Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/22
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
927 PM MDT Mon Aug 1 2022
.UPDATE...
Update to expire the Flood Watch. Updated zone forecast is out.
24
&&
.PREV DISCUSSION...533 PM MDT Mon Aug 1 2022...
.AVIATION...
00Z TAF CYCLE
Scattered storm activity will continue to provide for a chance of
glancing or direct impacts from ts through ~03Z to 04Z this evening.
Outflow winds with gusts of 30-40kts, freq ltg, and localized heavy
rainfall will be the main hazard from any passing storm. The center
of the high is over west-central NM or east-central AZ, and this is
acting to suppress ts chances close to KGUP-KFMN. Storm chances also
relatively low near KROW, but cannot entirely rule out outflow winds
bringing gusts there from the north at some point this evening.
Otherwise, conditions clear overnight with lesser ts activity
expected Tuesday afternoon.
24
&&
.PREV DISCUSSION...329 PM MDT Mon Aug 1 2022...
.SYNOPSIS...
With high pressure over the forecast area, high temperatures will be
a few to several degrees above normal across most of northern and
central New Mexico Tuesday through Thursday. Tuesday will also
feature a downtick in thunderstorm coverage, but locally heavy
rainfall will continue to be possible. A moist backdoor front will
dive into the state Wednesday and Wednesday night enabling
thunderstorm coverage and rainfall intensity to increase both
Wednesday and Thursday. Temperatures will trend cooler Friday into
early next week as high pressure aloft shifts to the northeast of
New Mexico allowing better monsoon moisture to stream northward with
increased thunderstorm coverage mainly over central and western
areas.
&&
.DISCUSSION...
SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)...
Satellite imagery indicates the upper high center reorganizing over
eastern Arizona and western New Mexico this afternoon with
potentially some drier air aloft becoming entrained in the
circulation. Still, storms developed over the higher terrain as in
previous days and were moving erratically south of I-40 while
tracking to the southeast over north central and into northeast New
Mexico. Locally heavy rain continues to be possible with no changes
anticipated to the ongoing Flood Watch as storms this afternoon seem
to be focusing on or near active burn scars. The HRRR doesn`t seem
to latch onto much convection continuing beyond midnight while the
NAM12 keeps at least isolated activity going over the northwest
third to half of the CWA after midnight. Therefore kept widespread
but low pops going into the overnight. Little change expected for
Tuesday as storms again form over the higher terrain and move in a
southerly direction. Forecast highs over the eastern plains Tuesday
will warm to 100-102 from Tucumcari through Ft Sumner and Roswell
but not expecting a prolonged period of 100+ highs as was experienced
for a good part of July at Roswell.
99
LONG TERM...(WEDNESDAY THROUGH MONDAY)...
The 500 mb high pressure center will linger over the Four Corners on
Wednesday, when a moist backdoor front will move southwestward into
NM invigorating shower and thunderstorm coverage and rainfall
intensity along and east of the central mountain chain. Scattered to
isolated storms are forecast to return farther west, except for more
numerous activity over the southwest mountains where the best
moisture will exist. With the mid-level high pressure system still
in close proximity, high temperatures will vary from a few degrees
above normal over northwest areas to as much as 10 degrees above
normal over the southeast.
Look for an uptick in thunderstorm coverage and rainfall intensity
areawide on Thursday. Late Wednesday and Wednesday night the moist
backdoor front, probably aided by gusty thunderstorm outflow, will
push through gaps in the central mountain chain with a potentially
gusty east wind below canyons opening into the central valley
(especially around Albuquerque). The front will increase low level
moisture as it pushes westward to the continental divide Wednesday
night. Then, the mid-level high pressure center will begin to shift
eastward along the CO/NM border Thursday, allowing better monsoon
moisture northward over NM from Mexico. Models, particularly the GFS,
also depict a disturbance embedded in the periphery of the ridge
invigorating convection over southwest NM Thursday and Thursday
evening, while a moist low level return flow advances across the
forecast area from the southeast.
Friday through Monday the mid-level high pressure system will shift
further east of NM varying its center around the OK/KS border. This
will enable a fairly traditional stream of monsoon moisture to
continue crossing western and north central NM out of Mexico, with
embedded disturbances at times, enabling daily rounds of scattered to
numerous showers and thunderstorms to continue favoring central and
western areas. Temperatures will also cool below normal with all the
moisture in place, except for the far eastern plains where readings
should be a few degrees above normal each day.
44
&&
.FIRE WEATHER...
Locally heavy rain associated with slow moving thunderstorms will
continue for the foreseeable future. There may be an uptick in
showers and storms Thursday into Friday. The upper high center will
wobble over the region, then drift back to the east late this week,
only to return back over the central and southern Rockies by the
middle of next week. Cell motion through tonight will be slower and
erratic south of I-40 and to the southeast over northern New Mexico.
High temperatures through Saturday won`t stray too far from normal.
Areas of fair to poor ventilation are forecast each day, but may be
more widespread Friday and Saturday.
99
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
853 PM CDT Mon Aug 1 2022
.UPDATE...
Issued at 841 PM CDT Mon Aug 1 2022
Subtle/weak shortwave energy noted on water vapor imagery moving
across the Dakotas at this time, and interesting to notice some of
the circulation in the various upper level smoke imagery. Have
seen an increase in shower/thundershower activity over the past
hour or so across north central SD in response to this. Have
adjusted POPs over the next several hours based on radar trends.
There is at least some potential for this activity to sustain
itself as it moves eastward across the CWA, given the increasing
instability and shear over the next several hours, as well as the
development of a low-level jet. Limiting factors seem to be rather
dryish looking soundings as well as the overall weakness of the
passing disturbance. Will watch trends and continue to update the
POPs as needed.
&&
.SHORT TERM...(This Evening through Tuesday Night)
Issued at 156 PM CDT Mon Aug 1 2022
There is a slight chance for some showers in Corson county this
evening depending on if a surface trough and push of moisture
combine in western SD.
Tomorrow has the best chance for storms during the short term period
as first a warm front then cold front pass over the region, although
they aren`t very good chances. As the warm front passes, Tuesday
morning, the atmosphere is capped, but as we go through the
afternoon and continue to heat, that will possibly erode but most
model soundings show it won`t. Between the fronts there is a chance
for some precipitation so left the pops where they are, but
deterministic models are keeping the low levels dry. The moisture
resides above 600 mb so most of the precip that does fall will
probably evaporate before it hits the ground. There is still a
chance for some light showers with limited thunder potential. MLCAPE
values at during this time (18Z Tue through 00Z Wed) range from 1000
to 2000 J/kg with bulk shear between 35 and 45 kts. The NAM shows
bulk shear values above 50 kts over northeastern SD by Tuesday
evening. Model soundings show an inverted V reaching up past 600 mb
suggesting winds could be a threat. If storms do form, there is a
small chance that some could produce strong to severe winds.
Above average temperatures return Tuesday with highs in the 90s to
low 100s. The HRRR suggests that smoke could drift into the area
from fires to the west and keep high temperatures a little lower
than previously forecasted. After the cold front moves through
Tuesday evening, RH values west of the James River are expected to
drop close to or below 20 percent but with marginal winds, will bump
the red flag warning decision to the night shift.
.LONG TERM...(Wednesday through Monday)
Issued at 156 PM CDT Mon Aug 1 2022
High pressure settles in as the extended opens on Wednesday with a
building upper ridge. Since that ridge will still be in the process
of translating east over the Dakotas, temperatures will be the
coolest of the period across the east with highs only in the lower
80s. By Thursday, highs will once again be back above normal, helped
by sfc return flow behind the exiting area of high pressure. Breezy
and mostly dry conditions are expected through Friday. Low pressure
will move through Friday night and could bring some showers and
thunderstorms mainly after any daytime capping breaks Friday evening
and into Saturday morning. The weekend may remain more unsettled and
be a bit cooler, but models differ on timing of systems that far out
in the extended. For now, it appears there might be a break in
precip chances on Sunday before more showers become possible Sunday
night into Monday morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 639 PM CDT Mon Aug 1 2022
Terminals KABR,KATY,KPIR,KMBG
VFR conditions are forecast to prevail through the TAF period. A
few sprinkles or very light showers are trying to develop over
central SD this evening, which may affect portions of the region
this evening/overnight in a very isolated manner. These showers
would be high-based with little in the way of precip, along with
maintaining VFR conditions. Included VCSH mention in the TAFs.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...TMT
SHORT TERM...KK
LONG TERM...Wise
AVIATION...TMT
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1034 PM EDT Mon Aug 1 2022
.SYNOPSIS...
An approaching cold front will bring increasing clouds
with a chance for some showers and a few thunderstorms overnight and
Tuesday. Drier but warm weather returns Wednesday. Then, hot and humid
conditions are expected Thursday. A cold front will bring chances for
showers and thunderstorms Thursday and Friday with some locally heavy
rainfall.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Update as of 1030 PM EDT...Temps continue to cool off into the
60s and 70s with Old Forge down to 60F this hour in the southern
Adirondacks, and Claryville in the eastern Catskills. Some mid
and high clouds are beginning to move from western and central
NY into Adirondacks and western Mohawk Valley which will slow
the rate of fall of temps. A band of showers and scattered
thunderstorms is moving towards western NY and another batch of
showers is moving towards eastern Lake Ontario and the Tug Hill
Plateau based on the regional radar mosaic.
A mid and upper level trough continues to approach from
southeast Canada and the Great Lakes Region. A prefrontal trough
ahead of the sfc wave and cold front will bring a few showers
and isolated thunderstorms around midnight into the early
morning hours over the western Adirondacks/western Mohawk Valley
based on the latest CAMS. Some slight timing adjustments with
this update. Small amounts of elevated instability are present
based on the RAP meso-analysis over the southern Adirondacks. We
tried to keep the thunder threat mostly here. Some patchy mist
and low stratus may also form over Litchfield County into the
Berkshires and also south of I-84 due to clear skies and
light/calm winds. We did include patchy mist into the southern
most zones (southern Dutchess and Litchfield Counties).
Dew points slowly inch up into the mid to upper 60s by 12z
tomorrow due to light south/southeast winds. Therefore, it will
be a warmer and a slightly muggier night with overnight lows
only dropping into the mid to upper 60s with upper 50s to lower
60s over the higher terrain. We did lower mins into the mid 50s
over the southern Dacks.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Tomorrow, a cold frontal boundary will track through our region.
The front and associated wind shift boundary will make it to the
Hudson River Valley mid-morning tomorrow, and will then progress
southeastwards into western New England and through the Mid
Hudson Valley during the early afternoon hours. There could be
some showers and thunderstorms with this cold frontal passage,
although the severe threat looks to be on the low side tomorrow.
As has been the trend so far this summer, the late morning
frontal passage will limit the best instability to areas south
and east of the Capital District. HREF ensemble mean is showing
SBCAPE values climbing to around 1000 J/kg by late morning
tomorrow ahead of the front. However, low-level for ascent will
be fairly weak due to weak low-level convergence and a weak
temperature gradient across the front. Furthermore, abundant
mid-level dry air may also inhibit convective initiation, while
lack of deep-layer shear will prevent any convection that does
initiate from becoming well-organized. Heights aloft actually
rise during the day tomorrow, and mid- level lapse rates are
already poor, which further suggests a minimal threat for severe
weather. The SPC has areas east of the Hudson River in a general
thunder risk tomorrow, which seems appropriate given the setup.
Chances for showers and storm diminish from northwest to
southeast behind the frontal passage tomorrow afternoon through
the evening. Daytime highs will range from the low 70s across
the Adirondacks to upper 80s for valley areas south and east of
the Capital District.
Tomorrow night, precip chances end during the evening as high
pressure builds in from the west and heights aloft continue to
rise. Clouds will diminish through the night, and winds become
light to calm. This will set the stage for favorable radiative
cooling conditions, so overnight lows will be cooler than the
previous night with low/mid 60s for the Hudson Valley and mid to
upper 50s elsewhere. Some patchy fog is also possible in the
typical locations as well as for areas that receive rainfall
during the day Tuesday.
Wednesday looks like another dry and tranquil weather day with
a 1018 mb surface high in control to start the day. However, the
surface anticyclone slides to our east by Wednesday afternoon,
and winds become more southwesterly into our region around the
periphery of the high. This will help advect warmer air into the
region. Highs will likely top out in the upper 80s to around 90
for valley areas. With southwesterly downsloping from the
Catskills, a few areas locally in the Capital District may see
temperatures in the low 90s.
