Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/02/19

AREA FORECAST DISCUSSION

National Weather Service Jackson KY

 1103 PM EDT Mon Apr 1 2019

.UPDATE...
Issued at 1102 PM EDT MON APR 1 2019

Have made a couple of updates over the last few hours, loading in
the latest observations to make sure the near term forecast for
temps is on track with the current conditions. Currently we are
still mostly clear outside, with clouds developing well to our SW
across western TN. It is not apparent by the satellite that the
progression of these clouds will allow them to work all the way
into the CWA during the overnight as is currently forecast, unless
new clouds develop on the front edge. If clouds do not fill in as
forecast, this may have some impact on the overnight lows. As of
now the forecast temps are still in good shape, but will need to
continue to monitor as we head through the overnight in case temps
need to be lowered. All updates have been published and sent to
NDFD/web. A new forecast package was sent out to change to
overnight wording. A new NPW and SPS was also sent out to remove
evening start time wording.

UPDATE Issued at 743 PM EDT MON APR 1 2019

Forecast is in good shape so far this evening, with high wispy
clouds and otherwise calm conditions. Loaded in the latest
observations for temps, dew points, and winds to make sure the
near term forecast was on track with the current conditions. Will
continue to monitor temperatures closely as we lose sunlight in
case any adjustments to the lows and overnight diurnal curve are
needed. This could also have some impact on the extent of the
below freezing temps and frost potential. As of now, updates were
not significant enough to warrant any updates to the ongoing
forecast package.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 335 PM EDT MON APR 1 2019

19z sfc analysis shows high pressure passing through the Ohio
Valley. This has kept skies mostly sunny for much of the day
across eastern Kentucky, though a developing wave of low pressure
to the south is pushing some high clouds into the area from the
southwest. Despite the sunshine, temperatures have been slow to
rise - from chilly morning lows - so that at 3 pm they range from
the low 40s northwest to the upper 40s in the southeast.
Dewpoints, meanwhile, are mainly in the teens across the area with
generally northeast winds of 5 to 10 mph.

The models continue to struggle a bit aloft with the southern
stream wave due to pass by to the south of Kentucky late tonight.
The NAM is a tad shallower with this than the GFS and ECMWF.
Either way the core of this wave`s energy will stay south of
eastern Kentucky minimizing its impact for the JKL CWA. The
pattern will then flatten out in the wake of this wave with
northwest flow and slightly depressed 5h heights over Kentucky
into Wednesday morning. With the model uncertainty for tonight`s
wave have favored a blended solution along with a lean toward the
HRRR for near term specifics.

Sensible weather will feature another cool night, but not nearly
as cold as last night. Still a big question as to how quickly the
clouds from the south move in and thicken this evening. This will
affect the temperature drop off following sunset in our western
and southern locations. Further east the thinner clouds should do
little to limit the temperature drop resulting in several hours
of sub freezing temperatures likely in the deeper valleys.
Accordingly, have issued another freeze warning for our northeast
counties (in conjunction with RLX). The questions as to the
ability for frost to form with the increasing clouds limited the
mention of frost to just areas in the freeze warning and the
remainder of the CWA. Therefore an SPS was issued for the rest of
the JKL CWA where the growing season has begun with a potential
for frost highlighted as well as temperatures in the valleys
getting close to freezing in the predawn hours. With the southern
system nearing towards dawn do expect readings to rebound slightly
by 12z for much of the area. Would not be surprised to see a few
sprinkles strafe the southeast border from this system but for now
have kept it dry. A warmer day is expected for Tuesday with highs
near 60 for most of eastern Kentucky under partly cloudy skies.
Some frost will be possible again in the valleys on Tuesday night
as the skies clear out allowing readings to drop into the low to
mid 30s in the valleys to around 40 on the ridges.

The CONSShort and ShortBlend guidance were used to initiate the
grids with some significant ridge to valley temperature
adjustments tonight and Tuesday night. As for PoPs, did keep them
in the single digits or less for the area as that southern wave
passes late tonight - slightly lower than CONSShort.

