Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/17/18
Area Forecast Discussion
National Weather Service Binghamton NY
958 PM EDT Wed May 16 2018
.SYNOPSIS...
High pressure will move eastward across New England through the
later part of this week with a nearly stationary frontal
boundary to our south across the Mid-Atlantic brining shower
chances to mainly the Poconos. This front will lift northward
through the region on Saturday increasing rain chances across
the region by Friday night.
&&
.NEAR TERM /THROUGH THURSDAY/...
955 PM Update...
Forecast finessed in the very near term for temperatures and
location of showers, but overall things are already well on
track. Next wave is now moving in from Central PA as expected
and will sweep over Northeast PA to Sullivan County NY during
the next several hours. Expectations still as per discussed
below.
Previous discussion...
A frontal boundary south of the region will continue to very slowly
push southeast through the day Thursday. Several weak mid-level
shortwaves along the frontal boundary will lead to some showers
with the highest chance in the Poconos, closer to the actual
frontal boundary. Showers ongoing will depart the region for a
few hours early this evening before another round comes into the
Poconos and southern Catskills later in the evening. High
pressure to our northwest will limit the northward extent of the
rain, struggling to get north of the PA/NY line eastward into
Sullivan county. Fairly good agreement is present in this
outcome from the NAM/HRRR and RAP models. Lows tonight will
generally be in the mid 50`s staying warmer due to clouds.
Given mainly light winds, some fog is likely to form again
toward sunrise across the region. Low clouds and showers may
keep fog formation from occurring in the Poconos and southern
Catskills.
Our forecast leans a little pessimistic with clearing and fog
burning off in the morning tomorrow. The Southern Poconos and
Catskills may not clear much on Thursday given the front is not
too far away still. Northwest winds and drier flow will lead to
clearing by noontime across the remainder of the region. Winds
may increase to around 10 mph in the afternoon. high
temperatures should reach the mid and upper 70`s. QPF should
stay under a half an inch where showers occur.
&&
.SHORT TERM /THURSDAY NIGHT/...
The frontal boundary will start to creep slowly northward once
again leading to an increase in clouds and and some scattered
shower chances across the Poconos and Southern Catskills.
Northern portions of the region including Syracuse and Rome
look to stay mostly clear further away front the front. Lows
will be in the upper 40`s north to low and mid 50`s south. QPF
should stay under a half an inch where showers occur.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Complex weather scenario will result in unsettled and changeable
weather in the long term. Closed upper low over the lower Ohio
valley will drift slowly east as a rather large surface low sits
over northern New England. Stalled surface boundary off the mid
Atlantic coast will also try to lift north as the upper low
comes east. Showers over northeast PA Friday will make little
progress northward until Saturday when the upper low begins to
fill and sweep northeast. Canadian cold front will follow the
low on Sunday bringing occasional showers.
Broad upper trof settles in over the Northeast U.S. on Monday
with a few instability showers possible. Surface high pressure
drops in for Tuesday bringing drier air and fair weather.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Difficult aviation forecast tonight with low confidence most
places. Tight north-south moisture and cloud gradient will mean
mainly high ceiling VFR at KSYR-KRME with ceilings lowering
rapidly to MVFR and IFR further south. Alternate minimum
restrictions are likely from KELM-KITH and KAVP after 06Z.
Hoping there has been enough relative drying of the boundary
layer today at KSYR and KRME to limit potential for dense fog
formation beneath the partly cloudy skies. Forecast hints at fog
potential with a late night MVFR category tossed in.
Elsewhere...stratus generally stays put with light fog
developing overnight. Drizzle with visibility restrictions will
continue at KAVP, before another shot of rain develops for a few
hours before sunrise. On Thursday...high pressure strengthens
over Quebec, forcing drier air to surge southward. Looking for a
fairly rapid transition out of the gloomy grey ceilings to
widespread VFR no cig by early afternoon.
Outlook...
Thursday night...VFR. Patchy valley fog possible.
Friday through Monday...Restrictions possible in periods of
showers and thunderstorms.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...MWG
NEAR TERM...MDP/MWG
SHORT TERM...MWG
LONG TERM...DGM
AVIATION...JAB
Area Forecast Discussion
National Weather Service Bismarck ND
943 PM CDT Wed May 16 2018
.UPDATE...
Issued at 936 PM CDT Wed May 16 2018
Little change in thinking for the remainder of the overnight
regarding convection from the previous update. However, the trend
within the 00 UTC Hi-RES Window ARW/NMM and the 01 UTC HRRR is
for elevated convection to potentially develop late tonight across
the James River Valley into far south central North Dakota along
the stalled front with the arrival of the leading mid level
impulses and increasing precipitable water. Otherwise, uncertainty
remains high regarding the isolated to scattered elevated
convective scenario through the late night into Thursday morning.
UPDATE Issued at 710 PM CDT Wed May 16 2018
Convective potential overnight across western and central North
Dakota continues to have somewhat of low predictability.
What is most certain is isolated to scattered thunderstorms
entering southwest North Dakota late this evening from southeast
Montana. Thereafter, the evolution of elevated convection quickly
loses certainty as clearly evidenced by the varied CAM depictions
through the night through the 22 UTC HRRR. It would be plausible
that isolated to scattered thunderstorms would be more favored
later in the night and into Thursday morning as precipitable water
and mid level lapse rates increase, with leading impulses
propagating across the area. While severe weather is unlikely, the
threat is non- zero late tonight into Thursday morning as 850mb
CAPE increase to 800-1000 j/kg with increasing deep layer shear.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 243 PM CDT Wed May 16 2018
A quasi-stationary frontal boundary across northern North dakota
will become the focus for showers and thunderstorms across west
and central North Dakota beginning late tonight but becoming
more numerous l;ate thursday.
Instability looks to be sufficient to support isolated Severe
thunderstorms late Thursday afternoon.
This afternoon and evening will be mainly sunny. Will see some
increasing clouds west late tonight. Widely scattered showers or a
thunderstorm is possible by morning far west and south central.
The showers and thunderstorms will become more numerous in
Thursday, especially Thursday afternoon as a plume of higher
dewpoints advect northward in increasing southerly flow. Showers
will become likely across teh south central by late Thursday
afternoon with scattered Thunderstorms. Highs thursday from teh
mid 60s north to the mid 80s south central.
.LONG TERM...(Thursday night through Wednesday)
Issued at 243 PM CDT Wed May 16 2018
The threat for heavy rain and severe thunderstorms highlight
Thursday night and Friday.
Numerous showers and scattered Thunderstorms are expected
Thursday night into Friday with a marginal risk of of severe
thunderstorms with 0-6 km bulk shear marginally available and BL
Cape between 2 and three thousand. Another consideration will be
heavy rain potential. The precipitable water is nearing the 99th
percentile based on the 30 year NAEFS climatological forecast and
an east-west frontal boundary is in place, which is usually a
good precipitation producer for North Dakota. The heaviest
rainfall looks to be south central through the James River Valley.
We have started to highlight this in the weather story with a
half to 2 inches of rainfall possible. An isolated 2.5 to three
inch amount is not out of the question. At this time will not
highlight flooding concerns as the ground should be able to take
up the moisture and the Flash Flood guidance remains close to 3
inches in 6 hours.
