Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/20/22
Area Forecast Discussion
National Weather Service Bismarck ND
924 PM CDT Tue Jul 19 2022
.UPDATE...
Issued at 923 PM CDT Tue Jul 19 2022
Only change for this evening was to extend POPs for a few more
hours, though the past few scans has shown the showers are now
starting to dissipate.
UPDATE Issued at 841 PM CDT Tue Jul 19 2022
Allowed the wind advisory to expire last top of the hour at 8 pm
CDT. Winds continue to decrease. No other updates.
UPDATE Issued at 642 PM CDT Tue Jul 19 2022
Gusty winds continue across western and central North Dakota
early this evening, especially for southwest and south central
areas of the state. Winds will remain gusty through 01Z (8 PM
CDT) based on latest BUFKIT soundings, and latest obs don`t show
any signs of letting up, so will extend the wind advisory for
another hour. Expected a rapid decrease then in wind speeds
between 01 and 02Z (8-9PM CDT) as the mixed layer decreases as the
sun begins to set. Will also maintain to low POPs over my east
through early this evening.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 332 PM CDT Tue Jul 19 2022
An upper level low located over northeastern North Dakota
continues to progress eastward into Minnesota. Convection
associated with the upper low continues to form, but is not
expected to be severe due to a lack of instability. Showers are
thunderstorms are expected to linger across north central and
northeastern North Dakota through the afternoon. A tight pressure
gradient from the upper low and subsidence on the backside of the
low has mixed advisory level winds to the surface. High winds are
expected to continue across the southern portion of North Dakota
through the evening. Skies will begin to clear west to east as the
low exits the region. This will lead to optimal radiational
cooling and pleasant overnight low temperatures in the upper 50s
to lower 60s.
Northwesterly flow becomes the dominant synoptic feature as an
embedded short wave is expected to makes it`s way through the
state tomorrow afternoon. In addition, afternoon mixing is going
to promote breezy conditions across the state. Instability
increase tomorrow afternoon as temperatures warm into lower 90s as
a weak low level thermal ridge builds over central South Dakota.
MU CAPE values near 1500j/kg with little to no CIN and +30kts of
effective shear could support an isolated strong to severe
thunderstorm. Some of the CAMs have convection initiating over
central North Dakota moving east of the CWA tomorrow evening.
However, some of the global models and the HRRR has little to no
convection. The big question for tomorrows convection is if the
forcing mechanism (short wave trough) is strong enough to initiate
storms.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 332 PM CDT Tue Jul 19 2022
Temperatures stay elevated across the region as a strong upper
level high sits over the Four Corners. This will lead to upper
level ridging over the Northern Rockies and northwest meridional
flow over the Northern Plains. Although, a low level thermal ridge
will build over the central plains increasing temperatures
throughout the plains. Temperatures are forecast to hoover in the
upper 80s to lower 90s for the central and southern part of the
state through the work week. Northwesterly flow and warm
temperatures will mix breezy winds to the surface during the
afternoon hours throughout the week.
Precipiation chances increase this weekend as an upper level low
is forecast to move through the Pacific Northwest dampening the
upper level ridge. The weekend system will decrease temperatures
into the upper 70s to lower 80s making it a pleasant weekend. The
pattern remains active in the extended as the region transitions
to a zonal pattern with another upper low expected next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 642 PM CDT Tue Jul 19 2022
Some low VFR/MVFR cigs remain possible early this evening for
KJMS. Otherwise the sky will trend SKC with VFR flight conditions
through Wednesday morning. An increase in clouds and a chance of
showers and isolated thunderstorms are then expected over the east
Wed afternoon, mainly impacting KJMS.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...NH
SHORT TERM...Johnson
LONG TERM...Johnson
AVIATION...NH
Area Forecast Discussion
National Weather Service Birmingham AL
827 PM CDT Tue Jul 19 2022
.UPDATE...
Evening Update.
&&
.SHORT TERM...
/Updated at 827 PM CDT Tue Jul 19 2022/
Rest of tonight.
No severe is expected for the rest of tonight as we slowly lose
the heat of the day. However, there may be a few showers and a
storm or two at times as bits of energy continue to traverse the
upper shortwave that extends from E TN and back into GA and AL. No
major changes were made to the lows for tonight, in the lower to
mid 70s as our airmass moderates. Some cloud cover is expected to
remain behind the convection tonight as well.
08
Previous short-term discussion:
/Updated at 129 PM CDT Tue Jul 19 2022/
Through This Afternoon.
An upper-level trough axis continues to shift east across the area
with more of a westerly flow pattern in the lower levels. This is
yielding another complex forecast in which the better large scale
ascent is shifting into Georgia, yet waves of energy aloft continue
to produce scattered showers and thunderstorms. Thermal boundaries
,leftover by early morning activity, are likely to contribute to
focused areas of additional scattered convection this afternoon with
highest PoPs generally near and east of I-65. Also watching
seabreeze activity across south AL which is generating a northward
advancing outflow boundary. This boundary will also serve as a focus
area for vertical growth across our southeast counties. Dewpoints in
the lower 70s and temperatures in the 90s is resulting in MLCAPE of
2500-3000 J/kg. DCAPE is also ranging from 1000-1200 J/kg, according
to RAP mesoanalysis, so any locally robust updrafts that develop
this afternoon could pose a risk of damaging wind gusts and/or a few
isolated instances of large hail in the strongest storms.
