Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/16/18
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
818 PM CDT Fri Jun 15 2018
.UPDATE...
Issued at 813 PM CDT Fri Jun 15 2018
Made a few changes this evening. CAMS are consistent in developing
an MCS on the head of the LLJ overnight. Problem is temps are
still quite warm aloft...ie +12C at H7 or higher. Due to CAM
consistency have bumped up pops a notch over mainly sc/se CWA
where LLJ should be focused late tonight. Temperatures look okay
for the most part.
&&
.SHORT TERM...(This Evening through Saturday Afternoon)
Issued at 332 PM CDT Fri Jun 15 2018
Late this afternoon, a surface frontal boundary was extending from
northeast SD and then southwest into central Nebraska. There was a
weak surface low pressure area on this boundary in northeast SD. The
issue tonight will be if the lift from a short wave trough moving in
from the southwest will be enough to overcome the warmer mid level
temperatures. Some of the models indicate this will occur with
showers and storms developing with good qpf like the gfs and hrrr
while the nam and rap13 showed little if any qpf. At any rate, there
will be plenty of instability and moisture available to the storms
if they can get going. Have in chance pops tonight/early Saturday
morning. Otherwise, there looks to be a break for Saturday morning
into the early afternoon for much of the cwa before another short
wave trough makes its way into the region for the late afternoon.
With surface heating and continued good instability, deep layer wind
shear, and cooler mid level temperatures, thunderstorms are expected
to develop. With precipitable waters getting up to close to 2 inches
with the help of the moisture from tropical system Bud, heavy
rainfall could occur with these storms.
.LONG TERM...(Saturday Evening through Friday)
Issued at 332 PM CDT Fri Jun 15 2018
The threat for heavy rainfall, as well as severe storms, Saturday
night through Sunday night will be the main concerns in the long
term. The period begins with an upper level ridge over the Ohio
Valley with southwesterly flow over this region. Remnants from
Hurricane Bud will likely bring record to near record PWATS,
especially 0Z Sunday. Both the NAM/GFS show PWATS of 1.90 inches,
which would rank in the top ten highest values for June. While not
outside the climatological mean, NAEFS return interval does indicate
the high PWATS occur once every 5 to 10 years. A possible rare
rainfall record is at stake. Remnants from Hurricane Lester in
August, 1992 produced 3.29 inches of rain in southeast SD. The 3.29
inches is the most SD has seen from a tropical cyclone since 1950.
It is possible this record could be broken Saturday through Sunday.
With a 40 to 50 knot LLJ, gradient of instability, severe storms
will be possible Saturday night into early Sunday morning.
Instability quickly wanes on Sunday with the severe threat best
south of this CWA. Conditions should dry out early next week before
pcpn chances move back into the region late next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 617 PM CDT Fri Jun 15 2018
VFR skies/vsbys are generally expected overnight. However,
thunderstorms are also possible, therefore relatively brief
periods of IFR conditions can be expected with any thunderstorms.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TDK
SHORT TERM...Mohr
LONG TERM...SD
AVIATION...TDK
Area Forecast Discussion
National Weather Service Albany NY
1003 PM EDT Fri Jun 15 2018
.SYNOPSIS...
The last upper level disturbance will push southward tonight
with clearing skies. Dry and seasonable conditions are expected
to start the weekend as high pressure slides across the region.
Then a warm front approaches the second half of the weekend
which will lead to summer like weather for early next week.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1000 PM EDT, clear skies prevail this evening with
temperatures already cooling into the 50s. No changes were made
to the forecast at this time outside of refreshing the hourly
temps.
Prev Disc...As of 740 PM EDT, latest visible imagery indicates
clearing skies this evening. This, along with light winds, will
lead to good radiational cooling and temperatures dipping into
the upper 40s to lower 50s overnight. So have tweaked sky grids
and hourly temps to reflect recent obs. Otherwise, the forecast
remains on track this evening.
Prev Disc...As of 330 PM EDT...One last short wave within our
northwest flow regime per the enhanced layered GOES-16 H2O Vapor
channels was rotating southward near or just wet of the I81
corridor. GOES-16 Visible Red channel indicates enhanced cumulus
field from the Dacks, western Mohawk Valley into the Catskills
and mid-Hudson Valley yet radar reflectivities are thus-far nil
of activity. Per HRRR and forecast profiles, still the small
window of opportunity for an isolated shower across the terrain
west of the Hudson through the balance of the afternoon hours.
As this wave tracks south this evening, increasing subsidence
and loss of daytime heating should result in a clearing sky. As
winds subside, should be a tranquil period of weather tonight as
overnight lows dip back mainly into the 50s with some upper 40s
across the higher terrain.
Saturday...The aforementioned surface high slides off the mid-
Atlantic coastline leaving behind a slight increase in those
westerly winds. There could be some convective debris in the
form of cirrus thanks to potential MCS across the upper
Mississippi River Valley that could spill over the ridge but an
overall a nice day is on tap.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
Saturday Night...As the upper ridge builds upstream and begins
to track eastward, warm front becomes a bit more defined per the
thermal packing in the lower levels upstream. NCEP Model Suite
while over similar synoptic setup, they do differ on the degree
of instability and whether enough forcing will occur for
convection to evolve along the boundary and track into eastern
NY. We will cut back the slight chance PoPs to mainly Herkimer
County and just west of the Catskills overnight at this time.
Overnight lows generally within a couple degrees of the range
between 55-60F.
Sunday (Father`s Day) will feature increasingly more humid
conditions and warming temperatures as the warm front slides
across the region. The main challenge of the day is what, if
any, convection develops or occurs along the warm front as it
progresses through. The NAM keeps things rather capped where as
the global models are a bit more robust with convective
potential. Given the strength of the increase baroclinicity and
low level jet dynamics of magnitudes approaching 30kts and
Showalter values dropping below 0C, we will retain the previous
excellent forecast of chance PoPs along and north of I90 with
slight chance to the south. Temperatures under a diverse cloud
coverage should climb into the 80s across majority of the county
warning area (CWA).
Sunday night...We become well established in the warm sector as
dewpoints climb well into the 60s and perhaps near 70F overnight
as main focus with convection should remain north of of I90.
However, as it will be rather close with frontal position and
close coordination with neighboring WFOs, we will retain the
graduated PoPs with chance along and north of I90 overnight and
slight chance to the south. A H850 temperatures approach +21C
overnight, should be rather muggy with overnight lows generally
into the 60s and lower 70s.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
A hot opener will quickly turn dry and seasonably warm. Monday
will be the second day of a hot start to the week. A cold front
sliding south through eastern New York and adjacent western New
England promises to bring showers, thunderstorms and an end to
the extreme heat by the end of the day on Monday.
High temperatures on Monday will range from around 80 degrees in the
high peaks of the Adirondacks and Greens, to the mid 90s down the
Hudson Valley, with upper 60s to mid 80s on Tuesday. Lower 80s will
be the max on Wednesday. With weak high pressure in control through
the remainder of the week, high readings will level off slightly
above normal for the balance of the work week. Lows Monday night
will range from the upper 50s to lower 70s, with around 50 degrees
to the lower 60s Tuesday night. Overnight readings will begin to
moderate somewhat thereafter.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions will prevail through the forecast period with
perhaps some passing mid or high level clouds during the day
tomorrow. Winds will be light and variable, generally less than
6 kts.
Outlook...
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SHRA...TSRA.
Sunday Night: Low Operational Impact. Slight Chance of SHRA...TSRA.
Monday: Moderate Operational Impact. Chance of SHRA...TSRA.
Monday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday: Moderate Operational Impact. Chance of SHRA.
