Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/09/23
Area Forecast Discussion
National Weather Service La Crosse WI
1039 PM CDT Sat Jul 8 2023
.DISCUSSION...(This evening through Saturday)
Issued at 145 PM CDT Sat Jul 8 2023
Key Messages:
- Isolated showers/storms possible north of I-94 through early
this evening.
- Additional shower/storm chances into next week, highest (40-60%
chance) late Monday and again Wednesday. Low chances for a
strong/severe storm Monday afternoon/evening.
- Highs expected to rise to near 90 in spots on Monday, but
otherwise near to below average temps over the next week.
This Weekend...
A seasonably cool, low humidity airmass prevails over the Upper-
MS Valley this weekend within northwest flow aloft. Through early
afternoon, GOES visible imagery has shown growing cumulus
developing across northern Wisconsin with a few lightning strikes
detected. Isolated showers or a storm remain possible into the
evening hours north of I-94 as a weak upper level trough skirts
through the larger trough. RAP soundings show weak, skinny CAPE at
Medford (only 200-500 J/kg of MLCAPE), given the seasonably dry
airmass. Accordingly, a few lightning strikes would be the primary
hazard with any isolated storms. Otherwise, patchy fog could form
in low-lying areas again early Sunday with light boundary layer
flow. Temps will rebound closer to seasonal averages on Sunday as
low-level warm advection commences ahead of the next front. A
small (20%) chance for shower exists in northern WI by evening as
synoptic forcing associated with a strong shortwave trough across
southern Canada brushes the area. However, with minimal
instability forecast, chances for any consequential precip are
quite low.
Monday-Tuesday:
A potentially more active pattern is shaping up through the work
week as a series of shortwave troughs pass from the plains across
the Mississippi Valley within quasi-zonal flow south of a deep
trough centered up toward Hudson Bay. Right now, the time windows
for higher rain chances (50-60%) look to be later Monday
afternoon/night as a front sags south and again around Wednesday as
another progressive shortwave trough moves through.
Global ensembles (EPS/GEFS/CMC) have consistently indicated Monday
will be the warmest day of the week with breezy southwest surface
flow and 925 mb temps into the 23-24C range. Highs around 90F are
likely in spots. Storm chances will increase later in the
afternoon/evening as the front begins to move south across the
area. It remains to be seen how much moisture transport/pooling
ahead of the front will offset boundary layer mixing, but models
generally indicate a pool of moderate instability ahead of the
front in the afternoon. The stronger deep layer shear should lag
the front, which could limit more organized strong, severe storm
potential, especially southward into the evening/night, but at
least a lower end risk of severe storms exists with SPC indicating
a marginal (level 1 of 5) risk on Monday and the GEFS-based CSU
machine learning probabilities also showing a low end (5-15%)
risk of severe storms across MN into northern/western WI. Storm
potential on Tuesday will likely hinge on frontal position, but
trends have been for the front to sink south of the area through
the morning, limiting additional storm potential.
Wednesday-Saturday:
Although confidence in the general pattern evolution is fairly well
agreed upon by global ensembles, smaller scale differences will
likely impact details, especially with convection.
A belt of mid-level westerlies with embedded perturbations will pass
across the Midwest during this time south of a strong trough across
Canada. As mentioned above, right now, confidence is highest for one
such wave to pass across the area on Wednesday, with lower
confidence in timing of chances deeper into the week. Although the
stronger mid-level flow will be more favorable for organized
storms across the Mid to Upper Mississippi Valley, predictability
of convective placement, evolution, and severity is fairly low at
this range, and will depend on factors such as the placement of
the low-level baroclinic zone/instability axis, timing/placement
of shortwave troughs, and evolution of upstream convection.
Loosely speaking, though, both the GEFS/EPS ensembles favor the
stronger instability/deeper moisture to hold a bit south of the
area for mid to late week where the CSU severe weather machine
learning algorithm also indicates broad-brushed low-end severe
weather probabilities. Confidence is higher for temps to be near
or below average with the influence of the longwave trough
extending into the Upper MS Valley.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 1039 PM CDT Sat Jul 8 2023
Main taf concern is the potential for fog development in river
valleys tonight. Surface ridge is expected to build into southern
Minnesota/central Iowa tonight. Light winds...clear skies will
develop an inversion across the area after 06z Sunday. Patchy fog
is expected to develop in river valleys. Question will be if fog
will be widespread enough in Mississippi River Valley to impact
LSE taf site. Continued with patchy fog...BCFG...after 08z Sunday
at the LSE taf site and will continue to monitor on how
widespread fog is in the Mississippi River valley. After fog
erodes from LSE taf site Sunday morning...VFR conditions can be
expected to prevail at both taf sites.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...JM
AVIATION...DTJ
Area Forecast Discussion
National Weather Service Binghamton NY
937 PM EDT Sat Jul 8 2023
.SYNOPSIS...
Tomorrow, an upper-level disturbance passing
through the region will bring rounds of widespread rain showers
with localized flash flooding possible, especially across
eastern NY and NE PA. High pressure then builds into the area
early next week then gives way to a cold frontal boundary late
in the week.
&&
.NEAR TERM /THROUGH SUNDAY NIGHT/...
As of late evening, only one stray thunderstorm remains in
Sullivan county and will continue the slight chance of another
one for a few more hours.
Looking more into tomorrow with this update. Trends are a
little slower developing the showers and thunderstorms across
the region. While an isolated shower or storm can not be ruled
out, the majority of our activity should not get going till 11am
or so. The ending timeframe continues to be centered in the
evening hours. Both the HRRR and RAP indicate portions of our
area get to around 1,000 J/KG of mixed CAPE coupled with around
30 knots of 0-6KM bulk shear. This keeps a potential for gusty
winds from thunderstorms in the forecast. Also while the speed
of the thunderstorms looks decent, a look at modeled soundings
shows some Parallel vectors indicative that training of showers
and thunderstorms is still a possibility. So, the heavy
rainfall/flooding threat and flood watch are still expected/ in
effect. Our one saving grace would be if thunderstorms organize
very quickly to our south cutting off some of the deeper
moisture getting into our area, this possibility will be
monitored.
Reduced any chances for pop up showers and thunderstorms east of
I-81 this evening with the early evening update. Only a few
spotty showers have developed across Pike and Sullivan counties
so far.
330 PM Update...
Satellite imagery paints a picture of puffy cumulus clouds over
our area this afternoon. With a semi-stalled front lingering
over the area, it may help to develop some showers and storms in
the Catskills and Poconos regions this afternoon. Overnight
tonight, some patchy fog may creep into some NE PA areas from
the marine layer. Otherwise, a relatively fair weather day is
expected through tonight.
An upper-level disturbance is expected to swing into the area
tomorrow, and with interactions with the aforementioned semi-
stalled front, it will help to produce widespread showers and
chances for thunderstorms tomorrow early afternoon through the
evening. With PW values approaching 1.7-1.9 inches and pockets
of up to 2.0 inches for eastern NY, as well as deep, warm cloud
layers between 10-12kft and long, skinny CAPE in modeled
soundings, this is a good set up for potential localized flash
flooding. Earlier in the day, guidance suggested a more eastern
NY localization for higher chances of potential flash flooding,
but pockets of higher PW values have drifted westward into some
of the Central NY counties, as well as the NE PA counties.
The heaviest showers are expected to be between early afternoon
and the evening timeframe. As far as amounts go, 1-2 inches of
rain is expected across the area, with heavier amounts from the
Catskills and Poconos eastward of 2-3 inches. In saturated
areas, this may be enough to cause localized flash flooding.
