Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/10/22
Area Forecast Discussion
National Weather Service Gray ME
949 PM EDT Tue Aug 9 2022
A cold front will gradually sink south of the region tonight...
allowing much cooler air to filter into the region for the day
on Wednesday. Another cold front will approach the region on
Thursday with some scattered showers. The weather turns drier
and cooler for Friday and Saturday as low pressure passes well
east of New England. A slow warm up is expected next week.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
945PM Update...No significant updates with this package, mostly
just tweaked timing of cloud cover and trimmed back pops a bit.
Backdoor front and marine push is just about reached the CT
River Valley. This marine push will lead to a cool and moist
night for the entire region, kept the mention of drizzle, but
mostly confined to the mountain areas with NE upslope winds
favoring the higher terrain. Some fog is possible but not
expecting that much with the low level stratus deck firmly in
place across the region already. A few spotty showers remain,
but only a few hundredths of precip is expected before shower
activity mostly ends after midnight.
630PM Update...Backdoor cold front is currently pushing into the
Merrimack River Valley at this hour. It will finally bring
relieve and end to the historic heatwave that impacted Southern
New Hampshire over the past week. The marine airmass behind the
front is cool with most areas behind the front in the mid to
upper 60s. With the strong Canadian Maritime airmass push,
upslope drizzle is expected in the mountains with low clouds
behind the front. A few spotty showers are developing on the
frontal boundary, but overall just some hit and miss rainfall,
with no drought relieve type of rain with this boundary passage.
The wavering frontal boundary with waves of low pressure tracking
along it will finally shift south of the area for good tonight.
Before the boundary shifts to our south it will provide a focus for
showers and possibly a couple of thunderstorms across southern New
Hampshire and SW Maine. The latest RAP analysis shows a wedge of
MLCAPE in the 1000 to 1500 J/kg range juxtaposed with around 35 kts
of effective shear across southern New Hampshire into York and
Cumberland Counties. Latest radar shows a few showers tracking
across eastern NH and SW Maine with the bulk of lightning
activity remaining to our south over Massachusetts. CAMs have
been quite bearish on convective coverage where there is
currently sufficient instability through this evening
advertising more in the way of showers than thunderstorms. Given
recent trends in CAM guidance and trends in a boundary pushing
SW down the Maine coast... forecast thinking is along the lines
of scattered showers with occasional instances of thunder
rather than scattered strong thunderstorms through sunset. By
sunset the boundary will be south of the area with low level
easterly flow overspreading the remaining southern areas. This
will usher in cooler air and ending the oppressive heat and
humidity for all areas.
Tonight low level easterly flow will continue with mostly cloudy
skies. BUFKIT soundings most of the area will see low level
saturation below 800 mb although dewpoint depressions at the
surface look to be large enough to inhibit widespread fog.
Current forecast thinking leans more towards low ceilings with
patchy fog across northern valleys and isolated showers or
possibly drizzle. Lows tonight will drop into the 50s across the
north to the low 60s across the south.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Wednesday will be much cooler with highs ranging from the upper
60s north to upper 70s across southern New Hampshire and the CT
Valley. Skies will be mostly cloudy to start with thinning cloud
cover going into Wednesday evening. Broad cyclonic flow aloft
will bring the threat of a stray shower while most areas will be
Troughing over eastern North America starts to deepen Wednesday
night with skies turning mostly cloudy towards Thursday morning.
There will be slight chances for showers across the southern
half of the area along with patchy fog in sheltered inland
locations and along the coast. Lows will range from the mid 50s
north to mid 60s south.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
High Impact Weather Potential: Minimal.
--Pattern and Implications--
The long term forecast period opens with a pattern change as
longwave troughing over eastern Canada drops into the northeastern
United States to end the week. Another longwave trough will reside
across the eastern Pacific with longwave ridging near the spine of
the Rocky Mountains. This overall flavor to the mid and upper level
flow pattern will remain relatively unchanged through the weekend
and into early next week. The aforementioned trough sharpens
overhead this weekend with low pressure developing east of the
region and moving into the Canadian maritimes. Beyond this into
early next week...the ensemble consensus favors shifting the
longwave trough axis to a position just west of our region.
Thus..the temperature trend will be downward into the weekend with
the arriving trough and then slowly back upward early next week as
heights rise. However...no return to significant heat/humidity is
expected in the long term given this overall change in the synoptic
As for precipitation chances...some chances will exist to open the
period on the front end of the arriving trough/associated cold
front. Through the weekend...though the ensemble consensus does not
favor much in the way of widespread precipitation...an upper low
overhead suggests at least a chance for a sprinkle or shower. We
will likely turn dry for a period late Sunday into Monday as the
trough re-orients further west with increasing moisture portending
more precipitation chances towards the very end of this forecast
Thursday - Friday: Period opens with a cold front over the eastern
Great Lakes as a longwave trough builds towards the region. 1.5 PVU
surface jet streak over 100kt will be anchored over northern Maine
which...combined with upstream trough should allow for cyclogenesis
south and east of New England. Moisture builds along the advancing
cold front with PWATs around 1.5" in a ribbon along the front. With
the mid/upper level flow amplifying and surface low taking shape
southeast of New England...the forward progression of the front will
slow...and provide a focus for shower development despite more
significant forcing being located offshore. Given the offshore low
development...expect a decent amount of cloudiness even well ahead
of the front...so while some destabilization is expected...do not
currently expect a significant thunderstorm threat. Airmass ahead of
the front is warm /T8s nearing 15C/ but cloud cover will limit
heating with mid 70s to lower 80s likely for highs. Front washes
out as it crosses the region Thursday night with northerly flow
bringing drier air into the region on Friday with T8s falling
towards or a bit below 10C...which should keep mountain locations
right around 70...with a downslope component further south allowing
highs in the upper 70s to around 80 to the south. This will set the
stage for much cooler lows Friday night with clear skies and
diminishing winds allowing lows to fall into the 40s in the
mountains with 50s to the south and east.
