Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/08/23
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
614 PM CDT Thu Sep 7 2023
.UPDATE...
Issued at 609 PM CDT Thu Sep 7 2023
Made some minor adjustments to hourly pops this evening.
Also added in some patcy smoke across the Missouri River valley
since observations indicate visibilities around 4 to 5 miles in
some lingering near surface smoke. The HRRR smoke indicates this
may last through early Friday morning.
&&
.SHORT TERM...(This Evening through Friday Night)
Issued at 306 PM CDT Thu Sep 7 2023
The main forecast challenge in the near term revolves around
precipitation chances this evening across the south, then again
across the much of the area Friday night. An upper level shortwave
currently over southwestern South Dakota will slide southeastward
late this afternoon and early this evening, just clipping the far
southwestern CWA. Weak ridging builds over the area late tonight and
Friday before another, albeit weaker, shortwave tracks across the
area Friday night.
At the surface, ongoing shower and thunderstorm activity over parts
of the southern CWA will exit the area later this afternoon.
Additional precipitation is expected to develop with the first
aforementioned shortwave, but most of the CAMS indicate it will stay
south of the CWA. Weak low pressure will remain over the area
tonight and Friday, but do not expect to see any precipitation
associated with it until the second aforementioned shortwave reaches
the area Friday night. Best timing looks to be after midnight, with
all but the far eastern CWA seeing a decent chance of some rain
before sunrise Saturday morning. Instability will be fairly weak
during this time, but will see some shear values in excess of 40
knots at times, so cannot rule out some convective activity.
Low temperatures tonight will be in the lower to mid 50s. High
temperatures on Friday will be in the 80s. Lows Friday night will be
in the mid to upper 50s.
.LONG TERM...(Saturday through Thursday)
Issued at 306 PM CDT Thu Sep 7 2023
When the period opens Saturday morning, a precipitation event is
expected to be ongoing. The system`s forcing/lift and associated
precipitation should be departing the CWA by Saturday evening. Then,
for the time being, the majority of the rest of the extended appears
dry, although NBM`s PoPs may eventually begin to smear some WAA-
forcing low-end slt chance values across portions of the CWA toward
the end of the period (Thursday/Thursday night) with the advent of
the next upper low moving east-southeast through the central/south-
central region of Canada.
There are two things happening in the extended, regarding upper
steering flow. The first thing is, when the period opens, there is
split flow happening over the western CONUS with a high-amplitude
upper ridge extending up into western Canada and more zonal flow
undercutting it further down across the mid-section of the U.S. It
is for this reason (split flow) that there is generally low to
moderate forecast confidence in how things will play out in the out
periods.
Meanwhile, the eastern half of NOAM is influenced by longwave
troughiness in one form or another. By the end of the period, this
western NOAM upper ridge is being redirected/shunted south and east
across the region, while the eastern NOAM upper trof reinforces
itself, and eventually a whole new upper ridge emerges over the U.S.
west coast. This amounts to mainly weak upper flow or northwest flow
over the CWA.
During this time cooler air will be advected into the CWA Saturday
into Sunday. But, without a really good pattern in which to warm air
advect in the low levels, this coolish airmass will warm mainly
through airmass moderation from daytime insulation over time. Right
at the end of the period, when the next upper low out over Canada
moves east to reinforce the eastern NOAM upper level longwave
troffing, this CWA will get into a period of low to mid-level
WAA/forcing and potentially some WAA rain showers. Until then,
expect temperatures to be running seasonably warm to, perhaps, a few
degrees below climo normal for mid-September.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 609 PM CDT Thu Sep 7 2023
Terminals KABR,KATY,KPIR,KMBG
VFR conditions will prevail across the east. Near surface smoke is
expected to cause MVFR vsby near KMBG and KPIR tonight with
improvement sometime Friday morning.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...Wise
SHORT TERM...Parkin
LONG TERM...Dorn
AVIATION...Wise
AREA FORECAST DISCUSSION
National Weather Service Wakefield VA
956 PM EDT Thu Sep 7 2023
.SYNOPSIS...
A weak trough of low pressure is in place across the region this
evening, with a cold front approaching the Appalachians from
the west. The front will continue approaching from the west on
Friday, and will become nearly stationary across the region over
the weekend, bringing a chance for showers and thunderstorms,
with temperatures cooling down to near normal.
&&
.NEAR TERM /UNTIL 8 AM FRIDAY MORNING/...
As of 910 PM EDT Thursday...
Latest sfc analysis reveals an upper level trough axis from
Ontario S to the eastern Gulf coast, with a portion of this
trough starting to become cutoff from the TN Valley into
AL/GA/northern FL. A weakening cold front is located along the
western slope of the Appalachians, and with ample instability
earlier today out ahead of the front, along with steep low and
mid level lapse rates, the storms across the piedmont and into
metro RIC brought some strong/locally damaging winds, hail, and
locally heavy rain. THis was in spite of rather weak deep layer
shear of only ~20kt. With the loss of daytime heating, the
storms have weakened considerably, though some gusty winds and
brief heavy downpours will persist for a few more hrs.
Temperatures have dropped ~30F since this aftn in portions of
central VA that had the heavy rain (from upper 90s/around 100F
to the upper 60s/lower 70s), while areas that have remained
rain-free across SE VA and NE NC still in the 80s. Diminishing
PoPs overnight, with patchy fog possible in the piedmont,
especially where it rained. Lows range from the mid to upper 60s
across the piedmont, to the low-mid 70s across the eastern
shore, as well as SE VA and NE NC.
&&
.SHORT TERM /8 AM FRIDAY MORNING THROUGH SUNDAY/...
As of 310 PM EDT Thursday...
The upper trough remains centered just to our west on Friday
with the trough axis potentially moving a bit farther to the
east. The surface cold front struggles to push eastward as it
becomes nearly parallel to the flow aloft (and likely remains to
our west through the end of the week). Still some uncertainty
regarding coverage of convection tomorrow. Some CAMs, like the
HRRR keep the area dry until late in the afternoon, then bring
decent coverage for NW portions, while others initiate
convection in south-central/south eastern portions of the area
earlier in the afternoon before bringing a line of storms
through. The best chc of storms is west of a Tappahannock-
Wakefield-Ahoskie line. The highest tstm chances are during the
aftn/evening before the convection gradually weakens overnight.
