Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/06/24
Area Forecast Discussion
National Weather Service La Crosse WI
1022 PM CDT Sat Oct 5 2024
.KEY MESSAGES...
- Low (20 to 30%) potential for a shower or thunderstorm in
central and north central Wisconsin late this afternoon into
this evening. If a thunderstorm does in fact occur, a
localized strong to severe gust cannot be ruled out.
- Decent to very likely (30-90%) probability temperatures fall
enough Monday morning for potential frost formation across
much of the area.
- After a cool and breezy Sunday, temperatures climb back above
normal through the work week. The chance for precipitation is
at or close to zero each day.
&&
.UPDATE...
Issued at 648 PM CDT Sat Oct 5 2024
Local 23Z surface analysis really showing some action across
the area. Low pressure is located right near La Crosse WI with a
N->S oriented cold front roughly from west of Winona to near
Waterloo Iowa shifting east rapidly. Vigorous pre-frontal, low-
level warm advection is found over WI, with cold advection over
much of MN/IA. Wind gusts on the cold front have been stronger
than the afternoon pre-frontal gusts with gusts of 30-39mph
right on the front. With some cooling with sundown and
stability, expecting the gusts to be a bit lower as the front
rolls through western/central WI early this evening.
An axis of instability exists pre-frontally but there is also
stout capping. The only weakness in the cap sweeps through
northwest into northcentral WI along the front. Some TSRA
activity is in this area near Hayward at 2330Z, with other
weaker showers to the south. Low storm chances are mainly
north/northeast of La Crosse, and right on the front where
convective inhibition goes to near zero. Otherwise, the area is
capped.
A break in the winds occurs for most of the overnight until a
stronger cold front arrives in the pre-dawn hours with another
moderate-strong cold advection signal. Soundings dont flip to
steep lapse rates right on the front but do shortly after, with
gusts coming up early areawide...30-40 mph with breakfast. The
low-level wind field increases with model consensus of ~40 kts
only 4kft AGL in the morning. The entire day will be breezy, but
that morning period has the highest gust potential.
&&
.DISCUSSION...
Issued at 210 PM CDT Sat Oct 5 2024
Windy Saturday afternoon with low potential for evening showers and
storms
The modest downward trend in top end winds seen in guidance over the
past 1-2 days has been borne out, with top wind gusts generally
around 30-35 mph so far early this afternoon despite mostly clear
skies. Additionally, RH values have fallen less than the most
aggressive guidance suggested it would, largely courtesy of modest
southerly moist advection. Have thus refrained from upgrading part
of the ongoing SPS to a Red Flag Warning. As for wind expectations
this afternoon, progged soundings do still suggest a small window
for a 40 mph gust or two west of the Mississippi River valley during
the 3 to 5 pm time frame but, with things having underachieved thus
far, have also refrained from issuing a Wind Advisory.
Moving ahead to this evening, as the upper low over Lake Winnipeg
and attendant cold front advancing over western Minnesota progress
eastward, a few showers and thunderstorms could presumably occur
east of the Mississippi River where marginal 700/850mb moisture may
be present enough to overcome capping in the 500-650mb layer. While
the 05.12z HREF suggests a decent (30-60%) chance for precip along
and north/east of I-94, the trend in the HREF has been downward over
the 3 runs that cover through tonight. Additionally, most HRRR runs
suggest the cap will not be overcome. Given this HREF trend and
guidance assimilating the latest obs remaining pessimistic, have
continued to shift PoPs toward consensus of CAM guidance, yielding
numbers in the 20-30 percent range, restricted to areas along and
north/east of I-94. As for hazards, expected high cloud bases atop a
fairly well-mixed boundary layer continue to suggest that strong to
perhaps severe gusts could occur with any thunderstorms that do
manage to develop.
Frosty Monday
As the aforementioned upper low barrels eastward to Hudson Bay,
surface high looks to develop in IA in the wake of this feature.
This should lead to mostly clear skies and light winds, causing
surface temperatures to tumble Sunday night into Monday. 05.12z HREF
and NBM indicate much of the CWA has a 30 to 90 percent chance to
fall at or below 36 degrees with best chance for this east of the
Mississippi River, setting the stage for potential frost formation.
Will need to monitor this closely as most areas have yet to see
frost this fall.
Warming trend and lack of precip next work week
Medium range guidance continues to point toward upper ridging
developing over the central CONUS with our forecast area mainly
under northwesterly flow aloft. This should serve to keep things
free of precip as temperatures creep back upward into the 70s and
even 80s after our cool Sunday.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1021 PM CDT Sat Oct 5 2024
VFR is expected. Winds increase aloft overnight with LLWS
indicated with 40kts at 2-3kft. A secondary cold front will move
through in the 09-12Z time period making for a gusty Sunday
morning after sunrise with the potential (20%) for higher gusts
than currently are in the TAFs. Winds will remain roughly
18G28kts for the afternoon Sunday before diminishing at sunset.
&&
.FIRE WEATHER...
Issued at 350 AM CDT Sat Oct 5 2024
This afternoon`s fire weather risk is driven heavily by winds.
Southerly winds increase through the morning and by midday will
be sustained around 20 to 25 mph, gusting upwards of 30 to 40
mph. The higher gusts in this range will be west of the
Mississippi River. However, these stronger winds will advect
increasing amounts of moisture northward, raising dewpoints into
the 50s and preventing afternoon relative humidity values from
falling much below 30-45 percent. The lowest humidity values
will also be west of the Mississippi River where temperatures
should climb well into the 80s. The lack of recent rainfall has
resulted in Build Up Indices west of the Mississippi River
pushing 80-100, near critical dryness levels. The GFDIAg values
also support that any harvest-ready fields could be susceptible
to fires. A cold front sweeps through this evening, quickly
switching the wind direction to the northwest for the night.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
UPDATE...Baumgardt
DISCUSSION...Ferguson
AVIATION...Baumgardt
FIRE WEATHER...Skow
Area Forecast Discussion
National Weather Service Burlington VT
1029 PM EDT Sat Oct 5 2024
.SYNOPSIS...
After a beautiful day temperatures will quickly cool off tonight
with areas of patchy fog developing after midnight. Lows will range
from the upper 20s to lower 40s across the region with some patchy
frost possible in the colder valley locations away from Lake
Champlain. Another mild and dry day is anticipated on Sunday, before
a cold front produces scattered showers Sunday evening into Monday.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 1022 PM EDT Saturday...Temperatures have been cooling down
rapidly this evening. Many areas have already dropped more than
20 degrees and temperatures will continue to steadily fall. Some
clouds over Quebec`s Eastern Townships are attempting to drop
into the Northeast Kingdom, and skies could turn partially
cloudy there as the night goes on. Fog is just beginning to
form in a few of the climatologically favored areas and it will
become more widespread as the night progresses.
