Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/11/18
Area Forecast Discussion
National Weather Service Bismarck ND
856 PM CDT Tue Jul 10 2018
.UPDATE...
Issued at 855 PM CDT Tue Jul 10 2018
Severe thunderstorm watch issued by Storm Prediction Center includes
11 counties in northwest and north central North Dakota...including
Crosby, Williston, Watford City...east to Bottineau/Minot/Rugby.
Increased chances of thunderstorms tonight, keeping the best chances
across the northwest and north central. The northern portion of the
line of Montana storms have maintained themselves both in strength
and in a more continuous line...and continuing to push east towards
the northwestern border of North Dakota. The storms in the southern
portion of the Montana line have become more isolated and not as
strong.
The HRRR high res model keeps the line of storms more or less intact
as it moves east across North Dakota, while the Experimental HRRR
keeps only the northern portion intact as it progresses eastward
across northern North Dakota. Thus have highest chances of
thunderstorms across the north (where the severe thunderstorm watch
is in effect) and lower chances across southwest and south central
ND.
UPDATE Issued at 630 PM CDT Tue Jul 10 2018
Some rather weak convection with mostly showers but some
thundershowers developed this afternoon across northwest ND, and
have moved east into north central ND. Expect this isolated
convection to continue east. Attention turns to our north in
Saskatchewan, where this convection appears linked to the north
central ND convection, likely associated with upper level impulses
riding the h500 ridge - the Canadian convection a bit stronger as
the mid-level thermal capping is stronger across North Dakota. This
convection should also continue eastward/northeastward.
Main attention is focused over southwestern Saskatchewan and central
Montana, where a line of strong to severe storms had developed
during the mid-afternoon hours. These storms are associated with a
set of upper level impulses out ahead of an upper level low pressure
system moving east across Alberta into Saskatchewan tonight. Models
show the stronger impulses lifting northeast into Saskatchewan and
Manitoba tonight, clipping northwest into north central North
Dakota. Latest iterations of short term high res models would
suggest this line of storms arriving at the western border of ND
around 9 pm CDT/8 pm MDT. Some of these models show some convection
perhaps holding together farther south (going into southwestern ND
as well) while others maintain a more northern boundary to the
convection in northwestern ND.
Later updates should address these trends.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 322 PM CDT Tue Jul 10 2018
Severe thunderstorm potential northwest North Dakota headlines the
short term highlight.
Latest water vapor imagery indicates shows our next 500mb/700mb
shortwave trough now located over the chimney stack of Idaho.
Associated surface cold front stretching from western Montana
south into eastern Idaho. Both features will propagate east this
afternoon and evening, reaching western North Dakota by around
sunset, and continuing to move across central ND overnight/through
early Wednesday morning. Height falls indicated per model data
and SPC mesoanalysis are underway across the west, and will fall
more noticeably this evening. Latest Convective Allowing Models
fairly consistent with a line of severe thunderstorms stretching
from western Saskatchewan into Divide and portions of northern
Divide counties by around 03z-04z/10PM-11PM CDT Tuesday. They will
continue to sweep east into Burke and along the northern border
through 08z, weakening as they move farther east. There could be
isolated showers/thunderstorms along the front farther to the
south, but overall, much weaker instability and shear should
inhibit any threat of widespread severe weather. The cold front
will be through the James River Valley by 18z-00z Wednesday.