Tonight Through Wednesday.
Some lingering convection may continue overnight with PoPs
decreasing throughout the day tomorrow as the trough shifts further
east, and drier tropospheric moisture moves in from the west. Best
chances for isolated to scattered activity will focus across our far
eastern counties. With the expectation of more sun and less rain,
expect warmer temperatures and highs in the mid 90s, especially
west. Dewpoints will remain about the same, in the lower to mid 70s.
This will result in a few hours where heat indices may rise to or
just below 105 degrees, so a Heat Advisory will be in effect
tomorrow afternoon for much of our western counties.
86
.LONG TERM...
/Updated at 238 PM CDT Tue Jul 19 2022/
The previous forecast reasoning holds well with the forecast this
afternoon. It appears we may need a Heat Advisory for Thursday as
heat indices west of I-65 are in the 105-107 degree range and
lower east. Will evaluate another cycle and possibly add a day.
The forecast highs drop on Friday along with the heat indices.
This will not last beyond one day as the heat and humidity return
Saturday and beyond.
Severe weather remains a threat on Thursday and will keep the
wording and mentions the same. The moisture content in
combination with the enhanced updrafts, added mention of locally
heavy rain. Otherwise, rain chances continue each afternoon with
the highest pops Thursday and Friday.
75
Previous long-term discussion:
/Updated at 315 AM CDT Tue Jul 19 2022/
Thursday.
A strengthening low-level ridge is expected to build into the Gulf
of Mexico, generally extending from the Western Atlantic on Thursday
morning. This will coincide with a residual mid-level disturbance
departing to our south with mid- to upper-level ridging building
from our West. Southerly to southwesterly low-level flow will
continue across the Deep South as a shortwave trough/frontal system
moves south toward the Tennessee Valley. Higher theta-e content
will establish across the forecast area ahead of the advancing
surface trough/front by Thursday afternoon. The combination of
heat and humidity will likely tip the scales into Heat Advisory
criteria, particularly for areas along and west of I-65.
The moist, unstable boundary layer will also support strong to
severe thunderstorms Thursday afternoon and evening. With dewpoints
in the low to mid 70s and temperatures in the 90s ahead of the
advancing front, MLCAPE will exceed 3,000 J/kg at times. Forecast
soundings suggest lower mid-tropospheric RH values, as well as
decent mid-level lapse rates (~6.5 C/km). This will foster high
values of DCAPE whilst PWs remain elevated (1.8-2.1"). Despite
eff. bulk shear <20 kts, robust convection could develop with the
threat of wet microbursts early in the convective cycle, generally
before cold pool aggregation occurs later in the evening. Some of
the strongest updrafts could support marginally severe hail as
well. Nonetheless, the severe weather threat will be added to the
HWO in tandem with the ongoing/aforementioned heat. Outlying
convective scenarios could also lead to locally heavy rainfall,
but confidence is too low for HWO mentioning at this time.
Friday through Monday.
By Friday morning the surface front should have pressed farther
south. This will move more favorable moisture content/forcing for
afternoon convection south of I-20; it`s here where best PoPs
remain forecast. (It`s possible PoPs north of I-20 will need to be
decreased at some point.) We`ll need to keep an eye on convective
parameters for Friday as well. Either way, low-level ridging
further strengthens across the region on Friday, and mid- to
upper-level ridging becomes more prominent in the Southeast as
well, especially by Saturday as the persistent ridge out West
flattens out. This led to a decrease in PoPs and an increase in
diurnal temperatures. Low-amplitude ridging could persist in the
region through the end of the period with at or above average
temperatures. High temperatures in this timeframe are currently
forecast to be in the mid to upper 90s with 500 mb heights
increasing to ~595 decameters by the weekend. This could get us
into an extended period of Heat Advisory criteria Saturday
through Monday, and this will be added into the HWO.
40/Sizemore
&&
.AVIATION...
00Z TAF Discussion.
There are a few lingering showers/storms along/S of the I85
corridor that may affect MGM/TOI for the next 2-3 hrs. Otherwise,
precipitation chances should lower for the remainder of the
night after sunset. Another bit of energy associated with the
upper shortwave may yield some convection for ASN/ANB by mid/late
Wed afternoon, but overall chances are lower on Wed as the overall
upper shortwave weakens and pushes EWD.
08
&&
.FIRE WEATHER...
