Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/08/23
Area Forecast Discussion
National Weather Service Amarillo TX
527 PM CDT Fri Jul 7 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Saturday night)
Issued at 141 PM CDT Fri Jul 7 2023
Summary: Strong to severe thunderstorms are expected later this
afternoon through this evening across the Panhandles. All severe
hazards are possible, including hail up to or exceeding 2" early on,
and potentially widespread damaging winds this evening with some
gusts up to 80 mph possible. Strong to severe thunderstorms may be
possible Saturday, though that is highly conditional upon sufficient
destabilization.
Details: The special 18z sounding shows the atmosphere is,
unsurprisingly, still capped. There is still a decent layer of low-
level moisture below an inversion associated with the beginning of a
stout EML. There is impressive low-level shear along with favorable
deep-layer shear for organized severe weather.
Continued destabilization is expected across the area, though dew
points are sticking around in the upper 60s to lower 70s.
As recent as the 17z HRRR and RAP runs continue to overestimate the
effects of mixing on the surface dew points. Observed dew points are
sticking to around 67 degrees while HRRR and RAP suggest it should
be 3-6 degrees lower. Therefore, expecting LCLs to be lower and
instability to be higher than the near-term models depict.
Thunderstorms are expected to develop in the western combined
Panhandles, likely along a surface wind convergence boundary, around
3-4 PM. There will be enough shear for thunderstorms to become
supercellular which may produce hail up to or exceeding 2" in
diameter. A tornado or two will also be possible, especially in the
north where stronger low-level shear is expected. Upscale growth
into an MCS is eventually expected. The large hail threat will lower
some in this stage but there will be an increased threat for
potentially widespread damaging winds, including gusts up to 80 mph.
A tornado or two will be possible in this stage as well. The MCS is
expected to leave the area late this evening.
There is a low chance for additional thunderstorm development later
this afternoon in the eastern Texas Panhandle where a boundary may
set up and be a focus for discrete thunderstorm development. Visible
satellite is showing the development of streaks of low-level clouds
around early this afternoon. If thunderstorm development does occur,
a supercell would be favored with all hazards possible including
hail up to or exceeding 2".
Saturday: The overall setup doesn`t change much. However, today`s
severe weather is expected to aggressively stabilize the atmosphere
such that it is very uncertain whether it will be able to
destabilize enough by Saturday evening. If it does, all severe
hazards would be possible again. But given the uncertainty in
sufficient destabilization, will opt to focus on today`s severe
weather potential and re-assess the situation in future forecast
packages.
Vanden Bosch
&&
.LONG TERM ...
(Sunday through next Thursday)
Issued at 141 PM CDT Fri Jul 7 2023
Additional chances for rain returns to the Panhandles, but it may
not be as widespread. While some areas may get additional
rainfall, others areas will begin to dry out with temperatures on
the rise.
As the center of the main H500 high pressure system slowly shifts
north into central New Mexico, additional areas of thunderstorms
are expected Sunday and Monday. Perturbations associated with
ridge rollers, along with any residual surface boundaries from
previous areas of convection and/or a stalled front will act as a
catalyst for additional diurnally driven convection. In
particular for Sunday and Sunday night, storms could be severe
with large hail and damaging wind gusts being the main threat.
High temperatures will be near to slightly below average,
especially in the northern Panhandles where areas north of the
stalled front will experience slightly below average
temperatures.
A small break in the precipitation chances should come mid week
as latest 07/12Z model and numerical data shows the eastern extent
of the main H500 high into the Panhandles. Large scale subsidence
aloft should minimize rain chances and warm temperatures up. High
temperatures Tues-Thur will range from mid 90s to 100-104. As
main H500 high shifts further back to the west, NW H500 flow
returns and so do our rain chances, favoring the northern
Panhandles.
Meccariello
&&
.AVIATION...
(00Z TAFS)
Issued at 520 PM CDT Fri Jul 7 2023
A line of strong to severe thunderstorms is currently working
through the combined OK/TX Panhandles from west to east. Even
after this line leaves the Panhandles by 03Z there will still be
scattered showers/tstorms that may impact the terminals through
12Z for KAMA and KGUY, 10Z for KDHT. Gusty winds possibly in
excess of 40 kts will be possible with the line of thunderstorms
that is now east of KDHT. Low clouds may move into the north
impacting KGUY towards 10Z. However, confidence is low at this
time and not in the TAF at this time. This will need to be
reassessed during the next TAF issuances.
36
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 65 87 65 85 / 40 10 40 10
Beaver OK 63 78 60 77 / 70 10 70 20
Boise City OK 60 77 59 78 / 50 10 60 10
Borger TX 65 85 65 86 / 50 10 50 10
Boys Ranch TX 65 88 66 88 / 30 10 30 0
Canyon TX 65 89 65 87 / 40 10 30 0
Clarendon TX 68 87 66 83 / 50 10 40 10
Dalhart TX 62 81 61 82 / 30 10 40 0
Guymon OK 62 77 60 77 / 40 10 70 10
Hereford TX 65 91 66 91 / 30 10 20 0
Lipscomb TX 63 79 60 78 / 70 10 70 30
Pampa TX 65 82 64 81 / 70 10 60 20
Shamrock TX 66 86 64 83 / 60 10 50 20
Wellington TX 68 90 66 86 / 50 10 40 20
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...52
LONG TERM....29
AVIATION...36
Area Forecast Discussion
National Weather Service La Crosse WI
1045 PM CDT Fri Jul 7 2023
.DISCUSSION...(This evening through Friday)
Issued at 230 PM CDT Fri Jul 7 2023
Key Messages:
- Increased shower chances south of I-90 through tonight and
with a few showers north of I-90 Saturday
- Periodic thunderstorm chances for much of next work week,
although confidence in timing and in any organized stronger
storms is lower.
Overview:
Surface high pressure has built into the area. Overnight lows
dropped into 40s to around 50 for most locations and even a few
upper 30s in our noted cold spots of Black River Falls (38) and Volk
field (30). With the clear skies, relatively moist ground and light
and variable winds, we did see river valley fog develop around 08Z.
BCK also dropped down with dense fog for a short time after 1030Z.
Most of the fog burned off by 14Z with high clouds on the increase
by that time. Water vapor satellite imagery, heights and lightning
showed the broad trough over central Canada into the Central Plains
with another open wave over the Pacific Northwest. Deeper mid and
upper level moisture were noted ahead of the trough from the Upper
Mississippi Valley into the Plains with clusters of storms over
parts of northern MN, southeast Nebraska and southwest Iowa, Kansas,
and Oklahoma into northern Texas late this morning. Through
Saturday, shortwave trough energy will swing through the Upper
Mississippi Valley and the Plains with shower activity spreading
into the forecast area.
Shower/Storm chances through Saturday:
An area of showers is pushing east across Iowa and southern Minnesota
and into Wisconsin with thunderstorms farther to the southwest.
Moisture transport is across southern Iowa, however there appears to
be enough mid and upper level support to bring some of the deeper
moisture northward per forecast soundings on the HRRR/RAP. The
greater frontogenetic signal is south of the forecast area. Although
the wave will be pushing into a drier airmass a few of the CAMs show
enough moistening where a few showers and possibly some embedded
thunder for parts of northeast Iowa should occur. The latest 07.12Z
deterministic GFS/EC and HRRR are a bit more aggressive with the
showers pushing across northeast Iowa. Although the operational
NAM has suffered with convective feedback, the 07.12Z NAM has these
trends as well. As a result of the latest radar trends and trends
in the operational short term models, have increased shower chances
south of I-90 through the evening. These trends may have to be
adjusted further. A cold front will move into the area Saturday
with steepening lapse rate and increasing instability. Convective
temperatures are in the mid to upper 70s. For now I have a few
showers north of I-90.
Sunday-Friday:
On the large scale, a strong upper level low will become established
near Hudson Bay while broad upper level ridging extends from the
Desert Southwest into the southern plains. In between, a belt of mid-
level westerlies will be found across the Upper MS Valley with model
guidance generally indicating several subtle, low predictability
shortwave troughs passing through the flow resulting in broad-
brushed rain chances through much of next week after a dry,
seasonable Sunday.
On Monday into Tuesday, a cold front will slide south across the
region, although some timing discrepancies persist. As a result,
precip chances remain only in the 20-50% range Monday
afternoon/night. The higher deep layer shear is expected to be post-
frontal on Monday. Thus, organized severe weather potential looks
low, although CSU GEFS-based probabilities show low (5%) chances for
severe weather Monday from southeast MN into northern WI and across
northeast IA and far southwest WI on Tuesday. Beyond Tuesday,
periodic showers/storms remain possible as shortwave troughs
continue to rotate around the southern periphery of the trough
across Canada, with the highest chances right now centered on
Wednesday.
For temps, Monday looks to be the warmest day of the week with highs
in the 80s to near 90 ahead of the front. Later in the week,
comfortable temps/humidity levels for mid-July are expected as
seasonable to slightly below average temps are favored within the
upper level west to northwest flow pattern.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1045 PM CDT Fri Jul 7 2023
VFR conditions should continue into Saturday. Mid level ceilings and
showers associated with passing short wave will continue to break up
or clear overnight with relatively light low level flow. Waining
convection upstream could also contribute some mid to high level
ceilings from time to time. Given scattered showers this evening,
light winds, and clearing, will have to watch for patchy fog
formation but at this time, not expected to impact TAF sites.
Even quieter on Saturday with possibility of some diurnal cumulus
with flow remaining weak.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...NONE.
IA...NONE.
&&
$$
DISCUSSION...Zapotocny/JM
AVIATION...Shea
Area Forecast Discussion
National Weather Service Boston/Norton MA
944 PM EDT Fri Jul 7 2023
.SYNOPSIS...
Could see a few showers or t-storms move into western MA/CT
this evening. Stratus and fog develops across the south coast
this evening and pushes northward tonight and burns off Sat AM.