.LONG TERM...(Wednesday through Monday)
Issued at 300 PM EDT MON APR 1 2019

The long term portion of the forecast will feature a rather
progressive pattern across the United States, with a couple of short
wave troughs affecting eastern KY during the period. It will also be
a warm period with above normal temperatures throughout this portion
of the forecast. At the start of the period surface high pressure
will be over the southern Appalachians, with a mid level southern
stream short wave trough over the southern Rockies. Out ahead of the
mid/upper wave surface low pressure will be developing in the
southern high plains.

Dry warm weather will be on tap for Wednesday, with moisture return
likely to be slow to develop across the area. As the high shifts
southeast Wednesday night, and the short wave trough advances into
the southern plains we will see a gradual increase in moisture
across the area. A cold front will drop south into the southern
Great Lakes and stall over northern parts of the OH valley by
Thursday morning, with the southern plains mid/upper level wave and
associated surface low moving east. There is good agreement that the
short wave trough and associated surface low will weaken as they
move east. This southern stream system will still bring a chance of
showers to the area Thursday night and Friday. However the system
will be weakening, there will be very limited instability, and
convection over the southern MS valley and southeast U.S. will
likely prevent deep moisture flow into our area. Rain may also be
more focused along the stalled front to our north. As a result rain
amounts in our area should be relatively light, with amounts
generally less than 0.40 inch. Thunder chances will also be limited
with the Thursday-Friday system. Will scale back thunder chances to
just Thursday night for the southwest part of the forecast area.

With this first trough passing east by the end of the work week, the
surface front to our north should drop south into our area
temporarily to start the weekend before quickly retreating north in
advance of the next short wave trough. On Saturday we`ll turn our
attention to the next short wave trough in the southern stream
emerging from the southern Rockies. This system looks to take a more
northwesterly track over the weekend into early next week, with
surface low pressure tracking from the southern plains into the
Great Lakes by early next week. Out ahead of this, instability
should increase in our area Saturday and Sunday, with warming
surface temperatures and dewpoints increasing this weekend. As a
result shower chances will continue, and will introduce thunder
chances for Sunday afternoon. By the end of the period a cold front
should be moving through the area, with a potential cool down by the
middle of next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 747 PM EDT MON APR 1 2019

High pressure will dominate the weather through the period, with
VFR skies expected. However, a weak wave will track east out of
the Central Plains tonight bringing increased mid to high level
clouds for east KY later tonight and persisting through much of
the day Tuesday. Expect the nearby high pressure area to keep
winds light and generally out of the north and east overnight,
switching to the southwest generally under 10 kts during the day
tomorrow as the center of high pressure shifts farther east of the
region.

&&

.JKL WATCHES/WARNINGS/ADVISORIES...
Freeze Warning until 9 AM EDT Tuesday for KYZ060-104-106>115-
118>120.

&&

$$

UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...SBH
AVIATION...JMW




Area Forecast Discussion

National Weather Service Raleigh NC

 942 PM EDT Mon Apr 1 2019

.SYNOPSIS...
Chilly high pressure will move off the Mid Atlantic and Northeast
coast tonight. Low pressure will develop off the Georgia coast and
track northeastward along the Carolina coast through Tuesday. High
pressure will build into the area from the southwest Tuesday night
through Wednesday.

&&

.NEAR TERM /THROUGH TONIGHT/...
As of 945 PM Monday...

Evening update: Very little change in the forecast this evening as
numbers are on track based on observations. Modified the onset of
precipitation slightly earlier across the south due to actual
rainfall currently near Charleston, which the high resolution models
don`t have reaching until a couple of hours from now. Otherwise the
previous thinking remains the same and that discussion follows. -
Ellis

