Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/19/18

Area Forecast Discussion

National Weather Service Hastings NE

 627 PM CDT Wed Jul 18 2018

.UPDATE...
Issued at 626 PM CDT Wed Jul 18 2018

Just issued svr tstm watch 281 until 06Z. We cont to monitor tstms
upstream and it currently appears the best chance of tstms tonight
will be N of a line from ODX-GRI-JYR. We were generous with the
counties in the watch to the S and W of that area because some
CAMs suggest additional tstm development W of the on-going
activity.

We will cont to monitor the situation thru the evng...but for now
the highest risk for svr tstms in the next 2 hrs is over Valley
and Greeley counties.

&&

.SHORT TERM...(This evening through Thursday)
Issued at 248 PM CDT Wed Jul 18 2018

Focus of attention is on the wave moving through the
northern/central Plains tonight. As of now, subsidence behind
morning convection should keep us largely dry this afternoon and
early evening, but convection has already developed along an area
of low-level convergence in South Dakota and several models send
this convection to the south tonight. Not a lot of agreement among
short term models. For example, the NAMnest and NSSL WRF takes
convection as far west and south as our western CWA and north
central Kansas, whereas the HRRR barely clips us in our northeast.
There is enough uncertainty to include nearly our entire CWA with
at least a slight chance of thunderstorms, with higher chances in
our northeast.

Since we`ve seen a lot of sky cover, this may hinder any
development here, but with strong bulk shear for July and MLCAPE
of over 1000 J/kg, there is enough support for thunderstorms to
propagate into our area. A tornado is not completely out of the
question in our north, considering our 0-1 km helicity above 50,
especially if the mode of convection will be discreet cells rather
than linear, which is still a bit of a question, even in the short
term. Confidence in this forecast is not all that high, as
numerical models in the short term have regularly failed over the
past couple of days, and there is still a shortage of agreement
and consistency among them.


.LONG TERM...(Thursday night through Wednesday)
Issued at 248 PM CDT Wed Jul 18 2018

Warm advection type showers are still on the table for late
Thursday night, and elevated instability and favorable mid-level
lapse rates could aid in giving us some marginally large hail and
severe wind gusts.

Although the subtropical ridge builds west into the Great Basin
stretching into the southern Plains, we will largely remain on
the northeastern and eastern periphery which will make us
vulnerable to a series of shortwave troughs, especially from the
latter half of the weekend into next week.

Temperatures should be rather typical for summer, with highs in
the 80s and lower 90s and lows in the 60s for the most part.

&&

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday)
Issued at 620 PM CDT Wed Jul 18 2018

Significant Wx: A brief IFR +TSRA possible tonight.

Tonight: VFR...but svr tstm watch #281 is in effect until 06Z.
Can`t rule out a +TSRA with G50 kt. Outside of any tstms...SE
winds 10 kt or less will become VRB after 07Z. Confidence: Medium

Thu: VFR with a few CU forming around midday with bases lifting to
6-7K ft. NW winds 5-10 increasing to 10-20 kt. Confidence: High

&&

.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&

$$

UPDATE...Kelley
SHORT TERM...Heinlein
LONG TERM...Heinlein
AVIATION...Kelley



Area Forecast Discussion

National Weather Service Wilmington NC

 953 PM EDT Wed Jul 18 2018

.SYNOPSIS...
A weak cold front will continue to move southward along the
South Carolina coastline, and will stall south of Charleston on
Thursday. The front should return northward on Friday. Unsettled
weather is possible Saturday through Tuesday with a chance of
showers and thunderstorms each day.

&&

.NEAR TERM /THROUGH THURSDAY/...
As of 1000 PM Wednesday...With the exception of a shower near
Surf City, rainfall has ended across our forecast area. I`ve
adjusted PoPs downward or removed them entirely for the
overnight period in agreement with the latest HRRR and RAP
models, although I did hang on to isolated showers a bit longer
across Darlington and Florence counties where recent convective
development across the Camden and Columbia area could
conceivably drift eastward. Elevated instability will persist
overnight, particularly across South Carolina and offshore
closer in proximity to the surface front which continues to sink
southward. Discussion from 645 PM follows...