PoPs are ~40-50% across far NW portions of the FA, 30-50% along
the I-95 corridor, and only 20-30% near the coast. There is a
low but non-zero threat for locally damaging wind gusts on Fri
with the strongest storms. SPC again has the NW half of the area
in a MRGL risk. The upper trough lingers just to our west on
Saturday with scattered showers/tstms once again expected (with
the highest coverage during the aftn/evening). The highest PoPs
are once again west of I-95, but even coastal zones will have a
better chc of precipitation on Sat than Fri as upper heights
finally start falling a bit by late in the day. Highs on Fri
will be in the low 90s, then mid to upper 80s Sat. Locally heavy
rain is possible (mainly along/west of I-95) on both Fri and
Sat, but this should not cause any major issues given the dry
antecedent conditions.
Still looking unsettled Sunday as the upper trough finally pushes
into the local area and the sfc front stalls. Precip chances
increase through the day. Highest PoPs are once again in NW counties
at ~60%, 40-55% elsewhere. Highs will be in the upper 70s for far
western counties and low-mid 80s elsewhere.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
As of 310 PM EDT Thursday...
During the early week period, the trough will broaden, keeping the
flow south-westerly. With the front stalling over the area, there
will still be a chance for afternoon/evening thunderstorms on Mon
and Tues. It does look drier than the weekend, though, as the front
washes out. Precip chances increase again mid-week as a stronger low
pressure aloft dives out of central Canada into the Great lakes with
a stronger front approaching at the surface. Highs will range from
the low 80s well inland to the mid-upper 80s near the coast
Mon/Tues, then a few degrees cooler on Wednesday.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
As of 800 PM EDT Thursday...
VFR conditions have returned to all main terminals (RIC had
strong winds and brief heavy rain in tstms at the start of the
TAF period). Still seeing a few tstms mainly across east central
VA, and into the mid/upper Ches Bay, so there is a low chc that
SBY could briefly see showers through ~04Z, but have left this
out of the TAF for now. Otherwise, mainly VFR overnight, with
patchy fog possible W of I-95, unlikely to affect any of the
main terminals. VFR w/ southerly winds around 10kt on Fri.
Scattered late day tstms are expected, but w/ too low of a
coverage to include mention in any of the TAFs.
Outlook: Evening tstm chances increase Friday (especially at
RIC) ahead of an approaching cold front. The front likely
lingers over the area into this weekend, with variable clouds
and at least scattered showers and storms possible at all
terminals both Saturday and Sunday (primarily in the
aftn/evening). Generally drier w/ only a slight chc for
showers/storms Monday/Tuesday.
&&
.MARINE...
As of 320 PM EDT Thursday...
Main message on the marine side is conditions overall remain sub-SCA
through the early-middle part of next week before long-period swell
from Hurricane Lee begins affecting the local waters.
South winds 5-15 kt will continue into tonight, except for
local seabreeze influences through the evening. There`s the
possibility of some gusts up to 20 kt for a couple of hours
through 10 pm for the Bay but not worthy of an SCA at this time.
Cold front gradually approaches the area through Sat before
stalling inland over the weekend. S-SSE winds of 10-15 kt are
expected Fri-Sun. Seas remain 2-3 ft and waves 1-2 ft through
most of the forecast period.
Looking into the extended period, global model guidance agrees that
Hurricane Lee will slowly be moving NW out of the ern Caribbean into
next week. Long-period swell will likely reach the area waters by
the middle of next week w/ elevated seas possible.
&&
.CLIMATE...
New daily record set at SBY again today (Thu), and a tie at ECG
with other terminals again falling short. Highs in the 90s are
expected on Friday, but additional record highs are currently
not forecast. Since it might be close, have added Fri record
highs to the list below. This heatwave will end after Friday,
and its is `possible` that there will not be any additional
90-degree+ temperatures for the rest of the year.
* The last time RIC had 2 consecutive days with a high of 100+
was July 7-8th, 2012 (the last time in September was 3
consecutive 5th/6th/7th in 1954).
For reference, Septembers with the most days reaching 90/95/100
degrees are also listed.
*also in earlier years
** denoted new daily record high temperature
* Date: Wed 9/6 (Actual) Thu 9/7 (Actual) Fri 9/8
* RIC: 102/1954 (101) 103/1954 (100) 97 (1954)
* ORF: 98/1899 (93) 98/1954 (96) 96 (1985)
* SBY: 95/1983 (**97) 95/1943 (**97) 96 (1939)
* ECG: 98/1954 (96) 95/1985 (**95) 98 (1985)
Most 90F+/95+/100+ Days in September:
90F+ Days 95+ Days 100+ Days
* RIC: 15 in 1970 9 in 1930 3 in 1954
* ORF: 10 in *1930 6 in 1985 2 in 1895
* SBY: 16 in 1930 4 in 1930 1 in 1932
* ECG: 10 in *2018 7 in 1985 (none)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...ERI
NEAR TERM...AM/LKB
SHORT TERM...AM/ERI
LONG TERM...AM
AVIATION...AM/LKB
MARINE...JDM/SW
CLIMATE...
Area Forecast Discussion
National Weather Service Cheyenne WY
1006 PM MDT Thu Sep 7 2023
.SHORT TERM...(This evening through Friday)
Issued at 253 PM MDT Thu Sep 7 2023
Continuing to see gusty west to northwest winds this afternoon
around 25-35 mph behind a compact shortwave passing through the
area. Mostly clear skies continue across southeast WY and western
NE with temperatures in the upper 70s and 80s. A few storms have
begun to develop over the Black Hills this afternoon moving
southeast. These storms could track into portions of Dawes Co, otherwise
precipitation chances are near-zero for the remainder of the CWA. Quasi-
zonal flow with multiple passing shortwaves overtop of the upper
level high centered over AZ/NM will continue Friday. Dry boundary
layers and PW ranging from 0.4-0.6" will limit precipitation
potential, but cannot rule out isolated storm or two developing in
the NE Panhandle Friday afternoon. CAMs are showing disagreement
in coverage, but shows attempts at CI in the 22-00z time frame
with up to 500 J/kg of MLCAPE available. However, latest HRRR and
NAMnest have nearly a 20 degree surface dew point discrepancy
over the northern NE Panhandle Friday afternoon with southerly
flow east of the lee trough. Temperatures will again be in the
80s to low 90s Friday afternoon before a cooler, wetter pattern
arrives for the weekend.