Previous Forecast...Fcst focus tonight wl be frost and fog
potential acrs parts of our cwa. Water vapor shows a lobe of
extremely dry air aloft advecting acrs our cwa, while 1028mb sfc
high pres builds into our fa. This dry air aloft wl result in clear
skies tonight with temps quickly dropping after sunset due to light
winds and dwpts in the 30s. These ideal radiational cooling
conditions wl result in the coolest temps of this fall season acrs
many locations with lows in the upper 20s to lower 40s. Have
followed previous fcster lead and trended toward the 10th NBM for
lows with some blending of the latest MAV. This supports near 27F at
SLK to 43F here at BTV. Areas of patchy frost is likely acrs the
dacks/nek, but our frost program has ended. Also, some patchy frost
in a few selected valleys of Washington/Lamoille and Orange Counties
is possible tonight, along with localized valleys of eastern
Chittenden and Franklin counties, but coverage and duration is not
enough for an advisory attm. Have fog in the favored climo valleys,
but delayed development until after midnight. Sounding data also
supports fog at EFK too, due to lingering llvl moisture and
sharp/shallow inversion.
After a chilly start on Sunday morning, temps wl quickly warm with
developing southerly flow ahead of our next cold frnt. GOES-16 vis
satl upstream imagery shows some mid lvl clouds associated with weak
warm frnt type over the western Great Lakes, while ribbon of deeper
moisture with boundary is over the northern Plains. This moisture
and dynamics wl be approaching our western cwa by 00z Monday with
increasing clouds and showers developing. Have utilized a
combination of NAM3KM and 12z HRRR composite reflectivity progs for
timing of precip moving from west to east acrs our cwa on Sunday
night. Also, have bumped winds up aft 18z on Sunday, as soundings
support some mixing of winds of 20 to 25 knots with potential
localized higher gusts overnight Sunday with frontal boundary.
Finally noted a weak axis of elevated instability with boundary on
Sunday evening, so a rumble or two of thunder is possible,
especially given the robust dynamics and associated synoptic scale
height falls. Highs on Sunday warm into the mid 60s to lower 70s
with lows Sunday night in the mid 40s to mid 50s.
&&
.SHORT TERM /MONDAY NIGHT/...
As of 317 PM EDT Saturday...Additional rain showers are expected
through the first half of Monday with a strong cold front continuing
to work across the North Country. Additional rainfall amounts during
the daylight hours will be less than two tenths of an inch across
eastern Vermont with little to northing across western Vermont and
northern New York. Dry air is expected to filter into the region
rapidly following the frontal passage which will likely aid in
bringing gusty northwesterly winds to the area. Very inefficient
heating is expected on Monday giving strong cold air advection in
the low to mid-levels with highs only topping out in the mid 50s to
mid 60s. As dry air continues to filter into the region overnight
Monday, temperatures are expected to drop to some of the coolest
values seen this fall with lows dropping into the upper 20s in the
typical cold hollows to mid 40s in the wider valleys. Fog isn`t
expected Monday night as enough low level flow should dampen the
possibility of fog settling into the valleys.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 317 PM EDT Saturday...We`ve got an exceptional week of weather
on tap, especially for those visiting to see the fall foliage.
Temperatures through the week are expected to be at or just above
seasonal normals for afternoon highs and at to just below normal for
morning lows. A reinforcing shot of cold air is expected to descend
out of Canada on Wednesday which could bring a few showers to the
region but the lack of any appreciable moisture should keep the
shower activity rather isolated. On a more interesting note, the
global models continue to show increased confidence in the potential
for a few mountain snow showers Wednesday evening and Thursday
morning. Both 850 mb and 925 temperatures are expected to be below 0
degrees C but the lack of moisture will be the huge question mark.
However, northwesterly upslope snow is always favorable, especially
near Jay Peak, to help squeeze out a few flurries. Accumulations
will be minor, if any, with afternoon temperatures on Thursday well
above freezing. Still, it`s a sign that seasons are changing. High
pressure will build back into the region Friday into Saturday with
warming temperatures expected as we head into next weekend.
&&
.AVIATION /03Z SUNDAY THROUGH THURSDAY/...
Through 00Z Monday...The primary forecast challenge continues to
be whether or not fog will be able to form in climatologically
favored ares given the day`s drier dew point temperatures.
Crossover temperatures are rather low, in the 30s and lower 40s,
across the North Country. However, light winds, and clear skies
will help with radiational cooling. Therefore, the previous TAFs
were largely maintained with the main change that onset of
mist/fog was delayed an hour at SLK/MPV by an hour given the
temperature trends. Best chances for IFR remains at SLK/MPV/EFK
between 07-12Z. Otherwise, calm or light drainage winds are
anticipated overnight before the pressure gradient tightens
after 15Z with southerly responding terminals like PBG/BTV see
some winds gusting around 20kts; elsewhere winds will be
lighter with gusts to around 15kts.
Outlook...
Sunday Night: Mainly VFR, with local IFR possible. Definite SHRA.
Monday: Mainly VFR, with areas MVFR possible. Chance SHRA.
Monday Night: VFR. Slight chance SHRA.
Tuesday: VFR. Slight chance SHRA.
Tuesday Night: VFR. Slight chance SHRA.
Wednesday: VFR. Chance SHRA.
Wednesday Night: Mainly VFR, with areas MVFR possible. Slight
chance SHRA.
Thursday: Mainly MVFR, with local IFR possible. Slight chance
SHRA.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Taber
NEAR TERM...Myskowski/Taber
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...Boyd/Taber
Area Forecast Discussion
National Weather Service Columbia SC
827 PM EDT Sat Oct 5 2024
.SYNOPSIS...
Surface high pressure is in control of the weather this weekend
with temperatures near or slightly above seasonable values. A
cold front moves through Monday night, ushering in a cooler and
drier air mass for the remainder of the work week. Meanwhile,
Tropical Storm Milton is expected to pass south and east of the
forecast area with breezy conditions possible late Wednesday
into Thursday.
&&
.NEAR TERM /UNTIL 7 AM SUNDAY MORNING/...
Key Messages:
- None
We have been watching a persistent shower over the last few
hours move from Richland County southwest through Lexington and
Saluda counties. This cell is finally showing signs of
dissipation now that the sun has set and should put an end to
the rain threat tonight. Outside of that lone shower, there are
scattered cumulus and stratocumulus across parts of the
northern Midlands but these should also wane during the next
hour or two. High clouds are expected to continue moving
northward into our forecast area tonight. Model guidance favors
the development of low clouds and/or patchy fog towards daybreak
but any mid to high level cloudiness will reduce the threat.
Its a warm and dry night otherwise with overnight lows in the
lower to mid 60s.
&&
.SHORT TERM /7 AM SUNDAY MORNING THROUGH SUNDAY NIGHT/...
Key Messages:
- Dry and warm weather expected.
High pressure aloft will be over the Southeast U.S. early next week.
An upper level trough passing through New England is expected to
swing a dry cold front through the region Sunday Night. The airmass
behind the front will be a little bit drier with dew points lowering
into the 50s, however temperatures will remain above normal with
highs in the 80s and lows in the upper 50s to mid 60s.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Key Messages:
- Continued dry weather with a noticeable cooling trend.
