Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/18/22
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
1001 PM CDT Sun Jul 17 2022
.UPDATE...
Issued at 1001 PM CDT Sun Jul 17 2022
Vigorous convection has progressed farther south over southeast
Manitoba and northwest Ontario over the past several hours and has
recently expanded farther west toward the Winnipeg area. Model
guidance and time of arrival tools suggest this activity will move
into north-central and northeast Minnesota after 06Z. There is
plenty of instability ahead of the storm complex and the 00Z INL
sounding featured 100 mb MLCAPE of nearly 3000 J/kg. There is a
fair amount of dry air aloft, so parcel ascent will be tempered a
bit with dry air entrainment. Steep low-level lapse rates and
DCAPE of around 1350 J/kg suggest a potential for gusty winds with
the storms. Damaging wind gusts cannot entirely be ruled out.
Looking upstream at the Dryden, ON radar reveals an outflow
boundary surging ahead of the storms from north of Kenora to north
of Dryden and arcing farther northeast toward Sioux Lookout. Will
need to monitor trends to see if this indicates the beginning of
a weakening trend.
Have updated PoPs and weather with this update to focus on the
storm complex to our north. Raised PoPs into the "chance" category
for areas most likely to see rain overnight. The next period of
concern will be the 12Z to 15Z timeframe. Several high-res models
are propagating the storm complex in Saskatchewan eastward and
may move into northern Minnesota during that time, if they hold
together. Given the heat dome over the Dakotas and western
Minnesota, this evolution seems to fit the typical "ring of fire"
pattern common in the Northern Plains and Canadian Prairies in
late July.
UPDATE Issued at 736 PM CDT Sun Jul 17 2022
Despite high-resolution models continuing to generate convection
in the Red River Valley, mid-level subsidence in the wake of a
shortwave and ahead of a vort max over northwest Minnesota and
southeast Manitoba continues to suppress convection. The two
exceptions are a cluster of storms near Winnipeg and a few failed
attempts at deep convection in northwest Ontario. Additional
storms were located farther north into western Manitoba and far
northwest Ontario.
Have slowed down the onset of precipitation along the Canadian
border with this update to better reflect trends and expectations.
I still think we`ll have a chance of showers and storms later
tonight, so didn`t want to go dry at this time. High-res guidance
brings remnants of the northern line of storms into the Arrowhead
around 09Z, which I can`t rule out.
Otherwise remainder of the forecast is unchanged.
&&
.DISCUSSION...(This evening through Saturday)
Issued at 400 PM CDT Sun Jul 17 2022
Summary: Very warm Monday and Tuesday with chances for
thunderstorms, some severe. A dry period is expected for most on
Thursday and Friday then showers/storms return for next weekend.
Isolated to scattered showers and thunderstorms continued late
this afternoon, most widespread over northern Wisconsin. A few
echoes have been detected as far west as northern Cass and western
Itasca Counties. We expect most of this activity to diminish with
loss of heating. Additional thunderstorms are possible later this
evening/overnight as a trough moves into the region. Several of
the CAMs have shown this occurring with the storms diving
southeast into the Northland. However, there has been little
evidence of these forming other than a bit further north toward
Lake Manitoba. We will carry lower POPs to account for their
possibility but confidence isn`t very high. Fog will be possible
tonight but at this time, widespread dense fog is not expected
other than closer to Lake Superior.
A frontal boundary will hang up near the International Border
Monday, remaining there into Tuesday. Guidance varies quite a bit
regarding the instability forecast over northern Minnesota near
the front with the RAP much higher with MLCAPE values around 3000
J/kg but it seems to high with surface dewpoints. The GFS/ECMWF
have lower values from 1300-2000 J/kg but differ in location. Deep
layer shear will be 40+ knots so there is a chance for severe
storms Monday afternoon/evening and SPC has northern Minnesota
under a marginal risk. Monday will also be very warm and we have
forecast highs from the mid-eighties to lower nineties. Heat
indices will be in the nineties to near one hundred for much of
the area. We lowered dewpoint values some as some of the guidance
suggests mixing may be greater. The GFS shows steeper low level
lapse rates and mixes with drier air aloft which would lead to
lower dewpoints.
A better chance for severe storms will exist on Tuesday as a
potent upper waves arrives driving a cold front through the
Northland. There are some questions on instability but at least a
corridor of higher CAPE is expected along and ahead of the cold
front and there will be plenty of deep layer shear for a severe
threat. Most of the Northland is under a risk for severe.
Showers/storms will linger Wednesday with highs closer to normal
values. Drier conditions are expected Thursday/Friday with chances
for showers/storms returning for the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 608 PM CDT Sun Jul 17 2022
Isolated showers and storms will continue into this evening, with
coverage and intensity decreasing with time. High-resolution
models, including the HRRR, suggest storms in Manitoba and
northwest Ontario may persist and eventually move into northern
Minnesota later tonight. Have shifted the timing of precip a
little later at INL and opted for VCSH. Storms are possible, but
will likely be isolated and relatively brief overnight. Will
likely handle with TEMPO thunder with later updates this evening,
once confidence in timing increases. Also added some IFR
visibility at HYR. They picked up more than an inch of rain this
afternoon and once skies clear tonight should see fog. With
generally weak forcing expected Monday, think we`ll see another
round of isolated storms during the afternoon. Since
predictability is low, opted for a dry forecast during that time
for now.
&&
.MARINE...
Issued at 400 PM CDT Sun Jul 17 2022
Onshore winds winds less than 15 knots will become southwest
overnight and remain southwest into Monday. Areas of fog, some
dense, are expected to become widespread later this evening and
a Dense Fog Advisory is in effect. It`s possible the southwest
winds may cause the fog to dissipate late tonight but winds are
not that strong so we hold onto it until 8 am. A few thunderstorms
are possible tonight, north and east of Silver Bay. More
thunderstorms will be possible on Monday into Monday night, some
of which could be strong to severe. Winds will become easterly
again Monday night and remain through Tuesday. Winds Tuesday will
be a bit stronger, 10 to around 15 knots with some higher gusts.
More thunderstorms are expected Tuesday into Tuesday night, some
of which could be severe.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 64 90 64 81 / 10 20 30 50
INL 64 85 64 83 / 30 30 40 80
BRD 68 93 72 89 / 10 10 40 30
HYR 62 92 69 90 / 10 10 20 40
ASX 63 94 64 87 / 10 20 20 40
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...Dense Fog Advisory until 8 AM CDT Monday for LSZ121-140>148-150.
