Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/17/18
Area Forecast Discussion
National Weather Service Albany NY
1054 PM EDT Thu Aug 16 2018
.SYNOPSIS...
A warm front and a disturbance ahead of a cold front
will bring showers and thunderstorms back into the region late
tonight through tomorrow. In addition, rainfall could be locally
heavy due to high moisture content in the atmosphere. The last in
the series of the these fronts moves across Saturday as a cold
front. This will end the showers and thunderstorms from north to
south and leave behind a mainly drier and calmer weather pattern for
the second half of the weekend.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 1054 PM EDT...The latest observational and 3-km HRRR and
Namnest trends continues to show a slower progression of the
showers and isolated thunderstorms moving into the ALY forecast
area ahead of the warm front to sfc low near the Upper MS River
Valley and the Upper Midwest. The boundary will be a focus for
increasing showers and isolated thunderstorms overnight. We
decreased the timing to 2-5 am west of the Hudson River Valley,
and then expanding eastward between 5-8 am.
The latest 00Z NAM indicates elevated instability with Showalter
values of 0 to -2C. The low-level jet increases from the south
to southwest transporting some subtropical moisture into the
region towards daybreak. The 00Z PWAT on the KALY sounding is
1.25" so it will take a little bit of time to moisten the low-
levels with the dry air aloft due the low and mid level ridge
hanging tough.
We also may get some radiative mist/fog over the Lake George
Region, CT River Valley into the Berkshires before the mid and
high clouds increase. We added patchy fog to the forecast in
these areas.
It will be another mild night with lows in the 60s to around 70F
across the region.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
Slight Risk with both severe weather and excessive rainfall
outlooks on Friday into Friday night...
Complex pattern setting up for the region on Friday as much will
depend on insolation and training echoes. As has been mentioned
in several excellent discussions the past several shifts, large
scale positive tilted trough axis along with the surface wave
reflection will be approaching from the central Great Lakes and
Ohio Valley. The warm front is expected to lift northward during
the morning with elevated convection accompanying its passage.
Thereafter, PWATs climb toward or above 2 inches as low level
jet magnitudes and PWAT anomalies climb toward 2 standard
deviations above normal. While heavy rainfall threat will
remain, areas to the west and southwest of Albany will be the
most susceptible for flooding concerns due to antecedent wet
conditions the past several days. Otherwise, MBE speeds of 10kts
or less could result in training echoes across the region.
Hence the excessive rainfall outlook will be upgraded to slight
risk for most of eastern NY. As for severe potential, SPC has
upgraded most of our region into slight risk with the day 2
outlook. The main consideration here will be how much insolation
we will receive after the warm front lifts north. Based on
satellite imagery upstream, there is considerable cloud coverage
at the present time as mid level lapse rates were near moist
adiabatic. HREF and CAMS members vary significantly to where the
best instability axis will occur and convective modes/trends.
While lapse rates are not too ideal, given low LCL`s and
increase instability with modest shear profiles, several multi-
cells and some bows are possible. An isolated tornado risk may
evolve for the Hudson River Valley locations where low level
channeling and veering profiles in the lowest 1km could result
in a couple supercell structures which again will be highly
dependent on sunshine. Temperatures Friday should be able to tap
out into the lower 80s for valley locations and well into the
70s elsewhere with dewpoints near 70F as well.
The region remains well embedded in the warm and moist sector
Friday night with additional convection and heavy rainfall. As
overall instability does wane, shear remains in place as well as
those high moisture content with PWATs near 2 inches. So
additional heavy rainfall threat will continue as we remain warm
and muggy once again.
The cold front is expected to move from north to south through
the day Saturday. There is excellent agreement between the
global and hires models that this front should clear our
southern zones close to 00Z Sunday. So we will have a graduated
PoPs in the forecast with showers lingering along and south of
I90 for most of the day. Dewpoints will drop back into the upper
50s across the Dacks and Lake George Region later in the day
which will slowly advect southward heading into Saturday night.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
The weather will be dry at both the beginning and end of the period,
with rain in between. High pressure will dominate the first 48
hours. This will give in to an area of low pressure which will
track from lower Michigan to southern Quebec Tuesday and Tuesday
night. Rainfall could be significant Tuesday night, but things
zip through as the stagnant pattern of mid-summer finally begins
to change.
The cold front associated with this system is expected to slide east
across our forecast area Tuesday night into early Wednesday. This
will be replaced by a broadening dome of high pressure...centered
over the Ohio Valley early Thursday, resulting in comfortable
conditions with lowering humidities, increasing daytime sunshine,
and temperatures that are near or slightly below normal with little
day-to-day variation.
High temperatures prior to the frontal passage will range from the
upper 60s to upper 70s each day...and thereafter...from the mid 60s
to lower 80s. Overnight lows initially will be in the mid 50s to
lower 60s, with a brief pre-frontal boost of a few degrees Tuesday
night, then back down...to around the 50 to 60 degree range for
Wednesday night.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
High pressure that briefly ridged in today will shift eastward,
as the weak cold front lifts north as a warm front overnight
into tomorrow. A prefrontal trough and a cold front will focus
showers and thunderstorms tomorrow afternoon into the evening
period.
VFR conditions are expected prior to midnight with just
scattered to broken cirrus. The mostly clear skies, and calm
winds will allow for some radiational mist or fog to form. The
favored climatological fog sites of KGFL/KPSF have the best
chance of IFR vsbys between 04Z-09Z/FRI. Some MVFR mist is
possible at KALB/KPOU, but then the mid and high clouds will
increase. The isentropic lift with the warm front will focus
some showers and elevated thunderstorms. PROB30 groups were
used at KGFL/KALB between 09Z-13Z and 10Z-15Z. The threat
expands eastward into KPSF/KPOU between 12Z-16Z. Conditions will
lower to MVFR/IFR levels in the showers and thunderstorms.
Another round of showers and thunderstorms, some of which could
be strong to severe are possible between 18Z/FRI to 00Z/SAT.
IFR/MVFR conditions are possible in the thunderstorms. Later TAF
issuances will have to pinpoint the timing for the
thunderstorms. PROB30 groups were used for now. Conditions in
terms of cigs will likely be VFR/high MVFR ahead of the showers
and thunderstorms.
The winds will be light to calm tonight, and then increase from
the south to southeast at 5-10 kts in the late morning into the
afternoon. KALB due to funneling up the Hudson River Valley
could be a little breezier with southerly winds of 10-12 kts
with a few gusts approaching 20 kts in the afternoon.
0utlook...
Friday Night: High Operational Impact. Likely SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA.
Saturday Night to Tuesday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Minimal to no fire weather related concerns as higher moisture
content will advect into the region tonight with showers and
thunderstorms increasing late tonight and through most of
Friday. Rainfall could be locally heavy. This will keep relative
humidity values elevated through at least Saturday. Conditions
dry out Saturday night and into Sunday.
&&
.HYDROLOGY...
Slight Risk of Excessive Rainfall across most of eastern New
York into Friday...
Showers and thunderstorms will be on the increase overnight and
into Friday. Combine that with higher moisture content will
potentially result in heavy rainfall and training thunderstorms.
Portions to the west and southwest of Albany have higher
antecedent conditions with wet soils compared to the
Adirondacks and portions of the southern Greens. However,
convection with heavy rainfall can quickly change those drier
areas as we will continue to monitor trends closely. Flash flood
guidance across portions of the Mohawk Valley, Schoharie Valley
and Catskills are generally between 1.5-2.5 inches within 1-3
hours respectfully. The values are a bit higher to the east of
those areas. Per coordination , if confidence levels increase
then Flash Flood Watches would be needed.