Ahead of the disturbance in the morning, there may be some pop-
up strong to potentially severe storms with some higher amounts
of CAPE in modeled soundings, especially in NE PA. If any
severe storms were to develop, the best timeframe would be mid-
morning through early afternoon. Once the showers begin to move
through early afternoon, it`ll squash chances for stronger
storms to generate and develop.
&&
.SHORT TERM /MONDAY THROUGH TUESDAY/...
130 PM update...
A slow moving upper short wave and weak surface front will be
lifting to the north/northeast across interior northern New
England on Monday. The back edge of this system will be brushing
parts of central NY and northeast PA with some scattered
showers and storms Monday afternoon and early evening. Some
storms may produce gusty winds and heavy downpours.
An upper level ridge axis will build in from the west Monday
night into Tuesday and allow for a brief period of quiet weather
through the day Tuesday.
Temperatures on Monday will be on the slightly cooler side with
highs only into the upper 70s to lower 80s. Overnight lows Mon
night will drop into the upper 50s and lower 60s. High
temperatures on Tuesday will rebound back into the mid to upper
80s...with only a bit of humidity as dew points nudge back into
the lower 60s.
&&
.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
130 PM update...
The upper level ridge axis will be shifting to the east into
the Canadian Maritimes Tuesday night as another broad trough
rotates through the Great Lakes. The initial push of this wave
will become washed out with time through the day Wednesday with
weak forcing interacting with a warm and humid air mass to
trigger a few afternoon/evening showers and storms.
A deeper trough over the mid MS Valley region late Wednesday is
forecast to lift to the east/northeast over the northern Ohio
Valley and eastern Great Lakes into the interior Northeast US by
Thursday. The result of this pattern will be to advect into
central NY/ne PA a more humid air mass with plenty of deep
moisture and instability that will create favorable conditions
for widespread showers and storms. The thunderstorms may be
capable of producing heavy rainfall and strong wind gusts. The
timing of the storms is still uncertain given the ill-defined
synoptic pattern that unfolds during the latter half of the work
week.
The air mass looks to remain hot and humid, although relatively
seasonal for this time of year...with periods of showers and
storms during the warmest times of the day. Highs later in the
week will remain in the upper 70s to mid 80s with overnight lows
in the 60s.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
VFR conditions expected across the region through the evening
hours. Tonight, fog could develop across AVP/BGM/ELM as
southerly flow brings more moisture into the area ahead of the
next storm system. Tempo MVFR visby was included overnight as
confidence was not high enough to drop to IFR.
Sunday will see a storm system move into the region, bringing
scattered thunderstorms and heavy rain to the region. Guidance
shows the best chance for thunderstorms is across AVP and BGM.
A Prob30 line was included to account for this, with visby
dropping down to IFR during heavy showers. Heavy rain will also
probably drop visby down to IFR but guidance is not giving
enough confidence in the timing of this so MVFR was used.
For ELM/ITH/SYR/RME, heavy rain showers and scattered
thunderstorms are expected during the late morning and early
afternoon. Confidence in thunderstorms was not high enough to
include in the TAFs but the chance is still there. Heavy rain
dropping visby down to at least MVFR is the main threat at these
terminals. Visby will probably fall to IFR during the heaviest
rain showers but confidence in timing and location of these
showers was not high enough to include it in this set of TAFs.
MVFR visby was used to capture the rain showers and is expected
to last through the TAF period.
Outlook...
Sunday night...Lingering showers and fog development could
bring restrictions.
Monday through Wednesday...Mainly VFR expected, but still a
chance for mainly afternoon and evening scattered showers and
thunderstorms.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...Flood Watch from Sunday afternoon through Sunday evening for
PAZ038>040-043-044-047-048-072.
NY...Flood Watch from Sunday afternoon through Sunday evening for
NYZ023>025-044>046-055>057-062.
&&
$$
SYNOPSIS...KL
NEAR TERM...KL/MWG
SHORT TERM...BJT
LONG TERM...BJT
AVIATION...JTC
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
946 PM CDT Sat Jul 8 2023
.UPDATE...
Issued at 946 PM CDT Sat Jul 8 2023
Convection has trended down this evening as expected with isolated
activity crossing the I-94 corridor. With this update pops were
trimmed down to linger isolated showers and thunderstorms in the
south for a couple more hours, otherwise no major changes needed.
UPDATE Issued at 653 PM CDT Sat Jul 8 2023
Convective activity is currently moving through western and
central North Dakota, though seeing some decreasing coverage in
lightning recently. Surface based instability should diminish
rather quickly this evening as surface temperatures cool, though
we may still see a few showers with very isolated lightning
continue on for a few more hours into the later evening.
&&
.SHORT TERM...(This Evening through Sunday Night)
Issued at 313 PM CDT Sat Jul 8 2023
Isolated showers and thunderstorms will continue across portions
of western and central North Dakota through the early evening.
Above average temperatures return on Sunday.
This afternoon, a surface low was located over southeastern
Saskatchewan with a warm front extending to it`s southeast into
north central North Dakota, and down into the James River Valley.
At the mid to upper levels, a couple of weak waves are currently
noted on water vapor satellite imagery over eastern Montana and
western North Dakota. These waves will continue to move across
the state through the day under northwest flow aloft. Isolated
showers with a few lightning strikes remain ongoing across two
areas; one over the west (mainly the northwest) and the other over
the Devil`s Lake Basin and into the James River Valley.
Instability will remain rather limited through the day with RAP
mesoanalysis trends suggesting the best MLCAPE values (500 to 1000
J/kg) will mainly be across the north and over the James River
Valley through peak heating. Shear will be slightly better than in
previous days with effective values in the 25 to 35 knot range.
While these parameters are not overly favorable for severe
weather, low level lapse rates are steep and forecast soundings
show dry lower levels (inverted V profile). Thus, winds could
become a bit gusty underneath any stronger storm. Low freezing
levels could also lead to some small hail. That being said, storms
will have a tough time growing too tall given weak lapse rates in
the mid levels.
Showers and storms will diminish around and after sunset with the
loss of heating and the final wave moving out. Expect overnight
lows in the 50s.
On Sunday, the western US ridge will amplify as it slowly nudges
towards the region, keeping us in northwest flow aloft. During the
afternoon there should be plenty of sunshine and a return to
slightly above normal temperatures. Highs will mainly be in the
mid to upper 80s but a few lower 90s are possible. Sunday should
mainly be dry for western and central North Dakota, but a backdoor
cold front will approach the Turtle Mountains in the evening.
While most of the precipitation should remain east of our forecast
area, we could see a shower or storm over Bottineau or Rolette
county along the front in the evening. Sunday night lows will be a
touch milder, mainly in the mid 50s to lower 60s.
.LONG TERM...(Monday through Saturday)
Issued at 313 PM CDT Sat Jul 8 2023
A few strong to severe storms will be possible late Monday across
the southwest and south central. Chances for hit and miss showers
and storms remain in the forecast nearly every day in the long
term forecast period.
The backdoor cold front mentioned in the short term will continue
to sag south across the state, stalling out somewhere across the
south central and southwest by Monday afternoon. The location of
this boundary will be very important with regards to our severe
weather potential. If it stalls out well south in South Dakota,
instability will be tough to come by. If it stalls out across
southern North Dakota, we could see 1000 to 2000 J/kg collocated
with 35 to 45 knots of deep layer shear. The main upper forcing
will likely arrive to western North Dakota late, so we may not see
storms in the forecast area until the evening or overnight hours.
Long story short, if we can get enough instability in place
across the southwest and south central, the environment would be
favorable for a few strong to severe storms.
Highs on Monday will be cooler on the north side of the backdoor
front, in the 70s over the north central and into Devil`s Lake
Basin. However, we will still see warm highs across much of the
south central and west, in the lower 80s to lower 90s.