Confidence has grown in the precip pattern and coastal surface low
track and evolution, but considerable uncertainty persists regarding
precip type. The mid level shortwave trough over OK/TX early this
afternoon will track E into the Southeast states tonight, with
falling heights late downstream over NC. We`re already seeing
falling surface pressures off the GA coast along the old frontal
zone associated with precip forced in part by passage of an upper
divergence max over N FL and off the Southeast coast, a product of a
WSW upper jet from E NC offshore. The approach of the mid level wave
will further lower surface pressures late, with fairly rapid
cyclogenesis anticipated late tonight just off Hilton Head SC. The
strengthening flow between this low and the surface high shifting E
off the Northeast coast will draw increasing moisture and deepening
moist upglide into SE and extreme S sections of the forecast area
late, although the initially dry subcloud layer (current dewpoints
in the teens to lower 20s) will greatly reduce amounts, particularly
at the onset. Regarding precip type, given the initial dry air
evident both in the low levels and in the 700-600 mb depth, the
strengthening dynamic lift will foster wet bulbing of the profile,
although it remains to be seen if this will be enough to totally
overcome the dry near-surface air, especially well inland beneath
the lingering narrow surface ridge. If so, wet bulbs both at the
surface and just aloft support a potential for a little rain/wet
snow mix in the far SW Piedmont late tonight. But the latest RAP
guidance shows the surface wet bulb rising just above freezing as
the profile zippers down, along with a warm nose aloft near 5C, both
of which would not be conducive for much wintry precip. Plus, latest
4" soil temps are no cooler than 45-50F across our area, and today`s
insolation with a warm early-April sun will likely make the skin
temps too warm for any accumulation. Will include a small chance of
rain/snow mix in the far SW Piedmont late tonight, with a chance of
just rain across the rest of the S, following consensus of model
timing. Skies will trend mostly cloudy to cloudy SSE to NNW through
tonight, with lows in the lower to mid 30s. No freeze products
tonight, as any 32F readings in the far N will likely last only
briefly. -GIH

&&

.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 325 PM Monday...

The models are not in perfect agreement on the precip pattern and
amounts with the low moving up the Carolina coast and related mid
and upper level forcing for ascent, but they`re in a lot better
agreement than yesterday`s runs. Will have categorical pops over
roughly the SE half, tapering to mid range chance pops in the NW
Piedmont. Forecast soundings in this area indicate a possible light
rain/snow mix at onset over the Triad region/Yadkin Valley for a few
hours in the morning. As noted above, the skin and soil temps should
greatly limit the accumulation potential, but the warm nose aloft
may be a bit less prominent and cooler that far NW, bolstering the
wintry weather concern. Will continue to refrain from mentioning any
accumulation at this time, but will closely monitor trends of
observations and high res guidance, along with surface wet bulb
trends as we head into Tue, as the circulation around the low keeps
drawing the cooler/drier air into NW sections. The mid level
shortwave trough will take on a negative tilt and will likely deepen
further as it swings NE through the Carolinas, prompting further
strengthening of the surface low and a westward expansion of
moisture advection N and NW of the low. Expect categorical pops E,
within increasing and gusty surface winds due to the tightening MSLP
gradient, tapering to chance far W, lasting well into the afternoon.
Modified surface high pressure will build in from the SW late in the
day and through Tue night as the surface low heads offshore with
increasing low level NW flow over central NC, so expect a W to E end
to precip and a clearing trend Tue evening and night. After highs
Tue in the mid 40s to lower 50s (near to within a couple degrees of
record low maxes for the date), expect lows Tue night in the lower
to mid 30s, which may prompt another freeze product for a portion of
the forecast area. -GIH

&&

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...
As of 335 PM Monday...

The long term will be characterized by above normal temperatures and
a chance of precipitation Friday into Saturday. The latest runs of
the GEFS, GEPS, and EPS are in high agreement showing above normal
height anomalies (approaching 15 dam) starting Thursday and
continuing through the remainder of the extended. These type of
height anomalies will easily support temperatures 10 to 15 degrees
above normal for this time of year.

Wednesday morning surface high pressure will be centered near
Charleston, SC and slowly drift east offshore. Dry weather will be
in store for the area Wednesday into Thursday as the upper level
disturbance continues to rotate northeast and the corresponding
surface high moves offshore. During the day Thursday 500 mb heights
begin to surge with 850 mb temperatures rising to around 6 degrees
C. This will easily allow highs to rise into the 70s.

