Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/11/17
Area Forecast Discussion
National Weather Service Gaylord MI
1145 PM EDT Sat Jun 10 2017
.UPDATE...
Issued at 1025 PM EDT Sat Jun 10 2017
Tight low level pressure gradient over the Northern Great Lakes
region continues to result in gusty S/SW winds across our entire
CWA late this evening. Winds are beginning to slowly diminish
thanks to loss of diurnal component to low level mixing. This
diminishing trend will continue as we head into the overnight
hours as the upstream weak front reaches our CWA. Narrow line of
convection continues to fire along this boundary aligned with a
narrow axis of instability and 850 mb theta E ridging. Latest NAM
does not appear to be handling this convection well...while the
latest RAP and HRRR have both caught on to this activity. RAP
carries some weakening convection into our CWA late tonight...
while the HRRR shows this convection coming to an end before
reaching our CWA overnight. Will adjust timing of convection into
our CWA overnight based on latest radar and model trends...and
will diminish POPs given the HRRR tendency to kill convection
before it reaches our area.
&&
.NEAR TERM...(Tonight through Sunday)
Issued at 337 PM EDT Sat Jun 10 2017
...Stickier with increasing shower/t-storm chances...
High impact weather potential...thunderstorm chances tonight,
especially late, and again midday thru Sunday afternoon. Marginal
svr threat.
Unseasonably deep (985mb) surface low is in far western Ontario, ne
of Winnipeg. Tight pressure gradient in the warm sector is driving
warmer air into the region on gusty s to sw winds. Temps are pushing
up to 90f in some areas. Some cirrus overhead, especially in eastern
upper. But the sky is almost entirely largely devoid of cu, so
needless to say there are no showers out there (except near
Whitefish Bay). Precip trends are the primary concern.
Ongoing headlines (wind/fire wx/beach hazards) will remain up thru
early evening as planned.
Tonight...surface low will move quickly ene and deepen a bit
further, crossing southern James Bay on the way of northern Quebec.
Associated cold front will cross western/northern Superior, but
remain upstream of this forecast area. Low level jet remains intact
for the 1st half of the night, before weakening/veering occur after
06z. However, the west is where the instability axis is found, and
as that folds into the region overnight, precip chances will be
increasing. Pretty strong signals from multiple RAP runs that
elevated convection will develop in parts of northern lower MI
shortly after midnight. Activity is most likely to initiate near
Beaver Isl, expanding/developing south with time. Will be boosting
pops considerably tonight, especially in northern lower MI after
05z. Will refrain from taking things into likely territory just yet.
Though an instability plume will fold in, its not terribly
impressive (perhaps reaching 1k j/kg of mucape). Broader shear
environment will become less impressive as the low level jet weakens
(0-6km bulk shear 30-40kt). And convection will clearly be elevated.
Need to monitor if something very well-organized can take a run at
us from the wnw, but otherwise deep convection may approach, but
likely not reach, svr levels.
A warm night, with sw winds for most of it and surface dew points on
the rise. Min temps near 60f in much of eastern upper, in the 60s in
northern lower.
Sunday...any leftover convection should quickly decay in the
morning. Associated cloud cover will linger a lot longer though,
with nocturnal activity contributing to moistening the airmass thru
a deep layer. Cold front lays out just to our north, while pressure
falls occur in the upper MS Valley, resulting in a developing warm
front poking into nw lower MI. This presages another push of rich
850mb theta-e air into the region. And as a result, pops will be on
the increase again, perhaps as soon as midday. Those pops will
increase further and expand northward as the afternoon proceeds.
We look to have enough cloud cover to limit instability to some
degree. Some pockets of better heating are likely, and a localized
svr threat may emerge as a result (ne lower near Saginaw Bay perhaps
the best shot?). However, best instability (south) and best shear
(north) will be separated from each other. Svr environment looking
increasingly charged w of Lake MI tomorrow, but not so impressive
here, at least for now.
Max temps hindered somewhat by cloud cover, mainly upper 70s to mid
80s. A few upper 80s possible in the far se.
&&
.SHORT TERM...(Sunday night through Tuesday)
Issued at 337 PM EDT Sat Jun 10 2017
...Thunderstorms Sunday Night possibly Severe...
High Impact Weather Potential...Marginal severe risk Sunday
night.
Pattern Synopsis/Forecast...Flat 500 mb ridge with convergence over
Lake Superior and the UP, will be the main focus on what looks to be
MCS development from Sunday afternoon over Minnesota and Wisconsin.
The models aren`t exactly in alignment with the scenario as the
ECMWF puts convection into N Lower during the day on Sunday and
lingers into Sunday evening. While the GFS puts showers over the
region that linger a bit in N lower, while shifting the focus to E
Upper. After 06z, another piece of energy pushes into NW Ontario
forcing some troughing into W Upper which then pushes into NW Lower.
Thunderstorm activity lines up on a the sfc trough and weak cold
front overnight. Monday morning, the front is stretched out over the
region, but the shortwave trough that caused the ridge to buckle a
bit, moves east and the ridge rebounds. This leads to maybe some
showers initially over N Lower. However, for Monday afternoon, the
front that is stationary gets moisture and heat pumped into it, and
the RRQ of the 50-60 knot 500 mb jet streak to get things energized
over N lower.
Primary Forecast Concerns...With the flat, fast flow, any ripple in
the 500 mb flow could produce showers and thunderstorms. If the
models are wrong on the strength of a speed max, it could be more or
less than advertised now. At this point the chance pops
characterizes the confidence in the convection. This is going to be
a "wait and see" type of situation as until we see the convection
form and how it affects the 500 mb/sfc frontal pattern.