Saturday - Sunday: Trough axis will be directly overhead to start
the forecast period Saturday with this trough sharpening and
spawning low pressure south of Nova Scotia which remains well east
of the region. The upper low moves from being overhead Saturday to
north and east of the region on Sunday. T5s at the core of this low
fall to around -15C though the westward tilt of the system with
height suggests some warmer air below this level. Thus...despite
cool temperatures aloft...model profiles suggest a capped
airmass with little signal for shower chances. There remain some
differences on the overall evolution of the core of the upper
low and it/s interaction with the downstream surface low...but
can/t rule out a shower either afternoon...especially in the
mountains. T8s will remain at or a bit below +10C on
Saturday...moving just above +10C for Sunday. Therefore a much
cooler weekend is in store than the previous with highs mostly
in the 70s to around 80 from north to south Saturday warming
into the mid 70s/lower 80s for Sunday under partly cloudy skies.
Monday - Tuesday: Heights begin to rise across the northeastern
United States with longwave trough relaxing before reloading from
the west. High pressure at the surface should allow for a dry day
Monday before precipitation chances slowly increase on Tuesday
depending on the speed of the reinforcing shortwave trough. T8s
will remain in the 11-13C range...perhaps warming just a bit from
Monday into Tuesday. This should result in seasonable
temperatures...with highs in the 70s in the mountains and lower 80s
from the foothills south.
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Frontal boundary across southern Maine and New
Hampshire will shift south tonight with cigs lowering to
IFR/LIFR thresholds and patchy fog bring vsby restrictions to
all terminals. Cigs lift to MVFR thresholds Wednesday morning
and VFR thresholds Wednesday afternoon. Low cigs and patchy fog
will likely bring IFR to LIFR conditions again Wednesday night.
Long Term...Showers and an isolated thunderstorm are possible
Thursday afternoon and Thursday night which will allow for
scattered MVFR restrictions. Beyond this VFR conditions should
dominate the Friday-Sunday period outside of overnight fog
potential each night at HIE/LEB.
Short Term...Winds and seas are expected to remain below SCA
thresholds through Wednesday night. Frontal boundary dropping
south across the waters this evening will shift winds out of the
NE tonight with winds shifting out of the E to SE late
Wednesday and then S Wednesday night.
Long Term...Winds and waves are currently expected to remain
below SCA levels through the period. Low pressure is expected to
pass well south and east of the waters late Friday through
early Saturday. If the track of this low were to move west
somewhat...a period of SCAs would be possible due to gusty
northerly winds either Friday night or potentially on Saturday.
Area Forecast Discussion
National Weather Service Paducah KY
506 PM CDT Tue Aug 9 2022
Issued at 501 PM CDT Tue Aug 9 2022
Updated Aviation discussion for 00Z TAF Issuance.
.SHORT TERM...(Tonight through Thursday night)
Issued at 318 PM CDT Tue Aug 9 2022
Pinpointing times/locations of best chances of convection this
afternoon through Wednesday remains challenging as models have
been overdoing the coverage thus far. At this time, a blend of
the more extensive coverage RAP and minimal coverage HRRR is a
decent solution through this evening, resulting in scattered
showers and thunderstorms across our entire region through mid
evening. Loss of heating should result in more isolated to widely
scattered showers and thunderstorms overnight.
The cold front helping to set off this activity is currently
sinking into our far northern counties, and models show the front
bisecting the PAH forecast area basically along the Ohio River
into southeast Missouri by 12z Wednesday. The highest chances will
be along and southeast of the front, which will put the best
chances across west Kentucky by late tonight and through the day
Models show the frontal boundary meandering across, then just
south of west Kentucky into early Thursday. Chances of showers and
storms will continue across our entire area Wednesday morning,
then dry conditions will return to our northwest counties
Wednesday afternoon. Chances will continue primarily across just
west Kentucky Wednesday evening, with convection ending during the
overnight hours. Isolated showers and storms will again be
possible across southern portions of the Pennyrile region on
Thursday, then Thursday any chances will move away from our area.
The passage of the front will result in temperatures being a
little below normal, and dew points will gradually drop from the
lower to middle 70s today, to the upper 60s to lower 70s
Wednesday, to the upper 60s area wide Thursday.