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
An upper level disturbance will move off the New England coast
by this evening, with isolated showers ending mainly to the west
of the Hudson. Clouds will gradually decrease tonight, with
clearing skies and light winds. Conditions will become
increasingly warm and humid over the weekend into early next
week, with a chance for showers and thunderstorms returning by
Sunday as well.
RH values will increase to around 75 to 100 percent tonight.
Minimum RH values on Saturday will be around 30 to 40 percent.
Winds tonight will become northwest around 5 mph or less. Winds
on Saturday will be northwest around 5 to 10 mph.
&&
.HYDROLOGY...
No hydrological problems are anticipated into early next week.
Dry weather is expected from this evening through Saturday
night. This should allow rivers, creeks, brooks, lakes,
reservoirs, and streams levels to either hold steady or slowly
fall.
The next chance of showers and thunderstorms arrives Sunday
into Monday, as a frontal boundary approaches and slowly pushes
south across the region. With an increasingly hot and humid air
mass, some heavy downpours may occur.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM/JVM
SHORT TERM...BGM
LONG TERM...ELH/Wasula
AVIATION...Frugis/JVM
FIRE WEATHER...BGM/JPV
HYDROLOGY...BGM/JPV
Area Forecast Discussion
National Weather Service La Crosse WI
638 PM CDT Fri Jun 15 2018
.SHORT TERM...(This evening through Sunday)
Issued at 350 PM CDT Fri Jun 15 2018
At 3 PM, a mesoscale convective complex was moving through the
Twin Cities. This system was producing scattered showers and
storms across east-central, southeast, and south-central
Minnesota, and north-central Iowa. The HRRR and ARW have the best
handle on this precipitation. As the afternoon progresses, these
showers and storms will eventually build across Wabasha and Dodge
counties in southeast Minnesota and along and north of Interstate
94 in western Wisconsin late this afternoon and early evening. As
this convection builds and develops a cold pool, the HRRR pushes
it south toward Interstate 90. Considering the cap strength, this
seems a bit unrealistic, so trended the PoPs along and north of
Interstate 94. We will have to watch these storms for the
potential of an isolated severe storm. Damaging winds, hail, and
very heavy rain will be the main concerns.
As the low level jet increases the moisture transport into eastern
South Dakota, a mesoscale convective complex will develop. It will
then move northeast across southwest and central Minnesota. A few
of these storms may move through north-central Wisconsin. With
weak 2-6 km shear, any severe weather will likely be more
isolated than widespread. However, if a large enough cold pool
happens to develop, a squall line may develop with damaging winds
the main concern. Additional storms will be possible north of
Interstate 94 through the weekend.
With precipitable water values running between 1.5 and 2 inches
and warm cloud layer depths of 3.5 to 4 km through the weekend,
any storms that do develop will be capable of producing very heavy
rain.
On Saturday and Sunday afternoons, high temperatures will climb
to around 90 north of Interstate 90 and in the lower and mid 90s
across the remainder of the region. With these temperatures and
dew points around 70, afternoon and evening heat indices will
climb into the 90 to 105 degree range. Due to this, we have issued
a Heat Advisory from 1 PM Saturday through 7 PM Sunday. With
850 mb temperature anomalies around 2 standard deviations, there
may be a few record highs tied or broken. These records can be
found in the climate section below.
.LONG TERM...(Sunday night through Friday)
Issued at 350 PM CDT Fri Jun 15 2018
From Sunday night through Monday evening, a cold front will move
slowly southeast through the Upper Mississippi River Valley. Ahead
of this front ML CAPES will climb into the 1500 to 3000 J/kg.
However, the 0-3 and 0-6 km shear remains weak, so any severe
weather does happen to develop will be isolated in nature.
With precipitable water values running between 1.5 and 2 inches
and warm cloud layer depths of 3.5 to 4 km through the weekend,
any storms that do develop will be capable of producing very heavy
rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 638 PM CDT Fri Jun 15 2018
Thunderstorms continue to track just north of LSE and should
remain there the next few hours, with just some thicker "blow-off"
cirrus for RST/LSE expected. Based on current trends, it appears
additional storms will develop toward central Minnesota later
tonight, again likely missing RST and LSE and leaving VFR
conditions intact, though of course we`re dealing with convection
here and we`ll have to watch trends closely in the near term.
Winds will settle down a bit overnight, generally out of the
south/southeast 8-12 knots, allowing low level wind shear to
develop at RST. Winds will then ramp up again on Saturday, gusting
20-25 knots through the afternoon with any additional storms
likely holding north of the TAF sites.
&&
.CLIMATE...
Issued at 350 PM CDT Fri Jun 15 2018
Here are some record highs for Saturday...
Austin MN 93F in 1987
Charles City IA 96F in 1933
Cresco IA 92F in 1946
Decorah IA 97F in 1910
La Crosse WI 94F in 1994
Mauston WI 92F in 2007
Medford WI 94F in 1898
Neillsville WI 94F in 1907
Prairie du Chien WI 96F in 1987
Rochester MN 99F in 1913
Sparta WI 95F in 1918
Winona MN 94F in 1987
Here are some record highs for Sunday...
Austin MN 93F in 1995
Charles City IA 95F in 1913
Cresco IA 92F in 1940
Decorah IA 98F in 1910
La Crosse WI 95F in 1995
Mauston WI 93F in 1918
Medford WI 93F in 1907
Neillsville WI 95F in 1910
Prairie du Chien WI 96F in 1987
Rochester MN 94F in 1933
Sparta WI 93F in 1934
Winona MN 97F in 1933
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory from 1 PM Saturday to 7 PM CDT Sunday for
WIZ032>034-041>044-053>055-061.
MN...Heat Advisory from 1 PM Saturday to 7 PM CDT Sunday for MNZ079-
086>088-094>096.
IA...Heat Advisory from 1 PM Saturday to 7 PM CDT Sunday for
IAZ008>011-018-019-029-030.
&&
$$
SHORT TERM...Boyne
LONG TERM...Boyne
AVIATION...Lawrence
CLIMATE...Boyne
Area Forecast Discussion
National Weather Service Columbia SC
1007 PM EDT Fri Jun 15 2018
.SYNOPSIS...
Weak frontal boundary over the Midlands and Pee Dee will slowly
move southward today and stall near the CSRA Saturday. High
pressure and a building upper level ridge will control the
region for Sunday into late next week. This scenario will keep
chances of mainly afternoon and evening thunderstorms in the
forecast with rising temperatures through late next week.
&&
.NEAR TERM /UNTIL 7 AM SATURDAY MORNING/...
A frontal boundary/dewpoint gradient remains situated across
the Midlands. A warm moist airmass along and south of the front
has fueled thunderstorms development. Dry air aloft is keeping
coverage scattered, but it has also allowed some storms to
become severe with outflow winds around 60 mph. The strongest
storms are now located in Sumter and Clarendon County, with
isolated storms elsewhere. Converging outflow boundaries could
allow activity to persist for several more hours. But overall,
strength and coverage should continue to diminish from this
point forward with the loss of daytime heating and drier low
level air filtering in from the north.
Overnight lows will generally be in the low 70s, except upper
60s to the north.
&&
.SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/...
Upper level ridge over the MS River Valley will slowly build east
Saturday as the upper trough off the east coast moves out to sea.
The remains of a surface front will be near the CSRA on Saturday
and continue acting as a focusing mechanism for diurnal convection.
Instability will continue in the moderate to strong range with DCAPE
again around 1000 J/KG and pwat values of 1.7 inches. Still expect
afternoon and evening thunderstorms...with a better chance across
the southern Midlands and CSRA. Strong winds and locally heavy
rainfall be will the main threats. Hail potential will be lower
Saturday as wet bulb zero heights will be higher.