Wednesday night, warm, moist air continues to be advected into
our region as a warm front lifts northwards. Most sources of
guidance show a weak upper impulse embedded in zonal flow aloft
tracking eastward across our region Wednesday night, but the NAM
is the only one that shows any kind of appreciable convection
with this feature. With low-level moisture lacking, will tend to
side against the NAM and will just keep most areas dry with just
a slight chance for a shower or thunderstorm across the
Adirondacks. Otherwise, it will become noticeably more humid
overnight, with lows only expected to drop into the mid to upper
60s for most places.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
The extended period opens with a very hot and humid air mass over
region with possible record temps. A cold front will bring showers
and thunderstorms Thursday into Friday. However, the boundary may
move back north, as a warm front on Saturday with more chances of
showers and thunderstorms. High pressure builds in from the south
Sunday with more heat and humidity with diurnally driven isolated-
scattered showers and thunderstorms. Another cold front increases
the chances for showers and thunderstorms to open the week.
Thu...Mid and upper level riding builds along the East Coast due to
an extension of the Bermuda High. The latest NAEFS guidance
continues to depict anomalous 850 hPa temps +2 to +3 STDEVs above
normal. The actual temps at 850 hPa rise to about +19C to +22C from
northwest to southeast based on the latest 12Z GFS/ECMWF. Record
highs could be reached in the upper 90s and close to 100F in
portions of the Hudson Valley and also across the forecast area. The
boundary layer south to southwest flow may help with some
downsloping in the Capital District/Hudson River Valley. The record
high for Albany on Aug 4th is 98F set in 1955. The caveat that
could limit record temps is an approaching cold front and a
prefrontal disturbance. Scattered showers and thunderstorms with
associated cloud cover will likely increase north and west of the
Capital Region in the late morning into the afternoon. Heat
headlines (at least Heat Advisories) will likely be needed below
1000 ft in elevation with widespread heat indices/apparent temps in
the mid 90s to lower 100s. A few locations could get close to
excessive heat warning with dewpoints in the 60s to lower 70s. A few
thunderstorms could be on the stronger side but the amount of 0-6 km
shear being 15-25 kts and low to moderate amounts of instability may
limit a widespread possible threat. This will continue to be
monitored. PWATs increase to +1 to +2 STDEVs above normal, so some
locally heavy downpours will be possible. Highs temps will be in
the upper 70s to upper 80s over the mtns with lower to upper 90s in
the valleys (a few 100F readings possible in the mid Hudson Valley).
Thu night...The prefrontal trough and cold front continue to move
towards the region with scattered showers and thunderstorms
diminishing to isolated to scattered showers with less instability.
It will be a muggy night with lows in the 60s to lower 70s.
Fri-Fri night...The medium range guidance/ensembles has continued to
slow down the frontal passage from north to south across the region.
The downstream ridging over the western Atlantic is slowing down the
progress of the front. A chance of showers and thunderstorms for
the entire area, but cloud cover may limit heating and convective
development more from the Capital Region north and west. We will
have to monitor for a few stronger storms with locally heavy rain
from the Capital Region south and east. WPC in the Day 5
experimental excessive rainfall outlook has most of western New
England and from Albany south and east in a Slight Risk. Heat
indices may get close or into the mid 90s from the mid Hudson
Valley south and east. We will mention this possibility in the
HWO. Max temps are not expected as hot on Friday with mid 70s to
mid 80s north and west of the Capital Region, and mid to upper
80s from the Capital Region south and east. The showers and
thunderstorms decrease Fri night with the front settling south
of the region. A weak wave moving along it may prolong the
showers some south of I-90. Lows will be in the 60s with some
upper 50s over the southern Adirondacks, southern Greens and
eastern Catskills.
Sat-Sat night...The frontal boundary initially stalls and then
starts to lift back north/northwest as a warm front, as once again
the Bermuda high builds in from the western Atlantic. Slight to low
chances of showers increase during the afternoon, as well as
isolated thunderstorms. It will become more humid with dewpoints in
the 60s to around 70F. Highs will reach the mid and upper 80s in
the valleys, and upper 70s to lower 80s over the higher terrain. The
showers and isolated thunderstorms should diminish Sat night with
lows mainly in the lower 60s to around 70F.
Sun-Mon...The mid and upper level flow becomes zonal late in the
weekend into early next week. It is difficult to find a clear
trigger mechanism for focusing convection on Sunday. However, with
the heat and humidity diurnally driven convection or differential
heating between the mtn/valleys may focus scattered showers and
isolated thunderstorms. A cold front and a short-wave trough
approach from the west to open the week with a chance of showers and
isolated thunderstorms. Temps continue to run above normal with
highs in the upper 80s to lower 90s in the lower elevations each day
and mid 70s to mid 80s over the higher terrain. Humidity levels
will also be high and will have to monitor for marginal heat
advisories in the valleys with dewpoints in the 60s to around 70F
and heat indices close to the mid 90s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Through 00Z WED...An upper level trough and a cold front will be
approaching from the west tonight and cross the region tomorrow.
VFR conditions are expected early this evening for
KGFL/KALB/KPOU/KPSF with few-sct cumulus and scattered cirrus.
South/southeast low-level flow and sfc dewpoints creeping up
with allow for some patchy fog and low stratus to potentially
impact KPOU/KPSF. We introduced a TEMPO for MVFR stratus at KPSF
between 03Z-06Z/TUE and we also brought MVFR cigs/vsbys at KPOU
around 07Z/TUE. Cigs were forecast broken-overcast at 1.5-2.5
kft AGL with vsbys around 5SM. We were less confident for IFR
stratus at KPSF and only brought a scattered layer. Further to
the north, mid and high clouds will increase ahead of a
prefrontal trough for KGFL/KALB.
The lower stratus and patchy mist should decrease around
12Z/TUE for KPOU/KPSF. The cold front will bring isolated to
scattered showers and a few thunderstorms in the late morning
into the afternoon. We started a VCSH group at KGFl at 13Z,
KALB/KPSF at 15Z. We used PROB30 groups at KGFL/KALB for showers
between 17Z-21Z/TUE with MVFR vsbys/low VFR cigs. If confidence
increases for higher probabilities of thunderstorms, then they
will need to be added to later TAFs here. We did include a
PROB30 for a thunderstorm and MVFR conditions at KPSF between
17Z- 21Z/TUE. For KPOU we kept VFR with sct cumulus and
scattered to bkn cirrus with better forcing to the north.
South to southeast winds of 4-8 kt for KGFL/KALB tonight with
the winds becoming light and variable to calm at KPOU/KPSF. The
winds will increase from the south to southwest at around 10 kts
in the late morning into the afternoon. The winds will veer to
the west to northwest after 21Z at 8-12 kt with a few gusts
around 16-18 kt at KALB/KPSF.
Outlook...
Tuesday Night: No Operational Impact. NO SIG WX.
Wednesday: No Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: Moderate Operational Impact. Chance of SHRA...TSRA.
Thursday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Friday: Moderate Operational Impact. Likely SHRA...TSRA.
Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Saturday: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.FIRE WEATHER...
Dry weather continues through this evening, but a weak cold
front will approach from the west later tonight, bringing a
chance for a few showers and possibly a thunderstorm late
tonight. There is a chance for showers and thunderstorms across
the region tomorrow, but dry weather returns tomorrow evening
through tomorrow at least Wednesday evening.
Minimum RH values are in the 45 to 65 percent range this
afternoon, but will recover to 90 to 100 percent tonight.
Minimum RH values are expected to be in the 50 to 65 percent
range Tuesday afternoon with scattered showers and isolated
thunderstorms. RH values once again recover to at least 90
percent Tuesday night.
Winds will be light and variable but mainly southerly at 5 to
10 mph today and tonight. Winds shift to west and northwest
Tuesday, with some gusts up to 20 mph during the afternoon.
Winds become light and variable tomorrow night after sunset.
&&
.HYDROLOGY...
Rainfall will be light and spotty across the area through the
middle of this week. A cold front could bring scattered showers
and thunderstorms late tonight and Tuesday, however most areas
will not receive significant amounts of rain. This will continue
to allow for rivers and streams to hold fairly steady. Many
areas from the Hudson Valley eastward are now in the D0
(Abnormally Dry) to D1 (Moderate Drought) categories in the
latest US Drought Monitor.
The best upcoming chance for some scattered showers and
thunderstorms may be on Thursday with an approaching frontal
system. Any showers or thunderstorms on Thursday afternoon or
evening could contain some locally heavy downpours.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...Main/Wasula
NEAR TERM...Main/Wasula
SHORT TERM...Main
LONG TERM...Wasula
AVIATION...Wasula
FIRE WEATHER...Main/NAS
HYDROLOGY...Main/NAS
Area Forecast Discussion
National Weather Service Boston/Norton MA
1039 PM EDT Mon Aug 1 2022
.SYNOPSIS...
Becoming hot, muggy, with brief widely scattered showers and
isolated thunderstorms develop ahead of an approaching cold
front Tuesday afternoon. Dry and very warm again Wednesday
albeit noticeably cooler along portions of the immediate coast.
This will be followed by near record high temps and oppressive
humidity Thursday some of which may linger into Friday. The
threat for scattered showers and thunderstorms increases Friday
and may persist at times this weekend into next Monday, but a
washout is not expected. Above normal temperatures continue as
well, but not at the potential record breaking levels of
Thursday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
No major changes to the forecast this evening. Looks like the
last of the showers finally moved offshore from the Cape this
evening. Otherwise, will just be dealing with stratus across
southeast MA, RI and portions of northeast CT. Expecting these
clouds to finally start to dissipate after daybreak Tuesday.
745 PM Update...
Weak surface wave south of Nantucket was in the process of
departing the region. This was taking the last of the lingering
light showers across the Cape/Islands out to sea. Dry weather
will persist overnight. In the wake of the departing weak low
pressure system...surface winds will shift to the southwest
keeping bulk of the low clouds across RI/SE MA from advancing
much further north overnight. In fact...may it see improvement
towards daybreak in these locations. It will remain muggy
tonight, which may lead to localized patchy ground fog in the
typically prone locations late. Lows will mainly in the 60s to
near 70.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Highlights...
* Becoming hot, muggy, with some scattered garden variety t`storms
ahead of an approaching cold front.
A surface low over the northern Great Lakes region moves northeast
into the Saint Lawrence River Valley. Out a head of the trailing
cold front southwest winds are 8-12 kt with gust to 15-18 kt near
the immediate coast. Temperatures throughout the day reach 88-92
degrees with an apparent temperature of 92-95 degrees. Dew points
are back in the low 70s for the most part and upper 60s across the
northern border. There will be some cooler spots, coast and east
slopes of the Berkshires, there temperatures are in the low to mid
80s. A cold front moves across the region between 18z and 02z with
isolated thunderstorms possible.
Forecast soundings off the HRRR show plenty of instability with on
average 1500 J/kg of MUCAPE, but next to no shear. We have healthy
surface to 3km lapse rates of 8.0C/km, but as always the mid level
lapse rates are less than ideal, around 5.5C/km. At this time SPC
has much of the region in general thunder for Tuesday afternoon,
primarily looking at garden variety storms with a low chance for an
isolated strong or severe storm. PWATs are 1.5 inches which is near
normal for early August, so a few heavier downpours aren`t out of
the question. We need the rain, though it will be isolated. In
addition, localized strong wind gusts are a possibility tomorrow as
well given DCAPE values are around 1000.
Post cold front wind direction becomes west/northwest which will
temporarily help dry out the atmosphere and reduce dew points to the
low 60s. Temperatures though will remain mild with lows in the mid
and upper 60s to low 70s at the urban centers.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights...
* Dry & Very Warm Wed but noticeably cooler along the coast
* Near Record High Temps Thu between 96-101 Degrees along with Heat
Indices in the 100 to 104 degree range
* Heat & Humidity linger Fri with scattered showers/t-storms possible
* Still above normal temps this weekend into Mon but not record
breaking; with the risk for a few showers/t-storms at times
Details...
Wednesday...
A somewhat drier and a bit less humid airmass will be ushered into
the region behind Tuesday/s cold frontal passage; but it still will
be quite warm away form the immediate coast. A weak ridge of high
pressure will provide plenty of sunshine and dry weather. We still
expect high temps to top out in the upper 80s to near 90 in many
locations. The weak pressure gradient will allow for sea breeze
development and noticeably cooler high temps along portions of the
immediate coast; compared to Tuesday.
Wednesday night...
The weak ridge of high pressure moves east of the region Wed night.
Dry weather will persist given the lack of any real synoptic scale
forcing. Low temperatures will mainly be in the 60s.
Thursday...
All the guidance is in very good agreement in pumping a very
anomalous airmass into southern New England. 850T are depicted to
rise to between +21/+22C across most of the region. Good mixing with
plenty of sunshine should support near record high temps in the 96
to 101 degree range across much of the region. Oppressive heat
indices of 100 to 105 degrees are expected and Heat Advisories will
be needed for many locations. Low risk for approaching Excessive
Heat Criteria, but thinking is dewpoints will not be quite high
enough. Temps will be a few degrees lower towards the south coast
with a modified marine airmass, but still hot. The lack of synoptic
scale forcing/deep layer moisture will result in mainly dry weather
on Thu. However, we can not rule out a few showers/t-storms working
into our western zones late Thu/Thu night.