Lingering showers and some thunderstorms through south central
North Dakota in the morning, then drier air/less humid air will
sweep from west to east in the afternoon. Dewpoints will be in the
50s west and central, with lower 70s lingering across the
southern James River Valley. A marginal risk for severe weather
continues across the southern James River Valley Wednesday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 322 PM CDT Tue Jul 10 2018
Weak cyclonic flow transitions to broad anticyclonic Thursday
through Saturday afternoon with mainly a dry forecast. The one
exception would be Wednesday night across far southern North
Dakota where some shower activity from South Dakota may shift into
our far southern counties. Other than that, the next potential
severe weather threat looks to come Saturday afternoon through
Saturday night as a strong cold front sweeps from northwest to
southeast associated with a southern Canadian upper low. Behind it
Sunday and through Tuesday, expect much cooler and drier air with
highs in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 630 PM CDT Tue Jul 10 2018
Threat for thunderstorms highest at KISN/KMOT from 03z through 08z
Wednesday. Still some uncertainty if the TAF sites will have a
direct impact at this time, but have introduced a tempo group at
KISN since storms forecast to reach there around 03z. For now, will
maintain a VCTS at KMOT. If something does develop, wind gusts to
65kt and hail to one inch diameter would be the main threats. Rest
of the terminals should have a minimal threat at best and will keep
any mention of precipitation out of the forecast for now. Vfr
cigs/vsbys for now.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...KS
LONG TERM...KS
AVIATION...JV
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
619 PM CDT Tue Jul 10 2018
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Late afternoon sea breeze convection is pushing west
of MFE, which will leave more settled conditions for the rest of
tonight. Mid level moisture will trend lower the next 24 hours,
with surface high pressure and mid level ridging supporting a more
stable atmosphere. Look for light to moderate southeast winds
through Wednesday, with a mix of clouds and sun. Low clouds will
tend to be scattered to broken from mid to late Tuesday morning,
and more scattered the rest of the day, with a few high clouds.
Rain chances Wednesday will be more muted compared to today. All
in all, conditions will be mainly VFR.
&&
.PREV DISCUSSION... /issued 248 PM CDT Tue Jul 10 2018/
SHORT TERM (Now through Wednesday Night): Showers have really
struggled to develop today, despite the slug of deeper column
moisture (PW of 1.9-2.0") working into the eastern half of the CWA
from the Gulf. Forcing is lacking on this (anticyclonic) side of
modest 30-40 KT upper-level jet and low-level subsidence is
indicated by RAP BUFKIT soundings.
Ill-defined surface pressure/height aloft fields are progged to
persist through the short-term. An H25 low, embedded within the mean
TUTT, will progress further inland into Mexico tonight, taking the
aforementioned jet with it. This leaves weak upper-tropospheric
ridging in place. Consequently, mid-levels dry considerably on
Wednesday, with PW falling below 1.5" on Wednesday night. So, after
this afternoon, no mentionable precip chances in the forecast.
Some high clouds will move in overnight tonight, with lows generally
in the mid-70s F. It`s not really the season, but think we`ll see
some patchy fog develop across Jim Hogg/Brooks/Kenedy counties late
tonight/early Wednesday morning. Surface winds go nearly calm and
RH`s approach 100%. With a drier atmospheric column on Wednesday,
H85 temps edge up 1-2 deg C from today. Daytime highs will also
nudge up to right around or perhaps a degree or two above climo,
with 100-degree readings possible for the Upper Valley. Lows
Wednesday night once again expected to be mainly in the mid-70s.
LONG TERM (Thursday through Tuesday): High pressure building into
the Gulf of Mexico works eastward into the weekend as a mid
level inverted trough of low pressure arrives into Deep South
Texas, eventually moving into Northeast Mexico early next week.
Moisture remains rather limited with drier air aloft by Sunday.
Will keep isolated seabreeze convection previously advertised for
Friday, with slightly better chances Saturday, and lean dry
through the rest of the period.
Temperatures remain near to slightly above normal, with typical
summertime triple digits in the upper valley and points northwest.
Breezy south-southeasterly winds during the afternoon hours on
Sunday and Monday could help boost high temperatures a degree or
two. Heat Index values will top off near 104F to 107F for most
locations in the valley each afternoon.
MARINE (Now through Wednesday Night): Benign boating conditions
should continue through the short-term, with light-to-moderate SE
winds peaking at 10-15 knots on the Laguna Madre Wednesday
afternoon. Gulf seas remain slight with no incoming swells noted.
Only very isolated showers may occur through Wednesday morning.
Thursday through Sunday Night: Light to moderate southeast winds
will continue into the weekend with high pressure gradually
shifting east across the Gulf of Mexico. Seas of generally 2 to 3
feet are expected through Saturday. Moderate to breezy
southeasterly winds Sunday afternoon into Sunday night will result
in choppy bay conditions and 2 to 4 foot wind-driven waves across
mainly nearshore Gulf waters. Isolated showers and thunderstorms
are possible Friday and Saturday.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
54/63/62
Area Forecast Discussion
National Weather Service Caribou ME
950 PM EDT Tue Jul 10 2018
.SYNOPSIS...
A cold front will exit the Downeast coast early tonight.
High pressure will build across the region Wednesday into
Thursday. The high will begin to move east of the region Friday
and a weak cold front will move into the area Saturday.