Still warm and humid Saturday with afternoon showers and
t-storms. More active and unsettled for Sunday and Monday, with
several opportunities for showers and thunderstorms capable of
heavy downpours. Rain chances greater in central and western
parts of Southern New England Sunday, then shifting eastward
into most of Southern New England on Monday. Flooding may be
possible. Hit-or-miss showers and thunderstorms on Tuesday.
While Wednesday is finally a dry day, it will be hot and humid.
The dry weather pattern is brief, with rain chances increasing
through the end of the workweek.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
945 PM update...
A few weakening showers across northern MA will dissipate
leading to a dry night. Still about 1000 J/kg of MLCAPE across
western MA/CT and a few showers are moving east from eastern NY
with a lone t-storm over SE NY. However, the environment is
stabilizing and activity is weakening as it heads east.
Otherwise, stratus and fog along the immediate south coast will
expand back northward as the boundary layer cools a bit with
nighttime radiational cooling. Under light SW flow, the area
from about ORH to OWD probably serves as its northern limit. Fog
should also be primarily to the immediate south coast, and it
may again become locally dense. Lows mid 60s to low 70s still
seem on track.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/...
Highlights
* Stratus/fog burns off Sat AM, but may linger into early
afternoon across immediate south coast. Widely scattered
showers/storms especially across the interior Sat PM.
* Rinse and repeat as stratus/fog fills back Sat night into
early Sun from the south coast.
Cyclonic flow persists through this period. Will have a
shortwave over the central Great Lakes early on Sat lift into
the OH Valley by late in the day and eastern Great Lakes by
early Sun. The stalled out frontal boundary will be situated
just to the west of our region through this timeframe.
As has been the case over the past several days will see the AM
stratus/fog lift and burn off. Have once again leaned toward the
HREF and other short term guidance as it shows this trend quite
well. Think that there still could be low clouds lingering
across the Cape/Islands into the into the afternoon.
Main concern during this period is the return of more widespread
scattered showers and storms, especially Sat afternoon.
Expecting the heating of the higher terrain, localized sea
breezes and nearby stalled out front to provide the forcing
given we are a bit removed from the next shortwave lifting in.
Won`t have any issues with moisture as dew points will be
oppressive in the upper 60s to low 70s and PWATS of 1.5-1.75
inches. Should have instability values of roughly a few hundred
to 2000 J/kg of MLCAPE. May be difficult for storms to get
organized as we are lacking deep layer shear, which is
essentially nil to perhaps 20 kts within the 0-6 km layer. The
mid level lapse rates are meh around 5-6 degrees Celsius per km,
while low level lapse rates are around 7-9 degrees Celsius per
km and a fair amount of DCAPE. Think storms may be a pulsey in
nature, but pose a locally heavy rainfall/flood risk along with
the strong/damaging winds. The NCAR HRRR Neural Network 12Z
guidance indicating some low probs of winds AOA 50 kts across
the interior. Agree with WPC Day 2 excessive rainfall outlook
with the risk highest across the interior. Should see this
activity on the uptick Sat PM before it diminishes once again
during the evening.
Expecting it to remain hot and humid. High temperatures range
from the mid 70s to the upper 80s. The stratus/fog returns as it
lifts from the south coast Sat night into early Sun, though we
could see some showers/storms push in toward daybreak. Lows
bottom out in the mid 60s to low 70s.
&&
.LONG TERM /SUNDAY THROUGH FRIDAY/...
Highlights:
* Soggy Sunday and Monday, with bulk of rain and embedded t-storms
Sunday into central and western sections of SNE, then shifting
eastward Sunday night into Monday into most of SNE. Heavy rain
possible along with potential for flooding and rises on rivers and
streams. Remains warm and humid. Stay tuned!
* More hit-or-miss showers and storms Tue but coverage should be
less than Sun-Mon.
* Dry Wednesday but rather hot and humid with mid 90s heat indices.
* Another round of rains Thu and Fri, though somewhat more coverage
on Fri.
Details:
Sunday and Monday:
A broad mid-level trough will be positioned to our west over the
northern Appalachians/northern mid-Atlc states Sun and Mon. This
will interact with the humid and weakly-unstable air mass and a
light SE to S upslope flow component. While the specific placement
isn`t clear, models are also simulating an area of low pressure that
moves NE/NNE from the mid-Atlantic to somewhere thru SNE/northern
New England later Sunday night into Monday. There is a growing level
of confidence on an active Sunday and Monday, with the greatest risk
being slow moving heavy downpours and a related potential for
flooding of urban/poor drainage areas as well as rises on rivers and
creeks. This is also consistent with WPC`s Days 3 and 4 excessive
rain outlooks.
Given the above and that storm motions appear likely to become
parallel to the mean 700-500 mb flow, it creates a potential
training rainfall scenario with rain falling over the same areas.
Pending continued model consistency and after an assessment of
antecedent conditions from prior days` shower and storm activity,
it`s too early to consider this as yet but will need to give some
consideration to a potential flood watch for parts of or most of SNE
Sunday and/or Monday. Current thinking is that the risk would be
greater in the interior on Sunday, then moving and/or expanding
eastward into the urban areas in central and eastern SNE for Monday.
Utilized a blend of WPC and RFC`s forecast QPF for Sunday and then a
WPC-NBM blend for Monday to generate Sunday thru Monday storm total
rainfall ranging from up to an inch for eastern MA and RI, around 1-
2 inches for central MA and east-central sections of northern CT,
with 2 to 3 inches of rain for western MA and Hartford County in CT.
Confidence in the rain totals is rated as moderate, somewhat higher
on the spatial extent but lower on the magnitudes and the potential
for locally higher rain totals exists in more persistent downpours.
For Sunday, while eastern portions of SNE should see a relative
minimum in rain/thunder chances, the focus for several rounds of
showers and thunderstorms (PoP in the higher-Likely category) mainly
from ORH-IJD westward during the day on Sunday. This risk then
begins to shift eastward into Sunday night and Monday. While the
potential for severe weather is limited both days with rather
abundant cloud cover tempering instability to around 1000 J/kg,
Monday could have both a hydro component but also some isolated
severe weather as the approaching low pres moves northward, given
increasing mid level flow, low LCLs and the potential for low-level
winds to become somewhat more backed (e.g. southeast/easterly).
Highs should be around or somewhat lower than normal under abundant
cloud cover and somewhat warmer than normal on the lows. It will
nonetheless be quite humid through Monday.
Tuesday:
The active soggy pattern will continue into Tue, as the northern mid-
Atlc trough migrates over and thru SNE. However shower and t-storm
coverage should be a little more hit-or-miss than Sunday and Monday.
Highs should also be a little warmer with lower to mid 80s and lows
in the mid 60s.
Wednesday through Friday:
We do get into a drier weather pattern for at least Wednesday,
although temperatures will rise back to above normal, summerlike
levels in the mid 80s to low 90s and elevated humidity.
For late Thurs and Fri, continued broad cyclonic flow over the
central US/central Canada will lead to another shortwave trough to
our west with a similar pattern to that for Sunday and Monday.
Uncertainty on which day may offer better chances but NBM`s higher
PoP (around 40%) on Fri seems most reasonable with more isolated to
scattered coverage on Thu.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Forecast Confidence Levels:
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update:
Tonight: High confidence.
ISO/widely SCT SHRA/TS should dissipate by 02z mainly affecting
BAF. Otherwise, VFR at least for a few hrs; IFR-LIFR
fog/stratus now lurking over the southern waters to expand
northward between 01-05z to PVD, the Cape airports and ACK,
while expanding slightly northward into ORH/BDL after 06z. Think
BOS should stay out of the stratus layer given light SSW winds
but could be close/mainly at OWD. Areas of dense fog confined
to the immediate south coast. Light S/SSW winds.
Saturday...Moderate confidence.
Will have any stratus/fog lift and burn off by roughly 12-14Z
for most locations. The only exception is across the
Cape/Islands where it may not lift until closer to 18Z, though a
this point think ACK will have a similar trend to today.
Scattered showers/t-storms develop across the interior around
16-18Z and persist into the evening. Winds out of the SE to the
E at 5-10 kts.
Saturday Night...Moderate confidence.
Should see any lingering shower/storms tapering off during the
evening. Generally expecting VFR, but could have some MVFR to
perhaps IFR conditions across the CT River Valley with fog
development. Could see showers/storms uptick again toward
daybreak out west. Light S to SE winds.
BOS Terminal...High confidence in TAF. S winds should ease in
speed through tonight. Anticipating VFR tonight. MVFR-IFR
stratus may be nearby overnight, but think the northern limit of
stratus is around OWD. Sea breeze around 14z Sat.
BDL Terminal...High confidence in TAF. Mainly VFR, but with
MVFR-IFR stratus pushing in 05-07Z and lifting roughly 12-14Z.
Potential for SHRA/TS after 16z Sat, which could be strong.
Outlook /Sunday through Wednesday/...
Sunday: Mainly VFR, with local MVFR possible. Chance SHRA,
slight chance TSRA.
Sunday Night: MVFR/IFR conditions possible. SHRA likely, chance
TSRA.
Monday: Mainly MVFR, with local IFR possible. SHRA likely,
chance TSRA.
Monday Night: Mainly VFR, with local IFR possible. Chance SHRA,
isolated TSRA.
Tuesday: VFR. Chance SHRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight through Saturday Night...High confidence.
Boating conditions remain tranquil through the forecast with
light winds and calm seas. As has been the case the past several
days the main impact will be areas of poor visibility overnight
into the morning as fog and stratus redevelop. The risk is
especially high across the southern coastal waters, where fog
could be dense at times.
Outlook /Sunday through Wednesday/...
Sunday: Winds less than 25 kt. Slight chance of rain showers.
Sunday Night through Monday: Winds less than 25 kt. Chance of
rain showers, slight chance of thunderstorms.
Monday Night: Winds less than 25 kt. Chance of rain showers,
isolated thunderstorms.