&&
$$
UPDATE...Huyck
DISCUSSION...Melde
AVIATION...Huyck
MARINE...Melde
Area Forecast Discussion
National Weather Service Gray ME
1109 PM EDT Sun Jul 17 2022
.SYNOPSIS...
Humidity continues to build through the week with a few chances
for rain. Low pressure will pass through the region Monday,
with an additional cold front passing through Tuesday. High
pressure moves overhead Wednesday, with low pressure approaching
from the Great Lakes Thursday
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
1108 PM Update...Very little change to the going forecast this
evening. A warm and humid but dry night is in store along with
some patchy fog.
725 PM Update...Dry and very warm weather as of 23z except for
one lone shower in Cheshire County. Can`t rule out a few more
pop up showers over the course of the next 2 or 3 hours but the
vast majority of the region will be dry. Some fog may move into
the Midcoast over the next 1 to 2 hours.
Previously...
Convection across southern New Hampshire and extreme southwest
Maine will wane through the evening with the loss of heating.
Short wave ridging will slide over New England late tonight
into Monday morning bring a mostly precipitation free night.
Southwest flow will deepen late tonight with dew points climbing
into the mid to upper 60s south of the mountains by Monday
morning. Increasing dew points along with mostly clear skies
tonight will allow for patchy fog to develop after midnight with
the most likely spots being the CT River and northern valleys
along with shelter locations along the coastal plain,
particularly near the Mid Coast. The influx of moisture rich air
will lead to lows only bottoming out in the upper 60s across
southern NH to the mid 60s south of the mountains and upper 50s
across the far north.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
A compact short wave that is currently diving southeast across the
Midwest and will approach New England Monday from the eastern Great
Lakes. Continued deep SW flow ahead of this wave will draw an
anomously high PWAT air into New England with much of the area
seeing PWATs in the 1.75 to 2 inch range by Monday afternoon.
This short wave will go neutral to negative tilt as it crosses
the forecast area Monday night. This system will bring showers
with embedded thunderstorms to area starting Monday morning
across western New Hampshire spreading eastward through late
Monday into Tuesday morning. High PWATs combined with warm cloud
depths greater the 10kFT and tall skinny CAPE profiles will
bring the potential for periods of heavy downpours with showers
and embedded thunderstorms. The HREF does show at least some
probability of rainfall rates approaching 1 inch per hour with
the HRRR also showing hourly rates around 1 inch, although no
one location looks to experience these rates for more than an
hour. The WPC excessive rainfall outlook continues to put the
entire area in a marginal risk for flash flooding, which seems
reasonable given the potential heavy rainfall rates. However,
given the very dry antecedent conditions and 1 hour flash flood
guidance well over 2 inches, concerns for flash flooding are
low with much of the rainfall being more on the beneficial side
outside of some ponding of water in poor drainage areas.
Current QPF forecast has 0.75 to 1 inch along the coastal plain
with amounts of 1 to 1.5 inches across the foothills. In the
mountains towards the Canadian border amounts rang from 1.5 to
1.75 inches with the Whites seeing upwards of 2 inches.
There continues to be questions regarding the evolution of this
system and whether it will be baroclinic with a defined warm and
cold front versus a MCS or remnant MCS. This will have implications
for instability and strong to severe storms. If the consensus of
model solutions pan out with a defined warm front and cold front,
portions of southern NH and extreme SW Maine may become enveloped in
the warm sector. This scenario will allow for greater instability
and severe potential. SPC has shifted the marginal risk for severe
storms just to the SW of the forecast area due to the uncertainty of
instability with cloud cover and showers moving in tomorrow morning.
Still, models show clockwise turning hodographs becoming
elongated through Monday evening with 0-6 km bulk shear
approaching 55 kts. If enough instability is realized, storms
with rotating updrafts will become favorable bringing the threat
for strong to damaging winds. The 12Z HREF has actually shown a
slight uptick in updraft helicity tracks versus previous runs
so current thinking is that threat for severe storms cannot be
discounted across southern New Hampshire and extreme SW Maine at
the moment. The window for strong storms looks to be from mid
afternoon until around 10 PM.
The short wave axis will not cross the area until Tuesday morning
maintaining chances for showers and embedded thunder going
overnight. The potential for heaviest rain looks to end by midnight.
It will be a warm and very humid night with dew points remaining in
the upper 60s to low 70s with lows generally in the same range. This
will likely lead to areas of fog and patchy fog across much of the
area with greatest chances in northern valleys and the CT
valley.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Overview: An active weather pattern this week. Low pressure
will swing north of the area Tuesday, with a cold front
approaching the region in the afternoon. This will bring the
chance for some showers and thunderstorms. High pressure drifts
across Wednesday with dry conditions, before another low crosses
the northern Great Lakes region and moves towards the Northeast
Thursday with unsettled weather possible.
Details: While there will be many eyes on the sfc low as it
passes through the region Tuesday morning, there may be a second
show of convection come Tuesday afternoon as well as gusty
winds during the day. This will be spurred on as the exiting low
tugs a follow up cold front towards the NW International
Border. This is associated with low pressure across central
Quebec, and should approach by mid afternoon.
The thermodynamic environment could recover quickly following
the exiting low. Forecast soundings display drying air through
the column as NW flow follows up. Thus, think clouds should be
thin or thinning into early afternoon peak heating. Cold air
arriving aloft on the same flow should increase CAPE values with
low level lapse rates increasing, and mid levels also trending
conditionally unstable into mid afternoon.
More uncertainty resides with the best area of forcing and
shear. The greatest forcing would be along the sfc cold front as
it nears the ME and NH mountains, but just how strong will the
front be and how progressive? Additionally, low level 0-1km
shear appears abundant at 20-30 kts, with deeper shear to 6km
varying in strength through some runs (generally 30-40 kts).
This would strike a good balance with CAPE amounts around 1000
j/kg in some NAM and GFS runs.
Summary for all of this is to continue the chance of thunder
across much of the interior Tuesday afternoon, and watch for
potential enhanced wording. Mode, coverage, and avail moisture
will need to be refined in coming forecasts.
In addition, excellent mixing behind the low combined with a
tight pressure gradient will bring the chance for gusty winds,
potentially up to 35 mph, throughout Tuesday. Upper bound of
momentum transfer would reach into the swath of low level winds
as the sfc trough crosses the Gulf of Maine.
Wednesday features high pressure nosing into the region as both
lows take off to the northeast. The deformation zone should be
overhead come Wed evening, with another low cutting across the
northern Great Lakes. The biggest take away beside a return to
some drier conditions will be building heat. Temperatures will
climb into the mid to upper 80s for much of the region, with mid
90s possible in southern NH.
