Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 162313

Area Forecast Discussion
National Weather Service Hastings NE
613 PM CDT Sun Jul 16 2017

.SHORT TERM...(This evening through Monday)
Issued at 346 PM CDT Sun Jul 16 2017

Aloft: 12Z RAOB data along with aircraft winds and WV imagery
revealed a ridge over the Plns with a subtropical high over WY/CO
and the Neb Panhandle. Trofs were over the Ern USA and Pac NW.
There was a small low over Ern CO meandering within the broad
anticyclonic circulation from the Desert SW into the Plns. This
low will be the primary influence on the wx here thru tomorrow.
Spaghetti plot shows the deterministic mdls are tightly clustered
on this low lifting NNE into Wrn Neb tonight then turning more E
across the Sandhills tomorrow. Meanwhile...falling heights across
Canada will force the ridge to the GtLakes resulting in broad WSW
flow for the W 2/3 of the CONUS.

Surface: A cool front had sagged into Nrn/Ern Neb but was lifting
back to the NE as a warm front due to low pres advancing across
cntrl Canada. A cool front trailed from this low into the Pac NW.
Weak high pres extended from the Srn Plns into the SE USA. The
pres grad will gradually increase thru tomorrow with modestly
strengthening S-SE flow as the Pac NW cool front progresses into
the Nrn Plns...and pres falls in the lee trof over WY/CO.

Tonight: M/clear to start...but a cluster of tstms should develop
over Ern CO and gradually migrate E/NE into the Wrn CWA after
midnight. With a weak low-lvl jet (20-25 kts) and increasing
clouds...went a little warmer with low temps (68-72F).

Tomorrow: There is considerable uncertainty with how much rain
falls. If it is similar to what happened today...there should be a
diminishing area of rain W of Hwy 281 or even 183 during the
morning...along with substantial cloud cover. That cloud cover
should thin with redevelopment of sct tstms in the afternoon-eve.

0-6 km shear will slowly increase from 15 to 20 kts. Even still
updrafts will still be pulse-type. MLCAPE will be as high as 1500
J/kg which should support a couple marginally svr tstms.

High temps are below average confidence. We may be too warm W of
Hwy 281 if cloud cover remains thick into the afternoon.

.LONG TERM...(Monday night through Sunday)
Issued at 346 PM CDT Sun Jul 16 2017

Aloft: Little has changed from prvs reasoning the last couple
days. Hot subtropical high pres (597-598 dm) will be parked over
the cntrl USA Tue-Fri. It will probably be suppressed next wknd as
a decent shortwave trof or two is fcst to move in from the Pac
and head E along the US-Can border Fri-Sun. There remains
considerable uncertainty within the Westerlies with the position
of a low fcst to be over the Gulf of AK and the downstream trofs
along the US-Can border. In fact...the 12Z/15 and 00Z EC are 180
deg out of phase over the Pac NW at 00Z/23. The 12Z run is in
phase. The mdls are in best agreement on the lead trof fcst to
move into SW Canada Thu-Fri. Pattern recognition suggests this
trof will cont E and then amplify a bit next wknd as it heads into
the persistent trof over the NE USA. This would support
development of a ridge over the Nrn Rockies and WNW flow here.
That is what the 00Z EC ensemble mean and GEFS reforecast are
indeed indicating.

Please see the 1528Z WPC Extd Fcst Dscn for additional commentary
on the difficulty of this pattern.

Surface: The Nrn Plns cool front will sag into Neb Tue and it
will modestly oscillate N and S thru the rest of the week...though
it will hardly be noticeable based on temps.

Heat: It will be hot with the upr-lvl high overhead. Daily highs
in the 90s with Furnas/Gosper/Harlan counties down into N-cntrl KS
reaching 100+. Wed is looking like the hottest day with 100+
possible over S-cntrl Neb as well.

The 00Z EC ensemble probabilities for high temps 100+ are very
high for N-cntrl KS Wed-Fri (80% Wed-Thu and 90% Fri).

Heat Advisories will probably be issued for at least a few
counties Tue-Fri.

Rain: The 850 mb front will remain N of the CWA which means the
highest probability for MCS activity will probably remain to the
N. Chances for rain are poor with the high aloft.


.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 607 PM CDT Sun Jul 16 2017

The main concern for the TAF period is the timing of showers and
thunderstorms on Monday as upper level wave slowly migrates across
the central plains. The majority of the TAF period is expected to
remain dry with the better chances for precipitation arriving
after 00Z Monday, but have carried a VCTS for KEAR in the late
afternoon. South winds will increase by late afternoon averaging
near 15kts.





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