Tuesday: Winds less than 25 kt. Chance of rain showers.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...Loconto/BL
NEAR TERM...KJC/BL
SHORT TERM...BL
LONG TERM...Loconto
AVIATION...Loconto/BL
MARINE...Loconto/BL
Area Forecast Discussion
National Weather Service Cheyenne WY
521 PM MDT Fri Jul 7 2023
.SHORT TERM...(This evening through Sunday night)
Issued at 240 PM MDT Fri Jul 7 2023
Concerns with this forecast package deal with severe thunderstorm
potential this afternoon through Saturday.
Currently...1018mb surface high located across north central
Wyoming north of Converse County with a surface boundary across
northwestern Colorado this afternoon. Convection has been
percolating north of this front along the Wyoming/Colorado state
line. Getting a few lightning strikes over the south Laramie
Range...but everything else has not been producing any lightning
at this time.
Not too concerned with severe thunderstorms today...though SPC has
us in a Marginal Risk area. SPC mesoanalysis showing SBCAPE
around 1000 J/KG at the most extreme from RAP guidance. But given
how storms have been performing the past several days...can not
rule out a few severe storms.
Saturday should be more interesting as boundary over northwest
Colorado begins to move northeast into the southeast Wyoming
plains. Upper disturbance tracks across southern Wyoming which
aids in the front getting northeast. 95kt nw-se 250mb jet cuts
across Carbon County with our eastern zones on the north and east
side of this jet. Eastern Wyoming plains SBCAPE up near 1200-1800
J/KG with ample 0-6km shear. Panhandle may be a bit more capped
Saturday with not a whole lot of instability. Looks like SPCs
SLight Risk reflects that...keeping the Slight Risk area in
southeast Wyoming. PWATs quite high Saturday afternoon as
well...with all forecast sounding east of the Laramie Range
forecast over an inch of PWAT. So heavy rain/possible flash
flooding could be a concern tomorrow as well. WPC does outline a
Marginal Risk for excessive rainfall for the southeast WYoming
plains into northeast Wyoming for tomorrow afternoon.
Rising heights for Sunday as southwestern ridge begins to slowly
move into western Wyoming. 700mb temperatures climb to +12 to
+15C...up from +8 to +12C Saturday. Have a few thunderstorms
east of the Laramie Range along the I-80 corridor from Cheyenne to
Sidney Sunday afternoon.
Looks like ridge axis will be over the CWA Monday with dry
conditions and very warm temperatures Monday afternoon.
.LONG TERM...(Monday through Friday)
Issued at 240 PM MDT Fri Jul 7 2023
Minimal changes made to the long term forecast from the previous
shift. Long range models remain in close agreement that next week
will be drier and warmer for the most part with isolated
thunderstorm chances. GFS and ECMWF ensemble means continue to show
the ridge across the southwest CONUS extending into southeast
Wyoming and the Nebraska panhandle, injecting a much drier, more
stable airmass, limiting thunderstorm concerns Monday. Tuesday the
ridge is flattened out as a shortwave skims the Nebraska panhandle,
providing isolated to scattered thunderstorm chances in the eastern
panhandle and the warmest temperatures expected next week. High
temperatures in the upper 80s to 90s across southeast Wyoming and
the Nebraska panhandle. This is well-above-average for southeast
Wyoming, but only 2 to 5 degrees above-average for the Nebraska
panhandle. Wednesday and Thursday is a return to zonal flow with
isolated thunderstorm chances, mainly in the Nebraska panhandle, and
temperatures a few degrees cooler than Tuesday. This forecast is a
welcome change from the widespread severe weather we have been
experiencing! However, we want this precipitation to continue to
limit fire weather concerns in the future. All in all, as long as
the pattern holds we will finally experience some summer next week!
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 514 PM MDT Fri Jul 7 2023
VFR conditions are expected to continue through the majority of
the TAF period, with some chances for IFR tomorrow morning.
Current radar imagery has some showers and thunderstorms along the
CO/WY border and moving eastward across just south of the Nebraska
Panhandle. Some uncertainty in the near term forecast with HiRes
model guidance indicating some cells developing across southeast
Wyoming later tonight and pushing eastward into the Panhandle
through the late night hours. As a result, kept VCTS and VCSH in
the TAFs to account for these model solutions. In addition,
confidence is increasing for IFR conditions across KCYS where
plenty of moisture at the surface and upslope flow will aid in low
stratus and fog to develop. Will need to reevaluate the remaining
terminals in southeast Wyoming to see if those conditions will be
met at KRWL and KLAR.
&&
.FIRE WEATHER...
Issued at 240 PM MDT Fri Jul 7 2023
High pressure over central Wyoming this afternoon will bring east
to northeast winds and cooler temperatures to most area today and
Saturday. A stalled out surface front lays across central and
western Colorado this afternoon. Looks like most thunderstorms
today will be confined near the I-80 Corridor from Cheyenne to
Rawlins. Showers and storms may continue this evening across
southern Albany and maybe northern Carbon County as another
disturbance moves through this evening. Better chances for wetting
rains Saturday afternoon and evening along and east of the
Laramie Range. A warmer and drier pattern taking shape for Sunday
on into next week as high pressure builds over Wyoming from the
southwest. Drier air currently over Utah and northern Arizona
expected to move into the area that could result in daily critical
afternoon humidity with poor overnight recoveries.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...GCC
LONG TERM...LK
AVIATION...MRD
FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
National Weather Service Kansas City/Pleasant Hill MO
642 PM CDT Fri Jul 7 2023
.Discussion...
Issued at 300 PM CDT FRI JUL 7 2023
Key Messages:
-Scattered showers and thunderstorms are expected this evening. A
couple strong storms are possible with the potential for brief heavy
downpours, lightning, and small hail - especially south of I- 70.
-Heat begins to build next week. High temperatures in the 90s and
heat indicies near 100 are possible on Tuesday and Wednesday.
Discussion:
The remnants of the morning MCS has moved into northeast Missouri
this afternoon. The outflow has made it into the northern KC metro
as winds at KMCI have turned to the northeast as of the 2 PM
observation. This boundary could be an area to watch for
convective initiation late this afternoon south of I-70. There are
weak radar returns showing up along the boundary early this
afternoon. South of this boundary (south of I-70), surface based
CAPE has climbed between 1000-2000 J/KG with higher PWATs and
dewpoints. This area is also on the fringe of the higher midlevel
wind field. There is enough speed shear to support a couple strong
storms this evening. Widespread severe storms are not expected. A
shortwave will push across the area this evening and tonight and
is expected to trigger scattered showers and thunderstorms. Early
morning runs of the HRRR as well as various other hi-res guidance
were a little more robust with convection both in terms of
coverage and intensity across the forecast area this evening. The
latest runs have backed off. Thunderstorms will continue to be
more numerous across east central and and portions of southern
Missouri, as well as across southern Kansas. These areas have more
instability and 925-850mb moisture transport will continue to be
focused across southern Kansas.
Early morning cloud cover should eventually give way to at least
partial clearing by Saturday afternoon. The weekend is shaping up
to be quite pleasant with a surface high settling in across the
area. The weather will be dry with temperatures in the lower 80s
for highs and dewpoints near 60.
By early next week, the jet stream carves out a northerly path
across the CONUS from the Pacific Northwest to the Great Lakes.
Building heights are expected from the Plains to the Mississippi
Valley. Southerly flow will usher in much warmer temperatures on
Tuesday and Wednesday with 850mb GEFS temperature anomalies of
approximately 5-10 C. This is certainly not a pattern indicative of
record temperatures, but we should expect temperatures back in
the 90s with heat indicies potentially eclipsing 100 F. There is
still some uncertainty with precipitation during this time,
especially once the ridge breaks down on Thursday and Friday.
There should be some showers and thunderstorms during that time,
but the details are unclear at this point. Regardless, it doesn`t
appear to be a long term heat event locally. The hot and dry
pattern will remain to our south across the Southern Plains and
southwest US.
&&
.Aviation...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 638 PM CDT FRI JUL 7 2023
Broken line of showers with embedded thunderstorms will work south
this evening along a cold front moving through the region. Behind,
the front, MVFR stratus is expected to build in, and continue
through the morning hours on Saturday. Could see ceilings briefly
fall into the IFR range around sunrise, but confidence is not high
enough to include in the forecast at this point. Also the
potential for some light fog overnight, best chances at KSTJ.
Ceilings are expected to gradually improve through the morning
hours Saturday, returning to VFR Saturday afternoon.
&&
.EAX WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
MO...NONE.
&&
$$
Discussion...CLF
Aviation...BT
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
627 PM CDT Fri Jul 7 2023
...Aviation Update...
.DISCUSSION...(This evening through Friday)
Issued at 355 PM CDT Fri Jul 7 2023
Key Messages:
* Isolated to scattered showers/storms exit SE portions of the
area this evening, leaving mainly dry and quite comfortable
conditions for the rest of the weekend.
* Temperatures warm back up closer to normal early next week.
* Persistent NW upper flow leads to return of active pattern and
multiple chances/rounds for storms next week, some of which
could come in the form of strong-severe nocturnal complexes.
Forecast Details:
Shortwave disturbance seen on WV imagery moving from the Dakotas
into Minnesota is forcing a cold front through the area from N to
S this aftn. Plentiful low level moisture (PWATs around 1.5"),
modest deep layer moisture flux convergence, and weak capping is
leading to iso-scat tstms along and ahead of this cold front,
which currently lies from OLU to HSI to HLC. SPC meso page shows
decent MLCAPE of 1000-2000 J/kg (highest W of Hwy 281), and latest
VAD confirms strong deep layer shear in place owing to strong
veering from Srly sfc winds to 50kt+ WNW flow at H5. This
CAPE/shear parameter space suggests a non-zero risk for a few
severe storms ahead of the front, but so far activity has really
struggled to maintain deep cores and organization. This is likely
due to substantial subsidence behind this morning`s departing
shortwave that produced a semi-organized band of effective rain-
producing convection that gave areas N of I-80 burst of mod to hvy
rain. Hwy 92 corridor was a particular benefactor of this system
in which widespread 1-3" occurred. The ongoing subsidence appears
to be keeping current convection in check, and with fairly high
freezing levels and no significant shortwave nearby/upstream,
seems unlikely there will be an appreciable incr to
intensity/organization through the eve hrs. Area remains in an SPC
Day 1 Marginal risk, but think main threats are sub-severe
hail/gusty winds and torrential downpours. HRRR has been
consistent with this activity weakening quickly around sunset.
