Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/05/18

See below for an aviation forecast discussion for the 00Z TAFs.

.SHORT TERM...(This Evening through Wednesday Afternoon)
Issued at 322 PM CDT Tue Sep 4 2018

Cold front has made its way to the James Valley this afternoon while
a short wave trough was shearing northeastward out of Nebraska.
Therefore, showers and storms were beginning to expand on radar and
this should continue into the early evening across mainly the
eastern cwa. This lift and subsequent showers/storms will quickly
end through the late evening as the cold front moves east.
Otherwise, canadian air will be making its way into the region
through tonight and encompass the area through Wednesday. Expect
sunny skies, much lower humidity, less winds, and cooler
temperatures on Wednesday. Temperatures will be 5 to maybe 10
degrees below normal in the upper 60s and lower 70s for highs.

.LONG TERM...(Wednesday Evening through Tuesday)
Issued at 322 PM CDT Tue Sep 4 2018

Surface high pressure will scoot across the region just to our north
Wednesday night, with the center of it over northern MN by 12Z
Thursday. Although, there will still be enough influence of this
high over the eastern CWA to bring light winds and mostly clear
skies. Have therefore dropped lows tomorrow night a few degrees over
the eastern CWA, more towards MET/MAV numbers - and bottomed out
KABR as well.

A dry pattern looks to set up from middle week into the first part
of the weekend. It appears there will be a period of a fairly tight
pressure gradient Friday and Saturday, so have increased wind speeds
above that of SuperBlend, which are typically too low in these
scenarios. Went more towards MOS values. Precipitation chances
don`t enter the forecast again until the latter half of the weekend
when it appears shortwave energy will be tracking across the area.
Of course this far out, there are timing issues to deal with, so
have left inherited POPs alone for right now.

.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
Issued at 638 PM CDT Tue Sep 4 2018

A cold front is just about to clear KATY. The low level cold air
advection and dry air advection is working to scour out the "sub-
VFR" low clouds, with just a few more hours of sub-VFR cloud
potential at KPIR and KATY. KABR/KMBG should be in a VFR flying
condition for the next 24 hours, with KPIR/KATY joining them by
06Z. There is still the potential for a stray shower or
thunderstorm to move through KATY terminal airspace for the next
hour or so, and then KATY should be joining KPIR/KMBG and KABR in
a dry TAF valid period as stable/dry surface high pressure builds
in from the north.

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

UPDATE...Dorn
SHORT TERM...Mohr
LONG TERM...TMT
AVIATION...Dorn

Area Forecast Discussion

National Weather Service Birmingham AL

801 PM CDT Tue Sep 4 2018

.UPDATE...
MESOSCALE UPDATE.

.SHORT TERM...

The forecast remains on track with only minor adjustments to rain
chances.

The latest radar depiction from MOB/Mosaic has Gordon circulation
showing up south of Fort Morgan early this evening. Some banding
features have pushed northward into southern Alabama and have
interacted with a few convergent boundaries in the easterly flow.
NHC`s latest Advisory has Gordon at 70 mph and continuing on its
northwest course. Gordon will make landfall later tonight along
the central Gulf Coast.

SPC`s RAP analysis has the boundary layer starting to stabilize
over Central Alabama with SBCAPE dropping to 1000 or less,
although there is still a bit higher MLCAPE values around. BULK
Shear and Helicity values continue to remain highest south of
Central Alabama. A few storms tried to spin earlier but since have
weakened. There was quite a moisture gradient depicted between
north and south Alabama, with equal differences in shear values.

Typical tropical systems contract the strongest rain bands toward
the center at night. But we also have this system interacting
with land overnight. The good thing here is that the course
appears to be non deviating and the strength is forecast to remain
nearly the same before weakening after landfall. Model guidance
has been consistent too with much of the convection on the north
and east side of the overall circulation.

Similar to the previous forecast, the non-zero tornado threat
overnight into Wednesday still looks rather low. SPC has parts of
southwest and west central Alabama in a Marginal outlook. Will
continue to hold off advertising this threat until landfall and
see how the shear is affected. Wind gust potential between this
low southwest and the high off to the northeast will increase the
gradient wind potential. This also appears to remain below and
advisory criteria at this time. Our southwest counties can
tolerate some decent rainfall and flooding is also not anticipated
at this time.

Previous short-term discussion:Through Wednesday afternoon.