Showers will linger into Saturday, before high pressure builds
in with a dry stretch of weather expected for Sunday into early
next week.
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/Wasula
NEAR TERM...Wasula
SHORT TERM...BGM
LONG TERM...ELH
AVIATION...Wasula
FIRE WEATHER...BGM/JPV
HYDROLOGY...BGM/JPV
Area Forecast Discussion
National Weather Service Bismarck ND
909 PM CDT Thu Aug 16 2018
.UPDATE...
Issued at 908 PM CDT Thu Aug 16 2018
No major changes required for this update.
UPDATE Issued at 545 PM CDT Thu Aug 16 2018
Increased smoke coverage and duration with this update. A rather
pronounced area of smoke is encompassing the northern half of
North Dakota this evening as seen on satellite and web cameras.
The mid/upper level flow pattern and latest run of the HRRR smoke
model indicate smoke will likely remain through the day tomorrow
and maybe even into the weekend.
&&
.SHORT TERM...(This evening through Friday)
Issued at 321 PM CDT Thu Aug 16 2018
The challenge with the short term is how far south the smoke will
shift out of Canada. Current satellite observations show smoke
entering northern North Dakota this afternoon. Current
visibilities in southern Manitoba and Saskatchewan are ranging
between 4 to 6 SM. HRRR Near-Surface smoke model guidance suggests
this plume of smoke will continue to push south throughout the
rest of the afternoon into tonight. The current forecast has
northwestern and north central North Dakota with patchy smoke now
through the overnight hours. Will need to continue to monitor to
see how far south the smoke shifts throughout the afternoon and
overnight.
An upper level ridge builds over eastern Montana and western North
Dakota Thursday night into Friday, bringing sunny skies and
temperatures in the upper 80s to mid 90s on Friday.
.LONG TERM...(Friday night through Thursday)
Issued at 321 PM CDT Thu Aug 16 2018
Chances for showers and thunderstorms Saturday night and Sunday
highlight the extended forecast.
The upper level ridge remains in place Friday night into early
Saturday, allowing temperatures to rise into the low 90s. A
shortwave and attendant surface cold front break up this upper level
ridge, passing through North Dakota Saturday night into Sunday. This
will bring chances for widespread showers and thunderstorms to the
area. A few strong to severe thunderstorms are possible, mainly in
southern North Dakota given moderate MUCAPE (2000 J/Kg) and weak
bulk shear (20 kts). Behind the cold front, a stable and cooler air
mass moves in Sunday as showers and a few thunderstorms linger
across the area. Highs are expected to only be in the 70s Sunday
through Tuesday. A shortwave passes through the area on Monday,
bringing a chance of showers to the far western part of North
Dakota. Temperatures will rise back into the 80s and lower 90s by
midweek. Another shortwave is possible Thursday that could bring
thunderstorms to the northern part of the state.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 545 PM CDT Thu Aug 16 2018
Aside from the smoke, VFR conditions are expected with light and
variable winds becoming southerly near 10 kts by Friday
afternoon.
Visible satellite imagery shows smoke settling in across northern
North Dakota. Surface visibilities have not been reduced much
yet. However, widespread MVFR visibilities have been observed
across much of central and southern Saskatchewan so far today.
While this thicker smoke may be transported into North Dakota
later today and tonight, confidence on MVFR visibility at KISN and
KMOT is not high enough to include at this time. A period of MVFR
visibility may need to be added in future TAF issuances.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AJ
SHORT TERM...BRM/Hollan
LONG TERM...BRM/Hollan
AVIATION...AJ
Area Forecast Discussion
National Weather Service State College PA
1102 PM EDT Thu Aug 16 2018
.SYNOPSIS...
A weakening cold front will push through the area Friday. A
secondary cold front will move across the state Saturday
followed by slightly cooler air and more comfortable humidity
for the second half of the upcoming weekend.
&&
.NEAR TERM /UNTIL 7 AM FRIDAY MORNING/...
Disorderly and barely noteable convection roaming around the
region right now, as earlier storms have dissipated. A fight
between NVA aloft and sfc convergence is occurring over NW PA,
NE OH at this time. Result: Numerous showers but little
organization. A cluster of showers in central WV is slated to
arrive in the Scent mtns before sunrise, but time of day argues
for the showers to remain garden variety and sct at worst. The
QPF for the NW third of the area from almost all guidance seems
overdone overnight. The newest NAM seems to have a decent trend,
with mainly sct shra and only light qpf thru the night over the
NW half of the area. The next influx of decent organization may
come with the forcing over the OH/IN border. That should arrive
just after sunrise in the west.
Prev...
Multiple clusters of storms rolling across the area. None
seeming particularly dangerous but some are exhibiting a
tendency to hold a good reflectivity core aloft for a short
time. Rainfall is briefly heavy, but most top out in the
0.5-0.75" max per hour.
Main changes with this update were to refine PoPs in the
period. There should be a short lull behind this current
shortwave trough/vort max over the west, then perhaps a
resurgence of the storms -mainly in the NW- as the next upper
forcing rolls in along with a bit of an increase in 8H wind.
But, that forcing wanes by morning. Much of the night looks dry
in the SErn few counties, but a stray shower cannot be ruled
out.
Prev...
Satellite is showing a gradual increase in mid and high
cloudiness out ahead of a shearing shortwave moving out of the
OH Valley. The first small cells are starting to break out from
just west of IPT back to Elk County. The latest HRRR shows the
most organized showers and scattered thunderstorms spreading
across the NW portion of the CWA after 22Z/6PM this evening.
All Hi-Res CAMS and other regional scale models keep the SE
third to half of our CWA dry through most or all of this
afternoon and tonight.
Ensembles confine the best surge in PWATs up into my NWRN zones
this evening and overnight. This is also where they paint the
highest probs of seeing a quarter inch of rain or more through
Friday morning. This implies the showers over central and
eastern areas will be more scattered in nature. The HRRR
supports this, keeping the bulk of its rain along or north of
I-80.
Overnight lows will be well above normal ranging from the mid
60s over the north to lower 70s over the SE.
&&
.SHORT TERM /7 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
The axis of high PWAT air will slide across the NW portions of
PA and the Laurel Highlands during the morning hours Friday. The
close proximity of this feature and approach of one or more
weak mid/upper short waves embedded in the SW flow aloft will
maintain the chances for intermittent showers and scattered
thunderstorms.
For Friday afternoon, the weakening remnants of the surface
cold front are made to hang up over central or eastern PA.
Models are generous in creating a fair amount of CAPE in the
humid airmass so expect an uptick in thunderstorm activity
during the afternoon into the evening. SPC has the area under a
Marginal Risk for severe storms which looks reasonable.
Damaging wind gusts will be the main threat mainly along/east of
the Susquehanna River. Saturated ground will make it easier for
gusty storms to topple trees and cause power outages.
In addition, with many areas experiencing record or near record
summer rainfall totals, more heavy downpours will pose an
isolated risk of localized flooding.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
Leftover convection should generally decrease in coverage and
intensity Friday night. Models show the best chance for
lingering showers/storms over the western Alleghenies.
A trailing frontal wave of low pressure will likely bring
another round of showers/storms across the southern 1/2 to 1/3
of central PA during the day on Saturday. Above-normal moisture
(PW) pooling along the east-west boundary will support risk for
heavy downpours/marginal risk of flash flooding. Latest model
trends have remained supportive of an increase in precip probs
into Saturday night with some north-to-south clearing expected
by early Sunday.