Not sure what to do with fog potential tonight due to conflicting
signals and competing factors. On one hand, looks like temps will
cool nicely back into the 50s with help of some clearing this eve,
and today`s rainfall should keep some moisture in the BL, esp. N
zones. However, the N/NE winds don`t completely decouple and may
result in some dry air advection...and lingering low level
moisture may manifest as stratus instead of fog. Have added some
patchy fog wording as I could envision shallow ground fog in
protected valleys, esp. on edges of any stratus. This should favor
N/NW/W zones the most.
The weekend as a whole is looking awfully nice by July standards
as humidity will be held in check, temperatures will be pleasant
in mid 70s to mid 80s amidst decent sunshine and fairly lgt winds.
The weekend will have cool mornings for those who don`t like the
heat, but also some warm afternoons factoring in the sunshine and
lgt winds. Get out and enjoy it if you can!
The pattern turns warmer early next week as upper heights rise in
response to building ridge over the S High Plains and Desert SW.
This will be short-lived, however, as an anomalously strong trough
(-2 to -3 std dev) drops southward through central Canada. The
impact to local pattern will be seasonably fast NWrly mid to upper
level flow and steady stream of shortwave troughs that interact
with oscillating warm sector and steep low/mid level lapse rates.
Conceptually speaking, this type of weather pattern tends to be
favorable for daily rounds of convection, and more specifically,
nightly MCSs that roll off the high plains in the NW to SE upper
flow, fed by nightly low level jets. Deterministic EC and ensemble
has shown some consistency in this type of pattern and both show a
sizable swath of above-normal pcpn right where one would expect
in the Central Plains, consistent with this conceptual pattern
idea. NBM hasn`t gone crazy on PoPs just yet, likely owing to
differences in track/timing and ridge/trough magnitude, but
appears Mon eve/night, Tue eve/night and Thu eve/night have best
potential for organized MCSs. This active flow will likely keep
temps in check in the 80s to near 90F, but this will depend on
timing and effects of outflow.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Sunday)
Issued at 623 PM CDT Fri Jul 7 2023
Winds will mostly be out of the north with some variability. Low
ceilings are expected to develop around 06z and continue through
most of the morning hours. Fog is possible tonight and early
Saturday morning.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...NONE.
&&
$$
DISCUSSION...Thies
AVIATION...Schuldt
Area Forecast Discussion
National Weather Service Goodland KS
900 PM MDT Fri Jul 7 2023
.SHORT TERM...(This evening through Sunday)
Issued at 308 PM MDT Fri Jul 7 2023
This afternoon skies are gradually clearing over the Tri-State
area. With the broad clouds exiting, a cumulus field is beginning
to show over the area as CAPE values increase and the cap slowly
degrades over Northeast Colorado. Through most of the afternoon
the area should remain dry as the cloud cover decreases. With
temperatures warming into the 70s to lower 80s, instability is
expected to increase over the Tri-State area while the higher mid-
level lapse rates move north over the area. There hasn`t been
much change in the SPC outlook for today. Latest guidance has
storms forming off the Front Range and Palmer Divide over the next
2-4 hours, moving east to east-southeast towards our area. Most
of the activity for this evening is expected to occur mainly along
and south of I-70, with potential for the stronger storms to
occur more in the Pueblo and Dodge forecast areas. Current
thinking is that these storms will be similar in mode and path to
last night, impacting those along and south of US-40 mainly. All
hazards are possible again today with large hail up to 2 inches in
diameter, up to 75 mph winds, and heavy rainfall. A tornado or
two also can`t be ruled out. Storms are expected to taper off
between midnight and sunrise tomorrow morning, with majority of
the severe potential ending around midnight. Overnight lows will
be in the 50s to lower 60s tonight.
Tomorrow, the upper ridge is expected to amplify over the Western
CONUS while the upper trough cross the Mississippi River Basin.
Shortwave disturbances are expected to move along the northwest flow
over the area on Saturday bringing more chances for storms during
the afternoon to overnight hours. All hazards will once again be
possible, with the main area of concern along and south of a Flagler
to Cheyenne Wells to Leoti line. Temperatures are expected to be in
the 70s for highs and in the mid to upper 50s overnight tomorrow.
Sunday is a bit quieter with lower chances for convection. The upper
ridge is expected to move further over the area while a surface high
moves over Eastern Kansas. Shortwave disturbances are expected to
help develop/strengthen a lee trough later in the day. As the
disturbances move over, a few showers and storms may be triggered.
The main area that could impact is our northern counties, especially
Yuma County. Confidence is low at this time for convection to
develop, but it can`t be completely ruled out. Temperatures look to
warm a bit more on Sunday with highs in the mid 70s to lower 80s.
Overnight lows will be in the upper 50s to lower 60s.
.LONG TERM...(Monday through Friday)
Issued at 145 PM MDT Fri Jul 7 2023
Ridge centered over the southern Rockies will be the dominant
upper feature during the long term period. High temperatures will
range from the upper 80s to lower 90s, with Tuesday looking like
the warmest day when temperatures may reach the middle 90s. Weak
disturbances moving over the top of the ridge will provide daily
chances of mainly afternoon and evening thunderstorms. Chances
should be more widely scattered early in the week with proximity
to the ridge, but increase towards the end of the week as the
ridge shifts further west and upper flow becomes more northwest.
Hard to rule out at least some risk of severe storms each day with
deep layer shear of at least 30 kts, increasing to 50 kts by the
end of the week. There will also be a front involved by the end of
the week which could further enhance severe risk. Given daily
rounds of showers and storms, the marginal to slight risk of
excessive rainfall is also likely to continue.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 900 PM MDT Fri Jul 7 2023
KGLD...VFR conditions are expected through 10z with winds from
the northeast to east at speeds under 10kts. From 11z-19z, sub
VFR conditions are expected in stratus and possibly some fog which
would reduce visibilities, potentially significantly. Latest HRRR
run has stratus lingering through the afternoon so some
adjustments may be needed. Winds remain from the east up to 10kts.
After 20z, VFR conditions are currently forecast to return with
winds continuing from the east up to 11kts. Regarding
precipitation chances, cant rule out some showers/possible
thunderstorms in the 16z-02z timeframe. Confidence is pretty low
as some models keep us dry due to the stratus preventing any
instability from developing. The better chance for precipitation
appears to be after about 03z where -TSRA has been included in the
forecast.
KMCK...VFR conditions are expected from taf issuance through 10z
with a light northeast wind. From 11z-14z, sub VFR cigs are
expected in stratus and a light and variable wind. After 15z, VFR
conditions return with winds remaining from the east up to 10kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...KMK
LONG TERM...024
AVIATION...99
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
845 PM CDT Fri Jul 7 2023
.SYNOPSIS...
Issued at 844 PM CDT Fri Jul 7 2023
After a few evening showers mainly along and west of the I-55
corridor, scattered showers and thunderstorms will become more
numerous across all of central Illinois overnight into Saturday. A
few of the storms could become strong along and south of a Danville
to Taylorville line Saturday afternoon. After that, a return to
cool and dry weather is expected for Sunday.
&&
.UPDATE...
Issued at 844 PM CDT Fri Jul 7 2023
No major changes to the forecast over the next 12 hours, still
expecting scattered showers and thunderstorms to increase in
coverage after midnight as a shortwave approaches from the west and
LLJ forcing ramps up. The regional radar mosaic already shows
scattered convection blossoming/tracking east across southern IA,
with some cells as far east as the MS River. As convection increases
across the CWA overnight, CAMs do suggest a potential for localized
areas of over 1" of rainfall, especially in the vicinity of the I-74
corridor, where showers/storms develop and track along the same east-
west oriented zone.
Regarding the marginal risk for severe storms across eastern IL on
Saturday, the potential hinges on the timing of the cold front.
Today`s 18z guidance trended faster (further southeast) with that
front, showing little to no convection across eastern IL tomorrow
afternoon. While the full 00z model suite isn`t in yet, the latest
(00z) HRRR shows a similar evolution to 18z guidance. The severe
weather potential for our CWA on Saturday afternoon certainly
seems to be trending lower. Made some reductions to PoPs Saturday
PM to account for these trends.
Erwin
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 313 PM CDT Fri Jul 7 2023
The remnants of an MCS that formed over the High Plains late last
night continues to track toward the Mississippi River. While the
airmass further east across central Illinois is dry/subsident
beneath prevailing high pressure, radar loops suggest showers will
spill into the Illinois River Valley over the next 2-3 hours. Have
therefore increased late afternoon PoPs to likely west of the
Illinois River. The showers will continue to diminish as they
push further eastward, but think at least scattered showers will
reach the I-55 corridor early this evening. After the initial band
of showers fades away, a lull in precip coverage will occur until
the nocturnal low-level jet energizes the environment ahead of an
approaching short-wave trough currently over northwest Iowa. All
CAMs suggest scattered convection after midnight...with the
greatest areal coverage focused immediately ahead of the wave
across north-central Illinois. Have therefore carried high chance
PoPs across much of the KILX CWA overnight...with likely
along/north of a Galesburg to Bloomington line. Instability will
remain meager with HREF ensemble mean MUCAPEs peaking at just
500-1000J/kg. This will be sufficient for thunder, but too paltry
for any severe weather risk.