Southwesterly surface and transport winds at 5-10 mph will
continue with additional showers and thunderstorms possible
through this evening. Temperatures are forecast to increase
tomorrow, though with a decrease in overall afternoon convection
as the disturbance aloft moves to our southeast. Heat index values
likely increase to over 100 degrees during the afternoon. Minimum
RH values should remain above ~45%.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 72 93 74 94 71 / 30 30 20 60 50
Anniston 74 94 74 93 73 / 30 30 20 60 50
Birmingham 75 95 77 94 73 / 20 20 20 60 50
Tuscaloosa 76 96 77 96 74 / 10 10 20 50 50
Calera 75 94 76 93 74 / 20 20 20 60 50
Auburn 74 92 75 91 73 / 30 30 20 60 50
Montgomery 76 97 77 97 75 / 30 20 10 60 50
Troy 74 95 75 94 74 / 30 20 10 60 40
&&
.BMX WATCHES/WARNINGS/ADVISORIES...
Heat Advisory from 11 AM to 9 PM CDT Wednesday for the following
counties: Bibb...Blount...Fayette...Greene...Hale...Jefferson...
Lamar...Marengo...Marion...Perry...Pickens...Sumter...
Tuscaloosa...Walker...Winston.
&&
$$
Area Forecast Discussion
National Weather Service Denver/Boulder CO
846 PM MDT Tue Jul 19 2022
.UPDATE...
Issued at 843 PM MDT Tue Jul 19 2022
A few decaying thunderstorms over the Front Range at this hour
will gradually fizzle out as the evening wears on. After another
very warm day (Boulder tied its daily record of 100 F today),
temperatures will cool more than previous nights, with lows
dropping below 70 degrees for the metro area and closer to 60 F in
the plains.
No significant changes were made to the forecast this evening, as
it looks to be on track. Look to renewed scattered showers and
thunderstorms tomorrow after that, similar to Tuesday, will be
focused over the southern half of the Front Range, and along/south
of I-70.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 303 PM MDT Tue Jul 19 2022
Not much moisture in sight according to the mid level water vapor
imagery on GOES-16 as weak showers continue across the Palmer
Divide. Tonight, high based showers will dissipate across the
region and partly cloudy skies will remain. Temperatures will be
slightly cooler overnight compared the yesterday with most of the
eastern plains and urban corridor drops to the lower to mid 60s.
For the mountains and valleys, temperatures will dip into the mid
40s to lower 50s.
Upper level ridge pattern continue through Wednesday afternoon.
Heights continue to increase across the GFS/ECMWF as the 500mb high
pressure system sits over the Four Corners. Near the surface, a
stationary front develops which will drive moisture to the
mountains and valleys early Wednesday afternoon. Although, 700mb
levels from the HRRR and NAM trend dry with relative humidity
percentages near 15-20%. 700mb winds remain fairly weak through
Wednesday afternoon near 10-15kts will inhibit thunderstorm flow
for the mountains and valleys which may also limit development due
to weak shear. In this case, it is likely these thunderstorms
will struggle to sustain across the Front Range thus PoPs were
slightly decreased across the plains. The flash flood threat for
all burn areas remains limited.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 303 PM MDT Tue Jul 19 2022
Thursday, the upper level ridge shifts eastward resulting in height
rises and temperatures warming aloft. Highs will be a couple degrees
warmer than Wednesday with highs in the mid to upper 90s for the
lower elevations and 60s to 80s for the high country. The airmass
will be slightly drier with model soundings exhibiting well-mixed
profile with large temperature-dewpoint spreads at the surface in
the afternoon. Elevated to near-critical conditions are possible
over spotty areas of the plains (See Fire Weather section). With
marginal amounts of instability, there will be a low chance for
afternoon showers/thunderstorm; however, they are expected to be
lower in coverage. The better chances will be over the higher
elevations and south of I-70.
Friday, a weak trough pushes into the Pacific NW with the ridge
aloft building further over Colorado. In response, 700mb
temperatures likely rise into the 18-20C range supporting the
hottest day of the period. Ensemble guidance shows a good chance for
triple digits over the eastern plains and a healthy percentage of
members around/near 100 for Denver as well. A Heat Advisory is not
out of the question for the northeast corner and possibly the
plains. Moisture increases gradually into western Colorado with PW
values still around normal northeast Colorado. With marginal amounts
of instability, there will be a chance for scattered showers/storms,
with better chances over the high terrain and isolated chances for
the plains.
Confidence in the details of the pattern decrease for the weekend
and into early next week. Model solutions vary on the details of a
weak shortwave trough moving over the top of the ridge this weekend.
Ensemble guidance displays general agreement in the ridge flattening
and the return of above-normal moisture by Sunday which will
increase shower/storm coverage. Early next week, there is variance
in the details of another shortwave while a ridge builds in from the
west. Ensemble guidance also hints at a generally "cooler" pattern
with highs in the lower 90s (as opposed to upper 90s and low 100s)
Sunday through early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 532 PM MDT Tue Jul 19 2022
SCT TS continue to move E with a chance of -TSRA persisting in
vcnty of KDEN through ~02Z. TS outflow winds may produce brief
gusts 30-35 kts...otherwise anticipate prevailing SW/drainage flow
most of the evening and into overnight hrs. SFC boundary looks to
arrive 07-09Z with transition to NE winds for area terminals.
Expect speeds to become light and somewhat variable Wed AM,
although leaning to general N/NW winds albeit under 10 kt.
Renewed chance of SHRA or TS Wed PM, mainly 20-00Z, with breezy
outflow winds once again. VFR conditions expected to prevail
through the TAF period.