.LONG TERM...(Tuesday night through Saturday)
Issued at 337 PM EDT Sat Jun 10 2017
High impact weather potential...Thunderstorms possible at times
through Thursday.
Active weather is expected through mid-week as an H5 cutoff low and
attendant surface low lift through the Dakotas, continuing through
Hudson Bay late in the week. Wednesday and Thursday continue to look
the most favorable for storm development as we sit in the warm
sector. Storm activity will be suppressed once the cold front comes
through, which right now looks to be late Thursday as the surface
low pushes into Hudson Bay. Temperatures will run above normal
through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 1145 PM EDT Sat Jun 10 2017
Windy surface conditions and LLWS will persist into the overnight
hours...but will begin to diminish as we head toward daybreak in
response to a loosening of the low level pressure gradient. Mainly
clear skies will give way to increasing low level clouds overnight
into Sunday as low level moisture quickly increases ahead of the
approaching low. Chances of showers and thunderstorms will also
increase overnight into Sunday...with the best chances initially
across NW Lower Michigan (PLN/TVC/MBL).
&&
.MARINE...
Issued at 337 PM EDT Sat Jun 10 2017
Unseasonably strong low pressure nw of Superior will move quickly
ene-ward thru tonight. Strong sw winds will continue thru this
evening, diminishing overnight. Gales/small craft advisories will
continue. Southerly winds will increase again Sunday night, though
not as to the degree as today.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...BEACH HAZARDS STATEMENT until 6 AM EDT Sunday for MIZ015-020-025-
031.
LH...SMALL CRAFT ADVISORY until 6 AM EDT Sunday for LHZ345>349.
LM...GALE WARNING until 6 AM EDT Sunday for LMZ341-342-344>346.
SMALL CRAFT ADVISORY until 6 AM EDT Sunday for LMZ323.
LS...GALE WARNING until 6 AM EDT Sunday for LSZ321-322.
&&
$$
UPDATE...MLR
NEAR TERM...JZ
SHORT TERM...JSL
LONG TERM...ALM
AVIATION...MLR
MARINE...JZ
Area Forecast Discussion
National Weather Service Denver/Boulder CO
855 PM MDT Sat Jun 10 2017
.UPDATE...
Issued at 855 PM MDT Sat Jun 10 2017
Only minor updates to the winds this evening and overnight as a
strong mesoscale low deepened across the Denver metro area this
afternoon and wobbled a bit through this evening before filling
given the loss of daytime heating. East and southeast winds to
the north of the cyclone across the northern Plains of Colorado
should weaken by midnight as the pressure gradient relaxes. West
of the cyclone west winds should exist roughly from just east of
Denver into the mountains and foothills. New wind grids reflect
this.
Something to watch for Sunday afternoon is that both the RAP and
NAM generate a good amount of instability (MUCAPE ~1500 J/kg,
MLCAPE ~900 J/kg) across the I-25 metro corridor, along with some
convective precipitation along the northern foothills and
adjacent Plains. Model soundings look too wet so at this time
will not increase PoPs. The models assume surface dewpoints in the
low to mid 40s Sunday afternoon along I-25. Seems quite overdone
given current observations and HRRR trends for tomorrow.
Regardless, cloud cover should be greater Sunday compared to
Saturday and keep temps cooler most areas other than the far NE
Plains.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 352 PM MDT Sat Jun 10 2017
The cold front that is pushing south and west across the plains
has slowed down considerably early this afternoon. Temperatures
behind the front are in the 85 to 90 F range with 45 to 50 F dew
points. South and west of the front, readings are in the mid 90s
F with dew points in the upper 20s to mid 30s F. The easterly
winds are pretty brisk as well behind the front. Models have
southwesterly flow aloft for the CWA tonight and Sunday. There is
benign synoptic scale energy for the CWA tonight and Sunday. The
low level pressure and wind fields have a drainage/downsloping
combination overnight, then more easterlies on Sunday. For
moisture, it is pretty dry overnight, with some over the mountains
and foothills by Sunday afternoon. The precipitable water values
are in the the 0.25 inch west to 0.75 inch northeast range
tonight and Sunday. Low level dew point readings are in the 20s to
30S F for much of the CWA, with 50S F over the northeastern
quarter over the CWA. There is no measurable rainfall for the CWA
tonight and Sunday morning, then a tad on the ECMWF and GFS
Sunday afternoon. There is a pretty decent cap in place on the
lapse rates fields in the mid levels this evening and again Sunday
afternoon. It is awfully warm aloft. No pops. For temperatures,
Sunday`s highs look to be 1-4 C cooler than this afternoon`s.
.LONG TERM...(Sunday night through Saturday)
Issued at 230 PM MDT Sat Jun 10 2017
The atypical deep closed upper low spiraling over the central Great
Basin as of 12z/Monday is progged by the GFS, ECMWF, NAM, Canadian
and UKMet to track northeast and be over southern Idaho/northwest
Wyoming by Monday evening. This places Colorado under an abnormally
strong, very warm and dry southwest flow aloft. Concurrently, models
indicate strong pressure falls along the lee of the Front Range
south of a deep surface low which models show forming near Fort
Collins. As a result should see strong and gusty south-southwest
winds for the high mountain parks, particularly Middle and South
Parks, the Front Range mountains, in the foothills roughly south of
I-70, and on the plains generally along and south of I-76. Could see
peak gusts anywhere from 45-55kts on the higher mtn ridges, and from
32-38kts on the mtn valley floors, southern foothills, Palmer Divide
and nearby plains. If if were not for the wet/green fuels out there,
the wildland fire danger would be much higher with the anticipated
gusty winds, low RH and very warm temperatures. As it stands, do not
plan to hoist a fire weather watch, but will stress the hot and
gusty conditions in the Fireweather forecast synopsis. By late
afternoon Monday, with the upper low passing to our northwest, and
the sfc low lifting into the Nebraska panhandle, a number of the
models indicate patchy light QPF from isolated t-storms over the
northern Front Range. At the same time, the gusty winds on the
plains spread north to the Wyoming line and remain gusty til mid-
evening. Overnight, winds shift to westerly with cyclogenesis in the
Nebraska panhandle and with a cold front slipping south, winds shift
to nwly and usher in cooler air. Expect to see 10-14 deg F cool down
in max temps.