Morning showers and thunderstorms will wane and/or track eastward
into Indiana toward midday Saturday...with attention then turning
to potential convective re-development along an advancing cold
front during the afternoon. The pre-frontal environment south of
the I-72 corridor will become modestly unstable/sheared with HREF
ensemble mean SBCAPEs increasing to 1500-2000J/kg and 0-6km bulk
shear values of 20-30kt. 12z 3km NAM and 18z HRRR both show
development mainly south of the KILX CWA: however, would not be
surprised to see widely scattered strong thunderstorm cells
capable of marginally severe wind gusts/hail along/south of a
Danville to Taylorville line from mid-afternoon through early
evening.
Barnes
.LONG TERM... (Sunday through Next Friday)
Issued at 313 PM CDT Fri Jul 7 2023
Once the front passes, a period of cooler/drier weather will be on
tap for Saturday night through Monday night. After that, a
second cold front will drop southward out of the Upper Midwest by
the middle of next week. There is still some uncertainty as to how
quickly the front will arrive: however, 12z Jul 7 models have come
into better agreement focusing FROPA late Wednesday. As a result,
have confined PoPs to the north and kept them in the slight chance
category through Tuesday before raising to likely by Wednesday
night as the front and a supporting upper wave arrive. Rain
chances will linger into Thursday and Friday as well, as the
frontal boundary becomes nearly stationary in the vicinity.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 636 PM CDT Fri Jul 7 2023
* A weakening line of showers is progressing east and will move
through KSPI/KBMI near the start of the period. No lightning
activity has been observed with these showers in the last hour,
and the gradual weakening trend is expected to continue.
* Between 02-06z this evening, the terminals should be dry with
VFR conditions. After 06z, scattered showers/storms overspread
the area from west to east, continuing through about 14- 17z in
the morning. Thunder chances are highest between 06-12z.
* Guidance suggests low MVFR or IFR ceilings are likely between
11- 17z Saturday morning. The NBM showed a 40-50% chance of IFR
ceilings during that period, so did include a few hours of IFR
at most sites. MVFR ceilings linger into Saturday afternoon
before lifting to VFR late in the period.
Erwin
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Indianapolis IN
942 PM EDT Fri Jul 7 2023
.Forecast Update...
Issued at 942 PM EDT Fri Jul 7 2023
High level moisture plume and associated cirrus and mid clouds are
increasing across the area this evening, and will continue to do so
overnight. The combination of limited radiative conditions as a
result, and weak warm advection should keep temperatures a few
degrees warmer than previous nights. Model blend is acceptable in
this pattern for temperatures without modification.
As a deeper surge of moisture on mean southwesterly low-mid
tropospheric flow arrives, showers and isolated thunderstorms will
increase later tonight and persist through morning. This activity
may be most concentrated with the leading edge of more pronounced
low-level warm/moist advection tied to a lead shortwave trough
embedded within the broader trough.
Later in the day, diurnal surface-based convection should be
confined to near and south of weakly baroclinic front and associated
low-level convergence. Models are not completely aligned on its
placement. Some are further south seemingly influenced to a more
significant degree by amplified lower latitude shortwave trough/PV
anomaly over West Kentucky. Others seem to have a broad surface low
at higher latitudes perhaps forced primarily by the broader trough.
In the former case, shallower mixing depths and lower theta-e post-
frontal environment with uniform northerly flow should preclude
convective development for at least the northwest half to two-thirds
of central Indiana during the afternoon. The latter case would lead
to a more north placement of frontal convergence and greater
buoyancy with broader spatial coverage of convection across central
Indiana. We will re-evaluate tonight and provide updated
probabilities.
The overall parameter space tomorrow afternoon will be characterized
by moderate instability and weak deep layer shear. Loosely organized
multicells upon collapse may produce strong wind gusts. The
thermodynamic environment may be marginally supportive of severe
wind gusts with the most intense convective cores, but lightning is
expected to be the primary hazard.
&&
.Short Term...(This evening through Saturday)
Issued at 300 PM EDT Fri Jul 7 2023
- Partly Cloudy this evening, increasing clouds overnight.
- Rain showers likely on Saturday.
Surface analysis early this afternoon shows a disorganized area of
high pressure in place over WI and the western Great Lakes. This
high was providing dry easterly flow to central Indiana. GOES16
shows just a few CU across Central Indiana. Farther west, an upper
trough was found over the eastern Dakotas and eastern NB. This
feature was spreading clouds and rain across western IA and will be
our main weather player on Saturday. Dew points across the area were
still moist, in the 60s.
Tonight...
High pressure to the north of Central Indiana will
continue to dominate our weather this evening, resulting in dry
weather and partly cloudy skies. Forecast soundings remain dry this
evening, however things begin to change overnight. Models show the
arrival of a short wave from the plains states pushing toward
Central Indiana. This wave was embedded with broad cyclonic flow in
place aloft that stretched across much of central Canada and the
Great Lakes. This wave is expected to result in a deepening of the
cyclonic flow tonight, extending it farther south into the Ohio
Valley. Forecast sounding and time heights begin to trend toward
saturation overnight, with a saturated column arriving near 10-12Z
within the Wabash Valley. Thus will continue a dry forecast this
evening, but increasing clouds overnight as the surface high departs
and the short wave arrives. Chance pops will be needed late at
western points in the forecast area. Given the increasing clouds
overnight as a slightly warmer air mass in the area today, lows will
be warmer than yesterday, in the middle and upper 60s.
Saturday...
Rain looks likely on Saturday. Models show cyclonic flow in place
aloft throughout the day. Furthermore, a pair of short waves, one in
the morning and another in the afternoon, embedded within the flow
appear poised to push across central Indiana through the day. This
should provide adequate forcing for showers and thunderstorms.
Forecast soundings show a saturated column by 18Z with pwats over
1.80 inches. HRRR shows showers pushing across Central Indiana
through much of the day. Given the expected clouds and scattered
showers in the area, daytime heating should be limited somewhat.
This in turn will limit instability and thunderstorm chances.
Thunderstorms cannot be ruled out, but should be more isolated in
coverage compared to the expected showers. Thus given the forcing
and favorable moisture conditions, will use at least high likely
pops across much of the forecast area on Saturday. Given the rain in
the area, highs will reach upper 70s to near 80.
&&
.Long Term...(Saturday night through Friday)
Issued at 300 PM EDT Fri Jul 7 2023
The long term will feature an unseasonably potent upper trough over
interior/central Canada while seasonably hot weather continues over
the Four Corners and southern Plains where a somewhat suppressed
subtropical ridge will generally remain. Indiana will be sandwiched
between these features which will promote occasional to frequent
opportunities for showers and thunderstorms, with overall moderate
humidity and seasonably warm conditions...while weather for any
particular day is influenced by the position of the northern trough
and any up/downstream lobing wave or dragging boundary.
Saturday Night through Tuesday...
A marginal threat of strong/severe storms will continue Saturday
night with CAMs noting the potential for at least a couple further
rounds for multi-cellular activity crossing the region in a west to
east direction ahead of an approaching front. Latest guidance notes
the set-up through this nocturnal period to be conditional with
modest amounts of both overall and low-level shear, yet along with
probably just enough instability to allow a few stronger cells, if
not maintain marginal severe winds arriving from Illinois. Focus of
concern so far would be more across southern/eastern counties where
instability should be greater. Rather weak but organized frontal
boundary should cross the region towards Sunday morning which would
align any lingering convection into a more linear fashion after
midnight, while likely ending any severe threat from west to east.
Additional rainfall Saturday night should be light for most
locations, although potential for moderate to locally heavy rainfall
over southeast zones exists with up to 1.80 inches of precipitable
water in the column ahead of the front. Any flash flood potential
would be greater over area that received appreciable rains during
the day Saturday, with the overall threat limited per the midsummer
season and the vast majority of the region at a 3-hour Flash Flood
Threshold of 2.75-3.75 inches.
Early next week should have the only extended dry period of the long
term with a broad yet low-amplitude southern extent of the upper
trough gradually crossing the Midwest while slowly-weakening surface
high pressure glides from the central Plains to the Ohio Valley.
Convective chances will linger into Sunday amid the slowly passing
frontal zone with a similar set-up to that seen in recent days...yet
low confidence in any strong/severe cells per any near-zero shear
and instability confined to far southeastern counties. Temperatures
are expected to be lowest for Sunday/Sunday Night when readings will
range around 80/60...with mid to upper 80s returning to most places
by Tuesday on moderate southwesterly breezes.
Wednesday through Friday...
A more summery pattern will resume for the second half of the week,
at least in the return of higher humidity, as southwesterly to
westerly surface flow helps to bring the northeastern extent of the
southern ridge towards the Midwest. Ensembles are suggesting the
northern weakness pattern should shift slightly to broader and
farther south with a couple short waves progged to cross the
northern Plains and Great Lakes. This combo will bring at least
widely scattered showers/TRW chances to northern zones around the
Wednesday timeframe. Any MCS threat would be most likely near the
Middle Mississippi Valley around the Thursday timeframe...with
decaying cells sliding to the east-southeast and potentially into
the CWA. The pattern would also promote frontal boundaries
approaching and perhaps dragging across the Midwest which would
bring at least high-chance POPs if not several convective threats.
Although so far no higher confidence in organized or widespread
severe episodes. Temperatures should be near to slightly above
normal with highs in the 80s and lows in the 60s to near 70F.
&&
.Aviation...(00Z TAF Issuance)
Issued at 729 PM EDT Fri Jul 7 2023
Impacts:
* Scattered showers and isolated TSRA possible after 12Z
Discussion:
A shortwave trough will move toward Indiana tonight and across the
state on Saturday. High Clouds are expected to increase overnight as
the trough approaches overnight, but any ceilings will remain VFR.
Lower ceilings can be expected during the day with some at least
brief MVFR possible. Showers and isolated thunderstorms can be
expected from early morning lasting into the afternoon.
&&
.IND WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Update...BRB
Short Term...Puma
Long Term...AGM
Aviation...BRB
Area Forecast Discussion
National Weather Service Northern Indiana
801 PM EDT Fri Jul 7 2023
.SYNOPSIS...