Thursday night into Friday morning a weak upper level disturbance
will approach the area from the west. The ECMWF and GFS continue to
advertise slight differences with the wave. The GFS has a stronger
wave across the Great Lakes with very weak PVA washing over central
North Carolina. The ECMWF on the other hand as a weaker wave across
the Great Lakes, but a slightly stronger wave over central North
Carolina (the PV is more compacted). The ECMWF solution generates a
surface low off the North Carolina coast while the GFS only shows a
very weak surface reflection. Not surprisingly, the ECMWF has higher
QPF totals Friday into Saturday than the GFS. The CMC resembles more
of the ECMWF solution. Either way, the chance for precipitation
looks likely Friday into Saturday. Forecast soundings are also
looking much more promising at this time for the chance of thunder.
For now have left the mention out.

The slightly stronger amplification of the CMC and ECMWF solutions
brings a cold front temporarily into the northern zones Friday
morning. If this trend ends up continuing temperatures will have to
be lowered Friday/ Saturday. On the back side of the wave weak
subsidence will take hold with the surface front washing out. The
ECMWF and GFS show weak showers still possible on the back side
though thanks to the stalled boundary.

&&

.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 840 PM Monday...

24 Hour TAF Period: VFR conditions are expected to continue this
evening into the early morning hours of Tuesday. However, a
developing area of low pressure off the coast of GA/FL and S SC
later tonight will track NE along the Carolina coast Tue, spreading
precipitation to its N and W starting around daybreak in southern
portions of central NC, while the low level flow from the ENE ahead
of this low draws increasing low level moisture into the area. The
rain will spread north/northeastward Tuesday morning into the
afternoon, before shifting to the east/northeast of the area by late
afternoon/evening. Snow may mix with the rain at KGSO/KINT during
the morning as well. Otherwise, expect increasing cloud cover this
evening into early Tuesday morning. Winds will also increase as the
surface low approaches and strengthens on Tuesday, with gust of up
to 20 to 25 kts possible for the eastern TAF sites (KFAY/KRWI/RDU).

Outlook: Any sub-VFR conditions will end W to E between 21z and 03z
as the coastal low tracks NE and away from NC, leaving VFR
conditions as high pressure builds in from the SW. VFR conditions
will hold through Thu. Our next storm system moving in from the W
will bring a chance of showers and sub-VFR conditions Thu night and
Fri, perhaps lasting into early Sat morning.

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
None.

&&

$$

SYNOPSIS...Hartfield
NEAR TERM...Ellis/Hartfield
SHORT TERM...Hartfield
LONG TERM...Haines
AVIATION...BSD/Hartfield



Area Forecast Discussion

National Weather Service Reno NV

 749 PM PDT Mon Apr 1 2019

.UPDATE...

Increasing upper level divergence due to a jet nudging into
northern California/Nevada is helping to bring widespread rain
and high elevation snow to the region. This is producing higher
liquid totals than previously anticipated, therefore have
adjusted the forecast to better line up with latest radar trends
and HRRR guidance. Anticipate precipitation chances through the
night, becoming more showery by morning. Snow levels will be above
7500 feet much of the night, but could briefly fall in heavier
precipitation bands. By daybreak, snow could be sticking down to
around 6500-7000 feet, with minor accumulations impacting travel
along Sierra passes. -Dawn

&&

.PREVIOUS DISCUSSION... /Issued 210 PM PDT Mon Apr 1 2019/

SYNOPSIS...

Occasional showers and gusty winds are forecast through this week
as weak to moderate spring storms impact the region. The wettest
periods look to be tonight through Tuesday, and again Friday night.
Temperatures will be generally near early April averages, with
some warming possible later this weekend into early next week.

SHORT TERM...

No major changes were made to the short term forecast, although
we increased precip chances and amounts tonight-Tuesday for much
of west central NV, generally near and east of US-95. Daytime
temperatures near early April averages are projected for the next
few days.

