Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 211750

Area Forecast Discussion
National Weather Service Hastings NE
1250 PM CDT Wed Mar 21 2018

Issued at 1203 PM CDT Wed Mar 21 2018

Regarding the "final word" on the Dense Fog Advisory:
As it turned out, the original Advisory-extension through 1 PM was
in fact overly-generous, as satellite trends clearly show that the
last of the fog within northern Howard/southern Greeley counties
has rapidly dissipated within the past hour. As a result, these
last few counties have been cleared, and the entire dense fog
situation from this morning is finally/officially history.

Otherwise, the forecast for the remainder of the afternoon should
stay pretty straightforward. Although a band of increasing mid-
level clouds will drift into especially southwestern counties, am
not currently expecting any sprinkle activity from them.
Meanwhile, most of the CWA should still see plenty of sunshine
this afternoon. Have made very little change to inherited high
temps, still aimed from mid-50s northeast to mid-60s far

UPDATE Issued at 1017 AM CDT Wed Mar 21 2018

Regarding the Dense Fog Advisory:

Although dense fog has dissipated across the vast majority of the
original early-morning Advisory area, satellite imagery, short
term model-visibility progs (such as HRRR), and most importantly
ground-truth from law enforcement, indicates that a fairly narrow,
stubborn area of dense fog remains in a small portion of our north
central CWA. This is mainly centered over Howard County, but
likely extends into at least southern Greeley and a small portion
of mainly northwest Hall as well. As a result, have extended the
Dense Fog Advisory through 1PM for these 3 counties. Model data
suggests this should be plenty generous time-wise, and may very
well cancel Hall early based on latest trends.


.SHORT TERM...(Today and tonight)
Issued at 456 AM CDT Wed Mar 21 2018

Fog channels on satellite reveal an expanding area of dense fog
this morning near I-80 and expanding to much of the area to the
north. The area of dense fog is quite irregularly shaped and
morphing rather unpredictably, so be ready for quickly changing
visibility this morning and icy spots forming from freezing fog
freezing onto contact of surfaces.

Fog should burn of by mid to late morning, but I did lower the
highs today by a couple degrees as we will get off to a bit of a
slower start at warming because of the fog and subsequent stratus
that was produced from it. Also, a strip of larger scale stratus
still hanging on in the far eastern CWA that should finally give
way this morning. Still should be a rather mild day with plenty
of sun and highs in the upper 50s to lower 60s thanks to upper
level ridging building in and a surface warm front tries its best
to move north.

The warm front should make it just north of the CWA tonight, and
will give us quite mild lows in the 30s to around 40.

.LONG TERM...(Thursday through Tuesday)
Issued at 456 AM CDT Wed Mar 21 2018

Upper level ridging will continue and will make Thursday even
milder with highs in the mid 60s to lower 70s, and with rather
relatively light wind, should feel like the warmest day of the
week for much of the CWA.

The surface front sags south a bit for Friday, which will give us
quite a temperature spread from upper 50s/near 60 north to near 80
far south in north central Kansas. Still enough instability to
keep thunder in the forecast for Friday afternoon into the evening
for much of the CWA.

Highs over the weekend will be back into the 50s for most behind
the upper ridge trough axis, but still seasonably mild, behind the
mean upper trough axis and within southwest flow aloft. Seasonable
temps in the 50s thereafter are forecast into next week.


.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Thursday)
Issued at 1250 PM CDT Wed Mar 21 2018

Confidence is fairly high in VFR ceiling/visibility, although much
of the period will likely feature considerable mid-level cloud
cover, and there may be an outside chance of some light haze/fog
late tonight/early Thursday morning. However, confidence in sub-
VFR visibility is deemed too low to formally advertise this small
possibility at this time. Wind-wise, most of the period will
feature southerly or southeasterly speeds near-or-under 10kt,
although especially KEAR could sustained speeds closer to 12kt
this afternoon. As introduced by the previous forecaster, there is
still some concern for some marginal low level wind shear (LLWS)
mainly between 06-12Z, as winds within roughly the lowest 1500 ft
increase to around 35kt from the south-southwest, creating around
30kt of shear magnitude between the surface and this level. Again,
this appears to be a fairly marginal LLWS situation, but given it
was already in the previous TAF issuance, see no compelling reason
to remove it at this time.




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