60.

Long term...(saturday through thursday)
issued at 334 am CDT Friday Jul 3 2015

Saturday through Sunday night...return flow will be underway
Saturday morning and continue through Sunday afternoon. Dew points
will rise into the upper 60s to near 70 along and east of Highway 83
by Sunday.

Low pressure on the northern High Plains Saturday will aim the warmest
air across western Nebraska with highs in the lower 90s. East...south winds
and return moisture should limit mixing with 80s for highs. The surface
low will drop due south into the cntl High Plains Sunday and this
will likely cause surface winds to back in the east while northeast
winds develop north of the surface low across northwest Nebraska.

The formation of an inverted trough/nearly stationary front will be
the focus for heavy thunderstorms Sunday night. Storm development
could be underway Sunday afternoon north of the front. The GFS and
NAM soundings show a middle level dry slot in the afternoon which could
support wind damage especially north. Windex values in the 70s are
shown north and south with ambient precipitable water of 1.50+ inches suggesting
the potential for wet microburst. Hail potential seems less of a
threat given the modest shear and high freezing levels. Storm Prediction Center has
outlooked ncntl Nebraska for severe weather Sunday.

The NAM and GFS soundings suggests dry middle level air and a modest
cap which could limit rain chances across southwestern Nebraska Sunday night.
Northeast...no cap and deep moisture should support widespread
thunderstorm development. The right rear quadrant of a 300 mb jet
will be operating to send a cold front into western Nebraska Sunday night.
Quantitative precipitation forecast plumes suggest from 1/2 inch of rain southwest to 1 or 2 inches
in the northeast.

There is isolated thunderstorm potential late Saturday afternoon... evening and
overnight across all of western and north cntl Nebraska. The models show a
60kt 300 mb jet streak across Wyoming which digs a 700mb trough Lee of
The Rockies for support. The 700mb trough and associated warm air
advection move slowly east through the forecast area overnight. Storm Prediction Center
suggested a marginal severe risk across western Nebraska if storms can
develop during or close to the peak heating period.

The Sunday temperature forecast is somewhat uncertain and hinges on
the location of the inverted trough which will set up strong warm air
advection across southwestern Nebraska while cooling the northwest behind a
stationary front and moistening up areas across the northeast. 80s
to lower 90s are in place which could perhaps rise to middle 90s.

Monday through Thursday...the upper level ridge which baked the western
U.S. For days retreats into the Desert Southwest and then builds
flatly across the middle south setting up a zonal flow aloft with an
upper level low off the California coast. It is believed a plume of
subtropical upper level moisture will traverse Nebraska Tuesday night
through Thursday. Upper level disturbances will be moving through
the cntl and Southern Plains supporting thunderstorms during this time.
The GFS and ecm show another inverted surface trough setting up across the
forecast area Wednesday for focus. Probability of precipitation are 40 percent for this event as
the GFS and ecm show scattered probability of precipitation and quantitative precipitation forecast. The GFS ensemble
suggested rain would be more likely across Kansas and okla where the southern
disturbance will be tracking.

Highs in the 70s and 80s are expected Monday through Thursday given
the substantial batch of Canadian high pressure moving in Monday
which should last through Wednesday.

&&

Aviation...(for the 12z tafs through 12z Saturday morning)
issued at 625 am CDT Friday Jul 3 2015

Stratus over north central Nebraska between kanw, kbbw and konl
early this morning reducing visibilities to less than a quarter of
a mile. This will improve slowly through late morning. Over the
remainder of western Nebraska skies will be mostly clear with some
convective development this afternoon. Winds light and variable.

&&

Lbf watches/warnings/advisories...
dense fog advisory until 10 am CDT this morning for nez006>010-
026>029-038.

&&

$$

Update...power
short term...power
long term...cdc
aviation...power

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