- A tropical system expected to move across Florida during the
middle of next week.
The Southeast U.S. should be between a deep upper level trough over
the New England and high pressure aloft over the Southwest U.S. A
Canadian surface high pressure system is anticipated to bring an
autumnal airmass into the region with slightly below normal high
temperatures and the coolest low temperatures since May.
Tropical Storm Milton has formed in the Gulf of Mexico. The NHC
forecast strengthens this system into a hurricane by mid-week
with a track across central Florida. At this time, the primary
concern for the Midlands and CSRA would be breezy to possibly
windy conditions late Wednesday through Thursday.
&&
.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
VFR conditions expected through much of the period but some
restrictions possible Sunday morning.
High pressure centered over western New York continues to ridge
southward into the Carolinas. However, low level moisture
remains abundant with dewpoints in the upper 60s and above
normal moisture at 925/850mb. Aloft, upper level ridging
persists with plenty of mid level dry air present above a
subsidence inversion as noted on the 23z HRRR analysis sounding.
This could provide favorable conditions for early morning
fog/stratus. Winds should be light and variable to calm
overnight before picking up from the northeast to east around 4
to 6 knots after 15z.
All MOS guidance as well as HRRR and NBM/HREF ensemble guidance
suggesting some stratus developing over the northern Midlands
and moving into the Columbia area after 10z with HREF MVFR cig
restriction probabilities over 70% for a few hours. Fog may be
more of a concern at prone OGB/AGS although some higher clouds
moving into the region from the southwest could limit that
threat. Decided to go ahead and include prevailing MVFR cigs at
CAE/CUB from 10z-15 with tempo IFR cigs and MVFR vsbys.
Elsewhere, confidence is lower so including restrictions at
AGS/DNL/OGB in a tempo group for fog 08z-12z and for cigs
12z-15z.
EXTENDED AVIATION OUTLOOK...No significant impacts to aviation
expected through mid-week, although brief early morning fog or
stratus will be possible.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.
&&
$$
Area Forecast Discussion
National Weather Service Quad Cities IA IL
620 PM CDT Sat Oct 5 2024
.KEY MESSAGES...
- Very warm and breezy conditions continue today will lead to
elevated fire danger across the area, particularly in cured
crop fields
- Cooler conditions on Sunday, with noticeably lower humidity
and breezy, very high fire danger for crop fields again.
- Dry conditions prevail throughout the long-term period
&&
.SHORT TERM /THROUGH SUNDAY/...
Issued at 112 PM CDT Sat Oct 5 2024
A cold front is expected to move through the area this evening.
This will bring the winds down overnight before ramping back up
tomorrow with the CAA behind the front. This evening, winds
will remain gusty as well, 15 to 25 MPH, as guidance continues
to show a mixed boundary layer. Winds will eventually shift to
the NW late. Clear skies tomorrow will promote deep mixing with
a cooler and drier air mass across the area. Temperatures will
be 15 to 20 degrees cooler tomorrow. Dewpoints are expected to
mix out as well, into the low to mid 30s. Decided to go lower
than the NBM here. The HRRR that usually does better with Td
mixing out seems to be overmixing as of late. So decided not to
go that low with Tds. This should drop RH tomorrow as well to
the mid 20 percent range. However, since GFDI is based mostly
on wind, temp and cured crops, we look to stay in very high GFDI
as opposed to Extreme category. Tomorrow will feel chilly
compared to today!
&&
.LONG TERM /SUNDAY NIGHT THROUGH SATURDAY/...
Issued at 206 PM CDT Sat Oct 5 2024
Rinse and repeat is the story of the long term. Start the period
with seasonal temperatures through midweek before upper level
ridging moves into the area. By the end of the week we are back
into the 80s. With dry conditions expect large diurnal swings in
temps again. Guidance today continues to show a consistent
message here. We look to remain dry through the period as well.
Sunday night into Monday, lows could be low enough that we could
see some frost across the far north. Will need to keep an eye on
this tomorrow. Will want to watch the Tds upstream to see how
far they drop in the next 24 hours.
&&
.AVIATION /00Z TAFS THROUGH 00Z SUNDAY/...
Issued at 606 PM CDT Sat Oct 5 2024
VFR conditions will prevail through the TAF period, with winds
being the main concern. Currently, we are seeing gusty southerly
winds, with gusts upwards to 25-30 KTs at times. A cold front
will pass through between 02-06z, with LLWS being an issue
during this timeframe throughout the area. The LLWS will be
about 40-50 KTs out of the southwest. After the cold front
passes, between 06-08z, winds will become much lighter and out
of the west-northwest. After 12z, we will see these winds pick
up quite a bit once again, with much of the area seeing
northwest gusts between 25-30 KTs through the day tomorrow.
&&
.FIRE WEATHER...
Issued at 1158 AM CDT Sat Oct 5 2024
Very high to low-end Extreme GFDI values for croplands are
forecast this afternoon, especially across east central Iowa.
Cured crops along with winds gusting to near 40 mph will drive
this threat. We are on the border for needing a red flag
warning, especially north and west of a Williamsburg Iowa to
Manchester Iowa line. Native grasses remain green, so they
should not be much of a factor. If a field fire were to start,
expect them to become difficult to control. A wind shift should
occur this evening and could change the direction of any fires
not out this evening. A short lull in wind tonight before we get
gusty again.
Tomorrow, winds behind the cold front aren`t as strong but
still enough to keep the entire area in very high GFDI for
croplands. Overall RHs will be lower, however with the crops
being cured, wind and temperature will drive the main GFDI
threats. Another SPS will likely be needed tomorrow.
&&
.CLIMATE...
Issued at 302 PM CDT Fri Oct 4 2024
Record High Temperatures October 5:
Burlington 89/2007
Cedar Rapids 89/1963 and previous years
Dubuque 87/1922
Moline 89/1922
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...None.
IL...None.
MO...None.
&&
$$
SHORT TERM...Gibbs
LONG TERM...Gibbs
AVIATION...Gunkel
FIRE WEATHER...Gibbs
CLIMATE...McClure
Area Forecast Discussion
National Weather Service Sioux Falls SD
1019 PM CDT Sat Oct 5 2024
.KEY MESSAGES...
- Critical fire danger continues across the entire area this
afternoon. A Red Flag Warning remains in effect until 8 PM this
evening.
- Little to no precipitation and above average high temperatures is
expected for next week. Weaker winds will allow for lower chances
for fire danger.
&&
.DISCUSSION...
Issued at 310 PM CDT Sat Oct 5 2024
Breezy to windy conditions continue across the area this afternoon.
Should see winds slowly wane through the rest of the afternoon hours
before a larger drop off occurs after sunset as the boundary layer
stabilizes. However, breezy winds will persist through the overnight
hours as the surface pressure gradient (SPG) remains tight across
the forecast area. Gusts up to about 25 mph are expected tonight.