Saturday night through Sunday will see the upper level ridge build
over the area with the ridge axis centered over the forecast area
Sunday night. At the surface high pressure will move north of the
area Saturday night and be located offshore of the Carolinas Sunday
and Sunday night. With the remains of the front south of the area
and high pressure pushing slightly drier air into the region Sunday
and Sunday night...thunderstorm chances will be lower with slight
chance over the northern Midlands and chance farther south.
Temperatures will be in the low to mid 90s for afternoon highs with
low to mid 70s for overnight lows.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
Upper level ridge over the region Monday and Tuesday will be
suppressed south and west Wednesday through Friday as an upper
trough crosses the northeastern states. Surface high pressure
over the western Atlantic will ridge into the southeastern
states with a lee side trough over the Carolinas. Main concern
for the first half of next week will be hot temperatures with
highs in the mid to upper 90s and lows in the low to mid 70s.
Should see heat indices between 100F and 110F. Scattered
diurnal thunderstorms expected Monday through Wednesday.
Several weak short waves moving through area on the east side of the
upper ridge Thursday and Friday will increase the chance for showers
and thunderstorms for the end of next week...as a frontal boundary
drops south into the Mid Atlantic region. May see slight
cooling by Friday but temperatures will remain above normal
through the long term.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
VFR conditions expected outside of scattered diurnal convection.
A weak front remains over the area, with scattered
thunderstorms across the eastern Midlands. However, it is
unlikely the terminals will see any more activity tonight.
A 15 kt LLJ will inhibit widespread fog although cannot rule
out a brief period of visibility restriction at fog prone OGB
and AGS. Biggest uncertainty is at OGB where MAV and MET
guidance hit it hard, but HRRR keeps conditions VFR. Due to
persistence have left out of the forecast for now, but would
not be surprised to see some visibility restriction by morning.
Winds will be light and variable overnight. Easterly winds will
pick up around 15Z with a scattered cumulus deck developing
late morning to early afternoon Saturday. There will be another
chance of scattered thunderstorms, but too early to know exactly
where they will develop, so will not include mention yet.
EXTENDED AVIATION OUTLOOK...There may be restrictions in
stratus and fog during the early morning hours and also in
mainly afternoon and evening thunderstorms through Wednesday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
morning`s forecast discussion. Convection is slowly expanding on
coverage across the Pee Dee along/ahead of a weak, backdoor
cold front. Convection will gradually build/develop south with
the front as a plethora of mesoscale boundaries interact with
the sea breeze. The greatest coverage of tstms still looks to
occur across the Charleston Tri-County area into Colleton County
where the best juxtaposition of strong instability and low-
level convergence will occur. Even at this hour, it is unclear
how organized the approaching convection will become as any
organization will be highly dependent on mesoscale processes
given the weak shear profiles that are in place. Tstms will also
be fighting quite bit of mid-level dry air. Conditions will be
favorable for severe tstms with damaging winds, large hail and
frequent cloud-to-ground lightning all being possible. The risk
for severe weather looks greatest along/north of a Walterboro-
Kiawah Island line. Farther south, instability drops off
considerably, but still moderate for early summer. While an
isolated severe tstm could still certainly pop farther south,
especially along/south of the I-16 corridor there convection
approaching from the south will be the most prevalent, the
better instability and severe risk will remain confined to the
far northern areas.
For the overnight, pops will range from 60% across the
Charleston Tri-County area and Colleton County to 30-40% across
Southeast Georgia. Rain chances will steadily diminish by late
evening with mostly dry conditions expected to prevail during
the early morning hours Saturday as the backdoor cold front
approaches the Savannah River. Lows will range from the lower
70s inland to the mid-upper 70s at the beaches.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
Saturday: A cold front will stall and weaken over southeast GA. Best
moisture/instability will pool along this boundary and will support
at least scattered showers/thunderstorms mainly during the
afternoon/evening hours. Slow-moving thunderstorms could produce
locally heavy rainfall and frequent cloud to ground lightning
particularly along/south of the Savannah River. With expected
Saturday afternoon instability not as strong as Friday afternoon,
the associated severe potential should remain limited to the chance
for a couple of stronger updrafts supporting isolated/brief damaging
wind gusts.
Sunday and Monday: A building upper ridge should support hotter
temperatures and could limit coverage of mainly afternoon/evening
sea breeze thunderstorms. The latest forecasts indicate slight
chance/low chance PoPs during the afternoon/early evening hours.
Also, the severe potential appears rather low. Meanwhile, heat index
values of at least 100F are expected to increase in coverage
especially away from the beaches, and we will assess the potential
for higher heat indices/Heat Advisories, particularly starting early
next week.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Tuesday-Wednesday, an upper ridge will continue to produce a
hot/humid pattern punctuated by typical afternoon/evening
thunderstorms along the sea breeze. Then, global models indicate
that the upper ridge will gradually retrograde/shift west as a broad
upper trough over the northeast U.S./southeast Canada tries to push
southward down the U.S. east coast Thursday and Friday. Expect
rather typical isolated to scattered afternoon convection each day
through Wednesday, with possibly an increase to at least scattered
coverage during the afternoons by Thursday and Friday as upper
heights lower, and better deep layer moisture potentially moves down
from the north on the east side of the retrograding ridge. Guidance
was producing likely PoPs most of the area by Thursday and Friday,
but given the uncertainty, kept chance wording.
Temperatures will continue above normal through the period.
Highs in the lower to mid 90s, warmest inland, and lows generally in
the lower to mid 70s, warmest near the coast. Outside any
thunderstorms, daily afternoon heat indices should average at least
100-105F, and locally higher values could be realized. We will
continue to assess the potential Heat Advisories for next week.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
A large cluster of storms has developed over the
Berkeley/Dorchester County line, drifting to the SW. KCLX
indicated that a well defined outflow has departed the storm
cluster and appears to track to the SW at 25 kts. It appears
that KCHS will observed a thunderstorm at the beginning of the
Oz TAF, then should quickly dissipate with lingering stratiform
rain. At KSAV, a few showers will drifting northward, but were
quickly dissipating. After the convection, forecast soundings
and MOS indicate that VFR conditions will prevail through the
rest of the 0Z TAF period. The KSAV TAF will include a PROB30
for thunderstorms from 17Z-23Z.
Extended Aviation Outlook: With a stationary/weakening front just
south of the area, there exists the potential for later night/early
morning stratus/fog, especially at KSAV early Sunday and Monday
mornings. Also, the chance for mainly afternoon/evening
thunderstorms and associated brief flight restrictions will be
slightly greater around KSAV especially Saturday through Monday.
Otherwise, expect VFR conditions much of the time.
&&
.MARINE...
Tonight: Convection approaching from the north along a backdoor
cold front could pose a hazard to mariners late this afternoon
into the evening hours.
Saturday through Wednesday: Outside hazardous conditions
within/near any thunderstorms, expect a typical early summer
pattern to prevail. Aside from a brief wind shift to the
northeast for a few hours Saturday, expect typical daily sea
breeze/nocturnal S/SW winds and accompanying seas to remain
below SCA levels through this period.
&&
.TIDES/COASTAL FLOODING...
Current data suggest tide levels will fall just short of shallow
coastal flooding levels at Charleston Harbor. It could be close,
but a Coastal Flood Advisory is not anticipated at this time.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
NEAR TERM...NED
SHORT TERM...
LONG TERM...
