Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/23/18

Area Forecast Discussion

National Weather Service Cheyenne WY

 955 PM MDT Sun Apr 22 2018

.UPDATE...
Issued at 952 PM MDT Sun Apr 22 2018

We are sending out a quick update to add a little fog to the North
Platte River Valley. Otherwise, rest of the forecast looks to be
in good shape.
&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 200 PM MDT Sun Apr 22 2018

Next system set to move into the area Monday. Forecast challenges
deal with overnight fog tonight and thunderstorm locations
Monday/Monday evening.

Currently...CWFA looking good this afternoon after some fairly
widespread morning fog. Looks like all locations have finally
burned off with sunny skies just about everywhere. Still have some
low stratocu over the eastern Panhandle, but that should be gone
in the next hour or so. Next cold front moving into eastern
Oregon/central Idaho.

For tonight, still believe we have a chance at some fog
development as soils are still wet and we are going to be under
clear skies/light winds. HRRR hinting at low conditions from
Kimball County Nebraska west to Cheyenne this evening after 06Z,
persisting through sunrise. Low level winds from forecast
soundings continue to be southeast in this area, so did add areas
of fog back into the forecast for tonight. HRRR also showing some
low conditions up by Lusk tonight, so added patchy fog up there as
well.

Increasing clouds through the day as upper shortwave and
associated surface cold front move into Carbon and Converse
Counties after 18Z. Looks like the front passes through the
Cheyenne area after 00Z and through the southern Panhandle by 03Z
Tuesday. Steepening mid level lapse rates as the colder mid level
air moves into the area on the order of 8C/KM with Lifted Indices
-3C just ahead of the front. Did keep isolated thunderstorms going
 in the forecast across southeast WYoming into the Nebraska
 Panhandle Monday afternoon.

Rain to turn over to snow behind the front Monday night into
Tuesday as 700mb temperatures fall from +4C monday 18Z to -4C
Monday night. Fairly fast moving system, so do not expect headline
level accumulations of snow, but some travel impacts are possible
Monday evening into Tuesday.

.LONG TERM...(Wednesday through Sunday)
Issued at 200 PM MDT Sun Apr 22 2018

Wednesday...Northwest flow aloft and a transitory low amplitude
shortwave ridge aloft will prevail, producing a dry day. Relatively
mild temperatures with maximums in the 60s with 700 mb temperatures
near 4 Celsius.

Thursday...A bit cooler in the wake of a passing dry cold front
associated with a shortwave trough aloft passing across the Northern
Plains states. Continued dry with limited low and mid level moisture.

Friday...Warmer again as a ridge aloft builds across the Rockies.

Saturday...Next shortwave trough aloft moves into Idaho and Utah
with increasing southwest flow aloft over our counties. Looks like
enough low and mid level moisture overhead to spawn isolated
afternoon showers. Continued mild with maximum temperatures in the
60s to lower 70s with 700 mb temperatures near 8 Celsius.

Sunday...Slightly cooler with isolated showers as a shortwave trough
aloft moves overhead.

&&

.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 540 PM MDT Sun Apr 22 2018

Latest water vapor loop was showing an amplified upper level trof
moving through the Pacific northwest. This feature will continue
to drive east into Wyoming during the next 24 hours. As a result,
we will see wind speeds increase a bit Monday morning as the
gradient begins to tighten up ahead of the cold front. This front
will begin to drop into the KRWL, KLAR, KCYS, KBFF and KCDR TAF
sites after 21z. Until then mostly VFR conditions are expected.
However, we may see some patchy fog around KBFF and KCYS towards
daybreak.


&&

.FIRE WEATHER...
Issued at 200 PM MDT Sun Apr 22 2018

Wetting rains and accumulating mountain snow returns to southeast
Wyoming and Nebraska Monday as a cold front moves into the area
from northwest to southeast. Just about every location should see
wetting rains Monday into Tuesday. So fire weather concerns are
going to be minor through the upcoming week. Another front
possible Thursday, but this one does not look as strong as the
front Monday/Tuesday. Warmer temperatures through the week should
help to kick off greenup across the area.