Tuesday-Wednesday...the upper trough, somewhat weaker at this point,
slips north of Colorado. The cool down on Tuesday should moderate
some on Wednesday with a return to a west-southwest deep layer flow.
Could see a few instability showers/t-storms over the high terrain
both afternoons, and really nothing to speak of on the plains.
Thursday into Friday...the upper trough moves shift of the region
and an upper ridge begins building slowly over the Great Basin.
Warmup will be gradual and precip chances essentially nil both
days.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 855 PM MDT Sat Jun 10 2017
VFR conditions with no precipitation expected through Sunday
evening at all three TAF sites. Winds will be the main forecast
issue. A multitude of surface boundaries approached or crossed
the KDEN airfield this afternoon and early evening, associated
with a mesoscale cyclone that developed along the frontal
boundary from midday today. Strong heating with temps in the 90s
deepened the cyclone late afternoon across the southwest part of
metro Denver. With the loss of heating the cyclone has filled
significantly and the pressure gradient has relaxed. Currently the
low is just northeast of KDEN resulting in west and southwest
winds across the airfield. Expect those winds to continue much of
the night but with speeds 10 kt or less tonight not expecting any
impacts. At APA and BJC wind have also come come quite a bit and
will remain that way tonight, generally out of the WNW at BJC and
SW at APA.
On Sunday diurnal east winds 8-12 kts should kick in at the TAF
sites after 16Z and continue throughout the afternoon and evening.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Schlatter
SHORT TERM...RJK
LONG TERM...Baker
AVIATION...Schlatter
Area Forecast Discussion
National Weather Service State College PA
1001 PM EDT Sat Jun 10 2017
.SYNOPSIS...
Summer heat and humidity will build over central PA through
early next week. A modest cooling trend is expected during the
second half of the upcoming week accompanied by an increasing
risk for showers and thunderstorms.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
Flat upper ridge building through central and eastern GLAKS
tonight with mainly thin cirrus traversing the region
overnight. Dry and warm conditions will prevail along with the
mostly clear skies, and min temps will range from the upper 50s
to low 60s in most areas. Some patches of fog are expected
around daybreak mainly over the lower Susquehanna Valley where
winds/dewpoints should be lightest/highest.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Sunday will be very warm with plenty of sunshine with max temps
in the mid 80s to around 90F. Dewpoints creeping into the low
60s will result in max heat index values in the low 90s over
much of the Susquehanna Valley. Another mainly clear and warm
night with mins 60-65F.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
The medium range will feature below normal heights over the
western US and above normal heights over the east, through about
the middle of next week when the pattern becomes more zonal but
with the 500mb heights remaining above 5800dm through the end of
the week. This will equate to an extended period of summer-like
warmth with dewpoints well up into the range where most will
feel uncomfortable.
The warmest temperatures will be early in the period through
midweek, with heat indices in the 90s being common over much of
the central and eastern zones (and even approaching 100F in
parts of Susq Valley). Air conditioner weather.
Precip chances will remain low under the ridge until a weak
back door cool front approaches from the north and brings a
chance for showers and thunderstorms Tuesday. I kept chances
low given good model agreement that we will remain rather warm
in the mid levels through the day Tuesday, despite heat and
humidity making for robust model CAPES. Slightly colder temps
aloft bring best chance for showers/tstms to the NE counties.
A better chance for showers/storms will present itself for
Wednesday as the same front lifts back across the area as a
warm front. Humidity throughout the eastern US will be on the
rise as a southerly flow establishes on the west side of the
high pressure that will set up along or just off the east coast.
This will lead to a very familiar summer-type forecast of hazy-
warm and humid conditions with the chances for mainly diurnal
showers and thunderstorms.
The increasing cloud cover and chances for precip toward the end
of the extended will knock a few degrees off daytime highs, but
overall temperatures will average above normal for the next
week.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
High pressure building along the east coast will bring with it a
high confidence in widespread VFR conditions through Sunday.
Clear skies and light winds may result in patchy fog around
daybreak Sunday across eastern Pa, but coverage will be limited.
A blend of latest HREFV2, LAMP, downscaled NAM and HRRR suggests
about a 25 pct chance of a brief vis reduction at IPT and even
less chance elsewhere.
.OUTLOOK...
Mon...No sig wx expected.
Tue...Scattered PM tsra impacts possible, mainly north.
Wed...Scattered PM tsra impacts possible, mainly south.
Thu...No sig wx expected.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Steinbugl
NEAR TERM...DeVoir/Steinbugl
SHORT TERM...Steinbugl
LONG TERM...RXR
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Dodge City KS
610 PM CDT Sat Jun 10 2017
...Updated aviation discussion...
.SHORT TERM...(This evening through Sunday)
Issued at 224 PM CDT Sat Jun 10 2017
RAP today had some 0-1km moisture convergence at 21z Saturday and
00z Sunday along the dry line which will be located near Garden
and Liberal with good mid level instability in place. Shear around
20 knots, high LCL, and large DCAPE was forecast also so if
storms can overcome the warm mid level temperatures these storms
could produce some gusty winds early this evening. Currently
however am unsure if anything will develop this evening given the
warm temperatures forecast in the 750 to 600mb level late day. RUC
suggests to erode this cap then temperatures need to be
approaching 104. Will wait and see but think the cap will hold.