Issued at 747 PM EDT Fri Jul 7 2023
Dry conditions are expected through late tonight into Saturday
evening, when we have chances for showers and thunderstorms. A few
storms may be strong to severe, with damaging wind, locally heavy
rain, and hail all possible threats. Low temperatures tonight
will be in the 60s. Highs Saturday will be in the 70s under cloudy
skies.
&&
.SHORT TERM...(This Evening through Saturday)
Issued at 300 PM EDT Fri Jul 7 2023
A broad trough across northern portions of the United States with
shortwaves in the flow defines our weather in the short term. Subtle
high pressure and residual dry air in the form of upper 50s to low
60s dew points keeps the area dry and mostly devoid of showers this
afternoon. As such, expect dew points to drop back into the low to
mid 60s tonight
Meanwhile, the shortwave colocated with the linear convective system
in Nebraska shifts east overnight and arrives in the Great Lakes
region late tonight/Saturday morning. It brings increased low level
moisture with dew points in the mid to upper 60s, but its connection
to the Gulf of Mexico is loose and the better moisture content
resides to our south. A low level jet slides through Saturday
morning, but it`s rather weak at around 10 to 15 kts, which allows
for just below adequate 25 kts of effective shear. This system
arrives in the morning meaning instability will be meager to just
beginning to grow. These signals indicate the system will initially
be weak. Of course, the HRRR is much faster with this system than
the NAMNest having it arrive at 9z and push through by 15z meaning
it would allow for better instability recovery ahead of an afternoon
shortwave. Even still, the later arriving NAMNest convects during
the afternoon/evening just after the departing morning
showers/storms. So, we`ll need to watch for how much influence
morning debris clouds have on the afternoon shower/thunder chance,
but the NAMNest and NSSL WRf don`t seem to be affected by
potential lingering debris cloudiness in a weak flow environment.
The shortwave approaching the area for the afternoon thunder chance
(barring cloud debris, after 2pm) looks to split with the northern
half taking a northeastward trek into southeastern Canada and the
southern part decaying as it arrives. The ECMWF indicates between
500 to 1000 J/kg of MUCAPE may be available for use by any storms
with the normally more juiced NAM indicating more. At this point,
the strongest flow appears disjointed with where we would expect
storms to form, but what flow does exist appears to have portions of
boundary parallel flow potentially with some pre-boundary cell
initiations. This would point to linear segments especially along
any remnant outflow boundaries along a with a few single cells.
Slower mid level lapse rates than 7 C/km likely takes large hail off
the table, but gusty to damaging winds appear possible, with the
storm mode being what it is, along with locally heavy rain.
Highs Saturday are actually slightly cooler than normal reaching the
mid to upper 70s although a few 80 degree readings cannot be ruled
out.
&&
.LONG TERM...(Saturday Night through Friday)
Issued at 300 PM EDT Fri Jul 7 2023
The long term will be dominated by strong ridging over Greenland, an
upper low over south central Canada and ridging over the
southwestern US and western Canada. This allows the Pacific jet to
intrude over the bulk of the United States with ridging
developing over the western US and troughing over the eastern US.
As the lagging cold front departs the area Sunday, it ushers in a
period of drier weather that continues into Tuesday as surface high
pressure and mid level ridging take over. Expect a warming trend as
lingering cloud cover gives way to increasing sunshine and warming
advection arriving Tuesday allowing low 80s on Sunday to become mid
to upper 80s for Tuesday.
Our next chance for showers and thunderstorms occurs later Wednesday
or Wednesday night as a Pacific shortwave arrives and the low level
jet initiates a moisture connection to the Gulf of Mexico bringing
back the humidity. With a mid level PV anomaly, a bulls-eye of
output precipitation, and an evolution that takes the system to the
southeast, it appears to be an MCS type system that may just scrape
our western counties.
For Thursday, a shortwave pinwheels around the upper low in Canada
allowing for pop storms within growing instability ahead of a
stalled cold front from Wednesday. However, if the aforementioned
MCS is able to dive southward, one would think that should allow the
cold front to dive south as well with the developing cold pool of
the MCS. Perhaps this discrepancy will get ironed out in future
model runs with either a more eastward trekking MCS into Wednesday
night or the thunder chance being removed for Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday Evening)
Issued at 747 PM EDT Fri Jul 7 2023
Predominantly VFR to MVFR conditions expected at the TAF sites
this period, with dips to IFR possible within the heaviest showers
and t-storms Saturday morning into the late afternoon. Phasing
northern/southern stream waves this period will congeal at or
around northern Indiana, with a strong LLJ and steep mid level
lapse rates lifting in by Saturday morning. First issue is how far
east decaying convection gets (which I`ve added VCSH in for), and
how quickly conditions decay to MVFR cigs/vis (and possible IFR).
Redevelopment and strengthening of the wave is expected as it
progresses eastward into the afternoon when there is better
instability. Most of the guidance keeps the ceilings mid range
MVFR or even VFR, so left out any IFR potential in the TAFs right
now-expect later shifts can add detail to those more significant
periods. Generally the 11-21z time frame is best for IFR
potential for KSBN, and 14-00z at KFWA (confidence is too low to
narrow timing down much further than this).
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...NONE.
&&
$$
SYNOPSIS...MCD
SHORT TERM...Roller
LONG TERM...Roller
AVIATION...MCD
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1050 PM CDT Fri Jul 7 2023
.SHORT TERM... (Through Late Saturday Night)
Issued at 257 PM CDT Fri Jul 7 2023
Showers and scattered thunderstorms with decaying MCS will continue
to move east across the northern CWA the next few hours. Latest
surface analysis is showing a warm front extending from central
Kansas into southeast Missouri. To the south of this front, SPC
mesoanalysis is showing MLCAPES in the 1000-3000 J/kg range. Latest
visible imagery is showing a well developed CU field to the south of
the warm front and the HRRR develops convection along and south of
the front late this afternoon into this evening. While the axis of
the best deep layer shear remains north of the instability, can`t
rule out one or two strong to severe storms tonight.
There will be some lull in the showers and thunderstorms overnight,
but should see a pickup in the activity again tomorrow morning and
early afternoon as the cold front over the northern Plains and upper
Midwest moves southeast across the area. Here again, could see a
strong storm or two tomorrow afternoon ahead of this front.
Temperatures will be a bit below normal tomorrow with clouds and the
front moving through during the day.
Britt
.LONG TERM... (Sunday through Next Friday)
Issued at 257 PM CDT Fri Jul 7 2023
Will continue with a chance of showers and thunderstorms over
southeast Missouri which will be unstable and in relatively close
proximity to the front. Then will keep Sunday night into Monday
night dry as there continues to be good ensemble agreement that a
surface high will move through the area under northwest flow aloft.
This flow will begin become more quasi-zonal as the ridge over the
Rockies flattens out which will allow a couple of shortwaves to move
across the area mid-late next week. This will also bring a surface
front into the area resulting in a chance of showers and
thunderstorms.
Highs on Sunday will be below normal with 850mb temperatures around
15C with northerly surface winds, but will climb above normal by
Tuesday as 850mb temperatures climb to around 20C with south to
southwesterly winds. There is more uncertainty in the forecast
Wednesday into Friday as both the 25th and 75th percentiles of the
ensemble forecast are showing a wider spread, likely because of the
front in the area. Either way, temperatures will likely be warm as
850mb temperatures will still be in the 15-20C range.
Britt
&&
.AVIATION... (For the 06z TAFs through 06z Saturday Night)
Issued at 1046 PM CDT Fri Jul 7 2023
Scattered showers are expected to pass through the forecast area
tonight, warranting VCSH at all terminals through sunrise. The St.
Louis metropolitan terminals may experience a round of thunderstorms
Friday afternoon as a cold front pushes southeast, but confidence is
low in where exactly thunderstorms will initiate. A deck of mostly
MVFR stratus will move into the forecast area from the northwest
very early Friday morning. Pockets of high end IFR may be embedded
within this stratus deck, so kept scattered IFR at most terminals to
account for this. Recent guidance is showing the deck lifting
slightly faster than before, but all terminals are still expected to
be locked in to MVFR until the afternoon. VFR conditions will
persist thereafter.
Jaja
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Memphis TN
953 PM CDT Fri Jul 7 2023
...New UPDATE...
.UPDATE...
Issued at 953 PM CDT Fri Jul 7 2023
A shortwave trough is moving across the Mid MS Valley this
evening, enhancing large scale forcing for ascent across the
Ozarks. Lift in this area is also aided by upper-level divergence
associated with an approaching jet streak and broad warm
advection aloft. The convection over the Mid-South, as well as
that over central and southern AR, has dissipated, but showers
and thunderstorms continue across north-central AR into southern
MO. The 00z CAMs have picked up on this activity but certainly
differ on its persistence over the next few hours. The last few
runs of the HRRR do not appear to have as good a handle on the
current activity as the previous (21-23z) runs and this time-
lagged approach is enough evidence for me to raise PoPs overnight
across northeast AR and the MO Bootheel to 40-50%.
This round of showers may evolve into the first wave for tomorrow,
affecting areas mainly east of the MS River after 12-15z. A
second, more robust, round of storms is more likely by mid/late
afternoon as the shortwave trough currently over the Southern High
Plains approaches the Mid-South. MLCAPE ahead of this second wave
may approach 2500 J/kg but deep-layer shear will still be rather
weak at only ~20-25 kts. Locally enhanced deep-layer shear should
be sufficient to organize updrafts into multicell clusters capable
of damaging wind and perhaps some marginally severe hail. Also on
the table is the potential for locally heavy rainfall. The
localized probability-matched mean QPF from the 12z HREF indicate
isolated pockets of 4+ inches of rain with more widespread amounts
between 1/2 and 1 inch.
MJ
&&
.SYNOPSIS...
Issued at 320 PM CDT Fri Jul 7 2023
Several rounds of thunderstorms are possible this weekend. Some of
the thunderstorms may become severe with damaging winds and
locally heavy rainfall as the main threats. Some locations could
see over 2 inches of rain this weekend. A more typical summertime
pattern with hot and humid temperatures and afternoon showers and
thunderstorms returns for most of the upcoming week.
