Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/08/19
Area Forecast Discussion
National Weather Service Bismarck ND
1004 PM CDT Fri Jun 7 2019
.UPDATE...
Issued at 1000 PM CDT Fri Jun 7 2019
Main change for this update was decrease the severe thunderstorm
threat north and west of the current watch area. Near term models
continue to suggest convection currently across northern South
Dakota will rise north and east tonight. The latest iteration of
the HRRR still has a few updraft helicity tracks moving into
central North Dakota suggesting there is still some severe weather
potential within the multicellular clusters.
UPDATE Issued at 659 PM CDT Fri Jun 7 2019
So far the convection over central ND is having a hard time
getting started. The northern portion of the line is looking more
favorable for organized convection. CAMS are still indicating
convection here, but with limited shear and as we pass peak
heating, the threat for severe weather may be limited to the
Devils Lake Basin and north and east.
For the southwest and south central, we are still monitoring the
potential for severe weather later this evening. This has also
trended later, but the threat remains. Will continue to monitor.
Made just some minor changes at this time to pops and sky cover.
We did let the wind advisory expire.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 341 PM CDT Fri Jun 7 2019
This afternoon, an amplified midlevel trough was moving over the
northern Rockies with an associated surface low over southern
Saskatchewan/Manitoba. At the surface a relative cold
front/surface trough axis was placed through central North
Dakota. Ahead of the frontal boundary, ample daytime heating and
surface dew points around 60 F have lead to a conditionally
unstable warm sector. Given continued destabilization this
afternoon, convective initiation is expected along the
boundary...particularly favoring the nose of a 850mb thermal
ridge from near Towner/Cavalier counties south/southwest into
Burleigh/Kidder counties. Though midlevel winds are marginal with
effective bulk shear values around 25-30 kts, ample MLCAPE values
of 2000-3000 J/kg will be enough for isolated severe hail/wind
threats along this front.
Also this afternoon, convection has been developing off higher
terrain in eastern Montana/Wyoming. This is forecast to make its
way into southwest North Dakota by 00Z-02Z along the western side
of the frontal zone. Deep layer shear values of 50+ kts and
largely parallel to the frontal zone will favor storm modes of
supercells initially and then a transition to upscale cold-pool
driven growth. With much of the storm-scale and gust front
interactions likely occurring just upstream or into southwest
North Dakota, depicting a likely storm mode has been a challenge
and will possibly not be revealed until its occurrence. If there
are still forms of discrete supercells or even clusters, large
hail and locally damaging wind gusts will be the main threats. But
with ample opportunity for storm interactions with deep shear
vectors oriented along the frontal boundary a transition to mostly
a severe wind threat is likely as this convective activity
marches through southwest into south-central North Dakota. On the
high end of the spectrum of possibilities, if a narrow corridor of
more northeasterly low level flow develops, enhancement of gust
front convergence may be possible thus developing a more
widespread severe wind threat (as highlighted by the Enhanced
risk in the SPC Day 1 outlook).
Through the day Saturday, the surface cold front slowly advances
eastward with lingering instability the basis for scattered
showers and thunderstorms. With the front advancing into eastern
North Dakota by the afternoon hours, severe weather is not
expected in the western and central post-frontal regime. Strong
cold air advection will spread across the state, leading to high
temperatures in the low 60s west to mid 70s in the James River
Valley.
.LONG TERM...(Saturday night through Friday)
Issued at 341 PM CDT Fri Jun 7 2019
The upper level trough swings through the Northern Plains Saturday
night bringing and end to the precipitation. A northwest flow
pattern then sets up Sunday through mid-week, with periodic shower
and thunderstorm chances. Temperatures will remain mainly in the mid
60s through mid 70s for highs and 40s to lower 50s for lows. We then
see a possible warming trend as we approach the end of the work
week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 659 PM CDT Fri Jun 7 2019
VFR conditions to begin the TAF period. Latest short term models
continue to show thunderstorm development trying to get going over
central ND, from east of Bismarck into the Devils lake Basin.
