Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/22/22
AREA FORECAST DISCUSSION
National Weather Service Albany NY
954 PM EDT Sun Aug 21 2022
.SYNOPSIS...
An approaching upper level disturbance and frontal system will
bring increasing chances for showers and isolated thunderstorms
late tonight through Monday. Additional showers and thunderstorms
are possible Tuesday as the upper level disturbance moves through
the region. Fair weather returns for midweek, along with above
normal temperatures.
&&
.NEAR TERM /THROUGH MONDAY/...
Updated at 950 PM EDT. Scattered showers from Ohio eastward
across NY and PA appear to be holding together and even slightly
increasing in coverage during the past few hours as they
advance to the east-northeast. Scattered showers will be
increasing across the western and southern parts of our forecast
area after midnight as a weak wave of low pressure organizes
off the mid- Atlantic coast in response to a moderately strong
mid-level trough approaching from the Great Lakes. The latest
00z HRRR is still showing that most of the precipitation with
this wave will track across eastern and southern New England on
Monday with just scattered showers and thunderstorms for eastern
NY and western New England, however there remains considerable
spread in the CAMs forecasts on coverage and timing of rainfall.
Even scattered showers would bring localized heavy rainfall as
pwats will be between 1.5 and 2.0 inches with deep warm cloud
depths and with slow-moving storms. The models are also
indicating a weak (20-25 kt) low-level south- southeasterly jet
early on Monday across New England as the weak wave organizes,
which could also act to enhance rainfall in areas that can get
organized rainfall. Due to the dry conditions, any isolated 1
to 3 inch amounts that fall on Monday would be mainly just
beneficial.
Updated at 815 PM EDT. A mid-level trough associated with
multiple lines and clusters of showers continues to approach the
area from eastern Great Lakes this evening. A couple of lines
of showers on the eastern edge of this trough have already
dissipated earlier this evening as they approached our area
while moving east of the strongest mid- level forcing and
largest instability. Additional areas of showers over western
Pa and western NY will track east toward the area later tonight,
and these should hold together more efficiently as they will be
associated with stronger forcing as the trough moves east.
Expect showers to increase in coverage mainly south of I-90 and
west of the Hudson River after midnight tonight as the upper
trough approaches. An organized area of showers will likely
track across the the area south of I-90 and across southwest New
England Monday morning with 6 hour rainfall amounts around half
an inch in many areas as a weak wave of low-level low pressure
organizes over southeast NY and southwest New England. Farther
north rainfall should be lighter and spottier through Monday
morning. Previous discussion is below.
As of 350 PM EDT, cluster of showers and isolated thunderstorms
continues to track northeast across portions of the SW
Adirondacks. This should taper off over the next hour. Some
sprinkles from a mid level cloud deck continue across portions
of the eastern Catskills and Capital Region, and these may
persist for another couple of hours before dissipating.
Additional showers/thunderstorms are developing across central
NYS, in association with a weak low level differential heating
boundary remaining from earlier convection, and ahead of next
mid level disturbance across central PA. Most of these
showers/storms are expected to remain west of the region this
evening, however can not rule out a few rogue cells reaching far
northern Herkimer County.
The remainder of the region should be mainly dry through at
least midnight, before some showers possibly develop across the
eastern Catskills/mid Hudson Valley, as well as the SW
Adirondacks/western Mohawk Valley after midnight. A steadier
rain should develop by daybreak across the mid Hudson Valley and
extreme southeast Catskills, and may have some embedded
convective elements with heavier downpours.
Low temps mainly in the 60s overnight.
&&
.SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
Ahead of approaching mid level trough, isentropic lift will
increase across the region during the morning. This should allow
rain to overspread most areas south of I-90, although may take
some time upon reaching areas closer to, and especially north of
I-90 and east of I-87. Rain may be moderate to heavy at times
across the SE Catskills through the mid Hudson Valley and into
NW CT, possibly as far north as the southern Berkshires during
the morning hours, with some rumbles of thunder possible.