&&

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

$$

UPDATE...REC
SHORT TERM...GCC
LONG TERM...RUBIN
AVIATION...REC
FIRE WEATHER...GCC




Area Forecast Discussion

National Weather Service Green Bay WI

 553 PM CDT Sun Apr 22 2018

Updated aviation portion for 00Z TAF issuance

.SHORT TERM...Tonight and Monday
Issued at 231 PM CDT Sun Apr 22 2018

The latest RAP analysis and satellite/radar imagery show a large
area of high pressure stretching from the east coast to the
northern Mississippi Valley early this afternoon. Split flow
continues to dominate the upper air pattern across the central
NOAM, with a storm system over the south-central part of the
country and another over central Canada. Between these systems,
skies remain mostly clear except for some thin, wispy cirrus
shifting into central WI on the far northern edge of the system
further south. With systems continuing to split north and south of
the state, the main forecast concerns revolve around temps and
humidities.

Quiet weather will continue across the region through Monday
afternoon thanks to high pressure. Some cirrus from the storm
system to the south will likely get caught up in the westerlies
and invade the region later tonight into Monday. Although some
moistening will occur, very dry air will remain below 500mb, so
any thin cirrus should not have much impact on temps. Still no
sign of fog during the overnight hours, despite all of the melting
take place. Will continue to keep fog out of the forecast.
Temperatures will continue their warming trend, with lows in the
20s and 30s tonight, and in the upper 50s to mid 60s on Monday.
Readings will be cooler near Lake Michigan due to light onshore
flow. Dropped humidities across far northern WI again tomorrow
afternoon based on trends over the past few days, and little
change to the airmass in place.

.LONG TERM...Monday Night Through Sunday
Issued at 231 PM CDT Sun Apr 22 2018

The highlights from the long term are the warmer temperatures
continuing to chip away at the snowpack, a shortwave trough/cold
front moving into the area on Tuesday afternoon, and the passing
of another shortwave trough/cold front for Thursday into Friday.

A split flow pattern remains over the area for the start of the
long term with zonal flow to the north of Wisconsin and a low
pressure system sitting over the Tennessee Valley. This flow will
change heading into Tuesday morning with the approaching shortwave
trough/cold front. Model guidance is in agreement with the timing
for the cold front passing over Wisconsin Tuesday afternoon. This
will keep high temperatures for Tuesday close to and slightly
above normal ahead of the frontal passage. The uncertainty of this
system remains with how much post-frontal precipitation is
generated. Compared to yesterday, the GFS has backed off with
precipitation and the Canadian added some in for Tuesday evening.
Kept slight chance pops in for Tuesday afternoon over central and
far northeast Wisconsin.

Conditions for Wednesday will remain dry and slightly cooler with
temperatures closer normal before the next shortwave trough/cold
front arrives. The models are still not in agreement with timing
of this shortwave trough/cold front. Due to the disagreement, a
blend of the GFS and ECMWF was favored for the timing of the
frontal passage. In doing so, the best chance for precipitation
would be during Thursday afternoon and Thursday night behind the
cold front. With the cooler air filling in behind the front, it
is possible for any rain to mix with or change completely over to
snow Thursday night into Friday morning. At this time, any
accumulations look quite minor.
&&

.AVIATION...for 00Z TAF Issuance
Issued at 553 PM CDT Sun Apr 22 2018

VFR conditions with light winds will prevail through the TAF
period. The very dry airmass in place continues to prevent fog
development during the overnight hours.
&&

.HYDROLOGY...
Issued at 231 PM CDT Sun Apr 22 2018

Warming temperatures will continue to produce melting of the
current snowpack over northeast WI. This will lead to additional
runoff and the steady rise of area rivers and streams. Several
rivers are expected to surpass bankfull and more are likely over
the next couple of days. The Oconto River near Oconto is forecast
to reach flood stage Monday morning and the Wolf River is
projected to reach flood stage at Shiocton Monday afternoon.
People living near rivers and streams should keep a close eye on
the anticipated river rises and keep up to date on the latest
river forecasts.
&&

.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM.....MPC
LONG TERM......Hykin
AVIATION.......Kurimski
HYDROLOGY......Hykin



Area Forecast Discussion

National Weather Service Louisville KY

 935 PM EDT Sun Apr 22 2018

...Forecast Update...