Cooler weather will then be seen for the weekend and scattered
light frost will be a threat both Saturday morning north central
and Sunday morning southwest.
The remainder of the forecast period will se a gradual warming
trend with generally dry weather until Tuesday and wednesday with
widely scattered showers and thunderstorms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 936 PM CDT Wed May 16 2018
Isolated thunderstorms are possible across western and central
North Dakota tonight into Thursday morning. However, impacts to
any one terminal tonight into Thursday morning are highly
uncertain. Thunderstorm chances slowly increase through the day
Thursday across the area. Numerous thunderstorms are possible
beginning late Thursday afternoon into Thursday night. A few
thunderstorms could be severe across the southwest and south
central. IFR conditions in thunderstorms are likely. MVFR ceilings
will develop across northern North Dakota Thursday afternoon and
evening.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...PA
SHORT TERM...WAA
LONG TERM...WAA
AVIATION...PA
Area Forecast Discussion
National Weather Service Buffalo NY
1022 PM EDT Wed May 16 2018
.SYNOPSIS...
High pressure will maintain pleasant and dry weather across the area
through Friday. Some fog may develop again tonight through Thursday
morning, especially along the south shore of Lake Ontario and in the
Southern Tier valleys. Periods of rain showers will return Friday
night into the weekend as a weak low pressure system moves across
the region.
&&
.NEAR TERM /THROUGH THURSDAY/...
A narrow ridge of surface high pressure across the eastern Great
Lakes will maintain tranquil weather across the region tonight. An
extensive area of cirrus to the north of a large upper level low
over the southeast states will continue to cross the region at times
overnight. Most of this will remain thin, although there will be
some thicker and lower clouds at times from the western Southern
Tier through the western Finger Lakes to the Tug Hill region. Expect
lows in the mid 50s in most locations, with lower 50s for the North
Country.
Fog development will again be a concern tonight into Thursday
morning from two different processes. Satellite imagery this evening
shows some marine layer fog just offshore in Lake Ontario west of
Rochester. The stagnant pattern and high resolution models such as
the HRRR and NAM-ARW suggest this fog will expand over Lake Ontario
overnight, and likely begin to impact the immediate shoreline. Very
late tonight and Thursday morning northerly winds will begin to
increase over Lake Ontario as a weak cold front crosses the lake.
This may push the marine layer fog onshore along much of the south
shore of Lake Ontario for several hours Thursday morning. Some fog
may also develop along the Lake Erie shore very late tonight and
Thursday morning. In addition to the marine layer fog, some fog will
develop in the Southern Tier valleys as well overnight from
radiational cooling processes.
On Thursday a weak backdoor cold front will drop south across the
region as a stronger area of high pressure builds into Quebec. The
passage of the cold front will help to push clouds associated with
the southeast states closed low away from the area, with a good
amount of sunshine in most locations. Some diurnal cumulus will
develop during the midday and afternoon along and inland of the lake
breeze boundaries. Expect highs to range from upper 60s across the
North Country to the low to mid 70s for the Thruway corridor, and
mid to upper 70s for the Southern Tier. Increasing northeast winds
will keep the south shore of Lake Ontario much cooler.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/...
Canadian high pressure over Quebec will maintain dry conditions
Thursday night, despite a reinforcing cool front settling south
through the region early Thursday night. The high will actually
strengthen as it shifts toward New England behind the front,
therefore expect clear skies. Clear skies combined with the
incoming cooler airmass will result in a cool night with
overnight lows ranging from the lower 40s across the North
Country to around 50 degrees across portions of the Southern
Tier.
The high will continue its track to the southeast through New
England Friday continuing to keep our region dry, although there
looks to be a low risk for a few showers sneaking into the Southern
Tier very late in the day, as some moisture begins to return
northward around the high. Otherwise, most areas should experience
sunshine filtered through increasing amounts of cirrus. Despite the
filtered sunshine, Friday looks several degrees cooler than the mid
week period with highs only in the 60s.
The high will finally push off the New England coast Friday night.
This will allow the frontal boundary to our south to start working
its way back north as a warm front. Deeper tropical moisture will be
sent northward as southern stream energy combined with this old
frontal boundary brings a large area of rain and showers into the
region starting Friday night with coverage becoming widespread
Saturday into Saturday night. Some locally heavy rainfall is not
out of the question considering the source region of the
incoming moisture feed. This may especially be the case Saturday
afternoon when some convective elements may develop in
enhanced/elevated instability.
&&
.LONG TERM /SUNDAY THROUGH WEDNESDAY/...
A plume of anomalously high moisture with PWATs of 1.25-1.5 inches
will be in the process of shifting east of the forecast area on
Sunday as a shortwave trough crosses New York into New England. This
shortwave will force a surface wave and trailing cold front to shift
across western and central NY which will keep a threat for scattered
showers to close out the weekend. Some of these showers may contain
some heavy downpours due to the elevated moisture plume exiting our
region. The showers may linger into Sunday night if the 12z EC is
correct while the 12z GFS shows mid-level ridging building in with
dry weather for Sunday night. Have continued to forecast chance POPs
Sunday and Sunday night with slight chance POPs on Monday due to the
difference in timing of the departure of the moisture axis and
supporting lift between the GFS and EC.
Monday night through Tuesday and Wednesday are still forecast to
bring broad Canadian high pressure building south across the Great
Lakes with a return to dry weather and sunshine. This is most
evident with the 12z EC while the 12z GFS and GEM models both show a
potential for more showers Monday night into Tuesday night with a
shallow wave and associated pool of mid-level moisture shifting
west-east across the Great Lakes. If later runs continue to show
this, then chance POPs may need to be added to the forecast early
next week. All global models show high pressure for Wednesday.
Temperatures look to remain above normal with with warmth provided
by a Bermuda High. Highs will reach toward the upper 60s to low 70s
each day and only slip back into the 50s each night. Dewpoints in
the 50s Sunday will keep a mild humidity level to our airmass to
close the weekend with a trend toward lower humidity moving into
next week.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR will prevail in most areas through most of the night with a deck
of cirrus level clouds crossing the region. One exception will be
from portions of the Southern Tier through the western Finger Lakes
to the southern Tug Hill region, where some MVFR to IFR CIGS will be
found.
Late tonight through Thursday morning fog will again develop over
Lakes Ontario and Erie, with some of this fog impacting shoreline
areas with IFR. Increasing northerly winds over Lake Ontario may
spread this fog inland off the lake for several hours from about 09Z-
14Z Thursday, with IFR becoming more widespread south of Lake
Ontario including KROC. Some valley fog will also develop later
tonight through early Thursday across the Southern Tier. If the fog
materializes, conditions may approach airfield minimums, with the
most likely impacted terminals being KROC and KJHW.
The fog will dissipate later Thursday morning. This will leave
mainly VFR for the rest of the day with thin cirrus level clouds and
some diurnal cumulus along and inland from the lake breeze
boundaries.
Outlook...
Friday...mainly VFR with a chance of showers across the Southern
Tier late.
Saturday and Sunday...Areas of MVFR with showers likely.
Monday...Mainly VFR with a chance of showers.
&&
.MARINE...
High pressure over the Central Great Lakes will expand across the
Lower Lakes through Thursday with light winds and minimal waves.
