Forecast Discussions mentioning any of
"ACARS" "MDCRS" "AIRCRAFT" "TAMDAR" "AMDAR" "WVSS" received at GSD on 07/24/23
Area Forecast Discussion
National Weather Service Indianapolis IN
1030 PM EDT Sun Jul 23 2023
.Forecast Update...
Issued at 1029 PM EDT Sun Jul 23 2023
There are still some isolated showers and thunderstorms lingering
within central Indiana this evening along a weak remnant boundary.
These will continue to percolate as they move SSE along the boundary
through 04-06Z.
New development of showers and thunderstorms is still possible this
evening north of a modest jet streak. Any showers/thunderstorms that
due develop should stay under severe criteria with the only threats
being lightning and occasional high rain rates leading to localized
areal flooding.
Otherwise, no major changes needed to the ongoing forecast other
than fine tuning of POPs and associated sky cover forecast.
&&
.Short Term...(This evening through Monday)
Issued at 254 PM EDT Sun Jul 23 2023
Rest of Today.
As of early this afternoon, the MCV that helped bring a few showers
to the northern counties this morning was crossing into Illinois.
Convective temperatures have been met according to ACARs soundings
with 1200-1500 J/kg of SB CAPE, but a fairly dry column is limiting
the effective instability with only 200-300 J/kg when looking at ML
CAPE. The best forcing into the afternoon will be near and to the
south of the exiting MCV, so will focus POPs across the eastern
counties with lesser amounts further to the west. The last few HRRR
runs have latched onto the exiting MCV and each successive run
continues to lower rain chances across central Indiana with a lack
of a good initiator for convection.
Tonight.
Generally conditions are expected for the overnight hours with the
potnetial for a few additional showers and storms along an
instability gradient across central Indiana. The diurnally driven cu
field overhead will gradually dissipate after sunset as the PBL
begins to decouple. With the lower expected coverage for storms
this afternoon, little convective overturning will create a slightly
more favorable environment for a few elevated showers and storms.
Initiation for these storms will be along the eastern periphery of a
slightly stronger 700-850mb jet which will peak in strength after
midnight. Not expecting high coverage or anything more than a few
rumbles of thunder, but will be worth watching through the night.
Shallow ground fog looks to return again late tonight into tomorrow
morning with similar model signals to the last few morning with
mostly clear skies, calm winds, strong inversion, but marginal
moisture.
Monday.
The pattern will gradually begin to shift tomorrow with warmer
weather working its way into central Indiana. Dry weather is
expected for much if not all of central Indiana through the morning
hours, but more robust southerly flow will bring dewpoints into the
70s along with warmer temperatures along with renewed rain chances.
Model soundings show upwards of 2000 J/kg of instability during peak
heating, but a lack of initiation source will limit convective
development and coverage for storms. Models may also be overdoing
the afternoon heating with the ridge still well out to the west and
weak northwesterly flow aloft through the daytime hours.
&&
.Long Term...(Monday night through Sunday)
Issued at 254 PM EDT Sun Jul 23 2023
* Hottest weather of the summer thus far later this week.
* Frequent but low chances for thunderstorms through the week.
Continued expectations for this week are for a very large upper
level ridge centered over the Southwest/southern High Plains, with
upper level troughing of various intensities over the northeastern
US, with central Indiana stuck in between in an upper level
northwest flow regime much of the week.
Surface flow will be largely southerly or southwesterly much of the
period, with warm advection maintaining a hotter and more humid
airmass through the week, at least until potential passage of a cold
front very late in the period.
As a result of this northwest flow aloft and warm, moist southerly
flow at the surface, frequent chances for thunderstorms will be
required through much of the long term period, but any one period
will not have more than low chances, owing to significant
uncertainty with respect to convective evolution, as the resultant
forecast depends both upon subtle disturbances that longer range
models generally handle poorly, and evolution of prior convection,
which models also struggle with significantly.
By mid week, afternoon highs in the low to mid 90s will be
commonplace, with peak heat index values approaching or exceeding
100 degrees at times. This is unlikely to rise to the level of
headline necessity, but will be quite hot and sticky, particularly
given the relative lack of such heat thus far this season. It is
also worth noting that heat illness is possible even with similar or
lower heat index values, particularly with prolonged exposure or in
those who are particularly susceptible.