&&
.DISCUSSION...
(This evening through next Thursday)
Issued at 320 PM CDT Fri Jul 7 2023
Scattered thunderstorms are moving slowly east across southern
sections of the Mid-South this afternoon. Skies are partly cloudy
across the region with temperatures mainly in the 80s to around 90
degrees. A weak frontal boundary is across north Mississippi at
this time.
This frontal boundary will continue to weaken tonight. Most of the
current thunderstorm activity will diminish by this evening with
most of the Mid-South having dry weather tonight and into early
Saturday morning. Temperatures will be near normal tonight with
lows Saturday morning in the upper 60s to mid 70s.
A new cold front will move into northwest Arkansas on Saturday.
Numerous showers and thunderstorms are expected to develop ahead
of the front and move across the Mid-South Saturday and Saturday
night. Some of the thunderstorms could be severe with damaging
winds as the main threat. Locally heavy rainfall is also possible
for both Saturday and Saturday night which could produce some
urban and small stream flooding issues. The clouds and
thunderstorm coverage will keep temperatures below normal on
Saturday with highs in the mid 80s to around 90 degrees.
The cold front will move into north Mississippi on Sunday with
more showers and thunderstorms mainly south of the front. Severe
thunderstorms will be possible on Sunday over north Mississippi
with damaging winds as the main threat. Locally heavy rainfall
will be possible again on Sunday.
The cold front will drop into central Mississippi on Monday with
scattered thunderstorms possible over the southern half of the
Mid-South. The front will be far enough south of the region Monday
night to keep any thunderstorms away from the Mid-South. The
boundary will start to head back north on Tuesday with showers and
thunderstorms returning to region ahead of the front. As the warm
front moves into the Mid-South on Wednesday, more scattered
showers and thunderstorms are expected to move through the region.
The warm front should fall apart across the region by Thursday
with another cold front heading toward the Mid-South from the
north. This front will bring more showers and thunderstorms to the
region. Behind the warm front, temperatures will return back to
near normal for Tuesday through Thursday.
&&
.AVIATION...
(00Z TAFS)
Issued at 615 PM CDT Fri Jul 7 2023
Confidence is increasing for two rounds of convection to effect
all sites tomorrow morning and again in the afternoon through
evening. VCTS and TSRA are likely at all sites. Brief periods of
MVFR/IFR conditions, as well as lower CIGS are possible.
Guidance hasn`t hinted at gusty/increasing winds, but FROPA
trends generally contain gusty winds. Gusty winds were left out
this TAF cycle, but will likely be added the next cycle. Some CAMS
are depicting isolated redevelopment after the line sweeps
through, but should still return to VFR and prevail by 04z
Saturday night.
DNM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
UPDATE...MJ
PUBLIC FORECAST...ARS
AVIATION...DNM
Area Forecast Discussion
National Weather Service Paducah KY
628 PM CDT Fri Jul 7 2023
...AVIATION UPDATE...
.SHORT TERM...(Tonight through Sunday night)
Issued at 337 PM CDT Fri Jul 7 2023
A warm front will move northeast across the FA through this evening
with more humid conditions. Dewpoints near 70 degrees are already
being observed across portions of SEMO where isolated pcpn is
possible through the rest of today. As a 500 mb impulse approaches
this evening, some of the 12z CAMs including the HRRR show isolated
convection developing along a boundary mainly across SEMO by 06-07Z.
Given MLCAPE over 1000 J/kg and steeper mid-level lapses rates of
6.0 to 6.5 C/km due to an increase in forcing for ascent, an
isolated strong to severe storm cannot be ruled out overnight with
gusty winds and some hail where SPC has a marginal risk in their D1
outlook.
The main concern then becomes Saturday as an influx in theta-e occurs
behind the aformentioned warm front causing dewpoints to surge into
the low to mid 70s. By midday, a 500 mb shortwave will approach the
FA with synoptic scale forcing, causing pcpn chances to ramp up
along the Mississippi River. One forecast question that remains is
how widespread will morning convection be across portions of
southeast Missouri and southern Illinois as this will have
implications on instability. Have adjusted NBM PoPs as they remain
to high with respect to the 12z CAMs. Overall, convection
coverage is likely to shift east and be the greatest during the
afternoon and early evening hours across southeast Kentucky and
southwest Indiana when peak heating occurs.
As for the severe weather potential, SPC`s D2 outlook has portions
of the CWA outlooked in a slight risk. Model thermal profiles show
1500-2000 J/kg of MLCAPE and effective bulk shear around 40 kts
which is sufficient for some severe storms. However, this once again
will be contingent on morning convection and cloud cover. The
greatest hazard of concern will be damaging wind gusts given DCAPE
values of 700-900 J/kg and low-level lapse rates of 8.0 to 8.5 C/km.
The 12z NAM in particular shows an EML between 600-500 mb which
would favor the wind potential if morning convection is limited.
Some hail is also possible in the strongest storms given mid-level
lapse rates between 6.5 to 7.0 C/km, but the tornado risk is very
low due to the lack of low-level shear. With PWAT`s between 1.75" to
2.00", locally heavy rainfall is also possible with QPF between
0.50" to 1.00" on average where convection occurs.
With that said, a cold front will sweep across the Ohio Valley
Saturday night providing quick relief from the humidity as dewpoints
return to the lower 60s on Sunday. Given the potential for some
radiational cooling Sunday night, bumped down low temps with a blend
of the NBM 25th percentile and CONSMOS. As for pcpn chances,
although the NBM maintains low chances for PoPs on Sunday, do think
most of the FA ends up being mainly dry as even the slower 12z ECMWF
is now more progressive with the frontal boundary. If an isolated
shower or storm were to develop, the greatest risk for pcpn would be
across the Kentucky Pennyrile.
.LONG TERM...(Monday through Friday)
Issued at 337 PM CDT Fri Jul 7 2023
Dry and tranquil conditions are in store for Monday and Tuesday as a
weak sfc high pressure builds across the Ohio Valley. Unsettled
weather and an increase in the heat and humidity is then in store
for the remainder of the week as a warm front moves through the FA
on Wednesday. A series of 500 mb impulses will then round the corner
of a 594 dam ridge parked across the southwest CONUS bringing the
risk for daily showers and storms. Due to the increase in humidity,
heat indices may near heat advisory criteria across portions of the
region by the middle of the week.
&&
.AVIATION...
Issued at 622 PM CDT Fri Jul 7 2023
Rounds of thunderstorms are possible tomorrow morning and again
afternoon through evening. A lot will be dependent on the morning
convection as to how the afternoon/evening convection sets up.
Models indicating the afternoon may be the better bet for storms
though and these would stand the better chance of impacting the
terminals. Have included PROB30s to indicate the chances for
direct impacts to the terminals.
Cigs with these storms could go MVFR at times along with visbys.
Winds will be fairly light except under storms where winds could
be stronger and variable.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...DW
LONG TERM...DW
AVIATION...SHAWKEY
Area Forecast Discussion
National Weather Service Pendleton OR
850 PM PDT Fri Jul 7 2023
.UPDATE...Isolated thunderstorms are diminishing over Grant and
Crook Counties and the balance of the night should be dry. Decided
to issue a heat advisory for Saturday and Sunday for the Lower
Columbia Basin of Washington. Heat risk prototype is getting into
the major category (heat affects anyone without effective cooling
or hydration) in a fairly sizable portion of that zone during the
period. In addition to the triple digit heat both days it will be
warm Saturday night with overnight lows close to 70. The advisory
area may need to be expanded on subsequent shifts. The other
concern is thunderstorms for Saturday afternoon and evening for
central Oregon. Decided to add to the Red Flag Warnings already
issued for OR640 and OR642 a watch for 640 for abundant
lightning. Mitigating factor includes the meager instability but
the HRRR moves multiple rounds of convection through during the
afternoon and evening. The greatest instability is actually along
the WA Cascade east slopes but the 00Z HRRR and the 12Z HREF did
very little there in terms of convection. Thus held off on any
highlights in central WA for now. A significant shortwave trough
will move through the region Monday which could lead to a more
widespread shower/tstm event along with an increase in winds. 78
&&
.PREV DISCUSSION... /issued 420 PM PDT Fri Jul 7 2023 /
SHORT TERM...Today through Sunday...Heat and the chance for
mountain showers and thunderstorms will continue to plague the
forecast area throughout the weekend. Weak zonal flow to ridging is
to blame for the rising temperatures, which will slowly be replaced
by a band of SW flow that guidance suggests will impact our forecast
area throughout much of the next week.
As far as the chances for mountain showers/thunderstorms is
concerned, forecast has been tricky as models tend to be more
bearish this time of year in depicting convection due to hot and dry
conditions, however most recent CAMs are beginning to tap into the
oncoming Pacific moisture, depicting isolated to scattered storm
activity across the central and eastern mountains of Oregon, as well
as portions of the central WA Cascades. Already seeing some isolated
cells fire off this afternoon in Grant County despite a relatively
dry air mass, so this further increases the confidence in storm
activity over the weekend for the aforementioned areas. Went ahead
and issued a Red Flag Warning for the John Day/central Blue
Mountains area for Saturday, as guidance depicts plentiful mid-level
moisture for the area, with CAMs depicting isolated to scattered
storm activity. This, combined with the recent heat, should be
enough for abundant lighting to trigger new fire starts. Biggest
confounding variable would be the moisture content in the
atmosphere, as models depict PWATs as high as 0.8 for the area, so
some storms over the RFW area could be wetting in nature. That being
said, given the isolated to patchy coverage of storms, plenty of
lighting strikes could occur away from the thunderstorm core, so
will err on the side of caution and not presume that the storms will
be wet enough to preclude a risk of new fire starts.