Areas of marine layer fog will continue on Lakes Erie and Ontario
tonight through early Thursday afternoon before a drier airmass
arrives and scours out the fog. Northeast winds will increase on
Friday, though conditions may remain just below small craft criteria.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Church/Hitchcock
NEAR TERM...Hitchcock
SHORT TERM...TMA
LONG TERM...Smith
AVIATION...Hitchcock
MARINE...Church/Hitchcock
Area Forecast Discussion
National Weather Service Charleston SC
1056 PM EDT Wed May 16 2018
.SYNOPSIS...
Low pressure to the southwest will bring unsettled weather to
the area through early next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
The MCS has continued to gradually shrink/weaken and with only
minimal instability we have shrunk the coverage of convection
early tonight. The best chances prior to 06Z will be over the
nearby Atlantic and north of Charleston, maybe scraping parts of
the South Carolina coast. Since the atmosphere is so worked over
across Georgia we are not sure how much of the activity south of
the Altamaha River will make its way into the forecast area, so
our PoPs lean conservatively. Late night convection could reform
in proximity to a wave inland far inland, isentropic ascent and
coastal convergence, plus aided by a short wave and upper
difluence. We did trim low temps down a few degrees from earlier
to account for rain-cooled conditions in many locations.
Probably too much mixing to allow for fog overnight, instead
stratus is more likely. But if the convective debris clouds thin
enough than some fog could occur where it rained earlier. Up to
1/4 inch of inch of rain will fall on the wildfire in northern
Charleston County, but not sure if it`ll be enough to completely
dose the fire, so a Dense Smoke Advisory remains in effect.
Previous discussion...
The ongoing MCS continues to gain momentum further north and we
have increased coverage of convection to account for the
activity definitely reaching the Beaufort area, and now most
likely the Charleston area.
At 748 pm...
We have realigned the best coverage of convection to account for
numerous to widespread activity south of I-16 that will
continue to advance north as per the HRRR through the mid
evening hours, impacting such communities as Hinesville,
Savannah, Springfield, Hilton Head and maybe Beaufort. This is
in association with an MCS that is found in a region of high
PWat, plenty of low level moisture convergence and moisture
transport, aided by upper difluence and H7-H4 DPVA. Not yet sure
if the activity will reach the Charleston area, so have been
more conservative on PoP that far north early tonight. Nothing
severe is expected, although wind gusts of 30-40 mph can occur
along the leading edge.
Dense Smoke Advisory remains in effect due to a wildfire in far
northern Charleston County. An earlier report from social media
indicated that visibility was significantly reduced in that area
north of McClellanville.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Thursday: An onshore flow will help maintain a moist airmass with
PWATs that approach 1.75-2.00 inches over much of Southeast South
Carolina and Southeast Georgia. Convective activity will likely
spawn early, becoming greater in coverage during afternoon hours as
sfc temps warm into the low/mid 80s and SBCAPE approaches 1500-2000
J/kg. Greatest precip coverage should occur over inland areas,
starting in Southeast Georgia during the morning, then spreading
north/northeast into Southeast South Carolina as a sfc low tracks
over/near the area ahead of a broad mid/upper lvl trough situated to
the west. Although severe weather is not anticipated, a strong
thunderstorm or two can not be ruled out during the day. The main
issue will be shower and thunderstorm activity potentially enhancing
a risk of coastal flooding during the high tide cycle late.
Otherwise, expect precip activity to diminish during the overnight
period as the sfc low continue to lift north of the region.
Overnight lows should range in the upper 60s to lower 70s.
Friday and Saturday: A fair amount of uncertainty remains in the
forecast over the weekend in regards to convection each day. At this
time, overall precip coverage appears slightly less as the Atlantic
high makes a subtle shift east and the swath of greatest PWATs
shift closer to the coast and offshore. This should reduce overall
convection over Southeast Georgia on Friday, before the Atlantic
high builds west and moisture returns over areas away from the coast
on Saturday. Given the setup, greatest shower and thunderstorm
coverage should occur near the coast and Tri-County area Friday and
Saturday, but an increasing trend over inland areas is possible by
Saturday evening. High temps should peak in the low/mid 80s away
from the immediate coast, warmest in Southeast Georgia each day.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Poor run-to-run model consistency yields low confidence in the
extended. There is moderate agreement that Sunday could feature
greater shower and tstm coverage due to upper vort energy in
place. Otherwise, we have trended toward the ECMWF with a building
Atlantic ridge and more typical diurnal convection.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
KSAV: Not yet sure if additional SHRA will move back into the
area overnight into Thursday morning. But due to a wave of low
pressure inland to the west, and energy in the mid and upper
atmosphere we have included VCSH since the atmosphere is
exceptionally moist and weakly unstable. Moderate confidence on
MVFR or maybe IFR ceilings late tonight into Thursday morning
if mid and high level clouds thin out enough, resulting from the
wet grounds and an abundance of moisture in the boundary layer.
There is a decent enough chance of TSRA along the sea breeze
and other meso-scale boundaries Thursday afternoon to include
VCTS as of this time, but flight restrictions are likely.
KCHS: Lingering SHRA will move away early tonight, followed by
too much uncertainty regarding specific timing of convection at
the terminal thereafter. So for now we have nothing worse than
low-end VFR ceilings and VCSH with the latest TAF set. However,
at least periodic flight restrictions can occur at most any
time late tonight into Thursday.
Extended Aviation Outlook: Periods of MVFR cigs are likely at both
CHS and SAV terminals with showers and/or thunderstorms each day.
Occasional reductions in vsbys will also be possible should heavy
rainfall directly impact either terminal.
&&
.MARINE...
Overnight: the waters will remain in between the sub-tropical
ridge to the east and a wave of low pressure to the west. The
result will be for southerly winds of 10-15 kt, except for
higher gusts in showers and t-storms. Based on latest trends of
seas, we have backed off on the start time of the SCA for the
outer Georgia waters until 5 am.
Thursday through Monday: A south to southeast flow will continue
across the coastal waters through early next week as a ridge of high
pressure remains over the Atlantic and a broad/weak trough of low
pressure persists inland. A somewhat stronger flow is expected on
Thursday and Thursday night as a sfc low moves through central
Georgia, enhancing the pressure gradient. Although winds speeds
should remain at or below 20 kt, seas are expected to build to 6-7
ft, starting in offshore Georgia waters early Thursday, then in
northern South Carolina waters by Thursday evening. Given the setup,
a Small Craft Advisory is in effect for offshore Georgia waters
until Friday morning and should eventually need to include the
northern South Carolina waters. Elevated seas could persist into
much of the weekend before conditions improve by early next week.
&&
.TIDES/COASTAL FLOODING...
The evening high tides through Friday will already be running
high due to astronomical influences. Persistent onshore flow
could push levels to advisory threshold on one or more days,
thus requiring Coastal Flood Advisories.
&&
.CLIMATE...
The low at KCHS so far today has been 71 degrees. The record
high minimum temp for the date is 71 from 1991.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Dense Smoke Advisory until 10 AM EDT Thursday for SCZ050.
MARINE...Small Craft Advisory from 5 AM Thursday to 10 AM EDT Friday
for AMZ374.