AVIATION...NED
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Duluth MN
1026 PM CDT Fri Jun 15 2018
.UPDATE...
Issued at 1015 PM CDT Fri Jun 15 2018
Moved PoP maxima north towards the MN Arrowhead overnight.
Included heavy rain tags and severe potential for Saturday
morning. Latest SSEO guidance looks quite good - especially if you
throw out the -12h runs and blend with the latest HRRR. All begin
convection in the next hour or two and move it through the MN
Arrowhead overnight. Eventually this will sag south towards WI by
morning. It`ll be close, but the Duluth area may go largely
unscathed until Saturday afternoon.
UPDATE Issued at 636 PM CDT Fri Jun 15 2018
Updated aviation section below for the 00Z TAF update.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 318 PM CDT Fri Jun 15 2018
An active weather pattern will continue across the Northland
through the day Saturday, with the continued threat of severe
weather and flooding through the weekend across portions of the
Northland. The overall weather pattern has a longwave upper-level
trough situated over the Pacific Northwest, which will remain in
place. An upper-level ridge over the southeastern United States
will help to block the flow aloft, and bring multiple shortwaves
into the Northland. Moreover, a persistent low-level jet and
warm, moist southerly flow will continue to enhance moisture
transport, as evidenced by the 15.12z GFS, which shows increased
theta-e advection moving into the region, which will help to fuel
these storms. There should be plenty of instability available,
with MUCAPE values overnight, with GFS, NAM, and GEM models all
progging between 2 to 4 kJ/kg. The deep-layer shear appears to be
modest through Saturday, with values generally between 25 to 35
knots, so some organized updrafts will be possible. Pwat values
are progged to be between the 1.5" to 2.0" range, so plenty of
moisture to rain out from these storms. Due to this favorable
scenario, decided to issue a Flash Flood Watch for a good portion
of the Northland through the weekend. The high-resolution model
guidance has struggled to resolve today`s convection, so
confidence in the forecast is below average, but it appears that
there will be a general lull in the thunderstorm activity this
evening before things ramp up overnight again. There is still some
disagreements in the HRRR and NAMNest models regarding the areal
coverage of the thunderstorms, so decided to broad-brush the PoPs
for this evening and overnight. The HRRR wants to develop
thunderstorms along an approaching surface cold front, and the
NAMNest developing things along an approaching surface warm front,
so lots of uncertainty with this scenario.
Same story for Saturday, with the threat for showers and storms
through the day. There is a Slight risk of severe weather over the
southern half of our forecast area, with the main threats being
large hail and damaging winds, along with flash flood potential.
The best chances for severe thunderstorms will be in the afternoon
and evening hours as instability will be maximized. MLCAPE values
will be depended on prior convection, but values between 3 to 4
kJ/kg will be possible during the day.
.LONG TERM...(Saturday night through Friday)
Issued at 318 PM CDT Fri Jun 15 2018
A frontal boundary will remain parked over the area for Saturday
night into Sunday. Multiple vort maxes will ride along this boundary
bringing multiple rounds of storms. However, convective feedback
continues to be an issue in terms of both timing and QPF. The best
chance for severe storms Saturday evening and night look to be along
and south of Highway 210 in Minnesota and into all of northwest
Wisconsin. CAPE will be approaching 2000 J/kg depending on which
model you look at in a rather moist environment. There continues to
be a capping inversion in place with 700mb temps of 10-12C. This
could lead to elevated storms which would reduce the severe threat
somewhat. The low level jet is expected to ramp up during the
evening which will help bring more moisture into the region. PWATs
will already be around 2" and may increase to close to 2.5"
overnight. This could further the threat for flooding considering
many areas in northwest Wisconsin and parts of eastern Minnesota
will already be saturated by earlier rainfall. Heading into Sunday,
additional rounds of rainfall are expected as the frontal boundary
slowly sags south. There could be another round of severe storms
Sunday afternoon and evening across mainly northwest Wisconsin.
PWATs will continue to run in excess of 2" keeping the threat for
flooding in place. High pressure will then begin to build in on
Monday with showers ending from northwest to southeast through the
day. Dry conditions will then persist through the remainder of the
period as high pressure remains in control. Temperatures will be
near to slightly above normal for Monday before warming to 7-10
degrees above normal for Tuesday through Thursday. Dewpoints will be
in the 50s during this time, so it should be fairly comfortable with
any cooler temperatures being pinned along the immediate lakeshore.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 636 PM CDT Fri Jun 15 2018
VFR, but a lot of uncertainty heading through the night regarding
convection and where it treks. If anything, there should be an
uptick in activity Saturday morning which should bring about sub-
VFR conditions - played the TAFs that way though intentionally
left them vague as details can change rapidly.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 59 77 62 76 / 50 70 70 60
INL 60 75 58 73 / 40 50 50 30
BRD 66 80 66 78 / 60 60 80 70
HYR 67 84 68 84 / 50 60 70 60
ASX 59 74 61 77 / 60 60 70 60
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Flash Flood Watch through Sunday morning for WIZ001>004-006>009.
MN...Flash Flood Watch through Sunday morning for MNZ019-035>038.
LS...None.
&&
$$
UPDATE...Wolfe
SHORT TERM...JTS
LONG TERM...BJH
AVIATION...Wolfe
Area Forecast Discussion
National Weather Service Goodland KS
553 PM MDT Fri Jun 15 2018
.SHORT TERM...(This afternoon through Saturday)
Issued at 1129 AM MDT Fri Jun 15 2018
Latest upper air analysis shows southwest flow over the Plains.
Within the flow multiple smaller scale troughs were analyzed by
the RUC reanalysis. Towering cumulus clouds and light rainfall had
developed over Central and Southwestern Nebraska where a corridor
of strong isentropic lift had developed. These weak showers are
not expected to last into the afternoon due to the isentropic lift
weakening over the next hour or so. At the surface a low was
positioned near Limon, CO, with a trough axis extending from the
Limon area in an arc northward to near Benkelman, NE. A weak cold
front had moved into the northwest part of the forecast area,
which should provide some relief from the heat in Yuma County. The
dry line was bowing east into NW KS.
For the rest of the afternoon am not expecting any storms to form
until close to 5 PM MT when upper level lift strengthens over the
trough axis/dry line from roughly Gove to Leoti KS. If storms
develop they will be isolated at best. Meanwhile isolated to
scattered storms will move in from the west ahead of an upper
level short wave trough, crossing into western Kit Carson/Cheyenne
counties close to 6 PM MT.
This evening the upper level short wave trough will deepen over
the center of the forecast area as it moves east. Am expecting
storm coverage to increase through mid evening as a result. During
the latter half of the evening the short wave trough will begin
filling. This will cause the short wave trough to turn and move to
the northeast. Storm activity should be done around midnight if
not before.
During the evening, as the upper level short wave trough deepens,
it will be co-located with the nose of the LLJ. This added lift
will help increase storm activity. Close to midnight the nose of
the LLJ will shift into Central Nebraska, causing storms to
decline due to the loss of lift from the LLJ and the weakening
short wave trough.
The biggest threat for any storms this afternoon or early this
evening will be wind gusts up to 65 MPH due to the high cloud
bases. Deep layer shear is around 20 kts, while effective shear is
50-60 kts. While hail can`t be completely ruled out, confidence
is on the low side that hail up to quarter size will occur due to
the weak shear and hot temperatures. Even though the effective
shear is quite strong, the storm activity should be behind the dry
line which will limit how strong the storms become.
At the surface the pressure gradient will remain tight, causing
winds to be breezy and lows to be warmer than last night.