Folks across central Indiana should take care to limit heat exposure
this week and take frequent breaks when this is not possible.
&&
.Aviation...(00Z TAF Issuance)
Issued at 702 PM EDT Sun Jul 23 2023
Impacts:
-Isolated VCTS at KBMG through 02Z.
-MVFR vsbys from 10Z to 13Z.
Discussion:
Clouds and any lingering showers/thunderstorms will then clear after
sunset. Winds will remain light and variable through the period with
a predominantly southerly direction. Patchy fog with MVFR vsbys will
return late tonight and continue through the early morning hours.
More thunderstorms are possible beginning around 22Z tomorrow
afternoon through the evening, primarily near KBMG, KHUF and KIND.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...Updike
Short Term...White
Long Term...Nield
Aviation...Updike
As discussed in previous forecast discussions, tomorrow night
continues to trend drier. While an 925-850mb LLJ is expected to
develop across the mid-Mississippi River Valley, forecast model
guidance continues to show the development of a warm frontal zone
well southwest of our area (central Iowa to west-central Illinois),
which should focus nocturnal convective development outside our
area. Notwithstanding a big adjustment in the forecast position of
the front, we favor a dry night. Overnight lows will drop into the
mid 60s overnight.
Borchardt
&&
.LONG TERM...
Issued at 307 PM CDT Sun Jul 23 2023
Tuesday through Sunday...
The main story through mid-week into the upcoming weekend is the
development of warm and humid conditions with several conditional
periods of convection within the periphery of a "ring-of-fire"
pattern. While the impressive stretch of oppressive heat across
the southwest CONUS the past couple weeks will migrate eastward
with the an upper ridge, the placement of the core of the ridge
(central High Plains) and shape (broad with somewhat zonal flow
across the northern CONUS) continues to put doubt on how far north
and east the more significant heat will reach.
In the absence of active convection this far south late in the
week, Thursday and especially Friday will be some of the warmest
(heat index) conditions so far this year. Heat index values may
reach Heat Advisory criteria (105F) in portions of the area,
particularly Friday. But, strengthening mid and upper-level flow
through the northern CONUS on the continued edge of steeper mid-
level lapse rates and increasing ET/Gulf moisture through the
region will set the stage for successive rounds of active
convection from the northern Great Plains into the Great Lakes
region mid to late week.
At this time, an initial trough on Wednesday may bring the first
round of convection. Focus will then be on potential MCS activity
developing well northwest of the CWA on Thursday, with upstream
trends dictating storm chances into our area Thursday night and
wherever any effective outflow focuses new convection Friday and
Saturday. Will maintain generally slight chance or chance PoPs
through much of the period while still remaining slightly
conservative with temps Friday and Saturday.
Kluber
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Lake breeze wind shifts both this evening (?) and Monday
afternoon.
Despite weak wind surface wind field in baggy surface pressure
gradient this afternoon, Lake Michigan lake breeze has struggled
to push inland toward KORD/KMDW. Current TORD radar data shows
the boundary only about 7 miles east of KORD and perhaps 3 miles
east of KMDW and still moving very slowly west, though lack of a
more solid push will definitely make for a late (01-02Z) passage.
With lake breeze arrival near sunset, winds may tend to just go
light and variable, which they should do after dark either way.
Weak surface ridge across northern IL Monday looks to support an
evening weaker synoptic wind field, which should allow the lake
breeze to make both KORD and KMDW in the afternoon. Did push the
timing back an hour from previous forecast however, based on
latest HRRR guidance. East-southeast winds should remain light
southeast into Monday evening.
Otherwise, VFR conditions are expected through the period. May be
some shallow patchy fog south of the terminals, but none expected
at the forecast sites.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Lubbock TX
610 PM CDT Sun Jul 23 2023
...New AVIATION...
.SHORT TERM...