Rainfall rates could approach/exceed 0.25-0.50/hour in some of
these areas. Farther north, confidence is less regarding overall
rainfall intensity and amounts, as there remains a possibility
that best low level forcing from convergence and elevated
instability remains across southern areas, while better upper
level dynamics remain to our west, resulting in reduced coverage
and intensity of showers for areas north and east of Albany.
Best chances for these areas to receive rainfall may not be
until the afternoon hours, with the approach of better dynamics
from the west. Max temps are also questionable for Monday, with
some guidance suggesting highs only in the 60s to lower 70s. For
now, have sided very close to the warmer NBM (yielding 75-80 in
valleys, and upper 60s to lower 70s across higher terrain),
assuming there will be at least some breaks in the rainfall
during the day.
Showers should taper off Monday night, with areas of fog
potentially forming.
Tuesday could be a more convectively active day, as the main
upper level trough/cold pool move through, along with a slow
moving cold/occluded front. Models suggest MU CAPES build to
500-1000 J/kg from Albany north and west, and to 1000-2000 J/kg
to the south and east. Overall mid level winds remain weak,
although 0-6 km shear is a bit stronger south and east of Albany
(20-25 KT). It is this area, generally south and east of Albany,
where isolated stronger thunderstorms may exist, and trends will
need to be watched. High temperatures generally reaching the mid
70s to lower/mid 80s.
Lingering showers/thunderstorms Tuesday evening, then clearing
with patchy fog developing later Tuesday night, with lows in the
upper 50s to mid 60s.
&&
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
The mid-level long-wave pattern during the second half of this week
will feature westerly flow over the northeast CONUS around the south
side of mid-level low pressure anchored over northeast Canada. The
mid-level trough that will bring unsettled weather early this weak
will be pushing east of the area, setting the stage for a return to
mainly dry, warm conditions through the second half of the week. Any
short-waves that track east across the region through this period
will be weak and difficult to time, but at this point the best
chance for a round of showers and thunderstorms looks to be on
Friday. Bermuda high pressure may build back toward the eastern
CONUS next weekend, bringing another round of unseasonably warm
weather.
Based on this scenario, we have high temperatures mainly in the 80s
from Wednesday through Saturday, with lows in the mid 50s to mid
60s. Pops will be below climo, with highest values around 30 to 40
percent on Friday with the possible passage of a short wave trough.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
Conditions are currently VFR at all terminals with FEW/BKN
layers in the mid and upper levels, and unrestricted vsbys. An
increase in cloud density and a lowering of cloud bases can be
expected through 00Z Tuesday ahead of an approaching low
pressure system. Showers of varying magnitudes and durations are
projected to begin prior to 16Z at KPOU and KPSF and after 16Z
at KGFL and KALB. Showers will likely begin with VFR cigs and
vsbys, but could degrade to MVFR. The highest likely for
heavier precipitation will be to the south at POU where IFR
vsbys and cigs are possible between 13Z and 17Z.
Winds are currently 5 kt and variable at KPOU and KPSF, and
lighter out of the south at KGFL. KALB is experiencing 10 kt
winds out of the southeast with a 16kt gust. Winds look to
remain out of the south and southeast for all terminals
throughout the night tonight. KALB will experience more moderate
speeds of close to 10 while KGFL/KPOU/KPSF will experience
lighter winds. Gusts throughout the day tomorrow will range from
10 to 15 kts starting at 16Z as the low pressure system moves
through our area.
Outlook...
Monday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Tuesday: High Operational Impact. Likely SHRA...TSRA.
Tuesday Night: Moderate Operational Impact. Chance of SHRA...TSRA.
Wednesday: Low Operational Impact. NO SIG WX.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Moderate Operational Impact. Chance of SHRA...TSRA.
&&
.HYDROLOGY...
A period of moderate to heavy rain is possible across portions
of the SE Catskills, mid Hudson Valley, NW CT, and the southern
Berkshires Monday, especially during the morning. Rainfall rates
of 0.25-0.50/hour are possible, with locally higher rates
possible within any thunderstorms. This could lead to some
ponding of water in urban/poor drainage areas.