Tropical Storm Gordon is behaving with respect to the forecast
track, and no significant changes were made to the short term
portion of our forecast. Showers should continue develop on the
outskirts of Gordon this afternoon, mainly across our southern
counties. Some of the stronger cells could contain lightning, and
we may have to monitor any cells with rotation as the edge of the
stronger wind field brushes our far southern counties. As Gordon
moves ashore tonight, the swath of heaviest rain should remain
southwest of our forecast area. However, bands on the eastern
side of Gordon should be far enough east to affect our western
areas through Wednesday afternoon. If Gordon tracks more toward
the eastern edge of model guidance, this would place stronger
winds aloft over our western counties, resulting in a non-zero
tornado threat Wednesday morning into Wednesday afternoon.
Confidence is too low to mention this potential in the HWO.

.LONG TERM...
Wednesday Evening and Thursday.

The evening and overnight hours on Wednesday will likely include
lingering effects from Gordon as tropical moisture remains in
place across our CWA. PW values could still range ~2.2" in
counties west of I-65, particularly near the MS/AL border, as
central Alabama becomes wedged between this moist airmass and
drier air to our east via upper-level ridging. This anticyclonic
feature has been positioned across the eastern US and will orient
a west-east moisture gradient across the state as mean RH values
continue to drop Thursday afternoon. With southerly flow now in
place, diurnal heating should spark off scattered thunderstorms
after ~18Z and continue into the evening hours. Best PoPs will
remain in the west/southwest where the best moisture content
remains. The eastern part of the forecast area will be drier
overall with PWs ~1.6", and exhibit mostly sunny skies Thursday.
Still expecting seasonally normal temperatures with highs in the
upper 80s and lower 90s.

Friday through Sunday.

By Friday, Gordon should have little impact on our weather as
remnants should continue to head northwest towards the Missouri
Valley. Ridging along the East Coast will struggle to be as
prominent, though will persist overall. The Polar Jet, well into
Canada at this time, tries to move a bit southward along a low
amplitude trough approaching Nova Scotia and weakens the
anticyclone between this and a westward moving upper-level low
currently south of Bermuda. We should see a drier day on Friday
(20% PoPs) as deep layer moisture remains low within southeasterly
flow with no significant forcing for ascent. Have slightly
increased PoPs for the weekend as result of better moisture values
via a transition to southerly/southwesterly flow on Saturday and
into Sunday to 30 and 40 percent, respectively. This develops
ahead of a trough axis moving across the Great Plains which
transports any Gordon remnants to the northeast through the Great
Lakes region by the end of the weekend. Overall, diurnally forced
afternoon showers and thunderstorms will dictate our precip
chances through this period.

Monday and Tuesday.

Upper and mid-level flow across our area and the southeastern
CONUS remains very weak throughout the long-term. The Polar Jet
stays well to our north, though some smaller/weaker shortwave
features could move across the US and help to enhance storms
activity. Upper-level ridging makes an attempt to build across the
West Coast/Desert Southwest after the weekend, but flow aloft
looks to stay mainly deamplified and zonal across the country.
Thus, generally keeping chance PoPs for afternoon scattered
convection as there will be no reasonable changes in our airmass
throughout the period and sufficient boundary layer moisture
remains in place. High and low temperatures should remain around
our climatological norms as we head into the next work week with
no significant weather impacting our area at this time.

40/Sizemore

.AVIATION...
00Z TAF Discussion.

Tropical Storm Gordon tracking northeast and should make landfall
along the Mississippi Coast later this evening. Scattered showers
and thunderstorms on the northeast quadrant of Gordon will impact
south Alabama thru the overnight hours. VCTS will impact KMGM
thru 01z, with mainly showers thru the remainder of the night
impacting KTOI, KMGM, KTCL. Once Gordon moves into southern
Mississippi, showers and thunderstorms will increase in coverage
on the eastern side of the weakening system, mainly impacting
areas west of I-65. Outside convection, no cig or vsby issues thru
06z. Low cigs will likely impact all Central Alabama sites
starting arnd 06z at KTOI and spreading northwest thru 12z. IFR
cigs will likely be confined to KTOI, with cigs 1000-1500 feet agl
at other sites. Cigs will slowly rise after 14z, becoming VFR by
18z.

58/rose

.FIRE WEATHER...

Highest rain chances will be across southern portions of the area
today, shifting towards western portions of the area late tonight
through Thursday as Gordon passes southwest of the area. There
are no fire weather concerns at this time.

.PRELIMINARY POINT TEMPS/POPS...
Gadsden 73 88 71 90 70 / 30 20 10 30 10
Anniston 73 88 71 90 70 / 40 20 10 30 0
Birmingham 74 86 72 91 72 / 30 50 20 30 10
Tuscaloosa 75 86 72 90 72 / 50 80 30 40 20
Calera 73 85 71 88 71 / 50 60 20 30 10
Auburn 72 86 71 87 70 / 40 30 10 30 0
Montgomery 74 87 72 90 72 / 60 70 20 30 10
Troy 73 87 71 89 70 / 50 60 10 30 10

.BMX WATCHES/WARNINGS/ADVISORIES/...
None.