&&
.NEAR TERM /THROUGH WEDNESDAY/...
940 PM Update: Just about all shwrs have ended across the FA,
with no mention in the fcst xcpt alg the downeast coast in
deference to recent HRRR model runs which show an additional
batch of shwrs later tngt msly tracking W to E offshore ovr our
coastal waters. Otherwise, adjustments were made to fcst hrly
cld cvr, temps, dwpts, and winds from latest sat imagery and sfc
ob trends. We utilized the CanGem model to better match the
faster obsvd fall of sfc dwpts behind the front across the Rgn
into the late ngt. No sig chgs to fcst ovrngt lows posted at 5
am this fcst update.
Orgnl Disc: A cold front will exit the Downeast coast early
tonight. Showers/thunderstorms will occur across mostly Downeast
areas early tonight in advance of the cold front. Gusty winds
and hail could accompany the stronger thunderstorms. The front
will slow while crossing the Gulf of Maine overnight, which will
keep a chance of showers across the Gulf of Maine and near the
Downeast coast into the early morning hours. Skies will then
remain partly cloudy Downeast overnight. High pressure will
build across the region overnight. Mostly clear skies are
expected across northern areas overnight with building high
pressure. High pressure will then bring mostly sunny skies to
the entire region Wednesday. Low temperatures tonight will range
from the mid to upper 40s north, to the mid to upper 50s
Downeast. High temperatures Wednesday will range from the mid
70s north, to the upper 70s to around 80 interior Downeast with
mid to upper 70s along the Downeast coast.
&&
.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
As stated by the midnight crew, a nice stretch of mid summer
weather for this term.
High pres at the surface is forecast to build into the region
w/Hrcn Chris expected to move well e of the region into
Friday. This system is expected to become extra-tropical as it
hits the colder temperatures. The biggest concern w/the tropical
system will be large swells that are expected to impact the
coastal waters by Thursday. This will be referenced more in the
Marine section below.
So, it looks like dry wx through the period w/seasonal
temperatures mainly in the upper 70s and lower 80s for the most
part. In the upper levels, a series of disturbances will move
across the region bringing clouds during the day. The ECMWF
wants to bring some light rain showers while the NAM and GFS
stay dry as does for the most part, the GFS Ensemble. The
Canadian Global keeps it dry as well. So, the decision was to
stay w/a dry forecast. The upper trof is shown to cutoff as it
move over the coastal waters on Friday w/the high pres over the
Ohio Valley nosing in from the Ohio Valley.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The upper ridge axis is expected to weaken Friday night as the
next cold front apchs from Canada. Clouds will be on the
increase Friday night w/the threat for some showers later Friday
night, mainly across the w and nw areas. Thunder is a
possibility but instability parameters look weak and given the
low confidence, decided to keep the mention of thunder out of
the forecast for now.
Saturday is forecast to be a warmer and more humid day
w/showers and tstms expected to break out ahead of the front.
Given the timing of the precip by mid afternoon and heating,
confidence is high enough to include tstms Saturday into
Saturday evening. There should be enough instability to allow
for storms to develop. The front looks like it either washes out
or breaks apart w/showers ending by midnight. The upper trof is
expected to move across the region by Sunday w/some left over
showers. High pres looks like it will ridge across the region
by Monday. Temperatures and humidity levels are expected to
increase over the weekend into early next week.
&&
.AVIATION /23Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: Variable conditions will occur with any
showers/thunderstorms, mostly Downeast, early tonight. Stronger
thunderstorms could produce gusty winds and hail. Otherwise, VFR
conditions are expected across the region tonight through
Wednesday.
SHORT TERM: VFR conditions expected into Fri. A cold front
crossing the region on Saturday could bring a period of MVFR
conditions w/showers and possible tstms. VFR conditions are
expected Sunday.
&&
.MARINE...
NEAR TERM: Winds/seas will remain below small craft advisory
levels tonight through Wednesday. Showers/thunderstorms are
expected through early tonight, with isolated showers late.
Visibilities could also be reduced in patchy fog tonight through
early Wednesday.