&&
.FIRE WEATHER...
Issued at 303 PM MDT Tue Jul 19 2022
Thursday, model soundings show well-mixed afternoon profiles with
plenty of dry air at the surface to support a dry environment. Min
relative humidity values drop into the low to mid teens with the
lower values over the plains. This is collocated with peak gusts
up to 20-25 mph. This will lead to spotty elevated to near
critical conditions for the plains. Confidence isn`t high in the
potential for critical fire weather conditions due to the limited
coverage and duration although, northern Weld County will see a
slightly higher chance. Fire weather conditions may be elevated
over portions of the plains Friday afternoon. Moisture increases
for the weekend reducing threat for fire weather.
&&
.HYDROLOGY...
Issued at 303 PM MDT Tue Jul 19 2022
Scattered showers and thunderstorm coverage remain south of I-
70 and near the Palmer Divide. This storms will produce limited
rainfall and wind gusts up to 45 mph. The threat of flash flood
through tonight remains limited. Wednesday, there is increasing
coverage from thunderstorms and PWATs increase to 0.60-0.80 inches
across the region. Therefore, all burn areas will continue in a
limited threat for flash flooding.
Lower precipitable water values and limited instability will keep
coverage of showers and thunderstorms lower Thursday and Friday.
This will keep the burn area flash flood threat limited/low.
Moisture increases over the weekend resulting in an increased threat
for flash flooding over the burn areas.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Rodriguez
SHORT TERM...AD
LONG TERM...Mensch
AVIATION...Rodriguez
FIRE WEATHER...Mensch
HYDROLOGY...Mensch/AD
Area Forecast Discussion
National Weather Service Burlington VT
946 PM EDT Tue Jul 19 2022
.SYNOPSIS...
Isolated thunderstorms will move across Northern New York this
evening, these storms may produce strong gusty winds. Heat and
humidity will be with us through the next several days, peaking
on Wednesday and Thursday when heat index values will reach into
the low 90s in many locations. A heat advisory is in effect for
the Saint Lawrence and Champlain valleys from noon to 8 pm.
Widespread showers and thunderstorms will sweep eastward on
Thursday, followed by more chances of showers and thunderstorms
over the weekend.
&&
.NEAR TERM /THROUGH WEDNESDAY NIGHT/...
As of 943 PM EDT Tuesday...Areal coverage acrs the SLV and
western dacks has decreased with the loss of sfc heating and
developing areas of CIN. However, RAP analysis still shows
pockets of instability with additional threat for isolated
shower/storm possible thru early Weds, so have kept schc pops
going. Also, did some tweaking to the temps, as BTV is still 80F
as of 930 PM, while many values are still holding into the 70s.
Have bumped temps up a degree or two, especially urban heat
islands of the CPV. Rest of fcst in good shape.
Previous discussion follows.
Will have isolated thunderstorms move into the Saint Lawrence
valley and Northern Adirondacks early this evening, dying down
after sunset associated with a secondary cold front pushing into
the region. This front will not bring a large air mass change
though, and overnight low temperatures will remain quite warm
with mins mainly ranging through the 60s. Surface and upper
level ridges build over our region overnight. Think that we
could see some fog develop as the ground is quite situated after
recent heavy rainfall. There remains some question though as
the winds aloft could preclude fog formation.
With surface and upper level ridging remaining over our region,
Wednesday will be quite hot with high temperatures ranging
through the 80s into the lower 90s. A heat advisory is in effect
for the St Lawrence and Champlain valleys from noon to 8 pm.
Heat indices will reach the 95 to 100 range in the afternoon.
Will have a slight chance for showers Wed afternoon with surface
instability in place, but we may be capped.
On Wednesday night aforementioned ridges will slide eastward,
and next system which will impact our region mainly on Thursday
will approach from the Great Lakes region. Will have chance for
showers beginning early Thursday morning in our Northern New
York zones. Overnight lows will be even more mild than tonight
with lows not making it below 70 in parts of the region, with
humid conditions continuing as well.
&&
.SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/...
As of 343 PM EDT Tuesday...Main concern for Thursday is locally
strong to severe thunderstorms, especially during the afternoon
and early evening hours. Could be a rather widespread
convective event, and will continue to monitor trends carefully.
Pre-frontal trough combined with mid-level cyclonic flow/height
falls with approaching H7-H5 trough will coincide with peak
daytime heating based on 12Z NWP guidance suite. Looking at
850mb theta-e ridge in place across VT with 850mb temps
generally +18C to +20C. This should contribute to valley highs
near 90F. Boundary layer dewpoints near 70F will contribute to
very unstable conditions, with SBCAPE 2000-3000 J/kg and deep
layer shear of 30-40kts. Should see widespread convective storms
in the afternoon with embedded small scale bows and possible
supercells given expected conditions. Agree with SPC Day 3
slight risk, and have included enhanced tstm wording for
Thursday afternoon. Have also boosted PoPs to 70-80% during the
mid-late aftn. Lastly, should see heat index values 90-95F in
advance of convective storms.