Saturday the surface low will be shifted further north than today,
closer to Denver as the upper level long wave trough deepens over
the Pacific Northwest. This northward shift will move the hotter
air mass further north, giving the forecast area a slight relief
from the heat compared to today.
.LONG TERM...(Saturday night through Friday)
Issued at 245 PM MDT Fri Jun 15 2018
Main forecast concerns will be chances of thunderstorms through the
period and the possibilities of severe thunderstorms and an
increasing chance of locally heavy rainfall. Satellite showing an
amplified pattern from the Pacific to along the east coast of North
America. This pattern has remained unchanged with trough over the
western portion of the North America and ridging over most of the
eastern portion.
Western trough is the process of deepening with more energy coming
in from western Canada. In the southwest flow aloft both satellite
and upper air analysis showing a connection to the subtropical
moisture connection over Mexico and the desert southwest. Also the
remnants of tropical storm Bud are in this flow. Also slow moving
frontal boundary has sagged into the northwest portion of the area.
Models were a little high on the jet segment nosing into the Desert
Southwest. The Ecmwf was starting out a little better than the Gfs
and Canadian.
Saturday night...Some model difference on how far east to take
thunderstorms. Steering flow is nearly from the south. Surface
trough remains to our west with nearby front to our north through
the night. Models keep main lift from mid level shortwave to the
west of our area. Jet axis/any jet lift also remains to our west.
Nam develops a cluster of storms directly to our south over
southeast Colorado and southwest and brings it north. That is the
most aggressive of any solution.
Other output does bring some thunderstorms into the western and
central portions of the area. That makes more sense given the
reasoning above. With a more amplified pattern would expect the
ridge to hold stronger and keep the main precipitation to our west.
So at this time am fine with the slight chance to chance pops in my
area during the night. However it is possible that this could be too
far east.
Sunday/Sunday night...Out of the first three days, this looks to be
the most active time period. Ridging to the east and trough to west
look to edge east a little. So mid level lift instability will also
be further east and over our area. Jet axis/right rear quadrant gets
close to or affects the western portion of the area late in the day.
This moves across the area during the night.
Also surface trough will edge further east with the front able to
sag into the northwest portion of the area by late in the afternoon.
Models are consistent and reasonable in developing thunderstorms in
the northwest portion of the area where the deepest lift and best
instability is at. Because of the mid level system moving through
and convection along and behind the front will help shove the front
through the area during the night.
Jet axis/right rear quadrant gets close to or affects the western
portion of the area late in the day. This moves across the area
during the night. So expect a good chance of thunderstorms across
the area late in the afternoon and especially during the night.
Considering the instability, veering of winds, and a boundary
parallel with the flow, would expect a decent chance of severe
weather during this time. However, what may be a more widespread
threat will be locally heavy rainfall that could cause flash
flooding. Precipitable water values... This is 2 to 2.5 standard
deviations above normal. Considering the PWs and flow parallel to
the front, would expect training of thunderstorms that will be
producing high rainfall rates. Will be ramping up these threats in
the HWO.
Monday...Main jet has moved to the east of the area. Surface ridging
and drier, cooler, and more stable post frontal air mass will settle
over the area. It will be much cooler from the previous three days
and dry. Like the cooler blend temperatures which will be near 10
degrees cooler than on Sunday.
Monday night through Friday... Beginning on Tuesday night the models
come into major disagreement on how to handle the western closed
low/troughing over the western half of North America. The 00z Ecmwf
tends to hold onto the troughiness/closed low over the west the
longest and the furthest west as well. The ensemble would tend to
support the 00z Ecmwf the best. Also considering how amplified
the pattern is, the slower and more amplified pattern looks the
more likely solution. The PMDEPD mentions that the Ecmwf/Gefs and
deterministic Ecmwf fit with this idea and have been the most
consistent. However, the 12z Ecmwf has trended more like the Gfs
and more north and east than before.
The WPC surface progs for this period show the region remaining in
the post frontal upslope region to the north of a stationary
boundary. The WPC depiction shows that front slowing lifting back
north on Thursday and Friday. The Gfs and Ecmwf also show the front
near or over the southern/central portion of the area by the end of
the period.
So from a general/pattern recognition standpoint, this pattern is
favorable for getting repeated episodes of locally heavy rainfall.
The surface and mid level depiction from the deterministic/ensemble
and WPC, this looking close to a Maddox type I flash flood setup.
Precipitable water values look to stay in the 1 to 1.5 inch range.
This is 1.5 to almost 2 standard deviations above normal. So heavy
rainfall will be the main threat. However, there will be also be
some severe weather during this time.
So based on model differences, inconsistencies, and in general the
models showing a wetter and cooler pattern, will be making no major
changes to the forecaster blend temperatures and pops.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 536 PM MDT Fri Jun 15 2018
VFR conditions are expected at GLD and MCK through the 00Z TAF
period. There will a period of isolated thunderstorms moving
through the vicinity of GLD between 02-05Z and MCK between 03-06Z
followed by a period of LLWS overnight that will diminish around
14Z as the low level inversion diminishes and gusty south winds
begin mixing to the surface.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JTL
LONG TERM...BULLER
AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Lincoln IL
850 PM CDT Fri Jun 15 2018
.UPDATE...
Issued at 850 PM CDT Fri Jun 15 2018
Mostly clear skies can be expected tonight as high pressure aloft
brings subsidence to the area. A very warm air mass characterized
by near 20 degrees C air at 700 mb has arrived in the area and
will remain the next few days. Current dewpoints are in the mid
70s and will limit low temperatures to the low 70s overnight for a
very warm night. Current forecast is on track with these features
and no significant updates are needed this evening.
&&
.SHORT TERM...(This evening through Saturday)
ISSUED AT 317 PM CDT Fri Jun 15 2018
20z/3pm visible satellite imagery shows just a few patches of
diurnal Cu across central Illinois this afternoon...as convective
temperatures have not quite been achieved and a strengthening
mid-level cap has prevented thunderstorm development. The closest
convection has fired well to the south across southeast Missouri
into western Kentucky where the cap is weaker. Latest run of the
HRRR now keeps all isolated convection south of the KILX CWA late
this afternoon into the early evening, so have gone with a dry
forecast. Will be a warm and muggy night with overnight low
temperatures remaining in the 70s. Abundant sunshine and light
southwesterly winds will boost high temperatures into the lower
to middle 90s on Saturday. With dewpoints hovering in the lower
to middle 70s, heat index readings will peak from 100-105. Have
therefore expanded the Heat Advisory to cover the entire CWA.
.LONG TERM...(Saturday night through Friday)
ISSUED AT 317 PM CDT Fri Jun 15 2018
Heat and humidity will continue both Sunday and Monday, with air
temperatures in the middle 90s and peak heat index readings
around 105 both days. The next chance for widespread convection
will hold off until Monday night when a short-wave trough
traversing southern Canada will begin to flatten the prevailing
upper ridge and push a cold front southward into Illinois. Models
are in fairly good agreement with the front arriving across the
northern CWA Monday night, then sinking slowly southward into
south-central Illinois during the day Tuesday. With ample deep-
layer moisture in place, think showers and thunderstorms will be a
good bet...particularly Tuesday and Tuesday night.
After that, there is still some uncertainty as to how far south
the front will drop before becoming parallel to the upper flow and
stalling. The 12z ECMWF tends to hold the front slightly further
north than the GFS, which could potentially keep rain chances
alive across the southern CWA through Thursday. For now, will
stick with the GFS...which maintains rain chances across the far
south through Wednesday, then features dry/cooler weather for
Thursday and Friday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 629 PM CDT Fri Jun 15 2018
VFR conditions expected for the next 24 hours across the central
IL terminals. Cloud cover minimal with mainly just some low
coverage of afternoon and evening cumulus around 5000-6000 ft
AGL. Winds generally south 5-12 kts.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory until 7 PM CDT Monday for ILZ027>031-036>038-
040>057-061>063-066>068-071>073.