Sunday will be a similar story when it comes to precipitation
chances for western Kansas. 0-1km moisture convergence improves by
21z Sunday as mid level instability improves to greater than
1500j/kg. NAM and GFS model soundings continue to indicate a small
amount of cin present late day as an upper way forecast to cross
the Western High Plains. CIN appears slightly stronger than today
but not by much. Could once again have a few isolated storms but
at this time will be continuing to keep the forecast dry at this
time.
Given the 850mb to 700mb temperature trends from 00z Sunday to
00z Monday it will be another day with temperatures +100 west of
the dry line. East of the day line highs will be mainly in the
middle 90s.
.LONG TERM...(Sunday night through Saturday)
Issued at 224 PM CDT Sat Jun 10 2017
Based on 850mb temperature trends early next week the heat will
continue through at least Monday with highs once again approaching
100 west of the dry line which will still be located over western
Kansas. Another subtle wave is forecast to precede the main upper
level system Monday night and will have to wait and see if any
storm may be able to break the elevated warm layer over western
Kansas. At this time will continue to follow the dry forecast.
The better chance for convection along the dry line and possibly
along an approaching cool front will be late Tuesday as a stronger
upper level system moves out into the Western High Plains. The
better forcing, moisture, and instability will be along the dry
line so focused the better chances for convection here. Ahead of
this approaching cold front it will be another hot day although
850mb temperatures at 18z Tuesday and 00z Wednesday were a couple
of degrees cooler compared to those at 00z Tuesday.
On Tuesday there will also be a chance for severe weather along
and ahead of this dry line with large hail and damaging wind gust
being the main hazard Tuesday evening. Exactly where this boundary
will be is still unclear given that this is still several days
out so will favor staying with the latest models for now. These
models placed the dry line and the better chances for these severe
storms near and east of highway 283.
As the upper low lifts northeast into the northern Rockies
towards mid week and westerly down slope flow is expected to
develop across the Central Plains. Given this set up am unsure how
far south this cold front will move on Tuesday before stalling
out. Also do not think much of a cool down will occur mid week
with this frontal boundary should if move into southwest Kansas.
The chance for scattered thunderstorms will improve late week
near and north of this surface boundary as at least two upper
level waves embedded in the west to northwesterly flow crosses the
Western High Plains late Thursday and late Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 610 PM CDT Sat Jun 10 2017
A strong low level jet is expected to develop after sunset and
continue through the night over the southwest Kansas terminals.
This will also keep surface winds gusty at times overnight.
Otherwise, VFR conditions are expected to prevail.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 96 70 98 / 0 10 0 10
GCK 70 103 68 100 / 10 10 0 10
EHA 67 102 64 98 / 0 10 0 10
LBL 70 103 68 100 / 10 10 0 10
HYS 72 99 72 98 / 0 0 0 0
P28 71 93 72 95 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Duluth MN
701 PM CDT Sat Jun 10 2017
.UPDATE...
Issued at 700 PM CDT Sat Jun 10 2017
The surface front stretched through the tip of the Arrowhead to
Ashland to just east of Siren and south. There has been some
deeper convection over the Arrowhead to the Apostle Islands but
not much further south. It`s still possible a strong to severe
storm could develop ahead of the front over northwest Wisconsin
through about 03Z.
The wind has diminished over northwest Wisconsin and the Wind
Advisory has been cancelled.
&&
.SHORT TERM...(This evening through tonight)
Issued at 310 PM CDT Sat Jun 10 2017
The focus remains on the threat of severe weather associated with
the passage of a cold front today. It still looks like storm
development will most likely hold off until the late afternoon or
early evening, when the cold front is entering the Arrowhead and
northwest Wisconsin. There is increasing confidence in the severe
weather potential for the storms do develop in northwest
Wisconsin. The Storm Prediction Center increased the risk of
severe weather to a slight risk, over areas of northwest Wisconsin
generally along and east of a line from Bayfield, to Hayward, to
Shell Lake.
The Northland had a blast of hot air amid gusty south-southwest
flow today. This flow was ahead of an approaching cold front from
the west. Temperatures, as of the middle of the afternoon, had
climbed well into the 80s and even some low 90s. Low-level mixing
and strong flow in the mixing layer was causing widespread wind
gusts of 25 to 40 mph east of the cold front. Some areas of
northwest Wisconsin had gusts to around 45 mph, and there had been
reports of fallen trees and power lines, which had sparked some
fires. Dew point temperatures had increased to the middle 60s. It
could be described as the Northland`s hottest day of the year thus
far. The cold front, which was associated with an area of low
pressure in far northwest Ontario, stretched south through north-
central and central Minnesota. Gusty and drier westerly flow was
following up the cold front. A 120 knot upper-level jet streak was
over southern Manitoba and far northwest Ontario, with fairly
strong west-southwest flow across the Northland.