We are still favoring mainly dry weather Sunday into Monday.
However, the 16/12Z ECMWF is less optimistic on Sunday over the
southern tier of central PA. A spotty/isolated P.M. shower or
t-storm is possible on Monday over the southern Alleghenies, as
south/southeast flow brings increasing moisture back into the
area.
Models and ensemble continue to track a mature cyclone through
the Great Lakes early next week. The well-defined trailing cold
front will trigger T-storms as it crosses the Alleghenies
Tuesday into Tuesday night. A severe storm and heavy rain/flash
flooding risk may accompany the frontal passage before a push
of drier air delivers a possible stretch of rain-free days later
next week. PoPs were increased by 10% or so on Tuesday based on
a multi-model/ensemble blend.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Isolated showers about all that is left as of 11 PM.
Main issue later will be some fog.
Earlier discussion below.
Storms fell apart just south of State College at 5 PM.
However, typical of this summer, activity has picked up again
after sunset, mainly in the State College area.
TAFS updated for the activity.
Main issue late will be some fog.
For Friday, went with VCSH for now.
Some improvement possible for the weekend, mainly across the
north on Sunday.
.Outlook...
Fri...Cold front will bring more numerous showers/tstms areawide
with local restrictions.
Sat...Still a chance of showers and storms, mainly across the
south early on.
Sun-Mon...Mainly VFR.
Tue...Restrictions developing with showers and thunderstorms.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Dangelo/La Corte
NEAR TERM...Dangelo/La Corte
SHORT TERM...La Corte
LONG TERM...Steinbugl
AVIATION...Martin
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1045 PM EDT Thu Aug 16 2018
.UPDATE...
Issued at 1045 PM EDT THU AUG 16 2018
Did a quick update to the grids to handle the near term radar and
sky cover trends as well as the latest CAMs guidance through the
rest of the night. Will be on the lookout for heavy rain potential
in the Bluegrass area later tonight where training could become a
concern by dawn. Otherwise, have updated the grids through
morning with the inclusion of T/Td obs and trends. These have been
sent to the NDFD and web servers. An updated ZFP will hit the
streets shortly as well.
UPDATE Issued at 735 PM EDT THU AUG 16 2018
23z sfc analysis shows low pressure off to the northwest of the
area with the local pressure field overwhelmed by the meso high
associated with the early storms that progressed through the area
over the past few hours. These have mostly dissipated to just
light showers and sprinkles with the last cell near LOZ weakening
rapidly. The latest HRRR and other CAMs indicate that the rest of
the evening into the first part of the overnight will be rather
quiet before another round of convection is expected to develop to
the west or overhead towards dawn. Have depicted this in the
grids going forward through dawn with this update. Did also add in
some moderate fog in the river valleys after midnight as the
clouds thin over the area and some radiational cooling will be
possible. The cooling will be limited by the high dewpoint air in
place with current obs in the upper 60s to lower 70s. Meanwhile,
temperatures are in the low to mid 70s while winds, away from any
convection, are generally light from the southwest. Have also
updated the grids to add in the latest obs and trends for the T/Td
ones. These grids have been sent to the NDFD and web servers. An
update to the HWO and zones will be forthcoming once the last of
the convection fades.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 415 EDT THU AUG 16 2018
Current conditions across the area feature a swath of showers and
embedded showers and thunderstorms crossing the I-75 corridor
this hour along with a few discrete pop up cells ahead of the
swath moving eastward as well. Relatively rain free area over the
eastern portion of the area has resulted in some instability
developing and this is seen on the current radar returns as some
strong cells have developed and will be moving through the area
into this evening. Model soundings suggest good instability
lingering into the overnight hours as the cold front to the
northwest slowly tracks into Kentucky. Due to this, will expect
convection lasting across eastern Kentucky past 00z. Cams do
suggest a brief break this evening into early tonight before
convection reinvigorates later tonight into tomorrow as the front
approaches the area. In fact, there may be some fog development in
the valleys if there is any clearing behind the first swath of
showers and thunderstorms.
Heading into the day on Friday, PWATs will remain in the 1.75 to
2.00 inch range through the day. With the amount of moisture and
skinny CAPE shown by the model soundings, the threat of flooding
will continue through the day and into Friday night. From the
activity today, guidance will take a hit, especially the basins in
the south. Thus flooding concerns will something that needs to be
monitored, especially cells that begin to train over the same
area. Model soundings and CAMs suggests that precip chances will
linger into the Friday night period as well. This is in agreement
as well with operational models as the front will eventually stall
over the eastern portion of the state leading into the Friday
night hours.
.LONG TERM...(Saturday through Thursday)
Issued at 350 PM EDT THU AUG 16 2018
The majority of the long term will feature a continued dynamic
pattern. A shortwave trough will make its way through the Ohio
Valley this weekend. A brief period of drier conditions will occur
early Monday due to a weak upper level ridge. Then, a deep upper
level trough will progress over the Ohio Valley through Wednesday
before moving to the northeast Thursday. At the surface, a slow
moving front will bring daily chances of showers and thunderstorms
through the weekend. A brief lull in precip will occur early Monday,
then a warm front associated with a low pressure system located in
the Central Plains will bring increased chances for showers and
thunderstorms Monday afternoon and evening. As the low pressure
system moves northeast over the Great Lakes Tuesday, a cold front
will advance towards the Commonwealth. Shower and thunderstorm
potential will increase with the passage of this cold front through
mid week. Drier conditions will return to eastern Kentucky Thursday
as a surface high pressure builds over the region. Overall, the
models are in fairly good agreement and therefore, did not stray too
far from the Blend beyond some minor adjustments.
Through Tuesday, high temperatures will be in the low to mid 80s
with low temps generally in the mid to upper 60s. Frontal passage on
Wednesday will cool down temperatures to be around 60 degrees in the
morning with highs only reaching the upper 70s. Highs will increase
slightly to be in the low 80s to round out the long term period
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
ISSUED AT 800 PM EDT THU AUG 16 2018
Current radar trends are showing the limited convection fading
out and drifting east this evening. Expect a lull in activity
through the first part of the night per the CAMs before addition
showers and some thunderstorms develop over the area or just to
the west in the pre-dawn hours. Valley fog can be expected late
tonight but likely having limited impact on the TAF sites. The
better potential for thunderstorms will come Friday morning and
into the afternoon as the cold front moves closer towards the
state. VCTS and a period of prevailing TSRA are mentioned for each
TAF site with the exception of SJS since the better threat for
any thunderstorm activity at this site may occur late in the
period, if at all. Visibility will also lower to at least MVFR
conditions in thunderstorms and CIGs may touch on MVFR, for a
time. Winds will generally be out of the southwest at around 5
knots, but be higher in and near thunderstorms.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...SHALLENBERGER
LONG TERM...CGAL
AVIATION...GREIF
Area Forecast Discussion
National Weather Service Louisville KY
900 PM EDT Thu Aug 16 2018
.Forecast Update...
Issued at 900 PM EDT Thu Aug 16 2018
Convection this evening has been rather weak, but seems to be best
organized north of the river from northern Harrison into Jefferson
counties in southern Indiana. Further south, convection has been
rather sparse with a few pop up showers here and there. Activity
has increased slightly over the last half hour or so. Latest HRRR
runs continue to show convection redeveloping this evening, in areas
mainly east of the I-65 corridor. Have gone ahead and bumped up
PoPs a bit to bring them up faster in time than previously. In
general, we believe that scattered convection will be most likely
over our southern IN and east-central KY locations through the
overnight. Severe weather doesn`t look likely given the weak-mid
level lapse rates and being near the nocturnal instability minimum.