&&
$$
UPDATE...37
SHORT TERM...Barnes
LONG TERM...Barnes
AVIATION...37
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
644 PM CDT Fri Jun 15 2018
.SHORT TERM...(This evening through Saturday)
Issued at 336 PM CDT Fri Jun 15 2018
The primary forecast concerns through Saturday are temperatures and
thunderstorm/severe potential. The large upper ridge over the
Eastern U.S. keeps temps summer-like for Nebraska, while a stalled
surface boundary will be the focus for convection.
This evening and tonight... A lee side surface low associated with
the front deepens across eastern CO while southeast winds/upslope
flow lead to increased forcing and lift. Broad isentropic upglide
with the front is underway, most notable around 315K. Convective-
allowing guidance has varying degrees of activity developing in the
panhandle and spreading northeast with this feature. The HRRR and
HREF are the wettest, while the RAP and NAM-nest are more subdued.
Went with a general blend approach, considering a ripe environment
(ample instability of 3000+ j/kg MUCAPE from mesoanalysis and good
moisture of 60s dew points), but a very warm layer around H7 (temps
near 16C) are keeping things in check. As a strong LLJ develops
tonight, the added convergence and shear should help fire off or
maintain current convection. However, deep-layer shear remains
limited (especially south of the front), so not expecting a
widespread event. Temperature-wise, kept lows very mild in the 60s
and even lower 70s central Neb due to aforementioned LLJ and H85
temps holding steady around 25C.
Saturday... The low drifts northeast to the CO/KS/NE area while the
front remains draped across the Sandhills. Looking at another hot
and relatively humid day across SW and north central Neb with highs
in the mid 90s, while far NW Neb stays in the lower 80s. A minimum
in instability and layer of dry air in the mid levels should bring a
lull in activity during the morning and early afternoon. Conditions
ripen once again mid/late afternoon with convection initiating
along/north of the front. Shear increases with strengthening H5 flow
and the beginning of a coupled jet. Any storm that develops will
likely quickly become strong or severe with large hail.
.LONG TERM...(Saturday night through Friday)
Issued at 336 PM CDT Fri Jun 15 2018
The latest model blend has marked up the 7-day storm total rainfall
to 1 to 4 inches with highest totals across the eastern Panhandle.
Precipitable water rises to 1.5 to 1.8 inches in the NAM, SREF, GFS
and GEM models Saturday night and remains at those levels until
Monday morning. Thereafter, the models show cold air aloft (-8C to -
9C ) at 500mb destabilizing the atmosphere daily in a post-frontal
environment. This should support a chance of showers and
thunderstorms Monday through Friday. Likely POPs are in place
Saturday night through Sunday night with the potential for severe
weather and locally heavy rainfall.
The frontal boundary across swrn and ncntl Nebraska this afternoon
lifts north into the Sandhills Saturday afternoon. This will be the
focus for thunderstorms Saturday night. SPC outlooked areas along
and north of the front for severe weather potential (Springview-
Mullen-Sidney). Large hail and wind damage are the hazards with an
isolated tornado threat. The initial hail/isolated tornado threat
should evolve into lines and segments capable of wind damage.
Following the WPC excessive rainfall guidance, the forecast includes
a mention of heavy rainfall in the outlooked areas; Sheridan county
Saturday night and most of wrn and ncntl Nebraska Sunday afternoon
and Sunday night. The combination of an upper level low across the
wrn U.S., a stalled surface front, a nocturnal low level jet and
moisture from former hurricane "Bud" will be operating to produce
locally heavy rainfall. Later forecasts may expand the areas for
locally heavy rainfall as the NAM and GFS would suggest a threat as
far south as Interstate 80 Saturday night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 641 PM CDT Fri Jun 15 2018
Thunderstorms will move into the Nebraska Panhandle and southwest
Nebraska late this evening with increasing clouds. Storms are
expected to move through KVTN and KLBF between 6 and 7z. Clearing
skies through the morning on Saturday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...Snively
LONG TERM...CDC
AVIATION...Power
Area Forecast Discussion
National Weather Service Louisville KY
704 PM EDT Fri Jun 15 2018
...Updated Aviation Discussion...
.Short Term...(This evening through Saturday)
Issued at 300 PM EDT Fri Jun 15 2018
Mainly clear skies were observed across central Kentucky and
southern Indiana this afternoon. A scattered cu field has developed
over the SW counties (BG/Russellville). There`s still a substantial
dewpoint gradient across the area, with around 60 in the Bluegrass
and the low to mid 70s in the southwest. More widespread cu
development has occurred in the moist atmosphere to our west and
southwest. And with a remnant shortwave trough dropping through,
scattered storms have popped up over western KY. This activity is
expected to remain west of Bowling Green for the most part, but the
HRRR suggests a couple storms could sneak into the SW forecast area.
Tonight will be mainly clear with patchy light fog possible in the
moist air in south-central Kentucky. We`ll see upper ridging
continue to build over the weekend, and Saturday does look a bit
hotter and slightly more humid than today. Peak heat indices are
forecast to top out at 95-100 degrees along and west of I-65, where
dewpoints will be highest.
.Long Term...(Saturday night through Friday)
Issued at 230 PM EDT Fri Jun 15 2018
...Hot and Humid...
Upper ridging is still on track for the weekend and into Monday,
resulting in hot and humid conditions for the Ohio Valley. Sunday
and Monday will be particularly unpleasant as dew points rise into
the lower 70s and we see peak afternoon heat index readings in the
mid 90s to around 100, especially west of I-65.
While a stray storm or two is possible Sun/Mon, most areas will be
dry under the upper ridge. The better chance for storms will come
Tue-Wed as a boundary sinks south through the region. Depending on
how much the ridge breaks down and how far south that boundary
moves, south central KY may see continued precip chances through
late week. Highs should drop back into the mid to upper 80s for
the second half of the week.
&&
.Aviation...(00Z TAF Issuance)
Issued at 703 PM EDT Fri Jun 15 2018
Some very patchy fog may develop early tomorrow morning near
KHNB/KBWG and could briefly reduce visibilities. Otherwise, VFR
conditions are expected through the period as shower and storm
activity remain north and west of the region.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Short Term...EBW
Long Term...AMS
Aviation...DM
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
959 PM CDT Fri Jun 15 2018
.DISCUSSION...See updated information for land areas below.