The upper ridge will continue it`s approach as it flattens on
Tuesday, leading to zonal flow aloft. The backdoor cold front
will sag even further south on Tuesday, leading to much cooler
temperatures for the entire area. Highs will be in the upper 60s
to mid 70s. A couple of stronger waves will move through the zonal
flow Tuesday and into Wednesday, which may lead to our most
widespread precipitation period during the long term. While this
won`t be a washout, we should see widely scattered to numerous
showers and storms. Some guidance advertises some stronger
instability across far southwest North Dakota by late Tuesday with
strong shear. However, this solution appears to be an outlier at
the moment with most guidance keeping the stronger instability to
our west and south. Towards the end of the week, we transition
back into northwest flow aloft as the ridge pops back up to our
west.
Wednesday will remain unseasonably cool with highs in the upper
60s to upper 70s with only a slight warmup on Thursday with highs
in the 70s. Highs then remain in the mid 70s to lower 80s Friday
and Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 653 PM CDT Sat Jul 8 2023
Isolated showers and thunderstorms will continue to move through
portions of western and central North Dakota this early evening
before diminishing by late this evening. While overall VFR
conditions are expected, brief periods of lower visibility in
heavy rain are possible if a thunderstorm impacts any one TAF
site, though confidence in location and timing is low. Gusty
erratic winds will also be possible with any thunderstorm. Lower
level winds increase in the southeast tonight, which may cause
some LLWS at KJMS early Sunday morning. On Sunday winds become
westerly at 10 to 20 kts, gusting to 25 kts in the north and east.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...AE
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...AE
Area Forecast Discussion
National Weather Service Cheyenne WY
529 PM MDT Sat Jul 8 2023
.SHORT TERM...(This evening through Sunday night)
Issued at 200 PM MDT Sat Jul 8 2023
Severe convection ongoing this afternoon. Concerns deal primarily
with the severe convection today...followed by warmer/drier
weather Sunday into next week.
Currently...Convection developing along a line from
Scottsbluff...northwest to Lusk this afternoon. Thinking maybe
this is along an old outflow boundary line from this mornings
convection. This area is also where skies cleared out early and
SBCAPES are up near 2000J/KG.
As the afternoon draws on...expecting low clouds to clear across
southeast Wyoming with instability increasing to 2000 to 2500J/KG.
0-6km shear is definitely there with 40-45kts and mid level lapse
rates 7-9C/KM. Looking like latest HRRR simulated radar is
handling these storms pretty good. Storms moving from northwest to
southeast and stay discrete across southeast Wyoming. So all
modes of severe weather can be expected. Current 0-3km helicity
across the southern Panhandle currently around 250 m2/s2...so this
area would be the best area for tornado development. HRRR
simulated radar shows storms continuing through 03Z this evening
before decreasing in coverage and intensity.
Much warmer and drier Sunday as upper high moves over the CWA.
ECMWF/NAM showing a few storms down here across Laramie County
and the south Laramie Range. Looking at afternoon highs climbing
into the upper 70s and low 80s area wide.
.LONG TERM...(Monday through next Saturday)
Issued at 403 AM MDT Sat Jul 8 2023
Heading into the work week conditions will largely dry out and heat
up as the overall synoptic pattern changes. An upper-level ridge
sitting over the Rockies on Monday will usher in drier air from the
west as well as warmer 700 mb temperatures. This ridge stays in
place for most of the week, however, it will start to flatten out
and turn into more zonal flow midweek, leading to breezy conditions
across much of the CWA. During this time, temperatures will be on
the warm side with highs in the 80s and 90s. Tuesday will likely
be the warmest day of the week with temperatures in the upper 80s to
mid 90s, which is about 5 degrees above average. Precipitation
chances Monday through Wednesday look minimal, however, an isolated
thunderstorm or two during the afternoon hours cannot be ruled out
as disturbances move through the flow aloft.
The forecast becomes trickier towards the end of the week as both
the GFS and ECMWF suggest a cold front dropping down from the north
Thursday afternoon. High temperatures on Thursday will likely be
cooler than the first half of the week, however, temperatures will
depend on timing and strength of the front; details which are still
uncertain at this time. Storms will be possible with this front
since lift and jet energy will be present, but the better moisture
looks to remain north of the CWA. Friday will see the return of
cooler temperatures behind the front. Temperatures will likely be
below average with high in the 70s to low 80s. Flow aloft also makes
the shift back to northwesterlies, leading to more favorable
conditions for storms.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 521 PM MDT Sat Jul 8 2023
Wyoming TAFS...A passing weather disturbance and a moist
atmosphere will help produce a chance of thunderstorms at Cheyenne
through 02Z with gusts to 35 knots, visibilities near 4 miles and
ceilings near 4000 feet AGL, along with thunderstorms in the
vicinity at Rawlins and Laramie. Ceilings will lower to 1500 feet
AGL with areas of fog and visibilities near 2 miles at Cheyenne
from 08Z to 15Z. Otherwise, ceilings will be broken at 3500 feet
AGL in Cheyenne until 08Z. Clear skies will prevail at all
terminals after 15Z Sunday.
Nebraska TAFS...A moist atmosphere and a passing weather
disturbance will produce a chance of thunderstorms at Scottsbluff
and Sidney until 02Z with wind gusts to 35 knots, visibility to 3
miles and ceilings from 2500 to 3500 feet AGL. Thunderstorms will
be in the vicinity of Alliance until 03Z. Scattered clouds around
10000 feet AGL will prevail at Chadron and Alliance after 03Z. At
Scottsbluff and Sidney, expect broken clouds at 5000 feet AGL
until 10Z, then areas of fog with visibilities from 2 to 4 miles
and ceilings from 1500 to 2500 feet AGL until 14Z, then scattered
clouds at 5000 feet AGL.
&&
.FIRE WEATHER...
Issued at 200 PM MDT Sat Jul 8 2023
Active afternoon with showers and storms ongoing east of the
Laramie Range. Look for storms to continue through mid evening
before decreasing in coverage and intensity. Much drier Sunday
into Monday as a high pressure center currently located over
eastern Utah and western Colorado moves into the area. Very dry
for Carbon and Albany Counties Sunday through Tuesday next week
with increasing fire weather threats. Breezy to windy conditions
Monday through Wednesday across Carbon and Albany Counties with
gusts 30-40 mph and afternoon humidity well below 15 percent.
Given fuels are not ready...this may keep fire weather concerns
at bay.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...SF
AVIATION...RUBIN
FIRE WEATHER...GCC
Area Forecast Discussion...UPDATED
National Weather Service Duluth MN
802 PM CDT Sat Jul 8 2023
.UPDATE...
Issued at 802 PM CDT Sat Jul 8 2023
Minor update to PoPs/Wx around 7 PM. A subtle shortwave trough at
925 mb and 850 mb will dig southeastward across North Dakota and
into northwest Minnesota overnight. A convectively-aided westerly
low-level jet is forecast to develop over North Dakota and will
nose into northwest Minnesota later tonight per the 23Z RAP. This
evolution is supported by the 18Z runs of the GFS and NAM. Current
thunderstorms over portions of North Dakota seem to be captured
by the last several runs of the HRRR, although not quite in the
right locations. Unfortunately the HRRR isn`t handling the
precipitation over southeast Manitoba at this point.
The shortwave and low-level jet should produce an increase in
coverage of showers and storms over our area overnight. Thus
increased the coverage of PoPs across northern Minnesota starting
at 03Z tonight. The lingering question is what influence the
precipitation over Manitoba may bring into play. Opted for 20% max
probabilities overnight. Will need to increase those values
should we start to see convection developing as forecast.