Next low arrives Thursday, with a cold front crossing the CWA.
This will bring another chance of thunderstorms, some possibly
strong to severe, into the area. Confidence is increased based
on the proximity of the low, and the abundant heat/moisture in
the region. Will continue to monitor timing of the front as this
still varies through the model suites. Timing would help
specify whether thunder threat is confined to a certain part of
the CWA, but for now will carry much of it, especially the
interior, with a chance for thunder.
Warm temperatures look to persist into the weekend, with a
chance of some rain showers into Friday and Saturday as the
aforementioned low pulls away.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
Short Term...Mainly VFR is expected tonight into Monday
morning, although valley fog will bring brief restrictions to
KLEB and KHIE. Low stratus an fog may also impact KRKD tonight.
Showers and embedded thunder cross the area Monday likely bring
flight restrictions to all terminals with the greatest potential
for TSRA across southern New Hampshire Monday afternoon and
evening. SHRA continue Monday night along with patchy fog likely
impacting most terminals with low cigs and reduced vsby.
Long Term...Gusty WSW winds, potentially up to 30 kts Tuesday.
-SHRA and TS possible during the afternoon with occasional MVFR.
Conditions trend VFR for Wednesday. Additional SHRA and TS
possible Thursday afternoon.
&&
.MARINE...
Short Term...Southerly flow increases Monday ahead of low
pressure that will bring showers and possibly thunderstorms over
the waters Monday evening. Winds and seas look to remain below
SCA thresholds Monday and will approach 25 kts Monday night.
Long Term...SCA may be needed Tuesday afternoon as low pressure
exits north with gusty WSW winds. High pressure moves over the
waters Wednesday, with another low pressure system approaching
the St. Lawrence Valley Thursday. Showers or thunderstorms will
be possible both Tuesday and Thursday afternoon.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
NEAR TERM...Ekster
SHORT TERM...Schroeter
LONG TERM...Cornwell
Area Forecast Discussion
National Weather Service Lincoln IL
739 PM CDT Sun Jul 17 2022
.SYNOPSIS...
Issued at 738 PM CDT Sun Jul 17 2022
While most of the scattered showers have faded for the night,
areas south of I-70 will see the threat persist past midnight. A
few showers and storms are possible Monday morning east of I-57 as
well. Otherwise, an extended period of dry weather is expected
much of this week. High temperatures will return to the 80s and
lower 90s, as humidity levels climb enough to bring the heat index
back over 100 degrees by Tuesday in some areas.
&&
.UPDATE...
Issued at 738 PM CDT Sun Jul 17 2022
Hefty rainfall amounts of 2-4 inches or more have occurred in
parts of southeast Illinois since midnight, but the rain has been
weakening some as it shifts south of highway 50. Currently
watching a few showers dropping southwest from Pontiac and also
south toward Galesburg, close to a wind shift in those areas.
However, these should be weakening over the next couple hours.
Rain chances were updated in these areas over the next 1-2 hours,
as well as some tweaking south of I-70 for the latest trends.
High-res models have continued to suggest some patches of fog late
in the night. Latest runs are more focused south of I-70 with the
excessive rainfall earlier, though the amount of clearing in that
area is still in question. However, they have been showing some
coverage in the northern CWA to varying degrees. Will keep the
mention of patchy fog going overnight and early Monday morning.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 310 PM CDT Sun Jul 17 2022
The stationary front that had been positioned across central IL
for the last 24 hours has finally started to shift southeast, and
was located near I-70 at 1930z/230pm. A weak sfc low was located
in northern IN at this same time. Visible satellite imagery shows
widespread cloud cover south of I-72, but clearing across west-
central IL could allow temps to rise to near 80 this afternoon.
Elsewhere, temps will remain in the 70s. A line of convection,
located south of I-70 at 1930z/230pm, continues to track
southeast, but limited airmass recovery after the morning rain has
kept the storms from strengthening considerably. Despite the low-
topped nature of these storms, they are still producing intense
rainfall rates, however, the progressive motion should limit any
flash flooding concerns, even in areas that received heavy rain
this morning.
In the post-frontal airmass, visible satellite shows scattered
cumulus pivoting counter-clockwise due to the influence of the low
pressure. While an isolated shower will remain possible in the
post- frontal airmass, most areas north of I-72 will stay dry for
the rest of the day. A few funnel clouds have been reported across
far northwest IN, and this corresponds with the location where
the RAP shows an area of sfc vorticity collocated with low-level
instability. While the better potential for funnels will be north
of I-80, the RAP does show this zone of low-level
vorticity/instability shifting southward into evening, and it
would not be a complete shock if there were reports of funnels in
our northern counties (areas north of I-74) before sfc heating is
lost. These types of funnels rarely reach the surface.
Tonight, high pressure will build over the Missouri River Valley,
and shift eastward into Missouri on Monday. High-res guidance is
latching onto the potential for patchy fog between midnight and
sunrise, but digging into the forecast soundings from various
models only about half of the soundings have sufficient moisture
for fog development. Added a mention of patchy fog into the
gridded forecast, but not overly confident in its development
tonight, and dense fog is not expected.
Following the frontal passage, winds will be light and northerly,
but without the widespread rain or cloud cover across the area,
high temperatures will actually rebound and be about 10 degrees
warmer than today, with seasonable highs in the mid 80s. There
will still be a few hundred J/kg of CAPE across eastern IL on Mon,
which could allow for a shower or two as daytime mixing occurs.
However, forecast soundings show a warm nose around 800mb that
could limit convective coverage, and most CAMs only depict
isolated showers.
&&
.LONG TERM...(Monday night through Sunday)
ISSUED AT 310 PM CDT Sun Jul 17 2022
The next system to watch is a compact shortwave that will round
the ridge and track across the norther Plains on Tues, reaching
the Great Lakes by Wed. Ahead of this wave, southerly flow will
advect warm, moist air northward, resulting in a muggy day on Tues
with high temps near 90F and afternoon dewpoints in the low 70s.
This will push maximum heat indices to around 100F, but conditions
are not currently expected to warrant a heat advisory.
Additionally, modest southerly winds around 10 mph will make it
feel slightly less oppressive than if the winds were calm.
Forecast soundings suggest gusts to around 20 mph along/west of
I-55. No precipitation is expected on Tues as the low-level WAA
leads to a very strong cap.