Area Forecast Discussion

National Weather Service Cheyenne WY

327 PM MDT Tue Sep 4 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 302 PM MDT Tue Sep 4 2018

Main focus for the next 24 hours will center on the fog
potential overnight and early Wednesday morning for the Laramie
Mountain Range Summit area. Fog, some possibly dense could cause
travel impacts along I-80 between Cheyenne and Laramie overnight.
cooler temperatures expected tomorrow with more clouds and higher
terrain showers expected.

Isolated showers and thunderstorms are occurring across the higher
terrain of the Snowy Range this afternoon as a nebulous shortwave
trough exists across the Rocky Mountain Range with just enough
help from surface instability near 500 J/Kg. This activity should
decrease in coverage through the late evening and overnight as
boundary layer cools. A weak cold front passed through the region
this morning with north winds as a result this afternoon. The
beginnings of post-frontal stratus are appearing in the northern
Panhandle and as we cool through the overnight, this stratus layer
should advance southward across much of the High Plains of WY/NE.
Winds will pivot more easterly and with upslope flow in a cooler
and more saturated environment, areas of fog and low clouds look
likely up against and in the Laramie Range. Higher elevations of
I-80 near the summit could experience reduced visibilities from
3am to 9am. Will need to monitor this situation closely for a
dense fog advisory.

Clouds will remain intact much longer Wednesday and thus a cooler
day is expected across the High Plains. Skies will be more clear
farther west and the combination of greater instability and a
more focused shortwave trough should allow for another round of
showers and thunderstorms over the Sierra Madre and Snowy Ranges
in the afternoon.

.LONG TERM...(Thursday through Monday)
Issued at 209 AM MDT Tue Sep 4 2018

Not much change from the previous long term forecast. A wavy
Frontal zone and broad upper level trough will continue to linger
over the area Friday and Saturday before an area of high pressure
moves across southern California. Guidance is not well established
on the specifics of the forecast beyond days 1 and 2.
Temperatures are likely to fluctuate given the presence of the
frontal zone and increased likelihood of showers and
thunderstorms. Cold front that will move through Saturday will
likely bring cooler temperatures through the weekend and the
start of the new week. Rain chances are also likely to increase in
the post frontal upslope airmass.

Next Week zonal flow develops bringing a few shortwave troughs
overhead and continuing the more active period. Guidance is not
convergent on any particular solution, thus, forecast confidence
is low. Climatology and the latest guidance does however suggest a
more cool and wet period with rounds of showers and thunderstorms
and below average temperatures each day.

.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1127 AM MDT Tue Sep 4 2018

Low ceilings are still rising across the NE Panhandle TAF sites
and should see general improvement back to VFR this afternoon.
Other concern for this afternoon will be the development of
showers and thunderstorms mainly east of KLAR. For the overnight
period, the RAP and SREF have been showing low ceilings across the
NE Panhandle again and between KLAR and KCYS. MVFR to IFR ceilings possible
with further refinement in later forecast.

.FIRE WEATHER...
Issued at 302 PM MDT Tue Sep 4 2018

Gusty north winds are occurring this afternoon after the passage
of a weak cold front but relative humidity values remain elevated
in the 30 and 40 percentiles with the small exception of far
southwest Carbon County. Values there are near or below 20% but
winds are much calmer at or below 10 mph.

Limited fire weather conditions will continue through the next
several days as southeast winds return Wednesday and keep
moisture content high while winds will remain below critical
thresholds. Scattered showers and thunderstorms will be of
concern over the higher terrain Wednesday and lightning ignitions
will need to be monitored for given the drying fuels as energy
release component values start to climb above normal once again.

.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&

SHORT TERM...JSA
LONG TERM...AL
AVIATION...WM
FIRE WEATHER...JSA

Area Forecast Discussion

National Weather Service Dodge City KS

508 PM CDT Tue Sep 4 2018

...Updated Aviation...

.UPDATE...
Issued at 341 PM CDT Tue Sep 4 2018

Given radar trends, with training, heavy rain producing
thunderstorms from Great Bend down to the NE Texas panhandle,
have issued another flash flood watch for the eastern CWA
(Barber, Comanche, Edwards, Kiowa, Pawnee, Pratt, Rush, Stafford).
The watch will be valid through 7 am Wednesday. Obviously, many
areas in these zones are saturated or flooded, and the potential
for dangerous runoff is very real as thunderstorms continue to
train north.