&&
.DISCUSSION...(This evening through Friday)
Issued at 456 PM CDT Sat Jul 8 2023
Summary: Warm Sunday ahead of a cold front that will bring chances
for a few strong to severe storms to northeastern Minnesota.
Temperatures cool a bit to start the week before warming as the
week goes on with multiple chances for rain.
High pressure was building across the region in the wake of a cold
front pushing into central Wisconsin. A few showers and
thunderstorms were observed earlier this afternoon along the North
Shore and into northwestern Wisconsin, but this activity has
diminished or pushed out of the region for the most part. Dry and
comfortable conditions are expected for most of tonight as the
high sags to the south. A trough will push out of southern
Manitoba/southern Saskatchewan during the early morning hours.
CAMs bring some shower activity across northeastern Minnesota
during this time with activity weakening as it pushes southeast.
A cold front will then follow for Sunday out of Manitoba and
Saskatchewan. Ahead of the front, southwesterly winds gusting to
20 to 25 mph will bring warmer temperatures in with highs reaching
the 80s in most areas. This will set the stage for showers and
thunderstorms ahead of the front during the afternoon and evening
hours. Dewpoints will only be in the 50s with CAPE around 500-1000
J/kg. Shear will be nearly unidirectional at around 30 knots, so a
few organized storms may be possible early before forming into
clusters or a line as they move southeast. With marginal lapse
rates in the midlevels and thin CAPE profiles, hail up to around
an inch will be possible. DCAPE will approach 1000 J/kg with
inverted-V soundings, so gusty winds to around 60 mph will be
possible as well.
This round of activity will push through by the early morning
hours with some showers lingering through the early morning hours
with the actual front. With the front bisecting the Northland on
Monday, northern areas will see cool and mainly dry conditions
with warmer temperatures and chances for showers and
thunderstorms to the south, mainly across northwest Wisconsin. A
few storms across northwest Wisconsin may be strong to severe
during the afternoon hours before the front clears the region
heading into Monday night.
Northwest to quasi-zonal flow will then persist for the remainder
of the week. Temperatures will slowly warm through the week with
highs in the upper 70s and lower 80s possible by Friday. There
will be periodic chances for showers and storms Wednesday through
Friday as waves ripple through the upper flow pattern.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 608 PM CDT Sat Jul 8 2023
VFR conditions forecast with this update. An 850 mb low-level jet
ahead of an approaching upper-level trough late this evening and
overnight will support a chance of showers and storms. Adjusted
the timing of the VCSH in the forecast with this update to start a
bit earlier. Will need to watch trends and see if rain and
visibility reductions may be needed. Sunday will be gusty with
southwesterly winds. Diurnal Cu may provide a few showers or
storms Sunday afternoon. The next best chance of storms will be
late Sunday afternoon through Sunday night as a cold front dives
southward out of the Canadian Prairies.
&&
.MARINE...
Issued at 456 PM CDT Sat Jul 8 2023
Onshore winds late this afternoon will become southwesterly
tonight ahead of a cold front. Winds will ramp up Sunday with
gusts to 20 to 25 knots possible by the afternoon hours across
parts of both the North and South Shores leading to waves of 2 to
4 feet, mainly near the open waters/nearshore waters transition
zones. Confidence is not high enough to hoist any small craft
advisories at this time with it looking to be a borderline event,
but if trends continue, one will likely be needed. The cold front
then crosses western Lake Superior on Monday turning winds to the
northwest. Some showers and storms will be possible Sunday
afternoon through Monday evening with a few strong to severe
storms Sunday afternoon and evening along the North Shore. Gusty
winds, small hail and lightning will be the primary threats.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 50 82 60 77 / 20 40 50 30
INL 52 80 51 70 / 20 60 70 20
BRD 53 85 61 80 / 20 20 20 20
HYR 47 82 60 81 / 10 20 40 50
ASX 49 85 62 78 / 10 40 50 50
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
UPDATE...Huyck
DISCUSSION...BJH
AVIATION...Huyck
MARINE...BJH
Area Forecast Discussion
National Weather Service Goodland KS
612 PM MDT Sat Jul 8 2023
.SHORT TERM...(This evening through Monday)
Issued at 218 PM MDT Sat Jul 8 2023
As of 1:30 PM MDT, storms are beginning to develop over the
northwest corner of the Tri-State area and up into Southeast
Wyoming. So far the HRRR has had the best handle of the rapidly
developing storms. These storms are expected to be scattered storms
with supercells capable of producing all hazards. Storms are
expected to impact areas generally along and west of US-83; however,
the best likelihood for severe weather is expected along and west of
the KS Highway 27 corridor from Dundy County, Nebraska to Wallace
County, Kansas. A Severe Thunderstorm Watch is now in effect until 9
PM MDT for those on either side of the Colorado border. While all
hazards are possible, the main ones of concern are up to 2" hail,
wind gusts up to 70 mph, and heavy rainfall. A couple of
tornadoes can`t be ruled out mainly over Northeast Colorado, but
confidence is low to moderate at this time.
This environment is a bit different from the last few severe days as
it is essentially a High Shear-Low CAPE day. Low level wind shear is
out of the west to northwest at 30-60 kts, increasing throughout the
evening. MLCAPE leave a bit to be desired with values ranging from
500-~1000 J/kg. There is a bit of a capping inversion along and
east of the first row of counties in Kansas and Nebraska, which
could limit severe storms moving further east over the area.
Storms are expected to exit the Tri-State area completely between
midnight and sunrise tomorrow morning though the severe threat
should taper off during the evening hours. Overnight lows are
expected to be in the mid to upper 50s tonight.
Sunday is a bit quieter with little to no chance for precipitation
for the area. The upper ridge is expected to move further over the
area while a surface high moves over Kansas. Shortwave disturbances
are expected to help develop/strengthen a lee trough later in the
day. There may be an isolated As the disturbances move over, a
few showers and storms may be triggered; however, confidence is
very low at this time. Temperatures look to warm a bit more on
Sunday with highs in the upper 70s to lower 80s. Overnight lows
will be in the upper 50s to lower 60s.
On Monday we are expected to be under the ridge, but there will be
an upper shortwave move over from the Rockies during the afternoon
hours. For much of the day, the Tri-State area is expected to be dry
with temperatures reaching the upper 80s to lower 90s. During the
evening hours, scattered showers and storms are possible. The main
area of concern for any severe weather is mainly east of the
Colorado border. The overnight low is expected to be mainly in the
60s.
.LONG TERM...(Tuesday through Saturday)
Issued at 102 PM MDT Sat Jul 8 2023
Sprawling upper ridge will move from the Southern Plains at the
beginning of the period to the Desert Southwest by the end of the
period. Warmest temperatures will be under the ridge, so will
start the period with highs in the 90s both Tuesday and
Wednesday, then cooling off towards the end of the period to the
80s. Cold frontal timing a little faster compared to previous runs
and is moving through the forecast area during the day Thursday.
Daily thunderstorm chances continue through the entire period.
However, storms will be more scattered with proximity to the ridge
Tuesday and Wednesday, then increasing in coverage for Thursday
through Saturday as the area gets under northwest flow aloft. Deep
layer shear appears that it will be sufficient for a severe risk,
at or above 30 kts, the entire period. Front will also play a
role on Thursday for convective initiation and enhanced severe
threat, and is the same day deep layer shear is forecast to be
around 50 kts. Given daily rounds of storms and increasing
moisture, especially Thursday and beyond, flooding will also be a
potential hazard.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 607 PM MDT Sat Jul 8 2023
GLD: Adverse aviation conditions associated with thunderstorms are
expected at the beginning of the TAF period (00-02Z). Periodic
MVFR-IFR ceilings are possible late this evening and overnight.