This cold front will continue shifting east through the Northland
this evening, and is expected to exit the southeastern forecast
area before midnight. The warm and humid airmass will continue to
build up MUCAPE ahead of the cold front, but capping and the lack
of large-scale forcing will make it difficult to get thunderstorm
development along the cold front until later in the day. The one
exception may be up near the international border area, from
northern St. Louis County into the Boundary Waters. There has been
some erosion of the capping, and weak storms had already developed
north of the Canadian border. Some storms might develop across
into the Minnesota side of the border as the cold front moves
east. There will be some modest large-scale forcing when the
front enters northwest Wisconsin and the eastern Arrowhead very
late this afternoon and this evening. The extra support to trigger
storms will cause ramp up the chances of chances around that time
for those areas of northwest Wisconsin. Severe weather is
certainly possible at that time. The storms will be developing in
an area of ample instability and strong deep layer wind shear,
especially areas of northwest Wisconsin near and east of a line
from about Bayfield, to Hayward, and Shell Lake. There will likely
be about 1500 to 2500 J/kg of mixed layer CAPE and about 45 to 55
knots of 0-6 km bulk wind shear. This environment will be
conducive for the development discreet supercells during the
initial stages of convection. Strong updrafts could produce tall
storms capable of producing large hail, perhaps up to the size of
golf balls, despite the high freezing levels around 15000 feet
above ground level. Strong flow in the mixing layer and aloft will
boost the threat of damaging wind gusts with these storms.
Precipitable water values around 1.5 inches will support heavy
rainfall rates. There is also a threat of tornadoes with these
supercells, too, considering about 20 to 25 knots of 0-1 km bulk
shear.
The initial storms might transition into bows and line segments as
the outflow from the storms helps trigger convection. This means
the main threat of the severe weather might transition from
discreet supercells with all kinds of severe weather, to more of a
threat of damaging winds as the storms progress farther east in
northern Wisconsin.
While the previous paragraphs paint a picture of really bad
weather for northwest Wisconsin today and this evening, there is a
still the possibility there could be little if no development
along the front as it moves through northwest Wisconsin. There are
still some models downplaying convection, such as the NAM12, GFS,
and European. The higher resolution models, though, like the HRRR
and RAP, have consistently been developing storms over northwest
Wisconsin for the last 6 hourly runs or so.
The threat of storms should fully exit the far southeast corner of
the forecast area, the Price County area, before midnight as the
cold front exits the region. Drier air will filter into the
Northland in the wake of the cold front, providing clear skies
tonight. Very light wind speeds will develop. Fog chances will be
very low, expect in some areas of northwest Wisconsin that get
significant rain from storms this evening. That added soil
moisture may be just enough to produce some fog. Overnight lows
will be in the 50s.
.LONG TERM...(Sunday through Saturday)
Issued at 310 PM CDT Sat Jun 10 2017
A rather active pattern appears to be in place across the
northern tier of states for much of the upcoming week, which
should be supportive of several bouts of thunderstorms and the
associated potential for severe weather.
Chances for thunderstorms and associated severe weather/heavy
rainfall potential are expected to be rapidly increasing from
southwest to northeast on Sunday as a strong low level warm/moist
advection pattern translates east-northeastward along a quasi-
stationary frontal boundary that is expected to be located from
eastern South Dakota to northwest Wisconsin. Rapid return of
moisture and instability (CAPE >300 j/kg in the warm sector)
driven by the low level jet underneath steep mid level lapse rates
superimposed with >45 knots of deep layer shear seems to suggest
a very favorable set up for severe weather on Sunday. The primary
uncertainty at this time appears to be the timing, and to a lesser
degree, convective mode.
With that said, most of the latest model guidance (supported by
operational experience) seems to be converging to an MCS emerging
out of the eastern Dakotas sometime late tonight or Sunday
morning, and then continuing to ride along and north of the
surface-925 mb warm frontal zone along the nose of the low level
jet and CAPE gradient into east central Minnesota and eventually
northwest/north central Wisconsin. If this scenario plays out, the
convective mode would support the primary threat being damaging
winds, with a least some threat of moderate/high end damage
potential given the degree of instability/shear and large scale
support. The strength of the deep layer shear would also strongly
support embedded supercellular elements, with an attendant risk of
very large hail and perhaps a low risk of a few tornadoes and/or
high end wind damage with the most highly organized parts of the
MCS. As with any convection with this high if precipitable water
availability, the risk of heavy rainfall and flooding will also be
present.
While large scale support does not appear overly favorable
Monday- Tuesday, the DLH CWA will remain on the northern periphery
of the CAPE axis over the plains, and underneath moderate to
strong westerly flow aloft. As is often the case in June, with
this set up, almost any weak disturbance translating eastward in
the faster flow aloft will have the potential to produce
thunderstorms.
A better chance for organized, and once again strong to severe
storms, seems likely somewhere in the region during the middle
part of the week as another large scale trough moves into the
northern plains and western Great Lakes region Tuesday
night/Wednesday. This system appears as though it will be
accompanied by very strong instability and sufficient shear for
severe storms, but the exact location/timing/mode this far out, is
of course, highly uncertain at this time.
After the mid week system moves northeast, much of the northern
plains/western Great Lakes will be underneath west-northwest flow
aloft, with at least some instability present into next weekend.
Initially, deep layer subsidence behind the mid week system may
limit chances for thunderstorms, but at least some risk for
additional storms is expected to persist into next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 700 PM CDT Sat Jun 10 2017
A cold front stretched from the tip of the Arrowhead through
Ashland to just east of Siren and south early this evening. Gusty
westerly winds have developed behind the front with southwest
winds ahead. There still may be some thunderstorms that form ahead
of the front through about 03Z. VFR conditions are expected for
most areas through the period with a couple exceptions. There may
be patchy fog later tonight as winds diminish. Lower ceilings will
also be possible across southern portions of the Northland on
Sunday as more thunderstorms will be possible there. Thunderstorms
are expected to develop over South Dakota later tonight and they
will move east to northeast through the day Sunday. At this time,
we think they will affect KBRD and KHYR and possibly KDLH. We
included thunderstorms in the forecast there tomorrow but there
will likely need to be some refinement to the timing. Heavy rain
and a period of strong wind will be possible with the storms.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 57 74 54 79 / 10 70 40 10
INL 52 79 53 79 / 0 10 20 0
BRD 57 76 57 83 / 20 70 20 10
HYR 58 82 60 84 / 40 70 70 20
ASX 59 78 56 79 / 30 70 70 10
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Small Craft Advisory until 9 PM CDT this evening for LSZ121-
140>148.
