Area Forecast Discussion
Issued by NWS Hastings, NE

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FXUS63 KGID 271736

Area Forecast Discussion
National Weather Service Hastings NE
1236 PM CDT WED JUL 27 2016

Issued at 1148 AM CDT Wed Jul 27 2016

Aloft: The Westerlies were zonal over the Nrn USA with
subtropical highs over the Desert SW and over the SE. The zonal
flow was in the process of amplifying. The low-amplitude shortwave
trof that aided last night`s tstms was E of the region. Another
extended down the Ern borders of MT/WY/CO...and this trof was
responsible for tstms that are on-going at this hour. This trof
will cross the Cntrl Plains this evening...initiating the
transition to NW flow. There is one more shortwave trof currently
over WA/OR. This trof will cross the Nrn Rockies tonight and
approach the Cntrl Plains tomorrow eve. Both of these trofs will
influence tstm development this afternoon and tomorrow.

A cool front extended from low pres near MSP to near the SD/Neb
border then W into WY. Its exact location was masked by overnight
tstm activity. A meso-highs currently covered most of Neb...with
the outflow boundary now down into cntrl KS.

As always there remains a lot of uncertainty as to what will
transpire this afternoon...especially after last night`s MCS
modified the air mass. The cool front will cont to slowly slip S
into the fcst area and provide a focus for sct tstm development.

One this is certain based on satellite...a lot of solar heating
will occur resulting in destabilization. Temps 85-95F from N-S and
dwpts in the 60s should result in MLCAPE of 2000-2500 J/kg per 09Z
SREF. 0-6 km shear is fcst 27-35 kts. This combination is more
that sufficient for svr tstms.

The main question is tstm coverage. The 00Z NMM/WRF-ARW keyed on
the high-based convection currently on-going over Wrn Neb and
expanded it this afternoon. The 12Z runs have come in dry for this
afternoon/eve. The 15Z HRRR and 00Z/12Z NAM nest are dry as well
thru 00Z.

We`ll cont to monitor and provide more info as best we can.


.SHORT TERM...(Today and tonight)
Issued at 321 AM CDT Wed Jul 27 2016

Thunderstorms have been moving through much of the forecast area
early this morning. The exception has been the south and eastern
part of the area.

The upper level wave that has brought these thunderstorms is almost
through the area already this morning. Most of the short term models
have the precipitation moving out of, or dissipating, by day break.
Have kept some small POPs for early this morning, but expect that
most of the precipitation will be out of the area by morning.

Expect there to be a break this morning before the next wave moves
into the area. Models have some small timing differences, but expect
there to be some thunderstorms around mostly during the afternoon
and evening. MUCAPES during the afternoon are 2500 to 4000 J/KG.
During the evening they drop off to around 2000 J/KG fairly quickly.
The thunderstorms should continue to push to the southeast during
the overnight.

.LONG TERM...(Thursday through Tuesday)
Issued at 321 AM CDT Wed Jul 27 2016

Northwest flow across the Central Plains Thursday into the first
part of the weekend will bring intermittent chances for showers and
thunderstorms through Saturday night. There are some model
differences in timing and how far east convection will reach into
our area Thursday and have continued with scattered pops attm. The
potential exists for strong to severe storms in the sheared
environment with damaging winds and large hail the primary hazards.
Heights rise on Sunday into the first part of next week with upper
ridging bringing drier and warmer conditions to our region with
temps trending above normal into the 90s again.


.AVIATION...(For the 18Z KGRI/KEAR TAFS through 18Z Thursday)
Issued at 1236 PM CDT Wed Jul 27 2016

Significant Wx: Sct IFR tstms possible this afternoon/eve.

This Afternoon: VFR with SCT CU forming around 4K ft. Slight
chance of an IFR tstm with hail and winds gusting to at least 40
kts after 20Z. Light NE winds. Confidence: low due to uncertainty
with tstm threat.

Tonight: VFR except around SCT IFR tstms which should be departing
to the SE of the terminals. Light NE winds. Confidence: medium

Wed thru 18Z: SCT-BKN VFR clouds mainly at or above 10K ft. Light
NE winds. Confidence: medium


.GID Watches/Warnings/Advisories...


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