The breezy winds will keep low temperatures a bit above average in
the mid to upper 40s.
Surface high pressure will be sliding into the area tomorrow. While
winds won`t be calm they will be much lighter then today. However,
gusts up to around 25 mph is possible, mainly east of I-29. These
winds will reside ahead of the surface high, where the tightest SPG
will lie. 850 mb temperatures will cool to the single digits. Mixing
this to the surface will result in a seasonable day with high
temperatures in the 60s across the area. However, dew points will be
in the 20s and 30s, contributing to low RH and potential fire
danger. More details are discussed in the fire weather section
below. The surface high will still reside over the forecast area
through the overnight hours, allowing low temperatures to fall to
the 30s to upper 40s. This may allow for some areas of frost to
develop. Confidence in this potential is low to moderate (30-40%
chance) though as drier air still resides across the area. If frost
were to develop, it would most likely develop in valley where lows
may drop a bit more.
Upper level ridging persists across the southwestern CONUS to begin
the work week. This will result in continued northwest flow aloft.
However warm air advection (WAA) will push 850 mb temperatures back
up to the teens aloft. This will result in a return to above average
temperatures with highs in the upper 60s and 70s. This could be
slightly mitigated though by wildfire smoke aloft. Latest HRRR
vertically integrated smoke shows smoke aloft beginning to enter the
forecast area early Monday morning. Still a bit too early to say how
thick the smoke will be but will continue to monitor this potential.
Low temperatures will fall to 40s overnight.
The same upper level ridging over the southwestern CONUS will
amplify for the middle and end of next week. This will allow for dry
conditions to persist across the Northern Plains. Ensembles also
support this as they all show a straight zero percent chance for a
hundredth of an inch of rain or more. However, ensembles also
support the potential for above average temperatures as they all
show a broad 50-90% chance for high temperatures to exceed 80
degrees F. All this to say that next week will be warm and dry. The
good news is that pressure gradients do not look to be that steep
given the ridging in place. This should result in lighter winds
across the region and reduce the potential for fire danger.
&&
.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1017 PM CDT Sat Oct 5 2024
Winds have largely diminished although occasional gusts
overnight in the 15-20 kt range remain possible. At the same
time, winds aloft remain strong enough for some occasional
LLWS. Northwesterly winds will again gusts in the 15-25 kt range
tomorrow with a decreasing trend from west to east through the
afternoon. VFR conditions will persist through the period.
&&
.FIRE WEATHER...
Issued at 310 PM CDT Sat Oct 5 2024
A cold front continues to push through the area this afternoon.
Southwesterly gusts ahead of the front will turn to out of the
northwest behind the boundary. Gusts between 30-45 mph are being
observed with the strongest gusts occurring across central South
Dakota. Dew points continue to fall behind the front, from the 50s
ahead of the boundary to the 30s behind it. With temperatures that
have warmed to the 70s and 80, relative humidity (RH) values are
falling behind the front with values down to teens to the low to mid
20s. The low RH and stronger winds have indeed resulted in critical
fire danger conditions across the area this afternoon. Winds will
drop off more abruptly as the boundary layer stabilizes after sunset
this evening. With a tighter surface pressure gradient (SPG)
residing across the area, winds will not go calm but remain breezy
through the overnight hours. Despite the breezy winds, RH will
increase, thus putting an end to the fire danger today.
Sunday presents another day of potential fire danger. This potential
is more uncertain though as surface high pressure will be sliding
through the forecast area. The tightest SPG will reside ahead of it
and thus will also be the same area where the strongest winds will
lie. Winds will be out of the northwest with gusts up to around 25
mph. With dew points remaining in the 20s and 30s, low RH values are
possible, down to about 20-25%, even though high temperatures will
only warm to the 60s. The lowest RH and strongest winds will reside
east of I-29. While this could result in critical fire danger
conditions in this area, there looks to be only minor overlap of the
strongest winds and lowest RH as the surface high will be relaxing
the SPG. Thus, the strongest winds will be weakening as RH drops to
or below 25% during the afternoon hours. Will closely monitor trends
for needing fire headlines tomorrow.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
DISCUSSION...Meyers
AVIATION...Kalin
FIRE WEATHER...Meyers
Area Forecast Discussion
National Weather Service Grand Rapids MI
1007 PM EDT Sat Oct 5 2024
.KEY MESSAGES...
- Chance of showers or a thunderstorm late tonight
- Breezy Sunday, increasing fire weather concerns
- Cool and dry next week, then warmer
&&
.UPDATE...
Issued at 1006 PM EDT Sat Oct 5 2024
Will lower overnight pops a bit especially south of Highway M-46
and will considering removing them entirely south of I-96. Strong
to severe convection currently in north central WI is firing in
area of stronger 700 mb theta-e advection, and all of this
activity is lifting northeast into Upper MI where the better
moisture/lift is present closer to the upper low/trough. However
there is narrow corridor of 700 mb RH greater than 70 percent
ahead of the incoming front which comes through our area overnight
and could touch off a few showers and storms mainly north of
M-46. HRRR runs have been consistent in keeping convection well to
our north and the 3KM NAM which had been the most ambitious CAM
for our area is backing off as well in the new 00Z run.
&&
.DISCUSSION...
Issued at 324 PM EDT Sat Oct 5 2024
- Chance of showers or a thunderstorm late tonight
The risk for an isolated severe wind gust for the US-10 area is
still conditional on there being thunderstorms developing this far
south. The overall thoughts on this setup haven`t changed much in
the past day. Most 12Z convection-allowing models are still shy of
developing robust convection near and south of US-10. The better
chances are in northern Michigan where better mid-level moisture
transport convergence and upper-level divergence will be.
However, given moderately steep lapse rates and somewhat higher
ambient relative humidity expected in the mid to upper levels, there
is a decent depth of potentially effective updraft parcels around
700 mb. Depending on the degree to which inhibition can be overcome,
the door is open for the possibility of high-based convection to
realize 500-1000 J/kg of CAPE concentrated in the hail growth layer.
Model forecast temperature profiles in surface-850 mb layer, while
too stable for potential updrafts, does not appear to be overly
stable to any hail-laden downdrafts that might occur. The low and
strong southwesterly low-level jet ahead of the cold front, with 45
to 50 knot winds just 1000 to 2000 feet above ground, would be
liable to be mixed down in isolated spots if stronger convective
pulses do occur. The main time for this threat will be between
midnight and 5 AM.
Even without showers or storms tonight, there may be a few hour
period of 40 mph gusts spilling to the surface, off the top of the
marine layer, within a few miles of Lake Michigan between Holland
and Ludington.
- Breezy Sunday, increasing fire weather concerns
After weeks of dry weather, the conditions Sunday afternoon will
approach Red Flag in a portion of central to southern Lower
Michigan, as humidity drops to around 30 percent and west winds
increase to 15 to 20 mph with gusts over 30 mph. Areas east of a
line from Mount Pleasant to Kalamazoo are most concerning for fire
weather conditions.