SHORT TERM: The swell from Hrcn Chris is expected to build later
Wednesday into Thursday. The long periods of 14-16 seconds with
seas building to 5 ft or so will lead hazardous seas. Given the
latest forecast track of Hrcn Chris, confidence is low on
prospects for High Surf Advisory. There is still some time to
assess this potential.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...VJN
Short Term...Hewitt
Long Term...Hewitt
Aviation...VJN/Hewitt
Marine...VJN/Hewitt
Area Forecast Discussion
National Weather Service Grand Forks ND
951 PM CDT Tue Jul 10 2018
.UPDATE...
Issued at 951 PM CDT Tue Jul 10 2018
Question remains how much convection we will get later tonight
along the northern tier as the complex in far northeast MT moves
east. Storms just to the south in east central MT have been
fizzling with warming cloud tops, although a few more storms have
developed in southeast MT. HRRR a few runs ago had the entire span
of ND seeing at least some precip as the convection moved east,
but latest run has significantly backed off on that solution. For
now think the storms entering NW ND have the best shot of making
it eastward into our CWA, so have POPs mainly along and north of
highway 2. Elevated CAPE will be increasing overnight, so think
there remains a threat for some hail or damaging winds across the
north although several of the CAMS keep the best cells up in
Canada. The HRRR and RAP also develop some storms over our
northeastern counties as warm air advection gets going later
tonight. Increased POPs a bit in that area also.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 338 PM CDT Tue Jul 10 2018
Tonight should be pretty quiet for the most part. Winds will stay
out of the SSE, but will remain breezy. High resolution models
show a storm complex moving into northwest ND during the late
evening, then tracking along and north of the Canadian border as
it moves east after midnight. This could spread some showers and
weaker storms into areas mostly along the Canadian border after
midnight into the early morning hours. Some of these showers and
storms may drop a little further south over northwest MN as well.
Looking ahead into Wednesday, a cold front is expected to move
through the FA. During peak heating, this front should be along or
east of the Red River Valley. Afternoon temperatures in the 80s
with dew points around 70 should provide ample heat and humidity
for storms. The main question is exactly where the boundary sets
up and when and where any storms fire. Model guidance seems to
favor the areas east of the Red River Valley by mid to late
afternoon. These storms look to track SE, so they may well last
into the evening as well. Some of these storms could be severe.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 338 PM CDT Tue Jul 10 2018
Multi-level low pressure over central Manitoba Wed eve will move to
the east overnight as trailing cold front heads into and through MN.
By this time most convection would likely be focused over NW and
west central MN with sfc based CAPES averaging between 2000 and 3000
J/kg.
Thu and Fri appear to be mainly dry in the wake of the cold front.
Upper flow will be zonal, and westerly boundary layer winds will
still lead to above average temps, generally between 85 and 90.
Return southerly flow will commence during the day Fri creating
even warmer conditions to begin the weekend. Shortwave approaches
later Sat, portending yet another risk of nocturnal convection Sat
night perhaps into early Sun. Signal for seasonally mild weather
appears early next week, dropping high temps 5 to 10 degrees below
average, translating to readings in the 70s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 654 PM CDT Tue Jul 10 2018
Conditions are VFR with cumulus field near KDVL staying around
3500 ft for ceilings. High and mid clouds will be on the increase
overnight. Another convective complex is expected to move along
the international border during the 06-12Z time frame. At this
point it seems most of the activity will be north of the TAF sites
so left out any mention for now. Southeast winds will stay in the
10 to 15 kt range with some higher gusts. Winds will eventually
shift around to the southwest, then northwest at KDVL for the end
of the period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
SHORT TERM...Godon
LONG TERM...WJB
AVIATION...JR
Area Forecast Discussion
National Weather Service Indianapolis IN
1100 PM EDT Tue Jul 10 2018
.UPDATE...
The AVIATION section has been updated below.
&&
.SYNOPSIS...
Issued at 942 PM EDT Tue Jul 10 2018
Dry weather is expected to settle across central Indiana into the
weekend. This is associated with a strong ridge of high pressure
over the plains states that will be slowly building across the Ohio
Valley. Seasonal summertime temperatures are expected.
&&
.NEAR TERM /Tonight/...
Issued at 942 PM EDT Tue Jul 10 2018
The thunderstorms should end over far south central Indiana by or
very shortly after 10 pm.
Previous discussion follows...
Issued at 615 PM EDT Tue Jul 10 2018
The storms have weakened and decreased in coverage as the outflow
has surged ahead. Expect this trend to continue with coverage
decreasing further this evening. Any lingering convection should be
south of the area by 10 pm or earlier.