.SHORT TERM...(This afternoon through Wednesday)
Issued at 1143 AM CDT Tue Sep 4 2018

Southerly moisture plume continues over SW KS as of midday,
although the radar is clear of echoes, and satellite imagery
indicates more breaks in the cloud cover compared to yesterday.
The added insolation will yield CAPE upwards of 2000 J/kg late
this afternoon, and scattered convective redevelopment will occur.
The latest HRRR iterations favor this happening across the
western zones after 4 pm, west of US 83. This activity will likely
drift eastward to at least US 83 through this evening.

A more organized convective cluster is expected this evening and
tonight across NW Kansas, along an advancing cold frontal
boundary. 12z NAM suggests the majority of this convection will
remain in NW Kansas (WFO Goodland`s CWA), before the convective
remnants drift south with the front late tonight or early
Wednesday. Maintained higher pops and the flash flood watch for
the northern zones through tonight, but confidence is low.
12z NAM, HRRR and various other CAMs keep most of the heavy rain
and flooding potential north of our CWA. With time tonight, the
cold front will sag south, with a shift to N/NE winds of
10-20 mph. At least some shower activity and isolated thunder
will accompany the frontal passage, as well as persist behind it
into Wednesday morning. Stratus and/or fog will again reestablish
Wednesday morning, with low ceilings and areas of reduced
visibility.

Maintained scattered rain showers and isolated thunder in the
grids for Wednesday, in the cool cloudy post frontal airmass. Kept
thunder mention isolated with little CAPE and a cool stable
boundary layer. Temperatures on Wednesday will clearly be below
normal; the question is how much. Forecasting afternoon highs in
the 70s for areas along and north of US 50, with lower 80s
confined to the Oklahoma border. Cool NE winds and cool advection
will combine with persistent stratus, such that northern counties
may struggle into the lower 70s. If stratus persists daylight
Wednesday as the NAM suggests, than clearly the coldest NAM
solution will be correct. Cool surface high pressure ridge axis
will continue to build south into SW KS through Wednesday evening.
This evolution will eliminate surface-based CAPE, and greatly limit
elevated instability, such that the prospects for thunderstorms and
further flooding will be greatly reduced.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 145 PM CDT Tue Sep 4 2018

The cloudy, cool wet weather pattern will persist Thursday and
Friday, with limited sunshine, afternoon temperatures well below
normal, and scattered showers and isolated thunder. As the
previous forecast shift mentioned, instability (even elevated)
will be limited to nil during much of this time. Still, isentropic
lift over the cool stable boundary layer warrants scattered/chance
category pops that the model blends generate. With the lack of
deep convection, the threat of flooding is expected to end.
Thursday looks particularly cool, as 12z NAM/ECMWF depict strong
high pressure ridging from eastern Nebraska wedging into SW KS.
Models suggest stratus and NE winds of 10-15 mph will persist all
day Thursday, with only lower 70s forecast (mid 70s along the
Oklahoma border). 12z MET/MAV guidance only have a high of 72 at
Dodge City Thursday (about 15 degrees below normal). Clouds,
NE winds, and cool surface ridging will hold firm through Friday,
with more pleasantly mild temperatures and free air conditioning.

12z ECMWF consistently depicts the remnants of tropical cyclone
Gordon in far SE Kansas Saturday morning, recurving into the
westerlies across Missouri Saturday afternoon. Gordon will act as
a catalyst for a weather pattern change for SW KS, as the cyclone
pulls the trough axis east of SW KS, and subsidence encourages
a clearing sky. Dry weather will prevail by the weekend, with
afternoon temperatures returning to the 80s.

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 508 PM CDT Tue Sep 4 2018

Another complicated TAF package, including convective potential, a
frontal passage tonight, and low stratus behind the front through
much of Wednesday. Ongoing convection as of 22z should remain
primarily east of DDC. Additional thunderstorms are expected to
develop this evening mainly west of a GCK-LBL line. Finally,
organized convection is expected north of a GCK-HYS line during
the 03-06z timeframe, along an advancing cold front. Broadbrushed
VCSH/VCTS, given uncertainty of convective placement. The cold
front will sag south through the airports through 12z Wed, with a
shift to N/NE winds of 10-20 kts. Additional showers are likely
with the frontal passage, and persisting behind the front through
Wednesday. MVFR stratus is expected to persist much of the
daylight hours Wednesday at all airports.

.PRELIMINARY POINT TEMPS/POPS...
DDC 66 78 63 74 / 70 50 40 50
GCK 64 76 61 72 / 60 40 40 40
EHA 62 78 58 75 / 40 30 40 40
LBL 65 80 60 75 / 40 30 40 40
HYS 65 73 62 70 / 70 60 40 40
P28 69 83 66 76 / 60 60 40 40

.DDC WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Wednesday morning for KSZ030-031-043-
044-046-065-066-079>081-089-090.