However, the low-level jet and isentropic lift will help offset
things to keep convection going.
Further west, sharp upper trough axis will pivot in from the
northwest. HRRR has a decent handle on the convection over northern
MO and west-central IL. This activity is expected to continue to
develop overnight and then spread southeastward into southern IN and
central KY towards dawn Friday. This will likely result in another
wet AM commute for many areas with heavy rain being possible.
Organized severe weather doesn`t look likely with this activity.
Heavy rainfall appears the be the main hazard which may result in a
renewed flooding threat for our southern IN and far northern KY
counties.
Issued at 729 PM EDT Thu Aug 16 2018
Did a quick update to lower PoPs and sky cover across the region
with the departure of earlier convection. Latest HRRR runs suggest
that convection will refire over southern IN and north-central KY in
the next few hours. GOES-16 visible imagery does show an agitated
Cu field developing a few showers have sprouted across southern IN
and in portions of northern KY (north of the Parkways). Mesoanalysis
does show some increase in instability due to the late day heating.
CAPE values are in the 1000-1300 J/Kg with very weak bulk shear
values. Low level lapse rates are OK at 6-7 C/km though the mid-
level lapse rates are much weaker.
Current thinking is that we`ll see some weak convection continue to
develop and utilize the available instability. Question is how
strong/widespread could this activity become. Best chances look to
be north of the Parkways in KY through the evening hours. A
secondary round of convection looks to swing in here late tonight.
Will get into the details of that in a later update.
&&
.Short Term...(This evening through Friday)
Issued at 305 PM EDT Thu Aug 16 2018
...Round 1 of storms pushing east...
...Convective uncertainty late tonight into Friday....
Well...The widespread advertised rain event is pushing east of the I-
75 corridor except for southern extent of the convection along KY/TN
border where some cloud top temps of -62C exist. The Lake Cumberland
counties will have to be watched for any localized heavy rain
issues.
The sun is peeking out west of I-65 which will allow some afternoon
mixing and get SW winds to gust to 15-20 mph through sunset. After
a lull in precip over most of the region tonight, muggy conditions
will continue with dewpoints hovering in the lower 70s. There could
be spotty showers/storms but for now we appear to be in a lull...
although the latest HRRR keeps sct convection with afternoon heating
over IL/W KY and moves east. With no widespread additional
convection expected in the near term, will let the Flash Flood Watch
expire on schedule at 20 UTC (4 pm EDT).
Next on the horizon, we await the vigorous next vort max. A fairly
stout upper low will dive out of the SD/NE/IA border and be the
trigger for more convection towards daybreak tonight from the Show
Me State eastward. PWATs will remain high so we will need to watch
radar and KY Mesonet precip trends late tonight and Friday. Around
12z the rain showers and storms will spread farther south and east
into central and eastern Kentucky. SPC Day 2 seems reasonable with a
marginal risk for isolated wind potential.
Temperatures will stay mild overnight in the lower to mid 70s and
may struggle again with rain and cloud cover. My plan is to lower
highs to around 80 except down in southern KY where mid 80s looks
good with mid and late day sun.
.Long Term...(Friday night through Thursday)
Issued at 305 PM EDT Thu Aug 16 2018
...Very transitory with some active weather expected during
the extended forecast period...
Friday night and Saturday...
Shortwave trough aloft will progress slowly across the Ohio Valley
during the period. At the same time, a weak surface boundary will
sag southeast across our forecast area and either go stationary or
wash out. On Friday night, models suggest up to 30 kts low-level
flow from the SW, which could contribute to additional showers and
storms. Location and coverage will be dictated by how convection
plays out during the day Friday. In any event, additional heavy rain
potential exists Friday night, mainly over central KY.
On Saturday, deeper moisture and forcing should slide east with the
upper trough, but residual moisture, instability, and weak surface
boundary(ies) will remain resulting in isolated to scattered
convection, especially in the afternoon and along and south of the
Ohio River. Widespread heavy rain is not expected Saturday, but
individual cells could still be efficient rain producers. Expect
high temperatures in the lower and mid 80s.
Sunday...
Sunday remains the day with the best chance to dry out between the
exiting system and the next system approaching from the west.
Nevertheless, isolated afternoon convective cells are still possible
in parts of central KY where some instability will remain, but even
there many areas should remain dry. Highs Sunday afternoon should
reach the mid and upper 80s.
Monday through Thursday...
The next weather system will quickly dig across the central U.S. and
MS River Valley during the period. This anomalous, stout trough
aloft will result in unusually deep/strong surface low development
for mid-late August. The low will develop over the central U.S. and
then race NE into the Great Lakes states Monday night and Tuesday.
The 12 UTC GFS/ECMWF/GEM actually are in pretty good agreement with
this, albeit some timing differences and the GFS is weaker in its
surface low strength than the other models.
Regardless, initial warm advection ahead of this system should
produce at least a round of showers and scattered storms Monday
afternoon and/or night across our area with additional convection
along the trailing cold front Monday night or Tuesday. With moderate
instability forecast along with some deep-layered shear and
favorable mid-upper jet pattern, some strong and potentially a few
severe storms are possible, probably in the form of a convective
line or line segments over the mid MS and/or OH River Valleys during
this period.
Models then show a secondary trough digging southeast late Tuesday
and Wednesday on the heals of the first trough Monday and Tuesday.
This system could keep a chance of showers in the forecast for
Tuesday night and Wednesday. Dry weather should finally arrive again
by Thursday. These systems also will usher in cooler weather and
much lower humidity with highs Wednesday in the upper 70s and lower
80s, and generally lower 80s Thursday.
&&
.Aviation...(00Z TAF Issuance)
Issued at 722 PM EDT Thu Aug 16 2018
Convection has largely moved out of the area, with the exception of
a few storms up along the I-71 corridor between KSDF and KCVG.
Latest CAMs suggest more convection developing in the KEVV-KOWB-KSDF
corridor this evening. GOES-16 visible imagery does show some
agitated Cu field across southern IN and northern KY with a few
cells trying to develop. For now, plan on keeping some VCSH early
at KSDF and KHNB. Will have to watch to see if the HRRR is right in
developing more convection in this area tonight.
Otherwise, after sunset, we should see a stratus deck develop and
lower at all the sites. Didn`t take things down as low as the
previous forecast based on the latest data. However, next round of
convection is expected to develop out across MO/IL and slide into
the region after 17/10Z. This activity may affect KHNB by 17/09Z
and then KSDF/KBWG in the 17/11-12Z time frame and then KLEX by mid-
late morning.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update.......MJ
Short Term...JDG
Long Term....TWF
Aviation.....MJ
Area Forecast Discussion
National Weather Service Lubbock TX
614 PM CDT Thu Aug 16 2018
.AVIATION...
VFR expected through the forecast period as thunderstorm activity
to the west of all three terminals diminishes near sunset tonight.
&&
.PREV DISCUSSION... /issued 307 PM CDT Thu Aug 16 2018/
DISCUSSION...
A center of high pressure has continued to expand across the most of
Texas this afternoon as shown RAP analysis. The decaying MCS from
overnight that gave some of our northern counties some decent rain
has floated into north-central OK, where it`s beginning to find some
rejuvenation. Storms have begun across the mountains of NM and
should slowly drift towards TX late this evening. As for these
affecting our forecast area overnight, our neighbors to the north in
the Amarillo area look to most likely be the benefactors, though a
bit of the complex may hold on to impact some of our northern
counties.