- Cool and dry next week, then warmer
We are in for another stretch of dry weather next week.
An upper trough Sunday into Monday over the Great Lakes will usher
in cooler air to the region. Highs in the lower to mid 60s will be
common Monday through Wednesday. However, a warming trend will
develop mid week and carry us into the weekend as high pressure at
the surface and a building ridge aloft bring in warmer air from the
south. Friday and Saturday will see highs in the lower to mid 70s.
Dry weather is expected through the period.
Frost is possible over the northern cwa Monday night through
Wednesday night as lows dip into the lower to mid 30s.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 742 PM EDT Sat Oct 5 2024
Forecast remains fairly consistent. A strong LLJ will create wind
shear for several hours tonight ahead of a cold front that will
move through after 06z. Shower activity is still expected along
the front with storms possible to the north. There remains some
uncertainty as to whether the precip will extend southward enough
to reach the terminals. Have continued the use of VCSH at GRR. The
wind shear will intensify between 06Z until it relents around 11Z.
Gusty winds will continue for much of Sunday with the chance for a
stratocu deck to move in late in the day Sunday, after 21Z.
Though, that low cloud deck should remain VFR.
&&
.MARINE...
Issued at 324 PM EDT Sat Oct 5 2024
Not much change to previous thinking. The small craft advisory has
started for gusty winds from the southeast today. Will become more
from the south, southwest, then west later tonight.
Previous discussion...
Strong southerly flow ramps up today into tonight and gradient flow
increases with the approach of a low pressure system. Offshore flow
dominates through much of the afternoon with gusts of 20-25 knots.
This evening, a 50 knot low level jet likely brings gusts of 35-40
knots north of Holland, even with marginal mixing conditons. A Gale
Warning has been issued from 00z-09z. South of Holland, Gusts around
30 knots are expected starting this afternoon resulting in the
issuance of a Small Craft Advisory. Isolated gusts to gales cannot
be ruled out South of Holland however short duration and low
confidence preclude the issuance of a gale warning. Scattered
showers and thunderstorms could also bring locally higher winds.
Small craft advisory conditions are likely to continue across the
entire nearshore waters after the Gale Warning expires through
Monday afternoon. The advisory south of Holland currently runs
through 21z Monday and an advisory will need to be issued upon the
expiration of the Gale Warning to cover the continuing gusty winds
north of Holland.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
MARINE...Small Craft Advisory until 5 PM EDT Monday for LMZ844-845.
Gale Warning until 5 AM EDT Sunday for LMZ846>849.
&&
$$
UPDATE...Meade
DISCUSSION...04/CAS
AVIATION...04/Ceru
MARINE...CAS/Thomas
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
900 PM CDT Sat Oct 5 2024
.KEY MESSAGES...
- Northwest winds gusting to 25 mph tomorrow afternoon will
combine with relative humidity of 20 to 25 percent to increase
risk for rapid fire spread.
- There is less than a 15% chance for any measurable
precipitation during the next 7 days, which will result in
developing or worsening drought conditions across central and
southeast IL.
&&
.UPDATE...
Issued at 900 PM CDT Sat Oct 5 2024
Skies will remain clear through the night and tomorrow. Winds will
be southerly tonight but then switch to west and then northwest
late tonight and through tomorrow. However, wind speed and gusts
were too high for current and expected conditions overnight. So,
made some changes there and lowered speeds. Did lower overnight
lows in northwest by a degree, but overall current forecast still
looked good. Update for the low temps and winds has been done with
updated text products forthcoming.
Auten
&&
.DISCUSSION...
Issued at 107 PM CDT Sat Oct 5 2024
An unseasonably warm Autumn day continues, with temps at 1pm
clocking in in the low to mid 80s. Southerly winds are gusting
around 20-25 mph; these will probably increase a little later this
afternoon into the evening when we should see a few 30+ mph gusts in
our northwest - nothing out of the ordinary for this time of year.
Dew points, which mixing has maintained in the upper 50s to around
60 so far today, should creep up a bit ahead of an approaching
cold front tonight when the HRRR brings them into the 61-64 degree
range in many locations along and east of the IL River. This will
be short-lived, however, with a dramatic plunge behind the cold
front which should reach the IL River around 2am and clear the CWA
by noon tomorrow.
Behind that front tomorrow afternoon, CAA will enhance mixing to
yield both northwest wind gusts around 20-25+ mph (highest north)
and dewpoints in the low 30s (which will result in RH values dipping
to around 20% for several hours). The 12z HREF suggests the joint
probability (i.e., a chance of multiple criteria being met
simultaneously) of wind gusts > 25 mph and RH < 25% is around 10-
30%, but personally I think this is a bit low because of the
NAMNest`s high bias in boundary layer moisture. Time will tell, but
in any case: (1) we shouldn`t need a Red Flag Warning (RFW) because
our 10 h fuel moisture is hovering near 15% (RFW criteria is 8%),
and (2) nonetheless it will be breezy and relatively dry implying
conditions are favorable for rapid fire spread. Farmers should use
caution when harvesting, and anyone burning should exercise caution.
Do not carelessly discard cigarettes or matches.
Conditions turn cooler by Monday when most locations are expected to
struggle to reach 70 degF. If winds end up on the lighter side of
guidance, the drier airmass and lack of clouds should result in
temps dipping well into the 40s tomorrow morning and low 40s to
locally upper 30s Tuesday morning; in fact, NBM suggests
probabilities as high as 30-40% for min temps less than 40 degF in
the lower-elevation, cold-prone locations Tuesday morning.
The LREF mean suggests 500mb heights will gradually rise as an upper
ridge slowly expands into the Midwest mid to late week, implying a
subtle warming trend and absence of appreciable precip chances into
the upcoming weekend. NBM suggests chances for highs over 80 degF
climb to more than 40% near and west of I-55 both Friday and
Saturday - suggesting a return to unseasonable warmth once again.
Bumgardner
&&
.AVIATION... (For the 00z TAFs through 00z Sunday Evening)
Issued at 635 PM CDT Sat Oct 5 2024
VFR conditions will prevail at all TAF sites next 24hrs, with
clear skies through the period. Winds will be out of the south
this evening with wind speeds around 12-15kts. Then as a dry sfc
front slides across the area, winds will become westerly with
speeds less than 10kts. Daytime tomorrow, winds will become
northwesterly and become gusty, with speeds of 22-25kts.
Auten
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service North Platte NE
624 PM CDT Sat Oct 5 2024
.KEY MESSAGES...
- Dry weather continues for the next 7 days.
- A gradual warning trend will occur Sunday through Friday
followed by a strong Pacific cold front and cooler weather
Saturday.
- Very dry air remain across western and north central Nebraska
until the cold front arrives next Saturday. Humidity will fall
to 15 to 20 percent and elevated fire weather conditions will
continue across the region.
&&
.SHORT TERM /THROUGH SUNDAY NIGHT/...