.LONG TERM...(Friday through Tuesday)
Issued at 318 PM CDT Tue Aug 9 2022
Cooler than normal temps are in store to end the week as the FA will
be sandwiched between a deep 500 mb trough along the East Coast and
a large 500 mb ridge centered over the Plains. This will establish
north to northeast winds at the sfc supporting dry conditions and
lower humidity in addition to the cooler temps. With sfc high
pressure moving across the Great Lakes region on Friday, highs will
be in the lower 80s and dewpoints well into the 60s.
For Friday night, light variable winds combined with mostly clear
skies will allow for some radiational cooling to occur with lows
nearing 60 degrees. Dewpoints may even reach the upper 50s along I-
64, meaning conditions will be ideal to give the AC a much needed
Saturday will be the nicest day of the weekend as highs will be
similar to Friday in the low to mid 80s with sufficient diurnal
heating. Heading in Sunday, dry conditions along with slightly
warmer temps is still looking likely as the latest 12z GFS which has
been the most progressive in bringing QPF to the FA has slowed down
quite a bit. With the best theta-e and 850 mb warm moist advection
now holding off until Monday, it is more likely any slight chances
of pcpn progged by the NBM hold off until later Sunday night across
our northern counties. The big forecast question for Monday is if a
500 mb impulse rounds the corner of the 500 mb ridge over the Plains
as this would bring a better risk for showers and thunderstorms
during the day. Chances for pcpn continue into Tuesday as a series
of disturbances will approach the FA from upstream.
Issued at 501 PM CDT Tue Aug 9 2022
The surface front looks to extend from near KOWB, to just south of
KPAH-KCGI. Active convective chances persist near its boundary,
but radar shows mainly VC mention from KEVV-KOWB for a short while
longer is perhaps best, with silent chances thereafter. MOS
guidance suggest potential CIGS/VSBYS restrictions overnight with
fog/low cloud, so we`ve included that in this issuance and will
monitor trends behind the front as the night progresses. The
boundary`s still near vicinity tmrw will serve as a focus for
showers/storms again, with diurnal fueling.
Area Forecast Discussion
National Weather Service Pendleton OR
456 PM PDT Tue Aug 9 2022
.Updated Aviation Discussion.
Short term...Today through Thursday...
Active weather today and into tomorrow morning. Current radar is
showing a robust cell down in Deschutes County that is putting off a
few good pulses of lightning. A Red Flag warning is in affect for
the abundant lightning expected through Central Oregon until 9 PM
tonight. Short term HRRR model is showing some decent QPF and PWAT
values, so these storms will likely produce some moderate to heavy
rainfall rates. Strong outflow winds will also accompany any
developing storm cells, as some observations taken earlier in the
day have reached near 50 mph.
The SREF/HRRR short term models as well as the GFS/ECMWF and NAM
models are in fairly good agreement with the placement of the low
off the coast. Currently the low is sitting off the coast of
Northern California and the leading edge is just onshore, while the
ridge has begun to breakdown. The far edge of the ridge is pressed
right up against the low creating the perfect combination to draw
some of the monsoonal moisture from the Four Corners into our area.
The HRRR is showing some significant CAPE values over much of
Central OR and moving into the eastern region of the CWA by tomorrow
morning. Highs will be the mid 80s to 90s, a bit lower than
originally forecasted due to the intermittent cloud cover and
The rest of today we will see the storms continue to progress north
and eastward through the region. VIS satellite is showing a nice
clearing across much of the Basin, so daytime heating will allow for
some convective build up as the moisture moves over the region later
this afternoon. Chance of showers and thunderstorms for much of the
southern and eastern portion of the CWA and a slight chance of
showers elsewhere. Highs will be the mid 80s to 90s, a bit lower
than originally forecasted due to the earlier cloud cover this
Wednesday, the models are still in tight agreement with the
placement of the low. They are showing the low will be just of the
coast of Oregon and slightly closer to shore. With the moisture
still being pushed in from the south, there is a slight chance of
showers mainly over the Northern Cascade crest and eastern Oregon in
the morning. By late morning as instability increases with sunrise,
chances of thunderstorms will increase over those same locations
until tomorrow night. Dry conditions will prevail through the
remainder of the evening and into the remainder of the forecast
period. The remainder of the period will be dry with temperatures in
the upper 80s to mid 90s with a few localized 100s and locally
breezy winds. Bennese/90
LONG TERM...Friday through Tuesday...Mostly benign weather
with above-normal temperatures is currently expected for the long-
term period. Ensemble cluster analysis reveals the main uncertainty
in the longwave pattern revolves around the progression of the upper-
level low currently situated offshore and an impending ridge for
Monday and Tuesday.