.LONG TERM...(Saturday through Thursday)
Issued at 253 PM MDT Thu Sep 7 2023
A wet weekend into early portions of the work week is expected. A
cold front passes through Saturday and decreases temperatures
significantly for Sunday. Best precipitation chances for Sunday
into Monday as easterly surface flow coupled with a favorable
synoptic pattern enhances lift across the region.
Weak upper-level ridging will be in place across the southwestern
CONUS Saturday and through most of the weekend with near-zonal flow
over Wyoming. A 500mb shortwave pushes through the area Saturday
afternoon and evening with modest cyclonic vorticity advection and
an associated surface low. Surface flow turns easterly with the
passage of this low pressure system Saturday afternoon and evening,
promoting upslope flow across areas east of the Laramie Range. The
surface low drags a modest cold front across the region and drops
temperatures into the 60s and 70s across the CWA for Sunday.
Easterly surface flow continues on Sunday as an upper-level jet
streak develops over the CWA due to tightening height gradients at
250mb. This jetstreak places the region in a favorable location for
synoptic lift. With PW values increasing to nearly an inch in the
Panhandle and nearly 0.80in in southeast Wyoming, enhanced synoptic
lift and surface upslope flow significantly increase precipitation
chances for Sunday. Sunday into Monday looks to be the best day for
widespread precipitation, so kept PoPs near 65-70% for much of the
southeast Wyoming and western Nebraska.
On Monday, an upper-level shortwave pushes into the region from the
northwest and continues the trend of increased precipitation chances
through Monday evening. PW values are lower on Monday for the
Panhandle, with PW values around 0.80in, and similar PW values
across southeast Wyoming. Unsettled weather continues through the
remaining long term as northwest flow develops aloft and daily,
isolated precipitation chances return to the CWA. There is some
disagreement between the GFS and ECMWF after Monday in regards to
the upper-level trough over southern Canada and the northern
Midwest. The ECMWF suggests a more neutrally-tilted trough with a
strong jetstreak, while the GFS likes a broader, positively-tilted
trough with a much smaller jetstreak. While this trough will not
impact the western CONUS directly, the flow to the west of the
trough will. The GFS suggests a weaker, less defined ridge over the
western CONUS with a shortwave trough over the CWA. The ECMWF on the
other hand suggests a stronger ridge in place over the CWA with due
northerly flow overhead. Trended PoPs towards the GFS solution,
which suggests precipitation chances over the CWA, but kept PoPs
very low due to the uncertainty. Kept a weak warming trend from
Monday onward, increasing temperatures only around a few degrees a
day. Will need to continue to monitor long range models to determine
if the GFS or ECMWF solution looks more plausible.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1004 PM MDT Thu Sep 7 2023
Dry westerly flow aloft will prevail.
Wyoming TAFS...Skies will remain mostly clear. Sufficient
gradients will support wind gusts to 25 knots from 15Z to 01Z.
Nebraska TAFS...Skies will remain mostly clear.
&&
.FIRE WEATHER...
Issued at 233 PM MDT Thu Sep 7 2023
Elevated fire weather conditions today with afternoon RHs around
20 percent and gusty west to northwest winds 25-35 MPH. However,
these conditions have not been overlapping with areas were fuels
are ready so no Red Flag Warnings are in effect today. Will see
elevated fire weather conditions again Friday, especially across
Carbon Co through Converse Co with afternoon RHs 10-15 percent.
Could see gusty winds, but should remain below critical
thresholds. The one area to watch will be southwest Carbon Co that
may see occasional gusts to 25 MPH. Precipitation chances increase
headed into the weekend, limiting fire weather concerns.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MB
LONG TERM...AM
AVIATION...RUBIN
FIRE WEATHER...MB
Area Forecast Discussion
National Weather Service Dodge City KS
623 PM CDT Thu Sep 7 2023
...Updated Aviation Discussion...
.SHORT TERM...(This evening through Friday night)
Issued at 128 PM CDT Thu Sep 7 2023
An area of surface low pressure was centered across the Oklahoma
Panhandle early this afternoon with an attendant developing warm
front oriented north to south. There is some surface dew point
enhancement right ahead of this feature, because of a southerly
fetch of higher theta-e air out of Oklahoma, resulting in up to
1500 j/kg CAPE from around DDC south and southeast late this
afternoon. This is completely diurnally driven and will quickly
fade after 00 UTC, with CAMS showing no real attempt at convective
development in that immediate area.
Today will be the hottest day of the week as the warm front and
weak downslope This afternoon aids the full insolation, and winds
weaken the next couple of days. A smoky sky is still in place
across the eastern section of the forecast area and shows up with
HRRR modeled moderate vertically integrated smoke concentrations (
10-30 mg/m2) in the far north and eastern forecast area. This
area of higher concentrations gets washed out I the afternoon with
the changing pattern, and mid to upper jet maximum lifting out of
the region.
.LONG TERM...(Saturday through Thursday)
High confidence (80 percent) exists in a rain event that will
essentially give the entire forecast area measurable rainfall in
the Late Sunday night through Monday time-frame. This will
coincide with what the models and ensembles are showing as break
in the synoptic ridging pattern, as a southwest US zonal jet
impinging on the central Rockies late this weekend, phases with
the deeper cold advection from the northern Plains and a plunge of
cold air into the upper Midwest. Nothing here fits a widespread
severe weather pattern for any timeframe late weekend or early
next week, although any CAPE along the prefrontal trough Saturday
will contribute to a widely scattered (up to 5 percent areal
coverage) hail risk out west of Garden City. The highest
confidence window for rain is after 00 Monday, and through the
overnight, through around the end of the daytime hours on Monday.
The ECMWF and GFS ensemble mean Total QPF plumes support at least
one inch of rainfall for Elkhart, Dodge City and Hays, basically
most of the forecast area. The combination of cool advection and
residual clouds, tempers the ensemble spreads for maximum and
minimum temperatures Monday – as the 25th to 75th percentile Max
Temp is squarely centered in the 60s for afternoon highs at Hays.