&&
$$
UPDATE...Melde
SHORT TERM...Grochocinski
LONG TERM...Miller
AVIATION...Melde
Area Forecast Discussion
National Weather Service Glasgow MT
907 PM MDT Sat Jun 10 2017
.SHORT TERM...for northeast Montana...tonight through Mon...
Latest Update...
A few tweaks were made to winds and overnight low temperatures.
While occasional gusty winds may occur near showers, expect them
to prevail at around 10 mph overnight. Otherwise the forecast
remains in shape with showers gradually diminishing over the area.
Much of this activity has been in the form of virga anyways, and
dry weather conditions are expected into Sunday. Maliawco
Previous Update...
Pops were adjusted in the near term based on radar reflectivity
observations and current trends. Much of this is likely virga
though isolated to widely scattered showers are certainly possible
this evening across portions of the CWA, mainly before dark.
Otherwise the forecast remains on track. Maliawco
Previous Update: Made a quick updated to end the lake wind
advisory for Fort Peck Lake, as winds have decreased across the
lake. Gilchrist
Previous discussion: The short term starts out with generally
pleasant conditions, albeit a bit windy across the region. Fair
weather cumulus are spreading across the region as the airmass
modestly destabilizes. While not expected to be widespread, some
of the short term models, such as the HRRR and NAM, are producing
some chances for precipitation in the south and southwest this
evening. The source seems to be that the models are hinting at a
small shortwave embedded in the general southwest flow. Combined
with some signal of increasing potential instability due to
increasing Theta-E values and some signal of mesoscale cyclonic
vorticity advection within the shortwave, elevated showers will be
possible in the southwest this evening.
Tomorrow looks to generally be dry throughout the region, with
continued westerly winds that are somewhat weaker than today, and
minimum RH values generally similar to today. Thus, fire weather
concerns do not currently look to necessitate any headlines during
the short term.
A closed upper-level low pressure system is expected to begin
swinging up into Montana by near the end of the short term
period. Ahead of the low, a weak frontal system, which could very
well be the leading warm front of the larger cyclone, passes
through the region and flips the winds to east to southeast
throughout the region by Monday morning. As the low swings up from
Nevada/Idaho, precipitation will spread up from the south and
into the region early Monday in conjunction with the frontal
passage. The bulk of the potential precipitation with the system,
however, will be held off until the beginning of the extended
period.
Bigelbach
.LONG TERM...Mon night through Sat...
12z models didn`t change things too much from the previous
forecast. One thing that stands out is that severe thunderstorm
chances seem slim. Also, models continue to trim rainfall amounts.
The ECMWF was drier than the GFS. Since the models tend to
overshoot the amounts during this period, think that the ECMWF is
the better solution. Looks like amounts Monday Night and Tuesday
will generally be from 0.33 in the southeast zones to 0.75" in the
northwest.
Main deviation from Forecaster Builder solution was to raise pops
where qpf was GTE 0.25". Rest of forecast looked good. TFJ
Previous Discussion...
Upper low off the Pacific Northwest coast expected to rotate into
the Great Basin over the weekend and then lift northeast across
Montana during the early part of next week. The slow moving low
pressure system has the potential to bring much needed significant
precipitation to eastern Montana from Monday through Wednesday.
Scattered showers and a few thunderstorms expected to develop
Sunday night over southern Montana under the area of difluence
ahead of the upper low. These showers will spread north during the
day on Monday before organizing into a precipitation shield Monday
night as the stacked low lifts toward Montana. Models in good
agreement with the track and positioning of the low. More
uncertainty centers on the impact of the dry slot as it pushes
into the southeast corner of the state.
Low lifts across the northern plains and into southern Manitoba
Tuesday night and Wednesday with precipitation tapering off from
the southwest. The rest of the week features nearly zonal flow
across the northwest corner of the country. This will bring
generally dry conditions and nearly normal temperatures with a
slight warming trend. Ebert
&&
.AVIATION...
VFR.
Mid-level clouds (AOA 8K FT AGL) will move in tonight from the
southwest and linger into Sunday.
Winds: West winds will quickly diminish by sunset and are expected
to be lighter Sunday.
Outlook: Rainshower chances increases Monday with IFR ceilings
late Monday Night and Tuesday. TFJ
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Grand Rapids MI
1140 PM EDT Sat Jun 10 2017
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 314 PM EDT Sat Jun 10 2017
Most of the area will see dry conditions persist through Monday
along with hot conditions. There will only be a slight chance of a
shower or storm late tonight/Sunday and again late Monday/Monday
night mainly across Central Lower Michigan.
Better chances for rain will come for the second half of the week
along with slightly cooler temperatures as a system slips down into
the area.
&&
.UPDATE...
Issued at 1005 PM EDT Sat Jun 10 2017
The air mass remains very dry with Pwats only around 0.50. However
very late tonight (after 4-5 am), much higher Pwats over 1.5
inches come into the area from the northwest. Latest HRRR guidance
indicates that a band of moisture/instability in the 850-700 mb
layer will impact areas like Ludington/Pentwater/Baldwin toward
daybreak. Will therefore keep the chance pops going in the nrn
CWFA very late tonight into Sunday morning, with a few isolated
tstms possible since the 850-700 mb cape is shown to increase to
1000-1500 J/KG with the arrival of the higher axis of theta-e air
from the northwest.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 314 PM EDT Sat Jun 10 2017
Our main concern through the short term is pcpn chances from late
tonight through the end of the period on Mon night. We are thinking
that chances are fairly limited, and mainly across Central Lower.