Friday and Saturday, locally breezy conditions are forecast through
the Cascade gaps during the afternoon and evening, driven by cross-
Cascade thermal and pressure gradients as the upper-level low
eventually lifts into British Columbia. With our CWA under diffluent
SW flow, could see some shower and thunderstorm development Friday
afternoon and again Saturday afternoon across the mountains,
provided there is enough moisture, but confidence is low at this
time. Flow aloft will weaken should the most likely scenario
(unperturbed southwest flow aloft) verify, though clusters do
suggest a roughly 25% chance of the upper low just pushing onshore
by Sunday. Should the latter solution verify, locally breezy
conditions through the Cascade gaps, with slightly cooler
temperatures would occur Sunday. Heading into Monday, the most
likely solution is ridging beginning to build across the Pacific
Northwest, with this trend continuing for Tuesday. Some heat
concerns may develop Tuesday and beyond with many ensemble members
suggesting 100-110 in the Lower Basin and Foothills of the Blue
.AVIATION...00Z TAFS...VFR conditions expected through the period
with the exception of localized MVFR/IFR categories in and
around thunderstorm and shower activity this afternoon into
tonight due to decreased visibilities and ceilings. Synoptic winds
will subside this evening and tonight before picking back up to
10-20 kts at KDLS, KRDM, and KBDN Wednesday morning and
afternoon. Winds will be gusty and erratic in and around
thunderstorms, with gusts of up to 50 mph possible. Plunkett/86
.PRELIMINARY POINT TEMPS/POPS...
PDT 68 97 60 91 / 30 20 0 10
ALW 71 98 64 93 / 30 20 10 10
PSC 73 100 67 95 / 20 10 10 0
YKM 67 97 60 94 / 30 10 0 0
HRI 70 99 64 95 / 30 10 0 0
ELN 67 97 61 93 / 20 20 10 0
RDM 57 93 49 90 / 40 0 0 0
LGD 65 94 58 90 / 40 40 20 20
GCD 62 96 56 95 / 60 20 10 0
DLS 68 87 62 93 / 30 10 0 0
OR...Heat Advisory until 11 PM PDT this evening for ORZ041-044-049-
Red Flag Warning until 9 PM PDT this evening for ORZ611-640-642-
Red Flag Warning until 6 AM PDT Wednesday for ORZ610.
WA...Heat Advisory until 11 PM PDT this evening for WAZ024-026>029-
Area Forecast Discussion
National Weather Service Phoenix AZ
529 PM MST Tue Aug 9 2022
Updated Aviation section.
Elevated chances for showers and thunderstorms will continue the
rest of the week and into early next week. Occasionally heavy
rainfall, localized flash flooding, gusty winds and localized
blowing dust remain likely through early next week. High
temperatures will remain below to near normal through the forecast
The midlevel Monsoon ridge remains optimally located near the S-Cent
Rockies with moist E undercutting flow through the mid-upper
levels aloft. WV imagery reveals a very moist airmass across the
region with a number of E waves/inverted troughs pushing W and NW
into/through various parts of the region including N, E and S-SE
AZ, SE CA/La Paz Cty, where GOES imagery and radar also indicated
an area of scattered showers and storms, with localized flash
flooding occurring this afternoon, including I-10 E and W of
Early afternoon radar also showed widely isolated to
scattered distant thunderstorms across the high terrain of N, E
and S-SE AZ. Both the E AZ/W NM and S-SE AZ storms were
associated with additional, possibly linked E wave(S) advancing
from those areas. The latest ACARS soundings showed an
anomalously moist airmass with PW maintaining near 1.7->1.9" while
mesoscale analysis indicated PW of 1.5->2" and Mean W of 10->14
g/kg across SW-W and S-Cent AZ and into SE CA. MU and SB CAPE had
also increased to >1.7-1.8K j/kg around Phoenix and >2k j/kg
across the W deserts.
In a seemingly virtual repeat of yesterday, HREF members still favor
pronounced convection with locally heavy rainfall developing this
afternoon across S Gila Cty and near Globe and burn scar areas
before descending into the lower deserts and parts of the Phoenix
Metro during the evening hours. With the regional Flood Watch now
underway through late tonight, and with the WPC Day 1 ERO
indicating the large "Slight Risk" area, any convection that
develops will have sound potential to produce locally heavy
rainfall as well as localized flash flooding.
Also like yesterday the HRRR has once again become an outlier and
has again backed off on that scenario by both delaying and
weakening the convection coming off of the high terrain this
evening. This is the result of a festering MCV, light showers and
cloudy/mostly cloudy conditions that significantly delayed surface
heating this morning across most of the Phoenix Metro. This
supported elevated levels of CIN well into the day around Phoenix.
However the 12Z HREF ensemble still indicated a gusty SE outflow
this evening pushing into the Phoenix metro and N Pinal as well as
colliding outflow signals late tonight W-SW of Phoenix. The
potential for patchy blowing dust moving NW remains possible,
although remains most likely for N Pinal Cty and the SE-E Phx
Metro Valley where there is a 10-30% chance of max sustained storm
outflow wind speeds of >35 mph this evening.
Also like a repeat of yesterday`s progs, tomorrow the HREF and
ensembles are in agreement on an increase in storm chances and
coverage from E to W across the region with POPs increasing to near
50% for Phoenix and the lower deserts and the E AZ high country, and
20-30% for SW AZ and SE CA. Some HREF members start with some
shower activity W of Phoenix in the Wed morning hours moving in from
in S-SE AZ. However the main convection will likely start in E-SE AZ
associated with the next E wave(S) and will push into the Phoenix
Metro and the lower deserts Wed evening.
For Wed evening the HREF indicates an even better 30->50% chance
of max sustained storm outflow wind speeds of >35 mph from both
the S-SE and E and locally dense blowing dust. Also indicated is a
>10% chance of sustained max outflow winds >57 mph along the
infamous I-10 dust corridor just south or the CWA (or S of Eloy
AZ near Picacho Peak). This would likely be followed by locally
heavy rainfall and additional localized flash flooding in the high
country and the lower deserts.
