Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/18/19
Area Forecast Discussion
National Weather Service Charleston SC
847 PM EDT Tue Sep 17 2019
.SYNOPSIS...
Hurricane Humberto will continue to move away from the coast
through mid week. A cold front will advance through the area
Wednesday, followed by high pressure into early next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Quick Update to add slight chance POPs to Allendale County and
surrounding areas. Radar shows isolated thunderstorms
approaching this area. The HRRR indicates they should persist
for at least the next 2-3 hours. We may need to expand this
areal coverage further, depending on the future radar trends.
Otherwise, a cold front will move south and should make it
toward the Altamaha River near daybreak as Hurricane Humberto
well offshore continues to move farther away. Some showers are
expected to develop as moisture, instability and convergence
increase a bit. Can`t rule out some weak storms but any thunder
should mainly be confined to around the GA coast where the
greatest instability is expected. Temperatures should fall to
around 70 north and west toward the Pee Dee/Midlands with lower
to mid 70s south and east toward the coast and GA Coastal
Empire.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday: Models in good agreement that the backdoor front will
move through the area from north to south during the day. Models
show some increase in moisture associated with the front and this is
supported by cloud cover across Virginia at the present time. Some
minor instability is expected to develop mainly in the afternoon
across southeast Georgia. Threat for precipitation is low enough in
the north due to the early arrival of the front that it was left out
of the forecast. Highest rain chances will be in the south. Threat
for precipitation will end by late afternoon. Made some minor
adjustment to lower high temperatures from the Allendale/Walterboro
areas south to near Savannah. Maintained highs in the mid to upper
80s southwest of this area, but have some concern that cloud cover
may be sufficient enough to keep the high temperatures from getting
that high. Highs will mainly be in the lower 80s in the north and
along southeast South Carolina Coast. Drier air will move in behind
the front with lows Wednesday night ranging from near 60 in the
north to near 70 along the southeast Georgia Coast.
Thursday: Drier air will continue to overspread the area in the wake
of the cold front. The only exception will be along the southeast
Georgia Coast near the Altamaha River where a few very light marine
showers could brush the coast. Brisk northeast winds are expected
along the coast. High temperatures area wide will be rather mild
and this combined dew point temperatures in the 50s inland to the
lower to mid 60s at the coast will make for a rather pleasant day.
Highs should range from the upper 70s near the South Santee River to
the mid 80s across far inland portions of southeast Georgia. A few
light marine showers are possible in southeast Georgia mainly east
of I-95 Thursday night.
Friday: As surface high pressure begins to build from the Mid-
Atlantic states into the western Atlantic, surface winds will become
more onshore especially from Beaufort County south and this will
allow the threat for some light marine showers to spread further
inland especially across southeast Georgia. Highs should range from
near 80 along the coast to the mid 80s far inland where more
sunshine is expected and there is basically no threat for
precipitation.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Deep layered ridging will persist over the weekend and then
tend to break down during the first part of next week. Models
continue to show dry weather prevailing through the entire
period. High temps are expected to warm slightly above climo
during the period, however overnight temps should continue to
fall into the 60s each night away from the ocean as the
atmosphere remains quite dry.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
00Z TAFs: A cold front will move through the terminals late
tonight into Wednesday morning.
KCHS: Models indicate mainly dry conditions as the front passes.
Hence, we have VFR prevailing. Though, winds could become gusty
behind the front Wednesday afternoon.
KSAV: Models show isolated to scattered showers developing ahead
of the front. Since their is some uncertainty with the timing of
these showers and their coverage/intensity, we opted to cover
this with a PROB30 group and hint at borderline VFR/MVFR
ceilings. Models even show hints of MVFR ceilings into
Wednesday afternoon, but we`re keeping it barely VFR for now.
Additionally, gusty winds could develop behind the front
Wednesday afternoon.
Extended Aviation Outlook: VFR conditions will prevail.
&&
.MARINE...
Tonight: A cold front will move south through most, if not all,
of the waters with winds picking up from the northeast behind
it. Seas will also build as a result and Small Craft Advisories
are in effect for all waters except Charleston Harbor and the
nearshore GA waters.
Wednesday through Sunday: Northeast winds will dominate
throughout the week in the wake of the backdoor cold front that
moves through the waters on Wednesday. The combination of
increasing seas and winds will result in Small Craft Advisory
conditions for all coastal waters into Friday evening for the
nearshore waters and well into Saturday night for the offshore
Georgia waters. Looks like the best threat for Small craft
Advisory conditions to occur in Charleston Harbor will be on
Thursday. Later shifts will need to further evaluate and if
necessary issue an advisory there.
Rip Currents: Moderate Risk through Wednesday due to lingering
elevated long period swells and increasing longshore currents
due to strengthening northeast winds.