Friday...
The actual surface cold front will cross the region sometime on
Friday. The latest guidance seems to have trended with a slower cold
frontal passage on Friday, so a decent shot much of the region see/s
high temps break 90 again. In fact, dewpoints may pool in the 70 to
75 degree range. So even though temps may be several degrees lower
than Thursday; Heat Indices of 95 to 100 degrees are certainly
possible particularly for southern areas. Decent shot Heat Headlines
will need to be continued into Fri. Would not be surprised if these
numbers even have to be increased too with later forecast packages
if this front continues to slowdown.
The other issue on Friday will be scattered showers and
thunderstorms with the actual cold front. Localized heavy rainfall
will be possible too given relatively weak wind fields and Pwats of
2+ inches.
This Weekend into Monday...
The EPS/GEFS guidance continue to indicate above normal height
fields across the region. This will favor above normal temps
persisting, but not to the levels we are expecting on Thu. But we
certainly may see high temps in the 90+ degree range at times. There
also will be the risk for a few showers/t-storms with a frontal
boundary/shortwave or two, but not a washout. Timing is quite
uncertain at this point, but guidance tends to be favoring Sat and
Mon as a better chance for the activity at this point.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Tonight...Moderate confidence.
MVFR-IFR conditions, mainly from low clouds, will generally
remain across RI/SE MA tonight. Light SE-S winds will shift to
the SW, which should keep the low clouds from advancing much
further northwest than their current location. Otherwise, expect
VFR conditions outside some localized fog patches.
Tuesday...High confidence.
Mainly VFR conditions with a scattered to broken deck of diurnal
CU. Widely scattered brief showers and perhaps a few isolated
t-storms develop in the afternoon, which may result in
brief/localized lower conditions but areal coverage/duration
should be limited. SW winds 10-15 knots.
Tuesday Night...High confidence.
VFR. NW wind 5-8 kt.
KBOS...Moderate confidence in TAF.
KBDL...High confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday through Wednesday Night: VFR.
Thursday: VFR. Breezy.
Thursday Night: VFR. Breezy. Slight chance SHRA, isolated TSRA.
Friday: VFR. Chance SHRA, chance TSRA.
Friday Night: Mainly VFR, with local IFR possible. Chance SHRA,
chance TSRA.
Saturday: Mainly VFR, with local IFR possible. Breezy. Chance
SHRA, slight chance TSRA.
&&
.MARINE...
Forecaster Confidence Levels:
Low - less than 30 percent.
Medium - 30 to 60 percent.
High - greater than 60 percent.
Monday evening into Tuesday night...High confidence.
Surface low pressure moves over coastal waters tonight with
chance showers and low stratus clouds. Poor vsbys conditions
develop overnight into the early hours of Tuesday. Short wave
provides a secondary chance for showers for the waters south of
Block Island to Nantucket. Vsbys improve during the day with SW
wind 10-15 kt and near shore gust to 20 kt. Seas generally 2 to
4 feet. Cold front brings chance showers and slight chance
thunder Tuesday afternoon and early evening. Post cold front
wind direction becomes northwest at 8-12 kt.
Outlook /Wednesday through Saturday/...
Wednesday through Thursday: Winds less than 25 kt.
Thursday Night: Winds less than 25 kt. Areas of seas
approaching 5 ft. Slight chance of rain showers, isolated
thunderstorms.
Friday: Winds less than 25 kt. Seas locally approaching 5 ft.
Chance of rain showers, chance of thunderstorms.
Friday Night: Winds less than 25 kt. Chance of rain showers,
chance of thunderstorms.
Saturday: Winds less than 25 kt. Slight chance of rain showers,
isolated thunderstorms.
&&
.CLIMATE...
August 4th daily record maximum high temperature.
BOS - 96F [1928]
ORH - 95F [1944]
PVD - 98F [1944]
BDL - 96F [1944]
August 4th daily record maximum low temperature.
BOS - 76F [1930]
ORH - 72F [2002]
PVD - 74F [2010]
BDL - 74F [2006]
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...None.
&&
$$
SYNOPSIS...Frank/Gaucher
NEAR TERM...Belk/Frank
SHORT TERM...Gaucher
LONG TERM...Frank
AVIATION...Belk/Frank/Gaucher
MARINE...Frank/Gaucher
CLIMATE...Staff
Area Forecast Discussion
National Weather Service Billings MT
839 PM MDT Mon Aug 1 2022
.UPDATE...
Heat Advisory: Have cancelled as temps are cooling this evening.
That being said, with a little downslope wind and increasing cloud
cover from the west, it will be a mild night across the area.
Some locations will stay above 70F.
Red Flag Warning: Have cancelled the southern tier due to the
cooler temps and rising humidities this evening. Northern fire wx
zones will see breezy winds and continued dry conditions tomorrow,
so the RFW looks good for Tuesday.
Could be some light showers or sprinkles mainly across our west
tonight as we see a gradual increase in mid/upper level moisture.
Forcing and instability are lacking though, and the boundary layer
is obviously quite dry, so don`t get your hopes up for actual
precipitation. Shortwave over BC/WA will pass to our north over
the next 18-24 hours, while monsoonal wave currently lifting thru
NV will turn eastward thru WY tomorrow. The latter energy will
bring some showers/t-storms to our south on Tuesday, while our
north (and a good amount of the cwa) remains dry. Billings may or
may not see an isolated shower.
JKL
&&
.DISCUSSION...
Tonight through Tuesday night...
Early this afternoon temperatures are already in the mid to upper
90s with a few locations having hit 100 degrees. This all looks
good for the Heat Advisory, with HeatRisk still showing high
category. Humidity has already dropped into the teens and even a
few single digits. Winds have been 15 to 20 mph with gusts into
the 30s. With these conditions, the Red Flag Warning looks in good
shape.
Starting to see some CU popping over the southwestern mountains as
a little monsoonal moisture moves up into the area. With a little
shortwave energy moving into the area, along with a weak cold
front that will move across the area tonight, still cannot rule
out a high-based thunderstorm over the western zones.
Tomorrow will be generally cooler behind the cold front. There
will also be more monsoonal moisture moving into the southwest. This
will help keep humidity dropping much farther than upper teens.
However, winds along the northern tier of counties, from Wheatland
County to Custer County, will see winds increasing again tomorrow
afternoon, to similar conditions. With the humidity still
dropping into the teens and the wind gusting upwards of 30 mph,
have extended the Red Flag Warning for the northern tier. Farther
south will see a better chance for shower and thunderstorms,
mostly over the mountains, but some may move off into the adjacent
foothills and plains. With the better moisture from the monsoon,
some of these storms could produce some localized heavier rain.
With winds being more out of the west, there could be some smoke
starting to move into the area. The HRRR does not show significant
widespread smoke at the surface, but there will be some more
localized areas of smoke. Reimer
Wednesday through Monday...
High pressure over the region Wednesday and Thursday will bring
mainly dry and hot conditions. Temperatures will warm from the
upper 80s to 90s on Wednesday, to 95-105 degrees on Thursday. By
Friday, a shortwave and associated cold front, along with
monsoonal moisture working into the region look to bring a return
of shower and thunderstorm chances. Thunderstorms will be more wet
than dry with PWATs approaching an inch. Additional thunderstorm
chances look to continue through the weekend. Temperatures will
cool into the weekend with forecast highs on Friday in the upper
80s to 90s, dropping into the 80s for Saturday. Upper 80s to 90s
return Sunday and Monday. STP
&&
.AVIATION...
VFR conditions will prevail through Tuesday. However, some
reductions in slantwise visibility due to area wildfire smoke are
possible. A few showers will occur over the Crazy, Beartooth and
Absaroka mountains with some local mountain obscurations this
evening. W to NW winds will increase again Tue. with gusts of 25
to 35 kt. A cold front will move S into the area Tue. afternoon
with a shift to NW winds. Expect scattered showers over and near
the southern mountains Tue. morning, with increasing chances for
thunderstorms in the afternoon. Localized MVFR or lower conditions
are possible in the thunderstorms. Arthur
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 072/093 062/095 065/099 067/091 062/086 061/092 065/095
12/T 10/U 10/U 24/T 43/W 22/W 22/W
LVM 063/090 053/093 058/095 058/089 053/087 052/091 056/094
22/T 10/U 11/U 35/T 44/T 22/W 22/W
HDN 067/095 057/096 060/101 063/093 059/088 058/094 061/097
01/E 10/U 10/G 22/W 42/W 31/U 22/W
MLS 067/098 061/094 064/102 069/094 063/085 061/091 065/094
01/N 10/U 10/G 11/B 32/W 31/U 21/U
4BQ 066/095 061/093 064/099 068/096 064/086 063/091 065/093
02/T 10/U 10/U 11/B 42/W 32/W 22/W
BHK 063/095 060/089 063/099 068/093 061/082 059/088 062/091
01/E 10/U 10/U 11/B 42/W 32/W 21/U
SHR 063/091 059/091 061/098 064/093 059/087 057/091 060/093
03/T 31/U 10/U 12/T 53/T 32/T 22/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Red Flag Warning in effect until 9 PM MDT Tuesday FOR ZONES
117-124-127-128-130-132.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Corpus Christi TX
538 PM CDT Mon Aug 1 2022
.AVIATION /00z TAFs/...
VFR conditions expected through the overnight hours at all sites.
MVFR CIGs will be possible, briefly, Tuesday AM across eastern
terminals. Gusty winds out of the S-SE will continue tonight,
weakening during the overnight hours. Winds will increase once
again Tuesday afternoon, with gusts to around 25 knots possible
for all terminals.
&&
.PREV DISCUSSION... /Issued 358 PM CDT Mon Aug 1 2022/
SHORT TERM (Tonight through Tuesday Night)...
The summertime heat continues.
The heat combined with humid conditions Tuesday afternoon will
result in heat indices of 105 to 109 across S TX. Some locations
could briefly reach 110 and will have to monitor for possible Heat
Advisory for Tuesday.
Elevated fire weather conditions will be possible Tuesday afternoon
and evening across the Brush Country due to RH values between 20-30
percent and gusty S to SE winds.
As for rain chances, isolated showers or thunderstorms remain
possible this afternoon along the sea breeze as it moves west. The
Total Precipitable Water satellite imagery shows 2 inch PWATs across
the Coastal Counties and over the coastal waters. However, the
convection is struggling to develop due to a weak capping inversion,
which should keep the convection isolated. Rain chances are expected
to wane this evening and overnight. As a mid/upper level inverted
trough tracks farther west away from S TX and high pressure builds
across S TX, PWATs are progged to lower to around 1.5 inches by
Tuesday. With the high pressure bringing drier conditions across S
TX, rain chances will be even lower for Tuesday, but can not rule
out a few rogue showers. Several models show a few weak showers
toward early Tue morning across the waters. The HRRR is the most
aggressive with scattered stronger showers or thunderstorms
across the marine zones for Tue. For now, only went with a slight
chance of convection across the marine areas and 5-10 silent PoPs
across land areas.
LONG TERM (Wednesday through Monday)...
The upper level high pressure ridge will continue to build over the region
Wednesday/Thursday. Deterministic output predicts a region of copious
moisture to move southwestward into the CWA Friday and increase the chance
for convection. An apparent TUTT low is predicted to enter the western
Gulf of Mexico Friday, with the axis over the CWA/adjacent Waters Friday night/
Saturday morning. Expect convection to develop over the region Saturday
afternoon/evening as this TUTT low moves west of the region. Heat Advisory
conditions possible over portions of the CWA Wednesday/Thursday. Maximum Heat
Index values 105-109F expected Friday/Saturday. Elevated fire weather conditions
anticipated Wednesday/Thursday over the Brush country/Rio Grande Plains.
MARINE...
A moderate onshore flow can be expected tonight. The flow will then
become weak to moderate by Tuesday morning, then restrengthen
Tuesday afternoon to moderate levels. Isolated showers and
thunderstorms are possible Tuesday morning. Copious moisture may
result in isolated/scattered convection Friday over the Waters.
Anticipate a TUTT low to move west of the Waters and contribute to
convection Saturday over the Waters. Otherwise, weak to moderate
onshore flow expected during the period.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 79 95 80 96 79 / 10 10 0 0 0
Victoria 77 97 77 96 78 / 0 10 0 0 0
Laredo 79 106 80 107 79 / 10 10 0 0 0
Alice 76 102 76 103 77 / 0 10 0 0 0
Rockport 82 94 83 94 83 / 10 10 0 0 0
Cotulla 79 106 77 109 79 / 0 0 0 0 0
Kingsville 77 99 78 99 78 / 0 10 0 0 0
Navy Corpus 82 92 83 91 83 / 10 10 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
HA/72...AVIATION
Area Forecast Discussion
National Weather Service Peachtree City GA
908 PM EDT Mon Aug 1 2022
.UPDATE...