An early spring storm system moving inland near the CA-Oregon
border will bring increased moisture to much of eastern CA-western
NV tonight and Tuesday. While for the Sierra the precip amounts
don`t look too spectacular, for west central NV there is some good
agreement among much of the guidance for a couple waves of
moisture bringing periods of steady light-moderate rain this
evening through Tuesday morning. Then by Tuesday afternoon,
increasing instability associated with the negatively tilted
trough could lead to a few thunderstorms producing brief heavy
rainfall or snow pellets. While isolated lightning strikes are
possible across any portion of eastern CA-western NV, the best
chances for thunder favor west central NV including Lovelock,
Fallon and Hawthorne. Precip totals look to range from 0.10-0.25"
for the urban corridor of western NV southward along US-395 to
Mono County, but heavier amounts between 0.25-0.50" (locally up
to 0.75") are likely from US-95 eastward, and also for the Sierra
northward into western Lassen County.

Snow impacts will be limited to higher elevations as snow levels
generally settle between 7000-7500 feet later tonight into
Tuesday. Impacts would mainly be wet roadways and perhaps some
light slushy accumulations on higher passes. A few inches of snow
are expected for the higher elevations of the Sierra and Carson
Range, with isolated amounts around 8" near the crest.

Periods of breezy winds are expected with gusts 30-35 mph Tuesday
afternoon and evening. The widespread cloud cover should limit
wind duration, and although some moderate chop is likely on the
main lakes, overall conditions look to be just below lake wind
advisory criteria.

For Wednesday, dry weather prevails as a shortwave ridge moves
across CA-NV, with the only possible exception being a few very
light showers brushing across northeast CA.

The next weather system for Thursday-Thursday night looks weaker
compared to the system for tonight-Tuesday, with light rain and
high elevation snow showers mainly for northeast CA and near the
Sierra. Precip amounts look to be 0.10" or less, except for up to
0.25" possible for parts of northeast CA. For western NV, only
trace amounts to a couple hundredths of an inch are expected.
Snow levels will generally range from 6500-7000 feet, but
accumulations will be sparse due to most of the shower activity
occurring in the afternoon. MJD

LONG TERM...Friday through Monday...

The story for the extended remains largely the same: decent spring
storm for Friday afternoon into Saturday morning with typical
impacts including gusty winds, high elevation snow, and valley
rain showers. Plan for impacts to the Sierra passes if you have
travel plans! The rest of the week into next week still holds a
bit of a question mark, but a warm up could be on tap with the
potential for increased snowmelt.

Friday-Saturday Storm: Friday morning will still feature a bit of a
break in the precipitation, but gusty winds will impact the
foothills and mountain areas ahead of the next storm. The main
portion of the storm will push into the Sierra and western Nevada
late Friday afternoon through early Saturday morning. Gusty winds
will increase in the upper terrain and foothills early afternoon,
and will mix down to the lower valleys later in the day. Gusty winds
between 35 to 45 mph will be possible, but the latest GFS soundings
for Friday afternoon do show the potential for some downslope
enhancement. With the strong jet pushing into northern CA/NV, there
may be aviation impacts including wind shear, mountain waves, and
turbulence. Timing of the heaviest precipitation will likely
occur in the northern Sierra Friday evening and overnight. Snow
levels start above 6500-7000 feet, then fall to 6000-6500 feet by
late Saturday morning. Latest simulations continue to show the
snow levels dropping after the bulk of the precipitation has
pushed through, which should limit snow accumulations to higher
terrain of the northern Sierra and northeast California. Liquid
totals range from 0.50" to up to 2" along the crest with the
lower values across the southern Sierra. A third of an inch will
be possible in far western Nevada and the lower valleys of
northeast California; with lesser amounts forecast in the Basin
and Range.

Beyond Saturday the simulations aren`t in outstanding agreement,
but the weather pattern still looks unsettled. The GFS is still
attempting to build a shortwave ridge across the region, but the
ECMWF keeps precipitation chances across the northern portion of
the area through at least Sunday. -Edan

AVIATION...