&&
$$
NEAR TERM...
SHORT TERM...DPB
LONG TERM...JRL
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
CLIMATE...
Area Forecast Discussion
National Weather Service Dodge City KS
619 PM CDT Wed May 16 2018
...Updated for aviation discussion...
.SHORT TERM...(This afternoon through Thursday)
Issued at 1200 PM CDT Wed May 16 2018
Quiet across SW KS as of midday, with very few clouds. Even the
winds are light and variable, but a more sustained SE wind of
10-20 mph is expected to begin this aftennoon. Convective
potential through this evening is quite limited, and reduced all
pops to slight chance (20%) coverage. HRRR iterations keep
insisting on isolated convection near/SE of Dodge City late this
afternoon/early this evening. With dewpoints in the 50s and MLCAPE
of 500-1000 J/kg, this is entirely possible. But flow and
kinematics are weak and forcing is subtle at best; if something
does develop it will not have much of a lifespan. SPC removed
their 5% marginal wind/hail probability from SW KS, and we concur.
We are in the time of year that the average pop on any given
afternoon is 20-25% anyway, so it`s not like saying 20% chance of
rain means that much. With the weak moisture and instability a
cumulus field will develop at least, which will dissipate after
sunset.
Tonight...clear and quiet. Ridge axis builds overhead through
sunrise, for few clouds and a light SE wind prevailing. Low
temperatures Thursday morning in the upper 50s to lower 60s.
More interesting weather is expected on Thursday, especially
Thursday evening. Ridge axis overhead during the morning hours
will keep winds light and the sky generally clear. Strong SE winds
are expected after about noon, as return flow establishes strongly
ahead of slowly-moving closed low in Nevada. Models prog about
10 mb of mslp gradient across the CWA, with 994 mb leeside
cyclogenesis in eastern Colorado, with gusts near 35 mph on tap.
This will maintain moisture advection into SW KS, with surface
dewpoints holding in the 58-62 range all day, and force the
dryline to hold in eastern Colorado or near the KS/CO border. It
is along this convergence axis that scattered thunderstorms are
expected to develop by evening, mainly west of US highway 83.
Progged CAPE/shear will be sufficient to support at least a large
hail/damaging wind threat across the western zones into Thursday
evening. Various models also depict an embedded shortwave in the
developing SW flow aloft, that may serve as an efficient trigger
to focus convection during peak heating. SPC marginal 5% wind/hail
is clearly justified, and would support expanding the slight risk
category further into the NW zones. With the primary severe risk
expected on Friday, Thursday will be the "day before the day" and
we will have to monitor the severe risk Thursday evening
carefully. If a subtle jet max/shortwave ejects on the SE
periphery of the Nevada cyclone at the right time late Thursday,
some higher end severe potential would be possible. Otherwise,
strong SE winds and highs in the 80s for all zones.
.LONG TERM...(Thursday night through Wednesday)
Issued at 218 PM CDT Wed May 16 2018
...Severe weather potential Friday and Friday Night...
Focus of attention continues to be early in the long term period,
with a significant threat of severe thunderstorms Friday. Large
hail and tornadoes are possible.
At sunrise Friday, closed 567 dm upper low will be near Salt Lake
City, with SW flow aloft over SW KS. A strong low level jet will
keep S/SE winds elevated overnight, which will hold most locations
in the 60s Friday morning, and continue to deliver moisture from
the Gulf of Mexico. A large thunderstorm complex is expected to be
ongoing at 7 AM Friday over Nebraska. A weak surface low will be
near Baca county, Colorado; this cyclone will strengthen through
the day, ending up near Garden City by 7 pm.
12z ECMWF continues to paint a traditional severe weather setup
for SW KS Friday afternoon/evening, with a triple point (dryline-
stationary front intersection) likely in or very near the CWA. One
of the biggest concerns for limiting factors has revolved around
moisture quality east of the dryline Friday afternoon. ECMWF has
trended upward in this regard (65-66 across the eastern zones)
which favors CAPE in the 2-3k J/kg range centered on SW KS. With
the strong surface cyclone providing convergence, high confidence
that thunderstorms will develop in an unstable environment. Have
noted ECMWF EHI bullseyes are centered on the CWA, and have
noticed ECMWF has now increased the 500 mb flow to 45 kts Friday
afternoon and evening. Several CAMs are displaying convective
outbreaks centered on SW KS as well. All of this to say, have
increased pops over the model blend for the central/eastern zones
and continued to mention severe (large hail/damaging winds) in the
grids.
Cold front will race through, probably as soon as the storms end,
with gusty north winds ushering in cooler/drier air through the
weekend. Afternoon temperatures will be reduced to the pleasant
70s on Sunday with dry conditions returning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 610 PM CDT Wed May 16 2018
Southeast winds will persist through tonight around 5 to 10 kts
and then increase to 20-25 kts by 16-18z as a surface trough
develops in the lee of the Rockies. There is a small chance of
thunderstorms late tonight around KLBL but the chances were
too small to include in the TAF. Thunderstorm chances increase
after the end of the period as storms slowly move eastward from
the high plains toward KLBL and KGCK. These storms may or may not
make it to those sites before dissipating.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 60 86 63 90 / 20 20 40 30
GCK 59 85 61 89 / 20 30 40 20
EHA 59 89 60 91 / 20 40 30 10
LBL 62 88 64 93 / 20 60 60 20
HYS 59 85 64 84 / 20 10 30 30
P28 62 87 65 91 / 20 10 30 30
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Turner
LONG TERM...Turner
AVIATION...Finch
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
956 PM EDT Wed May 16 2018
.SYNOPSIS...
High pressure will continue offshore into the weekend. Tropical
moisture, associated with an area of low pressure along the
eastern Gulf Coast, will spread north bringing increasing
chances of shower and thunderstorms through the weekend.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 940 PM Wednesday...Restructured the PoPs a bit for the
overnight hours as activity has diminished a bit inland with
moderate showers gathering off the coast. Have high chance PoPs
inland with likely along the coast as high-resolution HRRR
continuing to show increased activity overnight and into the
early morning hours Thursday. Warm moist flow and cloud cover
will make for another muggy night with lows in the upper 60s to
lower 70s in all areas.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 340 PM Wednesday...Models generally support repeat of
today with scattered to broken showers/isolated tstms in the
morning, then main coverage inland and just along coast in
afternoon. Will continue 50-70 % POPs for period. Max temps from
near 80 coast to lower 80s inland.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 305 AM Wed...An extended period of wet and unsettled
weather is expected through the end of this week and into next
week. Periods of heavy rain and thunderstorms are likely as
tropical moisture feeds into the region. Temperatures will be
around normal with highs in the low to mid 80s.
Thursday night through Saturday...Strong feed of tropical
moisture will continue during this period with strong Bermuda
high offshore, and stationary upper level trough over the lower
Mississippi River Valley. Periods of heavy rain and
thunderstorms are expected each day as MUCAPEs reach 1500-2500
J/kg, and PWATs approach 2". The heaviest and most widespread
rain is expected to fall both Friday and Saturday, as the plume
of tropical moisture focuses over Eastern NC, with minor
flooding possible. Have likely PoPs Thursday, and mostly 70-75%
PoPs Friday and Saturday. Have categorical PoPs west of HWY 17
on Saturday, where/when the highest confidence exists of
widespread rain and thunderstorms. High temps through these days
will reach the low 80s inland, with upper 70s along the coast.