UPDATE...Turner
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Turner

AREA FORECAST DISCUSSION

National Weather Service Eureka CA

237 PM PDT Tue Sep 4 2018

.SYNOPSIS...A very gradual cooling trend is expected through the
end of the week. Increasing coastal cloud cover can also be
expected as the marine layer deepens. No rainfall is forecast for
the foreseeable future.

.DISCUSSION...Today`s weather very closely resemble yesterday`s
as little changes are being observed in the synoptic flow aloft.
Only subtle changes to the broad scale weather pattern will
result in a very gradual cooling trend through the remainder of
the week. These changes will be most felt across northern
areas...particularly interior areas of Humboldt and Del Norte
Counties. This will be due to the passage of series of
progressively stronger cold fronts through the Pacific Northwest,
which will not produce any rain in California but will help to
suppress temperatures. Not only this, but a steadily deepening
marine layer will also help to carry cooler temperatures farther
inland through the end of the week. However, while this cooling
trend will be rather pronounced in these northern areas, this
trend will be much more muted across more southern and interior
areas like Mendocino and Trinity counties, where afternoon high
temperatures will continue to climb into the upper 80s and low 90s
each day for the next week. Conditions along the coast will
remain characteristically mild, and will likely not deviate much
from the low 60s for afternoon highs. There is likely to be an
increase in marine clouds, however, particularly tonight through
the end of the week along the immediate coast. In any case,
little to no rainfall can be expected anywhere for at least the
next week. /BRC/JT

.AVIATION...Similar to yesterday`s weather conditions continued
across the North Coast today. Morning stratus at the coast mixed
out in the late morning. However, the Mendocino Coast remained
overcast with marine layer tops 1500-2000 feet. Note: A (MVFR)
smoke layer drifted across the CEC airport in the afternoon. 24
Hour Taf period (thru THU afternoon): Stratus may spill around
Cape Mendocino into Humboldt Bay. Even so, model guidance has
morning LIFR/IFR conditions with even lower CIGS/VIS possible at
the main air terminals.

Interior areas remained mostly VFR other than continued wildfire
smoke affecting some locations. UKI was an exception today as low
clouds advected into the UKI/Russian River Valley where IFR/LIFR
occurred for a couple hours starting around 7 am. HRRR model
guidance indicated low cloud advection breaching the Sonoma and
Mendocino border again Thursday morning. With light south winds at
UKI, expect that some clouds may seep into the airport proper.
Therefore, will go with at least scattered stratus in the A.M.
/TA

.MARINE...Forecast remains on track with gales (north) or hazardous
seas (south) continuing for a few more hours. Advisory level seas
will persist over the southern inner waters into the evening and
over the northern inner waters until around midnight (this has been
extended a few more hours versus the previous forecast). Winds will
continue to gust to near gale force near and downwind from Point
Saint George into this evening. Northerlies will continue through
the work week (with occasional S flow reversal near the coast).
However, speeds are forecast to diminish below advisory criteria by
Wednesday area-wide. N winds over the S outer waters are forecast to
increase again to advisory criteria by late in the week. /SEC

.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 PM PDT this evening for PZZ450-455.

Gale Warning until 5 PM PDT this afternoon for PZZ470.

Hazardous Seas Warning until 5 PM PDT this afternoon for PZZ475.

Visit us at http://www.weather.gov/eureka

For forecast zone information
see the forecast zone map online:
http://www.weather.gov/eureka/zonemap.png

Area Forecast Discussion

National Weather Service Hastings NE

711 PM CDT Tue Sep 4 2018

.SHORT TERM...(This evening through Wednesday)
Issued at 355 PM CDT Tue Sep 4 2018

The rain from last night and this morning has all but moved out
of the local area, and skies have cleared pretty substantially
across portions of central Nebraska. Thunderstorms are currently
developing over west central Nebraska and will generally move
southeastward into the forecast area this evening through tonight.
The SPC introduced a marginal severe risk for these portions of
this area. The RAP indicates 1000-2000 J/kg of CAPE, but the shear
is relatively minimal. This would be supportive of "pulse" type
and multicell storms, and a few could have strong to marginally
severe wind gusts.

The flash flood watch was extended earlier today, as models bring
at least some of these thunderstorms into the southeastern
portions of the forecast area that has received 3-7" over the
past 3 days. In these areas, even 1-2" could lead to additional
flooding concerns.

The passage of the upper trough and surface front will lead to a
drying trend through the day on Wednesday, although we could still
see a few showers redevelop across our southern areas during the
afternoon and evening.

Stratus and northeasterly winds are expected to limit high
temperatures to the upper 60s and low 70s on Wednesday.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 355 PM CDT Tue Sep 4 2018

Drier air should allow low temperatures to dip into the 50s and
low 60s Wednesday night, with only low-end chances for a few
showers or storms in the area.