Trailing cold front approaching from sern Ontario should bring
lingering showers along the boundary through the evening hours,
followed by clearing later Thursday night. May see some patchy
fog development in the favored valley areas after midnight,
especially in locations seeing heavier rainfall totals. Lows
Thursday night generally in the low-mid 60s.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 343 PM EDT Tuesday...Cold frontal passage Thursday night
will bring somewhat lower humidity levels for Friday and
Saturday (dewpoints in the lower 60s). That said, only modest
change expected in temperatures with highs 85-90F both Friday
and Saturday. Zonal mid-level flow and overall lack of forcing
should keep Friday dry, but trend toward slightly cyclonic mid-
level flow on Saturday may allow for a few afternoon
thunderstorms, especially across the northern half of the
forecast area. Included 20-30% PoPs for the afternoon and early
evening hours on Saturday. A stronger shortwave trough brings
the potential for scattered showers and thunderstorms headed
into Sunday afternoon (PoPs 30-40%), with highs in the lower
80s. Following this shortwave trough, may see a trend toward
more seasonable temperatures and lower humidity levels headed
into Monday-Tuesday next week.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Through 00Z Thursday...A few decaying thunderstorms are
traversing the Adirondacks, and activity should dissipate over
the coming hour and with winds quickly trending light and
variable. Mainly VFR overnight, with some clouds lingering from
the convection, but otherwise, mainly high clouds. There should
be enough clearing that some fog should develop, and with
recent widespread rain, think we should see some fog even beyond
the climatologically favored spots and have mention of it at
KSLK, KMSS, KEFK, and KMPV between about 07Z and 12Z. Thereafter,
winds increasing to about 5 knots. Cumulus should develop with
bases about 5000 to 7000 ft agl after 15Z.
Outlook...
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. Chance SHRA, Chance TSRA.
Thursday: VFR. Likely SHRA, Chance TSRA.
Thursday Night: VFR. Slight chance SHRA.
Friday: VFR. Slight chance SHRA, Slight chance TSRA.
Friday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Saturday: VFR. Slight chance SHRA, Slight chance TSRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...Heat Advisory from noon to 8 PM EDT Wednesday for VTZ001-002-
005-009-011.
NY...Heat Advisory from noon to 8 PM EDT Wednesday for NYZ026>028-
035-087.
&&
$$
SYNOPSIS...Neiles
NEAR TERM...Neiles/Taber
SHORT TERM...Banacos
LONG TERM...Banacos
AVIATION...Neiles
Area Forecast Discussion
National Weather Service Grand Rapids MI
1121 PM EDT Tue Jul 19 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 1122 PM EDT Tue Jul 19 2022
I am still thinking the severe storm risk through sunrise is
minimal at best. The short story for why is that we are in the
right exit region of the polar jet core that is driving this
current storm system. As a result, the low level jet speed max is
over the upper peninsula of Michigan overnight. That puts our
entire CWA in the speed divergence region of the low level jet
which in not a good place for severe storms. There is also very
dry air above 500 mb which creates a poor environment for storms
to develop.
There is, however, a chance for rain showers due to the moist air
between 850 and 500 mb near and just ahead of the surface cold
front. There is decent surface convergence with the front itself
and there is some upper divergence over the front between 500 and
300 mb. That will continue until the front gets to the western
shore of Lake Michigan towards morning. This results in a line of
rain showers, which is shown by both the 00z HRRR and the 00z
HREF over central and eastern WI after midnight. That line of
showers moves into western lower Michigan just before 8 am
Wednesday morning.
As I write this, there are developing stronger storms over
extreme northwest WI and the extreme western section of the
Michigan upper peninsula. Overnight,where SPC has their slight
risk, there is the greatest instability. It is that area, if any,
that would receive severe storms tonight. The biggest threats
being large hail and damaging winds.
My spin is there will be a building line of convection ahead of
the cold front, that there is already, but that the convection
will build father south after midnight. However, due to the dry
air above 500 mb, the storms will not be able to grow. That would
then limit the convection to just rain showers. There could be
enough instability north of Little Sable point for a few
thunderstorms.
South of Little Sable Point, rain showers are more likely, with
locally heavy rain showers possible. The 12 hour QPF from the HRRR
has consistently shown less than 0.10 inches south of Muskegon.
In fact the 6 hour HREF probability- match mean (PPM) shows
nothing over .10 inches through 8 am, south of Traverse City. The
ensemble max shows the .10 north of Muskegon as per the HRRR.
So the bottom line is, expect isolated thunderstorms with
numerous light rain showers west of US-131 and north of Little
Sable Point between midnight and sunrise. Between Holland and
Muskegon expect scattered light rain showers between 3 am and 8
am.
Wednesday, during the day, we see the troposphere fold eastward
associated with the upper low moving across Michigan. This
effectively pushes the better deep lift east of our area so the
stronger storms will be well east of our CWA.
&&
.DISCUSSION...(This evening through next Tuesday)
Issued at 216 PM EDT Tue Jul 19 2022
...Risk for some thunderstorms tonight...