Lows will mild, mostly in the upper 60s to low 70s.
Sunday through Tuesday...Upper trough will weaken greatly by
Sunday, but will still help spark scattered showers and
thunderstorms. More of the same is expected Monday, and a sea
breeze may also aid convection development both days. A cold
front and broad longwave trough will approach on Tuesday, and
will continue the shower chances. High temps will be a bit
warmer, with low to mid 80s expected inland, and upper 70s to
low 80s likely near the coast. Low temps will again be mild,
mostly in the upper 60s to low 70s.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term /Through 00z Friday/...
As of 650 PM Wednesday...VFR conditions at all TAF sites as of
early evening, but high-resolution model trends continue to show
increased precipitation near the coast and will indicate several
hours of MVFR ceilings at KEWN and KOAJ, while KPGV and KISO
remain in the low-end of the VFR category. While vsbys may
briefly lower during heavier showers or embedded thunderstorms,
will continue with VFR vsbys. S/SW winds will continue at 10-15
knots with occasional gusts to 20 knots this evening.
Long Term /Thursday night through Sunday/...
As of 330 AM Wed...Periods of showers and thunderstorms are
expected through the weekend, which will contribute to sub-VFR
conditions at times. The wettest, and most unfavorable flying
days will be Friday and Saturday.
&&
.MARINE...
Short Term /through Thursday/...
As of 950 PM Wednesday...As has been the case the past couple of
nights, winds have diminished a bit by late evening after the
normal diurnal gustiness. Winds generally S/SW at 10-20 knots
with a few higher gusts around Oregon Inlet. Seas continue to be
slow to build, running 2-5 feet, but local NWPS/SWAN guidance
continues to indicate seas building to 6 feet or better later
tonight and Thursday morning. No changes to advisories or
current forecast at this time.
Long Term /Thursday night through Sunday/...
As of 330 AM Wed...Small craft conditions will exist across the
southern and central waters through most of the period, due to
prolonged southerly flow. Seas will be mostly 4-7 ft, with winds
out of the south 10-20 kts.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement from 8 AM EDT Thursday through
Thursday evening for NCZ095-098-103-104.
MARINE...Small Craft Advisory until 11 PM EDT Sunday for AMZ152-154.
Small Craft Advisory until 8 PM EDT Sunday for AMZ156-158.
&&
$$
SYNOPSIS...JBM
NEAR TERM...CTC
SHORT TERM...JBM
LONG TERM...SGK
AVIATION...CTC/JBM/SGK
MARINE...CTC/JBM/SGK
Area Forecast Discussion
National Weather Service Nashville TN
749 PM CDT Wed May 16 2018
.UPDATE...
FOR EVENING DISCUSSION.
&&
.DISCUSSION...
Showers and thunderstorms had diminished to almost none in Mid Tn as
of 7 PM CDT, but the good ol` HRRR has been suggesting some
redevelopment over the Nashville area. As of 740 PM, we are seeing
this new development begin over Antioch and Nolensville. If the
HRRR continues to be correct, showers and storms will continue to
expand around Nashville Metro over the next couple of hours along
a low level convergence zone, then diminish again before
midnight.
The forecast was recently freshened for hourly trends. Pops were
increased over Metro for the evening, then pops dropped to 20
percent late night for the entire area. Patchy fog will occur late
night, especially in areas that have or will receive downpours.
&&
.AVIATION...
00Z TAF DISCUSSION.
High dew points overnight will allow for patchy BR formation,
mainly after 06z. However, the rain that occurred today along the
Cumberland Plateau could lead to patchy fog development as early
as 03z at CSV. Visibilities in BR will be mainly MVFR, except at
CSV, where some periods of IFR are possible around daybreak.
Our weather pattern will remain relatively unchanged during the
forecast period. This means that a weak and broad area of low
pressure will persist along the central Gulf coast and across the
Tennessee Valley, keeping our Middle Tennessee atmosphere moist
and unstable. In the absence of daytime heating, we expect only
isolated SHRA/TSRA overnight. However, the possibility for
thunderstorms to impact area terminals will increase by Thursday
afternoon, as surface-based CAPEs rise to between 1500 and 3000
J/kg. Have generally gone with the mention of "VCTS" after 18z,
and a Prob30 for "4SM -TSRA" during the final four hours of the
forecast period.
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION......13
AVIATION........19
Area Forecast Discussion
National Weather Service Spokane WA
551 PM PDT Wed May 16 2018
.SYNOPSIS...
Chances for showers and thunderstorms will increase Today into
Thursday as a slow moving low pressure system enters the region.
Slow moving cells will have the potential to produce locally heavy
rain this evening into Thursday over the Idaho Panhandle. The
arrival of a cold front on Friday will produce breezy north winds
and cool temperatures down close to average. Fewer showers can be
expected for the weekend with a warming trend into the beginning
of next week.
&&
.DISCUSSION...
Tonight through Friday: High pressure responsible for the hot/dry
weather the past several days has moved east with increasing
moisture entering the region from the south.
Tonight and Thursday morning: A mid level low over Central Idaho
will move into western Montana tonight. Strong instability over
the region today with 2 PM analysis showing surface based CAPE of
1000-1800 J/KG from the Columbia Basin into the north Idaho
Panhandle and 400-1000 J/KG over SE WA into the Central Panhandle
Mountains. Three areas of convection on radar this
afternoon...one over the Idaho Palouse into the Clarkia area with
a second area over the Okanogan Highlands and NE WA Mountains. Yet
a third area with numerous cells over NW Montana. HRRR for the
past several runs indicate potential for outflow boundaries to
initiate new convection from these cells with increasing showers
and thunderstorms over the region into this evening. Already
seeing some indication of this from the storms near the Idaho
Palouse. These storms are slow moving and will be capable of
producing heavy rain...small hail...frequent lightning
strikes...and gusty winds. Small stream flooding or localized
flash flooding is also possible. Thunderstorms tonight should stay
mainly east of Omak and Moses Lake although a brief shower or
storm over the Cascades can not be ruled out. Storms should weaken
after sunset but enough elevated instability is present that
nocturnal thunderstorms may continue into the early overnight
hours over NE Washington into the north Idaho Panhandle. Moisture
wrapping around the back side of the low will result in bands of
rain over N Idaho into SE Washington overnight into Thursday
morning. Given the moisture rich environments moderate to heavy
rain is possible.
Thursday afternoon/evening: Cloud cover over North Idaho will
limit instability for a much cooler and wet day as rain lingers
over the area. Meanwhile a different story for the Okanogan
Highlands, NE WA Mountains, Cascades, and evening the Columbia
Basin and possibly the Spokane area. A mid level wave dropping out
of British Columbia will combine with the moisture rich
environment to produce numerous showers and scattered
thunderstorms initially over the northern mountains Thursday
afternoon before spreading south into the Columbia Basin Thursday
evening. Locally heavy rain will add to runoff going into the
already flooded rivers...while significant rises on small streams
are likely in areas with heavy rain.
Friday: The upper low lingers over the region for more showers.