The forecast remains fairly similar Thursday through Friday, as
the upper level flow pattern remains zonal to slightly
southwesterly. There will be daily chances for showers and storms,
but we shouldn`t see anything as heavy as early in the week.

On Friday night into Saturday morning, another weak trough is
forecast to move through the area. This may bring a bit of an
uptick in precipitation chances again, before generally drying
things out for the rest of Saturday.

The passage of this trough will mark the beginning of a bit of a
warmup as we head into the weekend, highs on Sunday are forecast
to reach the mid 70s to low 80s and should approach 80 degrees
Monday and Tuesday. Unfortunately it appears that "pesky" chances
for showers and storms will continue through this period as
well...especially as another trough moves into the area early next
week.

.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 647 PM CDT Tue Sep 4 2018

We`ll have very little surface winds this evening through tonight
and thus will be calling for winds to generally be light and
variable until we see northeasterly winds behind a trough passage
Wednesday morning. Even then the wind will remain light into
Wednesday. We will once again have to watch out for thunderstorms
with heavy rain, which will be scattered across the area this
evening into early Wednesday morning. The best chance for showers
and thunderstorms will be between 9 pm this evening and 7 am
Wednesday. Ceilings will likely fall into the low end MVFR or
possibly IFR range behind the surface trough Wednesday morning.

.GID WATCHES/WARNINGS/ADVISORIES...
NE...Flash Flood Watch through Wednesday afternoon for NEZ064-074>077-
082>087.

KS...Flash Flood Watch through Wednesday afternoon for KSZ005>007-
017>019.

SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Wesely

Area Forecast Discussion

National Weather Service Grand Junction CO

555 PM MDT Tue Sep 4 2018

.SHORT TERM...(Tonight through Wednesday night)
Issued at 255 PM MDT Tue Sep 4 2018

The upper level trough just won`t move and with that, the forecast
won`t change much either. As we`ve been saying all week, the
trough will keep the atmosphere unsettled and as weak disturbances
move through, instability gets released and causes some showers
and thunderstorms to form. H7 winds today were generally out of
the north until you reach the San Juans and then they become south
to southwesterly. This wind shift has kept areas up north drier
than down south and is one of the reasons precipitation has been
favored over the San Juans. This is being borne out today with
radar imagery showing a large swath of showers and storms
generally over the San Juans and areas west. A bit of convection
has fired over the Book Cliffs and central mountains but, so far,
nothing too impressive. Available CAPE is also fairly low across
the area except the San Juans. Everything`s going according to
plan so made some relatively minor changes to the forecast
generally for the overnight hours. The HRRR and NAMNEST showed a
marked decrease in convection so followed suit with the forecast.

Tomorrow, activity looks to increase as all models have picked up
on a small area of circulation moving over the region. Aside from
the disturbance, upper level flow becomes generally southerly
allowing the deeper moisture down south to advect northward. As
this is occurring, CAPE values increase for much of the area
especially over the higher terrain with some maxima over the Flat
Tops, Book Cliffs, and along the Continental Divide noted. Looking
further up in the atmosphere, divergence aloft values are about
the same as we`ve seen lately though areal extent increases across
much of the area. Plenty of ingredients are in place for an uptick
in convection so yet another day of showers and storms expected.

.LONG TERM...(Thursday through Tuesday)
Issued at 255 PM MDT Tue Sep 4 2018

The polar front jet finally gets going during the long term period
as an embedded 120+ kt jet streak approaches the west coast. This
movement will cause the trough to finally start shifting
eastward. However, we`ll still have to deal with some convection
both Thursday and Friday as enough residual moisture will remain
in the atmosphere and will still be worked on by the trough as it
starts getting shunted to the east. High pressure off to our
southwest will start building in over the weekend though passing
disturbances to our north will flatten it. Speaking of, one of
the disturbances may drift overhead Saturday night into Sunday
morning bringing some precipitation to the northern valleys but
confidence not very high at the moment so slight chance PoPs look
good. As the high builds in, temperatures will start increasing
reaching 3 to 5 degrees above normal for much of next week.

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 550 PM MDT Tue Sep 4 2018

Showers with embedded thunderstorms will continue to drift
westward off the higher terrain, generating outflow boundaries and
impacting some TAF sites with gusts to 35 kts at times depending
on where the storms and outflows are tracking. Otherwise, winds
will be fairly light with weak winds aloft. This activity should
continue through about 02Z with VCTS common at TAF sites along and
south of I-70 corridor before dissipating after sunset. Scattered
to broken clouds will linger around as the low pressure trough
remains over the area. Storms are expected to redevelop after 17Z
over the higher terrain again on Wednesday with better coverage
and better chance of some storms impacting the valleys late in the
day. Expect mainly VFR conditions to prevail with occasional MVFR
in heavier showers.