Models are generally showing a low level jet moving in from the
west after midnight. This feature draws in moisture from the
southwest which leads to elevated instability. The region north of
a Muskegon to Grand Rapids line has the best potential for storms
as they will be closer to the nose of the low level jet and also
see the most instability. In addition the arrival of a stronger
mid level wave leads to height falls. The best height fall occur
north of the CWA. If thunderstorms can get going...damaging winds
would be the main risk given the stronger wind fields advertised
by the guidance. Deep layer shear is shown to be over 35 knots for
northern parts of the CWA...especially after midnight. SPC has
this area in a marginal risk for severe thunderstorms.
...Gusty winds for Wednesday Afternoon...
The mixing height deepens considerably Wednesday afternoon. At the
same time...models are strengthening the winds at the top of this
mixed layer. Based on Bufkit overviews...most models show inland
areas mixing into the 30 knot range of winds. These winds are also
supported by the ensemble guidance. These winds may be enough to
generate isolated power outages. The incoming 12z ECMWF is showing
gusts around Mount Pleasant and Lansing topping 40 mph by 19z
Wed. If this trend of stronger winds continues...we may indeed see
some inland wind gusts values approaching advisory criteria for a
few hours. The mixing height diurnally decreases in the evening
which will support diminishing winds.
...A marginal risk for severe thunderstorms near Lansing and
Jackson Wednesday afternoon...
A cold front will push eastward through the region late Wednesday
morning into the early afternoon hours. It is possible that
enough warm and moist air advection could occur to support a few
storms to get going. Locations well inland stand the best chance
to see isolated/scattered storms. It is worth noting that most
models don`t generate convection Wednesday afternoon until the
front clears Lansing and Jackson. The NAM and NAM 3km models
generally show much higher surface dewpoints compared to the
other models Wednesday afternoon...which leads to considerably
greater instability. The deep layer shear is supportive for
organized convection...so if storms do get going...they will need
to be monitored closely.
...Thunderstorms possible over the weekend...
Models are showing the mid to upper level flow becoming zonal with
the thermal gradient tightening up. A stronger upper level jet
develops over the Great Lakes Region Saturday into Sunday with
some upper level divergence noted. At the same time a 30 to 40
knot low level jet noses into MI...mainly Saturday night...which
advects in increasing moisture. All this leads to instability and
an increased risk for thunderstorms...perhaps widespread. We will
continue the trend of increasing POPs for this period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 808 PM EDT Tue Jul 19 2022
Overall I am thinking solid VFR through Wednesday. While it is
true the surface storm moving through Michigan Wednesday is
unseasonable strong (991 mb low) and that will mean strong winds
both surface and aloft, the system is seriously moisture staved.
It would seem we could see some showers (maybe a thunderstorm)
move through the western TAF sites in the 10z to 14z time frame
with the cold front, those showers are expected to dissipate once
they get east of US-131. Thunderstorms are expected to develop
but more likely east of I-75 (Detroit area)late in the day.
The biggest impact this system will have on aviation in southwest
Michigan is the strong winds. Once the cold front comes through
expect winds should sustain 15 to 20 knots with some gusts near
35 knots.
&&
.MARINE...
Issued at 216 PM EDT Tue Jul 19 2022
The south to southwest winds will continue to increase this
evening into tonight generating higher waves. Areas to the north
of Holland will likely see wave heights above 4 feet with values
over 6 feet possible Wednesday morning. The hazardous conditions
will persist through Wednesday but gradually improve Wednesday
night. We will maintain the current swim and boating headlines as
a result.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 2 AM EDT Wednesday through
Wednesday evening for MIZ056-064-071.
Beach Hazards Statement through Wednesday evening for MIZ037-043-
050.
LM...Small Craft Advisory until 8 PM EDT Wednesday for LMZ847>849.
Small Craft Advisory from 2 AM to 8 PM EDT Wednesday for
LMZ844>846.
&&
$$
UPDATE...WDM
DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS
Area Forecast Discussion
National Weather Service Huntsville AL
758 PM CDT Tue Jul 19 2022
...New NEAR TERM...
.NEAR TERM...
(Tonight)
Issued at 758 PM CDT Tue Jul 19 2022
Convective cells continue to develop across north GA but have yet
to rematerialize over north AL of middle TN as earlier clouds and
morning convection stabilized the atmosphere. Convective
instability was rather strong just to our west over the mid South
with MLCAPE values 3000-4000 J/kg. This is also where moisture
transport is beginning to increase in west TN and north MS. This
should continue to increase overnight as the west-southwest LLJ
accelerates to 25-35kt. HRRR and the 12Z ARW indicated convection
will develop later this evening and overnight in the moisture
transport axis over western and middle TN, then drop southeast
into southern middle TN and northeast AL. With this in mind, will
keep a chance category PoP across southern middle TN and
northeast AL.
&&
.SHORT TERM...