Total rainfall amounts through Tuesday of could reach 1-1.5
inches across some southern portions of the region, while
northern areas (upper Hudson Valley and southern VT) generally
receive 0.25-0.50 inches. Locally higher amounts will be
possible where thunderstorms occur. This rain will be highly
beneficial due to overall worsening drought conditions across
portions of the region.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...KL
NEAR TERM...MSE/KL
SHORT TERM...KL
LONG TERM...MSE
AVIATION...MSE/Gant
FIRE WEATHER...
HYDROLOGY...
Area Forecast Discussion
National Weather Service Cleveland OH
957 PM EDT Sun Aug 21 2022
.SYNOPSIS...
A slow moving low pressure system will move to the eastern Great
Lakes through Monday and maintain an unsettled weather pattern. High
pressure will build overhead through the mid-week period. The next
trough will approach from the north by Friday.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
Very heavy rain continues along the lakeshore from Geauga County
through eastern Lake County, Ashtabula County, into Erie. The
storms have been producing rainfall amounts between 1 and 2
inches an hour based on ground observations. Locally higher
amounts occurring in the heaviest rain. Activity is expected to
move slowly northeast out of the area. Another round of showers
continues to rotate southeast out of Michigan in a weakened
state at this time. Short term models suggest this band will
move southeast across Lake Erie and produce more showers and
thunderstorms over the northeast overnight. Will have to monitor
trends due to ongoing flooding across the area. Otherwise,
patchy dense fog is expected across the area during the night.
Previous Discussion...
Surface analysis has a broad 1015mb low extending across eastern
Indiana/western Ohio with an upper level low nearly vertically
stacked overhead. Sufficient clearing earlier this afternoon allowed
the airmass to destabilize with ML CAPE values of around 1500 J/kg.
However convection over Central Ohio has produced a lot of cirrus
debris which has limited further destabilization across central
Ohio. Convection continues to fill-in across NW Ohio and closer to
the lakeshore and will continue to shift east through the evening.
In addition, the HRRR suggests additional convection will fill in
across SW Ohio where heating continues and may drift towards the
Central Highlands with time. As the upper trough continues to slowly
pivot eastward tonight, storm motion will continue to the
northeast. The one area where pops may end up being to high
could be across inland NE Ohio but will adjust with future
updates as needed. Broad rotation associated with the upper
level system, especially co-located near the better surface
convergence, has led to the development of several funnel clouds
in NW Ohio. While funnel clouds may occur, the overall tornado
threat remains low given the lack of stronger shear and storm
organization. Thunderstorms have maintained a relatively low
centroid making heavy rain a concern, especially where training
occurs with southwest to northeast storm motion. Pockets of
rainfall in excess of 2 inches is possible and flood products
may be needed, especially where heavy rain has occurred over the
last 24 hours. Will continue to monitor severe weather
potential but the threat remains fairly isolated given effective
shear values of only 20-30 knots. Most likely case would be if
a storm with a stronger core collapses.
Coverage of precipitation will decrease considerably as we move past
peak heating and mid-level dry-slot wraps in from the west. Where
breaks develop in the clouds overnight, patchy fog may develop with
light winds and a moist boundary layer. As the 850-700mb trough
pivots across eastern Lakes Erie towards dawn, we expect to see lake
enhanced showers move in off the lake. Fairly good coverage is
expected across the eastern forecast area again on Monday, with
coverage increasing with daytime heating. Both temperatures and
instability will be a little lower with the cooler airmass overhead
on Monday. Chances for showers will become increasingly confined to
just off the far east end of Lake Erie on Monday night.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Upper level trough moves eastward very slowly through Wednesday
night. A surface trough should linger over/near Lake Erie through at
least Wednesday morning. This may assist with shower/thunderstorm
development through Tuesday afternoon, especially across the
eastern half of the CWA. Models then attempt to move everything
eastward with the upper level trough. Still slightly concerned we
will add some rain chances to Wednesday with later updates as some
jet energy moves across southern Ontario.