.Forecast Update...
Issued at 930 PM EDT Sun Apr 22 2018

Current radar shows band on light showers remaining across south
central Kentucky. Earlier band of showers that had lifted into north
central KY and southern IN has mostly dried out in the last 60
minutes. This idea was well represented in the HRRR runs. Looking
south, the next widespread area of rain showers will begin to
overspread the area south to north overnight through Monday morning.

Minor adjustments were made to the near term precipitation chances
using the latest hi-res guidance. Otherwise, the forecast is on
track.

&&

.Short Term...(This evening through Monday night)
Issued at 314 PM EDT Sun Apr 22 2018

The first round of rain is slowly moving into parts of south central
Kentucky this afternoon ahead of a fairly large upper level low
(ULL) currently in Arkansas. Forecast models suggest this band of
precipitation will weaken and slow down as it moves northward across
central Kentucky late this afternoon. Another surge of moisture and
rain will quickly move in behind the first round this evening as the
ULL moves steadily toward Kentucky.

Forcing and lift will be supportive of widespread showers with this
second round of rain tonight, and a +50kt LLJ will aid in
transporting moisture northward. It may not be until after midnight
that parts of northern Kentucky and southern Indiana see any rain,
and the trend as of late has been to slow things down. Plan on
having PoPs start for northeastern areas of the CWA just before
sunrise Monday morning.

Drier air wrapping into the ULL will allow for some breaks in the
rain starting Monday morning across south central Kentucky, and
eventually spreading northward Monday afternoon. Models vary quite a
bit on how much of a break we will see, and if there will be any
clearing. With the ULL closing in on southwestern portions of the
CWA Monday afternoon, colder air aloft will allow for some
steepening of lapse rates. In areas that see clearing and a bit of
sunshine, instability could develop. The NAM/GFS show anywhere from
200-300J/KG to 1500J/KG tomorrow afternoon near the BWG area, though
the higher amounts seem a bit overdone. Deep layer shear is nothing
to brag about (0-6km ~25kts), so the threat for severe weather
should remain very low should any instability be realized. With cool
temperatures aloft, we could see some small hail fall in some of the
stronger thunderstorms that develop. Should storms form along
mesoscale boundaries, isolated cold air funnels can`t be ruled out
as well.

Showers will linger through tomorrow night as the ULL moves into
central Kentucky. Best chances for rain will be across the Kentucky
Bluegrass where the best forcing and lift are projected ahead of the
ULL. Temperatures will remain mild, generally in the 50s.

.Long Term...(Tuesday through Sunday)
Issued at 326 PM EDT Sun Apr 22 2018

The upper level low will continue its slow journey to the northeast
on Tuesday. The NAM/GFS indicate some clearing may occur across
parts of the Kentucky Bluegrass and Lake Cumberland region Tuesday
afternoon, resulting in some instability developing. Similar to
Monday, not expecting any severe weather due to weak wind shear, but
could see some small hail in stronger storms due to cold
temperatures aloft.

What`s left of the upper level low will get picked up and absorbed
into an approaching trough on Wednesday. We should see a brief
period of dry weather before another approaching trough/surface cold
front moves in from the northwest sometime Thursday night or Friday.
The model timing differences continue, so will keep PoPs low until
there`s better agreement. By the time we get into the weekend,
surface high pressure will begin settling over the Southeast. A
rather large upper level ridge could establish itself over the
eastern third of the country by the end of the weekend, and could
lead to a period of prolonged warm temperatures and mostly dry
conditions.