Instability is less however which is good news for the ongoing
flooding as showers should be lighter in intensity. JW
&&
.AVIATION...
00Z TAFS: There are two areas of scattered thunderstorm activity:
one is up across the northeast mtns of WA into the northern ID
Panhandle moving in out of BC, Canada and the other area are
storms moving westward into the Central Panhandle Mtns out of
western MT. The HRRR model seems to be handling the convection
fairly well and shows this convection reaching the Spokane/Coeur
d`Alene corridor between 02-05Z. Storms will be capable of
torrential rainfall, small hail and gusty variable winds.
Lightning potential will decrease after 05Z with the convection
morphing into more of a stable line of light to moderate rainfall
overnight. Added moisture across extreme eastern WA and into the
ID Panhandle will result in low stratus with IFR/MVFR conditions
possible Thursday morning at KGEG, KSFF, KCOE, KPUW and KLWS. /SVH
&&
.HYDROLOGY...
Many of our swollen rivers are forecast to crest over the weekend
or early next week. The Okanogan River has the potential to have
the highest impacts with a secondary crest occurring this weekend
and remaining in Major Flood Stage through at least mid next week.
While the Kettle River is not expected to reach last week`s
crest, it will still reach Major Flood Stage and again surpass the
historic 1948 record.
The Pend Oreille River and lake will become our biggest problem
area by mid to late next week. Water moves slowly through Lake
Pend Oreille into the river below Albeni Falls, and we will likely
be dealing with high flows well into June.
Flood warnings continues for the following rivers:
Kettle River near Ferry above Curlew affecting Ferry County
Lake Pend Oreille at Hope affecting Bonner County
Methow River near Pateros affecting Okanogan County
Moyie River at Eastport affecting Boundary County
Okanogan River near Tonasket affecting Okanogan County
Pend Oreille River below Albeni Falls affecting Bonner and Pend
Oreille Counties
Similkameen River near Nighthawk affecting Okanogan County
Stehekin River at Stehekin affecting Chelan County
St Joe River at St Maries affecting Benewah County
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 55 67 51 64 49 71 / 60 60 60 40 20 10
Coeur d`Alene 55 63 50 62 46 71 / 70 60 60 40 20 10
Pullman 54 65 49 64 47 68 / 60 20 60 40 30 30
Lewiston 57 71 53 69 51 74 / 50 30 40 40 30 30
Colville 55 71 52 66 46 75 / 50 80 70 30 20 10
Sandpoint 52 60 49 61 44 69 / 70 80 60 50 20 10
Kellogg 50 59 46 59 43 67 / 80 80 50 50 20 10
Moses Lake 57 80 56 71 52 77 / 20 10 50 60 10 10
Wenatchee 58 77 55 69 55 74 / 10 10 60 70 20 10
Omak 58 80 55 69 51 75 / 10 30 60 30 20 10
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Paducah KY
642 PM CDT Wed May 16 2018
.UPDATE...
Issued at 642 PM CDT Wed May 16 2018
The AVIATION section has been updated for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Friday night)
Issued at 238 PM CDT Wed May 16 2018
Near severe/severe convective activity developing along the
Mississippi River around 215 pm this afternoon has multiple foci
at the surface and upper levels this afternoon. At the surface,
the LAPS data showing convection developing on theta-e axis arcing
up the Mississippi river to Paducah, then working back along
I-24/I-57 in extreme southern Illinois. Aloft, the new convection
is oriented along a southwest-northeast trough axis with some
stretching and deformation ongoing at this time and some
overturning of higher theta-e air. The ESRL HRRR and HRRR high
resolution convection allowing models appear to have a good handle
on this convection, albeit 1-2 hours slower than expected.
Most of this convection will generally diurnal in nature this
evening, with some maintenance of showers in and near the trough
axis aloft, which will be renewed as another area of low pressure
aloft moves east across Missouri overnight.
As the upper low converges and congeals over the Quad State region
around daybreak, shower and thunderstorm coverage should increase
over the WFO PAH forecast area, especially during the late morning
and early afternoon hours. Differential vorticity aloft, combined
with differential surface heating and boundary layer moisture
convergence, should ensure redevelopment of multi-cell storm
clusters around the area. For now, have kept the best chances for
rain over west Kentucky, southeast Illinois, and southwest Indiana
through the evening on Thursday. As the low and the upper trough
move east-northeast, rain chances will diminish, with ridging move
into the area from the west on Friday.
.LONG TERM...(Saturday through Wednesday)
Issued at 238 PM CDT Wed May 16 2018
Pattern will remain active in the long term. Favored a model
consensus. Should be a lull in the activity Saturday with mid level
s/wv ridging across the area. Once the ridge moves east, unsettled
southwest flow aloft and a warm sector regime Sunday will return the
chance of showers and storms. A front should enter the area Sunday
night and continue south through Monday, maintaining the chance of
convection. Little change Monday night through Wednesday, as the
front is forecast to weaken and stall across the area. This regime
is favorable for on and off convective chances. Temperatures are
forecast to remain above normal.
&&
.AVIATION...
Issued at 642 PM CDT Wed May 16 2018
This is primarily a convective forecast, with VFR conditions and
light northeast winds expected outside of convection. Isolated
SHRA/TSRA will be possible at KEVV and KCGI this evening, but most
of the activity will be over southern Illinois and farther west
in southeast Missouri. Farther southeast across the region, the
atmosphere appears to be rather stable this evening. An upper-
level disturbance over northwest Arkansas this evening may
eventually spread more convection over our region late tonight or
Thursday, but confidence in timing and location preclude
mentioning in the forecasts at this time.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...DRS
SHORT TERM...Smith
LONG TERM...CN
AVIATION...DRS
Area Forecast Discussion
National Weather Service Mount Holly NJ
911 PM EDT Wed May 16 2018
.SYNOPSIS...
As a front remains nearly stationary over the Mid-Atlantic through
late Friday, several weak low pressure systems will move across the
region. As this front dissipates, a cold front then moves through
the region later Sunday into Monday before stalling nearby Monday
night through Wednesday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Surface analysis this evening shows the stationary front just south
of the forecast area, stretching from lower Delmarva westward to
central VA to Ohio Valley. Meanwhile, a ridge axis from high
pressure over the Canadian Maritimes extends southwestward into
northern NJ and northeastern PA. Despite SWly steering flow aloft,
the surface boundary to our south will struggle to make much
progress northward tonight owing to light winds within the nocturnal
boundary layer.
Widespread, steady rain will continue along and north of the front
through much of the night with two exceptions: (1) Drier air from
high pressure ridging southwestward into the area will initially
hold off the steady rain for our far northern zones (north of I-78)
through at least midnight before the northern edge of the precip
shield eventually spreads northward and (2) showers may become more
scattered in coverage toward early morning across far southern
Delmarva zones. Hourly PoPs were updated accordingly.
There has been deeper convective elements embedded within the rather
stratiform precip shield just to our south thus far this evening.
This convective activity has the potential to make it into Delmarva
late this evening and far southeastern PA/southern NJ overnight as a
plume of higher theta-e air and elevated instability expands
northward. A slight chance of thunderstorms were added for our far
southern zones even though forecast soundings (from the HRRR, RAP
and NAMnest) are marginally supportive of thunder given skinny CAPE
profiles of 300-700 J/kg. The main impact from the instability will
be to enhance precip rates, possibly yielding isolated heavier
rainfall amounts of 1-2" from roughly Philadelphia, southward.