Only a gradual adjustments to higher temperatures is being offered
by the ensemble means, but a volatile ensemble spread with the
90th percentile into the mid 80s by Wednesday (almost certain to
be cooler than that).
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 612 PM CDT Thu Sep 7 2023
At 23z Thursday multiple surface boundaries were located across
southwest Kansas which were resulting in variable winds at 10
knots or less. These variable winds will continue into the evening
hours but will gradually become more easterly at less than 10
knots by 03z Friday. East winds at less than 10 knots overnight
will increase into the 10 to 15 knot range between 15z and 18z
Friday. Later shifts will need to monitor the potential for a
return of reduced visibility (4-5sm) due to smoke after 09z Friday
if the HRRR near-surface smoke is correct. At this time
confidence is less than 50% of this occurring so did not
introduce any reduction in visibility in the 00z TAFS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 62 93 61 91 / 0 0 0 10
GCK 60 91 60 89 / 0 0 0 10
EHA 59 93 60 91 / 0 0 0 10
LBL 59 93 59 91 / 0 0 0 10
HYS 60 90 60 91 / 10 0 0 10
P28 66 93 63 91 / 10 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Burgert
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
658 PM CDT Thu Sep 7 2023
.Discussion...
Issued at 154 PM CDT THU SEP 7 2023
Key Messages:
-Unhealthy air quality expected this afternoon due to smoke from
Canadian wildfires. Conditions expected to improve after sunset.
-Mainly quiet forecast with highs mainly in the 80s through the
weekend
-Low end chance for some showers and thunderstorms this evening and
overnight but most will stay dry
Details:
Today our weather will continue to be dominated a ridging across
the western United States. At the surface, a high pressure across
Manitoba has pushed south into the region, allowing for light
northeasterly winds and a dry airmass today. Hazy conditions will
continue to be a concern through the afternoon with Canadian
wildfire smoke continuing across the region. With high pressure in
places, expect this smoke to make it to the surface today. This is in
agreement with the HRRR smoke model showing highest smoke
concentrations at the surface and 1000 feet. With surface smoke,
expect air quality to be moderate to unhealthy across the CWA.
Impacts may be especially felt for sensitive groups. Outside of
smoke concerns, expect a quiet weather day with highs in the low
to mid 80s and light winds through the afternoon. Smoke conditions
will improve this evening and overnight.
Overnight a weak mid level shortwave will round the ridge bringing
chances for shower and thunderstorms across Nebraska. CAMs continue
to indicate low end chances for some isolated showers or a
thunderstorms moving into northern parts of the area. In general
though, its more likely that most will stay dry with drier air in
place tonight. Additionally, strong storm potential is not
expected with limited instability, but lower end wind gusts may
still be possible within any shower or storm. Otherwise expect
this activity to diminish by Friday morning.
A fairly stagnant upper pattern will be in place for the remainder
of the week into the weekend. The upper ridging will have little
movement with a few shortwaves passing through this weekend and into
next week. This will bring a few low end chances of precipitation
chances Sunday into early next week. Temperatures are expected to be
mild Friday through Sunday topping out in the low to mid 80s each
day. We may finally see the pattern shift Monday into Tuesday as
troughing across Canada sinks south pushing a cold front through the
area, bringing better potential for precipitation and cooler
temperatures next week. Highs next week are expected to be below
normal and in the 70s into the mid week.
&&
.Aviation...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 627 PM CDT THU SEP 7 2023
Hazy conditions are expected to last a little past midnight. Winds
will be weak from the east around 0-5kts for the duration of the TAF
period. Current satellite imagery shows a layer of clouds around
10,000 ft moving towards eastern KS and western MO.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...HB
Aviation...Collier
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
722 PM CDT Thu Sep 7 2023
...Aviation Update...
.DISCUSSION...(This evening through Thursday)
Issued at 450 PM CDT Thu Sep 7 2023
Key Messages:
* Poor air quality will continue to impact the region for about
another 24 hours, or so.
* There is a Marginal Risk for a few severe thunderstorms this
evening into early overnight, mainly north of the Tri-Cities.
* A stronger storm system will bring better and more widespread
rain and thunderstorm chances this weekend into early next week.
Once again, there is a Marginal Risk for a few severe
thunderstorms with the initial cold front Saturday afternoon and
evening.
* Expect much cooler and more fall-like temperatures for the brunt
of next week.
Forecast Details:
It`s been a fairly quiet and warm day across the area thus far,
though once again on the smokey/hazy side. Visibility has been
reduced to 4-5sm in spots, even this aftn despite better mixing,
and PM 2.5 levels remain in the "Unhealthy" category per the NDOT
sensor near GI. 12Z HRRR backed off of bringing any significant
relief to the area today or tonight as it appears any push of
cleaner air remains W of the area this aftn, and any tstm
development remains fairly spotty/limited tonight. Thus, after
collaboration with surrounding offices and NDEE, the Air Quality
Alert has been extended into Fri aftn. Hopefully by then
additional mixing and incr deep layer flow will be enough to see
improving conditions at the surface.
Tstm chcs will be on the incr this eve, at least for N portions of
the CWA, as a quick moving disturbance slides through the area.
Tstm chcs look to stem from two main areas/regimes:
1)southward extension/development of WAA-driven activity currently
running from around Sioux Falls to Norfolk and 2)within field of
agitated CU in hot/deeply mixed environment over NW Sandhills. The
former area could pose a risk anytime within next few hrs, with
the later area probably not affecting far NW zones until after
~01Z per latest HRRR trends. There remains a Marginal Risk of
severe per SPC, though the areal coverage has decr compared to
earlier outlooks. Deep layer shear is strong thanks to veering in
low to mid levels and decent H5 speed max, but instability is
certainly lacking given dew points only in the 50s. Latest CAMs
suggest main window being 01Z to 05Z and limited to areas mainly N
of the Tri-Cities. Marginally severe hail would probably be the
main threat, though gusty winds can`t be ruled out.
Quiet, but warm, conditions are expected Fri into Fri night with
aftn high temps ranging from mid 80s to low 90s. Should be great
early-fall conditions for area football games Fri eve as temps
fall back from the low 80s around 7PM to upper 60s to 70s by 10PM
amidst light winds and improving air quality.
