Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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000
FXUS63 KOAX 070915
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
315 AM CST Thu Dec 7 2017

.SHORT TERM...(Today through Saturday)
Issued at 313 AM CST Thu Dec 7 2017

Trough east/ridge west pattern continues (and will for a long time).
Subjective 00Z upper-air analysis indicates broad upper-level trough
centered on the Great Lakes but spanning the Great Basin to New
England. Embedded shortwaves were noted near the MN-IA border and
near the AZ-NM border. Upper-level ridge was centered along the
Pacific coast, and upper-level jet was strongest in advance of the
trough, from the mid-Atlantic toward New England. 850mb temperatures
of -10C or colder were in place from eastern MT through southern
NE/IA and toward southern MI. Surface high at 08Z was centered in
CO, with weakening surface pressure gradient across the High Plains,
while tigher pressure gradient lingered east of the MO River toward
the Great Lakes.

You know it`s a slow weather day/week when the biggest issue of the
entire forecast is whether or not to include flurry mention
today/tonight. Coolest airmass of the week is moving across the area
early today, and the airmass also is fairly dry. Rising 500mb
heights are expected today and tonight, and lower levels just don`t
seem to have enough moisture as lapse rates steepen this afternoon
to squeeze out flurries. Surface to mid-level moisture does increase
tonight, but whether it is enough to allow even flurries to develop
is unclear, especially given that any potential shortwave trough
moving through the area (weakly evident as a bit of Q-vector
convergence) would be quite weak and transient. Tossed in a chance
flurries mention for late tonight, but am not feeling too strongly
about the chances, and the impacts would be negligible anyway.

Temperatures will moderate on Friday and Saturday as 850mb
temperatures rise to and then fluctuate around the single digits
below zero to near 0C. Have bumped up winds on Friday before ridging
on Saturday brings a respite from the northwesterly winds of the
last several days.

.LONG TERM...(Saturday night through Wednesday)
Issued at 313 AM CST Thu Dec 7 2017

Temperature fluctuations will be the main forecast concern through
Wednesday. With 850mb temperatures rising into the single digits
above 0C to near 10C, highs on Sunday should be the warmest of the
week, despite west to northwest winds. Temperatures drop again on
Sunday night/Monday as a shortwave in the northwesterly flow brings
a shot of colder air, with 850mb temperatures back to the single
digits below 0C. Also have bumped up winds on Sunday night/Monday
with the cold air advection regime. Similar temperature fluctuations
will continue through Wednesday, with brief rises and falls that
keep temperatures near to slightly above normal. The pattern remains
dry, and any potential periods of flurries/sprinkles are too
transient to discern this far in advance, and again, would have
negligible impact anyway.

&&

.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1135 PM CST Wed Dec 6 2017

VFR conditions are expected through the period with diminishing
northwest winds as high pressure builds southeast across the
region from the western high plains.


&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Mayes
LONG TERM...Mayes
AVIATION...Fobert



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