&&

.Aviation...(00Z TAF Issuance)
Issued at 710 PM EDT Sun Apr 22 2018

Large upper level low pressure system near MEM will slowly move
eastward toward the northern TN and southern Ohio Valleys during the
TAF period.  We will see the lowering of ceilings through the period
with the best chances of rainfall this evening at KBWG and KHNB.
Rain will spread into the KSDF terminal late tonight and into the
KLEX terminal toward morning.  Ceilings will start off VFR but are
expected to drop into the MVFR category overnight.  Winds will
remain out of the east/southeast and will remain steady overnight.
Still could see some weak LLWS conditions at KBWG/KHNB/KSDF
overnight between 23/04-10Z.


&&

.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&

$$

Update...ZT
Short Term...DM
Long Term....DM
Aviation.....MJ




Area Forecast Discussion

National Weather Service Tucson AZ

 325 PM MST Sun Apr 22 2018

.SYNOPSIS...Expect dry conditions across much of the area and
unseasonably warm daytime temperatures this week. The exceptions are
a few light showers possible southeast of Tucson this afternoon, and
a few afternoon thunderstorms near some eastern mountains the
second half of the week.

&&

.DISCUSSION...As expected, the weak low we`ve been looking at
from the eastern Pacific has opened up as it moves through
northern Mexico and southern Arizona. Lower levels have remained
dry with surface dew points in the teens to 20s and most of the
moisture at 500mb on the 12Z sounding. That same sounding also
showed an increasing trend between 700-500mb though, and current
satellite estimated precipitable water is up to around .65 inches
(from 1/3 of an inch yesterday afternoon and 1/2 inch this
morning). The ACCAS around the area just after sunrise told a
story that has evolved into plenty of virga today, and even some
sprinkles to light showers. Current development is noted southeast
of Tucson in Cochise county where we had good solar insolation.
HRRR trends continue to suggest some enhancement near the
Chiricahua mountains over the next few hours. Still wouldn`t be
surprised by a lightning strike or two there with a small bullseye
of 250 MUCAPE near there.

Otherwise, steady as she goes with the warming trend into early
this week with dirty and long period ridging. Another low has
split from the northeast Pacific and into a position well off the
coast of Baja. As it comes through, this will make Wednesday and
Wednesday evening a lot like today. After Wednesday, we`ll
continue to see enough mid level moisture with weak disturbances
embedded in the flow to bring a few thunderstorms to the eastern
mountains later in the week. Friday looks particularly interesting
with increasing GFS/ECMWF H7 theta-e trends from central through
northwest Mexico.

Model divergence at that point with a more progressive GFS
shunting storm chances east of our area next weekend, while the
ECMWF is less aggressive in reconsolidating the flow south and
southeast of the Gulf of Alaska and is thus slower.

&&

.AVIATION...Valid through 24/00Z.
Isolated -SHRA possible near the New Mexico state line through
23/03Z. Otherwise, FEW-BKN clouds 10k-15k ft AGL with SCT clouds
above 20k ft AGL for the rest of the afternoon before gradually
decreasing in coverage through late evening. Skies will be mostly
SKC by Monday morning. SFC winds will remain light and terrain
driven at generally less than 10 kts for the forecast period.
Aviation discussion not updated for TAF amendments.

&&

.FIRE WEATHER...A few light showers will be possible across
eastern zones this evening, with the main focus being in southern
Cochise County. Dry conditions will return for Monday and Tuesday
before a slight chance of thunderstorms develops across the eastern
mountains during the afternoon hours Wednesday through Saturday. Any
lightning would enhance fire initiation concerns and gusty outflows
may also occur. Above-average temperatures will continue for this
week alongside generally light and terrain driven winds, with a few
afternoon gusts due to daytime heating.

&&

.TWC WATCHES/WARNINGS/ADVISORIES...None.

&&

$$

Meyer/Pegram

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