Thunderstorms are ongoing in portions of west-central Georgia, to
the south of the differential heating boundary, but are expected
to weaken and diminish in coverage over the next couple of hours
with the loss of daytime heating. Showers to the north of the
boundary are similarly diminishing. PoPs have been adjusted to
reflect these trends. Portions of west-central Georgia, near
Columbus, received heavy rainfall over the last 2-3 hours,
although rainfall rates have dropped as stratiform rain moves over
that area, which should limit the threat for flash flooding.
King
&&
.PREV DISCUSSION... /Issued 804 PM EDT Mon Aug 1 2022/
UPDATE...
Updated for the 00Z Aviation Discussion.
PREV DISCUSSION... /Issued 330 PM EDT Mon Aug 1 2022/
SHORT TERM /Tonight through Tuesday Night/...
Differential heating boundary developed this morning across central
portions of the CWA. North of this boundary, the atmos is a bit more
stable and thunder chances should be more limited. South of this
boundary, locales have received much more sunshine which has
destabilized the airmass. Thunder is more likely south of the
differential heating boundary this afternoon and evening. Locally
heavy rainfall should be the primary hazard this afternoon and
evening, especially with PWATS around 2" or above.
Do think with the loss of heating the chances for shra and tsra will
diminish. The hi-res models do keep the overnight hours fairly quiet
with some passing mid/high level cloudiness.
Convection tomorrow remains low confidence and may be dependent upon
any shortwaves that drop s/se in the upper flow. The HRRR is
producing a dying thunderstorm complex approaching north GA early
tomorrow morning, possibly re-firing across central GA during the
afternoon. Not going to completely go with this solution at this
time and will keep pops in a more diurnal summertime pattern.
NListemaa
LONG TERM /Wednesday through Monday/...
Through the long term, there isn`t really any significant changes to
make from day to day. High pressure will remain in control and any
actual flow in the upper levels will remain confined over the
northern part of the US.
With PW values approaching 2.0 inches any afternoon thunderstorm
could be efficient rain producers. Training storms could produce
heavy rains with some isolated flash flooding primarily across
northern Georgia where the 7 day QPF is expected to be the heaviest.
The tropics remain quiet and temperatures will stay in the upper 80s
and low 90s with HI values approaching triple digits through the
foreseeable forecast; which is on par with what we would expect
climatologically for the area this time of year.
Vaughn
AVIATION...
00Z Update...
A differential heating boundary remains in place to the north of
the southern TAF sites. With more instability to south, TSRA is
ongoing at CSG and is moving eastward towards MCN, warranting a
TEMPO for TSRA for both sites until 02Z. Scattered -SHRA is
ongoing in north Georgia, warranting VCSH at the metro ATL sites
and AHN until 02-03Z. Patchy fog is possible in portions of far
northwest Georgia overnight, but is not expected at any TAF sites.
Broken mid- level clouds are expected through the overnight hours,
with a scattered cu field developing between 030-050 after 15Z.
Scattered convection tomorrow afternoon has warranted a PROB30
for TSRA from 18-00Z at ATL. Winds will be primarily W to SW at
3-6 kts overnight, shifting to NW at 5-8 kts after sunrise
tomorrow.
//ATL Confidence...00Z Update...
Medium confidence on all elements.
King
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 71 92 72 95 / 20 40 20 30
Atlanta 73 90 73 93 / 20 40 20 40
Blairsville 65 86 66 89 / 20 40 20 40
Cartersville 70 90 70 92 / 20 40 20 40
Columbus 73 90 73 94 / 100 50 20 60
Gainesville 70 90 71 92 / 20 40 20 30
Macon 73 91 74 95 / 30 50 20 50
Rome 71 91 72 95 / 10 40 20 30
Peachtree City 71 90 71 93 / 20 50 20 50
Vidalia 73 93 74 95 / 90 40 30 60
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...NListemaa
LONG TERM....Vaughn
AVIATION...King
Area Forecast Discussion
National Weather Service Grand Forks ND
1045 PM CDT Mon Aug 1 2022
.UPDATE...
Issued at 1044 PM CDT Mon Aug 1 2022
A line of elevated thunderstorms had developed near the ND/SD
border west of our CWA just northeast of the warm front near the
main theta-e gradient/instability axis. This has may a slow east-
southeast progression and may pass into southeast ND if it holds
together. We are still looking at the potential for activity to
develop after 06Z tonight when this axis shifts east along with
the building LLJ. HRRR has show less consistency in
coverage/location of initiation this evening, though earlier CAMs
had been favoring the Highway 2 corridor. Regarding impacts,
there isn`t a change from previous discussions as activity will
tend to be in region of marginal instability. Adjustments were
made to PoPs/Wx to better reflect current trends and blend towards
recent trends in CAMs.
UPDATE Issued at 700 PM CDT Mon Aug 1 2022
Other than a few light returns still associated with the departing
wave, but thunderstorm activity in those regions has ended with
stabilization of BL. Next round is still projected to develop
later tonight as the LLJ and elevated CAPE axis upstream tracks
into our CWA, and no changes were made at this time regarding that
period. There may be just enough elevated CAPE (1000-1500 J/KG)
and effective shear (30-40kt) to support a few more
organized/taller updrafts, but mid level lapse rates tonight
aren`t particularly impressive and they would be brief/pulse type
cores within the larger cluster of showers/weaker thunderstorms.
Isolated/marginally severe hail may be the main threat, but
confidence isn`t high as the signal for best coverage is ahead of
the main push of higher instability.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 257 PM CDT Mon Aug 1 2022
Thunderstorm chances this afternoon into tonight and again Tuesday
evening remain the main forecast challenge.
Showers and developing thunderstorms continue over the northern
Red River Valley and will spread into northwest Minnesota in the
next few hours. Satellite imagery shows a few of these developing
storms gaining some height, but have yet to see any lightning. So
for the most part, it should be showers with embedded thunder in
this area. By mid to late evening, a weak low level jet and warm
advection develop, first focused along the highway 2 corridor
around Minot, gradually shifting along highway 2 eastward toward
Grand Forks during the late evening. There is also a 700mb wave
that trails slightly behind these features, which could also aid
in lift. The main limiting factor could be capping, with warm mid
level temperatures arriving in advance of the hot day expected
Tuesday. So think there will be scattered showers/storms forming
along the highway 2 corridor in ND, gradually transitioning to the
highway 200 corridor in MN very late tonight into Tuesday
morning.
Tuesday still looks hot and humid. Surface dewpoints now look to
reach into the mid to upper 60s, instead of low to mid 60s. Highs
will vary some from north to south, and these may be impacted by
residual cloud cover from the overnight convection. During the
day, 700mb temperatures rise to +10 to +12C over the FA, which
should cap any thunder chances. A cold front is expected to push
through Tuesday night, accompanied by a decent upper jet (mainly
across southern Canada). This should provide a window during the
evening for severe storms (lots of CAPE and abundant shear). HREF
2-5km UH tracks show a good cluster of long duration tracks up in
the Winnipeg area, with a couple along the border. SPC updated the
Day 2 convective outlook to include portions of northwest MN in a
slight risk to cover this.
.LONG TERM...(Wednesday through Monday)
Issued at 257 PM CDT Mon Aug 1 2022
The extended forecast period offers a chance for scattered tstms
late Fri into early Sat. Temps will be warmest on Thu and Fri.
The 500 mb flow pattern will still be a flattish ridge from the
central forecast area on south, with the primary jet focused near or
north of the International border. This setup will allow the
occasional shortwave to migrate along the periphery of this
interface.
Wed morning should see one of these waves exiting the region,
bringing cooler and less humid air in its wake, resulting in high
temps mostly in the 70s. Surface high pressure rolling in will be
mitigated by daytime heating to cause some CU production by late
morning.
It will turn warmer with lighter winds by Thu. Moisture increases
with developing SW flow aloft on Fri, bringing the next chance for
storms from late Fri into early Sat. Ensemble data do not, at this
early point in time, suggest potential for excessive rainfall or
severe storms. A return to drier and more seasonal weather is
indicated later in the weekend into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 700 PM CDT Mon Aug 1 2022
A warm front lifts over eastern ND and northwest MN tonight, with
low pressure tracking across the region Tuesday. VFR conditions
should prevail, with main aviation impacts related to possible
shower/thunderstorm activity in the 5-10Z period tonight (best
chances in northwest MN). Isolated thunderstorms can`t be ruled
out Tuesday afternoon, however high based CU currently is more
likely and best chances appear to be closer to the US/Canada
border Tuesday evening (after the current TAF period).
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
$$
UPDATE...DJR
SHORT TERM...Godon
LONG TERM...WJB
AVIATION...DJR
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1019 PM EDT Mon Aug 1 2022
.SYNOPSIS...
A weak warm front will drift north and dissipate tonight and
Tuesday. Sub-tropical high pressure over the western Atlantic will
take control of our weather pattern for the rest of the week. Expect
mainly afternoon and evening showers and thunderstorms each day and
these will be most numerous over the mountains.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 1000 PM EDT Monday: With the 500mb trough axis now positioned
along the eastern tier of the CWA, forcing has vanished and activity
has steadily diminished, leaving only a few spotty patches of
drizzle mainly across the SC Upstate. Anticipate general drying in
the northwest flow tonight. This may open the door for early morning
fog to expand across the NC mountains assuming the boundary layer
remains saturated enough to support it. Of somewhat lesser concern
is the advance of a deck of low stratus across the SC Upstate
around dawn. Guidance depicting this feature is in the minority,
and rightly so with westerly 850mb flow limiting low-level moisture,
yet the last few weeks have seen multiple instances of unexpected
low stratus development east of the mountains.
Potential remains for an MCS to run from the Ohio River Valley
toward the southern Appalachians through the early morning hours.
All guidance is unimpressed by the preceding environment for
MCS maintenance, and only the HRRR depicts any showers/thunder
penetrating the Appalachians. It`s likely that the southwest
mountains will see limited activity before dawn, but given the
poor timing it`s unlikely the area will see significant effects.
Nonetheless, Tuesday is beginning to look less and less exciting in
terms of convection. A pesky low-level stable layer will inhibit
much convection from developing, although the latest 2 runs of
the HRRR depict some cells firing up in the SC Upstate along what
was once the MCS`s cold pool. General thinking, however, is that
Tuesday will see below-climo coverage of convection.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of midday Monday: We look to remain under a weakly forced
regime Wednesday and Thursday. Anticyclone associated with the
Bermuda High will hold strong, as will another centered over
the southern Rockies; on some model runs this results in a weak
500mb low over the Deep South. Most likely we will continue to
see light southerly low-level flow as a result. The upper pattern
progresses slightly across the US northern tier, with flow becoming
quasi-zonal in between troughs. That appears of little consequence
for us during the short term period, aside from taking us out of
the MCS track. Heights continue a gradual rise as the Bermuda High
strengthens. Above-normal temps and seasonable diurnal convection
will be the main story. Dry sfc high pressure appears to somewhat
suppress activity Wednesday, especially over the eastern CWA, but
an effective warm front will reinforce the subtropical airmass
for Thursday, and PoPs rebound accordingly. A threat of locally
heavy rainfall and a seasonable risk of a stray damaging microburst
will continue.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 100 PM Mon: Anticyclones will persist invof the southern
Rockies/High Plains and the western Atlantic through the medium
range period. Deterministic global models depict us as remaining
under a relative weakness between these two features, but a
number of NAEFS members merge them into a very strong and broad
ridge which encompasses most of the eastern CONUS. Meanwhile,
progressive low-amplitude flow will continue near the US-Canada
border, on the northern periphery of the anticyclones. Broadly
convergent flow over the Eastern Seaboard, along with continued
light southerly winds and lack of any strong inhibiting features,
warrants above-normal PoPs. Furthermore, even those ensemble
members that merge the anticyclones still depict some diurnal QPF
across the region. Following the consensus of deterministic runs,
will feature temps falling back to around climo, but again the
possibility of the developing mega-ridge could instead result in
max temps a few degrees above.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: Showers tapering off across the forecast
area are expected to essentially vanish over the next 2-3 hours,
except for perhaps a few lingering sprinkles over the NC mountains.
Northwest flow still expected to maintain dry overnight conditions
as a convective line advances through the Ohio Valley. Guidance is
in good agreement that the brunt of this activity will dissipate
upon reaching the western tier of the Appalachians, largely failing
to produce rainfall at any of the TAF sites (though still can`t
rule out some light showers at KAVL). The mountain valleys will
be under the gun for some patch MVFR to IFR visibility restrictions
before dawn, and a spit of low stratus may affect the Upstate sites
during a similar timeframe. Otherwise, Tuesday looks to feature
low-end diurnal convection, mainly over the mountains with more
inhibited action elsewhere.