Issued at 314 PM CDT Sat Oct 5 2024
1025mb Pacific high pressure should be centered across the Sandhills
and swrn Nebraska by 12z Sunday morning. The guidance blend
continues to advertise lows in the upper 20s to lower 30s in this
area. Bias correction raises lows a couple of degrees and this is
the official forecast.
The guidance blend and the short term model blend were close
predicting highs in the upper 60s and 70s Sunday. Modest cold air
advection across ncntl Nebraska Sunday holds highs in the upper 60s
to around 70 while modest warm advection across wrn Nebraska allows
for highs in the mid 70s.
South winds and return flow around sfc high pressure centered across
ern Nebraska Sunday night should maintain warm air advection across
wrn/ncntl Nebraska but the models are very modest with this feature.
The cooler guidance blend was selected for this reason and lows in
the 30s to lower 40s are in place.
&&
.LONG TERM /MONDAY THROUGH SATURDAY/...
Issued at 314 PM CDT Sat Oct 5 2024
There is little change in the extended forecast philosophy today.
The strong storm across Manitoba this afternoon will continue
moving east and form a closed upper level low across James Bay
Monday. The upper low will move slowly east through the Canadian
Maritime region next week and upstream ridging will develop
across the cntl Plains. By Thursday, a long wave trof will
approach the Pacific Northwest and both the ridging and approach
of the trof will support warm air advection across Nebraska
Monday through Friday. H850 temperatures will warm into the
lower to mid 20s centigrade by Friday. Highs in the 80s are in
place Tuesday and Wednesday with a few readings around 90
Thursday and Friday.
A strong Pacific cold front should move into Nebraska next Saturday
spreading cooler air into the region. The ECM is a bit slower with
the timing of the front; the GFS is faster, but the concept is the
same. The extended forecast continues dry with little if any chance
of rain.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 623 PM CDT Sat Oct 5 2024
VFR conditions will prevail across western and north central
Nebraska through tomorrow evening. The gusty winds behind the cold
front are in the process of diminishing, and should be calmed this
evening and overnight. Generally light winds are expected today and
tomorrow, with a possible wind shift late tomorrow afternoon into
the evening, near the end of the effective TAF period. Timing of the
shift will most likely be caught in the following TAFs. Otherwise,
skies may be smoky from wildfires across Wyoming and the western
United States, however, no impacts to visibility are expected at
this time.
&&
.FIRE WEATHER...
Issued at 315 PM CDT Sat Oct 5 2024
Areas of smoke are in the forecast tonight through Sunday
night. Visible satellite and the morning runs of the vertically
integrated and near sfc smoke products from the RAP and HRRR
models show smoke from fires across WY and the wrn U.S. damming
up against the cntl high Plains tonight. The reason for this is
Pacific high pressure building through Nebraska tonight will
trap the smoke to the west. The high pressure will move slowly
east toward Iowa Sunday and Sunday night. The smoke will follow
the track of the high pressure system according to the models.
No strong weather systems which would present an obvious signal for
critical fire weather conditions are indicated Sunday through next
Saturday. Monday and Friday will be days to watch. Southwest winds
may gust to 25 mph or stronger across ncntl Nebraska Monday and
across much of western and north central Nebraska Friday. A strong
cold front will sweep through the region Saturday cooling
temperatures and increasing humidity.
Very dry air remain across western and north central Nebraska until
the cold front arrives next Saturday. Humidity will fall to 15 to 20
percent and elevated fire weather conditions will continue across
the region until Saturday.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 9 PM CDT /8 PM MDT/ this evening for
NEZ204-206-208>210-219.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Richie
FIRE WEATHER...CDC
Area Forecast Discussion
National Weather Service Marquette MI
623 PM EDT Sat Oct 5 2024
.KEY MESSAGES...
- Critical fire wx conditions end west to east through early
evening. Relative humidity increases, but gusty south winds to
30-40mph continue into early evening.
- Band of showers and some thunderstorms, lasting only 30-60
minutes, rapidly moves across the area tonight. Five percent
chance of strong winds and small hail with strongest storms.
- A Wind Advisory is in effect for the Keweenaw Peninsula on
Sunday with strong westerlies behind the front gusting above
45 mph.
- Cold air aloft will force light lake effect rain showers on
Sunday across the northwesterly lake effect bands and over the
east half occasionally (15-35%) on Monday and Tuesday.
- Dry weather is expected in the back half of the work week, but
fire weather concerns are limited by light winds.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 314 PM EDT Sat Oct 5 2024
Water vapor imagery and RAP analysis show a vigorous, well-defined
shortwave over southern Manitoba. At the sfc, associated 987mb low
pres is nearing Lake Winnipeg. Cold front extends sse from the low,
bisecting MN. Ahead of the front, tightening pres gradient and
mostly sunny skies to build mixed layer have resulted in gusty s
winds up to 30-40mph this aftn. The drier models had a pretty good
handle on the mixing to lower dwpts today, particularly across nw
Upper MI thru central Upper MI and then eastward across northern
portions of eastern Upper MI. With RHs in the upper 20s to mid 30s
percent range, the gusty winds and ongoing drought conditions are
leading to critical wildfire conditions this aftn.
Dwpts are already rising thru the 40s and into the 50s F in WI in
the flow ahead of the approaching cold front. These higher dwpts are
beginning to spread across the MI-WI stateline over western Upper
MI, and during the next several hrs, dwpts will continue to increase
from the sw, resulting in RH increasing from sw to ne across the
area. RH may hang down toward 30pct e of Munising thru about 6 PM.
Winds will probably tick up a bit more in the next few hrs. Have
some concerns that downslope locations around Copper Harbor and in n
central Upper MI near Lake Superior, especially Marquette to
Munising, may have 2-3hrs of wind advy level gusts above 45mph. Will
continue to monitor.
Tonight, attention turns to cold front which will surge e across the
area. While shra have not developed along the front yet, looks like
a narrow band of sct to bkn shra/tsra will accompany the front as
increasing forcing works on the ongoing prefrontal increase in
moisture. For most, pcpn will last no more than 30-60 minutes.
Narrow band and quick movement will limit pcpn amounts, maybe 0.3 to
0.4 inches at most where heaviest shra occur. With the strong wind
fields, strong sfc wind gusts may occur, particularly with cells
that produce heavier rainfall. Some hail not out of the question.
Skies will quickly clear with fropa and passage of the shra. Late
tonight, increasingly colder air flowing into the area on westerly
winds (850mb temps down to around 0C across western Lake Superior by
12z) along with increasing low-level moisture wrapping around sfc
low pres in northern Ontario will result in stratocu
spreading/developing into western Upper MI. A few shra may develop
off of the lake into nw Upper MI prior to 12z.
&&
.LONG TERM /SUNDAY THROUGH SATURDAY/...
