Area Forecast Discussion
Issued by NWS North Platte, NE

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43
FXUS63 KLBF 120939

Area Forecast Discussion
National Weather Service North Platte NE
339 AM CST Tue Dec 12 2017

Issued at 339 AM CST Tue Dec 12 2017

H5 Analysis from earlier this evening had high pressure located
over northern Nevada with a ridge extending north into the
Northwest Territories of Canada. East of this feature, a broad
area of low pressure was located over eastern Canada with a trough
of low pressure extending south to Florida. Within this trough of
low pressure, shortwaves were noted over Ontario and the northern
Great Lakes, as well as the lower Missouri valley. West of the
western CONUS high, a strong shortwave was analyzed off the coast
of British Columbia. At the surface: High pressure was dominant
across the intermountain west tonight and a piece of this high
extended east into Nebraska. A warm front extended from North
Dakota into central Nebraska. Along and west of the warm front, an
area of cloudiness was present North Dakota south into central
Nebraska. Temperatures underneath the cloud deck were in the 30s
across eastern portions of the forecast area, while in the west,
under clear skies and light winds, temperatures had fallen off to
the teens.


.SHORT TERM...(Today and tonight)
Issued at 339 AM CST Tue Dec 12 2017

High pressure will track south into the southern plains this
morning with a surface trough of low pressure developing from
North Dakota south to Colorado this afternoon. Thanks to westerly
winds along the trough, much warmer air will push into the
forecast area today. H85 temps will reach 6 to 10C this afternoon
from east to west this afternoon. Winds will be fairly light so
mixing will be limited. However, with full sun expected, highs
will reach the 50s with readings around 60 in the far southwest.
Fire weather concerns will be limited this afternoon, even with
min RH around 20 percent, as winds will only top out around 10
MPH. A clipper system will dive south from southern Canada into
Minnesota overnight tonight. a cold front will approach northern
Nebraska toward 12z Wednesday. South of the front, northwesterly
winds will increase, leading to mild temperatures overnight. Lows
will be in the 30s with mid 20s in the Platte River Valley.

.LONG TERM...(Wednesday through Monday)
Issued at 339 AM CST Tue Dec 12 2017

Amplified upper level ridging will continue across the western Conus
through the remainder of the work week but then show signs of
breaking down with a series of strong Pacific shortwaves.  The
amplified ridge will provide for north northwesterly flow across the
plains, which will force a series of low amplitude waves and fronts
across the region.  Wednesday a clipper type wave will dive south
with a strong front.  The models continue to show a dry passage for
the Sandhills, but another period of gusty winds.  The latest
guidance indicates gust potential of 35-40 mph.  Given the recent
dry spell, large range fire spread will be possible with these
projected wind speeds, but critical spread rates are not anticipated
as CAA will cool highs into the 40s and lower 50s, keeping the RH in
the 20 to 30% range or higher and the sun angle for this time of
year is quite low.  The next front arrives early Thursday with some
upper level support in the form of a 120kt mid level jet.  North
Central Nebraska is shown to be in the left front quadrant of this
jet with the models suggesting light precipitation potential for our
northern zones as some Pac moisture is shown to top the ridge.  IF
precipitation is realized, initially temperatures would be
supportive of snow, but that would transition to a mix or all rain
by midday.  Regardless, QPF amounts are indicated to be light with
at most a few hundreths anticipated. Wind speeds on Thursday will be
elevated once again due to solid mixing with the front and a good
pressure gradient, but CAA will cool temperatures further with non-
critical RH expected.

For the weekend and early next week, the ridge is shown to break
down with a strong Pacific trough.  The long range models are at
odds where the best forcing is expected.  The GFS is further west,
the EC targets the plains.  Confidence in any particular solution is
low, but given the dry pattern as of late, we are hedging toward the
drier GFS.  Temperatures through the extended look to be largely
above average, but out 9-10 days there are indications of an Arctic
intrusion with a big trough to our west.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1151 PM CST Mon Dec 11 2017

The area of MVFR cigs across portions of ncntl into cntrl Nebraska
should dissipate by 12z Tuesday. High pressure across the cntl
high plains will drift southward overnight with sfc low pressure
quickly moving southeast into Saskatchewan and southern Manitoba
on Tuesday. The result should be generally clear skies developing
overnight lasting through Tuesday evening.




SHORT TERM...Buttler
LONG TERM...Jacobs
AVIATION...Roberg is the U.S. government's official web portal to all federal, state and local government web resources and services.