Previous discussion follows...
Issued at 133 PM EDT Tue Jul 10 2018
Surface analysis early this afternoon shows a weak surface trough
stretching from northern Ohio across North Central Indiana to
Central Illinois. Scattered Cu was developing along and ahead of
the trough and Radar shows scattered showers and storms over
Northern Indiana drifting south.
Forecast soundings this afternoon continue to suggest favorable
steep lapse rates for convection with convective temperature
already reached and CAPE near 3000 J/kg. Thus with a favorable
set-up for continued storm sustainability ahead of the
approaching trough...ongoing pops ahead of the trough will be
continued through the evening hours. HRRR shows these storms
passing across much of east Central Indiana through 00Z...before
exiting to the southeast around 01Z-02Z. At that point...daytime
heating will be lost and with other minimal dynamics in play...dry
weather will be expected overnight. Little change in temps are
expected in the wake of the weak trough...thus will stick close to
the ongoing persistence type lows.
&&
.SHORT TERM /Wednesday through Friday/...
Issued at 133 PM EDT Tue Jul 10 2018
GFS and NAM show strong High pressure in place aloft over Iowa
slowly building eastward across the Ohio valley through Friday.
Ridging from the high is expected to nose across the western great
lakes and pass across Indiana through Friday. This flow show keep
any forcing dynamics well northeast of Central Indiana...Over
Michigan and eastern Ohio. Furthermore forecast soundings on
Wednesday through Friday suggest the development of a strong mid
level inversion and 700mb temps surging above 10C...which should
be quite the strong cap. Convective temperatures through the
periods are suggested to be in the unreachable 100s. Thus we will
look for sunny hot days and warm humid summer nights through
Friday. Generally will aim for temps at or slightly above the
forecast builder blends.
&&
.LONG TERM (Friday Night Through Tuesday)...
Issued at 210 PM EDT Tue Jul 10 2018
Models are close enough that the model blend initialization
was accepted for most items.
An upper high will provide hot and humid buy likely dry conditions
Saturday. The upper high will then be pushed south and west as upper
troughing develops across Canada and the northern USA.
This will allow a front to meander in the area early next week,
bringing rain chances and a gradual cool down to near normal
readings by next Tuesday.
Confidence is low to medium in timing of the PoPs and cooler
temperatures next week as models continue to shift the details.
&&
.AVIATION (Discussion for the 110600Z TAF Issuance)...
Issued at 1100 PM EDT Tue Jul 10 2018
Good confidence in VFR conditions through the TAF period per the
SREF and GFS LAMP, under the influence of high pressure and a dry
column.
Winds will be variable tonight 5 knots or less and from the east 7
knots or less after 14z.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...Puma/MK
NEAR TERM...Puma/MK
SHORT TERM...Puma
LONG TERM....50
AVIATION...MK
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
942 PM CDT Tue Jul 10 2018
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
No substantial changes are planned for this evening. Convection
continues to decrease with the loss of daytime heating and this
trend should continue over the next few hours. I backed off on
POPs for the remainder of the night, and as we are no longer
seeing lightning in our area, I have removed thunder from the
forecast for the rest of the night. Otherwise, hourly temp,
dewpoint, and wind forecasts were adjusted to reflect current
observations. /DL/
Prior discussion below:
Tonight through Wednesday:
The primary concern will be rain chances for this afternoon
through Wednesday.
The latest rap and satellite imagery show a broad mid to upper
level ridge centered over the Central Rockies. Near the
Alabama/NW Florida coast was a weak easterly wave tracking west.
Area radars were picking up scattered showers and some
thunderstorms across the region. Readings were in the mid to upper
80s. For the remainder of this afternoon expect scattered showers
and thunderstorms to continue through the early evening hours.
The activity will diminish during the overnight hours. With each
of the storms can expect locally heavy downpours with 2 inch plus
pwats, brief gusty winds and some frequent lightning. Latest CAM
guidance does not show much organization with the storms as far as
strong storm potential is concern. Expect the activity to wane as
we push through the evening hours. It will be another muggy night
with lows in the lower 70s.