Light easterly to variable winds are expected overnight.. becoming
southerly at ~10 knots during the day on Sunday.
MCK: Periodic MVFR-IFR ceilings are possible late this evening
and overnight. Light easterly to variable winds are expected
overnight.. becoming southerly at ~10 knots during the day on
Sunday.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...KMK
LONG TERM...024
AVIATION...Vincent
Area Forecast Discussion
National Weather Service Northern Indiana
746 PM EDT Sat Jul 8 2023
.SYNOPSIS...
Issued at 736 PM EDT Sat Jul 8 2023
Isolated rain showers, mainly east of interstate 69, will taper
off this evening. Expect dry conditions Sunday and Monday, with
highs in the upper 70s and 80s. There are additional chances for
showers and thunderstorms for the middle to latter portion of the
work week. Lows tonight will be in the mid to upper 50s and low
60s.
&&
.SHORT TERM...(This Evening through Sunday)
Issued at 338 PM EDT Sat Jul 8 2023
Most of the weather of concern in the short term will be in the very
near term with a potential of scattered showers/isolated
thunderstorms through early this evening.
Area of rain showers which exited northwest Ohio earlier this
afternoon created a stable bubble which has taken some time to
recover from. An extensive diurnal stratocu field has also developed
in the wake of these showers which has resulted in limited near sfc
warming and tempered sfc based instabilities. Latest RUC analysis
suggests best surface based instability farther to the north across
southern Lower Michigan where pocket of slightly colder mid level
temps resides.
Best insolation over the next few hours appears to be shaping up
across the far east/southeast which could allow surface-based
instabilities to briefly increase into the 1000 J/kg range before
shunted southeast. Strongest mid/upper level forcing through
remainder of the afternoon should affect far northern Indiana into
southern Lower Michigan/extreme NW Ohio, slightly divorced from
better instability developing across the far southeast. With this
disjointed nature of forcing/instability and extensive low clouds
limiting instability, will continue to message toward lessening
extent of thunder coverage. Best prospects of scattered showers
and isolated thunderstorms through rest of afternoon into early
evening will be along and east of I-69 corridor where weak sfc
convergence boundary exists with slow moving cold front, and where
some deeper low level convergence materializes over next few
hours accompanying the passing mid level trough.
Otherwise, overall trend should be toward decreasing clouds from to
west to east later this evening into the overnight, with clearing
most delayed across the far east. If clearing can occur east of I-69
corridor and especially into NW Ohio tonight, some patchy shallow
fog may develop but confidence is not high enough to include in the
forecast at this time. Temps should be relatively cool tonight via
weak low level cold advection and weak sfc high building across the
western Great Lakes.
Another upstream upper level trough from the Northern Plains should
approach the Great Lakes on Sunday, but this feature will have less
in the way of low level moisture to work with low level dry air
advection tonight into Sunday. Any isolated showers with this upper
trough should develop east of the area into central Ohio. Better
insolation on Sunday should allow highs to approach 80, perhaps a
bit cooler across southeast/far east portions of the area where
diurnal cu may be maximized.
&&
.LONG TERM...(Sunday Night through Saturday)
Issued at 338 PM EDT Sat Jul 8 2023
Quiet weather should persist Sunday night into early Tuesday, with
attention then turning to next cold front dropping south across the
Great Lakes region Tuesday night into early Wednesday. Some low
level moisture pooling in advance of this front should work into far
north/northwest locations Tuesday night into early Wednesday which
could yield enough elevated instability for isolated storms. The
biggest weather story for the first part of the week will be some
building heat as mid/upper level short wave ridging builds
downstream of large south central Canadian negative upper height
anomaly, and as low/mid level flow becomes more westerly. Highs in
mid/upper 80s by Tuesday and slowly creeping up dew points may allow
peak afternoon heat indices to approach 90 degrees Tuesday afternoon.
The cold front should stall out across the region Tuesday night into
early Wednesday morning with focus for additional convection
shifting back across the Mid MS Valley where low level jet focuses
best low level moisture convergence. This pattern could yield a few
rounds of convection as several short waves spilling over western
CONUS upper ridge get ingested into progressive westerly flow across
central CONUS. While this appears to be a more active pattern,
having confidence in putting too much detail in 6-hourly PoPs
remains low, with some potential more favorable MCS track could set
up just south of the local area. Thus, have followed trend from
previous forecast in trimming blended PoPs somewhat until greater
forecast confidence can be attained. Will continue to focus on the
Wed-early Thu periods for the highest PoPs of the long term.
Longwave pattern is expected to change little late next work week
with only a slow southward migration of strong Canadian upper low
and a series of Pacific waves potentially allowing additional
frontal waves to bring additional chances of convection. Thus,
broadbrush PoPs had to be maintained through most of the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 736 PM EDT Sat Jul 8 2023
VFR conditions are expected at the TAF sites this period, with a
surface cold front shifting just east of KFWA as of this writing.
The system responsible for today`s rain will continue eastward,
with a weak trough sweeping in behind it. This wave washes out
somewhat as it drifts into Lake Michigan later tonight-and then
upper level ridging takes over and much drier air advects in. Some
of the model guidance suggests fog/br development at KFWA between
9-12z, but I suspect that the lingering high/mid level clouds and
incoming dry air will preclude this. Dry conditions expected
otherwise, with light north-northwest flow through Sunday.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD
SHORT TERM...Marsili
LONG TERM...Marsili
AVIATION...MCD
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1018 PM CDT Sat Jul 8 2023
.SHORT TERM... (Through Late Sunday Night)
Issued at 149 PM CDT Sat Jul 8 2023
Latest surface analysis is showing that the front has moved just
south of the CWA with the SPC mesoanalysis showing MLCAPES around
1000 J/kg over the far southern counties. Still expect scattered
showers and thunderstorms over southeast Missouri and southwest
Illinois through early this evening before the RAP shows this front
moving south of Missouri by 06Z ending the rain chances. Latest run
of the HREF shows a surface high moving into the area under
northwesterly flow aloft, so will keep the forecast dry.
Temperatures will stay just below normal through tomorrow with
northerly winds and 850mb temperatures in the 10-15C range.
Britt
.LONG TERM... (Monday through Next Saturday)
Issued at 149 PM CDT Sat Jul 8 2023
No significant changes in the forecast expected into next week as
there is still good agreement in the ensembles that the upper ridge
over western CONUS will flatten out which will allow the upper flow
to become quasi-zonal over the Midwest. Monday and Monday night is
still expected to be dry as high pressure moves across the area
before the first shortwave trough will rotate south into Midwest
around the south side of the Hudson Bay low by Tuesday. Will
continue with a chance of showers and thunderstorms on Tuesday and
Tuesday night as an attendant front moves south into the area. The
ensembles then show this front becoming stationary and aligned with
the upper flow across Missouri and Illinois. At the same time, the
GFS/ECMWF are showing additional weak shortwaves moving along this
front across Missouri which warrant high chance/likely PoPs for
showers and thunderstorms Wednesday into Saturday. This pattern
looks more like an early June with the potential for one or more
MCSs producing locally heavy rainfall and possible strong storms.
After a relatively cool weekend, temperatures will begin to warm
back up on Monday and Tuesday and 850mb temperatures climb back to
near 20C with the surface flow turning out of the southwest. There
is more uncertainty in the forecast Wednesday into Saturday as the
25th and 75th percentiles of the ensemble forecast are showing a
wider spread, likely because of the presence of front. Depending
on the location of the front as well as rain/cloud coverage,
highs may only be in the 80s in the northern CWA and in the 90s
over the central/southern CWA. Either way, it will likely be warm
as 850mb temperatures will stay around 20C.
