Area Forecast Discussion
Issued by NWS Hastings, NE
FXUS63 KGID 191946
Area Forecast Discussion
National Weather Service Hastings NE
246 PM CDT THU MAY 19 2016
Issued at 246 PM CDT Thu May 19 2016
More active weather pattern set to move into the forecast area by
the end of the weekend and throughout next week is the main focus
for the forecast. In the mean time...look for increasing low level
moisture the next few days with climbing dewpoints...forecast to
reach 60 degrees by Saturday. That will bring a humid feel to the
area. Along with incoming moisture...will be the risk for
overnight fog tonight and and again Friday night. Mid level warm
advection...steepening lapse rates and a briefly favorable jet
position should be enough focus for isolated thunderstorms late
Friday night...which will linger through Saturday. While the jet
slides east of the area...the warm/moist advection continues into
Sunday so there is a steady diet of low precipitation chances.
Much better shower/thunderstorm chance sets up Sunday night as a
front tries to move through with a an upper trough moving
northwest of the area...embedded in a developing southwest upper
flow. Actually decent continuity in time and space from run-to-run
of models gives good confidence in timing of later Sunday night
and very early Monday morning. Coverage looks widespread with
good instability and strong low level jet feeding into the system.
Potential for a decent rain making MCS...possibly with some strong
to isolated severe storms. The timing is a bit of drawback though
for a lot of severe weather.
Another period of concern is Tuesday afternoon/evening...with lee
cyclogenisis developing and forming a warm front near I-70. This
is worth watching as the time nears for its thunderstorm potential
and even severe storm potential.
In general...temperatures should be on a slow incline given the
moisture increase and warm advection...but there will still
periods clouds holding temperatures back at times. However...we
still should be in the normal range at least for high temperatures
if not above.
.SHORT TERM...(Today and tonight)
Issued at 348 AM CDT Thu May 19 2016
Aloft: The flow remains convoluted and split with NW flow over
the Cntrl Plains and a ridge over the Rockies. A trof extended
from Wrn KS SW into NM/AZ. These two streams then merged over the
Ern USA. The trof will slowly advance E across the Srn Plains thru
tonight with NW continuing over the Cntrl Plains as the ridge
inches closer. Meanwhile...the low moving into the Pac NW will
cont dropping S along the W coast. What`s left of this low will be
a player in our wx here early next week.
Surface: The primary polar front will remain over the Srn USA.
High pres was over the Great Lakes and encompassed much of the
Cntrl/Ern USA. This high will creep a little E of its present
location by daybreak Fri. Meanwhile...the Pac cool front entering
the Pac NW will cont pressing further inland. A leeside trof will
develop today...strengthening the pres grad over the Plains.
Today: Very similar to yesterday but with a bit more wind. SSE
winds will gust 20-25 kts...primarily N and W of the Tri-Cities.
High temps about 5F below normal.
Tonight: Diurnal Cu dissipate early. Strengthening S winds now
thru tonight will be advecting moisture/low clouds N underneath
the cap. It`s Nrn fringe will be eroded by diurnal heating
today...but it will resume its northward surge tonight. So low
stratus and light fog should invade from S-N tonight. So expect
skies to become cloudy after midnight.
.LONG TERM...(Friday through Wednesday)
Issued at 348 AM CDT Thu May 19 2016
For Friday, an upper level longwave trough with a closed low will
continue amplifying as it moves onshore of the West Coast.
Meanwhile, we will experience ridging over the Plains for Friday
and Saturday, helping to warm things up, along with increasing
wind from the south, and increasing moisture as well, although
models seem to be a bit liberal with the moisture flux. Drizzle
looks unlikely for Friday morning as sounding indicate very
shallow moisture in low- levels. We could have so me potential for
fog along with stratus, however. This could all happen again
Friday night/Saturday morning with a similar scenario, only I
bumped up temperatures Saturday morning with good warm air
advection and plenty of sky cover. I don`t imagine any site
getting below 60, unless there is a rogue shower that will bring
temperatures temporarily down somewhere, but chances of this are
The western mean trough will begin to broaden by Saturday night
and begin ejecting pieces of energy out into the Plains toward the
latter half of the weekend and into the next work week. A surface
trough in the lee of the Rocky Mountains may spark some
thunderstorms on Saturday in the western High Plains as moisture
modestly increases, but this will most likely stay west of our
CWA. More High Plains convection could get going on Sunday and
move in Sunday night. We will stand a better chance at convection
Sunday night with increased low-level moisture and theta-e axis
moving farther east as most models are converging on the Sunday
night shortwave really helping to spark some thunderstorms. We
could even get a strong storm if things hold together.
Timing of these relatively small upper level features will be
difficult, so confidence is not high for pinning down the best
periods for rain chances next week. With a surface boundary
lurking nearby, we will have a shot of precipitation for every
period next week.
Leaned closer to ensemble solutions rather than any particular
operational run, especially the further out in time we go.
.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Friday afternoon)
Issued at 1226 PM CDT Thu May 19 2016
VFR conditions are expected this afternoon for both KGRI and KEAR
with increasing south winds and scattered mid clouds. Low Level
moisture increases tonight...expected some low clouds and patchy
fog development. Not 100% sure on the fogs expanse...but certainly
enough hints to warrant its inclusion down to MVRF visibilities
and IFR ceilings. It may take a bit of time to lift the fog Friday