For Wed, guidance depicts a strong 993mb low pressure over the
Great Lakes, with a cold front draped southwestward through WI
into west- central IL. As the front moves across the CWA, there
will be a conditional threat of svr storms, as there will be ample
instability and sufficient mid-level flow provided by the upper
level wave to strengthen any convection. However, a strong cap
appears likely to stymie convective development. Even the NAM,
notorious for overdoing the low-level moisture content, struggles
to erode the cap by Wed afternoon, by which point the front is
already pushing into SE IL. All available guidance sources show
little in the way of development through 00z Thurs (7 PM Wed), and
it`s possible that even if development occurs the front will have
already exited our area. The environmental conditions warrant
keeping an eye on the svr potential, but at this time storms
appear unlikely and the gridded forecast was kept dry.
Following the frontal passage, it looks like it will be a breezy
Wed afternoon, with sustained WNW winds around 15 mph and gusts
to 25 mph. Temps are expected to return to the 80s on Thurs,
followed by a warming trend into the weekend as upper level
ridging expands eastward.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 621 PM CDT Sun Jul 17 2022
Main forecast concern will be for potential of IFR conditions
after 06Z, mainly over eastern Illinois. Latest guidance has been
developing some ceilings below 1000 feet associated with a
boundary slipping southward this evening. Recent rainfall in
eastern Illinois has been lighter, and cloud cover should linger
longer there, to prevent a widespread taking of visibilities,
though they should lower to a few miles. Right now, will only
mention the IFR conditions at KDEC/KCMI. Areas further northwest
will see some MVFR ceilings/visibilities at times late night.
Conditions should improve by mid morning Monday.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...Geelhart
SHORT TERM...Erwin
LONG TERM...Erwin
AVIATION...Geelhart
Area Forecast Discussion
National Weather Service North Platte NE
615 PM CDT Sun Jul 17 2022
.SHORT TERM...(This evening through Monday night)
Issued at 320 PM CDT Sun Jul 17 2022
The RAP model shows an 18C-20C h700mb thermal ridge building into
wrn Nebraska Monday afternoon. The warmest temperatures at that
level will be confined to the Panhandle and this is the result of
sfc low pressure across wrn SD. Highs of 105F or above are in place
across wrn Nebraska Monday. This forecast leans on the short term
model blend and the guidance blend, plus the previous forecast. The
forecast is a compromise between the warmer/faster GFS which tracks
the sfc across SD farther east and the slower/cooler HRRR and RAP
models which keep the low farther west.
A fairly sharp moisture gradient should set up across ncntl Nebraska
limiting highs east of highway 183 to the upper 90s. Heat indices
across both wrn and most of ncntl Nebraska should approach or exceed
100 degrees and a Heat Advisory is in place Monday afternoon and
early evening in both areas.
The CAMS show isolated high based thunderstorms developing late in
the afternoon and early Monday evening across wrn Nebraska. These
storms will likely be dry thunderstorms and a slight chance POP
continues in place across wrn Nebraska.
.LONG TERM...(Tuesday through Sunday)
Issued at 320 PM CDT Sun Jul 17 2022
A Pacific cold front moving through the Pacific Northwest this
afternoon will arrive in wrn and ncntl Nebraska during the day
Tuesday, most likely in the morning. Both the blended guidance and
deterministic model blend continue to show high temperatures in
the low 100s along and south of Interstate 80. This is unusually
warm for a post frontal environment but likely indicative of the
caliber of the heat wave affecting the region Monday.
Wednesday will be the cool day with highs in just the 90s across all
but swrn Nebraska where 100F is in place. The models show
temperatures aloft dipping to around 12C-13C. Thereafter,
temperatures aloft steadily rise to 15C-17C supporting highs in the
upper 90s to low 100s. Today`s models are a bit slower developing
the next significant heat wave. Next Saturday would appear the
hottest day.
No meaningful rainfall is expected during the next 7 days but the
models continue to show a fairly steady stream of upper level
moisture rotating through the Rockies and then east through parts of
SD and Nebraska. Moisture, focus and forcing are the ingredients for
rain. Unfortunately, the models show very little focus, i.e. a sfc
front or boundary. In fact, the hot spell of weather the next 7 days
is driven partly by the absence of any sort of strong sfc low
pressure moving through the nrn Plains which would send a cold front
into Nebraska.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 615 PM CDT Sun Jul 17 2022
VFR will continue through Monday afternoon for western and north
central Nebraska. The main aviation weather concern is regarding
wind for Monday. Southerly near surface winds strengthen through
the morning with gusts 25+ kts expected during the afternoon.
&&
.FIRE WEATHER...
Issued at 320 PM CDT Sun Jul 17 2022
Little or no rainfall is expected across wrn and ncntl Nebraska
during the next 7 days.
Intense daytime heating Monday will lower humidity to around 15
percent across parts of wrn Nebraska. Wind gusts to near 30 mph are
likely during the afternoon plus there is the potential for isolated
dry thunderstorms along and west of highway 61. A Fire Weather Watch
is in place Monday for areas west of highway 61. The watch and
eventual warning may include the upper Niobrara valley near and west
of Valentine.
Fire weather conditions will likely remain elevated across wrn
Nebraska Monday through Friday. The concern is humidity near or
below 20 percent each day with modest nighttime recovery to 50 or 60
percent.
&&
.CLIMATE...
Issued at 320 PM CDT Sun Jul 17 2022
North Platte...forecast 105 record 103
Valentine... forecast 107 record 105
Broken Bow... forecast 97 record 110
Imperial... forecast 105 record 110
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday afternoon through Monday evening
for NEZ204-210.
Heat Advisory from 1 PM CDT /noon MDT/ to 9 PM CDT /8 PM MDT/
Monday for NEZ004>010-022>027-035>038-056>059-069>071-094.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
FIRE WEATHER...CDC
CLIMATE...CDC
AREA FORECAST DISCUSSION
National Weather Service Morristown TN
928 PM EDT Sun Jul 17 2022
.UPDATE...
EVENING UPDATE.
&&
.DISCUSSION...
Previous forecast mostly on track but there have been some
adjustments to POPs and fog overnight. Currently, just a few
spotty showers and storms remain. This activity should dissipate
by midnight. Areas that received rainfall today will likely see
patchy fog overnight. Therefore, have added fog into the forecast
across areas that that show radar estimated rainfall, which was
mainly across the central and northern Cumberland Plateau and
along the foothills of the east TN mountains up through northeast
TN/southwest VA.
Latest CAM guidance has slowed the arrival of showers and storms
for late tonight into tomorrow morning. Have cut POPs back due to
the slower onset time. Latest HRRR shows showers and storms not
approaching the northern Cumberland Plateau until 11Z. Will send
out new zones for POP and fog adjustments.