Later this evening, the potential for another round of convection
is expected to spread southwest to northeast across the forecast
area. Here we utilized a blend of guidance for our best guess for
timing. The timing has also slowed from earlier today. We did
include a bit higher of a wind gust potential for KDIK and KBIS
with the convection as these sites appear to be favored for the
potential for stronger winds, over remaining sites. Expect
additional updates for timing as we go through the
afternoon/evening.
All TAF sites will have the potential for MVFR to IFR cigs/vsbys in
thunderstorm activity with erratic thunderstorms winds. Northwest
flow eventually sets up across the area late tonight through
Saturday morning. MVFR ceilings are also possible Saturday behind
the cold front.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...CK
SHORT TERM...AE
LONG TERM...TWH
AVIATION...TWH
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1114 PM EDT Fri Jun 7 2019
.UPDATE...
Issued at 1114 PM EDT FRI JUN 7 2019
Showers have continued to diminish throughout the evening, with
the exception of the area of storms just south of our CWA border.
These have finally began propagating northward into our southern
counties, but they seem to be much weaker and more progressive. A
few other pop up showers are starting to show up across the SW CWA
as well. The latest HRRR has a good handle on the current
conditions, so tried to trend pops over the next few hours
towards it. This keeps likely pops in the SW CWA through about 6Z,
then tapers off to chance for the remainder of the night.
Also with the lack of rain that was originally forecast, it is
possible that the wet surface cooling could lead to fog
development. Kept coverage patchy, but expanded the fog potential
across more of the CWA to better handle this potential. Finally
loaded in the latest observations to make sure the near term
grids were on track with the current conditions. However, it was
noted that the observations have not come in for the last few
hours, so this something that will need to be addressed. All
updates have been published and sent to NDFD/web.
UPDATE Issued at 756 PM EDT FRI JUN 7 2019
Thankfully, showers have really dwindled over the last couple of
hours, with most of the CWA now seeing drier conditions. A complex
of storms remains nearly stationary just south of our CWA border
in NE Tennessee, so as time goes on it seems as though the threat
of this complex moving into our CWA is also beginning to dwindle,
with the exception of a few light showers. Reworked the pop and
weather grids through the evening and into the overnight based on
the current radar trends, as well as the latest CAM data. In
addition, made sure the near term forecasts for temps, dew points
and winds were on track with the current observations. All updates
have been published and sent to NDFD/web.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 445 PM EDT FRI JUN 7 2019
20z sfc analysis shows a broad area of low pressure south of
Kentucky with a developing warm front pushing north into eastern
parts of the state. On satellite, the colder cloud tops are found
over the southwest parts of the JKL CWA. This is associated with
a seemingly MCV spinning near our border with Tennessee. This
area is also responsible for an swath of showers and building
thunderstorms pivoting into the Bluegrass State this afternoon.
This rain could exacerbate the flood potential - especially in
western parts of the Cumberland Valley. The rain and persistent
cloud cover had kept temperatures from climbing too far into the
lower 70s for most places across the area this afternoon with
dewpoints similar. Winds through the day have mainly been from
the east to northeast at 5 to 10 mph. Some breaks in the clouds
are now working into southeast Kentucky and this could help to
build the instability leading to renewed convection and additional
heavy rains into the evening.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict a closed upper low
drifting east into the Tennessee Valley and only slowly filling
through Saturday night. Plenty of energy will circle this low
during this time keeping the upper levels active through the
period. Given this agreement have favored the NBM as the starting
point for the grids with current radar trends and the CAMs leaned
upon in the near term for PoP and QPF details. The specifics from
the NAM12 were also catered to for Saturday and Saturday night.
Sensible weather will feature a continued threat of heavy rainfall
from redeveloping showers and thunderstorms. High precipitable
water through the weekend will keep the threat around through the
entire short term portion of the forecast. Do expect the rains to
have a diurnal cycle to them favoring the afternoons and evenings,
but tonight`s threat could linger past midnight given the
maturity of the low level circulation in place with the MCV just
to our southwest. Look for areas of fog tonight when it is not
raining with additional showers and storms developing later in the
day on Saturday. Similarly, the convection should die down
Saturday night, but still be enough of a threat to maintain the
flash flood watch through the entire period.