&&
.UPDATE...Local radar trends have shown a general decrease in
coverage going into the evening, but expect re-development and an
increased coverage during the pre-dawn hours. With little
movement of the the weak mid-level trof axis (shear zone) aligned
over the deep south and plentiful deep layer moisture, forecasters
have opted to make no change to the ongoing forecast with regard
to probabilities of showers and storms. Some of the latest high
resolution weather model guidance, notably the latest HRRR and 3KM
NAM, suggests storms could become numerous along the Gulf coast
and near shore waters late in the night. /10
&&
.PREV DISCUSSION... /issued 638 PM CDT Fri Jun 15 2018/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...VFR conditions will prevail through much of the
forecast for all TAF sites, but pilots may need to navigate around
thunderstorms enroute through mid evening around the Mobile metro
area. The shower and thunderstorm activity is expected to increase
late tonight across the western Florida panhandle, so added TS to
PNS starting at 05z, and added a TEMPO group from 06z to 10z for
occasional periods of mid range MVFR ceilings and visibilities due
to thunderstorms. Shower and thunderstorm activity is expected to
increase again Saturday afternoon along the entire north central
gulf coast region, so added a PROB30 group from 18z to 24z for all
TAF sites for now. Will monitor the evening activity and update
as needed. /22
PREV DISCUSSION... /issued 352 PM CDT Fri Jun 15 2018/
NEAR TERM /Now Through Saturday/...A weak mid level circulation
continues to spin in the vicinity of southwest AL this afternoon,
while an associated weak mid level trough axis extends across much
of our region. A very moist airmass remains in place across our
forecast area under this feature this afternoon, with precipitable
water values estimated between 2" and 2.2" across the region. The
earlier convection near the coast has diminished as of 3 PM, but new
convective development is occurring over portions of southeast MS
and interior southwest AL where more sun has allowed for
destabilization on the northwestern periphery of the mid level
circulation. This convection will be need to be monitored closely as
it moves into Choctaw, Clarke, Wilcox and potentially Washington
counties this afternoon, as this portion of the region has received
heavy rainfall amounts on the order of 2" to 5" since Thursday
morning. Additional heavy rainfall could result in at least minor
flooding of low lying areas, but if heavier rainfall rates
materialize with some of these stronger storms, we cannot entirely
rule out very localized flash flooding.
Convection over the interior may tend to move/develop southwestward
into portions of southeast MS and farther south over southwest and
south central AL this evening per HRRR and WRF-ARW trends. This
activity may weaken with loss of daytime heating, with a potential
lull in convection during the mid to late evening hours. The weak
mid level circulation may become less discernible with time late
tonight into Saturday, but the associated plume of deep moisture
will continue to extend across our forecast area through Saturday
afternoon. Additional scattered to numerous showers and
thunderstorms may re-develop overnight into early Saturday morning,
particularly near coastal portions of the western FL panhandle and
southwest AL, while other isolated to scattered showers and storms
remain possible farther inland. We have trended the forecast close
in line with guidance from WPC, WRF-ARW and HRRR, which favors
higher QPF and POPs near the southwest AL and western FL coast (50-
60% coverage) between 06-12z, with values tapering farther inland.
Scattered to numerous showers and storms should develop inland with
time Saturday morning into afternoon. Plentiful deep moisture will
support a continued potential for locally heavy rainfall through
Saturday afternoon. Considering the heavy rains that have fallen
over a good portion of the area the past 24-48 hours, will keep a
limited potential of flooding highlighted in graphics and the HWO
through Saturday. No significant changes to temperatures were made.
/21
SHORT TERM /Saturday night Through Monday night/...With the mid-
level disturbance exiting off to the northeast, we return to a
more typical summerlike pattern through the short term in terms of
shower and thunderstorm coverage. Expect chance PoPs (30-40%) and
scattered activity to develop both Sunday and Monday, primarily
during afternoon hours as it will be largely driven by daytime
heating. Localized heavy rainfall and frequent lightning will
remain the primary threats, though stronger storms will be capable
of producing gusty winds and perhaps some small hail as well. High
temps reach the upper 80s to around 90 each afternoon and lows
remain in the low to mid 70s each night. /49
LONG TERM /Tuesday Through Friday/...The weather pattern remains
unsettled through next week as weak low pressure in the upper
levels persists over the northern Gulf coast region. The
combination of daytime heating and lingering deep-layer moisture
(PWATs at or above 1.75 inches) should support scattered
convection each afternoon and evening, with activity tapering off
each night. Thus, have opted to maintain our diurnal pattern of
chance/slight chance PoPs each day/night, respectively, throughout
next week. Temperatures to remain near seasonal, with highs in
the upper 80s to lower 90s and lows in the lower to mid 70s. /49
MARINE...Area marine observations indicate a light westerly flow
pattern prevalent this afternoon away from earlier outflow
boundaries. A light to occasionally moderate southwesterly to
southerly flow should develop tonight into Saturday as surface
ridging shifts over the eastern Seaboard and FL peninsula. Light
southeasterly flow then looks to return Sunday into early next week
as ridging builds westward over the north central Gulf and Gulf
Coast states. /21
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion
National Weather Service Marquette MI
750 PM EDT Fri Jun 15 2018
.SHORT TERM...(This evening through Saturday)
Issued at 447 PM EDT FRI JUN 15 2018
WV imagery and RAP analysis indicated a mid/upper level trough over
the wrn CONUS and a ridge from the lower MS valley to the wrn Great
Lakes resulting in sw flow from the plains to wrn Lake Superior. At
the surface, a trough extended from ne Manitoba into wrn MN with a
warm front from w cntrl MN to sw WI. The 1000-850mb theta-e ridge
through the upper MS valley along with with 25-35 knot 850 mb winds
provided plenty of instability with MUCAPE values to 3k J/Kg to
support clusters of shra/tsra near the top of the ridge from nw WI
around KIWD. The heaviest rain earlier today also remained near far
wrn Upper Michigan where rainfall reports/estimates were in the 2-4
inch range. The brief bout of strong sse winds behind the initial
area of convection due to a wake low/gravity wave have also
diminished.
Tonight, into this evening, expect that the shra/tsra will remain
continue to slide ese from nw WI given the alignment of the low
level jet inflow and position of the CAPE gradient. By the
overnight, there is more uncertainty as additional tsra development
is likely over nrn MN to wrn Lake Superior as a shortwave trough
moving out of the Dakotas approaches the region and the low level
jet strengthens. Confidence in the location of tsra development and
eventual path is still low but most short-range model guidance
suggests that wrn Upper Michigan will again see the greater tsra
chances. With very high PWAT values in the 1.5-2.0 inch range
remaining over the region, the main hazard will again be heavy rain
with the potential for some small hail and higher wind gusts with
the strongest tsra clusters. A Flash Flood Watch was issued for the
far west where the ground is already saturated and stream levels are
high and where the threat of additional heavy rainfall is also
significant.
Saturday, confidence in any details with convection development
remains below average as the impacts of convection earlier in day
(the amount of cloud cover/instability and outflow boundaries) will
have a significant influence on later evolution. Shra/tsra chances
will linger through the entire day even though most of the day may
not see any pcpn. High temps may also be reduced by leftover
clouds/pcpn. Nevertheless, very warm and humid conditions are
expected with highs to the lower 80s and dewpoints into the upper
60s.
.LONG TERM...(Saturday night through Friday)
Issued at 457 PM EDT FRI JUN 15 2018
Models suggest that a slowly progressive northern stream pattern
will prevail into next week. This will leave Upper Michigan on the
periphery of the mid/upper level srn stream ridge through the
weekend until a shortwave trough moving through nrn Ontario helps
push the sfc frontal boundary to the south. Mainly nw flow will
then prevail through the rest of the week as a trough develops over
ern Canada.
Saturday night through Sunday night, the potential for additional
rounds of more widespread shra/tsra is expected as the sfc boundary
sags into the region, especially later Sunday into Sunday night. One
or more shortwaves or sfc waves may also enhance the possibility for
heavy rain as high PWATS remain over the region.
Monday, the frontal boundary is expected to sag to the south of
Upper Michigan, taking the higher shra/tsra chances with it as rain
should diminish from north to south. Clouds and lingering rain will
limit high temps to the 60s to lower 70s.