For Wednesday the weak easterly wave will be positioned to our
south off the ms/la coastal areas. It will provide some additional
low level convergence for rain chances during the day. Expect the
activity to develop a little earlier in the morning. Some of the
CAM guidance shows a few strong storms over areas south of
interstate 20 during the day. It will be another warm day with
highs in the lower to middle 90s with heat indices approaching
100./17/
Wednesday night through Monday...
A front will try to drop into the region on Wednesday but appears
to wash out, leaving some diurnally driven showers and storms that
will diminish in the evening hours. The upper ridge will build
across Missouri through the remainder of the week. This will allow
for continued afternoon showers and storms across the area, but
less coverage is expected. A weakness in the ridge will occur by
the weekend and this may bring a greater coverage of storms for
Saturday and Sunday and even into Monday.
Hot and humid conditions will occur through the week. Heat indices
may reach 100 to 105 degrees in portions of the forecast area at
times. With potential for convection, temperatures may not reach
their full potential and this will also limit how high heat
indices reach. /28/
&&
.AVIATION...
00Z TAF discussion:
Away from convection, generally VFR conditions will prevail
through the evening. Where convection is occurring, lower ceilings
and visibilities, and gusty winds will briefly be encountered. The
convection looks to diminish by mid evening, followed by pockets
of light fog overnight and into early Wednesday morning. By mid
morning Wednesday, VCTS will begin developing again during the
heat of the day with the majority of this occurring around JAN,
HKS, and HBG through the end of the period./26/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 73 93 74 93 / 12 51 30 27
Meridian 73 96 74 94 / 8 29 24 37
Vicksburg 73 92 74 92 / 12 57 30 28
Hattiesburg 73 93 73 93 / 19 47 30 29
Natchez 73 91 73 91 / 19 62 32 37
Greenville 73 91 74 92 / 4 29 29 24
Greenwood 73 92 74 92 / 7 29 22 20
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
DL/17/28/26
Area Forecast Discussion
National Weather Service Louisville KY
1036 PM EDT Tue Jul 10 2018
.Forecast Update...
Issued at 1030 PM EDT Tue Jul 10 2018
Overall convection continues to fizzle over southern Indiana with
the loss of heating. However, a couple of isolated cells have been
able to redevelop, so while even 20 percent coverage is probably
fairly generous, we can`t rule out a stray shower or storm overnight
as the outflow boundary moves south into central Kentucky. Current
forecast of isolated showers and storms will be allowed to ride as-
is.
Issued at 835 PM EDT Tue Jul 10 2018
Isolated storms over south-central Kentucky have dissipated, leaving
the area dry for now. A broken line of storms is advancing southward
into southern Indiana, but already showing signs of weakening since
it has outrun the weak cold front that spawned it. Expect the
weakening trend to continue with the loss of heating.
Overnight forecast looks in decent shape, with a just-barely-
mentionable 20 POP as the residual boundary pushes south through a
very moist air mass.
&&
.Short Term...(This evening through Wednesday)
Issued at 300 PM EDT Tue Jul 10 2018
Another hot afternoon is ongoing across southern IN and central KY
with mid afternoon temps in the upper 80s and lower 90s with
dewpoints near 70 or lower 70s. This has lead to moderate
instability across the region, appreciable downward CAPE (DCAPE
values around 1000 J/kg), and diurnal cumulus. Cell development in
most areas has been slow, capped aloft coupled with a lack of
forcing. However, isolated to scattered cells are ongoing over parts
of south-central KY where earlier clouds have resulted in some cloud-
clear-enhanced low-level boundaries/mesoscale forcing. For the rest
of the afternoon into early evening, isolated cells will be possible
throughout the area, with gusty surface winds given the high DCAPE
along with brief heavy rain.
For this evening/tonight, any isolated cells over central KY should
dissipate with loss of heating. At the same time, a cold front to
our north will head south across IN. Robust convection has developed
along the front over the northern third of IN at this time, and
these cells will develop and move quickly SSE through tonight.
Latest HRRR suggests a few cells could reach south-central IN by and
after 00z, and into north-central KY later this evening. As the
boundary layer slowly cools, low-level instability and DCAPE will
wane so cells will weaken and gradually diminish in number. However,
some elevated instability will remain, so isolated showers and
storms are still possible tonight in our area ahead of the surface
front, but many areas will remain dry.