A cluster of storms near Southport and another near Georgetown
and the Santee River are all that`s left of today`s convection.
The front appears to have been bumped southward by the
convection, with either northeast or northwest winds now
observed in Georgetown and Kingstree, SC. Dewpoints have fallen
into the mid 60s from Kenansville to Fayetteville to Rockingham,
and some of this drier air should bleed into the area
overnight. Updates early this evening focused on reducing rain
chances this evening (particularly across SE North Carolina) and
showing a faster onset of northeasterly winds. The latest HRRR
appears very reasonable currently. Discussion from 300 PM
follows...

The cold front has shifted into the southern 1/3 of the
forecast area. Models continue to show it shifting southward to
a location south of our area on Thursday.

The convection has formed in two broken lines along boundaries and
is moving south-southeast. The convection is expected to continue
throughout the late evening hours. As dry air aloft moves into the
northern 2/3 of the area the convection for Thursday is expected to
be confined to a line mainly south of Myrtle Beach to just south of
Florence.

Lows tonight are expected to fall into the lower 70s inland to the
middle 70s along the coast. Highs on Thursday will reach into the
upper 80s to near 90 inland to the middle 80s at the beaches.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 315 PM Wednesday...Latest guidance suggests the frontal
boundary will be quasi-stationary along the Carolina coast Thursday
night and Friday. A wave of low pressure is expected to develop
Thursday evening off the southern SC coast and lift north to the
Outer Banks of NC by Friday afternoon. This will keep the highest
PoPs through the period focused along the coast, trailing off to
slight chance west of the I-95 corridor. The front may move inland
across the forecast area Friday night, but the bulk of moisture will
be shunted offshore as a 500 mb closed low drops into the Ohio River
valley. Clouds and northeast surface flow will keep temperatures a
few degrees below climo through this period.

&&

.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 315 PM Wednesday...GFS/ECMWF very similar with development of
mid/upper low pressure across the OH valley during Saturday. Both
drop this feature southward to near AL or GA Monday and the central
Gulf Coast during Tuesday. As a result, a higher precipitable water
environment will likely become focused across the Carolinas with an
increasing potential for showers and thunderstorms each day through
the early part of next week. The increased cloud cover and southerly
flow will support above normal low temperatures each night and
slightly cooler than normal highs each day.

&&

.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 00Z...VFR through the period. Showers near KILM will decrease
by 01Z. Cloud cover will become scattered by midnight. Although
winds will be light and low levels are moist, expect wind speeds to
increase enough by midnight to inhibit fog formation. VFR
Thursday with ENE-E winds around 10 kt.

Extended Outlook...Occasional MVFR to IFR conditions due to
scattered to numerous showers and TSTMs Friday through Monday.

&&

.MARINE...
NEAR TERM /THROUGH THURSDAY/...
As of 945 PM Wednesday...Northeast winds have begun to increase
north of Cape Fear, and should spread beyond Cape Fear to the
Grand Strand and Georgetown vicinity overnight as the surface
cold front continues to sink southward. Only minor changes were
made to the forecast with this late evening update. Discussion
from 645 PM follows...

Thunderstorms this afternoon have thinned out in coverage, but
remain active near Southport, Bald Head Island, and also 20-40
miles east of Georgetown, SC. The trend overnight should be for
convective activity to largely end north of Cape Fear, with
scattered showers and perhaps a thunderstorm offshore of Myrtle
Beach or Georgetown. A cold front has been pushed southward by
thunderstorm activity from around the Santee River entrance to
near Frying Pan Shoals buoy. Models are unanimous that the front
will continue to shift farther south overnight, with east to
northeast winds increasing to 10-15 knots, strongest near Cape
Fear. Seas currently 2-4 feet will change little in height
overnight, but could begin to shift more toward the shorter end
of the wave period spectrum due to increasing wind speeds.
Discussion from 300 PM follows...

A cold front has shifted just south of Little River and will
continue sliding south of the coastal waters overnight. Winds
will become northeast at 10 to 15 knots behind this front and
will become easterly by the end of Thursday. Seas are running 2
to 4 feet this afternoon with a southwest to west fetch. Seas
are expected to fall to 2 to 3 feet before increasing to 3 to 4
feet by Thursday with the northeast flow.

SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
As of 315 PM Wednesday...A frontal boundary will be located just
south of the waters Thursday evening, and lift slowly northward
through the period as a wave of low pressure develops off the SC
coast. The low will lift north to the Outer Banks by Friday
afternoon. Winds are expected to be directed onshore Thursday night,
then become variable Friday as the low moves south to north across
the waters. By Friday night, southwesterlies should develop in the
wake of the low as the frontal boundary shifts northward. With the
frontal boundary and low pressure impacting the waters through the
period, numerous showers and thunderstorms are expected.

LONG TERM /SATURDAY THROUGH MONDAY/...
As of 315 PM Wednesday...A southwesterly fetch is expected to
increase during Saturday with areas of low pressure found across
the eastern U.S. and high pressure far offshore. The fetch could
carry into the first part of next week resulting in a prolonged
period of Small Craft conditions. Seas will likely average 4-6 ft
which is not a typical mid-July sea state.

&&

.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.

&&

$$

SYNOPSIS...MBB
NEAR TERM...TRA/DRH
SHORT TERM...III
LONG TERM...MBB
AVIATION...MRR



Area Forecast Discussion

National Weather Service Lincoln IL

 904 PM CDT Wed Jul 18 2018

.UPDATE...
Issued at 903 PM CDT Wed Jul 18 2018

A strong jetstream aloft will cause a trough to dig faster east-
southeastward into the mid-Mississippi valley region overnight,
with associated thunderstorms spreading into the area. Latest
HRRR and nam-nest models bring some thunderstorm activity into
Schuyler county shortly after midnight, and spread it toward the
Illinois River valley by dawn. Have therefore increased PoPs in
the overnight period in this area. Otherwise, a relatively cool
night on track with lows near 60 from around I-55 eastward, and
low 60s to the west.

&&

.SHORT TERM...(This evening through Thursday)
ISSUED AT 210 PM CDT Wed Jul 18 2018

High pressure located over the central Great Lakes will continue
to provide seasonable temperatures and humidity this afternoon and
into tonight.

Clouds will gradually increase tonight, as the high drifts east
and a trough approaches from the upper Midwest. Scattered
convection should develop Thursday morning as the trough moves
into the area, with the best chance of precipitation located west
of I-55. Moisture and instability will gradually increase through
the afternoon and evening. While some differences exist between
forecast guidance, models suggest a northwest-southeast oriented
instability gradient located over the CWA. With MUCAPE values
approaching 1500-2500 J/kg... and bulk shear values exceeding
30kts... at least a marginal severe threat is likely if convection
can develop.

.LONG TERM...(Thursday night through Wednesday)
ISSUED AT 210 PM CDT Wed Jul 18 2018

Biggest concerns for this period come Thursday night through
Friday afternoon as a cold front passes through Illinois. Some
scattered convection is likely at the start of the period as
instability continues to build eastward, with thunderstorms
likely through Thursday night. A marginal severe threat may
continue through the overnight hours given modest instability and
shear.

Forecast guidance has sped up the timing of the cold front, which
is now expected to pass late Friday morning/early Friday
afternoon. Scattered strong to severe storms may develop ahead of
this cold front... though details are hard to work out. Best
chances for storms will be in our far southeast, where better
instability and shear will be in place.

A few showers are expected this weekend through Wednesday as an
upper level low stalls out over the Ohio Valley. Best chances for
rain will be across the eastern half of the state. The upper low
will gradually weaken before a ridge begins to build back into the
area by mid-week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 644 PM CDT Wed Jul 18 2018

Early morning thunderstorms in the Mississippi Valley region may
migrate as far east as the I-55 corridor by late morning Thursday,
but VFR conditions are expected for the central IL terminals until
15Z. At that point, have included VCTS at KSPI, KPIA, and KBMI
although explicit timing of thunderstorms is not possible at this
point. KDEC-KCMI are expected to remain east of the thunderstorm
activity through 00Z. Any thunderstorms will have the potential
for strong gusty winds and localized IFR/MVFR conditions. Winds
E-NE up to 8 kts overnight, becoming SE 8-12 kts after 15Z.