Britt
&&
.AVIATION... (For the 06z TAFs through 06z Sunday Night)
Issued at 1016 PM CDT Sat Jul 8 2023
Confidence is high in dry and VFR flight conditions through the
forecast period at all local terminals. Winds will remain light
and gernally out of the north, though they may become variable at
times through early Sunday morning.
Elmore
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Lubbock TX
649 PM CDT Sat Jul 8 2023
...New AVIATION...
.SHORT TERM...
(This evening through Sunday)
Issued at 200 PM CDT Sat Jul 8 2023
Partly to mostly cloudy skies are currently seen across much of the
region. Although this cloud cover will slightly inhibit instability,
forcing and moisture parameters are more impressive. A potent 500 mb
shortwave will track into the forecast area this afternoon from the
northwest and PWATs of 1.25 to 1.75 inches are expected, with
minimum RHs only dropping to around 30-40% today. Although the HRRR
is slightly more agressive than other high-res models, the latest
forecast is strongly bias towards its current solution as the
synoptic setup is similar to previous events in which it verified
(such as yesterday). Storms would likely form near the TX/NM border
early this evening and track eastward over the far southern Texas
Panhandle and northern South/Rolling Plains through late evening. A
few storms may become severe, particularly in the Childress area,
with damaging winds being the main threat. Large hail is also
possible.
A second round of thunderstorms remains possible in the far
northeastern Texas Panhandle early Sunday morning. If the first
round of storms comes to fruition, the second round would not have
as great a severe threat due to a more stable atmosphere. In any
case, everything should end later Sunday morning. Cloud cover in
over the northwestern portion of the forecast area will keep highs
in the upper 80s during the afternoon, while mostly sunny skies and
highs in the mid-90s are expected elsewhere.
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 200 PM CDT Sat Jul 8 2023
Not much will change with the upper pattern over the next week. An
upper high will remain over the Desert Southwest and will extend
north-northwestward into British Columbia/Alberta through late
Tuesday. This will keep the FA under northwesterly upper flow and
will allow for continued afternoon/evening rain chances Monday. The
upper high will flatten Tuesday into mid week thanks to a series of
shortwave troughs on the northern edge of the upper high. This will
also result in the upper high expanding further eastward
encompassing the South Plains region. This will, overall, keep rain
chances at a minimum. As the FA will be near the eastern edge of the
upper high, isolated rain showers could be attained if a weakness
develops in the upper high and moves over the FA as surface moisture
will remain in place. This would be welcomed as a relief from 100+
highs that are expected through much of next week. Cooler temps do
look to be in store for the weekend, however, as the Hudson Bay
upper low amplifies and the upper high migrates to the West Coast.
Not only does this place the region under northwesterly upper flow,
it increases chances for a cold FROPA Saturday/Sunday. In addition
to cooling temps this would help increase chances for welcomed
rainfall.
&&
.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Sat Jul 8 2023
The main aviation concern this evening and overnight is the
potential for TSRA at the terminals, the best potential is at
KCDS, then KPVW, while it appears KLBB has the lowest chances. In
conjunction with the t-storm activity, a outflow boundary may pass
through KPVW and KLBB this evening, even if those terminals aren`t
directly affected by the storms. However, confidence in the
strength, timing and extent of this boundary is low at this time.
In the wake of the storms overnight into Sunday morning, another
outflow boundary is expected to move southeast...likely bringing a
wind shift to the northeast through all the terminals. Finally,
low stratus is expected to fill in behind this outflow across
much of the eastern Panhandles and into the western Rolling
Plains. Low ceilings may result, primarily at KCDS, but possibly
at KPVW as well.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...19
LONG TERM....51
AVIATION...33
Area Forecast Discussion
National Weather Service Marquette MI
619 PM EDT Sat Jul 8 2023
.SHORT TERM...(This afternoon and tonight)
Issued at 1201 PM EDT SAT JUL 8 2023
Morning showers with some embedded thunderstorms slowly pressed
eastward this morning as a weak cold front stalled overhead and mid-
level shortwave pressed northeast through Lake Michigan. As the
morning progressed, rain ended in the south-central and east while a
secondary surface boundary pushed into the west, supporting
increasing low cloud cover and a light shower over Lake Superior
locations near the Keweenaw. Between the two boundaries, clear skies
supported MUCAPE increasing to ~1000-1500 j/kg in the central and
west per SPC mesoanalysis and dinural driven cloud streets began
developing around 10am EDT. Daytime temps so far have mostly inched
into the upper 60s and low 70s.
As we progress into the afternoon, cyclonic mid-level flow will
press another shortwave into Upper Michigan while the morning wave
exits east. Closer to the surface, dinural instability is expected
to continue climbing, supporting shower and thunderstorm development
by mid-late afternoon in the west, central, and east. With the cold
front still overhead and lake breezes off of Lake Michigan and
Superior, suspect enhanced low level convergence may support some
quickly developing convection across the central and east. Deep
layer shear is mostly weak, but effective shear of 20-25kts or so
may support a couple more robust thunderstorms. While severe
thunderstorms are not expected, a couple small hail cores can`t be
ruled out. CAMS don`t present much of a consensus on when
showers/thunderstorms may develop, but the overall trend and `rough`
consensus is between the 2-5pm. I suspect this will end up being
earlier based on recent satellite trends in portions of the west
and central though.
This evening, expect showers/storms to wane as the front exits,
instability diminishes, and ridging builds in. Latest HRRR suggests
some weak shower activity may persist over the central and/or near
the Bay of Green Bay past midnight and there`s some support for this
in the NAMNESt and HiRes-FV3. Overall though, activity should
diminish by or soon after midnight. As temps cool overnight into the
40s in the interior and near 50 by the lakeshores, some patchy fog
may develop. Most likely places for development is expected where it
rains today across the interior portions of the UP.
.LONG TERM...(Sunday night through Saturday)
Issued at 349 PM EDT SAT JUL 8 2023
With only minor exceptions, the CONUS remains in a completely locked
up upper air pattern with anomalous troughing over the central
portions of the continent and ridging over the coasts. Active
periods of weather will be governed by shortwave energy traversing
the base of the cutoff low trough over northern Ontario that will be
mostly stationary through the long term forecast period.
Surface ridging briefly builds in during the day Sunday, leading to
a fairly pleasant day Sunday with highs in the 70s. In the late
afternoon and evening hours, the next disturbance arrives, a surface
trough attached to the parent closed surface low in northern
Ontario. Sunday evening through Monday morning, 12Z HREF guidance
shows storms mostly confined to the Keweenaw Peninsula, far west,
and north-central portions of the UP. Thunderstorms are possible
with this round of storms, but are not expected to be widespread or
severe given nocturnal stabilization. Plentiful shear exists though
with NAM soundings showing a 40-45 kt jet from 900-700 kt.
Monday, a deeper trough and associated cold front sweep through the
UP. Cloud cover and previous precipitation will keep instability low
and mostly elevated, but with bulk wind shear in the 45-60 kt range
throughout the day and veering wind profiles near the surface, the
storm setup will be worth monitoring as details become more clear in
the coming days. At this point, the most likely output is probably
the NAM Nest, which is showing a multicell complex initiating in
Wisconsin around 21Z and moving towards the southern UP around
00Z, but more hi-res guidance will be needed before any confidence
can increase in that solution. With continuous warm advection at
850mb from southwesterly flow, some areas of the southern UP could
reach almost 90 degrees should rainfall not occur prior to the
diurnal max.
