Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 220439 AAB
AFDLBF

Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
1139 PM CDT THU JUL 21 2016

.SYNOPSIS...
Issued at 337 PM CDT Thu Jul 21 2016

High pressure aloft continues to remain the dominant
weather feature across the lower 48 this morning. This feature was
centered over eastern Oklahoma and extended as far west as the swrn
CONUS and as far east as Georgia. On the periphery of the high,
several shortwaves were noted-the first over northern Nebraska, a
second over Utah, and a third over northern Mexico south of El Paso.
North of the high, low amplitude flow extended from the Pacific
northwest into southern Canada and east toward New England and the
Canadian Maritimes. Within this flow, shortwaves were noted over
western Ontario, northern Minnesota, and off the coast of Washington
state. At the surface, low pressure was located over southeastern
South Dakota with a surface trough extending south southwest from
this feature into central Nebraska and western Kansas. West
southwest of the low, a weak cool front extended along the Nebr/SD
border into northeastern Wyoming. Temperatures north of the front
were cooler today with readings in the lower 90s over western South
Dakota. South of the front, temperatures were in the mid to upper
90s with the exception of portions of central Nebraska, where some
cloud cover this morning has inhibited the warmup somewhat and held
temps in the mid to upper 80s.

&&

.SHORT TERM...(This evening through Friday)
Issued at 337 PM CDT Thu Jul 21 2016

Upper level ridge of high pressure continues to slowly retrograde
west across the southern plains. A subtropical plume of mid and
upper level moisture continues to move northward through the desert
southwest on the western periphery of the ridge. This moisture then
turns east across southern south Dakota, Nebraska and norther
Kansas. The result has been some isolated high based thunderstorms.
These will continue to be possible tonight, but hard to pinpoint
exactly where. Overall the coverage will be isolated. Perhaps a bit
better chance of storms Friday afternoon as a weak wave approaches
within the plume aloft.

Otherwise it continues to be hot and humid, with perhaps more
humidity Friday afternoon as moisture/dew points pool north of a
weak front that will extend along the Nebraska Kansas border.

.LONG TERM...(Friday night through Thursday)
Issued at 337 PM CDT Thu Jul 21 2016

In the mid range, from Friday night through Saturday
night, thunderstorm chances Friday night into Saturday, as well as
frontal timing and resultant highs Saturday will be the main
forecast challenges in the mid range. For Friday Night: First of
all, there are some subtle differences as to where a surface frontal
boundary lies down Friday evening. The NAM solution places this
feature along the Nebr/Kansas border with the GFS solution having
this draped across central Nebraska. Thunderstorm formation will
favor where this boundary sets up Friday evening, and right now,
this is across central and southern portions of the forecast area.
With this in mind, have painted my highest pops in the south Friday
evening, transitioning this to the east overnight. As for the severe
threat, it continues to appear minimal ATTM as bulk shear is only on
the order of 10 to 20 kts. The before mentioned front will wash out
early Saturday morning. Very warm air will flow north in advance of
an approaching cold front. This front has slowed down with this
morning`s runs, so went ahead and increased temperatures east of the
panhandle and northwestern sandhills. This led to highs in the mid
to upper 90s with the exception of the far northwest where highs
will be around 90. As the front pushes east Saturday afternoon into
Saturday evening, thunderstorms are possible in advance of the
fropa. Have kept pops in place in the eastern CWA. With the strong
front plowing into abundant low level moisture, feel the models may
be under forecasting thunderstorm development Saturday afternoon and
Saturday night. Have held onto slight chance pops and this may need
to be adjusted upward as we approach Saturday.

Beyond Sunday: The front will track south into northern Kansas
Saturday night, then stall across central Kansas for Sunday. Cooler
temperatures and dry conds are forecast Sunday. By Sunday night, a
frontal boundary will lift north into the panhandle and high plains
of Colorado and Wyoming. This will lead to increased chances for
thunderstorms Sunday night. A zonal pattern aloft will commence next
week which will lead to seasonal highs in the upper 80s/lower 90s
and a threat for thunderstorms each day-particularly in the late
afternoon and evening hours.

&&

.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1139 PM CDT Thu Jul 21 2016

An upper level disturbance across Colorado this evening should
move into Wrn Neb Friday aftn and set off scattered
thunderstorms...generally from 21z onward. Storm activity will
move east northeast into and through Ncntl Neb during the evening
and overnight. Isolated thunderstorm coverage is expected until
21z Friday. Otherwise VFR is expected.

&&

.LBF Watches/Warnings/Advisories...
Heat Advisory until 7 PM CDT /6 PM MDT/ Friday for NEZ004-022-
023-035-056>058-069-070.

Excessive Heat Warning until 7 PM CDT /6 PM MDT/ Friday for
NEZ005>010-024>029-036>038-059-071-094.

&&

$$

SYNOPSIS...Buttler
SHORT TERM...Taylor
LONG TERM...Buttler
AVIATION...CDC



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