Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 192037
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
337 PM CDT Sun Mar 19 2017

.SHORT TERM...(tonight through Wednesday)
Issued at 335 PM CDT Sun Mar 19 2017

Surface low located over north central Nebraska late this
afternoon, with attendant cold front moving across South Dakota
and dryline bisecting the state. Modest boundary layer moisture
available, but with only weak convergence along dryline, so little
if any diurnal development. Better dynamic forcing will be
delayed until this evening, along with enhanced isentropic ascent,
thus cannot discount isolated-widely scattered tsra development
along warm front, that will be located across extreme eastern part
of the CWA. Continued slight chance PoPs for extreme southeast
Nebraska and southwest Iowa. The rest of the forecast area will
remain dry at least through Monday evening.

Low level cold advection will keep temperatures 15 to 20 degrees
cooler than those seen today, especially if narrow band of stratus
develops along H8 front as depicted by short term models. Next
chance for precipitation arrives overnight Monday. Weak shortwave
moving around base of eastern Canada vortex drops southward from
northern Rockies. Vorticity somewhat channeled initially, which
may limit precipitation development until pre-dawn hours. Short
range models have a slightly warmer temperature profile, and most
locations should experience mainly liquid precipitation. Due to
warmer temperature profiles, lowered snow ratios slightly and thus
accumulating snow totals. Temperatures may need to be lowered
in suceeding forecasts, but Tuesday looks to be a rather cool and
raw day. Precipitation exits the area by Tuesday evening

Upper H5 ridge builds into central Plains Tuesday evening, but
another weak short wave will overtop the ridge, giving the area
yet another chance for precipitation on Wednesday. Low level
cold advection will keep temperatures at or below for the onset
of precipitation, thus another chance of wintry mix.  For now
kept precipitation type rain and snow.



.LONG TERM...(Wednesday night through Sunday)
Issued at 335 PM CDT Sun Mar 19 2017

Medium range models consistent in placing upper ridge ver the
area at the start of the extended period, then solutions depart
with spread among the operational and ensembles. At time,
operational GFS the fastest in moving H5 low out into southern
plains Thurs/Fri, while EC/Can and GEFS members all a little
slower and drop center of low a little further south. At least
temperatures a little more clear cut, and precipitation type
appears to be liquid.

&&

.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 132 PM CDT Sun Mar 19 2017

VFR conditions are expected through the TAF period. South to
southeast winds 10 to 20 kts to become variable then northeast at
KOFK this evening around 02Z...and after 06Z aft KOMA and KLNK.
Some of the models are hinting at some stratus Monday morning
after 12Z and will assess in future forecasts.


&&

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

$$

SHORT TERM...Fortin
LONG TERM...Fortin
AVIATION...Zapotocny



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