Friday will be warmer as the high expands across the region one more
time. One caveat, should our northwestern counties get rainfall
again tonight, the forecasted highs in this package may need to be
pulled down a degree or two thanks to the moist ground from last
nights` copious rain. Now, back to the high. All models, save the
ECMWF, have the high expanding back across our region along with
a high at H700. Yet, several CAMs want to convect Friday afternoon
in our forecast area. It`s a hard sell. Decided to pull PoPs down
significantly from the Blend output until the evening/overnight
hours as the high retreats and convection from NM can drift into
the region. With the retrograding high, weak NW flow may develop
on Saturday allowing for another shot at rain. By Sunday, a front
pushes through, and models are beginning to show the best rain
chances from it may be across the eastern two-thirds of the
forecast area, with deeper rain developing south of us.
By next week, models begin to part ways a bit too much to put much
value in high PoP forecasts. An example, the GFS pulls a front
through on Tuesday afternoon with no rain but with a glancing blow
of NW flow storms that night. On the other hand, the Euro brings the
front in the next day with quite a bit of rain. It seemed a bit
aggressive at this time to keep with the high PoPs of the Blend next
week with too much uncertainty, so this package includes lowered and
smoothed PoPs through the end of the forecast period.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
55/99/99
Area Forecast Discussion
National Weather Service Midland/Odessa TX
606 PM CDT Thu Aug 16 2018
.DISCUSSION...
See 00z aviation discussion below.
&&
.AVIATION...
VFR conditions are expected outside of thunderstorms.
Thunderstorms will continue to impact the area for the next few
hours and should primarily affect FST and PEQ. Will amend as
needed if storms move close to the other terminals. Mainly light
southerly winds are expected outside of areas of thunderstorms.
&&
.PREV DISCUSSION... /issued 226 PM CDT Thu Aug 16 2018/
DISCUSSION...As of 2:00 PM CDT Thursday...The old saying "Fool me
once shame on you fool me twice shame on me" applies to this
meteorologist. Yesterdays convection spread further than any of
the short-tern CAM models indicated...basically Mother Nature
couldn`t care a less what the models showed. Well...I`m not going
to fall for that nonsense a second day in a row!
Currently KMAF radar is indc an earlier beginning of convection
in the Davis/Guadalupe/Sacramento Mtns and adjacent Plains. An MCS
that rolled thru the northern Panhandle has dropped an outflow
boundary into the north-central CWA. Since the flow is weak there
is no doubt other outflow boundaries lurking in the area that are
too small to be discerned by the 3km CAM models such as the HRRR
and the NAM Nest. Therefore...have kept pops more extensive than
the models...similar to what last nights forecaster had (to give
him credit). Even with the ridge strengthening overhead a
combination of intense heating...ample moisture...and remnant
outflow boundaries will lead to more extensive pops beyond what
the CAM models show. Storms will form in the aftn over the Sangre
De Cristo Mtns of north-central New Mexico and develop into an
MCS as they roll east overnight into the Panhandle. This will
continue each day into the CWA thru Saturday. Temps will remain
hot hot and hot with mid/upper 90s across most of the area...with
temps just lightly kissing the century mark in the Trans Pecos and
along the Rio Grande Valley.
On Sunday a strong shortwave will drop southeast thru the northern
and central Plains as the center of the ridge becomes centered
over the AZ/NM border. As the shortwave passes east a cold front
(in name only) will drop south over the area bringing a chance of
showers/thunderstorms Sunday aftn/night. It looks like the front
will wash out as it stalls across the CWA. Whereas Sunday will
be...sigh...hot again Monday could "cool" into the lower to mid
90s! Celebration time!
It looks like the remainder of next week will feature the ridge
nearly stationary over the AZ/NM border with impulses dropping
south into the CWA around the ridge. This pattern would favor
overnight convection/MCS with each impulse combined with the
nocturnal LLJ. As of now...which is of course subject to
change...the best chances for nocturnal convection will be Tuesday
night/Wednesday morning and Thursday night/Friday morning. Temps
will remain hot (what else is new) but near normal with highs
mainly in the lower 90s. Fall can`t come soon enough!!
Strobin
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 75 97 75 99 / 10 10 0 0
Carlsbad 71 96 71 97 / 20 20 20 30
Dryden 73 97 73 99 / 10 0 0 0
Fort Stockton 72 96 71 98 / 20 10 0 20
Guadalupe Pass 70 89 68 91 / 20 30 30 40
Hobbs 70 93 69 94 / 10 10 20 20
Marfa 61 88 62 88 / 30 30 10 40
Midland Intl Airport 75 97 75 98 / 10 10 0 0
Odessa 75 97 74 98 / 10 10 0 0
Wink 75 99 74 100 / 20 20 10 20
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
NM...None.
TX...None.
&&
$$
99/99/
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1012 PM EDT Thu Aug 16 2018
.SYNOPSIS...
High pressure will extend over the area from well offshore
through the weekend with a weak trough over the central part of
the state. A cold front will move slowly through the area
next Wednesday into Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
As of 1005 PM Thursday...Adjusted forecast to add slight chance
POPs west of Hwy 17 through 2 AM with isolated activity
continuing to SW, NW and NE. Latest HRRR indicates this activity
persisting next few hours, then isolated threat along coast
overnight. Rest of forecast on track with muggy low temps in mid
to upper 70s.
/Previous discussion/
As of 230 PM Thursday...High pressure centered offshore will
continue to ridge into the area tonight. Isolated to scattered
showers have developed across the region this afternoon, most
concentrated along the sea breeze along the Crystal Coast and
far NE sections. Expect activity to diminish with loss of
heating this evening but high-res models showing a weakness in
the ridge with a few showers continuing near the coast so kept
20% PoPs in this area most of the overnight. Could see some
patchy light fog in sheltered locations inland late but guidance
keeps light winds and couple degree dewpoint depression so not
anticipating any widespread fog. Lows tonight will generally be
in the mid 70s.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH 6 PM FRIDAY/...
As of 330 AM Thu...High pressure continues to ridge into the
area from offshore while a robust upper trough pushes east
across the Mid-west states. A moist and unstable airmass
persists across eastern NC with weak shortwave energy moving
through SW flow aloft bringing scattered showers and
thunderstorms across the region through the afternoon. Not
anticipating storms to reach severe limits with very little
shear present. Highs expected in the lower 90s inland to
mid/upper 80s along the coast.
&&
.LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/...
As of 315 AM Thursday...A mean upper trough is forecast over the
Eastern US through the period while low level southerly flow
continues to circulate a very moist airmass across our region
with PW values AOA 2". The favorable combination of forcing
aloft and moisture/instability in the low levels will result in
unsettled conditions late this week through the middle of the
upcoming week with precipitation chances at or above normal and
temperatures at or slightly below normal.
Saturday through Wednesday...Shower and thunderstorm chances
increase above climatological norms through most of the period
as conditions become favorable for scattered to numerous showers
and thunderstorms. Temps are expected to be near normal with
highs inland around 90 Sat, then cooling slightly to the mid to
upper 80s Sunday through mid next week.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Short Term /through 00Z Saturday/...
As of 800 PM Thursday...VFR expected to prevail through most of
period. Lingering isolated evening tstms will avoid TAF sites
and any overnight activity will be along coast. Cannot rule out
local sub-VFR stratus at KOAJ and KISO that has occurred past
several mornings but not seeing enough forecast support other
than peristence, thus not enough confidence to include in this
TAF issuance. A bit more tstm coverage expected Friday afternoon
and included VCTS all sites.