Looking more broadly for the rest of the week and into the
weekend, major weather features include the mid level anticyclone
centered near Four Corners and a rather deep upper level low off
the northern CA coast. The low is expected to lift north,
amplifying the anticyclone and shifting the center a little
further north and east through the week. This will enhance the
undercutting easterly flow across Southwest. EPS/GEFS/CMC resolve
this, with H5 heights anomalously higher over the Pacific
Northwest, indicating an even broader easterly flow is likely by
this weekend. Until then, PoPs remain elevated with continued
chances of showers and thunderstorms each day across the entire
Several EPS and GEFS members latch onto a significant wave moving
through the Southwest around Saturday (give or take a day for
uncertainty). The EPS-based EFI QPF data has an interesting
signal in that the majority of members are not forecasting
climatologically high rainfall, but there are a small minority of
members that are predicting QPF outside the model climate for
August. This aligns with an axis of enhanced instability and
moisture emanating north out of the Gulf of California and arcing
NNE into southern Idaho. Digging a little deeper through cluster
analysis of the global ensembles, the details of this will really
depend on the evolution of the upper level low to our northwest. A
deeper solution (favored by 1/3 EPS and 1/2 CMC but just one GEFS
members) would increase wind fields and moisture flux resulting
in greater precip potential. Even the NBM is indicating non-zero
chances for 24-hr QPF of 1"+.
Given the increased cloudiness and moisture through the forecast
period, high temperatures will likely (~80%) remain below daily
normals. Temperature variability is quiet high, especially around
the weekend with the potential influx of even higher moisture and
clouds (NBM IQR for Sunday`s high temperature is 96-105F).
HeatRisk levels will remain in the Moderate category across SE CA
through the week with Low expected across most of Arizona - thus
some heat impacts are possible especially for those with greater
exposure or those exerting themselves outdoors. With many schools
going back in session, it`s worth reminding kids (and
teachers/faculty) to pace themselves and hydrate appropriately.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Storms to the north, east, and south of the Phoenix over
southeast and eastern AZ have been isolated with newer development
over southwest Maricopa County. Outflow that had been approaching
from Pima County has weakened. Given the lack of more robust
activity, and convective inhibition evident in aircraft sounding
data, have removed the mention of VCTS from the TAFs. However,
storms over southwest/west Maricopa County could produce outflow
that potentially reach the the TAF sites. As has been seen a
number of times this Monsoon season, late night shower and
thunderstorm activity will be possible, but would expect it to be
weaker than last night and more isolated (if it happens at all).
Apart from outflows, light west and northwest winds will prevail
before trending toward light easterly late tonight. As for sky
cover, expect increasing mid and high clouds as the night
progresses followed by thinning during the day Wednesday.
Southeast California/Southwest Arizona including KIPL and KBLH:
KIPL: Thunderstorms are ongoing in the vicinity of KIPL with gusts
of 30-35 kts and blowing dust dropping visibility below 6SM.
Anticipate erratic winds and at least one downpour reducing vis to
between 2SM - 4SM along with ceilings to between FL070-090.
Anticipate significant decline in storm activity to begin by 02Z.
Winds will become lighter as well with variable directions before
southeasterly resumes overnight. There is potential for another
round of activity tomorrow afternoon.
KBLH: Earlier storm activity has likely helped stabilize things
over/near KBLH to preclude new storm development the rest of the
afternoon and evening. A round of late night/morning showers is
possible but confidence of those occurring at the airfield too
low to reflect in the TAF. Anticipate light and variable winds to
become southerly overnight and continue through the day Wednesday.
As for sky cover, anticipate variable amounts of mid and high
clouds with bases AOA FL120.
A humid airmass will remain in place through the forecast period,
yielding elevated afternoon RH values and good overnight recovery.
Chances for wetting rains will continue for most areas almost
daily. Winds for the most part will remain light, with the
exception of thunderstorm outflows generating stronger gusts. The
fire danger threat is expected to remain low for the foreseeable
AZ...Flood Watch until 2 AM MST Wednesday for AZZ530>544-546-548>551-
Flood Watch until midnight MST tonight for AZZ545-547-552-
CA...Flood Watch until 2 AM PDT Wednesday for CAZ560>570.
AREA FORECAST DISCUSSION
National Weather Service Raleigh NC
950 PM EDT Tue Aug 9 2022
High pressure centered near Bermuda will extend westward across the
Southeast states through early Wednesday. A cold front will approach
from the northwest late Wednesday, then move slowly southeast
through North Carolina Wednesday night through Thursday night. A
secondary cold front will drop through the region late Friday. A
cooler and less humid air mass will build in from the north for the
.NEAR TERM /THROUGH TONIGHT/...
As of 950 PM Tuesday...