(This evening through Monday)
Issued at 211 PM CDT Sun Jul 23 2023
A 597 dam upper level high, positioned over the Four Corners, will
continue to support northerly flow aloft for West Texas. With height
increases expected across the CWA given the eastward shift in the
center of the high, warmer temperatures are expected this afternoon
into overnight. Lows are projected to be slightly warmer than
previous nights in the low to mid 70s.
A much quieter day Monday as heights continue to increase over West
Texas. A surface low near the lee of the Rockies will drive winds
out of the southwest for our area. These downsloping winds in
addition to clear skies will aid increased temperatures, with
highs back in the triple digits.
&&
.LONG TERM...
(Monday night through next Saturday)
Issued at 211 PM CDT Sun Jul 23 2023
There are no significant chances to the previous forecast. An upper
ridge will continue to build over northern New Mexico and the
subsequent rising heights and south-southwesterly flow will allow
for consistent triple-digit high temperatures though much of the
week. Tuesday and Wednesday look to potentially reach heat advisory
criteria, with highs near 105. The GFS continues to show diurnally
driven convection moving through the area, however given the
strength of the ridge and how dry everything will be, thunderstorms
remain unlikely. A weak "cold" front will move through by the end of
the week, bringing some relief from the heat with temperatures
falling into the mid-to-upper 90s.
&&
.AVIATION...
(00Z TAFS)
Issued at 610 PM CDT Sun Jul 23 2023
VFR next 24 hours. High-based cu field remains far west of the
KLBB and KPVW terminals where a few showers exist, but these cells
will not move anywhere near the terminals. Thermal turbulence will
lead to rough rides tomorrow afternoon for GA and small aircraft
with mixing heights soaring to 14 kft MSL INVOF KLBB and KPVW.
Check density altitude.
Sincavage
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...12
LONG TERM....19
AVIATION...09
Area Forecast Discussion
National Weather Service Phoenix AZ
508 PM MST Sun Jul 23 2023
.UPDATE...00Z Aviation Discussion.
&&
.SYNOPSIS...
The Monsoon High will continue to remain unseasonably strong
through the middle of this week, allowing record hot temperatures
to continue. An Excessive Heat Warning has been extended through
Wednesday for much of Maricopa County including the Phoenix metro,
where the HeatRisk will remain at Major to Extreme levels. Rain
chances will increase across south-central AZ this afternoon and
this evening, including the lower deserts. Daily thunderstorm
chances will continue mainly for the higher terrain east of
Phoenix through much of next week.
&&
.DISCUSSION...
Satellite imagery reveals an MCV across SE California that has
brought clouds and somewhat cooler conditions along with scattered
light rain end even a few lightning strikes to the area.
Meanwhile, latest mesoanalysis places the center of the Monsoon
High near the Four Corners. The anticyclone combined with another
weak MCV across southwestern New Mexico is resulting in a 20 kt
ESE steering flow across central Arizona. Latest ACARS soundings
indicate that despite the positive mid-level height anomalies,
temperatures at 500 mb are quite low (approaching -8 deg C), which
is yielding 700-500 mb lapse rates above 8 deg C/km. At the
surface, temperatures are running a few degrees cooler than at
this time yesterday, while dewpoints are a few degrees higher.
Nevertheless, temperatures at Sky Harbor Airport will again flirt
with the daily record of 115 degrees, last set in 2018.
Latest mesoanalysis indicates considerable but decreasing
convective inhibition across the lower deserts, largely a result
of warming near 700 mb and sub-8g/kg mixing ratios just above the
surface. Initial convective initiation is likely to take place
across the higher terrain east of Phoenix where PWATs remain above
an inch. Latest runs of the U of A WRF suggest this activity will
weaken as it propagates westward out of the foothills and towards
the Valley. However, the outflow will provide additional low-
level moisture convergence early this evening, which will help
erode the residual CIN. This will subsequently promote rapid
development of cells across the lower deserts of Maricopa County,
possibly including the Phoenix area. NBM PoPs were again adjusted
downward, but still range from 30-50 percent from Maricopa County
eastward. With DCAPE exceeding 1500 J/kg, any storms that develop
will be capable of producing strong to severe wind gusts.
&&
.PREVIOUS DISCUSSION...