Long Term /Friday night through Monday/...
As of 315 AM Thursday...Scattered to numerous showers and
thunderstorms will produce sub VFR conditions at times through
the period. In addition conditions will be favorable for periods
of low clouds and fog early each morning.
&&
.MARINE...
Short Term /Through Friday/...
As of 1010 PM Thursday...no changes with update.
/Previous discussion/
As of 3 PM Thursday...High pressure remains centered offshore
with a thermal trough inland and a mid-level system approaching
from the NW. Gradients between these systems gradually tighten
through the period bringing increasing winds and seas. Across
the water north of Oregon Inlet and Albemarle Sound and rivers,
expect SW winds around 5-10 kt increase to 10-15 kt tonight
into Friday, then to 15-20 kt by late Friday afternoon. South
of Oregon Inlet and Pamlico Sound will see SW winds around 15 kt
tonight into Friday, perhaps a bit stronger at times, increase
to around 20 kt by late Friday. Seas expected around 1-2 ft
northern waters and 2-3 ft southern and central waters through
the period building to 2-3 ft north and 2-4 ft south tonight and
Friday.
Long Term /Friday night through Monday/...
As of 315 AM Thursday...Little change to the surface pattern of
a trough of low pressure inland and high pressure offshore into
early next week producing S-SW flow 10-20 kt through Sat night.
Could see conditions approaching Advisory levels over the
southern and central waters Fri night into Sat night as the S-SW
flow increases to 20 kt with higher gusts. Seas of 2 to 4 ft
late Fri will build to at least 3 to 5 ft Fri night through Sat
night with the Wave Watch wave model indicating 6 ft seas
possible over the outer southern and central waters. The flow is
forecast to become westerly and diminish to 10-15 kt Sunday
with seas subsiding to 2 to 4 ft. Monday the flow will briefly
become easterly 10 kt or less over the Sounds and northern and
central waters, while becoming SW 10 kt or less over the
southern waters. Seas are forecast 2-4 ft.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...SK
NEAR TERM...JBM/SK
SHORT TERM...SK
LONG TERM...JME
AVIATION...JME/JBM
MARINE...JME/JBM/SK
Area Forecast Discussion
National Weather Service Marquette MI
631 PM EDT Thu Aug 16 2018
.SHORT TERM...(This evening through Friday)
Issued at 421 PM EDT THU AUG 16 2018
Updated for note on wildfire smoke that will move across the area
on Fri.
Water vapor imagery and RAP analysis show zonal flow across much of
Canada. In the weaker flow to the s, a well-defined shortwave is
over nw IA/ne NE/se SD/sw MN. With daytime heating, sct shra/tsra
associated with the wave have been increasing across IA/southern MN
into sw WI. It appears a subtle wave ahead of the main feature has
also been aiding some shra/tsra development farther ne in WI. Closer
to home, quite a bit of cloud cover has helped slow build up of
instability. That said, latest SPC mesoanalysis shows mlcapes have
increased to 1000+j/kg from northern WI toward Marquette.
Aforementioned well-defined shortwave is fcst to shift ese and
weaken tonight/Fri. While it won`t have any direct impact on the
weather here, avbl instability and subtle wave in WI should support
development of a few shra/possibly a tstm across the border into
portions of central Upper MI over the next several hrs. Vis
satellite imagery indicates CU are becoming more well-developed in
the area bounded roughly by Ironwood/Marquette/Iron Mtn, which
supports the idea that some shra may develop late aftn/early
evening. Very weak mean wind under 10kt will lead to little movement
of any shra that develop. Shra should end by midnight, though some
models hint that pcpn could linger overnight. Light/calm wind,
decrease in clouds overnight, and temps falling into 50s will likely
lead to some radiation fog development over the interior w half.
Fri looks like a quiet day. However, under a slightly more wnw mid-
level flow, models do show a weak shortwave approaching in the aftn.
There is some TCU developing ahead of the feature in southern
Manitoba/adjacent northern Ontario, so not out of the question that
there could be isold aftn shra. On the other hand, prevailing
gradient northerly flow will essentially eliminate lake breeze
convergence as a low-level forcing mechanism unless lake breeze off
Lake MI can develop. So for now, left any mention of pcpn out of
fcst. Expect highs ranging from around 70F along Lake Superior to
well into the 80s inland.
On another note, satellite imagery, especially MODIS/AQUA imagery,
shows a very thick layer of wildfire smoke extending from ND ne
into northern Ontario. Unfortunately, this band of smoke will
likely move across the area on Fri. The smoke will be much
thicker than anything experienced this summer.
.LONG TERM...(Friday night through Thursday)
Issued at 340 PM EDT THU AUG 16 2018
Rather quiet start to the extended forecast, with a weak mid-lvl
trough axis departing the Great Lakes region late Sat. Closer to the
surface an elongated surface ridge will continue to provide dry
condtiions to the area through Sat, but heading into the second half
of the weekend with the surface ridge departing to the east. Some of
the guidance is starting to slow the departing surface ridge until
later Sun, which could further delay clouds returning and precip
chances until Mon.
A frontal boundary continues to be progged by guidance for
approaching from the west/northwest early Mon, with a shortwave
developing across the Central Plains early in the week. This
shortwave is being progged to lift northeast towards Lower Michigan
Tue/Wed with a wide precip shield accompanying this low pressure
system. This should increase chances for showers/thunderstorms
Tue/Wed of next week.
Temperatures will steadily warm and become more humid over the
second half of the weekend, with highs in the upper 70s to middle
80s. Mild overnight temps are also expected as cloud cover is not
going to dissipate, keeping lows in the 60s for the bulk of the
extended. With the system arriving Tue/Wed, this should provide
cooler temps with rainfall with highs back into the upper 60s to
lower 70s for many areas then warming yet again later in the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 630 PM EDT THU AUG 16 2018
VFR conditions are likely to prevail at KIWD/KCMX/KSAW thru this
fcst period. Could be some fog for brief times at IWD overnight and
at SAW late tonight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 421 PM EDT THU AUG 16 2018
Winds across Lake Superior will be under 15kt thru Sun. However,
high pres building over northern Ontario on Fri may lead to ne wind
gusts of 15-20kt over western Lake Superior. A vigorous low pres
system for Aug is expected to track ne into the Great Lakes region
late Mon/Tue. This system will bring northerly winds of at least 15-
25kt with gusts to 30kt.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Beachler
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service New York NY
1036 PM EDT Thu Aug 16 2018
.SYNOPSIS...
High pressure will remain off the southeastern coast as a warm
front moves into upstate New York and into central New England
overnight. Meanwhile, low pressure across the eastern Great
Lakes will bring a cold front toward the region Friday and
Friday night. The cold front will be moving into the region
Saturday, and then southeast of Long Island, but with some weak
lows forming along it Saturday night. The low pressure along
the front and front itself will linger offshore for Sunday into
Sunday night. High pressure from the Canadian Maritimes will
build in Monday into Tuesday next week. A frontal system
approaches the region for the middle of next week and exiting
the area next Thursday.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
Updated winds, gusts, temperatures, dew points, and sky grids
for current conditions and overnight trends. Both the
temperatures and dew points were in generally on track, with
some area slightly warmer than forecast. With increased cloud
cover and the warm and humid airmass in place, temperatures,
especially along the coast, are not expected to reach the
previously forecast lows and raised overnight lows a couple of
degrees.