Temperatures look to be near seasonal averages through the short
term period.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
A broad surface trough will linger over the area through Friday
night as a surface high pressure gradually shift southeast. On
Friday, a weak cold front associated with a low pressure near the
Gulf of St. Lawrence is forecast to move southeast across. This
boundary will bring a brief chance of precipitation, unless it
stalls across the area. Opted to maintain a front that stalls to the
southeast of the area for now, keeping chance PoPs in the forecast.
There is a non-zero chance of thunder with this system, although it
will be highly dependent on instability developing and any upper
level support present. Late Friday into Saturday, an upper level
ridge, and associated surface high pressure, will build over over
the Eastern U.S. and persist through the remainder of the period. On
Sunday, an increase in southerly winds will mark an increase in high
temperatures, reaching into the mid 80s, which is expected to be the
warmest day for the period. Dewpoints on Saturday and Sunday will
climb into the low to mid 60s, marking a return of humid, muggy
conditions across the area.
&&
.AVIATION /00Z Monday THROUGH Friday/...
Thunderstorms with locally heavy rain across the area continue
to move east across the region. Expecting activity to be
scattered in nature with a possible round moving into the area
later tonight. Then, as day time heating picks up again
tomorrow, expecting more showers and thunderstorms to develop
again. Ceilings will be on the low side overnight down to IFR
and visibilities down to IFR/MVFR at times due to fog developing
across the area. Winds should be light through the period.
Outlook...Non-VFR possible with scattered rain showers and
thunderstorms through early Tuesday, with the best chance
Saturday afternoon through Monday.
&&
.MARINE...
Low pressure is expected to track eastward near the south shore of
the lake tonight into Monday morning. In the lows wake a cold front
crosses the lake with winds becoming northwest to north. Speeds
generally remain under 15 knots which typically wont build waves
above the 2 to 4 foot range. These northerly winds persist into
Monday night with maybe a slight increase in the speed. A short
small craft advisory may be needed Monday evening into the
overnight. Will definitely need to mention a moderate risk of rip
currents in the HWO for a decent portion of the lake east of the
Islands Monday into Monday night. Will also need to monitor for
waterspouts along the frontal boundary.
A surface trough then lingers on/near the lake into Wednesday. Just
cool enough air aloft and the convergence along the trough axis may
be enough to produce some waterspouts. Confidence not as high with
this potential to mention in the forecast at this time. If
conditions look more favorable over the next couple days we will add
them.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...KEC
NEAR TERM...KEC/Lombardy
SHORT TERM...MM
LONG TERM...Campbell
AVIATION...Lombardy
MARINE...MM
Area Forecast Discussion
National Weather Service Cheyenne WY
445 PM MDT Sun Aug 21 2022
.SHORT TERM...(This evening through Monday)
Issued at 201 PM MDT Sun Aug 21 2022
Isolated showers and thunderstorms have developed in far southern
Wyoming in the Sierra Madre and Snowy ranges near the Colorado
border. PWAT values in the 0.8-0.9 inch range have fueled a few
briefly heavy downpours, however morning cloud cover ultimately
stemmed any stronger instability from developing. Another boundary,
noted on visible satellite imagery over Laramie county, has made a
few attempts at firing a convective shower or two and this trend may
continue over the next few hours. However, most CAM guidance
including latest HRRR runs indicates a rapid downtrend in any
activity in southeast Wyoming soon after sunset. Overnight, expect
partly to mostly clear skies with lows running near or perhaps a
degree or two below average.
Broad, weak northerly flow will push lingering elevated PWAT
values south and east on Monday. An isolated shower remains a
possibility in the higher terrain of the Sierra Madre and
Snowies, however even the more bullish HREF members still keep
this activity quite limited. Expect a mainly dry day with
afternoon highs near climatological average for late August.
.LONG TERM...(Monday night through Sunday)
Issued at 201 PM MDT Sun Aug 21 2022
Increasing activity in the long term forecast with precipitation
chances climbing towards the end of the week.
On Tuesday, models show a weak upper level low tucking underneath
the broad ridge covering much of the western half of North America.
