Area Forecast Discussion
Issued by NWS Omaha/Valley, NE

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FXUS63 KOAX 250815
AFDOAX

Area Forecast Discussion
National Weather Service Omaha/Valley NE
315 AM CDT Mon May 25 2020

.DISCUSSION...
Issued at 315 AM CDT Mon May 25 2020

Timing of highest precipitation chances and precipitation amounts
will provide the main forecast challenges.

Pattern at 500 mb features a trough axis extending from eastern MT
down into NM. There was a weak closed low just west of the MT/ND
border and possibly two others - one in CO and another in TX. Dirty
southerly mid level flow has been and will continue to be rather
problematic. Regional radar loop as of 3 am showed that showers and
embedded thunderstorms had spread north across much of central and
southeast NE but also into northeast NE. There appeared to be one or
possibly two MCVs across KS. These should lift north with periods of
moderate and occasionally heavy rain. Will leave the Flash Flood
Watch in effect and extend until 7 pm. Soils in parts of southeast
NE are quite wet and streams should still see rises today.

Vort maxes lifting northward ahead of the main trough to our west
have been one of the forcing mechanisms over the past 24 hours or
so. It is not clear if there will be a break in the precipitation,
later this morning but intensity should be less. Another area of
stronger lift could push into southeast NE by late this afternoon.
The overall severe threat seems fairly low, with limited
instability, but a few strong storms are possible. PW values
remain mostly in the 1.2 to 1.6 inch range today. Afternoon highs
should reach the mid to upper 60s in the northwest half of the
forecast area, and around 70 to the mid 70s in the southeast half
of the forecast area.

Models suggest that the closed low to the north will track into
southern Manitoba by 12Z Tuesday, with the main trough axis
extending down into TX. The more pronounced south to north mid
level flow decreases on Tuesday, as the low over TX closes off
and starts to become detached. while the 500 mb flow from the
Pacific NW to the Northern Plains strengthens. Drier air starts
to work in from the west on Tuesday, with highest PW values of
over 1.5 inches shifting eastward out of our area. Temperatures
are expected to top out in the lower or mid 70s on Tuesday.

As the mid level flow changes, this should trend toward a drier
pattern for our area for the mid and later parts of the week. By
Thursday, a ridge should be located from AZ up into western Canada
putting the Central Plains in weak northwest flow. That ridge is
forecast to strengthen and move/build eastward through Sunday.
Highs most of the period should range from the mid 70s to lower
80s, warming to the 80s by Monday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1138 PM CDT Sun May 24 2020

Showers and thunderstorms ongoing over south-central NE and
north-central KS are expected to overspread the area overnight
into Monday morning with periodic showers continuing through the
day on Monday. Prior to the onset of showers, some patchy fog
could develop at KOMA and KLNK where winds will remain lighter.
Otherwise, expect ceilings to lower overnight with prevailing MVFR
conditions by Monday morning. The MVFR conditions will persist on
Monday with the potential for some IFR ceilings developing by
Monday evening.


&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Flash Flood Watch through this evening for NEZ030-042-050-
     065>068-078-088>093.

IA...Flash Flood Watch through this evening for IAZ079-080-090-091.

&&

$$

DISCUSSION...Miller
AVIATION...Mead



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