Thunderstorm and rain chances linger into Tuesday morning before
clearing out west to east. A dry airmass under mostly zonal flow
will keep Tuesday mostly dry before the next upstream shortwave
arrives Wednesday morning from the southwest. Expecting a glancing
blow from a fast-moving and weak surface low, so some rain is
expected but torrential rain and/or severe weather is unlikely.
Ensemble solutions diverge significantly for the Thursday and
beyond, but the pattern remains: stubborn troughing over central
North America and ridging over the coasts with shortwaves around the
trough keeping rain chances active through the middle of the month.
Through next week, in addition to the active rain chances,
temperatures remain generally below normal for July standards.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 619 PM EDT SAT JUL 8 2023
Expect VFR at all sites. By early morning, some fog/mist may develop
and impact KSAW from rain this afternoon, but expect this to clear
as the sunrises.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 349 PM EDT SAT JUL 8 2023
Winds will largely remain at or below 20 knots throughout the
forecast period. The only exceptions to this appear to be Sunday
night, when a passing cold front will kick wind gusts up to 25
knots, first out of the south and then veering westerly by Monday
morning, when winds fall below 20 knots once again. Because of the
changing wind directions, waves should remain below 5 feet, with the
only 4 foot waves expected being Sunday night into Monday southwest
of Caribou and Michipicoten islands. Some marine fog and haze is
possible overnight tonight in the eastern portions of Lake Superior.
Additionally, there are chances for thunderstorms across Lake
Superior Sunday night through Tuesday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...GS
AVIATION...07
MARINE...GS
Area Forecast Discussion
National Weather Service Portland OR
238 PM PDT Sat Jul 8 2023
.SYNOPSIS...Moderate onshore flow will continue into early next
week, bringing marine stratus inland. Daytime temperatures will
be slightly below normal to near normal for early July. Upper
low pressure offshore, along with south to southwest flow aloft,
will bring a chance of showers/thunderstorms along the Cascades
crest this afternoon and evening along with tomorrow afternoon
through early Monday. Slightly warmer temperatures returning mid
to late next week.
&&
.SHORT TERM...Saturday through Monday...Onshore flow remains the
dominant weather pattern over the short term forecast. Stratus
did indeed spread inland this morning and blanketed the entire
lower elevations from the western Cascade foothills all the way
to the coast. Visible satellite imagery early this afternoon is
showing stratus slowly dissipating from the south to the north
both inland and along the coast. This stratus is limiting
temperatures as most locations west of the Cascades remained in
the mid to upper 60s as of 1 pm PDT. However, locations that did
not observe stratus are already in the 70s to low 80s. Will
likely observe similar conditions to yesterday where locations
that remain under stratus beyond 2 pm PDT will only warm into
the low to mid 70s. These conditions will likely occur again
tomorrow as HREF indicates similar stratus intrusion inland
likely.
Surface pattern will remain relatively consistent with high
pressure over the Pacific and lower pressure over eastern
Washington and Oregon. This is causing tighter surface pressure
gradients in the afternoon hours, which is causing breezy
onshore winds in the afternoon and evening hours, mainly through
the Columbia River Gorge and Coast Range gaps. In the upper
levels, a longwave trough remains offshore with a weak shortwave
moving through Oregon today. This wave has shifted upper level
flow more south to southwesterly, which could bring enough
instability west from eastern Oregon to produce isolated showers
and thunderstorms over the Cascade crest in the afternoon and
evenings hours today and tomorrow. Chances are slim today
(10-15%) with better chances along the eastern Cascades. A more
portent shortwave is slated to move through the PacNW tomorrow
evening into Monday morning with southwest upper level flow to
continue, as indicated by ensemble guidance. Confidence is
increasing in the potential for nocturnal showers and
thunderstorms tomorrow evening into early Monday over the
Cascades. NAM guidance is indicating 100-200 J/kg of elevated
instability, especially over the Columbia River Gorge and
Skamania County. Additionally, CAMs such as the HRRR and FV3
have indicated the potential for cells to form in these areas,
as well.
The shortwave passage will also produce another stronger onshore
flow push with breezy winds continuing through the Columbia
River Gorge and along the Cascades crest Monday. Temperatures
are also expected to be cooler with NBM indicating lower
elevations only topping out in the mid to upper 70s. -HEC
.LONG TERM...Tuesday through Friday... Ensemble guidance is in
good agreement that upper level flow will become more zonal
Tuesday as the shortwave moves to the east. Temperatures are
expected to rise back into the 80s for the lowlands. Ensembles
bring a final upper trough through the PacNW at some point Tuesday
night into Wednesday, though some uncertainty remains on the
exact timing. At this point, confidence is low on whether this
will produce showers or thunderstorms over the Cascades as the
positioning of the trough is farther north than this weekend`s,
which will keep upper flow more west to northwest - not as
conducive to shower/thunderstorm development. Expect breezy
westerly winds again through the Gorge and over the Cascades.
Ensembles indicate flow becomes more zonal once again for
Wednesday/Thursday into late week with temperatures slowly
rising to the upper 80s. WPC 500 mb cluster analysis hints at a
building ridge sometime late next week or weekend with about 55%
of the clusters indicating a fairly strong ridge right over the
PacNW and the other clusters showing the ridge axis farther
east with less ridging over the PacNW. Either way, temperatures
look to rise at least a bit more closer to the 90s for the
lowlands for the weekend with NBM indicating a 50-75%
probability of 90s. Early analysis indicates this would be a
short lived ridge with ensembles lowering heights after the
weekend. -HEC
&&
.AVIATION...Marine stratus continues to erode and will likely
fully dissipate within the next few hours across the forecast
area. HREF guidance continues to indicate about 60-80% chance for
IFR/LIFR cigs re-developing after 09Z Sunday for coastal locations
and a 70-80% chance for high-end MVFR/low-end VFR conditions to
return for inland locations around 10Z-12Z Sunday. Clearing for
inland locations expected 18Z-20Z Sunday.
There is a slight chance, around 10-20%, for thunderstorm
activity over the Oregon Cascades starting around 21Z Saturday
through 09Z Sunday.
Note: The KSLE observation is unavailable due to communication
issues. Dial in via phone and ground to air radio is still remains
available.
For detailed Pac NW aviation weather information, go online to:
http://weather.gov/zse
KPDX AND APPROACHES...VFR with slowly clearing skies. 70-80%
chance for high-end MVFR/low-end VFR conditions to return around
10Z-12Z Sunday. Clearing expected 18Z-20Z Sunday. /42
&&
.MARINE...High pressure offshore will slowly be replaced by a weak
low pressure system through the weekend. This will result in marine
stratus lingering through the daytime hours and re-constituting
overnight. However, high pressure returns early next week resulting
in a more typical summer pattern. Seas around 3 to 5 ft for the
weekend into early next week. Winds will increase on Sunday with
windwaves amplifying and becoming more of the dominate wave in the
background seas. /42
&&
.PQR WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
PZ...None.
&&
$$
www.weather.gov/portland
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Area Forecast Discussion
National Weather Service Pueblo CO
953 PM MDT Sat Jul 8 2023
.UPDATE...
Issued at 950 PM MDT Sat Jul 8 2023
Quick update to the forecast grids for cancellation of Severe
Thunderstorm Watch for much of the area this evening. The Watch
continues for Baca and Las Animas counties until 11 PM.
Incorporated latest obs grids.
&&
.SHORT TERM...(This evening through Sunday)
Issued at 244 PM MDT Sat Jul 8 2023
Key messages:
1) Severe thunderstorms possible this evening and overnight
across the plains.
2) Drier conditions with only isolated storms at most expected for
Sunday.