Most of the time we will see limited cloud cover with hot conditions.
The first chance of rain across the northern section of the CWFA
will come as early as the pre-dawn hours on Sun. A cold front
extending from Ontario down through MN will try to push into Nrn
Lower overnight. Showers and storms ahead of it will try to make it
into the area, but will likely dissipate before making it. This is
due to the fact that the low level jet and supporting wave will be
well north of the area. Still can not rule out a few light
showers/sprinkles making it in up north.
Some small storm chances will linger through Sunday across the area.
The front will be just north of the area, however we are expecting
an MCS across WI could ride along this front, and potentially clip
the nrn section of the area as it is dissipating. It will be riding
into a fairly unstable area (CAPEs of 1000-2000 j/kg), but quite
capped, and will likely ride the edge of the cap.
Rain chances will drop a bit lower then for Sun night and Mon as the
front is expected to push a bit further north. This will be the
result of a wave that will riding NE into Canada and should stay NW
of the area. The chances will then increase a little bit Mon night
as the wave that rides NE Sun night and Mon will drag the front
south a bit behind it. The front could make it down to around I-96.
Max temps the next couple of days have the potential to warm a
couple of degrees each day, with 90s likely by Monday as H850 temps
approach 20C. This would be assuming little to no rainfall.
.LONG TERM...(Tuesday through Saturday)
Issued at 314 PM EDT Sat Jun 10 2017
Little question summer like weather will prevail most of this coming
week before a return to cooler conditions comes in the following
week. It will largely be dry Tuesday into Wednesday but later
Wednesday into Thursday is when there is the best chance for most of
the area to see a significant rainfall event. This happens due to
widespread thunderstorm activity associated with the cold front. It
should dry out Friday into Saturday but it will remain seasonably
warm. More storms are possible later in the weekend.
We still have our three storms over the north Pacific from Japan too
the west coast of the United States. Plus our polar vortex like
circulation over northern Hudson Bay. The hot weather we are
expecting from Sun through Wednesday is from the lead storm coming
on shore (happening as I write this) but it is trapped by an omega
block due to next storm currently near the tip of the Aleutian
Islands and a closed upper high between them. By early next week the
second storm finally boots the first storm northeast into Southern
Canada, shearing it out over the top of the upper ridge over the
eastern United States. It is that lead system being sheared out that
brings the thunderstorms later Wednesday into Thursday.
Since there is two more systems behind that one, the second storm
gets booted into western Canada by the third system (which by Friday
is near the dateline). That system being booted into western Canada
will keep the eastern upper ridge from totally breaking down and
thus prevent it from cooling off much behind the front. It is not
until early in the following week when the third system gets close
enough the the United States to force the second system to dig
southeast into the Great Lakes that the really cool air finally
comes back to this area. More storms are possible next weekend as
that second system starts to dig into the northern Plains and Great
Lakes.
&&
.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1130 PM EDT Sat Jun 10 2017
Vfr conditions will continue through Sunday evening. We will
continue to carry LLWS in the terminal fcsts overnight due to wind
speeds of around 45 kts at 2000 ft. Southwest winds will increase
to 15 to 20 kts with gusts to 25 kts at all the terminals Saturday
morning and afternoon before gradually subsiding Saturday evening.
&&
.MARINE...
Issued at 1005 PM EDT Sat Jun 10 2017
Extended the Beach Hazard Statement and Small Craft Advisory
through Sunday as south flow looks to remain strong enough to
continue to support hazardous conditions on the lake. The Gale
Warning for the northernmost marine zone off Ludington remains in
effect and will be replaced with a Small Craft Advisory once peak
winds settle down below 35 knots.
&&
.FIRE WEATHER...
Issued at 314 PM EDT Sat Jun 10 2017
Fire danger remains elevated this afternoon due to the dry and windy
conditions. Aside from a local area approaching Red Flag conditions,
RH`s are remaining just a tad too high to justify a warning at this
time. Winds will not be as bad, and RH`s will be similar on Sunday.
&&
.HYDROLOGY...
Issued at 151 PM EDT Sat Jun 10 2017
There are no changes from the last update. There are no concerns
for flooding at this time. Chances for rain are low/zero through
Tuesday. Rain chances may finally increase through the middle of
next week. Convective precipitation may result in localized heavy
rain at time, but prolonged heavy rainfall does not look likely.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement through Sunday evening for MIZ037-043-
050-056-064.
LM...Gale Warning until 5 AM EDT Sunday for LMZ849.
Small Craft Advisory until 8 PM EDT Sunday for LMZ844>848.
&&
$$
UPDATE...Meade
SYNOPSIS...NJJ
SHORT TERM...NJJ
LONG TERM...WDM
AVIATION...Laurens
FIRE WEATHER...NJJ
HYDROLOGY...JAM
MARINE...Meade
Area Forecast Discussion
National Weather Service Jacksonville FL
850 PM EDT Sat Jun 10 2017
...HEAVY AND LOCALLY FLOODING RAINFALL RETURNS...