SR
&&
.AVIATION...
00Z TAF DISCUSSION.
Mostly VFR conditions are expected through the period. However,
additional and more widespread showers and storms will move
across the forecast area from late tomorrow morning through the
end of the period. Any shower or storm that passes over a terminal
will likely result in brief MVFR conditions. Winds will remain out
of the southwest, generally less than 15 mph.
SR
&&
.PREV DISCUSSION...
/ISSUED 733 PM EDT Sun Jul 17 2022/
SHORT TERM (Tonight through Monday night)...
Key Messages:
1. A few strong storms possible this afternoon/evening.
2. Rain chances increase Monday morning, peaking Monday afternoon
and decreasing Monday night.
Discussion:
Showers and storms that have developed so far have remained anchored
to the terrain. The CAMS generally show this pattern continuing for
the rest of the afternoon, with the HRRR pushing some activity into
the northern Valley around 00Z. By midnight, most of this activity
will likely have dissipated. However, the showers over western KY
associated with a shortwave trough will be approaching later in
the night. There is good agreement among the models that it will
be entering our northern Plateau counties around the 10-12Z time
frame, so the forecast will raise PoPs to likely there by 12Z.
Instability will be elevated and quite limited at this time, so
strong to severe storms are not expected. Convection should
blossom in the midday hours as the upper trough gets closer and
instability becomes surface-based. The tall, skinny CAPE profiles,
high LCL to freezing level thickness, and PW values near 2 inches
suggest a potential for locally heavy rainfall, but not much of a
severe threat given low DCAPE values. Precip chances will
decrease late in the day behind this initial wave, but the main
trough axis remains to our west for the first half of Monday
night. Will keep PoPs going through midnight, highest in the
eastern half, with a west to east decrease after 06Z as the trough
passes overhead with dry air aloft building in behind it.
DGS
LONG TERM (Tuesday through Sunday)...
Key Messages:
1. Daily chances for showers and storms will continue throughout the
week with elevated chances later on Wednesday and into Thursday.
2. Temperatures will be generally near normal with increasing
confidence in notably hot temperatures by next weekend.
Tuesday through Thursday
At the start of the period, shortwave troughing will be in place
with fairly broad southerly flow at the surface. A closed low will
also be noted over North Dakota with surface frontogenesis having
taken place to its south. There are discrepancies as to how much
moisture will remain in the area with any solution suggesting higher
values to be focused in southern portions of the area. By Wednesday,
ridging will expand eastward, likely leading to decreased coverage
of diurnal convection and an increase in temperatures. The
aforementioned closed low will be moving into Ontario with its
associated frontal boundary approaching the area from the northwest.
This will be coincident with increasing moisture/southerly flow, in
addition to low-level convergence. While some minor timing
differences still exist, it is likely that the front will move into
the area by Thursday morning, outlining late Wednesday into Thursday
as a time of scattered to numerous convection. There are indications
of notable MLCAPE values of 2,500 to 3,000+ J/kg ahead of the
convection and with decently veered winds for this time of year. As
such, strong to severe storms may be of concern if these trends
continue. However, with the continued active weather in the nearer
term, no additional messaging will be utilized.
Friday through Sunday
On Friday, previous shortwave troughing will gradually lift
northward as ridging expands from the Southern Plains into the
weekend. During this timeframe, the ensemble and deterministic
consensus is for 500mb heights to reach or exceed 5,940 meters,
which indicates potential for notably hot temperatures. Based on
some indications, temperatures could be sufficient for heat advisory
criteria to possibly be met. Also, with lessened overall moisture in
place, any diurnal convection looks to be more limited in coverage
than early in the period.
BW
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 73 86 71 90 73 / 20 70 50 50 20
Knoxville McGhee Tyson Airport, TN 72 84 70 88 72 / 20 70 40 50 20
Oak Ridge, TN 72 82 69 88 71 / 20 70 40 40 20
Tri Cities Airport, TN 68 83 68 85 68 / 30 70 40 50 20
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
Area Forecast Discussion
National Weather Service New York NY
1100 PM EDT Sun Jul 17 2022
.SYNOPSIS...
An approaching warm front will lift to the north on Monday.
A cold front will then approach by Monday afternoon and move
through Monday night, followed by weak high pressure from
Tuesday into Wednesday. Another warm front will lift through
Wednesday night, followed by a weak cold front Thursday and
Thursday night. High pressure will return Friday and Saturday.
A frontal system may affect the region Saturday night into
Sunday.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Warm front lifts through and to the north overnight as the mid
and upper flow regime becomes southwesterly ahead of a shortwave
trough over the Great Lakes and OH Valley. A plume of moisture
laden air will advect into the area, with sfc dewpoints climbing
into the lower 70s in spots by morning, making it feel muggy
relative to recent days, with lows ranging from the upper 60s
inland, to the mid 70s in urban locations. Cloud cover will
increase as the front approaches.
Recent model guidance is depicting increasing shower activity,
and possibly some embedded thunder, moving through as the warm
front approaches overnight into early morning from about 3 AM
to 7 AM. Model soundings show some elevated CAPE, so a few
thunderstorms are also possible.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
As the warm front heads north on Monday, the local area becomes
warm sectored as a cold front approaches from the west. Aloft,
the mid level shortwave begins to work east through the
afternoon and passes north of the area, as surface low heads
into upstate NY and into New England into the afternoon.
Air mass in place ahead of the cold front will be conducive for
both locally heavy rainfall and strong, to potentially severe,
thunderstorms. The threat for any severe thunderstorms will be
mainly north and west of NYC where the upper forcing is
maximized as the shortwave and cold front move through. Airmass
should destabilize somewhat through the morning as cloud cover
associated with any remnant overnight convection clears out.
There is some uncertainty to how quickly this clearing happens,
with both HRRR and NBM, for example, keeping low clouds across
eastern portions of the CWA through late morning. Model
soundings are indicating 1000-2000 J/kg of MUCAPE by Monday
afternoon especially for the interior. In addition, shear should
be sufficient (30-50 kt) for organized storms, with best chance
of these again north and west of NYC. A few of the HREF CAMs
(ARW and FV3) do depict some pre-frontal trough activity across
the western zones as early as 17Z-18Z, with the main activity
pushing through by 23-03Z. Given all this, SPC has placed the
area in a "marginal" risk for severe thunderstorms, with strong
and damaging winds the greatest severe hazard from the strongest
storms. Any activity should weaken as it moves east and be
completely offshore by 04Z-06Z Tuesday.