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...None.
UT...None.
&&

SHORT TERM...TGR
LONG TERM...TGR
AVIATION...MDA

Area Forecast Discussion

National Weather Service Green Bay WI

645 PM CDT Tue Sep 4 2018

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Wednesday
Issued at 218 PM CDT Tue Sep 4 2018

The latest RAP analysis and satellite/radar imagery show a warm
front stretching across the Upper Peninsula, and a cold front
extending over far northwest MN and central SD early this
afternoon. Where skies have cleared south of the warm front, temps
have risen into the middle 80s with juicy mid 70s dewpoints.
Plenty of instability within this airmass (SB capes 2000-3000
j/kg) for scattered showers and storms through early this evening.
Not out of the question that a severe weather threat will develop late
this afternoon over parts of central into east-central WI as the
atmosphere continues to destabilize. Damaging winds will be the
main threat with any storms develop. Meanwhile a plume of deep
moisture is extending from the western Gulf to the Upper
Mississippi Valley. Shortwave activity over Nebraska is helping
generate a band of showers and storms within this deep moisture
plume. As this deep moisture interacts with the cold front,
instability, and shortwave activity, severe weather and flash
flood chances are the main forecast concerns.

Tonight...The cold front will slowly move to the southeast into
northwest WI late. Ahead of the front, a shortwave trough over
the Plains and a wave of low pressure will travel northeast across
west-central to north-central WI from late evening through
overnight. A few strong to severe storms are possible early in the
evening to mid-evening as ample diurnal instability interacts
with 25-35 kts of deep layer shear. Central WI has the higher
shear so believe the higher threat of severe weather will occur
there. After this initial period of convection, a large swath of
showers and storms are expected to push into central and north-
central WI late this evening. Strong fgen forcing within the right
entrance region of a jet streak to go along with very good
moisture transport via a 50 kt low level jet will lead to the high
potential of heavy rainfall. Most short range guidance is in good
agreement placing the axis of heavy rainfall from western
Marathon to Florence county, where a 2 to 4 or 3 to 5 inch
rainfall is possible. Issued a flash flood watch earlier this
morning for parts of central and all of north-central WI. Given
the strength of the low level jet and low level helicities
associated with the surface low, may see an isolated damaging wind
threat develop along the southern edge of the heavy rainfall,
where elevated instability above 1000 j/kg will persist through
the overnight hours.

Wednesday...The heavy rainfall will be tapering off and exiting
the area to the northeast and east during the morning hours for
the most part. A few showers may linger into the early afternoon
over east-central WI. With the cloud cover, morning showers and a
north wind, temps will be cooler and range from the upper 60s in
the north to middle 70s south.

.LONG TERM...Wednesday Night Through Tuesday
Issued at 218 PM CDT Tue Sep 4 2018

Relatively quiet weather is anticipated during the extended
period. Canadian high pressure is expected from Wednesday night
through Saturday, along with pleasant, near-normal temperatures.

Forecast confidence is lower later in the weekend. The 00z ECMWF
brought the remnants of Tropical Storm Gordon into the region,
along with a good chance of rain south and east. However, the 12z
ECMWF has fallen more in line with the latest GFS, and keeps the
system well to our south before shunting it off to the east. For
now, will just carry small pops south and east Sunday into Sunday
night, and see how the models trend in upcoming days.

A weak cold front may also bring a small chance of showers to
north central WI Monday into Monday night, but that is a low
confidence proposition too.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 644 PM CDT Tue Sep 4 2018

Scattered showers and thunderstorms will continue across the
region through mid evening, with generally VFR conditions outside
of the precipitation.

Ceilings and visibilities will lower later tonight as a large
area of showers and thunderstorms arrives form the west. IFR
conditions are expected over most of the area from midnight
through 12z or a little later. A cold front will move pass by
around midday tomorrow and be followed by clearing skies during
the afternoon.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Wednesday afternoon for WIZ005-010>013-
018>021-030-031-035-036.

Beach Hazards Statement from 4 AM CDT Wednesday through
Wednesday afternoon for WIZ022-040-050.
&&

SHORT TERM.....MPC
LONG TERM......Kieckbusch
AVIATION.......RDM

AREA FORECAST DISCUSSION

National Weather Service Jackson KY

855 PM EDT Tue Sep 4 2018

.UPDATE...
Issued at 855 PM EDT TUE SEP 4 2018

Precip has died out and a quiet night is expected. Obs have been
blended into the forecast, with no substantive changes.

UPDATE Issued at 527 PM EDT TUE SEP 4 2018

Based on radar trends, have expanded a 20 percent POP over more
of the area for the next hour or two.