Strong slow moving thunderstorms produced pockets of 1 to 3 inches
of rainfall over the Triad, northern Sandhills, and the southern
Piedmont and have left a myriad of outflow boundaries across central
NC. One of which is draped over the Sandhills and is acting to focus
some shower/storm activity within a pocket of MLCAPE around 2000
J/kg and very little MLCIN which has avoided any convective
contamination so far this evening. RAP forecast and mesoanalysis
trends suggest deep moisture convergence over this area will slowly
weaken and increasing boundary layer stability will effectively cut
off precipitation chances within the next couple hours. As for
temperatures, persistence will rule the forecast as low-level
thicknesses will be comparable to the previous couple of mornings;
leading to lows in the upper 60s to low/mid 70s with urban areas
expected to remain the warmest.
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 251 PM Tuesday...
A broad upper-level trough centered across eastern Canada will begin
to dig southward into the Great Lakes region on Wednesday. Ahead of
the trough, a short-wave will extend down into central NC Wednesday
afternoon/evening. Associated weak mid-level height falls and
transiting vorticity perturbations will provide better upper-level
support for higher coverage in afternoon showers/storms compared to
recent days. High-res models continue to depict mountain convection
spilling eastward into western portions of our area early afternoon
supportive of likely POPs across our far northwest. Additional
convection will also focus along the Piedmont trough initially over
the Sandhills/Central Piedmont, and spread eastward through
Wednesday night. PWAT will be high again peaking near 2.0 inches,
supporting high CAPE ahead of the convection. However, models
continue to depict weak mid-level lapse rates and shear, which
should limit organization. Regardless, given some better upper-
support trickling in from the north, organized clusters may be
possible as the convection pushes east. Thus, isolated damaging wind
gusts could materialize within any stronger cells, but widespread
severe weather is not expected. Lastly, given the high PWAT and
slower storm motion, isolated flash flooding may be possible in or
near urban areas tomorrow afternoon/evening (especially across the
Triad where the WPC currently maintains a marginal risk for flash
flooding (level 1 of 4)). Otherwise, daytime highs will once again
peak in the lower to mid 90s, with overnight lows remaining warm in
the lower to mid 70s.
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 120 PM Tuesday...
Low pressure off the VA coast will drag a cold front across the area
on Thursday. Pre-frontal airmass characterized by PW`s around 1.75
inches, surface dewpoints in the 70s, and MLCAPEs around 500-1000
J/KG, will still be present across the area on Thursday, and showers
and thunderstorms should develop during the afternoon hours with a
focus mainly across the southern half of the forecast area. Guidance
pops still lingering in the 60-80 percent range during this period
and the updated forecast will remain near these values. While the
presence of a clearly defined forcing mechanism should result in
organized thunderstorm development, the lack of deep layer shear
(only 10-15kts) and extensive cloud cover should temper the severe
threat a bit.
Friday will see a secondary boundary cross the area from the
northwest, this one ushering in lower dewpoints and a clear trend
toward dry weather. By Friday afternoon, most locations should see
dewpoints in the upper 50s to lower 60s, the only exception being
across the southern Coastal Plain where the boundary may stall and
serve as the focus for a few showers and thunderstorms. Surface
ridging over the Ohio Valley should strengthen Friday night into
Saturday, move eastward into the Mid Atlantic, and effectively push
the front into SC on Saturday resulting in drier weather for the
weekend. Temperatures will still manage to rise into the lower 80s
(north) to upper 80s (south) but it will be noticeably more
comfortable this weekend. Similarly, low temps will also fall below
climatological normals with readings in the upper 50s (north) to mid
Broad northwesterly flow aloft will persist into early next week,
with a series of weak perturbations potentially moving across the
mountains into NC Monday and Tuesday. Varying ensemble solutions
aloft with some solutions indicating an upper low over the Great
Lakes while others bring a deeper low through the Tennesse Valley.
Cluster analysis tends to discount the TN low solution with odds
tilted more in favor of continued northwesterly flow and an upper
low over eastern Canada. This would result in a return to typical
summer weather with daily shower/storm chances within a Piedmont
trough propagating off the mountains and into central NC. PoPs in
the 20-30 percent range are consistent with today`s ensemble runs as
well as the latest NBM. Temps will increase a bit during this period
but still remain at or slightly below normal.
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
As of 804 PM Tuesday...
Convection is quickly fading/dissipating, with only some isolated
showers lingering across central NC. Remainder of the night will be
dry with predominately VFR conditions expected. The exception could
be some scattered/briefly broken MVFR ceilings INVOF KINT and KGSO
The approach of an upper trough and attendant lead surface cold
front from the NW will lead to higher coverage in showers and storms
compared to recent days. Periods of IFR to MVFr restrictions will be
possible with the stronger storms.
Light southwest winds of 5 to 10kts are expected through the TAF
period, with the potential for some occasional gustiness into the
teens at KRDU, KRWI, and KFAY Wednesday afternoon.
Outlook: Showers and storm chances increase again on
Thursday/Thursday night as a cold front pushes through the area.
Drier conditions are then expected Friday through Sunday.
Area Forecast Discussion
National Weather Service Springfield MO
607 PM CDT Tue Aug 9 2022
...Updated 00Z Aviation Discussion...
1. A isolated showers/storms remain possible tonight and early tomorrow
as a front over southern MO moves slowly south into AR and
stalls/weakens. Widespread rain isn`t expected, but still could
see isolated downpours.
2. May see some fog potential tonight with low level moisture and
a cooling boundary layer. Will monitor trends for possible fog
advisory late tonight.