Localized flash flooding is also possible with any stronger storms.
Generally, the lowest 1-hr FFG is in northern NJ with values between
1.5 and 2", given the recent dry conditions. Model soundings however
indicate 1.72-2.25" of PWAT across much of the area, which is near
the maximum climatological values for this time of year per SPC
sounding climo for OKX. The 12Z HREF does show some low
probabilities of more than 1 inch per hr across the Hudson
Valley, northern NJ and into the urban corridor. WPC continues
the marginal risk of excessive rainfall for the entire forecast
area, though the greatest risk of any flash flooding will be
across the urban corridor and Lower Hudson Valley with any
stronger and slower moving storms.
Temperatures will be near seasonable, with highs in the lower
and mid 80s across the board, though will feel a bit warmer
with max heat indices in the upper 80s to lower 90s across the
urban areas.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
The long term forecast will be characterized by a heat wave from
Tuesday through Friday, possibly extending into Saturday for a
portion of the region. With humidity levels also elevated,
especially Thursday, there will be the potential for heat
advisories across much of the area Wednesday and Thursday. Highs
will be in the 90s with overnight lows remaining rather high,
in the 70s, to around 80 in metropolitan area. However, no
record high max or min temps are expected to be tied or broken.
Temperature departures will be around 5 to as much as 10
degrees above normal. Maximum heat indices will be more
dependent on how high dew points will get, and how much mixing
there will be during the peak heating of the day. Mainly used a
combination of the NBM and 50th percentile NBM for
temperatures, and a combination of NBM and CONSALL for dew
points.
With the passage of a warm front Wednesday night there will be a
chance for showers and thunderstorms, especially across the interior
with the best frontal lift. A shortwave, pre frontal trough, and a
cold front will provide better upper support Thursday as the air
mass will become more unstable through the day.
Weak ridging builds Friday into Saturday with a warm and humid
airmass returning, and temperatures remaining above seasonal normals.
Another frontal system potentially impacts the area later Saturday
night into Sunday.
&&
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
An approaching warm front approaching this evening will lift to
the north on Monday. A cold front will then approach by Monday
afternoon and move through Monday night.
Except for KGON where it appears IFR or LIFR cigs may develop
just after midnight, and KISP where MVFR or IFR cigs may also
develop late, mainly VFR conditions are forecast for tonight.
However, there will be a chance of MVFR or lower cond with any
showers/tstms late tonight into early Mon morning (about 08Z-
13Z for the NYC metros, slightly earlier to the NWS and slightly
later across CT/Long Island). After a lull in activity late
morning into the afternoon, more showers/tstms could develop and
move in from the west after 20Z. Gusty/erratic winds possible
with stronger thunderstorms.
Diminishing SE-S flow tonight should become S-SW daytime Mon and
eventually increase to 10-15G20kt in the afternoon.
...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty...
AMD possible to adjust timing/coverage of any showers/tstms
late tonight into Mon morning.
.OUTLOOK FOR 00Z MONDAY THROUGH FRIDAY...
.Monday night...MVFR/local IFR cond at times with any
showers/tstms. Gusty/erratic winds also possible with stronger
tstms.
.Tuesday and Wednesday...Mainly VFR.
.Thursday...MVFR cond possible with a chance of showers and
thunderstorms, mainly afternoon into early evening. SW winds
10-15G20-25kt. Winds subside at night.
.Friday...VFR.
Detailed information, including hourly TAF wind component
forecasts, can be found at: https:/www.weather.gov/zny/n90
&&
.MARINE...
No changes to the winds and seas at this time.
SCA cond likely to develop early Mon afternoon on the ocean and
harbor, and continue into Tue morning as SW winds gust up to
25-30 kt and ocean seas build to 5-6 ft. Gusts could also
approach 25 kt at times on the Sound and bays.
SCA cond should still be ongoing on all the ocean waters Tue
morning, and into early afternoon out east.
Increasing S flow ahead of a cold front should allow ocean seas
to return to 5+ ft late Wed night into Thu. There could be gusts
up to 25 kt as well Thu into Thu evening. Winds and seas then
subside Thu night into Fri after the frontal passage.
&&
.HYDROLOGY...
Thunderstorm activity with associated heavy rainfall could lead
to minor flooding in urban and poor drainage areas as well as
localized flash flooding. With some potential for hydrologic
impacts from heavy rain WPC has placed our area in a marginal
risk of excessive rainfall.
No significant hydrologic impacts are expected Tuesday through
Sunday.
&&
.TIDES/COASTAL FLOODING...
A southerly flow increases Monday afternoon with a building S-SE
swell through the day. There is a moderate risk for the
development of rip currents at the ocean beaches in the morning,
increasing to high in the afternoon.
This high risk should continue into Tuesday as a 5-6 ft S-SW
swell with 6-8 second periods remains through the day.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...High Rip Current Risk from Monday afternoon through Tuesday
evening for NYZ075-080-081-178-179.
NJ...None.
MARINE...Small Craft Advisory from 2 PM Monday to 8 AM EDT Tuesday for
ANZ338-350-353-355.
&&
$$
SYNOPSIS...DBR/MET
NEAR TERM...DBR/MET
SHORT TERM...DBR
LONG TERM...MET
AVIATION...BG
MARINE...DBR/MET
HYDROLOGY...DBR/MET
TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Paducah KY
626 PM CDT Sun Jul 17 2022
.UPDATE...
Issued at 625 PM CDT Sun Jul 17 2022
Updated the aviation section for the 00Z TAF issuance.
&&
.SHORT TERM...(Tonight through Tuesday night)
Issued at 321 PM CDT Sun Jul 17 2022
An upper level trof, currently extending from over the Great
Lakes region to Missouri, will continue to push slowly southeast
tonight. Concurrently, at the surface, a weak boundary to our
northwest will also be slowly moving through the PAH forecast area
tonight into Monday. The latest HRRR shows convection becoming
widespread across the entire PAH forecast area between 01z-04z,
then gradually moving southeast through the overnight hours. Went
with likely to categorical PoPs through this evening, then chances
will slowly decrease from northwest to southeast late tonight
through Monday. Our northwest and west counties should be dry by
Monday afternoon, with just a few light showers possibly lingering
in our far southeast counties early Monday evening. Additional
rainfall amounts are expected to be generally in the one to one
and a half inch range, with isolated higher amounts.
Portions of southeast Missouri, far west Kentucky and extreme
southeast Illinois remain in a Slight Risk for severe storms,
where we have had the best heating and least rainfall. If storms
can get going in the next few hours, we could see a few strong to
severe storms into this evening. This will be something to watch.