Outlook: A more typical summertime pattern is expected to return
by mid-week and persist through late week. Fog and low stratus
may develop each morning in the mountain valleys and wherever
appreciable rain fell the previous day.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...None.
SC...None.
&&
$$
SYNOPSIS...DEO
NEAR TERM...HG/MPR
SHORT TERM...Wimberley
LONG TERM...Wimberley
AVIATION...MPR
Area Forecast Discussion
National Weather Service Lincoln IL
919 PM CDT Mon Aug 1 2022
.SYNOPSIS...
Issued at 246 PM CDT Mon Aug 1 2022
Summertime heat and humidity will persist over the next week, with
the hottest day of the period coming on Wednesday when afternoon
temperatures reach into the mid 90s and heat index values surge
into the triple digits. This heat and humidity will be
accompanied by near daily chances for showers and thunderstorms,
some of which may be strong-to-severe.
&&
.UPDATE...
Issued at 849 PM CDT Mon Aug 1 2022
A back-building MCS will continue to fester across SE Illinois
over the next couple of hours. The thinking is that coverage and
rainfall intensity will wane over the next 1-2 hours as
instability diminishes with the loss of daytime heating. Even as a
modest LLJ continues to feed into a well developed cold pool,
thunderstorms should become a little less organized as the main
belt of westerlies moves SE of the region helping to decrease
deep-layer shear. An additional inch of rainfall could occur late
this evening south of I-70 where back-building may occur, and this
will not play well with locations that have already received
between 2-6" (localized 8"). While ARIs and other MRMS FLASH
metrics suggest this has been a significant QPF event, little
impacts have been noted to this point.
CAM guidance continues to exhibit strong run-to-run variability,
especially with additional nocturnal convection that may develop
across NE and IA overnight. With the surface boundary expected to
begin lifting northward over the next 6 hours, portions of west
central IL could be in the crosshair for another MCS into the
early morning hours of Tuesday. Current upstream satellite and
Radar trends do show convection spawning across northeast NE, and
we don`t see what would stop this activity from riding the theta-e
gradient all the way down into our area. If it does, isolated
strong-to-severe storms and brief heavy rainfall will accompany
it, though a stable near-sfc layer may mitigate widespread issues.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 246 PM CDT Mon Aug 1 2022
A frontal boundary, currently extending from Jacksonville-to-
Robinson, will provide the focus for thunderstorms this evening
across portions of south central Illinois. Some of these storms
may become severe given the current parameter space. The latest
19z RAP analysis depicts MLCAPE values exceeding 4500 J/k along
and ahead of the front with deep-layer shear around 40 kts.
Modeled soundings reveal an uncapped environment ahead of the
front, while hodographs reveal a long straight wind profile. This
points to a few organized multi-cells capable of producing
damaging wind and hail. The tornado threat is low, but stranger
things have happened near a boundary. Storms will likely wane by
02z/9pm with the loss of daytime heating.
Attention then turns toward the overnight period as the surface
front begins to waffle northward near the I-74 corridor. Eyes will
need to be over E Nebraska and W Iowa tonight to see if an MCS
develops ahead of a mid-level shortwave and modest LLJ. If it
does, and afternoon CAM guidance currently provides little help
at this point, it will almost certainly ride the instability
(theta-e) axis into central Illinois. Shear/CAPE profiles support
MCS maintenance, but a robustly stable near-sfc layer could
mitigate a severe/damaging wind threat. Rather, it could be a nice
rainmaker for us in central Illinois, with QPF values ranging from
a few tenths, while localized values could exceed an inch.
.LONG TERM...(Wednesday through Monday)
ISSUED AT 246 PM CDT Mon Aug 1 2022
Wednesday looks to be the warmest day of the week with highs
expected to be in the low to middle 90s. Heat indices will make it
feel warmer than that though with values looking to range between
100-110. A Heat Advisory may be needed for most of the area on
Wednesday. However an approaching cold front may throw a wrench in
this as cloud cover and precipitation chances increase from
northwest to southeast Wednesday afternoon into evening. The front
looks to slowly sag southward through the area bringing
widespread precipitation chances and even the threat for some
severe weather Wednesday evening. A good soaking rain appears
likely for much of the area, which is very much needed especially
in parts of eastern IL where drought conditions continue.
Temperatures for the end of the week will be a little cooler due to
ongoing precipitation as the front slowly works through the area.
Another bout of heat is possible this weekend as upper ridging
builds over the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 644 PM CDT Mon Aug 1 2022
VFR conditions will persist through 06z/1am tonight, at least. A
complex of showers and thunderstorms may then move into central
Illinois overnight into Tuesday morning. Confidence is low, but
coverage could be widespread. This was enough for vicinity mention
at all regional terminals. Flight categories may lower into the
MVFR range early Tuesday morning if moderate rainfall does spread
in from the west. Additionally, with winds becoming light and
variable overnight, some patchy fog may develop and reduce flight
categories into MVFR or IFR. The best signal for this right now is
at CMI. A return to VFR conditions is then likely by Tuesday
afternoon, beyond 18z.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MJA
SYNOPSIS...MJA
SHORT TERM...MJA
LONG TERM...MJA/NMB
AVIATION...MJA
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1140 PM EDT Mon Aug 1 2022
.UPDATE...
Issued at 1140 PM EDT MON AUG 1 2022
The evolution of convection overnight continues to be uncertain.
However, the overall consensus is for at least some increase in
convection overnight, with the trend toward later. Some of the
most recent HRRR guidance suggests convection to the north and
northeast and to the southwest of the region generally splitting
the area with the convection to the southwest perhaps robbing
moisture transport into the area. There has been so much run to
run and model variability in placement and development, with
signals for a heavy rain threat remaining across the general
region including in the 0Z HREF 3 hour max QPF and PMM QPF late
tonight. FFG values remain low in several areas. Thus, the Flood
Watch remains in effect.
The threat for severe weather, gusty to damaging winds, appears
to have diminished, however.
Hourly grids have been adjusted to push back some of the higher
pops and align with recent observations and trends.
UPDATE Issued at 905 PM EDT MON AUG 1 2022
So far, showers and thunderstorms have remained north and west of
eastern KY either in areas of greater CAPE or near the MLCAPE
gradient. However, a shortwave trough is upstream of the region
and models suggest an increase of moisture transport back into the
region as this feature passes late this evening into the
overnight hours. Additional convection should develop toward
midnight and into the overnight hours and generally move from
north to south. Convective allowing models still suggest heavy
rain rates and rainfall totals of 1 to 2 inches are still possible
in a few locations in the region. With the ground saturated
an inch or a little less in an hour or 1.25 to 1.5 inches in 3
hours would be enough to lead to a renewed flood risk.
Some convective allowing models also suggest the potential for
some outflow gusts and with the ground as saturated as it is, sub
severe gusts would be capable of bringing down a few trees. The
region remains under a slight risk for excessive rainfall tonight
and a marginal risk extending into tomorrow. A slight risk of
severe thunderstorms is also in place. Damaging wind gusts remain
the primary threat though some hail or an isolated tornado cannot
be completely ruled out given the anticipated effective shear in
the 25 to 35KT range. The warm and moist airmass combined with the
shear may lead to a few rotating storms with heavier rainfall
rates.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 653 PM EDT MON AUG 1 2022
A broad upper level trough over the northeast CONUS was providing
WNW flow over the Ohio Valley, supporting a cold front which was
heading southeast through the Midwest. Another boundary/line of
convergence was located north of the Ohio River, ahead of the
front. Convection is erupting along this prefrontal boundary this
afternoon. Forecast models have been anticipating this, but they
have been very inconsistent in its evolution through the night.
Based on earlier model runs, a Flood Watch was issued for tonight
into Tuesday morning, rather than letting a preceding watch
completely expire with a potential for another one having to be
issued shortly afterwards. Some mesoscale runs are now suggesting
that the convection may largely split around the JKL forecast area
tonight, but confidence in the eventual outcome remains low. With
the state of our ground, it will not take much rain by summertime
standards to cause problems, and the watch remains in place.
The other concern is a severe wx threat. Should convection
move/develop southward into the JKL area later this evening, the
forecast parameters are concerning. ML CAPE of 1500 J/Kg east to
2500 J/Kg west, with decent low-mid level shear (sfc-1km, sfc-
2km, and sfc-3km) of 200-250 m2/s2. All that said, the slight risk
from SPC blankets the forecast area, and we`ll wait and see.
The overnight activity should fade and depart the region early
Tuesday. The frontal boundary will still be to our north, and
models show as least some minor redevelopment of convection over
our southwest counties after diurnal destabilization occurs,
possibly lasting into the evening before waning. The front looks
like it will only make to our doorstep by late Tuesday. Going into
Tuesday night, the upper level trough will be departing and
geopotential heights rising. As that occurs and the front heads
away as a warm front, our POP should drop off.
.LONG TERM...(Wednesday through Monday)
Issued at 355 PM EDT MON AUG 1 2022
A warm front will lift northeastward from the Ohio Valley into the
Mid-Atlantic and Northeast early Wednesday, causing a warmer, humid
airmass to settle over the region. High temperatures are forecast to
be at or just over the 90 degree mark for both Wednesday and
Thursday. The main concern however is the dew point values, which
will range in the low to mid 70s.
Confidence in high temperature values are dependent on how well the
boundary layer and low and mid level cumulus mix out during the peak
heating hours. The MOS guidance has leaned towards more saturated
cloud layer, which may keep readings in the mid to upper 80s. With
all that mind, considering the flash flood cleanup efforts will
still be ongoing in the effected communities and there are still
numerous communities without power, the heat indices during the
afternoon hours are projected to be in the upper 90s to low 100s.
While these values fall below heat advisory criteria, it is
essential that people that are outdoors practice heat safety both
Wednesday and Thursday.
Overnight temperatures Wednesday night through Thursday morning are
projected to be in the upper 60s to low 70s. Patchy to dense river
valley fog is possible to form, especially over the eastern and
southeastern counties.
A mid level trough and associated cold frontal boundary will push
southeastward from the northern Midwest into the lower Great Lakes
and Ohio Valley on Thursday into Friday. Concurrently, a mid level
ridge will propagating eastward from the Plains and Southwest; which
could hamper the southward progression of the frontal boundary. The
ridge`s influence may cause the front to slow and even stall west to
east along central Indiana and Ohio; which would pin the heaviest of
the rainfall along and north of the Ohio River.
The region itself should see scattered showers and thunderstorms
beginning midday Thursday. Coverage is projected to increase by
Friday afternoon and evening, before diminishing eastward by
Saturday. The environment during the day Thursday and Friday is
weakly forced with the instability and lapse rates looking weak.
Even so, the forecast PWAT values will still range from 1.50-2.50
inches. Depending on the spread and coverage of the rainfall,
isolated flash flooding is possible.
Unsettled weather is may continue through the weekend and into the
early half of next week, but is entirely dependent on the
progression of the primary storm track. Cluster analysis split into
drier and wetter solutions for the region. The drier solution
involves the ridge axis moving further into the Midwest and Plains,
which lifts the boundary northward. The wetter solution features the
boundary settling along the southern Great Lakes into Mid-Atlantic,
which would support daily rounds of showers and storms. As of now,
the wetter solution is favored within the cluster analysis, but
forecast confidence is minimal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 835 PM EDT MON AUG 1 2022
Mostly VFR with some MVFR was reported across the region at
issuance time. However, during the first 3 to 6 hours of the
period, showers and thunderstorms are expected to develop
southward through the region. As the night progress and the lower
levels saturate, particularly across the southeast and to an
extent the northeast as well, a period of sub-VFR conditions,
generally after 6Z is expected in these areas where the coverage
of showers and storms is expected to be greatest. Ceilings should
improve to the VFR range in all areas by the 12Z to 18Z period.
As for the thunderstorm threat VCTS was included in the TAFs
starting around 3Z to 4Z. Some of these storms may contain strong
winds and very heavy rain rates. This precipitation should taper
off gradually from north to south during the 6Z to 13Z period.
Overnight and during the early morning, there could be some fog
that develops, especially in valleys. Any fog will dissipate
toward 13Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
Flood Watch until 9 AM EDT Tuesday for KYZ044-050>052-058>060-
068-069-079-080-083>088-104-106>120.
&&
$$
UPDATE...JP
SHORT TERM...HAL
LONG TERM...LUEHRS
AVIATION...HAL/JP
Area Forecast Discussion
National Weather Service Louisville KY
1144 PM EDT Mon Aug 1 2022
.Forecast Update...