High pressure centered off the southeastern coast
remains in place overnight. Meanwhile,a nearly stationary
frontal boundary across northern Connecticut into upstate New
York will move north as a warm front, maintaining a warm and
humid airmass across the region. A mid and upper level ridge
will slide slowly to the east as a shortwave rides along the
frontal boundary through upstate New York. The area will remain
dry, however, some showers and thunderstorms may develop toward
morning into the mid Hudson Valley region.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
With the 00Z NAM showing a slower trend in the shortwave riding
along the warm frontal boundary lifting into upstate NY delayed
the onset of precipitation and cut back on the areal extent of
the precipitation probabilities through Friday morning. Looking
to be closer to 15Z to 16Z before any precipitation arrives.
Even the latest HRRR is keeping the precipitation north of
Orange and Putnam counties.
The mid and upper level ridge move into the western Atlantic
Friday as a shortwave trough, amplifying slightly, moves into
the Great Lakes by 00Z Saturday. The mid and upper flow will be
nearly parallel to a cold front which will move little during
the day. Daytime heating should be sufficient to produce
instability, especially inland, and a pre-frontal trough will
provide focus for the development of thunderstorms. Some of the
storms may become strong with gusty winds and potentially
damaging winds across portions of the lower Hudson Valley and
into southwestern Connecticut. Added some enhanced wording of
gusty winds in these areas for the afternoon and into early
Friday evening. Also highlighted this in the Hazardous Weather
Outlook, HWOOKX.
Clouds increase Friday morning with showers and thunderstorms
becoming more likely Friday afternoon and evening mainly across
the interior, as a cold front nears the area. Localized flooding
will also be a threat with any strong thunderstorms.
Temperatures Friday will be in the mid to upper 80s to near 90.
The combination of warm temperatures and a southerly flow will
allow dew points to climb into the 70s. This will result in heat
indices in the lower to mid 90s, with some upper 90s in
northeastern New Jersey, across the advisory area. Most areas
did not reach the minimum of 95 heat indices Thursday afternoon.
However, will continue the heat advisory for Friday until 22Z.
There is a moderate risk for the development of rip currents at
the Atlantic ocean beaches Friday.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
The region remains on the backside of an upper level trough
with mid to upper level WSW flow. The cold front will move into
the region and with daytime heating Saturday as highs reach well
into the 80s, would expect scattered showers and thunderstorms
to develop. The showers and thunderstorms will still be capable
or producing heavy rain with PWATS being near 2 inches,
characterizing a very humid airmass. The showers and
thunderstorms could very well linger into the evening Saturday
along the coast as there are some small areas of low pressure
forecast to develop along the front, which will decelerate its
forward movement to the southeast. Mid and upper level flow
remain out of the SW too, so the steering flow would halt the
progress of the front as well.
The front eventually is expected to move far enough offshore
Sunday and with a pressure gradient between the low southeast
and an approaching high to the Canadian Maritimes, more of a NE
flow is expected to develop. The high pressure area eventually
settles into the Canadian Maritimes, prolonging the NE flow to
close out the weekend and into early next week. This will
promote a relatively cooler and a little less humid airmass with
highs in the upper 70s to near 80 and lows in the low to upper
60s. However, clouds could linger much of the time along the
coast, especially Eastern Long Island. There is a lingering
chance of showers Sunday for the whole region and a slight
chance of them Sunday night along the coast. Thunderstorms are
not expected Sunday and Sunday night with more stable air in the
region.
The airmass starts to warm again with decreasing NE flow and
more sun Monday and Tuesday. Shower and thunderstorm chances
return towards midweek period with the next frontal system
approaching. Airmass will continue to warm with highs more in
the low to mid 80s forecast for Wednesday.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
A cold front will slowly approach from the west through Friday.
Winds diminish tonight, then strengthen from the S-SW on Fri.
Cut back on speeds compared to the previous forecast except
right along the coast, and it now appears that the sea breeze
should make it to KEWR/KTEB after 18Z. Could see a few showers
and maybe a stray tstm near KEWR/KTEB between 18Z-21Z, with the
main push of activity with the approaching front arriving late
day or early evening.
.OUTLOOK FOR 00Z SATURDAY THROUGH TUESDAY...
.Fri night...MVFR or lower conditions likely in showers/tstms,
especially before 04Z Sat.
.Sat...MVFR or lower conds at times in any showers/tstms. W flow
becoming NE Sat eve.
.Sun...Chance of MVFR cigs in the morning.
.Mon...VFR.
.Tue...Chance of MVFR cigs.
&&
.MARINE...
Winds and seas forecast remain as forecast with no changes at
this time.
Ocean seas remain below SCA conditions through Friday then
slowly build to SCA levels by Friday night ahead of a frontal
boundary.
A brief period of sub-SCA conditions for all waters Saturday through
much of Saturday night will be followed by increased NE flow
increasing the easterly fetch and swell behind the cold front with
increasing chances for SCA conditions on the ocean starting late
Saturday night. The forecast has this increase in NE flow leading to
more swell and increasing ocean seas up to 5 ft and forecast wind
gusts on the ocean increasing up to 25 kt late Saturday night
through Sunday. The SCA ocean seas will remain probable Sunday night
and into Monday and Monday night for eastern ocean waters while
winds are expected to remain below SCA. All waters are forecast to
remain below SCA late Monday night through Tuesday night.
&&
.HYDROLOGY...
Heavy tstms late Friday through Friday night could result in
minor urban flooding. Thunderstorms Saturday could still
produce some locally torrential downpours with a marginal threat
for flooding, mainly minor. Otherwise, no significant
widespread rainfall is expected.
&&
.EQUIPMENT...
NYC NOAA Weather Radio Station KWO-35 (162.55 MHz) remains off
the air for an extended period of time.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Heat Advisory until 6 PM EDT Friday for NYZ071>075-176>179.
NJ...Heat Advisory until 6 PM EDT Friday for NJZ006-104-106>108.
MARINE...None.
&&
$$
SYNOPSIS...Fig/JM
NEAR TERM...Fig/19
SHORT TERM...Fig/19
LONG TERM...JM
AVIATION...Goodman
MARINE...Fig/JM/19
HYDROLOGY...Fig/JM
EQUIPMENT...
Area Forecast Discussion
National Weather Service Paducah KY
611 PM CDT Thu Aug 16 2018
.SHORT TERM...(Tonight through Saturday night)
Issued at 253 PM CDT Thu Aug 16 2018
Weak isolated convection on radar this afternoon driven by only
weak mid level support and instability. Not expecting much change
through the afternoon. The instability isn`t too shabby, so a
flare up storm possible, but isolated. Locally heavy rain,
perhaps. Not much change this evening. Overnight, as a mid level
s/wv trof approaches, forcing and instability should result in an
uptick in convection, especially after midnight through sunrise.
How coverage will play out is still uncertain, as the CAM`s models
continue to be of little help, typical in this kind of regime.
Energy associated with the trof will be slow to shift east
Friday. A weak front will move into the area late Friday and
Friday night. Good chance PoPs for convection as a result, with
strong storms and locally heavy rainfall possible. PoPs will taper
off from NW to SE late Friday night through Saturday. Expect some
diurnal enhancement during the day Saturday with heating given the
close proximity of the upper system, especially west KY. We should
dry out Saturday night. For the short term, basically used a
blend of the EC/GFS and NAM, smoothing out the details, accounting
for uncertainty. Temps were derived from the NBM and previous
forecast numbers.
.LONG TERM...(Sunday through Thursday)
Issued at 253 PM CDT Thu Aug 16 2018
Sunday continues to look mainly dry as an upper level ridge builds
in over the area. Meanwhile our next weather maker will be slowly
moving east across the country`s mid section. Although there
continues to be some timing differences, there is enough consensus
now to believe parts of southeast Missouri will see at least a
chance for rain as early as Sunday evening as the system nears.