Issued at 429 PM EDT Sat Oct 5 2024
Windy conditions are expected on Sunday in the wake of tonight`s
cold front. A second cold front positioned over central Upper MI
Sunday morning will drape southwest into WI, continuing east through
the day as the mid level trough tracks east through northern Ontario
sending the sfc low toward Hudson Bay. A stronger pressure gradient
and efficient mixing up to ~5kft where 35-40kt winds are present
during the day will result in widespread west becoming northwest
gusts between 25-35mph. Higher gusts are expected in the Keweenaw
Peninsula ~40-50mph. Given that the latest ECMWF probabilities of
gusts exceeding 34kts is +90% in the entire Keweenaw Peninsula, the
Wind Advisory will continue as is for Sunday (6AM - 8PM EDT Sun).
Note: While the strongest and most persistent winds are expected in
the Keweenaw, model soundings do leave potential for more isolated
gusts up into the 40mph range across much of the UP during the day,
especially near Lake Superior. Otherwise highs peak late
morning/early afternoon in the 50s, warmer in the east and south-
central. Meanwhile, CAA from northwest flow brings 850mb temps drop
to near 0C. Although Lake Superior has begun to drop closer to
normal, it still remains fairly warm around 15C which will be
supportive delta-Ts for lake effect showers. Coverage will be best
over the east where the cyclonic flow is maximized. Also, given the
strong gales across Lake Superior, waves building up to 7-12ft may
cause some minor lakeshore erosion along the western shores between
Ontonagon and Keweenaw Counties as well as in the east along Alger
and Luce County beaches.
Drier air begins to work its way in from the northwest Sunday night
as high pressure builds in over the Mississippi Valley. This begins
to diminish showers from west to east. Light accumulations from
Sunday into Sunday night should remain below 0.25". Skies clear out
from west to east as a result of the drier air, allowing for temps to
drop into the 30s to low 40s, warmer by the lakeshores and in the
east where cloud cover lingers on longer. Expect areas of frost
Sunday night, particularly in the interior west and south-central.
While winds begin to taper down Sunday night, gusts into the 20mph
range may persist into Monday in the Keweenaw and in the east.
Although Sunday night/Monday morning would be the last frost-freeze
headlines, near freezing temps are likely away from the lakeshores
in the early portions of this week.
Light lake effect rain chances will periodically grace the eastern
UP Monday and Tuesday as the troughing aloft stalls over Quebec and
minor shortwaves pivot around and through the east. However,
soundings leave much to desire for available moisture with only
shallow saturation near the top of the inversion. Also, as strong
winds continue to mix up the lake over the next few days, sfc temps
will drop lowering delta-Ts. Thus, certainty in coverage and
intensity of any shortwave-boosted lake effect diminishes with time.
Scattered cloud cover over the east with little to no accumulation
is the most likely solution.
Mid level ridging builds east from the Plains to the Great Lakes
late next week into the weekend, keeping sfc high pressure over the
Great Lakes for much of that time. This means another stretch of
mostly dry weather is expected with temps well above normal. Despite
this period of drier conditions, winds remain light under this high
pressure somewhat limiting fire weather concerns. Will need to
monitor this for any changes as a good portion of the eastern UP is
in a Severe Drought.
&&
.AVIATION /00Z TAFS THROUGH 00Z MONDAY/...
Issued at 623 PM EDT Sat Oct 5 2024
A cold front will move quickly across the area tonight, accompanied
by a narrow band of shra and a few tsra in the 01-05z time frame.
Pcpn will only last 45 minutes to perhaps up to 90 minutes at each
terminal. Brief MVFR will be possible, mainly at SAW and CMX. Skies
will quickly clear with fropa. Increasingly colder air and low-level
moisture arriving early Sun will then lead to MVFR cigs developing
at all terminals. Some lake enhanced -shra will also develop,
especially at CMX. W to wnw winds on Sun will gust to 30-35kt at
IWD/SAW and to 40-45kt at CMX.
&&
.MARINE...
Issued at 458 PM EDT Sat Oct 5 2024
South-southeast gales this afternoon over the eastern two thirds of
Lake Superior continue into this evening ahead of a cold front,
strongest winds are expected north of the Keweenaw with high end
gale force gusts to 45 kts possible. As a low pressure system tracks
through northern Ontario, a cold front progresses across the lake
tonight. Gales to 40 kts will remain most likely along the US/Canada
maritime border ahead of the eastward sweeping cold front. Winds
quickly veer southwest behind the front, then west late tonight as
they begin to quickly increase again. High end gales to 40-45 kts
are expected Sunday morning over the west half with gales up to 40
kts over the east. Winds fall below gales from west to east Sunday
night and linger around 25 kts through Monday evening. High pressure
over the Great Lakes will keep wind gusts mainly below 20 kt for the
remainder of the week. Some elevated thunderstorms will be along the
cold front tonight, with some being capable of producing strong
winds and small hail. Wave heights with the southerlies ahead of the
cold front will peak east of Isle Royale at up to 15 feet, with the
westerlies behind the front forcing a broad swath of 10-15 ft waves
from the Western Lake Superior Buoy to Whitefish Point. Waves fall
below 4 feet across the lake by Tuesday morning.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
Wind Advisory until 7 PM EDT this evening for MIZ001-005-006.
Wind Advisory from 6 AM to 8 PM EDT Sunday for MIZ001-003.
Red Flag Warning until 8 PM EDT this evening for MIZ006-007-
014-085>088-095>097.
Lake Superior...
Gale Warning from 2 AM EDT /1 AM CDT/ to 8 PM EDT /7 PM CDT/
Sunday for LSZ162-240-241.
Gale Warning until midnight EDT Sunday night for LSZ242-263.
Gale Warning until 2 AM EDT Monday for LSZ243>251-264>267.
Lake Michigan...
Gale Warning until 2 AM EDT Sunday for LMZ221-248-250.
&&
$$
SHORT TERM...Rolfson
LONG TERM...Jablonski
AVIATION...07
MARINE...Jablonski
Area Forecast Discussion
National Weather Service Pocatello ID
148 PM MDT Sat Oct 5 2024
.SHORT TERM...Tonight through Sunday night.
Clear skies expected the remainder of the weekend with significant
warming on Sunday. Lows tonight will be in the 20s and 30s
mountains and 30s and 40s in the valleys. Some areas in the Arco
Desert will reach 34 degrees but not expecting widespread frost or
freeze to occur. Highs on Sunday will be in the 60s to lower 70s
mountains and 70s to lower 80s valleys. Lows Sunday night in the
30s mountains and upper 30s to mid 40s valleys. Winds will
continue to die down tonight and not expecting significant winds
on Sunday.
GK
.LONG TERM...Monday through Saturday.
Monday will continue the dry and very mild conditions with highs
in the mountains well into the 60s and 70s with 70s and 80s
valleys once again. There is a very weak system Tuesday and model
blends have added a slight chance of showers in the southeast
corner of Idaho mainly the Bear Lake region and southeast
Highlands. Low confidence in rain actually falling. It will be dry
and warm Wednesday and Thursday with high temperatures remaining
10 to 15 degrees above normal with highs in the 70s and 80s for
the most part. The models indicate an upper level trof bringing at
least a slight chance for showers Friday and Saturday mainly in
the mountains but high uncertainty as GFS shows more precipitation
and a low closing off. Temperatures do cool off with highs 60s and
70s Friday and 50s and 60s Saturday with the trof expected to
produce some substantial cooling. Not expecting significant wind
impacts in the long term period.