The clouds and precipitation have given us a break from the above
normal temperatures today, and this will also be the case
tomorrow. With lows tonight and Monday night around 70 degrees,
highs Monday will range from the middle 80s east to near 90
degrees west. The heat begins its return Tuesday, when we expect
highs to range from around 90 degrees northeast to the middle 90s
southwest. With dew points in the lower 70s, afternoon heat
indices in southeast Missouri will reach from 100 to around 105
degrees. Lows Tuesday night will be much warmer in the middle to
upper 70s.
.LONG TERM...(Wednesday through Sunday)
Issued at 321 PM CDT Sun Jul 17 2022
The long term forecast period will feature mainly hot and dry
weather through the weekend with an upper ridge building into the
Middle Mississippi Valley area.
With breezy southwesterly winds bringing in ample moisture,
Wednesday looks to be the most concerning day of the week for heat
related issues. Highs are forecast to be in the mid-90s for the
Evansville Tri-State to near or just above 100 in Southeast Missouri
with peak heat index values of 105-110 likely for most of the area.
A shortwave low moves across Lake Superior into Ontario Wednesday,
resulting in a weak cold frontal passage through the Quad State
Wednesday evening. While there is plenty of CAPE and DCAPE along
with high mid-level lapse rates, a strong capping inversion sharply
limits PoPs in the ensembles ahead of the front. The lone PoPs left
in the NBM are Wednesday evening for the KY Pennyrile area, as
precip chances are higher southeast of the forecast area. The front
will provide some temporary relief from heat and humidity, though
highs on Thursday are still projected to be in the upper-80s to mid-
90s.
The upper ridge expands eastward into the Middle Mississippi Valley
for next weekend. Some models are forecasting extreme heat,
particularly the operational GFS, though this appears to be way
overdone. Due to the clear overstating of highs in some models, and
the slight chance of showers/storms for the weekend in some ensemble
members that tend to occur in scenarios with a reduced intrusion of
the ridge, highs were nudged lower relative to the NBM
initialization, but still at or slightly above the 50th percentile.
This puts highs Friday-Saturday in the mid to upper 90s with
temperatures around 100 possible in Southeast Missouri.
&&
.AVIATION...
Issued at 625 PM CDT Sun Jul 17 2022
Showers and thunderstorms are moving through the Quad State region
this evening. Clusters of storms in a very disorganized line will
provide for a few hours in which thunder is most likely at each
terminal. Thunder cannot be ruled out completely overnight or
with potential new convection in the morning in Western Kentucky
but is left out of the TAF due to low probability. Vsby will drop
with thunderstorms and heavy rain, and will likely remain somewhat
reduced overnight as fog forms. IFR cigs move in behind the main
storm line, especially for KEVV/KOWB, while other sites may only
drop to MVFR. Aside from thunderstorm gusts, winds will be light,
shifting from southwesterly to northwesterly.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...ATL
SHORT TERM...RST
LONG TERM...ATL
AVIATION...ATL
Area Forecast Discussion
National Weather Service Shreveport LA
725 PM CDT Sun Jul 17 2022
...New UPDATE...
.UPDATE...
Issued at 725 PM CDT Sun Jul 17 2022
The latest RAP mid-level analysis indicates a high pressure ridge
centered over Colorado and extending across much of the
Intermountain West and Desert Southwest. Meanwhile, a trough is
located over the Great Lakes and Ohio Valley. Between these two
features, the local area is in a northwesterly flow. At the
surface, a 1016mb high is centered over the western Gulf of Mexico
with a broad pressure gradient across the region. A weak 1008mb
surface low is located in northeastern Oklahoma. A frontal
boundary extends from central Oklahoma eastward to the low and
across northern Arkansas. Ahead of the boundary, the local area is
hot and humid with temps still in the mid to upper 90s this
evening and dew points ranging from the mid 60s in East Texas to
the lower 70s in the ArkLaMiss. The latest radar indicates
isolated thunderstorms along and ahead of the front boundary in
central and northern Arkansas.
Overnight, the frontal boundary will slowly slide south and then
begin to stall out across southeastern Oklahoma and central
Arkansas. Related to this feature, hi-res models are favoring
showers and thunderstorms pushing southward into the I-30 corridor
tonight. Across the far north (McCurtain/Sevier/Howard) we cannot
completely rule out a strong to severe gust with storms as they drop
south and the Storm Prediction Center has highlighted this area with
a Marginal Risk for tonight. Showers and storms will diminish with
lingering partly cloud skies over southeastern Oklahoma and
southwestern Arkansas tonight. Further southward a mostly clear
night can be expected.
Another warm and muggy night is ahead. Low temperatures tonight will
range from the mid to upper 70s in portions of southwestern
Arkansas, southeastern Oklahoma, and the ArkLaMiss to near 80 in
East Texas and northwestern Louisiana. With warm overnight lows
tonight and heat indices expected to warm into the 105-110F range
on Monday, a Heat Advisory is in effect over the next 24 hours.
/04-Woodrum/
&&
.SHORT TERM...
(This evening through Monday Night)
Issued at 251 PM CDT Sun Jul 17 2022
A weak frontal boundary will drift south across the I-30 corridor
allowing for a chance for scattered convection overnight across
southeast Oklahoma and southwest Arkansas. Front should linger
across these areas through Monday before lifting back north on
Monday night. Could see a few afternoon showers and thunderstorms
on Monday afternoon across portions of north Louisiana as an
upper-level trough slides south along the eastern periphery of a
previously established upper-level ridge across the region.
Upper-ridge to maintain sufficient subsidence to drive afternoon
high temperatures to around 100 to 105 degrees across southeast
Oklahoma and east and northeast Texas on Monday with slightly
lesser values to the east in the vicinity of the upper-trough.
However, the combination of temperatures and relative humidity
values will produce heat index values around 105 to 110 degrees
across the entire region on Monday. Therefore the Heat Advisory
will be expanded areawide for Monday.
Otherwise, overnight low temperatures will average in the upper
70s both tonight and Monday night. /05/
&&
.LONG TERM...
(Tuesday through next Saturday)
Issued at 251 PM CDT Sun Jul 17 2022
Dangerous heat will continue for the Ark-La-Tex through the rest of
the week into the weekend as ridging gradually rebuilds from the
west. This is a result of upper-level troughing that undercuts the
ridge as it heads west across central Mexico, displacing the ridge
axis back into Texas. Maximum temperatures in the upper 90s and
lower 100s combined with dew points in the low 70s each day will
likely prompt additional Heat Advisories, while minimum temperatures
in the upper 70s (potentially reaching the 80-degree mark in some
areas) will reduce the time and quality of any nighttime recovery
period, especially for outdoors activity.