Pattern becomes more active this weekend as a decent trough moves
into the Great Lakes region and forces a cold front into central
Plains. The initial arrival of the sfc front looks to be into NW
zones at some point Sat aftn-eve and perhaps provide enough
forcing for scat sfc based tstms. Models are somewhat mixed with
this potential as low level moisture again looks to be lacking.
Areas ahead of the front will see warm conditions once again, and
gut feeling is that magnitude of mixing combined with decent sfc
convergence invof low pressure/triple point somewhere near/just W
of far W CWA, will indeed be enough to spark some sct tstms after
21Z. Deep layer shear should be sufficient for svr activity given
substantial veering with height and at least modest H7-H5 wrly
flow ~30kt, with overall instability again being potential
limiting factor. Some models suggest a potentially narrow tongue
of enhanced low level moisture immediately ahead of/SE of
aforementioned triple point, which if it indeed pans out could
lead to a few hr window for somewhat enhanced svr threat over far
W/NW zones, but confidence on these details is still limited.
None of the models barrel the front through the area Sat night and
instead keep a nearly stationary boundary draped across at least
portions of the CWA through the remainder of the weekend. Thus,
would expect iso-scat tstms to continue and/or redevelop off and
on Sun into Sun night. Models have even lesser instability on Sun
due to incr poor mid level lapse rates - so anything more than
iso/marginal svr threat appears unlikely at this time. Models
suggest overall-greatest shwr/tstm chcs/coverage should come Sun
aftn into Sun night, esp. for areas W and S of Tri-Cities, as
additional upper level support in the form of coupled upper jet,
deep layer frontogenesis, and mid level height falls overspread
the area. Am a bit concerned models are over-doing the the NE
extent of pcpn (which would include the Tri-Cities N and E) as
sometimes these types of events tend to "hug" the higher terrain
further W and low level dry air filters in from the NE.
Nonetheless, looks to be the best rain chcs most of the CWA has
seen in quite some time.
Should see gradual drying trend on Mon as upper trough continues
to dig through N Plains/Upper MS Valley and force the front even
further S/SE. Other than perhaps a return of Canadian smoke (???),
the biggest story next week will be the much cooler and more
fall-like temperatures with highs in the upper 60s-70s and lows in
the upper 40s-50s (possibly even low 40s(!) Tue AM for mainly
areas like LXN to ODX) expected each day. Assuming smoke doesn`t
become a significant issue in the cool Nrly flow, should see
prolonged period of excellent conditions for outdoor activities
next week.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 721 PM CDT Thu Sep 7 2023
- General overview:
High confidence in VFR ceiling throughout the period and and
rain/thunderstorm-free conditions through at least the vast
majority of the period. That leaves the following primary 3
concerns: 1) reduced visibility from Canadian wildfire smoke
(MVFR probable through much of the period)...2) at least a brief
window- of- opportunity for a passing thunderstorm this evening
(especially at KGRI), which could yield gusty outflow winds and
perhaps small hail...3) Even if no thunderstorms directly affect
KGRI/KEAR and remain off to the north (currently deemed the most
favorable scenario), there are increasing signs that an outflow
boundary could arrive later this evening and "disrupt" the
prevailing wind field with a few hours of more northerly winds.
- Wildfire-smoke related visibility details:
Although KEAR is starting off high-end VFR, based on nearby obs
and best-available model data (honestly this is more of a "best
guess" given that models are struggling in this unusual smoke
regime), expect MVFR to prevail through most of the first 18 hours
of the period at both sites. Have indicated a return to low-end
VFR for the final 6 hours Friday afternoon as gradual improvement
in low-level smoke concentration continues...but again this is not
an overly-high confidence situation.
- Thunderstorm details:
Although some of the latest/usually-reliable short-term model data
keep any isolated/scattered thunderstorm activity this evening at
least 30-50 miles north of KGRI/KEAR, it appears that it could be
just enough of a "close call" for KGRI that decided to introduce
a generic "vicinity thunderstorm" (VCTS) 03-06Z, with KEAR looking
"safer" and thus have kept VCTS out for now. IF any storms do
directly impact especially KGRI, gusty outflow winds of 30+KT and
perhaps small hail cannot be ruled out.
- Winds:
Aside from any possible thunderstorm outflow-related influences,
winds should not be a significant concern, with the vast majority
of the period likely to feature sustained speeds near-to-below
10KT out of a southeasterly or easterly direction. However, there
are signs that especially the 04-06Z time frame this evening
could feature the arrival of a convective outflow boundary that
could abruptly shifts winds to some variation of northerly, with
at least brief gusts of 20+KT possible. This is currently not
reflected in 00Z TAFs, but will monitor upstream obs/trends for
possible amendments.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Thies
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Goodland KS
900 PM MDT Thu Sep 7 2023
.SHORT TERM...(This evening through Saturday night)
Issued at 244 PM MDT Thu Sep 7 2023
Across the region this afternoon, skies are sunny with some filtered
sunshine in eastern locales. Temperatures as of 200 PM MDT are
ranging in the upper 80s into the mid 90s. With a dryline/boundary
slowly trudging eastward from Colorado, winds are split over the
area with southerly flow east of Highway 27 and northerly flow
along/west of Highway 27. Gusts around 25 mph have been occurring.
For the remainder of the afternoon, the main wx concerns will focus
on the potential for a few hours of elevated/near critical fire wx
conditions over northeast Colorado and adjacent KS/NE counties.
Dewpts are about 10-15 degrees less than those locales east of the
boundary. Continued drying on the northerly fetch will occur through
sunset, with isolated spots approaching 25 mph or higher. While
there could be a few isolated areas that could hit criteria, it may
only occur for an hour or so.
For this evening, conditions will decrease out west. For the east, a
few hours of some lingering patchy smoke are possible, but the
latest RAP NCEP smoke guidance shows only far E/NE zones to be
impacted, but only to 5-6sm visibility reduction.
Going into Friday, guidance continues placement of the upper ridge
over the southern Plains, giving the CWA zonal flow aloft. At the
surface, models show a low forming south of the CWA will amplify
into the eastern Colorado region late in the day. Northerly flow
over the area in the morning will eventually shift to an east-
southeast fetch by late afternoon. Above normal warmth will continue
area-wide as a result. Areas Highway 27 and west will see low RH
readings through the day, but winds below Red Flag criteria. As a
result looking for a few hours of elevated conditions.
