Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/27/18

AREA FORECAST DISCUSSION...UPDATED

National Weather Service Jackson KY

 1045 PM EST Mon Feb 26 2018

.UPDATE...
Issued at 1045 PM EST MON FEB 26 2018

A few adjustments were made to hourly temperatures and dewpoints
based on trends in observations. However, this led to no
substantial changes at this time. Under high pressure,
low temperatures will be the coldest they have been in about a
week, though they will still be nearly 5 degrees above normal.

UPDATE Issued at 805 PM EST MON FEB 26 2018

High pressure continue to build into the area at the surface and
aloft. Temperatures for a few eastern valley locations have
decoupled and were dropping off a bit quicker than the previous
forecast. Hourly temperatures in these locations have been updated
based on recent trends. In addition, a couple of the min
temperatures for normally colder locations were lowered a degree
or two. Otherwise, no changes were made at this time.

&&

.SHORT TERM...(This evening through Tuesday night)
Issued at 330 PM EST MON FEB 26 2018

19z sfc analysis shows a moderately strong area of high pressure
moving through the Ohio Valley bringing some much welcomed drying
and sunshine to the area with the morning clouds now off to the
east. Winds remain light and generally from the northeast. The
sunshine has helped lift temperatures into the mid 50s most places
with dewpoints settling into a range from the mid 20s north to
upper 30s southeast.

The models are in good agreement aloft through the short term
portion of the forecast. They all depict a weakening band of
energy pulling away from the area to the east while a broad ridge
slides overhead tonight. This ridge will hold through the day
Tuesday before starting to break down on its northern fringe over
Kentucky under the influence of minor energy waves spreading east
in increasingly southwest flow. Deep layer southwest flow will
then be the rule for Wednesday morning and beyond associated with
a digging closed off low over Southern California. Given the model
agreement on the overall pattern will favor a blended solution as
a starting point with a strong lean toward the HRRR and NAM12
for wx details in the near term.

Sensible weather will feature clear skies tonight with good
radiational cooling thanks to light winds and lower dewpoints.
Accordingly, expect a moderate to large ridge to valley
temperature difference through the night - peaking at dawn.
Additionally, am concerned with some fog forming in the river
valleys overnight - frost possible in other areas - into Tuesday
morning so have included that in the grids. Tuesday will be a
pleasant day with mostly sunny skies through the morning and into
the afternoon before high clouds start to increase from the west.
With this, temperatures will top out in the low to mid 60s along
with increasing south to southwest winds by late afternoon. The
approaching low pressure system to the west will bring our dry
period to an end into Wednesday morning as it activates increasing
moisture over the area pushing showers into eastern Kentucky by
dawn while PWS climb to over 1.0 inches again. Upper level
divergence, from the right entrance region of a jet streak to the
north of the Ohio River, passing over the area early Wednesday
morning will enhance the showers into dawn as they move in from
west to east.

Again used the CONSShort and ShortBlend as the starting point for
all the grids through Wednesday morning. Did make some significant
terrain based changes to the lows tonight and also some point
specific temp adjustments for Tuesday and Tuesday night. As for
PoPs, kept it quiet until after 00z Wednesday and then ramped them
up a bit quicker than the blend into Wednesday morning - west to
east.

.LONG TERM...(Wednesday through Monday)
Issued at 330 PM EST MON FEB 26 2018

Models in reasonable agreement with the overall pattern across the
CONUS through at least the first half of the extended. Mid/upper
level flow remains amplified and somewhat progressive through the
period. Some differences do show up from time to time but in general
they appear minor enough not to significantly effect sensible
weather. We begin the extended under the influence of southwest
flow. But energy will move out of the southwest CONUS quickly and
enter the lower Ohio Valley by Dy4 Thursday. This energy will phase
with a short wave trough dropping southeastward out of Canada
resulting in a rapidly deepening low over the Mid-West. Thereafter,
ridging builds into the Mississippi and Ohio Valley for the
remainder of the forecast. Another system does approach from the
west at the very end of the forecast window. At the surface, a
potent low pressure system will develop over the central plains and
deepen rapidly as it tracks into the mid Ohio Valley, again by Dy4,
Thursday. High pressure then builds into the region for the weekend,
shifting off to the east coast by Monday as our next weather maker
just begins to enter the picture from the west by late Monday.

Sensible weather features a wet start to the extended. A stout low
level jet will pump in higher PWAT air from the out of the Gulf of
Mexico, with more moderate to heavier showers breaking out along a
developing warm front moving in from the Tennessee valley.
Widespread precipitation continues through Thursday as the system
deepens over the Ohio Valley. NAM, ECMWF, and Canadian all lay out
between 1.5 and 2.5 inches across our southern most counties through
Thursday. The GFS is an outlier at this time, putting the axis of
heavier rainfall much further south. After coordinating with
adjacent offices have decided to issue an ESF for areas generally
south of the Hal Rogers Parkway. Southwest winds continue to look
pretty strong Thursday veering to the northwest Thursday night
before tapering off through the day Friday. Winds appear as strong
behind this system, post-frontal Thursday night, as pre-frontal
during the day Thursday. As such, will continue to mentioned the
threat of gusty winds in the HWO. Precipitation will wind down from
west to east Thursday night into Friday morning, with far
southeastern Kentucky hanging on the longest as the low levels veer
to a favorable northwest downslope flow. Dry weather returns for the
weekend under the influence of high pressure.