Temperatures should remain fairly steady through the night owing to
overcast cloud cover and a light E-NE wind. With the cloud cover
already in place and widespread rain, do not anticipate the fog from
becoming dense except along the ridge lines (which will basically be
in the base of the low stratus deck).
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
Steady rain is expected to persist through the morning and at
least through the first part of the afternoon from roughly
south of I-78 and north of Dover, DE. We should see an earlier
end to the precip across NE PA and NW NJ around midday with
drying conditions gradually expanding S-SE later in the
afternoon.
From roughly the Delaware Bay, southward, there is a potential
for some breaks in the cloud cover to develop by afternoon with
the warm front lifting northward. If this happens, there may be
enough instability to support isolated thunderstorms by mid to
late afternoon.
Highs may struggle to reach the 70s except across the far north
where breaks in the clouds are more likely and across central
Delmarva which could see the front lift slightly farther north
enough to be back in the warm sector.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
Summary...Flood Watch for much of the area Thursday evening through
Friday night. Rounds of showers including heavy rain keeping
temperatures down through late this week, then warming over the
weekend and early next week.
Synoptic Overview...A ridge remains parked over the western Atlantic
while some troughing slides from the Plains toward the Northeast. A
moisture conduit is in place through late this week with injection
of tropical moisture from the south. A little more of a trough may
slide across the Northeast late in the weekend and early next week,
pushing the western Atlantic ridge southward some. The pattern
evolution should result in cooler air transitioning to warmer next
week.
For Thursday night through Saturday...The potential for times of
heavy rain is increasing, especially Friday into Saturday. Our
region will continue to be situated between a ridge to the east-
southeast and a trough back across the Ohio and Tennessee Valley`s.
The trough is forecast to get closer to our area late Friday and
Saturday, and ahead of this feature are several focused areas of
short wave energy sliding northeastward. At the surface, a front is
forecast to be stalled mainly just to our south and this will serve
focus for some weak low pressure systems to move along. While the
short wave energy will serve focus for ascent at times, mid to upper
level flow increases especially Friday into Saturday. This will
assist in transporting deeper moisture into our area, with
precipitable water values around 2 inches. There will be some
initial low-level drier air from the north getting into our northern
zones, however this should be replaced as surging moisture overtakes
the area by late Friday.
This pattern will offer rounds of showers, some of which will
produce times of moderate to heavy rain. The more widespread heavier
rain looks to occur Friday into Saturday as the system aloft to our
west nears and a plume of higher precipitable water values become
focused into our area. Given the amount of moisture and rounds of
ascent will result in plenty of rainfall. A flood watch has been
issued for much of our area starting Thursday evening and going
through Friday night for now. More on this in the hydrology section
below.
The guidance overall does not show much in the way of instability,
especially since the airmass is forecast to be or become nearly
saturated in the vertical. However, some forecast soundings
especially for the southern half of the area Friday afternoon shows
enough elevated instability for the potential for some thunder. As a
result, we focused more of the thunder mention at this time (slight
chance of thunder). Any thunder that gets involved will result in
increased rainfall rates. Temperatures will remain on the cooler
side especially Friday, then some warming is expected to start on
Saturday as low pressure tracks to our west and brings a weakening
warm front northward.
For Sunday and Monday...As an upper-level trough shifts eastward
from the Great Lakes and upper Ohio Valley Sunday, surface low
pressure is forecast to track to our north. Its cold front swings
into our area later Sunday, however it may stall in our vicinity due
to the flow becoming more parallel to it and another surface low
develops on its tail end. While this should lower the precipitation
chances, a few showers or thunderstorms cannot be ruled out
especially in the afternoon and evening both days as much warmer
temperatures are expected.
For Tuesday and Wednesday...We will have to see how the timing goes
as we get closer, however the passage of a short wave trough should
drive surface low pressure nearby with an accompanying frontal zone
eventually getting pushed a little farther south. The overall flow
though may be westerly enough to keep the frontal zone closer to our
area. For now went with some mainly slight chance PoPs especially
across the southern half of the area. Temperatures should be knocked
back some given the nearby presence of a frontal zone and weak high
pressure sliding by to the north.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Rest of tonight...CIGs are generally IFR this evening but
should settle in the LIFR range later in the night. Steady light
rain expected. E-NE winds 4-8 kt.
Thursday...Will be starting the day IFR or LIFR depending on
the ceilings at day break. However, expect some improvement to
occur initially N/W of Phila terminal (e.g., ABE-RDG) and also
to the S/E (e.g., ACY-MIV) after 18Z. There is low confidence on
timing of improvement in CIGs or with how much conditions will
improve. Winds will be light and variable.
Outlook...
Thursday night and Friday...MVFR/IFR with rounds of showers and
perhaps a few thunderstorms.
Saturday and Sunday...MVFR/IFR conditions persist with showers,
however conditions may improve at least some during Sunday.
Monday...Sub-VFR conditions possible especially with any showers and
thunderstorms.
&&
.MARINE...
Winds and seas are expected to stay below SCA conditions today
and tonight. Some visibility restrictions are possible in rain
showers and mist through this period.
Outlook...
Thursday night...The conditions are anticipated to be below Small
Craft Advisory criteria.
Friday and Saturday...Increasing onshore winds and building seas are
expected. A Small Craft Advisory is looking likely for at least the
Atlantic coast water zones.
Sunday and Monday...The winds are anticipated to be below advisory
criteria, however seas may take much of Sunday to drop below 5
feet.
&&
.HYDROLOGY...
Numerous rounds of showers and thunderstorms will continue across
the region through the end of the week and into the weekend. Heavy
rainfall is possible during this period, with the heaviest rain
falling Thursday night through at least Friday night. As of this
afternoon, the heaviest rain is forecast along and south of the I-78
corridor.
The current forecast calls for 2-4 inches of rain between this
afternoon and Saturday. This does not include the rain that fell the
last few days. Up to three inches have already fallen across
portions of southern New Jersey and the Delmarva.
A variety of flooding types are all possible within the Flood Watch
we issued. First, low-lying and poor drainage flooding is the most
likely type of flooding to develop. Second, flash flooding will be
possible under the stronger thunderstorms. Flash flooding occurs
quicker than other types flooding due to the torrential rain
thunderstorms can produce in a short amount of time. Flash flooding
is most likely to occur across urban areas where rainfall runoff is
maximized and where small creek and stream respond quickly. The rain
has to go somewhere and it eventually leads to larger streams and
rivers. This is the third type of flooding possible across the Flood
Watch area. If you live across the Passaic, Raritan, and Rancocas
basins in New Jersey or the Neshaminy, Schuylkill, and Brandywine
basins across Pennsylvania and Delaware, keep an eye on later
forecasts. These forecasts, as well as all of our hydrologic
forecasts, can be accessed via our Advanced Hydrologic Prediction
Service website.
Tides are also expected to increase through the end of the week as
well. This could exacerbate flooding across those areas where fresh
water and tides meet.
&&
.TIDES/COASTAL FLOODING...