Tue-Fri, drier air will move back into the region as sfc high pres
builds in from the plains and s cntrl Canada dropping dewpoints back
into the 40s. Temps will remain near or slightly above normal. There
may be a chance for some lighter showers with any weak clipper
shrtwvs that brush the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 749 PM EDT FRI JUN 15 2018
Upslope southerly winds in the wake of earlier pcpn may support ocnl
low MVFR cigs at KSAW this evening. In addition, recent development
of upslope easterly winds at KCMX could lead to IFR cigs at times,
but confidence is low for that to occur. Otherwise, VFR conditions
should generally prevail at KIWD/KCMX/KSAW thru this fcst period.
However, clusters of shra/tsra will be roaming the Upper Lakes
region and may impact the terminals at times thru Sat. Confidence in
location and timing of these shra/tsra are low, but it appears late
tonight and Sat morning may be a time period where the terminals may
be impacted. If so, MVFR/IFR conditions will be possible.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 458 PM EDT FRI JUN 15 2018
Winds will generally remain between 10 to 20 knots through the
end of the weekend. However, additional areas of showers and
thunderstorms through Sunday night may result in some very gusty
erratic winds, maybe even as high as 35 knots for a brief period.
Winds will relax into early next week with speeds generally around
or less than 15 knots, with perhaps a brief uptick towards 20
knots on Monday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Flash Flood Watch through Saturday morning for MIZ002-009.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...JLB
AVIATION...Rolfson
MARINE...JLB
Area Forecast Discussion
National Weather Service Paducah KY
444 PM CDT Fri Jun 15 2018
.UPDATE...
Issued at 441 PM CDT Fri Jun 15 2018
Updated Aviation discussion for 00Z TAF Issuance.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 241 PM CDT Fri Jun 15 2018
Main forecast story in the short term continues to lie with the
building heat as we head into and through the weekend. Large
scale mid/upper level ridge will align itself along much of the MS
and lower OH River Valleys during most of the short term. Surface
dew points in the 70-75 range will combine with afternoon temps
into the lower/mid 90s to produce heat index values from 100 to
105 or so, esp much of se MO/srn IL and far wrn KY. Beginning with
yesterday (Thu), this could make 4 straight days of 100-105 heat
indices in much of the that area. Therefore, will go ahead and
issue a heat advisory for Sat/Sun with this forecast package for
the aformentioned regions.
Areas outside of the heat advisory, such as sw IN and much of the
Pennyrile of wrn KY are expected to stay closer to 100 degree
heat indices, so plan to cover those regions with a special
weather statement for now. The hottest afternoon could end up
being Sunday, so an expansion of the heat advisory a bit farther
east may be needed with time.
As far as precip chances are concerned, it appears that a weakness
in the pronounced mid level pressure ridge will sick around
over/near wrn KY most of the weekend. A modest moisture swath
associated with this feature may be enough to trigger more in the
way of isolated thunderstorms both Saturday and Sunday during
peak heating hours. Though most locations should stay rainfree and
hot this weekend, will need to monitor any storms that do form
for gusty winds and small hail due to the extreme instabilities
expected. Outflow boundary interaction(s) would then be the main
focus for any additional storm development.
.LONG TERM...(Monday through Friday)
Issued at 241 PM CDT Fri Jun 15 2018
Guidance continues to hint that the upper level ridge will break
down and push off to our southeast next week. This should allow a
cold front to progress southward into the region at some point.
Right now the timing looks to be mainly Tuesday night into
Wednesday, with PoPs increasing ahead of it on Tuesday, especially
in the north.
Given the upper level pattern, it will be hard to rule
out precipitation chances for at least some portion of the area
during most periods in the extended. An increase in mid level flow
expected by mid to late week, may help to enhance the overall
coverage of showers and thunderstorms. The 12z ECMWF hints at this,
while the GFS actually brings down surface high pressure from the
north which would dry out much of the area for Thursday and Friday.
Thus lower confidence later in the extended period.
Some additional cloud cover combined with 500 mb heights lowering,
should allow temperatures to lower somewhat next week. However,
above normal readings look to continue, with highs generally close
to 90 degrees through the week. With dewpoints remaining in the
lower 70s much of the period, heat index values are expected to peak
in the mid 90s to around 100 most days.
&&
.AVIATION...
Issued at 441 PM CDT Fri Jun 15 2018
Latest HRRR keeps pm convection active near our southern terminals
(KCGI/KPAH) til 03Z, then diminishes all activity afterward.
Excepting vicinity or categorical mentions there til then, should
otherwise return to VFR/clearing skies with another late night
potential for MVFR fog (all terminals) toward daybreak. Diurnal cu
tmrw should genesis in the 4-5K FT AGL range.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory from 11 AM Saturday to 7 PM CDT Sunday for
ILZ075>078-080>094.
MO...Heat Advisory from 11 AM Saturday to 7 PM CDT Sunday for MOZ076-
086-087-108>112-114.
IN...None.
KY...Heat Advisory from 11 AM Saturday to 7 PM CDT Sunday for
KYZ001>011.
&&
$$
Area Forecast Discussion
National Weather Service Tucson AZ
855 PM MST Fri Jun 15 2018
.SYNOPSIS...Widespread rain with a few embedded thunderstorms will
continue as remnants of Bud pass nearby tonight and early Saturday.
Expect cooler temperatures again Saturday followed by dry conditions
Sunday and the return of June heat early next week.
&&
.DISCUSSION...Widespread rain with a few embedded thunderstorms will
continue overnight into early Saturday. Latest models keep the focus
on areas south and east of Tucson for picking up the most rainfall
through Saturday morning. Latest HRRR solution showed most of the
rain shifting farther eastward by 13Z Saturday. This will result in
a brief lull before showers and thunderstorms redevelop with the
daytime heating. The current forecast appeared to handle this trend
well, so no updates necessary late this evening. Refer to the
additional sections for more details.
&&
.AVIATION...Valid through 17/06Z.
Scattered showers and a few embedded thunderstorms will continue
through the period. Clouds BKN-OVC at 10-15k ft AGL with lower
decks to 5-8k ft AGL near showers through Saturday. SFC winds
generally WLY/NWLY at 12-15 kts, with gusts to 35 kts possible near
any -TSRA. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Showers and a few thunderstorms will continue
through tonight and early Saturday. The heaviest rainfall amounts
are likely east and south of Tucson. Recent burn scars could
experience increased runoff possibly leading to some flooding,
particularly the Frye and Lizard fire burn scars. Conditions
gradually improve from west to east throughout the day on Saturday,
followed by dry conditions Sunday and a warming trend next week.
&&
.CLIMATE...The 6th longest dry streak on record for Tucson came
to an end today with the first measurable rain at the airport since
February 28th. Even though the summer thunderstorm season begins
today, most area rainfall records for June 15th are quite low, so
expect lots of record rainfall reports today and Saturday. Some
areas may also be close to setting low high temperatures and warm
minimums for June 15th.
&&
.PREV DISCUSSION...On Saturday, a brief period of clearing behind
Bud will allow for better solar insolation compared to today. The
upper low west of San Diego will move into southwest Arizona
Saturday afternoon, with stronger upper level dynamics working on
residual moisture to create another round of scattered showers and
thunderstorms. Localized heavy rain and strong to severe storms are
possible as cooler air aloft pushes across the area on southwesterly
flow. The precipitation threat will then end from west to east late
Saturday evening into early Sunday morning.
With the aforementioned upper low ejecting northeastward into New
Mexico on Sunday, noticeably drier air will settle in across the
region. This transition will be complete with clear to mostly clear
skies and the return of near triple digit heat by Monday.
Dry conditions and a warming trend will continue through Friday of
next week as the Four Corners high typical of our monsoon struggles
to set up, and instead tries to consolidate west of our area keeping
moisture to the east.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
PREV DISCUSSION/AVIATION/FIRE WEATHER...ECC/JP
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