Moist and unstable air mass remains in place along and east of the
mountains this afternoon, with surface CAPE running in the 1-2k J/KG
range at most locations along and east of I-25. 0-6km shear
continues to be impressive as well, with values in the 50-60 kt
range over the plains. While early morning cloud cover has kept some
modest CINH in place and delayed the onset of convection slightly,
radar as of 2 pm was beginning to light up with convection, mainly
near the Palmer Divide and north of the Raton Mesa, where updrafts
have been given a topographically enhanced boost. Last few runs of
the HRRR seem to have a decent handle on convection, as main area of
storms east of Denver is expected to dive southward into sern CO
late this afternoon/this evening, supported by weak short wave
energy dropping southward through CO. Ahead of these storms, both
HRRR and NAMnest have trended toward development of some strong
discrete cells along the srn I-25 corridor, pushing them eastward
across the plains 22z-02z, before main area of convection/organizing
MCS drops south 02z-06z. Shear/buoyancy parameters suggest once deep
convection develops, supercells with large hail/strong winds are
likely, especially just east of the I-25 corridor. Activity will
persist past sunset on the plains, before most convection exits the
area after midnight. Over the mountains and interior valleys, any
convection late this afternoon and evening will be weak/brief, as
mid-level dry air continues to spread across the area.
On Sunday, moisture lingers across the plains, while mountains and
valleys stay dry and breezy. With mid-levels warming and surface
cold pool in place across the plains behind departing MCS, it
appears at this point we`ll have minimal convection across the area,
though will maintain some low pops in the Pikes Peak region where
various models have hinted at some brief pop-up showers/t-storms
late in the day. Max temps will remain warmer than average over the
mountains and valleys, while southeast plains stay relatively cool,
especially near the KS border where pool of rain cooled air
may keep readings in the 70s.
.LONG TERM...(Sunday night through Saturday)
Issued at 244 PM MDT Sat Jul 8 2023
Key Messages:
1) Dry and hot through about midweek. Isolated thunderstorms
possible.
2) More unsettled later this week.
Sunday Night-Tuesday...
An upper-level ridge will start to build in across the region as we
move into the work week, giving us increased temperatures and
relatively dry conditions, with some minor variations each day. For
Monday, temperatures will be well above normal for most of our area,
with the valleys and higher terrain sitting in the high-80s and the
plains largely in the 90s. Low level moisture will be somewhat
lacking everywhere along and west of the I-25 corridor, but
dewpoints do increase quickly heading out closer to the CO-KS border.
With some breezy south winds out east, a weak dryline is expected to
set up over our eastern plains Monday afternoon. With the moisture
axis coupled with a small disturbance moving through overhead,
scattered showers and thunderstorms will be possible, likely forming
along this axis before moving east into Kansas. The coverage and
severity of the potential storms will largely depend on where/how
that moisture boundary sets up, so we will see.
Tuesday-Wednesday look hot and mostly dry, with temperatures
increasing across the CWA. Current forecast does have highs close to
100 across parts of the eastern plains both days, and the valleys
will be in the 90s. Will have to be on the lookout for any heat-
related impacts and the need for potential highlights moving forward.
Thursday Onwards...
The ridge will continue to flatten out later this week, with a new
upper wave and an associated cold front currently slated to move
through sometime on Thursday. This will bring an uptick of
thunderstorm coverage late Thursday afternoon into evening, leading
to cooler and wetter conditions on Friday and into next weekend.
Models are still in disagreement on the timing, do more details will
have to be resolved closer to date.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 244 PM MDT Sat Jul 8 2023
At KCOS and KPUB, greatest risk of a tsra at both sites will be in
the 22z-02z time period, before bulk of convective activity pushes
east 02z-05z. MVFR to brief IFR stratus then returns after 05z-06z,
persisting until mid-morning on Sunday. Once clouds clear, expect
VFR Sunday afternoon, with lower chances of tsra than the past few
days, though some isolated storms will be possible over the higher
terrain north and west of KCOS.
At KALS, VFR the next 24 hrs with southwest to west winds gusting to
30 until 01-02z, then light winds expected overnight. Not quite as
windy on Sunday, though still some sw winds gusting 20-25 kts after
18z-19z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MOORE
SHORT TERM...PETERSEN
LONG TERM...GARBEROGLIO
AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service San Angelo TX
624 PM CDT Sat Jul 8 2023
...New AVIATION...
.SHORT TERM...
(This evening through Sunday)
Issued at 143 PM CDT Sat Jul 8 2023
Short range models continue to indicate a disturbance developing
across northern Texas overnight. The worst of the strong to
severe thunderstorm activity will likely remain off to the
north/northeast of our area (along the Red River).
A few isolated thunderstorms may develop in the Big Country on
Sunday morning, which is indicated in the HRRR and NAMNEST to
varying degrees. The southern extent of this activity is the main
question for this forecast. None of the models are really in good
agreement with this. If decent outflow boundaries can develop
there may be a bit more room for further development to the south.
However, this would be dependent on significant enough convection
developing across the Big Country for this to occur (not likely).
It`s worth a mention that the Storm Prediction Center has
included portions of Haskell and Throckmorton in a Marginal Risk
for severe weather with damaging winds being the main concern.
&&
.LONG TERM...
(Sunday night through next Friday)
Issued at 238 PM CDT Sat Jul 8 2023
...Heat Wave Returns Next Week.
Mainly a hot and dry forecast through the extended period, as high
pressure aloft dominates. A weak frontal boundary will be situated
just north of the area on Monday, with a disturbance aloft
tracking southeast across the Red River Valley by early evening.
Latest models show convection developing mainly north of the area
Monday afternoon and evening. Some of this activity could clip far
northern portions of the Big Country Monday evening, so will
retain 20 POPs this forecast cycle.
Of greater concern will be the development of another heat wave
across the region for the upcoming week. The upper high will expand
across the Desert Southwest next week, with heights rising over our
area by mid to late week. This will result in very hot temperatures,
with triple digit readings returning to all of the West Texas by
Tuesday, and persisting through the end of the week. The hottest
temperatures are expected Wednesday through Friday, where daytime
highs between 102 and 107 degrees can be expected each afternoon.
These hot temperatures will necessitate the issuance of Heat
Advisories and possibly Excessive Heat Warnings across the area
for the upcoming work week and possibly into next weekend.
&&
.AVIATION...
(00Z TAFS)
Issued at 609 PM CDT Sat Jul 8 2023
Satellite images and surface observations indicate a few mid to
high level clouds across extreme northern portions of the Big
Country early this evening. Otherwise...skies were clear across
the rest of the CWA. Expect VFR conditions to prevail across west
central Texas the rest of the evening into early Sunday morning as
the 500mb ridge across west Texas and northern Mexico continues to
provide subsidence across the CWA in general. A weak 500mb
shortwave trough is expected to move across the Texas panhandle
into Oklahoma late tonight. This will allow an MCS feature to
develop along a stationary frontal boundary across the TX/OK state
line overnight and thunderstorms may develop along the outflow
boundary from the MCS feature and move into the extreme northern
portions of the Big Country early Sunday morning. Expect MVFR to
IFR conditions with isolated thunderstorms in the vicinity of
local aerodromes...mainly across northern portions of the CWA.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 76 96 74 98 / 10 10 10 0
San Angelo 75 101 75 104 / 0 0 0 0
Junction 73 99 74 101 / 0 0 0 0
Brownwood 76 100 75 102 / 0 10 0 0
Sweetwater 76 99 74 100 / 0 10 10 0
Ozona 74 98 74 101 / 0 0 0 0
Brady 75 98 75 99 / 0 0 0 0
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...41
LONG TERM....24
AVIATION...61