Used the NBM guidance to start off the grids with some adjustments
to hourly temperatures at max heating and also late at night per
climatology. Did also make significant changes - mainly higher -
to PoPs and QPF to better account for near term radar trends and
the consensus of the CAMs.
.LONG TERM...(Sunday through Friday)
Issued at 510 PM EDT FRI JUN 7 2019
The models are in fairly decent agreement aloft through the
extended portion of the forecast - especially considering that it
should be a rather active pattern. They all depict the closed low
detailed above being absorbed by a fairly vigorous trough cutting
through the Central Plains Sunday night into Monday morning. This
brings additional height falls to Kentucky to start the week,
though the best energy will stay further north with the core of
the trough moving into the Great Lakes that night. Through this
trough`s passage the ECMWF is a notch stronger than the GFS and
was favored. In the wake of the initial trough, heights will
briefly rebound mid week before the next broad trough descends
into the Plains, though this time the GFS is a bit better
developed than the ECMWF. This trough continues to deepen as it
approaches eastern Kentucky with the ECMWF overtaking the GFS by
pouring its energy deeper into the region before swinging itself
through the Ohio Valley and across Kentucky on Thursday. Slowly,
heights will rebound for the area on Friday with the system
departing to our northeast - though the GFS lingers it a bit
longer than the ECMWF. Given the fair agreement for this situation
have favored the blended solution with little need for large scale
adjustments.
Sensible weather will feature a wet end to the weekend and start
to the new work week as the slow moving upper low pushes across
the area. This prolonged rain event (and threat for additional
flash flooding) ends as a cold front pushing through on Monday
with drier air moving in - even clearing the sky from west to
east that evening. Accordingly, the seasonably cool weather
continues - but without the miserable high humidity. The dry
spell of weather does not last long, though, as a developing area
of low pressure to the south brings the threat of showers and
thunderstorms back into the area by Wednesday afternoon. A passing
cold front will renew our cool weather for Thursday along with
additional chances for convection. Friday should be a dry and cool
day in the wake of the late week front as high pressure parks
over the area.
Did adjust the NBM starting point temperatures a bit at night
later in the week as the dewpoint depressions increase allowing
for likely ridge to valley differences. As for PoPs, made less
changes in the extended than the short term given the greater
uncertainty and room for larger changes as the models come into
better focus.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 808 PM EDT FRI JUN 7 2019
Latest radar trends show showers continuing to dwindle this
evening, with this trend expected to persist into the overnight.
While a few showers can`t be ruled out, widespread activity is not
likely, therefore only included VCSH. With ample moisture in
place, it is likely that fog will develop as we cool down
overnight (outside of any ongoing rainfall). While the exact
impacts and timing of fog are still in low confidence until it
develops, still expect times of IFR or below throughout much of
the night. Fog will quickly lift Sat morning, giving way to MVFR
clouds and another day of rain/thunderstorm chances. Clouds are
forecast to lift to VFR by the afternoon, but this will also be
the best time frame for convection. Went predominate -SHRA and
VCTS after 18Z to account for this. Winds will remain light and
variable through the evening and overnight, but by tomorrow
expect prevailing easterly winds, gusting to between 15 and 20 kts
in the afternoon as well.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through Sunday evening for KYZ044-050>052-
058>060-068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JMW
SHORT TERM...GREIF
LONG TERM...GREIF
AVIATION...JMW
Area Forecast Discussion
National Weather Service Memphis TN
1017 PM CDT Fri Jun 7 2019
.UPDATE...
Rain continues to fall across the region, most substantially this
hour across North Mississippi. The latest HRRR guidance suggests
much of this will come to an end over the next couple of hours.
However, with the upper low situated over the region, believe
showers will be possible areawide throughout the night. Did not
completely remove POPs tonight for this reason, but did reduce
them, especially across western areas. The Flash Flood Watch will
end across the western areas at midnight, but will continue in
the eastern counties through Saturday afternoon. With the upper
low slow to move out of the area by the afternoon hours, still
feel there`s a chance of POPs across eastern areas on Saturday.