The rip current risk will remain elevated through the end of the
week as northeast winds and strong longshore currents continue.
&&
.TIDES/COASTAL FLOODING...
Low chances for minor coastal flooding around the times of high
tide through late week, especially along the South Carolina
coast.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory from 2 AM Wednesday to 8 PM EDT Friday
for AMZ352.
Small Craft Advisory until 4 AM EDT Sunday for AMZ374.
Small Craft Advisory until 8 PM EDT Friday for AMZ350.
Small Craft Advisory from 11 AM Wednesday to 8 PM EDT Friday
for AMZ354.
&&
$$
NEAR TERM...
SHORT TERM...MTE
LONG TERM...
AVIATION...MTE/RAD
MARINE...MTE/RJB
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Dodge City KS
716 PM CDT Tue Sep 17 2019
...Updated Aviation Section...
.SHORT TERM...(This afternoon through Wednesday night)
Issued at 1130 AM CDT Tue Sep 17 2019
Strong S/SW winds will impact SW KS through this afternoon, with
gusts to the 40-45 mph range. A strong shortwave was over western
Wyoming at midday, complete with morning forced convection in
southern Wyoming via the lightning detection network. This system
is dynamically impressive and will rotate in a negatively tilted
fashion into western South Dakota this evening. This will all
enhance pressure gradients through this evening, with MOS guidance
now up to 29 mph sustained for several hours. Gusts to near 45 mph
are expected through sunset, with more persistent, well above
normal temperatures in the lower to mid 90s. 12z NAM, the latest
HRRR iterations and a few other CAMs suggest isolated thunderstorm
development is possible along/west of US 83 this evening. Included
20% pops for this potential, but coverage will be sparse, and
wouldn`t be surprised if nothing develops at all. That said, a hot
well-mixed windy boundary layer will support downburst potential
from any high-based storms that develop.
Another unseasonably warm night tonight, with sunrise
temperatures in the 60s west, to lower 70s east. South winds will
remain elevated at 15-25 mph well into the night, courtesy of
another low level jet.
A break from the Kansas wind machine is expected Wednesday. The
shortwave to our north will be out of the picture, but more
importantly, a weak surface trough of low pressure will bisect
SW KS as a weak surface high pressure ridge noses into Nebraska
and NW KS. This setup will reduce the winds substantially, still
south at 15-25 mph south of the trough, but probably going light
and variable (at times NEly) near and north of the boundary. Winds
will likely be the lightest across the western/NW zones. Model
consensus places the boundary near a Wakeeney-Garden City-Liberal
line at midday. Given convergence along the boundary, long range
HRRR and 12z NAM hint at isolated thunderstorm development. Again,
coverage will be sparse, but will necessitate at least minimal
pops. Another hot afternoon in the mid 90s will both encourage
updrafts and downbursts from any high convective cloud bases.
.LONG TERM...(Thursday through Tuesday)
Issued at 210 PM CDT Tue Sep 17 2019
...Severe Thunderstorms Possible Friday...
Shower and thunderstorm activity will clearly return to SW KS
Thursday and Friday, as a western US trough energizes SW flow
aloft, interacting with a lee trough/dryline. The trough will be
centered on the Great Basin late Thursday, with 12z GFS continuing
to suggest convective initiation across the western zones Thursday
afternoon/evening. The trough will be progressive, with models
swinging the trough axis through the northern Rockies/plains by
late Friday. Friday afternoon/evening in particular displays
severe weather potential, with 12z ECMWF depicting a sharp dryline
and surface low along the CO/KS border, and backed SEly surface
flow. As always, mesoscale details will dictate hazards, their
magnitude, and location, but early indications are some supercells
are probable from portions of western Kansas through the Texas
panhandle at peak heating Friday. Impressive shear and CAPE are
apparent, and the strong tornado parameter from 12z ECMWF is eye
opening, focusing across the western zones. Jet stream dynamics
will be impressive south of the ejecting trough. Feel severe
probabilities and NBM pops will increase with time.