Model soundings and MOS guidance suggest some low-level clouds
and/or fog could form in some areas by tomorrow (Wednesday) morning,
so have reflected this in the grids. Otherwise, expect lows mostly
from 70-75.
On Wednesday, the front will sag south through central KY switching
surface winds to NE and slowly lowering surface dewpoints behind the
boundary. However, the front will not clear south-central KY in time
to preclude isolated to scattered convective development downstate,
mainly Wednesday afternoon along and just ahead of the front. Expect
highs in the mid and upper 80s from southern IN to east-central KY,
and around 90 in south-central KY.
.Long Term...(Wednesday night through Tuesday)
Issued at 303 PM EDT Tue Jul 10 2018
The cold front should move into Tennessee by Wednesday night,
bringing slightly drier air and cooler temperatures behind it. High
pressure near Lake Erie will keep winds generally out of the
northeast over the lower Ohio Valley through Thursday.
Strong upper level ridge over the central Plains will gradually move
eastward late this week. Temperatures will increase into the
weekend, with Saturday looking to be the hottest day of the long
term with highs in the low to mid 90s. Dewpoints will be high (~70),
so heat indices could approach or exceed 100 degrees in spots.
Mostly dry weather is anticipated through Saturday as warm air near
800mb puts a cap on any potential convective development.
A strong trough will swing out of the northern Rockies Sunday and
bring increased clouds, showers/storms and slightly cooler
temperatures for early next week. Will hold on to high-end chance
PoPs for the start of next week, though it`s likely some of those
days could see widespread precipitation as a frontal boundary
approaches and potentially stalls in the lower Ohio Valley.
&&
.Aviation...(00Z TAF Issuance)
Issued at 725 PM EDT Tue Jul 10 2018
Convection is oriented roughly east to west across central Indiana,
and outrunning the cold front as it dives southward. Main question
mark is whether it can hold together long enough after sunset to
make it into SDF, LEX, and HNB. Believe that given the orientation
of the line and its movement, all three sites stand an equal but
small chance between 03-06Z. Low-confidence forecast to include
VCTS/CB mentions, but cig/vis remain VFR.
As the line dissipates and the weakening outflow pushes south to
near BWG, the other challenge is fog potential. Proximity to the
boundary will support some fog in BWG, but will not take it into IFR
at this time. Not a very strong signal for fog in HNB, but given
last night`s performance and the crossover temp in the mid 70s, it
still looks primed to sock in, and could easily go LIFR around
sunrise. For now will just carry a TEMPO.
Winds come around to NNE by midday Wednesday, but will just keep a
solid 10 kt as the surge of cool air is not as strong behind this
front. Can`t rule out a stray afternoon thunderstorm around BWG
where the better moisture will be, but will not mention this far in
advance.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...RAS
Short Term...TWF
Long Term....DM
Aviation...RAS
Area Forecast Discussion
National Weather Service Paducah KY
618 PM CDT Tue Jul 10 2018
.SHORT TERM...(Tonight through Thursday night)
Issued at 252 PM CDT Tue Jul 10 2018
Isolated showers have dotted the landscape this afternoon, but as of
2:30pm haven`t noticed any lightning. This activity, along with a
slight chance of thunder, will continue this afternoon into the
early evening hrs. Most of this looks to dwindle by 00-01z.
However, there is some signal at additional development late this
evening/overnight, which latest RAP model depicts. This appears to
coincide with a ripple in the 500mb flow that is moving southward
along the eastern periphery of the upper level high over the
Plains states. For now, going with silent PoPs, but will need to
monitor this into the evening hrs. If it happens, best chance
looks to be over eastern half of the region. Maintained slight
chance PoPs tmrw for southern sections of west KY/se MO, where
some of the CAM models depict some isolated development.
Surface high pressure will migrate southeastward across Michigan
tomorrow, with north/northeasterly flow attempting to push drier air
into our region. Models are slowing the progression of the lower
dewpoints, and the big question is how far southwest will the push
of mid to upper 60 dewpoints make it Wednesday night into Thursday.
The latest ECMWF guidances keeps dewpoints above 70 across much of
southeast MO and southern sections of west KY throughout the short
term period. But the 12z NAM pushes mid 60 dewpoints all the way
south thru the area. Forecast reflects a blend of these solutions
for now.
