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Area forecast discussion 
National Weather Service North Platte NE
247 PM CDT Monday Aug 31 2015

Synopsis...
issued at 245 PM CDT Monday Aug 31 2015

500 mb hand analysis from this morning had a closed low over southeastern
Alaska with a broad trough of low pressure extending southeastward into
British Columbia. A shortwave...which has broken off from the main
Pacific trough...was lifting across southern Saskatchewan with 100
meter falls noted at Glasgow Montana this morning. A 50 knots jet streak
extended from eastern Montana into ND and far southern Manitoba this
morning. This wave is moving into a well established ridge which
extended from the northern Great Lakes into northern Canada. Across the
remainder of the lower 48...a positively tilted ridge extended
from the desert SW into the middle and upper Mississippi Valley.
Further east...a trough of low pressure was located across the
Ozarks into deep south Texas. Strong shortwaves in association
with the trough were located over southwestern Arkansas and far southern Texas. At
the surface...a weak frontal boundary extended from southwestern Nebraska
around Imperial to north central Nebraska just west of Oneill.
Under mostly cloudy skies in the west and clear skies in the
east...2 PM CDT temperatures ranged from 83 Valentine to 92 at
Imperial.

&&

Short term...(this evening through tuesday)
issued at 245 PM CDT Monday Aug 31 2015

A surface front will remain nearly stationary from near anw
through Imperial tonight. Weak radar returns currently continue
from west of Valentine through the Sidney area. Little if any
precipitation reaching the ground however. A weak upper level
disturbance just emerging onto the Denver Front Range will track
northeast and increase probability of precipitation and areal coverage to 20-30 percent
this evening from southwestern nebr into the central portions of nctrl
nebr along with an increasing low level jet. Only a slight chance
after midnight along the Highway 83 east to near Oneill and Burwell as
low level jet influence diminishes.

The surface front washes out Tuesday with only a weak upper level
disturbance to provide a slight chance for showers or a few
thunderstorms east of North Platte thorugh Ainsworth. With front
washing out...highs will again reach the lower 90s west to upper
80s central and east.



Long term...(tuesday night through monday)
issued at 245 PM CDT Monday Aug 31 2015

Tuesday night through Thursday...temperatures will be the main
forecast concern over the Middle Range...along with any minute chances
for isolated thunderstorms Wednesday/Thursday. For Tuesday
night...inherited forecast had a slight chance mention for thunderstorms
in the southern and eastern County Warning Area. This was contingent on a stalled out
frontal boundary which was expected to remain in place until
Wednesday. The latest forecast solutions have washed this boundary
out Tuesday night. Favorable middle level warm air advection will pass through the
eastern County Warning Area by middle evening...exiting the forecast area by 06z
Wednesday. With this in mind...decided to cut probability of precipitation out of the forecast
after midnight Tuesday night. However...I did go ahead and keep a
slight chance mention in the eastern zones Tuesday evening as favorable middle
level warm air advection does not move east of the area until after middle evening.
Shifting to Wednesday through Thursday...upper level low pressure will
lift into British Columbia...into Alberta Wednesday and Wednesday night. This
will allow the pattern to re-amplify across the central Continental U.S. With
rising 500 mb heights Wednesday into Thursday. A nice thermal ridge will build
into the High Plains with 850 mb temperatures approaching 30c in the Panhandle
both Wednesday and thus afternoon. This will lead to highs well into the lower
to middle 90s...with the possibility of readings appg 100 degrees in
the far west. Surface dew points will fall off into the 40s and lower
50s as the bulk of low level moisture becomes focused across far eastern
Nebraska and eastern South Dakota. This will lead to minimum relative humidity/S of 15 to 20
percent in the Panhandle and western sandhills both days. At this time the
only aspect which may preclude critical fire danger is slightly
diminished winds in the Panhandle and western County Warning Area if a surface
trough remains anchored across these areas. Will be mentioning the
fire danger threat for Wednesday and thus in the afternoon release of the
severe weather potential statement.

Friday through Monday...on Friday...the surface trough will push
east into western Nebraska...allowing the thermal ridge to build into
central and eastern Nebraska...with highs reaching well into the
90s. Winds on Friday east of the trough will be stronger as well as
low pressure in association with the trough...deepens over South
Dakota. Another extreme to critical fire danger day appears likely
once again...albeit...further east than Wednesday and thursdays threat.
Will be mentioning this as well in the afternoon severe weather potential statement. On Saturday
another strong trough of low pressure aloft will push east of the
Pacific northwest...entering Montana and Idaho. This will force the low level
thermal ridge further east with the hottest temperatures across the far
eastern County Warning Area. Highs could eclipse the lower 90s in the east as a
surface trough is expected to set up across the central County Warning Area. With
temperatures in the lower to middle 90s expected in the east...fire danger
would be a concern...however...dew points will be in the lower to
middle 50s in these areas...so min relative humidity will be well above critical
thresholds. On Sunday...the upper level trough will push into the
northern rockies...forcing the prefrontal surface trough just to the
south and southeast of the forecast area. Temperatures will be
warm...albeit not the 90s we are expecting over the next several
days. On Sunday night...the upper level trough will push into the
Dakotas...forcing a strong cold front through the County Warning Area. Along with a
decent threat for precipitation...much cooler temperatures will arrive behind the
front on Monday. After highs in the 80s Sunday...highs will struggle
to get out of the lower to middle 70s for Monday. With respect to precipitation
chances in the extended. The latest GFS solution continues to indicate
increased middle level forcing toward the end of the week in advance of
the appg upper level trough. With a surface trough expected to be
anchored across the central and eastern County Warning Area Friday into
Saturday...did not feel any reason to cut probability of precipitation from the inherited
forecast.

&&

Aviation...(for the 18z tafs through 18z tuesday) issued at 245 PM
CDT Monday Aug 31 2015

A cool front will stall out along a line from koga to kanw this
evening with isolated thunderstorms developing along the line and
spreading slowly east through the night. With isolated nature of
storms have just carried thunderstorms in the vicinity at both kvtn and klbf.

&&

Lbf watches/warnings/advisories...
none.
&&

$$

Synopsis...clb
short term...roberg
long term...clb
aviation...roberg

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