Prolonged dry conditions will boost drought development, especially
with category D1 drought (moderate drought conditions) having spread
through all of Northeast Texas into Oklahoma and across the
Texas/Louisiana border. Isolated areas in Northeast Texas have
already reached category D3 drought (extreme drought conditions)
with further drought development likely in that area as the best
chances of precipitation for the long term period remains in eastern
Louisiana parishes. A majority of that rain is more certain to fall
on Thursday afternoon with more uncertainty on any additional
foreseeable rainfall as the ridge continues to build eastward over
the Four State Region into early next week. /16/
&&
.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Sun Jul 17 2022
VFR conditions will mostly prevail across the terminals through the
TAF period. As a frontal boundary approaches from the north, a brief
shower or thunderstorm cannot completely ruled out at Texarkana
and El Dorado in the 06z-015z window, however probabilities are
so low that it is just mentioned as VCSH for now. Winds will be
south-southwesterly at 5-10 kts overnight, increasing by mid-
morning on Monday to 10-15kts with gusts to 20kts. /04-Woodrum/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 81 101 80 101 / 10 20 0 0
MLU 79 97 76 99 / 20 20 10 0
DEQ 77 103 77 105 / 30 10 0 0
TXK 81 104 81 105 / 20 20 0 0
ELD 78 97 76 98 / 20 20 10 0
TYR 81 104 79 104 / 10 20 0 0
GGG 80 103 79 103 / 10 20 0 0
LFK 78 100 77 101 / 0 10 0 0
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Heat Advisory until 7 PM CDT Monday for ARZ050-051-059>061-
070>073.
LA...Heat Advisory until 7 PM CDT Monday for LAZ001>006-010>014-
017>022.
OK...Heat Advisory until 7 PM CDT Monday for OKZ077.
TX...Heat Advisory until 7 PM CDT Monday for TXZ096-097-108>112-
124>126-136>138-149>153-165>167.
&&
$$
SHORT TERM...05
LONG TERM....16
AVIATION...04
Area Forecast Discussion
National Weather Service Las Vegas NV
1158 AM PDT Sun Jul 17 2022
.SYNOPSIS...Another couple days of monsoonal thunderstorms
expected, favoring the higher terrain. Monsoon moisture retreats
by mid-week reducing rain/thunder chances to below mentionable
levels through the remainder of the week. Temperatures will
remain above-average until next weekend when monsoonal moisture
begins to filter back into the area.
&&
.SHORT TERM...Today and Tomorrow.
This morning`s MCV is quite evident spinning over northwestern
Clark County as of 1130AM this morning. This vort max from last
night`s convection led to moderate and briefly heavy rainfall
across the county this morning and brought rare rainfall to Death
Valley as well.
Moving into into the afternoon, this MCV will continue to push
northward and wrap around the periphery of the H5 ridge in place.
12Z HRRR takes this and dissipates it moving into north-central NV
as it gets enveloped by the synoptic flow to the north. As it
takes this track, further convection is expected to be enhanced
across Nye and Lincoln counties this afternoon, some of which is
already taking place.
Farther west, another round of Sierra convection is beginning due
to southerly low and mid level flow riding up the Sierra slopes to
the west. While this area isn`t as robust from a moisture
standpoint, there is enough instability and minor shearing to
allow some updrafts to grow enough to produce some marginally
severe winds and briefly heavy rainfall. Owens Valley may receive
some 50+ mph thunderstorm outflows or rock/mudslides if these
storms are able to tap into these ingredients this afternoon.
The 12Z HREF again shows a similar pattern to today for tomorrow,
with morning convection in the southern CWA due to another MCS in
Sonora riding up the ridge into the Great Basin. Tomorrow`s lacks
a decent inverted trough however so unclear whether this
convection will organize into a MCV or simply push outflow our
direction. HREF members maintain updrafts at least into the lower
CRV for tomorrow morning though so either way, the environment
will continue to be favorable for morning convection again
tomorrow morning which will largely steer the evolution of
convection for the rest of the day.
.LONG TERM...Tuesday through Next Week.
Not much change in the long term expectations. Still expecting
PWAT values to decrease across much of the area and even fall to
below normal for a brief period late week per latest ensemble
meteograms. With the high pressure still in place, heating will
stay above average with subtle vort energy wrapping around the
high. This will set the stage for at least a few days of dry
conditions and confine PoPs to Arizona for the most part. Even
Mohave may have a dry afternoon or two Thursday or Friday, and
rely on convection to the east to kick off outflows for any
precip.
Heading into next weekend, moisture begins to build back into the
Great Basin. A tropical system coming off the coast of Mexico
pushes northwest but out into the Pacific in response to our
entrenched H5 ridge playing blocker. So instead of deep tropical
moisture advecting into the region, the typical northern Mexico
set up should return by next weekend. However, with the ridge
potentially shifted west, much of the upper level features that
lead to more widespread PoP potential may be lacking and high
terrain continues to see the most convection, at least initially.
&&
.AVIATION...For Harry Reid...Light and variable winds should
continue for another hour or two. Once the cloud debris from earlier
storms clears out and stronger heating ensues, winds should favor an
easterly direction, potentially southeasterly. This evening, winds
are expected to turn to the south-southwest persist through the
night. Best chances for thunderstorms outflow will be in the late
afternoon. There could also be a round of thunderstorms tomorrow
morning, similar to what we saw this morning. At the moment,
confidence in this is not overly high, but will be something to
monitor. Erratic and gusty winds will be possible with any storms
that form in the valley. FEW-SCT cumulus this afternoon, with bases
around 12 KFT. SCT-BKN clouds at 12 KFT tomorrow morning as moisture
and potentially precipitation pushes north.
For the rest of southern Nevada, northwest Arizona and southeast
California...Isolated afternoon thunderstorms likely to develop in
northwest Arizona, southern Nevada, eastern San Bernardino County,
and the Sierra crest. Gusty and erratic outflow winds of 30+ mph
will be possible with any nearby storms. Otherwise, generally south
winds are expected to prevail across the area, with KDAG being the
exception. KDAG should see light northeast winds this afternoon
before their typical southwest push this evening. Scattered mid-
level clouds at 10-12 KFT this afternoon. Sites in the Colorado
River Valley could once again see some overnight/early morning
storms, similar to what happened last night.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...TB3
AVIATION...Woods
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