Issued at 1143 PM EDT Mon Aug 1 2022
After chatting with SPC and neighbors, allowed the Severe
Thunderstorm Watch in central Kentucky and central parts of southern
Indiana to expire on time. The watch has been extended until
midnight CDT for western Kentucky and southwest Indiana where severe
storms are ongoing and where the greatest short term threat resides.
Forecast confidence is low for the rest of the night, but it does
appear that additional thunderstorm development will be possible. An
east-west cold front remains well to our north across Indiana and
KLVX VWP is sampling a 30-40kt low level jet streaming across
Kentucky into West Virginia. A corridor of pooling above-normal
precipitable water air is coincident with the jet, ahead of the
front. Models, which have not been stellar with this event, do at
least suggest increasing 850mb theta-e values as theta-e ridging
currently reaching from Nebraska to southern Illinois spreads east
into the Ohio Valley. Though the surface front will remain to our
north and a 5H speed max near Chicago is expected to weaken slightly
and also remain to our north, will have to hold on to the
possibility of additional thunderstorm development in the middle
Ohio valley overnight, especially across southern Indiana and north
central Kentucky in that corridor of increased atmospheric water
content lined up with the LLJ ahead of the east-west cold front.
Instability, mid-level lapse rates, and deep layer shear will remain
sufficient through the night for organized convection, and DCAPES
will remain above 1000 J/kg, so we will continue to be on the
lookout for gusty winds. However, the main threat overnight may
actually be flooding because if storms do get going then they will
have very deep warm cloud depths and will likely train from WNW to
ESE and will be capable of producing locally very heavy rainfall
amounts.
Issued at 520 PM EDT Mon Aug 1 2022
At this hour, scattered showers and thunderstorms are developing
across central IL and central IN and drifting off to the ESE. These
storms will begin to move into Washington/Scott/Jefferson IN over
the next half hour or so. Expect cells to gradually work SE later
this evening and into the overnight hours. With 2500-3500 J/kg
MLCAPE and 900-1300 J/kg DCAPE across the area at this hour,
damaging winds will be the primary threat with storms later this
evening. However, modest low-level SRH does exist, particularly
along and north of I-64, so an isolated spinup tornado cannot be
ruled out. Lapse rates are modest, but cannot rule out isolated
severe hail later this evening as well.
Given all these factors, a severe thunderstorm watch has been issued
across southern IN and portions of north central KY until 03Z. For
now, areas across the KY Bluegrass and south central KY are not
included in the watch, though this may need to be expanded
downstream as convection develops.
&&
.Short Term...(This evening through Tuesday)
Issued at 330 PM EDT Mon Aug 1 2022
Early afternoon analysis and GOES imagery reveals the upper
shortwave is over the Ohio Valley, with the sfc low located over the
Great Lakes region. Early morning convection dissipated as it
tracked into the Ohio River vicinity, and subsidence in it`s wake
has resulted in a quieter afternoon. A scattering of cu has provided
enough clearing along with weak WAA to realize upwards of 3000 J/kg
of SBCAPE and sfc temps ranging in the mid to upper 80s. The remnant
boundary from the morning convection stretches across southern IN
this afternoon, and should be the focus for redevelopment of showers
and storms this afternoon and evening.
SPC highlights a majority of our region with a Slight Risk of severe
weather for this evening. Model soundings show relatively dry mid
levels, enhancing our DCAPEs to around 1000 J/kg or above, which
will support damaging wind gusts as the primary hazard.
Additionally, there will be sufficient shear for a severe threat,
though adequate veering in the lowest levels do support a low-end
tornado threat as well. SPC HREF and some model soundings suggest
SRH values up to 200 m2/s2, with effective bulk shear values over 30
kts. Per SPC, cannot rule out a tornado or two within the 2% risk
area should any embedded supercells within the larger clusters
encounter sufficient low-level moisture to allow LCLs to drop. We
should see convection weaken through the night as it tracks further
southeast and into more stable air.
The main concern with the short term is confidence on timing and
exact location of greatest chance of PoPs. Model guidance has been
varied and initializing poorly, so solutions have been all over the
place. Believe the HRRR has been one of the better models
initializing today, so have leaned heavier on HRRR/HREF solutions
with this forecast package.
Shower and storms chances will be possible again tomorrow, though
confidence remains low at this time. There is potential for another
MCS feature to dive southeastward out of IL/IN and into KY, but not
all solutions support this. If this does not occur, think there`s
still a good chance at seeing afternoon shower and storm chances. We
should have a remnant outflow boundary across the region, which
should be the focus for convective redevelopment as daytime heating
increases instability and steepen lapse rates. Overall should have
weaker deep layer shear, plenty of buoyancy should result in strong
storms. SPC has drawn up a Marginal risk in the Day 2 update.
.Long Term...(Tuesday night through Monday)
Issued at 245 PM EDT Mon Aug 1 2022
Hot and oppressively humid conditions are expected on Wednesday.
Showers and thunderstorms will accompany a weak and slow-moving cold
front Thursday and Friday. The weekend will be very warm and humid
with daily thunderstorm chances as we remain in a stagnant weather
pattern.
Wednesday looks to be the one mainly dry day this week, with
isolated convection limited to the Lake Cumberland area. Very warm
mid-level air will limit boundary-layer growth and trap a very humid
air mass below an inversion near 850mb. Highs in the lower/mid 90s
coupled with dewpoints in the lower/mid 70s will push the heat index
above 100, mainly along and west of I-65. Will keep a close eye on
this for potential need for a Heat Advisory.
Weakening cold front and upper trofiness will take over on Thursday,
with the front washing out over the Ohio and Tennessee Valleys by
Friday. Moderate instability and copious moisture will support a low-
end pulse wind threat, as well as a heavy rainfall threat. Best
chance of heavy rainfall will be Thursday across southern Indiana
and north-central Kentucky.
The pattern stagnates for the weekend, so we`ll carry continued
diurnal T-storm chances, with temps trending back up to the high
side of climo after being held in check Thu-Fri.
&&
.Aviation...(00Z TAF Issuance)
Issued at 750 PM EDT Mon Aug 1 2022
Current satellite and radar imagery show mostly clear skies across
Kentucky while an expansive cloud shield remains in place over
southern IN. This is in association with a cluster of storms that is
pushing SSE through far southwestern IN, about 25 miles west of
KHNB. While model guidance has not shown much run-to-run
consistency, have opted to keep thunder mention out of the TAFs due
to low confidence and covered the precip potential with TEMPO and
PROB30 groupings where appropriate. Another cluster of showers and
storms will be possible Tuesday, but due to low confidence in timing
and location, have not included any mention in the TAFs.
&&
.LMK WATCHES/WARNINGS/ADVISORIES...
IN...None.
KY...None.
&&
$$
Update...13/CSG
Short Term...CJP
Long Term...RAS
Aviation...JML
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
902 PM CDT Mon Aug 1 2022
.UPDATE...
Issued at 900 PM CDT Mon Aug 1 2022
No major changes to forecast thinking through tonight and will
only be tweaking hourly temp/wind/sky trends slightly. Will
continue with shower/thunder chances near and south/southwest of
a Dixon to Gardner to Hoopeston line as noted by the previous
shift starting at 10z. Evening soundings from DVN and ILX continue
to show a very dry and capped column while OAX and SGF to the
southwest show much higher moisture and instability as expected.
The sharp moisture/instability gradient will shift to the
east/northeast overnight while a wave of ascent currently
generating storms over eastern Nebraska tracks southeastward. 10z
may be a bit early for any shower/thunder chances in the local
area and any activity may remain just to the southwest but do not
see much reason to make any notable changes at this time.
MDB
&&
.SHORT TERM...
Issued at 317 PM CDT Mon Aug 1 2022
Through Tuesday night...
Main concerns:
* Thunderstorm potential early to mid Tuesday morning for the
southwest 1/3 or so of the CWA
* Very warm and increasingly humid conditions on Tuesday away from
the immediate Illinois lakeshore
The post cold frontal air mass across the area remains moderately
humid amidst moderate west-northwest winds. Conditions tonight
will be quiet and warmer than last night through most of the night,
with the main period of interest being just prior to dawn through
about mid morning Tuesday. A plume of very steep mid-level lapse
rates resides off to the southwest of the local area, though the
column is quite parched. Sufficient moisture is the big question
mark as to thunderstorm development and coverage into any portions
of the CWA Tuesday morning.
As alluded to above, the post frontal air mass features very
parched mid-levels down to a narrow 850-800 mb moist layer. A
convectively modulated impulse will cross the MS River into
western Illinois late tonight. Moistening of the dry layer aloft
in response to the short-wave will result in a large MUCAPE
reservoir essentially sliding eastward, albeit with a sharp
northwest to southeast oriented instability gradient. This will be
due to the air mass just north and east of the instability
gradient remaining much drier in the mid-levels and thus capped.
The CAM solutions as you`d expect run the gamut from a total lack
of convection in the far west and southwest/southern CWA to fairly
widespread coverage (ie. 12z HRRR with more robust coverage to
18z HRRR devoid of convection). This is a common setup for the
CAMs and even the operational guidance to struggle. The above
being said, there was enough of a signal on the HREF mean to
maintain a similar forecast message to the previous issuance (with
a tighter PoP gradient), offering a sliver of chance PoPs near
and south/southwest of a Dixon to Gardner to Hoopeston line, with
slight chance padding a bit north and east of this line.
Potential magnitude of MUCAPE, steep mid-level lapse rates, and
about 30 kt of effective deep layer shear introduces a conditional
risk for organized elevated thunderstorms and a threat for hail,
and wind if cold pool development occurs (similar to this/Monday
morning). Furthermore, incoming moisture rich air mass northeast
of surface warm front will support torrential downpours in
thunderstorms and a threat for localized flooding contingent upon
more widespread coverage and temporary training. Threat timeframe
looks to be roughly in the 5AM-10AM range.
A sliver of dry air aloft through most of the rest of the CWA
should provide a fairly sharp northeastern terminus of
thunderstorm potential. If thunderstorms do get going in southwest
sections, can`t rule out storms festering south of US-24 or so
into the early afternoon. Otherwise, the main story will be the
incoming very warm/hot and humid conditions as a warm front surges
north. Progged 925 mb temps and expectation of a good amount of
sunshine through peak heating supports highs in the upper 80s-
around 90/locally low 90s away from the Illinois lakeshore and
possibly immediate Indiana shore. Weak enough flow aloft initially
and the increasing land-lake thermal gradient should allow a lake
breeze to slip inland and keep highs in the low 80s for shore
locales. Dew points rising into the low 70s outside of Chicago
Tuesday afternoon will yield peak heat indices in the mid to high
90s.
Most of Tuesday night will also be quiet, with the lake breeze
receding back to the lake as southerly flow ramps up aloft. A
strong and low based low-level jet will develop and peak
overnight, with increasing south-southwesterly winds becoming
gusty overnight. Expecting temperatures to warm in the pre-dawn
hours through sunrise Tuesday in response to low-level warm
advection. Can`t completely rule out thunderstorms far north prior
to 12z Wednesday, but most of the threat will focus during the
day Wednesday through Wednesday night, detailed in the long term
discussion below.
Castro
&&
.LONG TERM...
Issued at 317 PM CDT Mon Aug 1 2022
Wednesday through Monday...
Main concerns in the period focus on a potentially active
Wednesday into Wednesday night, with heat followed by possibly
strong to severe storms and a heavy rain threat.
An elongated upper trough will sag southeast toward the area on
Wednesday, with a corresponding low-level boundary focused from
Lake Superior into the central Great Plains. Ahead of the
boundary, low- level capping will keep conditions dry in the warm
sector ahead of the front/wave through most of the day (unless the
wave becomes more progressive as some guidance is hinting at
today). Surface dew points rising above 70F combined with temps
into the low to mid 90s will yield heat index values over 100F for
much of the area and over 105F for the south half of the CWA.
While forecast temps have trended lower over the past few days,
heat headlines may still be needed for portions of the forecast
area.
Severe thunderstorms: MLCAPE values will increase to over 3000
J/kg ahead of the front conditional on the mid-level wave and
possibly additional moisture pooling eroding the remaining modest
cap. While deep-layer shear will be quite low at 20 knots or less,
explosive convection can be expected in this environment with
tops quickly growing to 45kft+. With a high Pwat airmass in place
and likely rapid growth, severe risk will initially be limited to
localized microbursts before storms may congeal into clusters or a
broken line with a continued damaging wind risk. It should also
be noted that the low-level shear profiles will become somewhat
more favorable for a brief tornado or two if any QLCS structure
does develop, with formation driven by stretching under quickly
developing updrafts vs. any sustained embedded supercell
structures.