Both high and low temperatures will remain well above normal
Thursday and Friday, with elevated south winds and moisture
advection. Eventually, a weak cold frontal boundary will sag
southward through SW KS over the weekend, probably assisted by
thunderstorm complex outflows. 12z ECMWF depicts MCS development
on this boundary across central Kansas late Saturday, with
probable impacts for our eastern zones. NBM pops favor the eastern
zones late Saturday which is the correct trend. Frontal forcing
and convective potential is expected to move SE of SW KS by
Sunday, and with broad ridging rebounding, a dry forecast will
return by then. Temperatures by Sunday will be closer to normal
for September, with lows from 55-65 and highs from 80-85.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 712 PM CDT Tue Sep 17 2019
Fairly quiet weather will prevail through this TAF period with
widespread VFR flight category continuing. A rogue
shower/thunderstorm was in vicinity of the LBL terminal at the
onset of this TAF period, but otherwise dry weather will remain in
place. South winds will continue through the night with a fairly
strong low level jet developing after sunset leading to some
marginal LLWS conditions not far off the surface. A surface trough
axis will advance slowly east across western Kansas on Wednesday,
and this will lead to weakening wind, especially LBL and GCK which
will be closest to this trough axis (if not right in vicinity of
this trough axis). There is still some question as to how far east
this trough axis will reach by afternoon, so there are some
uncertainties in the wind forecast in the last 6-9 hours of this
TAF period.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 69 96 68 90 / 0 20 0 20
GCK 65 95 65 91 / 20 0 10 30
EHA 62 91 64 89 / 20 0 10 30
LBL 66 95 67 89 / 20 0 10 30
HYS 69 93 68 90 / 10 20 10 20
P28 70 95 69 89 / 0 10 10 10
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Umscheid
Area Forecast Discussion
National Weather Service Grand Forks ND
1041 PM CDT Tue Sep 17 2019
.UPDATE...
Issued at 947 PM CDT Tue Sep 17 2019
Adjusted PoPs to reflect recent HRRR runs that suggest weak
convection ongoing along a pre-frontal trough across central SD
will intensify as it moves into northeast SD and interacts with a
less stable environment. Recent radar and lightning trends suggest
this convection has been slowly intensifying, so the recent HRRR
runs seem reasonable. Will continue to monitor for the potential
for severe weather through the night across far southeast ND and
west central MN.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 343 PM CDT Tue Sep 17 2019
For tonight, a similar setup to yesterday is expected with a cold
front moving east across North Dakota.
Expect to see gusty southerly winds decrease this evening with
temperatures remaining mild due to increased cloud cover. Canadian
and GFS guidance both suggest the possibility of light rain
showers west of Devils Lake due to a weak 500mb shortwave.
Tonight, a broad 850mb jet out of the south will be providing
warm air advection, strongest across Minnesota. The jet will be
similar to yesterday and possibly stronger to near 60 knots in
some areas. There has been disagreement for the placement and
timing for convection, but the trend has been pushing initiation
later than midnight and further to the east than previously
expected. Fergus Falls and Park Rapids have the best chances
after midnight and before sunrise. The showers and storms will
push northward during the morning.
With the southern end of the upper-level trough lingering
throughout the day near the international border, some rain
showers may be possible in that area during the afternoon. Winds
will become westerly and very gusty at times with 30mph gusts
possible along and west of the Red River Valley. Highs will be
slightly cooler in the 70s area-wide.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 343 PM CDT Tue Sep 17 2019
With winds and cloud cover expected to subside behind the front,
temperatures will be cooler but still above normal for Wednesday
night. Lows will be in the 50s with stable air keeping the area
dry.
12Z Thu - 00Z Sat
Low level moisture returns to the Red River Valley late Thu night
into Fri. Precipitable water rises Thu night and Fri to around 1.5
inches. Models soundings show instability increases Thu night as
well as the cap. Cap dissolves by Fri afternoon. Also Cape throttles
back as mid level temps increase. Shear is stronger in the western
Dakotas Fri and shifts over the forecast area on Sat.
Sat - Tue
Long wave trough over the western US will shift to eastern North
America by the end of the period. Low amplitude long wave ridge over
the eastern Pacific shifts. The GFS becomes the faster solution
compared to the ECMWF on Sat. But by Sun the models phase back up.
Upper low off the Pacific Northwest coast will move across the
region Sat. Main frontal boundary to move through Sat and majority
of precip will shift into Canada by later Sat. European and GFS
ensembles give best precip for Fri and Sat. Heavy rain will also be
possible.
&&
.AVIATION...(For the 06Z TAFS through 06Z Wednesday night)
Issued at 1040 PM CDT Tue Sep 17 2019
VFR conditions are expected to continue overnight tonight for most
locations. The exception is KBJI where scattered showers and
thunderstorms are expected as a cold front pushes through the
region. As this occurs, MVFR, and possibly period of IFR, conditions
are likely.
The main impact for aviation in the TAF period will be the winds.
Southerly winds sustained at 10-15 knots will diminish slightly
overnight before shifting to the west and picking back up Wednesday
morning. One exception to this is KFAR which has continued to see
gusts into the 20-30 knot range well after sunset. Given that this
location saw persistent overnight gusts last night under a similar
weather regime, wind gusts into the 20-25 knot range overnight can`t
be ruled out.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...AM
SHORT TERM...Godon/Wasilewski
LONG TERM...Godon/JH/Wasilewski
AVIATION...AM
Area Forecast Discussion
National Weather Service Hastings NE
614 PM CDT Tue Sep 17 2019
...AVIATION UPDATE...