(Wednesday through Friday)
Issued at 312 PM CDT Tue Jul 19 2022
Cloud cover and isolated to scattered showers and thunderstorms
should linger near this weakening boundary through the morning
hours. This will hopefully keep highs from reaching the 97 to 99
degree range in NW Alabama, given the forecast 925 mb temperatures
in some guidance. Still expect highs to climb into the 95 to 97
degree range near and west of the I-65 corridor though. With
moisture pooling along that boundary in the morning to early
afternoon hours, expect the combination of humidity and air
temperatures to push heat index values into the 105 to 109 degree
range. Therefore, the Heat Advisory was continued from 11 AM through
6 PM on Wednesday. If temperatures reach the 98 or 99 degree range
tomorrow, a excessive heat warning may be needed for portions of
northwestern Alabama.
Highs don`t look too different on Thursday, as models show more
cloud cover ahead of an along a new weakening frontal boundary
that moves southward from southern middle Tennessee into northern
Alabama. Isolated to scattered showers or storms could occur along
it, but not sure forcing will be very good and timing wouldn`t
favor a lot of activity given lack of shear. Most guidance pushes
this front to near or south of the Tennessee River by noon or so
on Thursday. How much redevelopment/coverage will occur along the
front into northern Alabama is questionable given the movement of
the front. However, some isolated to scattered convection could
refire in the afternoon into the early evening hours. Given
forecast instability, a stronger storm producing damaging winds
cannot be ruled out, but is very uncertain.
In addition, pooling of moisture ahead of the front and continued
925 mb temperatures near the front in the 27 C to 29 C degree
range could again produce heat index conditions reaching 105 and
109 degrees. However, if highs are cooler than expected due to
cloud cover, this may change.
A return of much drier air is expected on Friday behind the front.
Isolated to widely scattered convection cannot be ruled out south
of the Tennessee River. Air temperatures will not be much lower
though, still reaching the 95 to 97 degree range near and west of
the I-65 corridor.
&&
.LONG TERM...
(Friday night through Tuesday)
Issued at 312 PM CDT Tue Jul 19 2022
Friday night we expect lows only to drop into the upper 60s to
lower 70s under clear skies. Highs in the lower to mid 90s will
continue into early next week. The center of the upper ridge will
remain more to our west and east through that time, with a
weakness in the ridge remaining over the area. This will push heat
index values at least close to 105 degrees through that period.
&&
.AVIATION...
(00Z TAFS)
Issued at 520 PM CDT Tue Jul 19 2022
VFR flight weather conditions are expected during the period with
the exception of conditions in and near TSRA. Isolated to
scattered TSRA are possible this evening and overnight in southern
middle TN and northeast AL, mainly northeast of KHSV. Within
these areas, temporary IFR or MVFR conditions are possible.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...Heat Advisory from 11 AM to 6 PM CDT Wednesday for ALZ001>009-
016.
TN...Heat Advisory from 11 AM to 6 PM CDT Wednesday for TNZ076-096-
097.
&&
$$
NEAR TERM...17
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...17
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1048 PM CDT Tue Jul 19 2022
.SHORT TERM... (Through Late Wednesday Night)
Issued at 250 PM CDT Tue Jul 19 2022
Latest deterministic and ensemble model guidance keeps upper level
ridge axis to our west with trough to our east in the short term. So
we will remain in weak northwest flow aloft with a vigorous upper
level shortwave over the Northern Plains sliding east southeast
through the Great Lakes Region over the next 24 to 36 hours. This
will drag an associated cold front through the forecast area. The
main energy and moisture will stay well north of the region so it
will be a dry frontal passage. Therefore on Wednesday there will
be a wide range of temperatures across the region with highs
ranging from the upper 80s north to between 100 and 103 across the
far south. Dewpoints will remain in the mid 60s to mid 70s
through midday tomorrow. Then latest NAM, GFS and RAP forecast
soundings are still indicating decent mixing to at least 850mb
across central Missouri, as well as the Ozarks during the
afternoon hours, so expect the higher dewpoints in this area will
lower into the low to mid 60s. However with highs in the mid 90s
to near 103, will still see heat index values between 100 and 109
degrees. The highest heat index values will be over Reynolds, Iron
and Madison counties topping out between 105 and 109 degrees. So
have issued a Heat Advisory for these 3 counties for Wednesday
afternoon/early evening.
As for low temperatures through the short term, it will remain
rather mild tonight with lows in the upper 60s to upper 70s. Then on
back side of the cold front, lows Wednesday night will be near
normal in the mid 60s to low 70s.
Byrd
.LONG TERM... (Thursday through Next Tuesday)
Issued at 250 PM CDT Tue Jul 19 2022
Even though a surface ridge will build in over the region early on
Thursday, little to no CAA associated with it. Therefore highs will
still be above normal Thursday. Beyond Thursday, latest WPC cluster
analysis continues to indicate good agreement among the ensembles
with the upper level ridge building eastward through the weekend.
This will usher in a strong southwesterly flow across the region
with well above normal temperatures. Some deterministic and
ensembles are hinting that the upper ridge will flatten later in the
weekend, allowing the first in a possible series of upper level
shortwaves to slide east through the Great Lakes region. This would
drag a cold front down into Missouri and Illinois with increasing
chances of showers and storms, especially by Monday and Tuesday.