A series of disturbances are on track to affect area terminals
today through Thursday, with the possibility of another system
affecting the forecast area Friday through this upcoming weekend.

Rain and high mountain snow are likely tonight and Tuesday across
much of eastern CA-western NV. Expect conditions to deteriorate
through this evening, with MVFR conditions expected at Sierra
terminals becoming MVFR/IFR early Tuesday morning as ceilings and
visibility begin to lower. Conditions at western Nevada terminals
will mainly remain VFR through this evening, becoming MVFR at
times late tonight-Tuesday morning, with periods of moderate
rainfall mainly for parts of west central NV. Snow levels will
likely remain above 6500-7000 feet, therefore no accumulating snow
is expected at either KTVL or KTRK. However, light snow may
accumulate at KMMH by early Tuesday morning.

For Tuesday, breezy surface winds can be expected with gusts of
30-35 mph possible east of the Sierra. An area of instability may
develop east of the Sierra, where isolated thunderstorms could
develop. Brief heavy rains and a few lightning strikes may occur
with these cells.

A break will occur Wednesday before the next system affects our
region Thursday through Friday. Increased winds along with possible
low level wind shear and turbulence are likely Friday. -Johnston

&&

.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&

$$

For more information from the National Weather Service visit...
http://weather.gov/reno




Area Forecast Discussion For Western SD and Northeastern WY

National Weather Service Rapid City SD

 808 PM MDT Mon Apr 1 2019

.UPDATE...
Issued at 806 PM MDT Mon Apr 1 2019

Short wave and associated showers over northeast MT have some
chance of crossing our northwest SD zones after midnight, so have
added pops for that area. Rest of forecast largely unchanged.

&&

.DISCUSSION...(This Evening Through Monday)
Issued at 235 PM MDT Mon Apr 1 2019

The latest water vapor images and RAP analysis indicated an upper
trough over the CWA in northwest flow, while one short-wave trough
was over the eastern CWA and another short-wave trough was moving
southeast across central MT. The lead trough was producing mostly
snow that has brought a few to several inches across a narrow
swath from roughly K2WX to KPHP. This wave should exit to the east
this evening with snow/rain coming to an end. Otherwise, steep
(7-7.5 C/km) midlevel lapse rates and the upstream wave will allow
for scattered snow/rain to move across most of the rest of the
CWA through early evening, with perhaps isolated thunder over
northeastern WY. This too should come to an end by 06z.

On Tuesday the flow aloft will be northwesterly and confluent while
an upper trough moves over the western CONUS. The net result should
be dry weather, but with some increasing clouds over the southwest
ahead of the next trough in the weak warm advection regime.

Tuesday night and Wednesday an upper low will move across AZ/UT and
then across the TX/OK panhandles to eastern OK by 12z Thursday. The
overall forcing for ascent looks weak over the CWA as upper
divergence, Q-vector convergence, and isentropic lift will be
minimal. Some frontogenesis is progged over the far southern CWA,
but midlevel lapse rates only look to be 5-5.5 C/km (much less than
today). Flow aloft also will remain confluent Tuesday night, with
westerly flow on Wednesday. The net result will be modest lift with
relatively minor snow/rain accumulations--highest near the
Nebraska border.

Ridging will ensue Thursday as an upper trough moves from MT to ND
during the day. Low-level temperatures should really shoot up
Thursday afternoon with above-average temperatures through the
weekend. A broad upper trough will reach MT/WY on Saturday, passing
through the CWA overnight. This may bring scattered showers and a
few thunderstorms to the area.

&&

.AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening)
Issued At 518 PM MDT Mon Apr 1 2019

Isolated convective rain showers across portions of SW SD will
wane after 00-03Z tonight. These showers and low clouds will
produce transient MVFR conditions, mainly across SW SD and central
SD. Otherwise, VFR conditions will prevail through the forecast
period.

&&

.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&

$$

Update...Johnson
DISCUSSION...Bunkers
AVIATION...Eagan