For the late afternoon hours into the evening timeframe, the switch
to a southerly flow will push increased low level moisture into the
CWA from east to west. The amplified inverted trough over eastern
Colorado will begin to move east into the Plains during the evening.
The increased moisture and instability along the boundary could
trigger a few isolated rw/trw for NW zones through 06z Saturday.
Elevated, inverted-V soundings bring DCape into the 1500-1600 j/kg
range. Some limited SBCape/MUCape, but any storms looked to be
elevated with a wind threat should storms occur.
Going into Saturday, upper ridge shifts slightly westward, allowing
a shortwave to pass through the region. This, in tandem with the
aforementioned surface trough/boundary that meanders slowly E/SE,
with trigger a round of rw/trw. Model soundings show potential for
severe storms as SBCape/MUCape around 3000 j/kg around 00z Sunday
and DCape 1500-1600 j/kg. SPC does have the much of the CWA under a
Marginal risk w/ wind/hail threats. On top of this, the southerly
flow ahead of the front will bring in ample low level moisture as PW
values will approach 1-1.4" especially for eastern locales,
resulting in potentially locally heavy rainfall and so flash
flooding threat will have to be monitored. These conditions expected
to persist into the evening hours.
For temps, above normal warmth expected over the region in the short
term. Looking for daytime highs to top off in the upper 80s to the
mid 90s. Overnight lows will have a range from the mid 50s to mid
60s, with the warmest timeframe on Friday night ahead of expected
precip to start off the weekend.
.LONG TERM...(Sunday through Thursday)
Issued at 259 PM MDT Thu Sep 7 2023
At the beginning of the long term period, forecast guidance depicts
the CWA having a westerly flow aloft being underneath an upper air
ridge over the southwestern CONUS with an upper air trough over the
southeastern CONUS on Sunday morning. Models then project a
shortwave disturbance making its way over the CWA on Sunday evening
though keeping the overall ridge-trough pattern. Going through
Monday, models show a weak trough over the CWA during the morning
hours. This trough looks to be absorbed within the base of a
larger positively tilted upper trough over eastern Canada/Great
Lakes/Northern Plains regions during the evening hours as the
CWA`s upper air flow turns more west-northwesterly. Long term
models start to diverge from their solutions crossing into Tuesday
as the ECMWF has the trough axis passing over the CWA in the
early morning hours while the GFS delays it until late Tuesday
with both models showing a positively tilted ridge building behind
it over the Northern Plains. The GFS shows another evening upper
air shortwave just west of the CWA in its solution. The
differences in the upper air pattern compound on Wednesday with
ECMWF showing a ridge moving over the CWA while the GFS has the
CWA more underneath the backside of trough now over the Great
Lakes. The uncertainty between long term models grows on Thursday
as the GFS shows a northwesterly flow over the CWA throughout the
day being between a western ridge and an eastern trough while
ECMWF shows the CWA between the eastern trough and another weaker
trough over the Rocky Mountains. Will monitor future model runs
going forward to see which solution becomes the favorite as there
is a good amount of uncertainty particularly in the later days of
the long term period.
Precipitation chances continue to be seen each day with Sunday
appearing to have the best chances as models show a cold front
passing through the region. Long term models continue to show
PWAT values around 1 to 1.5 inches within the region while
current QPF looks to range between to 0.25 and 1.25 inches. Upon
looking at model convective parameters for Sunday, latest runs
show some areas having of SBCAPE over 1000 J/kg with most of the
CWA having bulk shear values over 40 kts. However, there still
looks to be a good amount of CIN in the region though it may have
come down slightly. Will continue to monitor for both heavy
rainfall and severe weather potential going forward. Precipitation
chances do look to continue into Monday though tapering off going
through the day and ending overnight. Convective parameters do
not look as impressive as those on Sunday with bulk shear values
around 35 kts and SBCAPE staying in the triple digits at best.
Additional QPF looks to be around a few tenths at most on Monday.
Precipitation chances are also seen through the rest of the week,
but chances look to be lower due to the uncertainty seen in the
upper air pattern at this time. Fire weather is not expected to be
a concern within the long term period with these precipitation
chances as well as below normal temperatures expected.
Daytime highs for the Tri-State Area on Sunday look to range between
the middle 70s and lower 80s followed by cooler highs on Monday in
the middle 60s to lower 70s range behind the cold front passage.
Tuesday`s daytime highs expect to be in the upper 60s to lower 70s
range while Wednesday`s highs are forecasted to be in the lower to
middle 70s. Thursday`s daytime highs are slightly warmer being in
the middle to upper 70s. Overnight lows for the long term period
look to range between the middle 40s and middle 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 900 PM MDT Thu Sep 7 2023
KGLD...VFR conditions are expected through the period. A light and
variable wind at taf issuance will continue through sunrise Friday
morning. Northwest winds under 10kts at 13z steadily veer to the
northeast, east, southeast and south through the remainder of the
period at speeds up to 10kts. .
KMCK...VFR conditions are expected. Light and variable winds at
taf issuance will continue through 22z, establishing a
southeasterly component at speeds around 7kts after 23z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...JN
LONG TERM...076
AVIATION...99
Area Forecast Discussion
National Weather Service Gray ME
1140 PM EDT Thu Sep 7 2023
.SYNOPSIS...
Warm and humid conditions continue into the weekend as a slow moving
front approaches from the west. There will be rounds of showers and
thunderstorms moving into the area starting this afternoon through
the weekend. Some storms may become strong to severe with the
greatest risk for severe storms Friday. Temperatures trend downwards
late in the weekend into next week while a stalled front over the
area will keep conditions unsettled.
&&
.NEAR TERM /OVERNIGHT/...
1140 PM Update...Another update to tighten up the PoP forecast
over the next several hours with a decaying convective complex
tracking through central NH. Also of note is marine fog
developing Downeast... with the expectation that this continues
to develop and at some point advect into the Midcoast.
638 PM Update...Mainly tighten up PoP through the next few
hours, keeping most activity up along the international border.
Looking upstream, scattered showers and storms are on track to
miss us to the east, or at best clip the upper Connecticut River
Valley. There remains however a large MCS trucking through the
Susquehanna River Valley, which is on track to come into New
England later this evening as it weakens.
Previously...