As we start off this week, high pressure aloft will continue to
migrate ewd over NM and far W TX. This will result in 500 mb flow
becoming more southerly over our forecast area. Unfortunately this
pattern is more unfavorable for thunderstorm activity across the
lower desert areas and thus rain chances will decrease to around 20
percent or less beginning Monday afternoon. The higher terrain north
and east of Phoenix and far southeastern AZ will see the better rain
chances around 30-50% through the middle of this week. The Excessive
Heat Warning will continue through Wednesday for most of
Maricopa County including the Phoenix Metro area where highs will
top out near record levels each day this week. Latest longer range
models are showing signs that the subtropical high will finally
begin to weaken by next weekend which would signal a potential end
to the extreme heat.
&&
.AVIATION...Updated at 2350Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
The main aviation concern this forecast period will be the
potential for outflow winds. However, there is decreasing
confidence that thunderstorms will reach the Phoenix metro area.
Latest guidance pushes the arrival timing to around 01-02Z with
easterly wind gusts peaking near 35 kts between 01-04Z. The only
remaining impact will be the potential for visibility reductions
due to blowing dust. Winds will diminish tonight and maintain a
southeasterly component overnight before west winds return
tomorrow afternoon. There is about a 30% chance of an outflow
boundary coming from the south tomorrow afternoon through evening.
Otherwise, FEW to SCT cloud bases near 12 kft will be common
throughout the period.
Southeast California/Southwest Arizona including KIPL and KBLH:
No aviation concerns are expected as mid/high clouds linger over
the region this forecast period. Winds will be primarily
southeasterly at KIPL and southerly at KBLH. There is some
indication (30-50% chance) that an outflow from mountain ranges
west of KIPL will occur tomorrow afternoon. However, confidence is
too low to include in the TAFs at this time.
&&
.FIRE WEATHER...
There will be a better chance of showers and thunderstorms across
south-central AZ this afternoon and evening. The main hazards with any
storm that develops will be potential for new ignitions due to
lightning and gusty, erratic winds. Wetting rains will also be
possible this afternoon mainly across southern Gila County. Well
above normal temperatures will continue through the middle of this
week despite the increased monsoonal moisture. Relative humidity
will fall to around 10-15 percent each afternoon with overnight
recoveries remaining mostly fair. Outside of any convection, winds
will continue to favor diurnal trends with upvalley winds in the
afternoon and evenings with shorter lived downvalley patterns in
the late night and morning hours.
&&
.CLIMATE...
Record High Temperatures:
PHOENIX YUMA EL CENTRO
July 23 115 (2018) 117 (2014) 118 (2018)
July 24 116 (2018) 118 (2018) 121 (2018)
July 25 116 (2018) 120 (1943) 119 (1943)
July 26 116 (1995) 118 (1995) 118 (1934)
Active Streaks:
PHOENIX
1. Consecutive days of high temperatures 110F or greater: longest
on record at 23 days
2. Consecutive days of high temperatures 115F or greater: tied longest
on record at 6 days
3. Consecutive days of low temperatures 90F or greater: longest on
record at 13 days
4. Consecutive days of zero precipitation: 6th longest on record at
122 days
YUMA
1. Consecutive days of low temperatures 85F or greater: 6th longest on
record at 12 days
July 2023 Notes:
PHOENIX
1. Current average temperature of 102.7F is on pace for the hottest month
on record (second hottest month was August of 2020 at 99.1F)
2. All-time warmest low temperature of 97F set on July 19th
3. Daily record high temperatures tied or broke the previous record
for eight days (July 13th, 14th, 15th, 17th, 18th, 19th, 20th, and 22nd)
YUMA
1. Daily record high temperatures tied or broke the previous record for one
day (July 19th)
EL CENTRO
1. Daily record high temperatures tied or broke the previous record for three
days (July 15th, 18th, and 20th)
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST Wednesday for AZZ534-
537>544-546-548>551-553>555-559.
Blowing Dust Advisory until 11 PM MST this evening for AZZ548-
550>555-559.
CA...None.
&&
$$
DISCUSSION...Hirsch
PREVIOUS DISCUSSION...Salerno
AVIATION...Leffel
FIRE WEATHER...Salerno
CLIMATE...Young