3. Fairly quiet weather is then expect through the weekend with a
Canadian surface high center moving into the Great Lakes Friday-
Saturday. Temperatures will turn hotter again over the weekend but
with lower humidity.
.SHORT TERM...(This evening through Wednesday)
Issued at 300 PM CDT Tue Aug 9 2022
A weak frontal boundary dropped south to the vicinity of the
Missouri and Arkansas state line this afternoon. A few slow
moving showers/thunderstorms are still festering over south
central MO closer to a subtle upper level vort/low that shows up
in midlevel water vapor imagery. HRRR and some other short term
high res guidance show better chances for scattered convection
over our eastern counties into the evening hours. Progged
soundings show modest instability but still fairly robust pwats
close to 2.00 inches (from some guidance). Will need to watch for
isolated slow moving pulse storms and localized flooding.
Will start to see higher clouds clear from the northwest later
this evening setting up some fog potential with weak low level
winds and (finally) some soil moisture. Guidance varies on the
amount of overall clearing so will need to monitor trends. Better
chances would seem to be over the northern and eventually western
The weak sfc front will stall south of the area Wednesday. Some
lingering precip may be possible early in the day, but by
afternoon, progged showers look to push south of the southern MO
border. Clouds may linger, especially over our eastern counties.
Overall, it looks like a quiet, fairly pleasant day with highs in
the 80s, possibly touching 90 over the far western cwfa.
.LONG TERM...(Thursday through Tuesday)
Issued at 330 PM CDT Tue Aug 9 2022
Thursday: An upper ridge over the western U.S./Rockies will edge
east a bit as the upper low trough over southeast MO shifts east.
Midlevel height rises and a mostly clear sky are expected for
Thursday with a weak sfc ridge edging into the Midwest.
Friday-Monday: The upper flow pattern will remain little changed
with the western upper ridge moving east somewhat into the High
Plains. A sfc ridge will extend from high pressure over the Great
Lakes to the Ozarks pushing a comfortable air mass into the area
with lower dew points. A weak sfc low/trough will approach the
area late in the weekend veering winds a bit to the southwest with
temperatures likely to bump up well into the 90s over the western
cwfa, possibly touching 100F again over southeast KS and KJLN
area Sunday and Monday.
Tuesday: Consensus guidance breaks down the ridge somewhat by
Tuesday, but not confident to what degree. A signal for increased
chances for precip does exist by late Tuesday/Tuesday night into
the midweek period as the upper ridge retrogrades or becomes
established farther back to the west and impulses move southeast
through the region in northwest flow aloft. This would point to
cooler weather with some chances for showers/storms during the
midweek period. ECMWF ensemble members show a period of cooler
than normal temperatures by late next week.
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 607 PM CDT Tue Aug 9 2022
VFR conditions are expected for most of the TAF period, outside of
a low end chance for an isolated shower through the overnight
hours. Winds will remain light and variable through tonight.
Continuing to monitor fog potential across parts of the area
overnight. At this time, confidence remains too low to mention in
An isolated shower or thunderstorm remains possible at KBBG on
Wednesday morning, but coverage remains limited at this time.
Otherwise, a dry and quiet day can be expected.
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
740 PM EDT Tue Aug 9 2022
...New UPDATE, AVIATION...
Issued at 737 PM EDT Tue Aug 9 2022
Conditions have stabilized across West Central and SWFL after
earlier convection pushed through. Florida remains in the vicinity
of an inverted trough axis, which has continued to destabilize and
cool the mid-levels of the atmosphere, aiding vertical ascent
slightly and providing a boost to afternoon convection. Could
this perhaps allow a few more storms to develop late this evening?
It could. Some high-res guidance such as the HRRR continues to
hint at this possibility. The probability is rather low, though,
with so many factors to limit additional convection.
A few tweaks to the POPs have been made through the evening to
better account for current trends. Winds have also been tweaked
slightly to better capture conditions. Otherwise, the forecast
remains on track. Things are definitely looking much drier for the
next few days with more dust advecting over the state, greatly
suppressing thunderstorm development. No further significant
changes are anticipated before the overnight updates.
Issued at 405 PM EDT Tue Aug 9 2022
Surface high pressure ridge axis will remain north of Florida
through Wednesday then gets pushed south into the area Thursday
and then into the Florida Straits by the weekend as an upper level
trough and associated cold front move through the southeast
states. The east to southeast low level flow will continue
through Wednesday then become rather light Thursday and Friday,
and then north to northwest this weekend.
For the rest of today we`ll see scattered showers and
thunderstorms continue to move quickly northwest across the area
into early this evening. Skies will then become partly cloudy
later this evening and overnight.
Later tonight into Wednesday the dry Saharan Air Layer (SAL) will
move in from the southeast with precipitable water values still
forecast to fall below 1.5 inches across much of the area. This
will delay the convection until mid to late afternoon and evening
and also limit the overall coverage with rain chances 30 percent
or less. Highest chances should be along the west coast late in
the day where the sea breeze will be located.