With over 2 weeks of above normal temperatures, seasonably cool
temperatures return by the end of the week, with plenty of sunshine
to cap off the weekend. Temperatures moderate back up a bit for the
start of the following week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 740 PM EST MON FEB 26 2018

With high pressure building into and then moving across the area
through the period, VFR with only some high clouds can be
expected from time to time. A few deeper valley locations may
experience MVFR or IFR vis between 7Z and 13Z, but this is not
expected to affect the TAF sites. Winds will be light through the
period.

&&

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

$$

UPDATE...JP
SHORT TERM...GREIF
LONG TERM...RAY
AVIATION...JP



Area Forecast Discussion

National Weather Service Marquette MI

 641 PM EST Mon Feb 26 2018

.SHORT TERM...(This evening through Tuesday)
Issued at 410 PM EST MON FEB 26 2018

WV imagery and RAP analysis indicated a mid/upper level trough into
the wrn CONUS and a broad ridge through the plains and MS valley
resulting in a mild flow of Pacific air into the region. At the
surface, sw flow prevailed through the wrn Great Lakes between low
pressure north of Lake Winnipeg and a ridge over the Ohio Valley.
Otherwise, vis loop showed an area of WAA mid/high clouds sliding
through the nrn Great lakes leaving mostly sunny skies.

Tonight, Mid-level and sfc ridging will maintain dry conditions.
Additional bands of mid/high cloiuds will move through the area.
Otherwise, southwest winds will keep low-levels well mixed so that
min temps will only drop into the mid to upper 20s.

Tuesday, expect increasing clouds as a weak shortwave trough
approaches the region. Any pcpn into the srn cwa associated with a
band of mid level fgen is expected to hold off until Tue night. Even
with the additional clouds, temps will again climb into the low to
mid 40s.

.LONG TERM...(Tuesday night through Monday)
Issued at 326 PM EST MON FEB 26 2018

Overall, quasi-zonal flow across the CONUS will break down and
become highly amplified by the end of the week as a slowly
progressive trough, ridge, trough pattern develops across the CONUS.
Through this week, the weather looks to remain fairly quiet with
mild, above average temperatures for this time of year.
Precipitation wise we should remain fairly quiet, but do have a few
chances through the middle to end of the work week for some light
wintry precipitation. Otherwise, high pressure will take over
through the end of the work week and much of the weekend, giving way
to dry weather.

Tuesday night through Wednesday: Light wintry precipitation is
possible Tuesday night across the south central and east. Forecast
soundings do not show much depth to the moisture and/or temperatures
cold enough to support snow. Therefore, precipitation will likely
fall as freezing drizzle if the cloud depth is deep enough to
support droplet growth, which could allow for impacts to the morning
commute on Wednesday. High pressure will then quickly settle into
the region during the day on Wednesday and allow cloud cover to
gradually diminish.

Thursday through Friday: A strengthening surface low will lift
northwards towards the Ohio River Valley Thursday as a potent
shortwave ejects out of the Plains. Model trends have consistently
trended further south with the heavier precipitation associated with
this system, which make sense based on the track and orientation of
the mid-level trough, along with the drier air being advected
southward on the northwest side of the system. Therefore, the only
noticeable change we should see is a bit colder temperatures late
Thursday through Friday, with a few lingering chances for light
wintry precipitation off of Lake Michigan. Right now 850mb
temperatures look marginal, so it may even be a stretch to get any
ice growth within the lake effect clouds.

Upcoming weekend: We will be sandwiched in between systems over the
west and east coast this weekend. With upper-level ridging
dominating the upper-level pattern, expect a dry weekend as high
pressure will linger across the region. Towards the very end of the
weekend into early next week, the western most trough will gradually
move eastward towards the Great Lakes region and may bring the next
best chance for widespread precipitation. However, given the quasi-
blocking pattern progged to be in place across the CONUS, wouldn`t
be surprised if this system is delayed even further. Regardless,
it`s far early to think about any details as the track and speed of
this system will highly dictate any impacts.
&&

.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 641 PM EST MON FEB 26 2018

VFR conditions are expected through the forecast period. LLWS is
expected at all sites tonight as SW winds increase above the low
level inversion.
&&

.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 410 PM EST MON FEB 26 2018

Tonight through the end of the week, winds are expected to remain
below 25 knots.
&&

.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&

$$

SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...Titus
MARINE...JLB