With temperatures peaking in the low to mid 90s, and dewpoints into
the mid 70s, heat index readings look to top out in the 100-105
range again on Wednesday for all of southeast MO, far southern IL,
and much of west KY. Some potential that a heat advisory may be
needed for portions of this area, but will defer for now, and
mention in HWO and special weather statement.
Thursday will still be hot, but should feel slightly better with
less humid air in place, particularly across the northeastern half
of the region. We may still have heat index readings around 100
along our southern border counties in Missouri.
.LONG TERM...(Friday through Tuesday)
Issued at 252 PM CDT Tue Jul 10 2018
Models show an upper level high over the middle Mississippi and
lower Ohio valleys on Friday weakening by Saturday. Conditions will
be dry and warm Friday into Friday night. Highs on Friday will be
in the lower to middle 90s, with heat indices around 100 degrees. On
Saturday, a return of southerly winds will lead to increasing
moisture and instability across our region. A few showers and
thunderstorms may sneak into portions of southeast Missouri on
Saturday, with better chances by late Saturday night into Sunday as
dew points climb from the lower to middle 70s. Highs in the lower
to middle 90s Saturday and Sunday will result in afternoon heat
indices in the 100 to 105 degree range.
Chances of showers and storms will continue and even increase a
little for the first part of the work week as models show a cold
front approaching from the northwest. ECMWF and GFS show the front
just northwest of the PAH forecast area by 00z Tuesday, and draped
across our area Monday night into Tuesday. Dew points will remain
in the lower to middle 70s, and heat indices on Monday will again
reach the 100 to 105 degree range on Monday. Convection/additional
cloud cover on Tuesday will produce highs in the 85 to 90 degree
range, which will bring down heat indices a few degrees.
&&
.AVIATION...
Issued at 617 PM CDT Tue Jul 10 2018
Diurnal cumulus should thin out and dissipate during the early
evening across the WFO PAH TAF sites for the 00z Wednesday
issuance.
Although not indicated strongly by a majority of the high
resolution guidance, the 13km RAP suggests the passage of a
surface boundary from east central Illinois and central Indiana
southward toward the KEVV and KOWB TAF`s after 04z-06z time frame.
At this point, believe there will be renewed convective activity
over the KEVV/KOWB taf locations through 08z.
Otherwise, VFR conditions should prevail along and south of the
boundary overnight, then after the boundary passage on Wednesday
morning.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...SP
LONG TERM...RST
AVIATION...Smith
Area Forecast Discussion
National Weather Service Tucson AZ
816 PM MST Tue Jul 10 2018
.SYNOPSIS...Abundant moisture will remain in place across
southeast Arizona and lead to daily rounds of showers and
thunderstorms into this weekend. Some of the thunderstorms will
produce heavy rains and strong winds. Cooler than average
daytime temperatures will also continue due to the cloud cover
and showers.
&&
.DISCUSSION...An active thunderstorm day in many locations this
afternoon, with the hardest hit areas in parts of northwest Tucson
where heavy rainfall resulted in flash flooding. Several reports of
2 to 3 inches of rain in a short period of time were received from
the northwest side around Oro Valley and Marana. Impacts ranged from
power outages to closed roads and a Union Pacific train derailment
in Marana. In addition to the locally heavy rainfall, a few days of
rain in the Upper Gila River Basin in New Mexico will result in
elevated flows in the Gila River at Duncan and near Solomon, Arizona
tonight and tomorrow. Otherwise, today`s thunderstorms have
diminished significantly with the main activity centered south of
Ajo in western Pima county late this evening. The latest HRRR
solution continued to advertise some lingering showers and a stray
thunderstorm or two overnight tonight. Based on the overall flow
pattern and the ongoing thunderstorm activity in northern Mexico,
will keep the mention of rain chances tonight. Thereafter, abundant
moisture will remain over the region through at least this weekend
with a continued chance of showers and thunderstorms. Rain chances
and cloudiness will help keep daytime temperatures a few degrees
below normal.
&&
.AVIATION...Valid through 12/06Z.
ISOLD TSRA/SHRA will continue through 11/17Z, then become SCT
TSRA/SHRA through 12/06Z. Outside of TSRA with gusts to 40kts,
surface winds SSELY 5-15kts. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...The pattern remains favorable for isolated to
scattered thunderstorm development throughout the forecast period.
Other than strong outflows around afternoon thunderstorms, 20-ft
winds hold below 15 mph.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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