&&

.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

UPDATE...37
SHORT TERM...Hiris/Smith
LONG TERM...Hiris/Smith
AVIATION...37



Area Forecast Discussion

National Weather Service Omaha/Valley NE

 715 PM CDT Wed Jul 18 2018

.SHORT TERM...(Tonight through Saturday)
Issued at 403 PM CDT Wed Jul 18 2018

Main forecast problem is severe weather overnight.

Closed upper low is forecast to move southeast into the Mid
Mississippi Valley tonight. Airmass is unstable south of a
northwest-southeast warm front. Latest ML CAPE values were between
1000 to 1500 J/Kg. A north-south oriented surface trough over
north central Nebraska is forecast to move slowly eastward during
the evening. 0-6 Km bulk shear at 20Z is 35 to 50 knots over
eastern Nebraska.

Believe the scenario will be isolated storms, most likely
Supercells, to occur in northeast Nebraska during the early
evening. Damaging winds and an isolated tornado is possible.

Then later on this evening, a complex of severe thunderstorms with
damaging wind threat is expected to develop over northeast
Nebraska after 03Z and move southeast across eastern Nebraska and
southwest Iowa. HRRR model forecasts that the complex will be
through eastern Nebraska and southwest Iowa by 11 to 12Z.

After this complex moves through, dry weather is forecast through
Saturday as high pressure moves in.

.LONG TERM...(Saturday night through Wednesday)
Issued at 403 PM CDT Wed Jul 18 2018

Below normal temperatures, with highs in the lower 80s is
forecast. Another chance of thunderstorms is on Sunday night into
Monday morning as a weak cold front moves southeast. This may only
affect western portions of our CWA. The next system with more
widespread thunderstorm activity will be next Wednesday as another
cold front moves southeast in northwest upper flow.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 715 PM CDT Wed Jul 18 2018

Main aviation concern during the TAF period is the coverage and
evolution of strong to severe thunderstorms that currently are
ongoing northwest of KOFK. Isolated convection is expected to
congeal into linear cluster of severe storms and then spread
southeast across eastern Nebraska late evening and overnight. Timing
into KOFK around 03z, with potential impact through 07z.  Right now,
looks like storms will not arrive in vicinity of KOMA until 07-08z,
and will persist through 10-11 UTC.  Timing into Lincoln 08-09z,
with impact through 12z. Ceilings with storms will drop to low
VFR or high end MVFR.


&&

.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&

$$

SHORT TERM...Smith
LONG TERM...Smith
AVIATION...Fortin



Area Forecast Discussion...CORRECTED

National Weather Service Pueblo CO

 302 PM MDT Wed Jul 18 2018

.SHORT TERM...(This evening through Thursday)
Issued at 243 PM MDT Wed Jul 18 2018

Drier air in the mid levels was spreading across the state this
afternoon under nwly flow aloft, while n-nwly surface winds have
begun to lower surface dewpoints as well. Starting to see some very
isolated convection develop over wrn CO and nwrn NM as of 2030z, so
will leave some very low pops in place for the higher peaks of the
Sangres and San Juans into early evening, though coverage/intensity
of any tsra will be sparse/weak. Still some modest instability along
the KS border late this afternoon, though better instability and low
level moisture convergence lie farther to the north and east of the
region over KS. Past few runs of the HRRR and other mesoscale models
haven`t indicated any convection in CO this evening, so will taper
back pops over the plains to just a sliver of isolated near the
border prior to 00z.  Clouds then clear overnight with seasonably
mild temps.

Center of upper level high pressure drifts eastward along the CO/NM
border on Thu, with hot temps across the region as mid level
temps/heights peak. Should see readings well above 100f along the
lower Ark Valley, with 80s/90s widespread elsewhere. Air mass
continues to slowly dry under n-nwly surface/mid-level flow, and
suspect at best only very isolated/weak/mainly dry convection over
the higher peaks in the afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 243 PM MDT Wed Jul 18 2018

After a couple of days of hot and relatively dry weather, rain
chances will be on the increase once again starting this weekend
and especially into early next week. Monsoon moisture will once
again be on the increase as early as Friday along the contdvd and
across the entire region for the weekend into early next week.

For Friday, it will be hot once again with max temps on the plains
aoa 100F along the lower ark rvr valley and 90s over the remainder
of the plains. Upper 80s will occur in the valleys with 70 mtns.
Showers should be on the upswing across the contdvd as moisture
increases.