Difficult forecast for this evening and overnight revolving
around convection.
Most certain will be temps remain well above normal for this
time of year...with widespread upper 60s and lower 70s.
Currently a bowing line of storms has developed in the Champlain
Valley and is propagating northeast. Hi-res forecasts continue
this motion...and the bulk of the convection should miss the
northern zones. If the tail end can start backbuilding that may
bring more of the North Country and western Maine mtns into
play. I do have a small area of gusty winds tagged to the
thunderstorms around Moosehead Lake for this after 8 PM. In the
meantime isolated storms will continue to percolate in the mtns.
This activity is mainly driven by diurnal heating...so they are
expected to diminish in coverage thru sunset.
More likely is that the large cluster of storms over PA and NY
will continue lifting northeast and move into parts of the
forecast area near midnight. Given how mild it will be overnight
some gusty winds will remain possible with this complex.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Another steamy start to the day will give way to growing
chances for showers and storms by midday. Hi-res guidance is
pretty bullish on coverage...especially across the southern half
of the forecast area that is expected to miss out on the action
tonight. CSU machine learning guidance is also fairly bullish
on storm strength...and SPC HREF updraft helicity has higher
probabilities than this afternoon and overnight. So I anticipate
the severe threat Fri will be higher than today...and SPC seems
to agree as they have upgraded much of the area to slight risk.
As such I included gusty winds for most of the area...expanding
with time northeast thru the afternoon. Shear is forecast to be
a little bit on the marginal side...and hodographs forecast to
be fairly straight. This suggests that storms may be pulse
variety. While wind is the primary hazard...some hail cannot be
ruled out.
Fri night will be another mild one but not quite as mild as
tonight. Both marine fog and valley fog will be
possible...especially in areas that receive rain.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
Overview: Mainly unsettled weather is anticipated through the
weekend and well into next week. Temperatures will cool down to
the climatological average by the end of the weekend and will
make for a cooler, but still humid start to next week.
Details: Saturday will start off as warm and humid with morning
low temperatures in the upper 60s and low 70s. Daytime heating
will allow for CAPE to build to around 1500 J/kg by late
morning. There is some uncertainty as to where the best
instability will develop as a front will likely be stalled SW to
NE across the area leading to clouds. This front will provide a
focus for thunderstorms to develop through the day Saturday and
with deep layer shear to around 30 kts there will be potential
for strong to severe storms. Additionally, with PWATs over the
90th percentile, some storms could have some heavy downpours
associated with them. Heavy downpours in tandem with a nearly
stationary boundary could lead to a few locations receiving
excessive rainfall and localized flash flooding is possible.
A trough axis will remain to the west of New England into the
middle of next week for continued unsettled weather. While
temperatures will not be as warm, PWATs will remain high increasing
the concern for continued bouts of heavy rain. Much like this
summer, places that see repeated rounds of heavy rain will be at
risk for flash flooding. WPC does place the entire forecast
area in a Marginal Risk for excessive rainfall Monday, which is
reasonable given the high PWATs and likely wet antecedent
conditions. Thereafter, there may be a bit of a break Tuesday as
the trough to the west flattens and takes on a positive tilt.
The trough then deepens around Wednesday sending a frontal
system into the Northeast.
&&
.AVIATION /04Z FRIDAY THROUGH TUESDAY/...
Short Term...Widespread VFR conditions this afternoon will give
way to deteriorating conditions tonight...especially near the
coast. Some marine fog/stratus is expected to develop
overnight...with IFR or lower conditions. I also anticipate that
some convection will move into western NH late tonight. This may
impact both LEB and HIE and I have added a PROB30 for both sites
with timing based around the latest range of HRRR forecasts.
These storms may disrupt the diurnal trend of valley fog for
both sites too. More widespread SHRA/TSRA are expected starting
Fri midday. Local IFR or lower conditions are possible in any
storm...but confidence is low on timing and location.
Long Term...Scattered showers and thunderstorms through the
weekend and early next week could bring periods flight
restrictions. The pattern will also favor night time fog which
will also bring flight restrictions. Generally calm and variable
winds are anticipated everywhere except if strong thunderstorms
cross a TAF site.
&&
.MARINE...
Short Term...Winds remain onshore into the weekend...but are
forecast to remain below SCA thresholds. That warm/moist
advection will make marine fog and stratus more likely starting
tonight. Some low visibilities are possible nearshore.
Thunderstorms are expected to stay northwest of the waters
tonight...but starting midday Fri they will become more likely.
Any storms may bring gusty winds to the waters.
Long Term...
Winds and seas will remain below SCA thresholds through the
weekend with persistent southerly to southeasterly flow.
Persistent southerly flow will also bring periods of fog over
the waters. By late Monday seas will build to around 5 feet
along the outer waters.
&&
.CLIMATE...
Warm and humid conditions will continue into Friday. Below is a
summary of daily records at local climate sites.
Fri 9/8
PORTLAND
Max high: 93F (1960)
Warm low: 70F (2015)
CONCORD
Max high: 96F (1872)
Warm low: 68F (1936)
AUGUSTA
Max high: 92F (2002)
Warm low: 71F (2015)
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
UPDATE...Casey
NEAR/SHORT TERM...Legro
LONG TERM...Palmer/Schroeter
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1042 PM CDT Thu Sep 7 2023
.SHORT TERM... (Through Late Friday Night)
Issued at 211 PM CDT Thu Sep 7 2023
KEY MESSAGES:
1) Confidence is high (>90%) in temperatures remaining at or below
climatological normals through the forecast period.
2) While there is a low chance (30-40%) of rainfall early next week,
a majority of the forecast period will remain dry.
Current water vapor imagery shows northwesterly flow over the CWA on
the western periphery of an upper-level trough, with a shortwave
departing the region and moving into the Southeast. At the surface,
surface observations show an elongated area of high pressure
extending from the Upper Midwest southward along the Missouri River
Valley. This pattern has allowed for a seasonable air mass to move
into the Middle Mississippi Valley, with most locations this
afternoon seeing temperatures top out in the low 70s to low 80s.
The cooler temperatures in that range are expected over portion of
Illinois where denser cloud cover has inhibited surface heating.