Showers and storms will surge eastward overnight on Sunday and into
Monday morning as this warm front continues pushing northward. How
far east and north the precipitation reaches before 12Z Monday is
still questionable but it looks like most of southwest Indiana and
even the Pennyrile region of west Kentucky will be dry prior to 7am
Monday with the latest GFS/GFS ensembles actually providing the
slower solutions. Nonetheless, will indicate a tight POP gradient
with likely POPs far west to slight chance or no POP east.
During the day on Monday, we will see periods of showers and storms
as the upper system moves into the area and more than one upper
level shortwave may swing through. The rain should taper off from
west to east Monday night. PWs will surge back to 2+ inches with
this system so heavy rainfall is possible with the individual cells.
We could see a brief respite from the rain on Tuesday but another
quick moving upper trough will arrive from the northwest and
impact the area Tuesday night into Wednesday, bringing another
small chance for rain. Models are actually in pretty good
agreement on the timing of this as well.
In addition, the cold front will actually pass through the area
Tuesday/Tuesday evening. In the wake of the front, much drier and
cooler air will infiltrate the area as high pressure slowly builds
in. Highs will be in the lower 80s Tuesday through Thursday with
lows in the lower 60s, possibly even upper 50s in some locations.
Dry weather will continue through at least the end of the week.
&&
.AVIATION...
Issued at 610 PM CDT Thu Aug 16 2018
For the most part, convective activity should remain out of the
WFO PAH TAF locations for the 00z Friday issuance. However, given
the proximity of towering cumulus and isolated showers near KOWB,
left an evening mention of vicinity thunderstorms for this
particular location.
Prefer the NAMNest ensemble and 13km RAP guidance for
initialization of the TAF`s. They both keep the best chances for
convection and MVFR ceilings until after the 07z-09z time frame,
in line with the expected arrival of overnight convection from
Missouri and Illinois. Also prefer the lower VFR/upper MVFR
ceilings during the morning, then the development of afternoon
convection.
Favored mention of vicinity convection over explicit convection,
given the very poor timing and placement of the showers and
thunderstorms by the high resolution/medium range guidance this
afternoon.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
AVIATION...Smith
Area Forecast Discussion
National Weather Service Portland OR
305 PM PDT Thu Aug 16 2018
.SYNOPSIS...Some isolated thunderstorms are possible over the Oregon
Cascades and Coast Range this afternoon and evening as an upper
level trough approaches the region. The trough will increase the
onshore winds and push marine clouds inland Friday morning for
cooler afternoon temperatures inland. Haze and air quality will
gradually improve over the next 12 to 24 hours with some blue skies
possible Friday afternoon. High pressure returns this weekend for
less morning clouds inland and warmer afternoon temperatures. Low
clouds will likely linger along the coast.
&&
.SHORT TERM...Tonight through Sunday....A weak upper level trough is
approaching the region this afternoon and will transit the area
tonight and Friday. There has been some light showers and even some
isolated thunderstorms over the elevated terrain today. The threat
for thunderstorms over the Cascades and Coast Range will continue
through the evening hours.
The onshore winds are a bit stronger today, which is helping improve
air quality over the region. Most of the air quality sensors have
improved into the moderate category with a few remaining in the
unhealthy category. There are even a couple sensors in the good
range this afternoon.
The marine layer will deepen tonight into Friday morning as
the weak upper trough moves inland. Thus, expect a cloudy start to
the day Friday with cooler afternoon temperatures inland. Occasional
drizzle is expected on the coast and west slopes of the coastal
mountains Fri morning due to lifting of the moist marine layer. The
clouds will clear Fri afternoon. The flow aloft becomes NW behind
the upper trough Friday afternoon which should clear the haze from
the wildfires. The HRRR smoke model depicts this quite well as the
smoke is advected to the east over the next 12 hours.
The upper level trough will move into the northern Rockies by Sat
morning with an upper level ridge moving into the Pacific Northwest.
This will bring pleasant weather for the upcoming weekend with inland
temperatures in the low to mid 80s and coastal temperatures in the
60s. An upper low will undercut this ridge and move over the
Pacific NW on Sunday, which may bring a slight chance of
thunderstorms to the southern Cascades late Sunday into Monday. The
upper low will result in the steering flow becoming southerly, which
could bring smoke into the region once again from the wildfires in
southern Oregon. /tw
.LONG TERM...Sunday night through Friday...Models are showing an
upper-level trough with a closed low approaching Sunday night and
sitting right over us on Monday. With most of the GEFS ensembles
also showing this feature in relatively the same place, this
increases confidence in this feature for Sunday night into Monday.
With the location of the closed low, the cooler air aloft with the
still fairly hot surface temperatures will help to destabilize the
atmosphere and could generate showers and perhaps a few
thunderstorms anywhere from the Coast Range east toward the Cascades
Monday afternoon and evening. The upper-level low retreats westward
offshore on Tuesday, which means southerly flow over the area and
maybe even some offshore surface winds on Tuesday. If surface winds
turn offshore, we may see Tuesday get hotter than Monday. By
Wednesday, the upper-level trough finally kicks through from the
southwest, which pattern-wise may suggest another shot at showers or
perhaps even thunderstorms, but the better chance will be north of
our area. Right now, holding off as the models aren`t showing any
showers on Wednesday, likely due to the track being farther north.
Later next week, flow starts to become more zonal, which should
bring back more seasonably normal temperatures. -McCoy
&&
.AVIATION...The widespread MVFR stratus across the region this
morning has now scattered out in most places. Expect widespread
VFR conditions through the rest of the afternoon. There are some
mid-level convective clouds showing up on satellite and radar
this afternoon. There is a slight chance that a couple of
thunderstorms will develop over the Cascades or Oregon Coast
Range later this afternoon or this evening. An upper level trough
will move onshore tonight, deepening the marine layer even more
than we saw last night. MVFR cigs to spread back onto the coast
by 03Z this evening. The deeper marine layer should allow for an
extensive marine stratus push into the interior going into Fri
morning, with widespread MVFR cigs expected to develop by 12Z-
14Z. MVFR cigs will likely last until around midday.
KPDX AND APPROACHES...VFR conditions continue through the rest of
today and much of tonight. MVFR stratus likely returns to the
terminal by 10Z-12Z and remains through most of tomorrow
morning. Pyle
&&
.MARINE...Expect little change to the overall weather pattern
through the first half of next week. High pressure will remain
over the NE Pac, while thermal low pressure remains over northern
California and southern Oregon. This will result in persistent
northerly winds over the coastal waters. The winds will become
gusty over PZZ255/PZZ275 during the afternoon and evening hours
each day through Saturday. A small craft advisory is in effect
for these zones today, with another one for tomorrow. Upper level
low pressure will approach later in the weekend and early next
week. This will weaken the NE Pac high, which should result in
lighter winds.
Winds will remain 5 to 7 ft through the end of the week, with
seas dominated by fresh NW swell with a period of 9 to 11
seconds. Seas drop down closer to 5 ft over the weekend. Pyle
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...Small Craft Advisory for winds from 2 PM this afternoon to 2 AM
PDT Friday for Coastal Waters from Cascade Head OR to
Florence OR out 60 NM.
&&
$$
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This discussion is for Northwest Oregon and Southwest Washington
from the Cascade crest to 60 nautical miles offshore. This area is
commonly referred to as the CWA or forecast area.