GK
&&
.AVIATION...Expect VFR conditions with clear skies through the
period as high pressure builds into the area. Winds will be elevated
early this afternoon before dropping off by late this afternoon into
early evening and remaining overall light through tomorrow.
Wyatt
&&
.FIRE WEATHER...High pressure is building in across the area today
behind an exiting cold front. Look for lingering 20 to 30 mph gusts
across the Snake plain and southward through mid afternoon. Then
winds drop off, especially by the evening. Today, expect a 10 to 15
degree F drop in daytime high temperatures from Friday`s record heat
(in Challis, Pocatello, Idaho Falls, and Rexburg), and expect an
overall rise in humidity staying above critical thresholds for most
areas. The one exception is lower elevations in the Central Idaho
mountains where critical relative humidity is expected this
afternoon. Temperatures will start warming again for Sunday and
Monday. Models are still showing a weak trough on Tuesday. With this
trough models are still showing a 20 to 30 percent chance of
precipiation over the Bear Lake area, zone 413. But for everyone
else, expect continued well above normal temperatures and solid
below normal precipitation for this next week. Models are still
trying to bring a weak system through the area next weekend. Though
any precipitation still looks to be very light next weekend.
However, temperatures for next weekend are forecast to drop down to
near normal to slightly below normal, and relative humidity for next
weekend looks to rise significantly as well.
Wyatt
&&
.AIR QUALITY...Air quality has dropped to moderate for a few
of our northern areas from smoke from fires across mainly our
northern areas and fires in western Idaho. THe HRRR smoke model
shows more smoke moving into our area late this afternoon through
the evening with fires in western Idaho becoming more active again.
Check airnow.gov for current air quality and air quality forecasts.
Wyatt
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion
National Weather Service Phoenix AZ
421 PM MST Sat Oct 5 2024
.UPDATE...Updated 00z Aviation Discussion...
&&
.SYNOPSIS...
Record-breaking heat will continue through at least Monday, with
very little day-to-day changes in the weather pattern. An Excessive
Heat Warning remains in effect through Monday as afternoon high
temperatures reach upwards of 15 degrees above normal. A slight
downtrend in temperatures is expected by the middle to end of next
week as a weak disturbance moves in from the west, but temperatures
will continue to remain above normal.
&&
.DISCUSSION...
A hot, dry weekend is underway as a strong ridge of high pressure
over the southwest CONUS continues to promote record-breaking
excessive heat. As of noon, Phoenix Sky Harbor has reached 106
degrees, which breaks the daily record high and now brings Phoenix
up to 12 consecutive days of temperatures tying or breaking daily
record highs. In addition to the record highs, Phoenix has now had
8 consecutive days of record warm lows. Record-breaking
temperatures will continue through at least Monday as temperatures
climb upwards of ~15 degrees above normal. Anyone with weekend
plans should take the necessary heat safety measures to protect
against the heat.
The ridge of high pressure over the Desert Southwest has
strengthened with RAP analysis showing 500 mb heights upwards of 592-
593 dm over the region. As a result, temperatures for many lower
desert locales will top out around 110 degrees through Monday, which
will shatter daily record highs across our area. Temperatures of
this magnitude for this time of year will continue to promote
widespread Major to areas of Extreme HeatRisk and thus an Excessive
Heat Warning remains in effect for much of the lower deserts through
Monday evening. For some context in regards to just how abnormal it
is to see temperatures of this magnitude in October, the record
latest 110 degree temperature occurrence in Phoenix prior to this
year was September 19, 2010, while the average (1991-2020) last 110
degree temperature occurrence is August 26th. Meanwhile, the average
last 100 degree temperature occurrence is today, October 5th.
Temperatures early next week will gradually trend downward, though
the NBM keeps temperatures hot enough into Tuesday to support some
continued areas of Major HeatRisk. Thus, the Excessive Heat Warning
could be extended through Tuesday for parts of the area in future
forecast updates.
A weak shortwave trough will approach the southern coast of
California going into the middle part of next week, leading to
gradual weak height falls over the region. Additionally, the weak
disturbance will also import some mid and upper level moisture,
which could be enough to promote shower development across parts of
the Arizona high terrain but otherwise will lead to an increase in
cloud cover over the region. Temperatures will respond to the weak
shortwave by gradually trending downward during the mid to latter
part of next week, though still remaining well above seasonal
normals as forecast highs remain in the 100-105 degrees for most
lower desert areas. Uncertainty increases heading into next weekend
as guidance suggest a deeper eastern Pacific trough will propagate
into the western CONUS. At this point in the forecast, it`s no
surprise to see a lot of uncertainty showing up in the global
ensemble clusters in regards to the evolution of this trough.
Something to watch as a deeper trough solution into the western
CONUS could finally push temperatures down below 100 degrees for
our area.
&&
.AVIATION...Updated at 2315Z.
South Central Arizona including KPHX, KIWA, KSDL, and KDVT; and
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns under mostly clear skies can be
expected through the TAF period. Overall wind pattern will
continue to exhibit the typical diurnal tendencies with light
speeds under 7 kts. There will likely be extended periods of very
light/calm and variable winds, especially during the periods of
diurnal transition.
&&
.FIRE WEATHER...
Dry and abnormally hot conditions will persist through early next
week, with lower desert highs ranging between 104-112 each
afternoon. There will be little to no day-to-day change in the
weather through Monday with the continued heat, mostly clear skies,
and light winds. MinRH values will range between 5-15% each
afternoon, while MaxRH readings are expected to be between 20-35%,
with locally higher values in Yuma and Imperial Counties. There will
be a very slight increase in moisture beginning around Tuesday that
may keep MinRH values from falling into the single digits, but most
areas will still see 10-15% readings in the afternoon through the
end of next week. There will also be potential for some regional
rain showers with the moisture increase, but at this time the
chances are very low (5% or less) across the lower deserts and CWR
is near zero. Winds will follow familiar diurnal trends, with
occasional afternoon gusts near 15-25 mph.
&&
.CLIMATE...
Record highs through next Wednesday:
Date Phoenix Yuma El Centro
---- ------- ---- ---------
Oct 5 105 in 2020 108 in 1917 106 in 2020
Oct 6 105 in 1917 108 in 1980 106 in 1964
Oct 7 104 in 1991 108 in 1987 105 in 1991
Oct 8 104 in 1987 107 in 1996 106 in 1996
Oct 9 103 in 1996 106 in 1996 104 in 1996
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Monday for AZZ530>544-546-
548>551-553>555-559.
CA...Excessive Heat Warning until 8 PM PDT Monday for CAZ562-566-567-
569-570.
&&
$$
DISCUSSION...Smith
AVIATION...Lojero
FIRE WEATHER...Benedict/RW
CLIMATE...18