Heavy rain: An expansive area of Pwats over 2" driven by dew
points into at least the low 70s ahead of the front/wave will
allow for substantial rain rates with any convection Wednesday
afternoon into early Thursday morning. Overall weak deep-layer
flow only slightly oblique to the low-level boundary will support
a slow southward drift of convection. Meanwhile, backward
propogating vectors will turn northeast to east during the
evening. The potential for any extensive training convection will
initially be limited by 1) a veered LLJ angled roughly 30 degrees
off the low-level boundary and 2) the potential for a cold pool to
focus convection gradually southward with time. Concerns for a
more prolonged period of training convection will increase on
especially the southwest flank of the convection if the boundary
begins to lay out more west to east with time during the evening,
ultimately increasing the influence of the SW LLJ.
Beyond Wednesday night, convective trends become less clear as
the effective front from convection stalls somewhere across
central or southern Illinois. With the mid-level trough becoming
increasingly sheared over the southern Great Lakes, lingering
forcing will be sufficient for at least some continued shower and
embedded storm coverage across the southern CWA well into
Thursday. However, any extensive cold pool Wednesday night would
push the effective front much farther south and favor a drier
forecast on Thursday. Additionally, stronger northerly winds
Thursday into Friday will increase the risk for dangerous swimming
conditions on Lake Michigan.
High pressure and broad ridging will attempt to build back in
from the southwest late week into the weekend before another
trough brushes the Great Lakes region and brings new chances of
convection late weekend.
Kluber
&&
.AVIATION...
For the 00Z TAFs...
The primary aviation weather concerns through the 18Z TAF period are
as follows:
* Southeasterly winds becoming south-southwest Tuesday afternoon.
A ridge of high pressure will crest the area tonight which will
allow the current breezy northwest winds to become light and
likely somewhat variable into the late evening and overnight
hours. A southeasterly direction is favored Tuesday morning with a
more sustained south to southwest direction developing through
the afternoon from west to east. The exception will be GYY which
should remain easterly for much of the day thanks to the proximity
to the lake, but low level southerly wind speeds should be enough
to overcome the lake influence late in the afternoon.
MDB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Medford OR
549 PM PDT Mon Aug 1 2022
Updated AVIATION Section
.SYNOPSIS...An upper low just off the coast of far northern
California will remain nearly stationary and result in continued
chances of thunderstorms and showers over the area through at
least Wednesday (and possibly Thursday). Additionally, with
southerly to southwesterly winds aloft, smoke from wildfires in
Siskiyou County, California will continue to move northward into
Southern Oregon creating air quality concerns.
KEY POINTS:
*Smoke from area wildfires may create periods of degraded air
quality. Please see the AQAMFR or the Oregon DEQ website for
more details.
*Thunderstorms may produce occasional to abundant deadly cloud to
ground lightning, gusty and erratic winds, and small hail.
*Periods of moderate to heavy rain will be possible in
thunderstorms today and Tuesday.
*Lightning may ignite new wildfires. More information is available
in the fire weather section below.
&&
.DISCUSSION...Satellite imagery is showing some cumulus build ups
across portions of southern Oregon and northern California.
These clouds are part of a larger shortwave moving northward from
Central/North California. Shower and thunderstorm activity should
increase through the evening and possibly continue overnight. A
brief break is expected Tuesday morning before the next round of
showers and thunderstorms are expected Tuesday. Models and
ensembles thus far have struggled to pinpoint which day will be
the main event, suggesting that Sunday, Monday, and now Tuesday
will be our heavy thunderstorm day. It is at least worth noting
that thunderstorms have been occurring in portions of southern
Oregon and northern California, especially in areas without
extensive smoke from the McKinney fire.
Speaking of smoke, air quality as shown on fire.airnow.gov and the
Oregon DEQ website suggest less smoke is over the Rogue Valley
this evening. However, the current thought is that smoke should
generally increase in southern portions of the valleys in Jackson
and Klamath Counties. Overall, the lack of smoke makes things a
bit more interesting as far as thunderstorms this evening and
overnight is concerned. Earlier discussions mentioned the morning
sounding Precipitable Water Column that was a daily record at 1.62
inches. This is combined with an impressive 65 degree F dewpoint
temperature, which is more typical of Midwestern summers which
draw in moisture from the Gulf of Mexico. It will be interesting
to see how the precipitable water stacks up in the sounding this
afternoon. What this means is that the showers and thunderstorms
will be wet in nature, producing periods of moderate to heavy
rain. While we don`t anticipate any issues with area burn scars in
western Siskiyou County (the River Complex), we will have to keep
an eye on things. Additionally thunderstorms will have the
potential to become strong once again today with wind gusts to 40
to 50 mph and some small hail.
This pattern will continue over the next couple of days as the low
wobbles in place. The other pattern this low is intermixed with is
a ridge of high pressure over the 4 corners region of the US. This
will nudge a bit westward which may help lessen thunderstorm
chances after Wednesday. Thus, while we are still carrying a
slight chance, confidence is very low at this point. Still, the
low will remain stationary for the next several days bringing deep
southwest flow. The westward nudge of the ridge could nudge the
low a bit westward as well, allowing tropical moisture from
tropical storm Frank to move into our area over the weekend into
next week. Although not currently in the forecast, this could
create additional precipitation chances for the area. Keep an eye
to the forecast for updates.
&&
.AVIATION...02/00Z TAFs...IFR and LIFR conditions in marine stratus
will continue to impact areas over the coastal waters and along
the coast, including North Bend, through the TAF period.
Inland, overall, expect VFR, but scattered showers and thunderstorms
from northern California up the Cascades over to the East Side may
bring local MVFR at times through Tuesday. Thunderstorms are most
numerous right now east of the Cascades in Lake County. Areas of
IFR/MVFR vis in haze/smoke in the vicinity of the McKinney fire will
persist in northern Siskiyou County and into the south end of the
Rogue Valley, up towards Medford, but also over to around Klamath
Falls. The main shower/t-storm area will shift to the NE part of the
forecast area by Tuesday morning. Then, another round of convection
is expected Tuesday afternoon and evening, but this time likely
initiating farther west in Siskiyou, Jackson and Josephine Counties.
-Spilde
&&
.MARINE...Updated 200 PM PDT Monday, 1 August, 2022...A weak upper
low will remain centered west of the waters through tonight. There
is much less instability over the coastal waters today compared to
yesterday. There is still the wee little chance of an isolated
thunderstorm over the coastal waters this evening but at this time
we are just expecting scattered alto cumulus clouds over the very
extensive low marine layer clouds.
In terms of the synoptic pattern, light north to northwest winds are
expected through Wednesday as the offshore low drifts westward.
North winds are then likely to increase, possibly reaching advisory
levels Thursday afternoon as a thermal trough develops and
strengthens. This is expected to build steep seas to advisory levels
Thursday evening into Friday.
Additionally, smoke from inland wildfires and marine layer fog will
reduce visibilities across the coastal waters, and could become very
dense at times. -Sargeant
&&
.FIRE WEATHER...230 PM PDT Monday, 1 August, 2022...
Red Flag Warning headlines for today and the watch that was out for
tomorrow have been combined into one warning, valid through 11PM PDT
Tuesday, primarily due to a shortwave trough moving into the forecast
area this evening through early Tuesday morning. This shortwave
trough is likely to enhance showers and thunderstorm activity during
the overnight time period and, likely, draw it back westward to
areas west of the Cascades. There`s then likely to be a bit of a
break in the action late Tuesday morning into early Tuesday
afternoon before we see another round of what`s likely to be
significant thunderstorm activity in the afternoon and evening.
More specifically, cloud cover and light showers continue this
afternoon from the Marble Mountains to the Siskiyous, and northward
along and near Cascades. This cloud cover and shower activity will
limit the potential for thunderstorm development in that area for
much of the afternoon, but there will be an increasing probability
of some embedded lightning strikes in that shower and cloud shield
as we head into the afternoon and evening. Areas west of that cloud
shield, from west of the Klamath River in Siskiyou County to
Josephine and Douglas counties bear some watching for surface based
thunderstorm development as surface heating into the mid 90s and
dewpoints well into the 60s combine. However, there`s also a hazy
smoke shield from about Grants Pass northward that will hinder
thunderstorm development some there. East of the cloud cover, across
Modoc and Lake counties heat is building, but moisture values are
not as high. Thunderstorms are expected to develop in that area mid-
late afternoon and then tap into extensive moisture west of there to
expand westward this evening. All in all, through the afternoon,
we`re watching the more cloud free areas for potential rapid
development of thunderstorm activity with lesser activity likely
elsewhere.
This evening through early Tuesday morning an upper level impulse
moving northward from the San Francisco Bay area is expected to
increase shower and thunderstorm coverage across the forecast area,
to include some areas west of the Cascades. The HRRR model, which
parameterizes smoke in its forecast, has been consistent in bringing
a low pressure vortex of showers and thunderstorms through Siskiyou
and Jackson counties overnight. There has been some question as to
whether or not Josephine and Douglas counties get in on the action,
how much ride through the Mount Shasta FWZ 282, and how much is rain
versus thunderstorms. Overall signals indicate it is a significant
concern for down strikes as it moves in, but will likely morph into
an area of rain as it encounters extensive smoke from the McKinney
Fire and heads onto the east side. There, it`s likely to slow and
rain itself out.
After a brief lull late Tuesday morning into early Tuesday
afternoon, a new round of scattered showers and thunderstorms is
expected to develop from western Siskiyou County, Josephine County,
and eastern Douglas County eastward. Abundant lightning, gusty
outflow winds, and locally heavy rainfall are all possible with the
thunderstorms. Localized severe thunderstorm warning level wind
gusts around 60mb will be possible, as well as small hail, and
locally heavy rain that could result in urban and small stream
flooding in some areas.
Please note that we have significant fire start concerns due to the
ongoing dryness of the vegetation due to our long term drought and
recent record breaking heat wave. At the same time, record high
precipitable water values today mean that storms the next couple of
days will be energetic and capable of locally heavy rainfall that
will slow or prevent fire growth. This could result in hold over
fires once we dry out again. Finally, gusty outflow winds of 40 to
60 mph will be possible with the stronger thunderstorms. After
Tuesday, it looks like lingering shower and thunderstorm activity is
more likely to be south and east of us and/or isolated if it`s in
our area (most likely Friday). ~BTL
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Red Flag Warning until 11 PM PDT Tuesday for ORZ617-620>625.
CA...Red Flag Warning until 11 PM PDT Tuesday for CAZ280>282-284-285.
Pacific Coastal Waters...
None.
$$
Area Forecast Discussion
National Weather Service Nashville TN
958 PM CDT Mon Aug 1 2022
...New UPDATE...
.UPDATE...
Issued at 958 PM CDT Mon Aug 1 2022
MCS complex moving into central KY within northwesterly flow
aloft. Had initially very hard time with any CAMs even
initializing this complex correctly yet project its movement
potentially into possible Upper Cumberland Region later this
evening. However, the 02/00Z NAM12 solution came in, initialized
this complex quite well, and projects its movement across Upper
Cumberland Region 02/05Z(Midnight)- 02/06Z(1 AM CDT Tuesday). SPC
Mesoscale Analysis showing ample instability and moisture across
this portion of mid state region to support numerous shower and
thunderstorm development during this time frame across these
locations also. Will continue to mention isolated to scattered
showers and thunderstorms across areas southeast of this complex
from late evening through overnight hours also. Updated suite of
forecast products this evening to reflect above reasoning.
Certainly can not rule out some embedded strong to severe
thunderstorms within this complex with strong to damaging winds,
large hail, and brief heavy downpours main concerns. Tweaked
current temperature, dewpoint, and wind speed/direction grids
blending them with associated previously forecasted hourly late
evening and overnight gridded values. Current temperature trends
generally in line with forecasted lows. Remainder of forecast
continues to be on track.
&&
.SHORT TERM...
(This afternoon through Wednesday Night)
Issued at 225 PM CDT Mon Aug 1 2022
Convection has virtually ended across our southern counties. Drier
air now working in with some added capping now in place.
The pattern coming up is somewhat typical for mid summer with a
frontal boundary meandering a good distance to our north. Warm humid
air in the lower levels will ride northward toward the boundary on
the heels of a strong LLJ. This sets the stage for MCS development
and with the northwest flow in place in the mid and upper levels,
mcs trajectories can have an eye on middle TN.
That said, upcoming, we do see mcs development upstream over the
next 24 hours. Trajectories indicate potential impact mainly over
eastern middle TN late tonight and then over a broader chunk of the
area on Tuesday. We are in a marginal risk in our north central and
northeastern counties for tonight. We are also in a marginal risk
for all of middle TN during the afternoon on Tuesday with that
second mcs.
It appears that for tonight, the best chance of strong to severe
storms will be over our eastern areas. Latest Hrrr shows the complex
actually missing our entire area and staying east. The trajectory
will be difficult to pinpoint with a lack of cams agreement.