For Thursday a rather light southeast to south flow will be in
place as the ridge axis shifts south across the area with the dry
SAL holding on for much of the day. Should see the sea breezes
develop and move well inland thanks to the rather light flow and
this along with the limited moisture could pop a few showers and
thunderstorms, but overall chances will remain 30 percent or
On Friday the weakening frontal boundary will move into north
Florida suppressing/splitting the ridge axis and thus allowing winds
to become light and variable. Deep moisture in the vicinity of
the boundary will drift south into the northern parts of the
area, but with the flow being rather light the highest rain
chances will be over the northern Nature Coast and interior.
On Saturday the low level west to northwest flow will setup and
with plenty of moisture in place we`ll see scattered to numerous
showers and thunderstorms develop with the best chances across the
Nature Coast and interior. However, with the flow being
westerly and the frontal boundary stalled out to the north we
could see convection at almost anytime across the Nature Coast,
while further south it will be mainly during the afternoon and
Early next week the upper level trough will remain over the eastern
U.S. with abundant moisture across the area leading to scattered to
Main hazards from the thunderstorms through the forecast period will
continue to be strong gusty winds, frequent lightning, and locally
heavy rainfall that could cause flooding of low lying and poor
drainage areas. Also, with the 500 mb temperatures remaining
around -7C to -8C over the next few days some hail cannot be ruled
out in the stronger storms.
Issued at 737 PM EDT Tue Aug 9 2022
Conditions have become quiet at area terminals with the atmosphere
now stabilizing after earlier storms. Some high-res models hint at a
few more storms overnight, but the probability is too low for
mention at this time, given how stable the atmosphere has become. A
similar story for tomorrow afternoon as well. While a couple
isolated storms could form in the 20-00Z time-frame, any impacts to
terminals are far too low for mention at this time. What is more
favorable is a few low clouds at terminals in the 10-14Z time-frame
with light ESE flow and cooler temps from earlier rain.
Issued at 405 PM EDT Tue Aug 9 2022
High pressure ridge axis will remain north of the area through
midweek producing moderate east to southeast wind flow over the
coastal waters with occasional nocturnal surges for increased seas
at times. Scattered showers and thunderstorms are expected mainly
during the late afternoon and nighttime hours with gusty outflow
winds and dangerous lightning, along with locally higher winds and
seas. High pressure sinks southward into the region later in the
week with lower winds and seas expected, but scattered showers and
thunderstorms will continue.
Issued at 405 PM EDT Tue Aug 9 2022
No fire weather hazards are expected through the week as minimum
relative humidity values will remain above critical levels and winds
will remain less than 15 mph outside of any convection.
.PRELIMINARY POINT TEMPS/POPS...
TPA 95 79 95 80 / 80 20 30 20
FMY 94 77 95 78 / 80 20 30 10
GIF 96 76 96 77 / 80 20 20 10
SRQ 93 75 93 77 / 80 20 30 10
BKV 94 74 95 74 / 70 20 20 20
SPG 93 79 93 81 / 80 20 30 20
PREVIOUS DISCUSSION/MARINE/FIRE WEATHER...Close
Area Forecast Discussion
National Weather Service Tulsa OK
933 PM CDT Tue Aug 9 2022
...New SHORT TERM...
(The rest of tonight)
Issued at 928 PM CDT Tue Aug 9 2022
Eastern OK and western AR largely sandwiched in between two areas
of convection this evening. One cluster over central OK, with
severe warned cell in Lincoln/Creek Co. Another larger cluster
focused over NC/NE AR. These occurring within old frontal
zone/moist axis and with modest low level jet developing tonight,
expect isolated to scattered showers and storms to eventually fill
in over about the southern 3/4 of the CWA overnight as suggested
by last several HRRR runs. Aside from some minor changes to POP
grids early in the period, remaining forecast in good shape.
(Tonight through Tuesday)
Issued at 111 PM CDT Tue Aug 9 2022
Modest low level jet will develop tonight with scattered storms
possible into Wednesday morning. Main precip area on Wednesday
will begin to focus further south as drier air begins to filter
into the region from the northeast.
Upper high currently over the Four Corners Region will begin to
shift east closer to the area with warm/humid conditions likely
through the weekend. High temperatures will again approach triple
digits early next week with excessive heat becoming more of a
concern. Overall rain chances through the extended periods will
likely remain low, however isolated storms possible Friday afternoon
across far southeast Oklahoma and across northwest Arkansas by
Tuesday of next week.
Issued at 609 PM CDT Tue Aug 9 2022
VFR conditions likely to persist into the early morning with very
low chance of any convective development this evening. Thereafter
isolated to scattered early morning convection appears possible.
Also patchy fog may develop across NW AR before sunrise. Overall
the coverage of showers and storms should be lesser tomorrow with
VFR conditions largely prevailing.
.PRELIMINARY POINT TEMPS/POPS...
TUL 73 93 69 93 / 20 10 0 0
FSM 74 92 74 94 / 50 40 10 20
MLC 72 93 71 93 / 30 20 10 10
BVO 70 93 65 94 / 10 0 0 0
FYV 69 89 65 90 / 40 30 10 10
BYV 70 87 66 90 / 40 30 10 10
MKO 71 89 70 91 / 30 20 0 10
MIO 70 91 64 93 / 20 10 0 0
F10 71 92 69 93 / 30 10 0 10
HHW 72 92 71 92 / 40 40 20 20