Of additional note today is smoke from Canadian wild fires mixing
down to the surface, causing reduced visibilities this morning and a
hazy sky. Local observations have shown visibilities improving area-
wide through the day thus far, and the HRRR continues to show the
smoke plume thinning and shifting westward through this evening and
overnight. Therefore, another round of near-surface smoke is not
expected in the near term.
Tonight, another round of patchy fog is expected across the area,
especially in river valleys, as temperatures cool into the mid 50s
to low 60s for overnight lows beneath mostly clear skies.
Toward daybreak and into the day tomorrow, a shortwave currently
seen in water vapor imagery over South Dakota and Nebraska is
expected to move directly over the area. Some CAMs have widely
scattered convection occurring with this shortwave. However,
confidence in rain occurring with this shortwave is very low, as
model soundings show dry low to mid levels. Therefore, only mid to
upper- level clouds are expected the passage of the shortwave, and
I`ve maintained a dry forecast. Otherwise, nearly identical
conditions are expected across the CWA tomorrow as are being
experienced today.
Elmore
.LONG TERM... (Saturday through Next Thursday)
Issued at 211 PM CDT Thu Sep 7 2023
On Saturday, ensemble consensus is that weak upper-level troughing
will remain over the eastern U.S. as a ridge holds over the
Southwest with northwesterly flow holding over the CWA. Ensemble
clusters have this general upper-level pattern holding in place
through the middle of next week. The main focus for variability in
this pattern comes early next week as the through looks to
deepen, sending a cold front through the Midwest. Guidance varies
on the phasing of the trough, leading to uncertainty in the FROPA
timing. Earlier solutions have a Monday FROPA, while slower
solutions have it moving through the CWA on Tuesday. Rain chances
with the front look low, with ensembles showing the probability of
measurable rainfall (0.01") toping out at 30-40% through that
time frame. Areas that do see rain will likely see roughly a
couple of tenths, as the 75th percentile for most locations across
the CWA tops out around 0.25".
Behind the front, ensemble means show temperatures dropping to
around 10 degrees below climatological normals for the mid-week
period. If this holds, this post-frontal airmass will be the CWA`s
first taste of fall-like temperatures, as highs top out around 70
and lows drop into the 50s.
Elmore
&&
.AVIATION... (For the 06z TAFs through 06z Friday Night)
Issued at 1041 PM CDT Thu Sep 7 2023
Isolated showers associated with a weak shortwave are diminishing
due to drier air over forecast area. So just expect increasing mid
and high clouds through the rest of the overnight hours. Otherwise,
light and variable winds will pickup from the north by mid morning
on Friday with scattered diurnal cu developing. Still expect some
patchy river valley fog, especially at KSUS between 08z and 13z
Friday.
Byrd
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Phoenix AZ
444 PM MST Thu Sep 7 2023
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Strengthening high pressure across Arizona into the weekend will
result in a continued warming trend and dry conditions. An
Excessive Heat Warning is in effect Saturday and Sunday due to
widespread Major HeatRisk and record breaking temperatures. Next
week, temperatures will trend lower with increasing storm chances
across the Arizona higher terrain.
&&
.DISCUSSION...
Upper level high pressure centered over southern NM, will
strengthen and build westward across the region into this
weekend. This will result in limited shower/storm potential and a
continued warming trend.
Latest satellite imagery showing clear skies for most areas, but
just a hint at clouds/moisture across SE AZ. There is just enough
moisture working around the west side of the high for a few
clouds and isolated showers drifting north. HRRR showing the
possibility of a few showers into Friday, mainly across the
higher terrain north and east of Phoenix. Instability is very
limited so activity will be weak and isolated at best.
As the high pressure builds across the area over the weekend,
temperatures will heat up and convection will be suppressed. The
current excessive Heat Warning for Sat/Sun is on track with
temperatures back above 110 for many areas with widespread major
HeatRisk with readings some 10 degrees above normal. In Phoenix
specifically, both days are forecast to beat the daily records of
111F (set in 2021 and 1990 respectively). The record number of
days with 110+F highs in a year remains at 53 days set in 2020,
which will also likely be broken by Sunday.
For next week, ensembles in good agreement that the upper high
will be suppressed south of the area with westerlies developing.
This will result in temperatures slowly lowering closer to normal
levels. A weak impulse in the flow combined with an increase of
moisture (some the result of Hurricane Jova remnants) Tuesday into
Wednesday will bring an increase in shower/storm chances to AZ.
Most of the activity should be confined to areas north and east of
Phoenix. This brief surge of moisture will leave the region by
the end of the week, for mostly dry conditions returning.
&&
.AVIATION...Updated at 2344Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
No aviation weather concerns are expected through the TAF period.
Winds will continue to favor light and diurnal tendencies with
some afternoon breezes and periods of variability overnight. FEW-
SCT mid-level clouds around 15 kft will continue throughout the
period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation weather concerns are expected through the next 24
hours. Winds will favor light, diurnal tendencies with extended
periods of variability. Otherwise, mostly clear skies will persist
through the rest of today before FEW-SCT mid-level clouds around
15 kft filter in tomorrow morning.
&&
.FIRE WEATHER...
Very hot conditions will return for the weekend, with temperatures
warming some 10 degrees above normal. Relative humidities will
bottom out at or below 10 percent with poor overnight recoveries.
Humidities will increase slightly heading into early next week as
moisture increases along with the chance for more clouds and
scattered showers/storms, especially Tuesday into Wednesday. The
best chance for rainfall will be in eastern and higher elevation
zones. Temperatures next week will return to near normal levels.
Winds will continue to follow familiar diurnal tendencies with
some occasional afternoon upslope breeziness.
&&
.CLIMATE...
Record highs:
Date Phoenix Yuma El Centro
---- ------- ---- ---------
Sep 8 110 in 1979 115 in 1979 114 in 2018
Sep 9 111 in 2021 113 in 1990 115 in 1968
Sep 10 111 in 1990 114 in 1979 113 in 1971
Sep 11 112 in 1990 116 in 1990 115 in 1971
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning from 10 AM Saturday to 8 PM MST Sunday
for AZZ530>556-559>562.
CA...Excessive Heat Warning from 10 AM Saturday to 8 PM PDT Sunday
for CAZ562>567-569-570.
&&
$$
DISCUSSION...Frieders
AVIATION...Smith
FIRE WEATHER...Frieders
CLIMATE...18