Area Forecast Discussion
Issued by NWS North Platte, NE

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FXUS63 KLBF 241148

Area Forecast Discussion
National Weather Service North Platte NE
648 AM CDT Sat Jun 24 2017

.SHORT TERM...(Today and tonight)
Issued at 336 AM CDT Sat Jun 24 2017

Quiet sensible weather conditions will largely prevail over the next
24 hours. NtMicro RGB satellite imagery shows mainly thick mid
clouds (ceilings generally 6-9 kft) over western NEB that are
expanding in coverage towards south central NEB. Latest water vapor
imagery shows an upper level ridge extending from southwest US to
offshore the Pacific Northwest and a broad upper level trough across
the central and northeast US. Cyclonic flow prevails across the
Central Plains with a mid-level closed low apparent over ND moving
southeastward. Latest temperatures at the top of the hour span near
40 degrees to the mid 50s across western NEB, coolest in far
northern NEB and north central NEB.

Over the next 24 hours the upper level ridge will move onshore and
extend from the southwest US into the Pacific Northwest to western
Alberta by late tonight. Meanwhile, the mid-level closed low will
continue to track southeastward into the Upper Great Lakes tonight
and will weaken into an open wave. Northwest flow will prevail
overhead through the period. Surface high pressure currently extends
into the Central High Plains from the Northern High Plains and will
continue to persist across the region. Clouds will affect much of
western NEB through the morning with improvement/decreasing sky
cover expected late morning into the afternoon. Otherwise, north
central NEB is expected to stay mostly sunny and will also feature
more modest breezes (gusts up to 25 MPH). Highs today will be
similar to slightly warmer than yesterday though about 5 to 10
degrees below seasonal normal values. Increasing sky cover late this
evening and overnight across western NEB. Lows are anticipated to
read slightly warmer than this morning, albeit still in the 40s to
around 50, warmest in extreme southwest NEB.

.LONG TERM...(Sunday through Friday)
Issued at 336 AM CDT Sat Jun 24 2017

The GFS has been fairly consistent in a fairly strong area of FGEN
centered around H7 targeting far sw Nebraska Sunday.  The ECMWF
remains southwest and weaker with the FGEN.  The discrepancy between
the two camps yields low confidence in the light precipitation
potential. Thus will keep pop chances at 30% or less across far sw
Nebraska through the day and if precipitation is realized, amounts
would be light. The GFS allows for the inclusion of thunder as the
model thinks the atmosphere will be weakly unstable.  So since we
plan to retain pops, will include the mention of ISO T. Temperatures
on Sunday will once again be moderated by northwest flow and cool
sfc high pressure to the east.  Highs will remain in the 70s for
most locations.

Widespread appreciable moisture has been tough to come by over the
past month, so when the models indicate a fairly strong signal, our
attention and certainly the ag/ranching community takes note.  There
remains good continuity in a closed low advancing from the Gulf of
Alaska southeast in British Columbia late this weekend.  Then the
low is suggested to cross the Canadian Rockies and settle over
Saskatchewan mid next week.  A southwestern extension of a trough
from the low will follow a similar path, but across the northern
American Rockies and break down a ridge over the central/northern
Plains.  As it does so, moisture return from the Gulf of Mexico will
begin it/s surge northward.  The degree of moisture return is what
muddles the forecast as there is some disagreement in the main
modeling camps. A general consensus would suggest TD/s in the mid to
upper 50s to lower 60s along and east of Highway 83 by mid-afternoon
Tuesday. If the dry push from the west/southwest associated with a
trailing front and/or dryline arrives early, then, much needed rain
will develop east.  As most of the models sit now, it is suggested
that a sfc trough extending south from a developing Black Hills low
will serve as a focus for storm development over the central
Sandhills, which then would grow upscale into a convective complex
late Tuesday night and into Wednesday bringing widespread moisture
to the region. Ample shear and moderate instability would suggest a
severe wind/hail threat. With a possible drier solution, gusty west
wind, hot temperatures, low RH and the beginning sales of
recreational pyrotechnics, range fire starts would begin to become
challenging to control, especially out across our western zones.  A
recent call to a fire partner revealed that the 1 hour grasses are
stressed in exposed areas and enough dead and down material remains
from previous growing seasons for range fire to spread.  But RFW
criteria fire spread is not yet expected.  A fire related
climatological side note, RFW criteria fires for our western zones
typically begin to increase late June/first week of July when those
grasslands are showing stress from the initial stages of drought.
Wetting rains are needed. The prospects of wetting rains will once
again hinge on the quality of moisture return, which luckily we
still have several days to hammer that out.

The expected convection should draw the front to the south and east
on Wednesday, but a broad trough will remain over much of the west
central and central US.  Several impulses will pass through the near
zonal flow, which would spark off additional precipitation chances
mid and late week.  Best chances come Thursday into Friday.
Temperatures will be seasonal or below average through the end of
the work week.


.AVIATION...(For the 12Z TAFS through 12Z Sunday morning)
Issued at 640 AM CDT Sat Jun 24 2017

Latest satellite imagery and surface plot shows mid-level clouds
across western NEB into south central NEB with ceilings between
9-12 kft. Elsewhere, skies are mostly clear. VFR conditions
currently prevail and are expected to continue through the TAF
period. Sky cover is expected to improve late morning into the
afternoon across western NEB. Winds will increase today from the
northwest, strongest over north central NEB with gusts up to 25
MPH are possible. Winds will lessen during the evening and become
light. Increasing clouds then late evening and overnight,
however, clouds should remain high-end VFR (greater than 7 kft).




LONG TERM...Jacobs
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