With the stronger upper level ridge overhead Friday and Saturday,
highs will top out between 95 and 105 both days. This extreme heat
combined with dewpoints in the 60s to low 70s could create heat
index values in excess of 105 at a number of locations, so will
need to keep an eye on this trend for possible heat headlines.
Still some question as to temperatures and heat index values on
Sunday depending on where the front will be.
Byrd
&&
.AVIATION... (For the 06z TAFs through 06z Wednesday Night)
Issued at 1039 PM CDT Tue Jul 19 2022
VFR conditions will persist through the period.
Few/scattered high clouds will pass overhead in the first few
hours of the TAF period, which is remnant of a convective feature
out of the central plains late Monday night into early Tuesday
morning. There is also a brief, but subtle wind shift out of the
southeast ahead of this. Given winds are well under 10 knots at
most locations, this will have relatively little impact as surface
flow quickly returns out of the south.
A cold front is currently positioned over interior sections of
Iowa and entering northwest Missouri. Other than the veering
surface flow, the front will pass through relatively quiet.
Maples
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 78 97 72 97 / 0 0 0 0
Quincy 72 88 67 92 / 0 0 0 0
Columbia 74 96 69 100 / 0 0 0 0
Jefferson City 75 98 70 101 / 0 0 0 0
Salem 74 95 69 92 / 0 0 0 0
Farmington 74 100 69 96 / 0 0 0 0
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
736 PM EDT Tue Jul 19 2022
.UPDATE...
Issued at 736 PM EDT TUE JUL 19 2022
Convection upstream of Upper Michigan this evening has largely been
held in check thanks to some capping in the lower-levels. Rapid
refresh models continue to cut back on both timing and coverage
through the evening hours, with 22Z HRRR still suggesting some iso
tsra across wern Gogebic around 00Z, which seems a little excited
given latest sat trends; however, there is some vertical growth
beginning to show along a line from Superior to just west of Minong
(which lines up somewhat with HRRR if these blips continue to grow).
With diurnal heating ending, sfc-based threat of thunderstorms are
beginning to look less likely with sfc front back across the MN/WI
border. Model soundings do suggest some elevated MUCAPE to work with
as temps aloft cool with low pressure moving overhead. That could
still bring a marginal hail threat as effective shear remains on the
lower end.
&&
.SHORT TERM...(This evening through Wednesday)
Issued at 347 PM EDT TUE JUL 19 2022
Severe weather that produced large hail last night tappered off this
morning in association with the warm front of an approaching low. A
few showers and storms did linger through the day as temperatures
mainly reached the 70s, and currently, some showers are moving
through eastern Upper Michigan. As a cold front moves in from the
west tonight, some hail and strong winds will again be possible.
Overnight, 0-6 km bulk shear of around 30 knots and ML CAPE of 1000
to 1500 J/kg is expected.
.LONG TERM...(Tonight through Tuesday)
Issued at 327 PM EDT TUE JUL 19 2022
Persistent clouds, strong capping, and limited low level forcing
have kept convection at bay today. There still appears to be a
window for at least a broken line of convection along the surface
front as it pushes east this evening. While frontal convergence is
unimpressive...cooling aloft as the upper low approaches may be
enough to fire some thunderstorms from the Arrowhead of MN into
western Lake Superior. If storms fire, there`s still enough wind
shear for a few stronger storms. Most hi res guidance shows storms
dying off pretty quickly after sunset so confidence isn`t very high
as to how far east storms will get. The further south you go the
rain chances will be less.
Upper low will move right across the U.P. on Wednesday. Expect a few
scattered showers to linger through the day over inland areas but
they should be mainly light. Drier air moves in later in the day as
ridging pushes east.
Northwest winds could gust up to 25 knots behind the front over Lake
Superior Wednesday night into early Thursday...expect a moderate to
high swim risk to exist for Alger County beaches east of Munising
overnight Wednesday through about midday Thursday.
Beyond Wednesday, it looks like generally tranquil and seasonable
weather for late week through the weekend. Weak shortwaves passing
just south of the area late Friday and again Saturday afternoon may
trigger a couple of showers south, but most will remain dry.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 722 PM EDT TUE JUL 19 2022
An area of low pressure moving across northern MN into Ontario this
evening will drag a cold front across Upper Michigan tonight through
tomorrow. This will bring gusty southerly winds tonight, that will
gradually diminish and veer to the SW tonight and WNW by tomorrow.
VFR conditions should prevail through much of the period; however,
there is a chance for some MVFR cigs late tonight through tomorrow
morning due to abundant low-level moisture. CMX could see some
marine fog advect across the terminal tomorrow morning, but
confidence is too low to include in TAF at this time.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 327 PM EDT TUE JUL 19 2022
Gusty south winds over the eastern Lake tonight will turn westerly
on Wednesday behind a cold front. Expect west and northwesterly
winds gusting up to 25 knots from late Wednesday afternoon through
the morning hours on Thursday. Beyond that, expect winds less than
20 knots across the Lake through the weekend.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Beach Hazards Statement until 10 PM EDT this evening for MIZ014.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
UPDATE...JAW
SHORT TERM...KT
LONG TERM...MZ
AVIATION...JAW
MARINE...MZ