Moreover, the MCS in question has yet to develop to our northwest.
Will therefore keep pops at modest levels for the overnight. For
Tuesday, cams offer some better agreement with more in the way of
widespread showers and tstms for much of the mid state. Much of this
activity will be during the afternoon with strong to severe storms
possible.
As we move into Wednesday, the northwesterly flow will transition to
lighter westerlies. This should offer a break from the convection.
For the near term temps, look for warm and muggy conditions to
prevail. Lows in the lower 70s and highs lower to mid 90s. Dewpoints
will not be over the top so no heat advisory issues expected.
&&
.LONG TERM...
(Thursday through next Monday) Issued at 225 PM CDT Mon Aug 1
2022
In the extended forecast, A shortwave axis will emerge on Thursday
and Friday with an increase in shower and tstm chances. The axis
will shift east with upper ridging then attempting to fill that void
over the weekend. However, the northern periphery of the ridge will
be subject to some degree of weakness intrusion. Thus the convective
chances will continue.
Temperatures through the extended period continue to look rather
steady state, but on the warm side. Look for lows in the lower to mid
70s and highs mostly lower 90s.
7 day qpf totals look like around 1 inch west with 1 1/2 inches
east.
&&
.AVIATION...
(00Z TAFS)
Issued at 617 PM CDT Mon Aug 1 2022
VFR will continue this evening at all terminals. Some models are
showing a storm complex diving south out of Kentucky late in the
overnight hours. Confidence is medium that this will impact CSV,
but much lower confidence for other sites. Additional storms may
come down across the area Tuesday, but timing and coverage are
uncertain. Winds will be mainly SSW through the next 24 hours,
and mainly less than 10KT.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 73 94 73 94 / 20 40 30 10
Clarksville 74 95 72 95 / 20 30 30 10
Crossville 67 84 67 86 / 30 60 30 20
Columbia 71 95 71 95 / 10 40 40 20
Cookeville 68 86 69 89 / 50 50 30 20
Jamestown 67 83 68 86 / 70 50 20 20
Lawrenceburg 69 92 70 93 / 10 30 40 20
Murfreesboro 70 93 71 93 / 20 40 30 20
Waverly 72 95 72 95 / 10 30 30 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......JB Wright
SHORT TERM...21
LONG TERM....21
AVIATION.....13
Area Forecast Discussion
National Weather Service Paducah KY
717 PM CDT Mon Aug 1 2022
.UPDATE...
Issued at 717 PM CDT Mon Aug 1 2022
Updated aviation section for 00z TAF package issuance.
&&
.SHORT TERM...(Tonight through Wednesday night)
Issued at 250 PM CDT Mon Aug 1 2022
The atrocious humidity is back, with dew points 75 to 80 and heat
index values up to 105, or so from SEMO into southern IL and far
west KY. Values are not quite as high from southwest IN into the
KY Pennyrile. There is an area of enhanced CU from KIND west to
south of KSPI to KIRK. The suite of HREF HiRes guidance varies
somewhat. Some of the models develop convection and move it south,
to southwest across our area late today into tonight, becoming
cold pool and outflow dominant with time. The NAM and HRRR are not
as bullish on such a scenario, keeping the focus more on the
Evansville Tri-State region. We will carry slight chances a bit
farther west to account for some of the HiRes guidance. Such a
scenario is not uncommon in this setup. It is very unstable with
favorable mid level lapse rates, and decent effective bulk shear
over the northeast 1/2 of the region.
Convective chances will appear again Tuesday. Then we should see a
break Wednesday, with convective chances back in the forecast
Wednesday night as the unsettled pattern remains in place. We will
continue with our Heat Advisory as is, and a Special Weather
Statement elsewhere.
.LONG TERM...(Thursday through Monday)
Issued at 250 PM CDT Mon Aug 1 2022
Very humid conditions will persist into early next week. South to
southwest winds will continue to pump tropical humidity into our
region. The moisture-laden atmosphere will be prone to generating
locally heavy downpours in any convection. The highest chances for
storms will be on Thursday into Friday, when a weak surface boundary
may push as far south as the lower Ohio Valley and southeast
Missouri.
On Thursday and Friday, the 500 mb pattern will consist of a Bermuda
high and a Plains high. Between these two systems, a weak trough
will exist over the Ohio Valley area. This will help support
scattered thunderstorms near the weak surface front.
Over the weekend, the models still indicate the 500 mb high over the
Plains will strengthen and expand east across the mid and upper
Mississippi Valley. This upper-level high should reduce convective
coverage to just isolated across most of the area. Heat and humidity
will build back up, with heat indices topping 100 in the forecast
both days.
There is quite a bit of model variability for Monday. The general
model trend seems to be for the 500 mb high to retreat westward back
to the Plains. This would allow a little more northwest flow over
our region, along with a bit of an increase in convection and a bit
lower heat.
&&
.AVIATION...
Issued at 717 PM CDT Mon Aug 1 2022
Strong to severe tstms with gusts of 45-60kts possible through
03z at KEVV/KOWB. MVFR to LIFR conditions expected with storms.
Isolated activity expected after 03z with predominant VFR
conditions. At KCGI/KPAH/MVN, VFR conditions expected through the
TAF period. At all sites, winds will be from the south to
southwest at 5 to 10 mph.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...Heat Advisory until 8 PM CDT Wednesday for ILZ075-080-081-084-
085-088-092.
MO...Heat Advisory until 8 PM CDT Wednesday for MOZ076-086-087-100-
107>111.
IN...None.
KY...None.
&&
$$
AVIATION...RST
Area Forecast Discussion
National Weather Service Phoenix AZ
502 PM MST Mon Aug 1 2022
.UPDATE...Updated Aviation Discussion.
&&
.SYNOPSIS...
Sparse thunderstorm coverage will be the theme
through the middle of the week with activity more focused over
higher terrain areas. In response to lesser storm coverage,
temperatures are expected to warm back to near normal values,
resulting in a moderate heat risk for most of the lower desert
communities. A return to a more active monsoon storm pattern
still appears likely as we head towards the end of the week and
into the upcoming weekend.
&&
.DISCUSSION...
Latest water vapor satellite imagery as well as the 500 mb
streamline RAP analysis depict a strengthening subtropical high
pressure across New Mexico. The center of this high pressure is
expected to migrate into Arizona through the middle of the week,
resulting in subsidence aloft across the area with any easterly
wave action expected to remain south towards the international
border. With the increasing subsidence, some drier air will also
be mixing in with PWATs dropping to below 1.5 inches. As a result,
thunderstorm activity across the area is likely to be sparse with
any activity expected to be confined mainly to the higher terrain
areas.
With the expected decrease in storm coverage, temperatures are
expected to rebound to near normal levels through the middle of the
week with highs in the Phoenix area topping out between 104-106
degrees and between 105-109 degrees across the western deserts. In
addition, with surface dewpoints likely to remain in the 60s, it
will be rather humid as well making it for uncomfortable conditions,
especially at night. With this increase in temperatures, the
HeatRisk across most of the lower desert communities will increase
to moderate levels and thus the necessary precautions will need to
be taken to avoid any heat-related illnesses.
As we head towards the latter end of the week into next weekend, the
overall pattern will once again become more conducive for more
widespread thunderstorm activity. Ensembles are in excellent
agreement that the center of the aforementioned high pressure will
shift towards the Plains and Midwest while a cutoff low over the
eastern Pacific combines with the remnant circulation of Tropical
Storm Frank to form a stationary low off the west coast. This
pattern configuration will place the SW CONUS in deep southeast
flow, which will help pump in moisture resulting in an increase
in PWAT values above 1.7 inches as well as allow for the migration
of easterly wave energy into the area. Therefore, another active
thunderstorm period is likely during this time frame with all
monsoon thunderstorm hazards on the table. At this point in time,
it is difficult to pin point exactly which days are likely to be
the most active with activity as it will all be dependent on
mesoscale features that are difficult to predict this far in
advance.
&&
.AVIATION...Updated 2355Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Storm activity today over distant and high terrain is expected to
be isolated with outflows not currently forecast. However, if
outflows do materialize, KIWA would be the most likely site to
experience the wind shift although it would likely be weak. This
evening and tonight breezy W winds will continue before a later
than normal E switch around 12Z. Skies will be mostly clear with a
period of increased SCT-BKN decks AOA FL150 tonight before
thinning out again. An earlier than normal W switch is likely by
mid Tue morning.
Southeast California/Southwest Arizona including KIPL and KBLH:
There is potential for KIPL to be indirectly affected by
storms over the Baja and San Diego Mountains. But confidence in
the occurrence of outflow, let alone TSRA, at the airfield is too
low to reflect in the TAFs. Otherwise, expect SE winds to shift W
and become gusty with gusts upwards of 20-25 kts by 05-06Z.
For KBLH there is potential for storms over La Paz County to
affect the airfield, but confidence in the occurrence of outflow,
let alone TSRA, at the airfield is too low to include in the
TAFs. Otherwise, expect S winds to begin to favor the W by later
tonight. Skies will remain mostly mostly clear with FEW-SCT decks
AOA 15 kft.
&&
.FIRE WEATHER...
Somewhat drier air will spread into the region through the middle of
the week with thunderstorm and rainfall chances becoming more
focused over higher terrain areas of eastern districts. Eventually
by the end of the week, thunderstorms will migrate back into lower
elevations. Regardless, the fire threat will remain low given
elevated humidity levels and recent rainfall. Minimum humidity
levels will range mostly from 20-30%, except 30-40% over higher
terrain of eastern areas. Recovery will vary widely between 30-90%
depending on thunderstorm and rainfall locations any given day.
Winds will generally remain light with some occasional afternoon
upslope gusts, and stronger gusts resulting from thunderstorm
outflows.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Lojero/18
AVIATION...Sawtelle/AJ
FIRE WEATHER...18
Area Forecast Discussion
National Weather Service Tucson AZ
130 PM MST Mon Aug 1 2022
.SYNOPSIS...A fairly typical early monsoon pattern is expected
through Tuesday with scattered mainly afternoon and evening shower
and thunderstorm activity. A ramp-up to an above normal monsoon
pattern is expected later this week into the weekend.
&&
.DISCUSSION...Its been a bit of a slower start to convective
development today as the atmosphere is a bit worked over from
yesterday. However, with abundant sunshine and ample daytime
heating, we`re starting to see some development especially on the
Sky Islands to the south and east of Tucson. Latest RAP mesoanalysis
shows MLCAPE values of 1000-2000 J/kg with DCAPE around 1000 J/kg.
That`s certainly enough instability to work with, thus resulting in
scattered shower and thunderstorm activity through the afternoon and
into the evening. Latest CAMs depict this scenario fairly well with
storms pushing NW at about 15 mph in the southeast mid level
steering flow. Overall, it will be much more of a down day compared
to yesterday and more like a typical monsoon day.
With the mid-upper level high consolidating near the AZ/NM border
through Tuesday, we`ll be relying a bit more on recycled moisture on
Tuesday for storm development. With that said, the CAMs are in good
agreement on developing scattered convection on the higher terrain
to the south and east of Tucson and pushing west via light easterly
steering flow and outflow propagation. Best chances will remain from
Tucson south and eastward Tuesday afternoon and evening.
For the remainder of the week starting on Wednesday but particularly
by the end of the work week and into the weekend we`ll be settling
into a general above normal monsoon regime as the mid-upper level
high shifts eastward into the Plains. That will open us up to
easterly disturbances with near to above normal moisture levels
expected with perhaps an increased flash flooding threat given many
spots have seen considerable rain of late. We`ll see typical day-to-
day variability as usual but overall it will be an active period.
Temperatures will be near normal through the rest of this week.
&&
.AVIATION...Valid through 03/00z.
SCTD SHRA/TSRA with cloud bases at 7k-12k ft AGL thru 02/03z, then
generally diminishing overnight with another round of SCTD SHRA/TSRA
aft 02/19Z mainly from KTUS-KOLS eastward. CIGS can lower to 4k-7k
ft AGL with any precipitation, including gusty winds in excess of 40
kts. Otherwise, winds will follow diurnal trends and remain near or
below 10 kts. Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...Expect continued scattered shower and thunderstorm
activity this week. Strong and erratic outflow winds accompany
the stronger storms, with otherwise diurnal wind trends.
&&
.CLIMATE...Yesterday the Climate Prediction Center (CPC) released
their outlook for August for southeast Arizona. Precipitation is
leaning above normal while temperature is leaning below normal.
This is the first time since 2015 that the August temperature
outlook for SE AZ is leaning below normal.
Tucson climate stats for July:
7th warmest at 90.0F and 28th driest with 1.08". Per Pima County
Regional Flood Control District, most of the metro area recorded
more than the airport with totals between 1.50" to 3.50" with
locally higher amounts, showing the true nature of the monsoon.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
Lader
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