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Area forecast discussion 
National Weather Service North Platte NE
557 PM CST Wednesday Nov 26 2014

Synopsis...
issued at 318 PM CST Wednesday Nov 26 2014

500 mb analysis from this morning has a closed low over
Nunavut with a trough extending southward into the southeastern Continental U.S.. a couple of
upper level disturbances were noted over Kentucky and northern MO. Strong
winds were noted in the middle levels as a 90+kt 500 mb jet streak extended
from western Montana into southwestern Kansas. At the surface...low pressure was
present over northern MO with a cold front extending south and west of
the low into the Ozarks and Texas Panhandle. Cold air behind the front
has backed to along the front ranges of The Rockies in Colorado and
Wyoming. Looking at the 700 mb thermal field...a decent frontal boundary
extended across the Panhandle and extreme southwestern Nebraska. The
700 mb front...coupled with the 500 mb jet streak...has led to light snow
across the Panhandle and northeastern Colorado this afternoon. Skies
were mostly cloudy across western and north central Nebraska this
afternoon. Temperatures as of middle afternoon ranged from 25 at Oneill
to 34 at North Platte and Ogallala.

&&

Short term...(this evening through thursday)
issued at 318 PM CST Wednesday Nov 26 2014

Low to middle level frontogenetic band currently
across southwest Nebraska is shown by the hires near term models to
become less defined through the afternoon as the atmosphere loses
saturation in the dendritic growth zone. The hrrr seems to be
handling the current situation well...thus the forecast was trended
in that direction with snow ending across our southwest this
evening. The latest hrrr does show another push of lower level
moisture this evening...thus the reason of extending a snow mention
into this evening. Across north central Nebraska this
evening...bufr soundings show deep saturation...which at times
reaches into the dgz...whats missing is deep lift...but there are
indications of at least weak Omega. Previous forecast handled this
potential with --sn...will do the same.

Overnight lows will be chilly...with less mixing in mind overnight
lows should bottom out in the teens across the east...with lower 20s
over the higher terrain of the west.

Tomorrow...a general warming and drying trend is forecast by all
available guidance as surface high pressure builds off to the east and a
Lee trough deepens to the west. Southerly...to westerly flow will
advect warmer 850 mb temperatures across the region...with our far western &
southwestern zones topping 10c by 00z Friday. This should provide
for temperatures in the lower 60s across southwest Nebraska and the
eastern Panhandle. There will remain a sharp gradient of
temperatures as one heads east. Across The Heart of the sandhills
highs in the 40s and 50s should prevail...to the east of
there...across north central Nebraska...highs may struggle to reach
into the middle 30s...owing the presence of persistent stratus and
cooler air recycled from the departing high. Your Thanksgiving
forecast is dry as the tropospheric column is shown to dry on
Thursday.

Long term...(thursday night through wednesday)
issued at 318 PM CST Wednesday Nov 26 2014

Middle Range...Thursday night through Saturday...in the
Middle Range...unseasonably warm and dry conditions are
expected...with the main forecast challenge being high temperatures
for Friday and Saturday. For Thursday night...a warm front will
continue to lift northeast of the area into North Dakota and
Minnesota. A weak surface trough of low pressure will develop across
the High Plains of Nebraska and Kansas overnight leading to light
westerly winds. Overnight lows will be on the mild side for this time of
year with readings around 25 forecast for Friday morning. With light
westerly winds forecast...went with some lower 20s in the Platte
River valley. Friday and Friday night...warm 850 mb temperatures will push
into the region with 850 mb temperatures ranging from 8 to 16c. This will
result in highs well into the 50s to middle 60s Friday afternoon. On
Friday night...lows will be mild with temperatures in the upper 20s
to lower 30s expected. On Saturday...an Arctic cold front will push
into the Dakotas...ending up somewhere in South Dakota by 00z
Sunday. The Euro solution is most aggressive with the front being along
the South Dakota/NE border by this time. The NAM and GFS are slower and have
the front over central and northern South Dakota during 00z Sunday.
Regardless...the front will be north of the forecast area before
peak heating. With the appg front and 850 mb temperatures reaching the middle
to upper teens Sat afternoon...highs will surge into the 60s and may
approach 70 in the southwest. Records for Saturday are in the middle
70s for Valentine and Imperial...and 71 for North Platte and 69 for
Broken Bow respectively.

Long range...Saturday night through Wednesday...a strong Arctic
frontal passage will push through the forecast area Saturday night. Forecast
will continue to be dry behind the front with the best forcing over
North Dakota and northern Minnesota. 850 mb temperatures behind the front Sunday
will range from -13c in the north to -7c in the south. With decent
northerly winds and mixing highs will struggle to get out of the 20s
Sunday. Temperatures will moderate some Monday...with a better
warmup expected on Tuesday and Wednesday. By Wednesday...the
precipitation forecast becomes more of a challenge thanks to split
flow. The latest GFS and European model (ecmwf) have divergent solutions toward the
middle of the week. The GFS is most aggressive...pushing a shortwave
trough across the intermountain west Wednesday...while the European model (ecmwf) has
the trough in northern California. With the model disagreements
at this time...will leave the period dry.



&&

Aviation...(for the 00z tafs through 00z Thursday evening)
issued at 555 PM CST Wednesday Nov 26 2014

The concern to aviation with this forecast package is the
scattered snow showers in western and southwest Nebraska. Ceiling
with the snow is expected to be 1000-3000 feet above ground level with visibility
possible as low as 1sm but generally 3-5sm. The snow in those
areas will dissipate by 08z with improved ceiling and visibility
floolowing. The snow is not likely to have significant impact on
flight ceiling or visibility at vtn or lbf. Ceilings south and
west of kien-lxn will be 7000-12000 feet with visibility at or
above 6sm. In the rest of the area...unlimited ceiling and
visibility will be the rule through Thursday evening.

&&

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

$$

Synopsis...clb
short term...Jacobs
long term...clb
aviation...Springer

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