Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Omaha/valley NE
305 PM CDT Friday Oct 31 2014

Short term...(tonight through monday)
issued at 305 PM CDT Friday Oct 31 2014

Temperatures will provide the primary forecast challenges through
Sunday...then our attention turns to precipitation event that is likely
for at least parts of the area Sunday night into Monday.

The large scale pattern at 500 mb features a meridional progressive
flow at 500 mb. Troughs are currently over the eastern United States
and just off the West Coast...while a ridge stretches from Mexico
up through Saskatchewan. The middle/upper level trough to the west
will move into The Rockies Sunday. Flow becomes more split by this
time with one branch of the jetstream diving south toward Baja California
California...then that turns northeast into our area. This will
bring moisture and some elevated instability northward with a warm
conveyor belt flow. It appears that the northern stream energy
should not have much of an impact on our area.

Very cool low level air had settled down over the upper Midwest and
northern plains. At 20z high pressure at the surface stretched
from southwest Ontario southwest into eastern Nebraska with a maximum
of 1036 mb in central Minnesota. This high will build eastward
tonight with southerly flow increasing. Winds will increase even
more for Saturday. This is expected to help push highs into the
upper 40s and lower 50s. Warm advection continues into Sunday...
with highs reaching around 60 to the middle 60s. The combination of
clouds...precipitation and a cold front pushing into the area from the
northwest should keep highs down a bit Monday...especially across
northeast Nebraska where cold advection moves in during the
morning.

Long term...(monday night through friday)
issued at 305 PM CDT Friday Oct 31 2014

Precipitation will linger Monday night...but the main middle level trough axis
and upward vertical motion move out of the area by 12z Tuesday.
Very dry air moves in behind this system.

The GFS/ECMWF/Canadian models are in good agreement at the start of
this period. Large scale features start to have less agreement to
our south and southwest by middle week...but there is better confidence
locally until about Thursday. Look for generally northwest flow
behind that departing shortwave through Wednesday. The 00z European model (ecmwf)
tried to bring a weak closed low northeast out of New Mexico and
into southwest Nebraska by late Friday with some precipitation. However
that precipitation event does not seem likely...and was discounted for now
since the 12z European model (ecmwf) and 12z GFS were much drier for our area on
Friday.

So...for now will keep the forecast dry from Tuesday into Friday.
Highs should be mainly 50s to lower 60s with lows mostly in the
30s to lower 40s. &&

Aviation...(18z tafs for kofk...klnk and koma.)
Issued at 1234 PM CDT Friday Oct 31 2014

VFR conditions are forecast through the taf period. Look for a
patch of cirrus to move into the area with some broken high
clouds...moving out later tonight and Saturday. Light and variable
winds under 10kts...switching to the southeast through this
evening. Southeast winds increase at kofk after 06z at kofk and
after 12z at koma and klnk with with 15-18kt south winds gusts
20-30kt after 15z.

&&

Oax watches/warnings/advisories...
NE...none.
Iowa...none.
&&

$$

Short term...Miller
long term...Miller
aviation...zapotocny

National Weather Service Glossary of Abbreviations