.SHORT TERM...(This evening through Wednesday night)
Issued at 330 PM EDT TUE SEP 4 2018

18z sfc analysis shows high pressure in place over eastern
Kentucky with significant ridging aloft. In fact, with the 5h
ridge maxing out overhead this afternoon it appears to have
capped our convective development through the afternoon unlike the
previous days. Cannot rule out a stray shower or storm through
sunset, but coverage will likely be below isolated. The cu field
is much flatter than what we saw yesterday and Sunday even over
the higher southeast terrain with locations well to the west and
northwest seeing the best build up. Have raised PoPs a tad in
these areas on the fringes of the CWA and still allowed for a 15%
PoP in the south through 6 pm but that may be overkill. Anyways,
the heat and humidity are as advertised with readings reaching the
upper 80s and lower 90s again this afternoon while dewpoints are
up in the lower 70s yielding heat indices in the 95 to 100 degree
range many places. Will leave the mention of this (and the small
storm chances) in the HWO for the remainder of the afternoon.
Winds, meanwhile, are mainly light and variable across eastern
Kentucky.

The models remain in good agreement aloft through the short term
portion of the forecast. They all depict the slow breakdown of the
5h ridge over the area through Thursday morning. While far eastern
Kentucky should still be dominated by this ridge, to the west
energy spinning out of the mid levels of Gordon will seep into
the area lowering heights and limiting the suppression of the
anomalous 5h high. With the models in better agreement on this
development this afternoon than 24 hours ago confidence is higher
in at least western parts of the CWA seeing some impact in the
form of increased convective potential - and not necessarily just
during the diurnally favored times. Given the model agreement
have gone with a blend as the starting point with a lean on the
higher resolution HRRR and NAM12 for details.

Sensible weather will feature a scant amount of convection into
the late afternoon before dissipating toward sunset early this
evening along with the bulk of the clouds. For tonight, this will
mean another ridge to valley temperature split - though small due
to the high dewpoints as well as some river valley fog towards
dawn. Without the main protective shield aloft more convection is
expected to develop by midday on Wednesday continuing into the
evening - also limiting the magnitude of the heat - though still
quite warm and humid. The cloud cover and small chances - though
sub 15% - for convection Wednesday night will likely limit the fog
development as well as the temperature differences.

Used the CONSShort and ShortBlend as the starting point for the
forecast grids, per the usual, with some minor temperature
adjustments - warmer Wednesday and slightly cooler in the valleys
tonight. As for PoPs, again adjusted them down outside of the
diurnally favored times - but allowing for up to 30% in the
southwest on Wednesday afternoon - also down from the blend.

.LONG TERM...(Thursday through Tuesday)
Issued at 252 PM EDT TUE SEP 4 2018

Models are in generally good agreement heading into the upcoming
weekend, with lower confidence developing over the weekend and
into next week, especially regarding the remnants of current
tropical storm Gordon. The upper level ridge will continue to
slowly break down into Saturday as the upper level flow starts to
become more zonal over the Ohio river valley. This coincides with
a cold front that will slowly push southward across the region
into Saturday. This frontal zone may or may not reach eastern
Kentucky. However, plenty of surface moisture will continue to
yield increased afternoon/evening shower and storm chances. We
should continue to see relative lulls through the overnight and
early morning hours each day through Saturday.

As the boundary stalls this weekend, exact placement of the
boundary will be key as moisture from the remnants of tropical
storm Gordon start to interact with the boundary. With flow
becoming fairly parallel to the frontal zone, potential for
locally heavy rain will exists in the vicinity of wherever this
front sets up. Models are generally keeping that heavier rain axis
to our north, but any shift southward could lead to more of a
concern. The low center will eventually strengthen again into
early next week with a trough axis working its way across eastern
Kentucky. This may be a slow moving axis as the steering winds are
not all that perpendicular to the boundary. Thus, a local heavy
rain threat could exist with the boundary crossing the area into
next week. The boundary should eventually shift southward by the
middle of next week, but due to the expected slow movement this
could linger around a bit longer. With the increased rain chances
and the ridge breaking down, the warm temperatures we have seen
recently will take a step backwards this weekend into next week.

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
ISSUED AT 855 PM EDT TUE SEP 4 2018

VFR conditions were present at the start of the period. Fog will
develop in valleys containing large streams overnight, and bring
localized VLIFR conditions, but the fog is expected to have
little or no impact at TAF sites. Fog will dissipate on Wednesday
morning, and scattered showers and thunderstorms will develop in
the afternoon. Coverage should be a little bit greater than on
Tuesday, but the probability at any given point/time is not high
enough to warrant inclusion in TAFs.

.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

UPDATE...HAL
SHORT TERM...GREIF
LONG TERM...KAS
AVIATION...HAL