The rest of the forecast is on track at this time, with no further
updates warranted.
ZDM
&&
.PREV DISCUSSION... /issued 641 PM CDT Fri Jun 7 2019/
UPDATE...Aviation Discussion.
PREV DISCUSSION... /issued 253 PM CDT Fri Jun 7 2019/
Currently upper level low and weak surface low were rotating
close to the Memphis metro...with moderate to heavy showers again
not moving very fast across portions of eastern Arkansas and
southwest Tennessee. Farther east ahead the system activity has
been more transient...and in locations that are gladly accepting
the rainfall. A flash flood watch has been issued to capture the
training of cells. Current temperatures ranged from the low 70s to
the low 80s. Winds were either calm or light and variable.
For tonight and tomorrow...models showing a slower trek of the
current upper level low this period with it becoming stalled in
the Tennessee River Valley by early tomorrow. CAM`s show today`s
activity once again waning quickly around sunset...but can`t rule
out redevelopment somewhere in the CWA after midnight that could
cause flooding. Later tomorrow it appears most of the heaviest
activity and coverage will be across the eastern half of the CWA.
Overall an additional 2-4 inches of rainfall is possible across
portions of the flash flood watch area. Lows tonight will drop to
near 70F with highs Saturday in the upper 70s to mid 80s.
Sunday and Monday...a stronger west northwest flow aloft of
30-40kts will slowly invade the region...though models are
showing the eastern counties still under deep enough moisture from
the upper low for significant cloud cover and scattered
convection coverage on Sunday. Elsewhere convection will become
more isolated with more sun. By Monday a fast approaching
shortwave will drop into the mid Mississippi Valley. This feature
will be accompanied by a pronounced cold front that will bring a
more April like change to the region. A few showers or storms may
form along and behind the front coupled with breezy north
winds...but it will be well worth the incoming changes with the
new airmass. Highs both days will be in the low to mid 80s with
lows Monday night falling into the low 60s.
Tuesday through Thursday...except for a few stray showers from a
passing disturbance late Wednesday in the north the period will
be mostly dry. Temperature highs will fall to around ten degrees
below normal...thats highs in the mid 70s to low 80s. More
importantly models agree on dewpoints falling into the 50s area
wide. Heat indices in the 90`s will be forgotten as AC`s can be
turn off and windows cracked open...especially at night as lows
fall to the mid and upper 50s. This cooler and drier trend may
continue into early next weekend as an upper trough remains
fixed over the Great Lakes and Ohio Valley.
JAB
&&
.AVIATION...
00Z TAF cycle
Showers and thunderstorms should continue to diminish in both
coverage and intensity over the next several hours. Additional
showers may develop tomorrow morning, though coverage is
questionable. Lows clouds should remain over much of the region
for much of the forecast period. Some patchy areas of fog may
develop overnight mainly over eastern sections of the forecast
area. Winds, generally northerly may be through the forecast
period, especially near showers/thunderstorms.
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...Flash Flood Watch until midnight CDT tonight for Clay-Craighead-
Crittenden-Cross-Greene-Lee AR-Mississippi-Poinsett-St.
Francis.
MO...Flash Flood Watch until midnight CDT tonight for Dunklin-
Pemiscot.
MS...Flash Flood Watch until midnight CDT tonight for DeSoto-Tate-
Tunica.
Flash Flood Watch through Saturday evening for Alcorn-Benton MS-
Chickasaw-Itawamba-Lafayette-Lee MS-Marshall-Monroe-
Pontotoc-Prentiss-Tippah-Tishomingo-Union.
TN...Flash Flood Watch until midnight CDT tonight for Dyer-Lake-
Lauderdale-Obion-Shelby-Tipton.
Flash Flood Watch through Saturday evening for Benton TN-Carroll-
Chester-Crockett-Decatur-Fayette-Gibson-Hardeman-Hardin-
Haywood-Henderson-Henry-Madison-McNairy-Weakley.
&&
$$