Confidence is shaky for storm coverage on Sunday as CAMs don`t go
out far enough and global guidance is lackluster on coverage, yet
the synoptic set-up still favors storm generation, spreading even
into the lower elevations. Left coverage of slight chance to chance
PoPs for the areas that are expected to receive storms on Saturday
as well, but remains to be seen whether or not Sunday will be
supportive of RFW conditions once again.
With all this talk of a Pacific moisture surge via SW winds aloft,
the most recent temperature forecast has moderated itself a bit as
models seem to be tapping into the higher moisture content aloft.
Still seeing daytime highs forecasted just into the triple digits
for the lower Basin, especially on Sunday which continues to be the
hottest day forecasted. However, Sunday previously looked to be a
potential heat advisory day, but now looks less so with the highs
ticking down a bit according to the latest guidance. Will be
interesting to see if Sunday continues to track cooler if models
start to better capture the oncoming moisture flow over future runs.
Otherwise, still expecting widespread mid to upper 90s (at least)
across our population centers throughout the weekend. Evans/74
LONG TERM...Monday through Friday...The beginning of the forecast
period will prove to be the most active day in the period.
Confidence that critical fire weather thresholds will be met is
moderate (50-70%) and these conditions will continue to be monitored
as the event draws near. Temperatures will dip for a brief period
Monday before slowly trending upwards again through the period.
Monday models are in firm agreement that an upper level shortwave
will traverse across the region and exit by Tuesday morning. This
new pattern will bring with it a few changes in temperature, winds
and weather. The shortwave will cause a tightening of the surface
pressure gradients over the Cascades causing increased winds across
the area, especially through the Cascade Gaps along the foothills of
the Blue Mountains and the southern portion of the Basin. Winds are
expected to range between 10-20 mph with gusts to 35 to 45 mph
possible. Some isolated locations could see sustained winds 25-30
mph. The shortwave will also bring temperatures a few degrees
cooler, however the EFI does show that the area will continue to be
slightly above the climate normal. Ensembles and the NBM show highs
will be in the low to mid 90s through the Gorge, Basin and along the
foothills of the Blue Mountains, 80s through Central Oregon and the
John-Day Basin, with 70s near the higher terrains. Also, models are
showing an influx of some upper level moisture, PWATs nearing 0.1-
0.3inches available, elevated CAPE values of 150-350J/kg and steep
lapse rates of 7.6-8.1C/km has increased awareness of early morning
and late afternoon thunderstorms across the WA Cascades through the
Basin and into Wallowa County although confidence is marginally low
at this time so only slight chances were forecasted (<20%).
Tuesday the models show west-southwest flow returns and a slow
warming trend begins. Wednesday is the next day with weather
activity albeit not as strong of a signal as Mondays shortwave.
Wednesday models are in relatively firm agreement that another upper
level shortwave will traverse over the region bringing again
slightly increased winds across the area. No precipitation is
expected with this shortwave as all models show very little to no
moisture transport. The shortwave will exit the region by Wednesday
and westerly to southwesterly flow aloft will return and remain
through the period. Temperatures will peak on Friday but mostly only
by a degree or two warmer than the previous days. Again, EFI
continues to show the area above normal. Bennese/90
AVIATION...00z TAFs...VFR conditions with just a few mid and high
clouds through the period. Isolated to scattered thunderstorms on
Saturday over the central and northeast ORE MTNS should stay mostly
east of TAF sites KBDN and KRDM with a 10% to 15% chance of a storm
impacting those sites. Winds will be sustained 4-12 kt and terrain
driven except 15G25 kt at KDLS. 78
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 63 94 65 96 / 0 0 10 10
ALW 67 98 68 101 / 0 0 0 10
PSC 66 100 69 102 / 0 0 10 0
YKM 65 98 67 98 / 0 0 10 0
HRI 66 99 68 101 / 0 0 20 10
ELN 63 98 65 96 / 10 0 10 10
RDM 54 90 56 91 / 0 10 30 10
LGD 59 92 63 95 / 0 10 10 0
GCD 58 90 60 95 / 20 40 30 10
DLS 62 92 62 93 / 0 0 10 0
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning from 11 AM to 11 PM PDT Saturday for ORZ642-644.
Fire Weather Watch from Saturday morning through Saturday
evening for ORZ640.
WA...Heat Advisory from noon Saturday to 8 PM PDT Sunday for WAZ028.
&&
$$
SHORT TERM...78
LONG TERM...90
AVIATION...78
Area Forecast Discussion
National Weather Service Raleigh NC
941 PM EDT Fri Jul 7 2023
.SYNOPSIS...
A surface trough will remain in the lee of the southern and central
Appalachians through Saturday.
&&
.NEAR TERM /TONIGHT/...
As of 930 PM Friday...
A surface trough and numerous outflow boundaries led to countless
storms this afternoon and evening. Drier air aloft moved into the
region this afternoon, and helped to provide higher DCAPE, which led
to gusty microbursts in storms, some of which knocked down trees and
power lines. Hail up to the size of a half-dollar was reported near
Fuquay-Varina, with a few other reports of 1 inch hail observed this
afternoon. Most storms have diminished from lack of diurnal heating,
however the front right quadrant of an upper jet moving across the
area will help maintain isolated showers/thunderstorms through early
tonight. Precipitable water values near 2 inches across the Coastal
Plain could continue the threat of heavy rain and isolated flooding
with any storms that develop. Patchy fog/mist may develop again
tonight, with persistent muggy lows in the upper 60s to low 70s.
&&
.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
As of 350 PM Friday...
Saturday and Saturday night: Not quite as hot, but with a
persistence forecast of scattered afternoon-evening showers and
storms.
A couple of weak shortwave perturbations evident in water vapor
satellite data over nern MS and s-cntl AL early this afternoon will
pivot across the South Atlantic coast on Sat, while a couple of more-
vigorous ones amplify and may partially phase from the mid MS to TN
Valleys Sat night. The cntl Carolinas will generally remain in
between each of these regions of synoptic forcing for ascent and
stronger flow, in a region characterized by a mean wswly wind of
only around 10-15 kts and which may include a couple of weak MCVs
from today`s convection across GA and the Carolinas. The strongest
of these MCVs will likely be one from a relatively stronger
convective cluster with colder cloud tops now over cntl GA, which
the RAP directs across the NC Sandhills and Coastal Plain Sat
afternoon.
At the surface, a persistent, southern and central Appalachian-lee
trough will remain directly over the srn middle Atlantic and
Carolinas. The models also suggest some very weak cooling of 925-850
mb temperatures may accompany a weakening cold front as it crosses
the middle Atlantic and merges with the lee trough through Sat.
The sensible weather resulting from the pattern described above will
feature much of the same as previous days, with above average high
temperatures and scattered, diurnal convection. Temperatures will
likely be a degree or three cooler than those of today (Fri),
however, owing to both a canopy of mid to high-level cloudiness and
weak cooling behind the aforementioned weakening cold front.
The surface trough will again provide the initial focus for pulse-
type convection, with some local enhancement to coverage along the
ultimate track of any MCVs, which appear at this time to most likely
influence the NC Sandhills through Coastal Plain. Convection should
wane with nocturnal and diabatic/outflow cooling by mid-evening,
with persistence low temperatures in the upr 60s to lwr 70s.
Sunday and Sunday night: As of Sunday morning, a surface low should
be across western Ohio with a cold front extending to the southwest.
The low should move to New York City by Monday morning. The arrival
time of the cold front still remains a bit up in the air, with the
front likely to approach central NC around sunset Sunday.
Precipitation coverage appears to be a bit more scattered on most of
the 12Z guidance suite compared to previous runs, although a potent
upper shortwave should combine with the front to provide good
coverage of rain across the area. CAPE values exceeding 2000 J/kg
and effective shear values approaching 30 kt will bring a threat of
severe weather to most of the forecast area, with all locations
included in a slight (level 2 of 5) risk from the Storm Prediction
Center. The primary threat will come from damaging winds, although
large hail will also be possible. At this time, low level wind
conditions do not look particularly favorable for tornadoes. Most
locations are also under a marginal (level 1 of 4) risk for
excessive rainfall, especially if storms are training over the same
location. High temperatures should be slightly cooler in most
locations on Sunday considering the widespread cloudy conditions,
although temperatures could be a little bit higher in the southeast
where the chances of rain are the least. Expect little change in the
overnight temperatures.
&&
.LONG TERM /MONDAY THROUGH FRIDAY/...
As of 300 PM Thursday...
On Monday the mid/upper level trough along with the surface cold
front will be slowly shifting east and offshore by Tuesday morning.
On the back side of the trough there is expected to be some left
over instability and moisture on Monday as it exits the area, thus
another round of strong summertime pulse storms will be possible
Monday. As the front moves across the region, temperatures on Monday
will be about 3 to 4 degrees below average. Highs will be in the low
to mid 80s across the area with lows in the low to mid 60s.
Along the frontal boundary, a secondary weak surface low develops
over MS/AL on Tuesday and is expected to shift NE in the GA/SC
region as a surface high pressure builds in from the Ohio Valley and
over NC. Tuesday will start off mostly cloudy for areas in the SE
but expect mostly sunny skies Tuesday and Wednesday as a weak high
pressure influences the area. By Thursday the front and associated
low pressure will move east and offshore while another front moves
over the Ohio valley and into the Mid-Atlantic late week. Increased
rain chances for Thursday and Friday afternoon with highs in the mid
to upper 90s and heat indices in the low 100s.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 749 PM Friday...
24 hour TAF period: A few isolated storms will continue between KRDU
and KFAY through 1000 PM; otherwise, a return to VFR conditions are
expected for all areas by late evening. Patchy MVFR fog and some
scattered low stratus can be expected around sunrise in the east.
There is a chance of scattered storms again on Saturday afternoon
and evening, particularly in the east.
Outlook: There is a chance of thunderstorms on Sunday afternoon and
evening; otherwise, generally VFR conditions are expected Sunday
night through Tuesday.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS/np
NEAR TERM...JJT
SHORT TERM...MWS/Green
LONG TERM...CA
AVIATION...PWB