.UPDATE...Rainfall returned with a vengeance to inland locations
this afternoon including Marion county where flash flooding due to
rainfall accumulations of 3-5 inches within an hour in some areas
caused major street flooding and a large sinkhole along State
Road 200. A surface front lifted northward up the north- central
Florida peninsula with a return of deep moisture with precipitable
water rising to above 1.8 inches per the 00Z JAX RAOB. Low level
ESE flow undercut upper level WSW flow within the southern stream
jet. Upper level divergence, high moisture, slow storm motion,
diurnal heating all contributed to locally heavy rainfall...with
this pattern expected over the next several days.
Recent HRRR guidance started to pick-up better initializing
coastal showers within convergent bands setting up over our
Atlantic waters while inland convection near and west of I-75
continued to fade and drift farther west. Updated the forecast to
include coastal showers through the night with the low level
trough axis meandering over the local area and upper level
divergence and high moisture content continuing to stream
overhead.
Muggy overnight conditions under mostly cloudy skies are expected
with low temps falling into the low/mid 70s.
&&
.AVIATION...Coastal convection and low stratus will be possible
early Sunday morning under onshore flow. Inland rainfall was
dissipating at GNV this hour. SREF indicated potential for MVFR
cigs moving inland from the Atlantic 09Z-12Z with a very low
chance of IFR to potential LIFR near SGJ and GNV around sunrise
(probabilities <15%). At this time will continue to trend toward
MVFR cigs for coastal sites tonight. Will also continue with VCSH
at coastal terminals tonight. Highest confidence for TS included
at GNV Sunday after 17Z. Locally heavy rainfall and wet downbursts
will continue to be largest concerns.
&&
.MARINE...ESE winds 10 kts or less will prevail tonight with
combined seas 3 ft or less. Updated forecast to include showers
and isolated tstorms through the night.
Rip Currents: Moderate risk this weekend due to onshore flow.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 70 89 72 88 / 20 40 20 50
SSI 76 85 75 84 / 20 20 10 30
JAX 72 87 73 86 / 20 30 10 40
SGJ 74 86 74 84 / 30 30 10 30
GNV 72 88 72 86 / 50 70 20 60
OCF 72 89 72 87 / 30 70 30 70
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Enyedi/Shuler/Peterson
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
521 PM MDT Sat Jun 10 2017
.DISCUSSION...(This Evening Through Saturday)
Issued at 205 PM MDT Sat Jun 10 2017
PAC NW Upper trough continues to support periodic impulses into
the region, supporting a wavering frontal boundary over the FA.
This will be the case through early next week, at which time the
entire upper trough will finally eject over the region and support
a vigorous storm system into the FA Monday. A shortwave trough is
taking aim on the region and will provide enough forcing in the
presence of the departing jet streak entrance region to support
elevated convection tonight across the northern 2/3 to half of the
fa. Staunch pos theta-e adv (indicated well at h7 with a bubble
of +335K air advecting over the region ahead of the mid level
trough) coupled with steep mid level lapse rates will support
support 1000-2000 J/KG of elevated CAPE. Effective bulk shear
numbers in excess of 50 knots coupled with CAPE/forcing parameters
will be more than sufficient for a few rotating updrafts,
supporting a severe threat, mainly large hail. HRRR UH tracks
certainly support this as well. Best chance for storms will be
from the central/northern Black Hills northeast out to Dupree. TS
will exit the region early Sunday morning with ll flow becoming NE
as the impulse forces pressure rises into the region.
Generally quiet weather expected Sunday during the day as weak
subsidence and ll dry NE flow supports subsidence over the region.
However, the main upper low will begin to push toward the region
Sunday night, supporting elevated pos theta-e adv over the region
esp the western third. This will likely support diurnal convection
over central/southern WY which will spread north overnight, esp
over the far western third. Low level moisture adv will begin to
slowly ramp up Monday as pos theta-e adv continues through Monday
ahead of the advancing upper low. This may support a band of
elevated convection through most of the FA moving north through
morning and possibly into early afternoon. The main show will be
Monday evening and overnight hours. Main upper trough will push
into the region, supporting strong large scale ascent, with a
potent 50-70 knot mid level jet streak. This will support
impressive bulk shear values over 50 knots with steepening mid-
level lapse rates. The main wild card will be the amount of
moisture return back into the FA, which will be the determining
factor on the intensity and coverage of expected severe weather.
Forecast models have been running a little high on ll moisture
advection with the last few systems, esp given the ongoing dry
conds. However, given expected moisture pooling along the wavering
front coupled with the weak southward surge of the ll frontal
boundary Sunday and the proximity of the FA to deeper moisture (SE
Nebraska), expect that moisture profiles should not be too far
off in current GFS/NAM progs, which should support a good chance
of supercell TS with potential upscale growth into a large severe
MCS tracking NE across the central FA (just north of the sfc low),
esp given LLJ development Monday night. Storms would likely fire
in WY (possibly just south of our FA Monday evening) and shift NE
and expand over the region Monday night. Large hail, damaging
winds, and isolated tornadoes would be possible (given highly
curved LL hodographs), with potential QLCS tendencies later Monday
night.
Cooler but mainly dry conds can be expected after Monday, with
perhaps a few diurnal showers under the upper low Tues across NE
WY. Upper flow will then trend WNW with subtle impulses in the
flow perhaps supporting slight chances for SHRA/TS at times, but
nothing to warrant a pop mention attm.
&&
.AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening)
Issued At 519 PM MDT Sat Jun 10 2017
TSRA will develop this evening across northeast WY/Black Hills
region and then spread east/northeast overnight. MVFR CIGS/VSBYS
will occur with the strongest storms along with hail/gusty winds.
Outside of TSRA, VFR conditions will prevail through the period.
&&
.UNR WATCHES/WARNINGS/ADVISORIES...
SD...None.
WY...None.
&&
$$
DISCUSSION...JC
AVIATION...Helgeson