Observed tidal levels as we approach high tide along the NJ and
DE oceanfront this evening have increased to around 1/2 to 3/4
ft above astronomical prediction in response to the onshore
flow (albeit light winds). Many of the tidal forecast points
along the coast should reach their minor flood stage but Coastal
Flood Advisories were not issued with the expectation that
levels fall short of advisory criteria (0.3 ft above minor).
The latest total water level forecast with "ensemble" support from
various tidal models indicate that each high tide cycle through
Friday morning should remain below minor criteria. However, with
onshore flow forecast to strengthen during the day Friday, there is
a potential for a more widespread occurrence of minor coastal
flooding with the Friday evening/night high tide cycle.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch from Thursday evening through late Friday night
for PAZ060>062-070-071-101>106.
NJ...Flood Watch from Thursday evening through late Friday night
for NJZ007-009-010-012>027.
DE...Flood Watch from Thursday evening through late Friday night
for DEZ001>004.
MD...Flood Watch from Thursday evening through late Friday night
for MDZ008-012-015-019-020.
MARINE...None.
&&
$$
Synopsis...Gorse
Near Term...Klein
Short Term...Johnson/Klein
Long Term...Gorse
Aviation...Gorse/Johnson/Klein
Marine...Gorse/Johnson
Hydrology...Kruzdlo
Tides/Coastal Flooding...Klein
Area Forecast Discussion
National Weather Service Springfield MO
210 PM CDT Wed May 16 2018
.SHORT TERM...(This evening through Thursday)
Issued at 110 PM CDT Wed May 16 2018
A couple of small scale upper level disturbances: 1) Well
pronounced mcv over ne OK will drift ese and for the most part
convection with this system will stay near or just south of our
border (best chances in the near term are the far sw corner of
MO). Bears some watching with the HRRR keeping persistent weak
convection along the MO/AR border tonight. 2) Over far se NEB
drifting to the southeast moving into central and east central MO
Thu. This may be more of a player for our weather for Thu during
the peak heating part of the day afternoon/evening with the
chances for scattered showers/thunderstorms favoring the eastern
cwfa.
In the meantime for the the rest of today, some isolated pulse
convection will be possible but given the relatively low
pwats/moisture aloft we are not expecting severe storms.
.LONG TERM...(Friday through Wednesday)
Issued at 110 PM CDT Wed May 16 2018
Friday: The shortwave over MO Thu will exit off to the east with
weak 500mb height rises through the day. Can`t rule out some
isolated convection given the instability, but the best chance for
any convection will likely be over the far sw cwfa where overall
moisture will be higher with pwats just under 1.5 inches.
Saturday-Sunday: The upper level shortwave ridge will shift east
of the area but guidance is having trouble resolving small scale
features and the placement of a sfc cold front over/near the
area. The ECMWF moves a sfc front through Sat night/early Sunday
while the GFS holds this front back to the west. In general the
pattern favors an uptick in rain chances either way, but don`t
have a lot confidence in timing/placement of convection.
Monday-Wednesday: The upper ridge is suppressed to the south with
modest westerlies aloft. The GFS is far more bullish with precip
versus the ECMWF with more moisture in place. In general, our late
Spring type pattern looks to continue.
&&
.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1213 PM CDT Wed May 16 2018
KSGF/KJLN/KBBG tafs: A weak slow moving upper level disturbance
will kick off isolated to scattered showers and thunderstorms in
the near term. Some of this may persist well past 00z. Outside of
thunderstorms, some cumulus vfr or mvfr ceilings will be possible
over the next few hours with light winds.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...DSA
LONG TERM...DSA
AVIATION...DSA
Area Forecast Discussion
National Weather Service Shreveport LA
1014 PM CDT Wed May 16 2018
.UPDATE...
Widely scattered tstms developed after sunset along a swd movg
outflow boundary which moved across the LA/AR state line and into
extreme northern La. Westward development into extreme eastern TX.
HRRR indicating convection could redevelop well after midnight
across northcentral LA. Cooler outflow air across se Ok/sw AR may
begin to fog up after midnight as well, especially where rainfall
occurs. Have included 20 and 30 percent chances for much of the
area overnight, and included patchy fog for much of that area./07/
&&
.PREV DISCUSSION... /issued 707 PM CDT Wed May 16 2018/
AVIATION...
Aside from convective debris clouds at ktxk and keld, vfr skc
conditions can be expected thru the eve as limited cumulus across
area already diminishing. Ktxk will see vcnty tstms thru at least
17/01z as western edge of convective cluster moves se across
extreme sw AR. Stg tstms just north of keld may bring outflow
winds from north to keld thru 17/01z as well. Fog possible at keld
later tonight from air cooled outflow as well and locating of
boundary near 17/12z may result in brief fog development at klfk
as well. Winds becmg nw around 5 kts by 17/18z across area./07/
PREV DISCUSSION... /issued 409 PM CDT Wed May 16 2018/
SHORT TERM.../Tonight through Thursday night/
Partly cloudy skies and a range of mid to upper 80s at the coolest
with a handful of low 90s at most temperature wise. Our winds
have been very light with some calm sites this afternoon adding to
the heat. There is a weak frontal boundary which for now remains
stationary from Northeast Texas and on across all of South
Arkansas.
Aloft, light SW-NW flow is seen on our 88D VAD wind profiler in
the lower to mid levels. There is quite notably a very stout
little compact vort over Eastern Oklahoma seen well on the visible
satellite imagery and is clearly showing a nice spin edging
slowly toward Arkansas. Most of the shower and thunderstorm
activity at this time is just to our North over Arkasas. There are
a few isolated showers and thunderstorms peppered in central
Louisiana and Northeast Louisiana.
We can expect additional showers and thunderstorms to be cropping
up in the remaining afternoon heat and will likely slowly fade in
coverage after sunset. There will still be a chance for nocturnal
thunderstorm activity generally along and East of I-49. The GFS
is the most encouraging as the HRRR is similar as earlier today,
but has backed off a bit on coverage over the last few hourly
runs. The NW flow beefs up for Thursday as the mid level ridge
builds over Texas/Oklahoma and Kansas which will nudge the chance
for rain out of the cwa after tomorrow afternoon. /24/
LONG TERM.../Friday through Tuesday night/
Northwest flow aloft will prevail over the Four State region through
Friday night when an upper level low pressure closed low becomes an
open wave moving into the ridge aloft and transitioning the flow to
more Southwest. This will result in more isolated convection during
the early part of the weekend. However during the late part of the
weekend the broad upper trough over the Western parts of the
country will see a series of upper disturbances spreading into the
forecast area. Temperatures under the ridge into the weekend will be
rather warm and cool slightly into the work week as rain chances
will return for much of the first half of the week with drier
conditions for the mid to late week with ridge aloft
returning over the area. /06/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 69 90 68 94 / 30 20 0 10
MLU 69 89 69 93 / 30 20 10 30
DEQ 61 87 62 89 / 20 20 10 20
TXK 65 88 65 90 / 20 20 0 20
ELD 64 87 64 92 / 20 20 10 30
TYR 68 90 69 92 / 10 10 0 10
GGG 68 91 67 93 / 20 10 0 10
LFK 69 93 69 94 / 20 10 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$