.SHORT TERM...(This evening through Wednesday Night)
Issued at 308 PM CDT Tue Sep 17 2019
The gusty south winds will continue through this afternoon, but
will gradually taper off this evening as low level mixing
decreases. Winds will then back off even more as a cold front
moves in from the northwest after midnight. There is still a
chance that a few showers or thunderstorms could develop as an
increasing LLJ intersects this front, but the latest runs of the
HRRR have been pretty unimpressive.
This front then stalls in the area tomorrow, which creates some
uncertainty on high temperatures for tomorrow. The current
forecast has a range from 80 near Ord to the low 90s in northern
Kansas, but I wouldn`t be surprised if we see an even larger
spread in temperatures across the area.
By late tomorrow afternoon, we could see a few isolated
thunderstorms develop along the front. Then later overnight we may
see more convection develop as a shortwave pushes in from the
west. An isolated strong storm is possible through the evening and
overnight, but deep layer shear is lacking and should inhibit an
organized severe threat.
.LONG TERM...(Thursday through Tuesday)
Issued at 308 PM CDT Tue Sep 17 2019
Models have begun to show more thunderstorms lingering into
Thursday morning, especially for areas east of Highway 281. After
this activity clears, I believe that we will remain mostly dry
through the rest of the daytime as we move back into southeasterly
flow at the surface and we see rising heights aloft.
A bit better chance for thunderstorms then returns late Thursday
night into Friday as a deeper trough crosses the Rockies and
slowly moves into the central Plains. Friday will likely be
another breezy day as the trough approaches. The highest PoPs then
arrive Friday night into Saturday as the base of this trough
ejects out of Colorado.
As this trough departs, we will see more seasonable and pleasant
weather Sunday and Monday. Mostly dry conditions are expected, and
highs are forecast to be in the mid 70s to low 80s.
Confidence then decreases as models diverge on the upper level
pattern early next week. The GFS and Euro are now both producing a
cutoff low over the western CONUS, but timing and location vary
considerably.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday)
Issued at 608 PM CDT Tue Sep 17 2019
SFC winds will taper off this evening a 45-50kts LLJ will setup
causing some LLWS at the TAF sites tonight. A cold front moving
through the region tomorrow will cause some challenging wind FCST.
Some models keep the winds out of the south and others bring it
out of the north. Have elected to keep a northerly wind in the
TAFS at this time, some cooler weather would be nice.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Mangels
LONG TERM...Mangels
AVIATION...Beda
Area Forecast Discussion
National Weather Service Springfield MO
638 PM CDT Tue Sep 17 2019
.SHORT TERM...(This afternoon through Wednesday)
Issued at 1231 PM CDT Tue Sep 17 2019
We are pretty much on track with temperatures this afternoon with
most locations already in the lower to mid 90s. A few patches of
cumulus were building over the area with the thicker patches
between Rolla and Ft. Wood and near Table Rock Lake. Much thicker
cumulus was developing east of our forecast area over southeast MO
and western KY/TN.
The latest HRRR has been trending even more isolated with
afternoon storm coverage. Will monitor cloud trends southwest of
Springfield for isolated storm development also, with any activity
diminishing after sunset.
There will not be much change in overall weather pattern for the
next 24 hours, so will continue with hot afternoon conditions and
isolated afternoon storms. Expect to see a slight uptick in
coverage compared to today as moisture from the northern Gulf
tropical depression shifts northward.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 255 PM CDT Tue Sep 17 2019
The upper ridge currently over the region will build further to
the east as moisture increases ahead of a deepening trough over
the western US. With added moisture from the remnants of Imelda we
could see a little more coverage in afternoon storms over our
southwest counties, and overall temperatures a few degrees lower
than Wednesday, but still above normal.
Will continue to keep the increasing precipitation chances from
Friday through the weekend as the upper trough shifts eastward
into the upper Midwest and places our region in southwest flow
aloft. Several disturbances will interact with a surface front and
moisture from the tropical storm remnants. Have some concerns
that flooding from training storms will become more likely later
in the weekend if the surface front lines up parallel to the upper
flow. Have included flooding potential in the Hazardous Weather
Outlook for late Saturday and Sunday.
A weak shortwave ridge is forecast to build back into the region
on Monday and Tuesday. However will hang on to some low precip
chances as the GFS keeps a front stalled over the region.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 636 PM CDT Tue Sep 17 2019
With an upper level ridge over the region, VFR conditions are
expected through the next 24 hours. Winds will remain light from
the south as a lee side trough gradually deepens over the eastern
Rockies.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Terry
LONG TERM...Terry
AVIATION...Titus