For the weekend, moisture increases all regions, although I really
do not see any noticeable forcing on the plains, and showers and
storms over the lower elevations may be isolated at best. Over the
mtns, scattered to likely pops are forecasted. Some of this rain may
be locally heavy, with the attended threats of flash flooding and
rockslides.

From late Sunday night into early next week, showers and storms
should become widespread all regions a a front will come down the
plains as early as Sunday night, and this will be the needed forcing
to get storms going over the plains. flash flooding will become more
a concern this period, especially urban areas and east slopes of the
mtns/burn scar regions.

A drier trend will likely start by mid week. /Hodanish

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 243 PM MDT Wed Jul 18 2018

VFR conditions will continue at all taf sites tonight and Thursday,
as drier spreads south across Colorado. Any convection this evening
and Thursday afternoon will be very isolated and high base, with
tsra remaining over the higher terrain.

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...PETERSEN
LONG TERM...HODANISH
AVIATION...PETERSEN



Area Forecast Discussion

National Weather Service Las Vegas NV

 225 PM PDT Wed Jul 18 2018

.SYNOPSIS...Moist and unstable air will remain over the region
through the end of the week providing fuel for afternoon
thunderstorms... especially over the mountains. Early next week, a
heatwave will be building with very hot temperatures expected.
&&

.SHORT TERM...through Saturday.

Thunderstorms in the forecast area have been confined to the Spring
Mountains and central Nevada early this afternoon. Elsewhere,
convection has been slow to develop in spite of Pwat values over 1.5
inches from Clark County southward and CAPE Values of 1500-2000
J/kg. Deep easterly steering flow behind the inverted trough moving
across southern California will bring storms that develop over the
Mogollon Rim into at least Mohave County...and possibly the Colorado
River Valley and southern Clark County this evening. Conditions are
less favorable for any storms that develop over Lincoln/northern
Mohave counties to head into northeast or central Clark County this
evening, but it cannot be completely ruled out as cold pools and
outflow boundaries begin to influence convection late this afternoon
and evening. So, will leave a slight chance of thunderstorms
mentioned in the forecast. The HRRR has been indicating the storms
will mainly be confined to Mohave County this evening.

The ridge centered over central California and the Great Basin is
forecast to migrate over the Four Corners Region Thursday and toward
the Texas Panhandle Friday and Saturday. This will lead to lower
temperatures across Inyo County and central Nevada...diminishing
heat impacts going into the weekend. Also, steering flow will become
southerly for any convection that gets going Thursday into the
weekend. This will shut down the potential for late evening storms
to move into southern Nevada from the northeast like we have seen a
few times over the past week. Moist and unstable air already in
place will not be flushing out, but we should see a slight decrease
in thunderstorm development from west to east the next few days over
southeast California and southern Nevada. Temperatures will hover
near normal.

.LONG TERM...Sunday through Wednesday.

Strong ridge to our east progged to shift westward over Arizona
early next week. Lingering moisture combined with daytime heating
will still allow for thunderstorms to develop mainly along higher
terrain through the weekend. The westward propagation of the high
will increase temps and continue to keep thunderstorms chances
mainly focused over the higher terrain. In the coming days, likely
need to start considering an Excessive Heat Watch for Tuesday and
beyond.
&&

.AVIATION...For McCarran...Outside of convective influence, expect
generally light winds below 10 knots favoring an east-southeast
direction turning to the south-southwest this evening. Thunderstorms
will continue to be possible on the surrounding higher terrain, but
the probability thunderstorms and associated outflow affecting the
terminal is low. CIGs should remain above 10k feet.

For the rest of southern Nevada, northwest Arizona and southeast
California...Outside of thunderstorm influences, winds will follow
diurnal trends with speeds of 5-15 knots. CIGs at or above 10k feet
in general but CIGs may drop to 5-7 k feet in shower and storms.
Isolated to scattered thunderstorms through this evening will
produce gusty and erratic outflow winds. Although, most of the
thunderstorm activity should remain over the higher terrain, it is
possible storms will move into the valleys.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

$$

SHORT TERM...Adair
LONG TERM...Pierce
AVIATION...Salmen


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