It looks likely that this feature will cutoff from the flow aloft
over Washington and then slowly meander eastward through the
remainder of the week. Precipitable water reach their minimum for
the week on Tuesday as a jet streak over the southern Plains helps
to divert much of the monsoon moisture eastward into Texas. A few
storms may develop over the higher terrain but convection should be
fairly isolated Tuesday. A subtle area of 500-mb vorticity rotating
around the cutoff low will pass to our north, and could provide
enough lift to initiate convection across the northern counties too.
This is reflected with 15-30% PoPs introduced for Converse county
eastward to Dawes county. Wednesday looks similar with fairly low
moisture content over our southern counties, but building moisture
to the north. Thus, continuing a chance for isolated storms in the
mountains, but this could need to be decreased with later updates.
Temperatures on Tuesday and Wednesday look generally near to
slightly above average for late August.
The main upper level low nears our area on Thursday and Friday,
bringing the best chance for storm activity of the week. The flow
aloft turns weakly WSW, and fills in better moisture over much of
the area. The GEFS and ECMWF ensembles show a mean PW of around 0.9
inches over KCYS by 00z Friday before starting to gradually decrease
again. Models differ somewhat on the low level moisture availability
and flow. The GFS depicts a 700-mb anticyclone setting up Thursday
over Kansas which would help to advect in improved moisture and
southerly low level winds, but this is not yet a consensus position.
Regardless, with the higher precipitable water and enhanced lift
associated with the passing shortwave, expecting more widespread
shower and storm activity both Thursday and Friday. Confidence is
higher in SE Wyoming, where over 75% of major ensemble members have
some precip at KCYS both days. Lesser confidence in the Nebraska
panhandle but still have higher PoPs for the entire CWA both days.
Forecast uncertainty increases dramatically for the weekend with a
large spread in the ensembles developing. The deterministic ECMWF is
a bit of an outlier right now in showing a stronger shortwave diving
further south to pass directly over the CWA and bring more
widespread stratiform precipitation to the area, but the period
bears watching nonetheless. Ensemble mean 500-mb heights are
generally below normal for the weekend, but start to climb above
normal again for the early part of next week, outside of the
operational period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 445 PM MDT Sun Aug 21 2022
Prevailing VFR. A few showers may develop in the vicinity of KCYS
until 02Z, otherwise no weather impacts are expected. Mostly cloudy
skies this evening will become mostly clear overnight. Surface wind
directions will vary from southerly to southwesterly with speeds
less than 10 kt.
&&
.FIRE WEATHER...
Issued at 201 PM MDT Sun Aug 21 2022
Dry and warm weather will continue across much of east-central
Wyoming from now through early next week. Afternoon RH values will
approach 15% in Converse and Carbon Counties. Wind speeds however will
remain generally light and below 20 mph even during peak afternoon
heating. A return of moisture will arrive on Thursday and Friday of this
coming week. Scattered afternoon storms are likely which could bring
instances of wetting rains over a large portion of southeast WY and W NE.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...MAC
LONG TERM...MN
AVIATION...MAJ
FIRE WEATHER...MAC
Area Forecast Discussion
National Weather Service Green Bay WI
625 PM CDT Sun Aug 21 2022
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 235 PM CDT Sun Aug 21 2022
The latest RAP analysis and satellite/radar imagery show upper
level low pressure exiting across Michigan early this afternoon.
Meanwhile, high pressure was centered across the northern
Mississippi Valley. Back edge of the clearing line has steadily
been progressing south across central and northeast Wisconsin,
and is approaching areas from Green Bay to Clintonville at 2 pm.
Shallow fair weather cu exists further northwest closer to the
surface high where dewpoints are dropping into the 50s. Forecast
concerns mainly revolve around fog potential tonight, followed by
temps.
Tonight...High pressure will become centered across the region.
Any lingering shallow cu should dissipate early this evening,
which will leave clear conditions and light winds. These
conditions will promote fog development, similar to what occurred
over Minnesota this morning. Statistical guidance favors central
and north-central WI for the greatest potential, while ensemble
guidance favors east-central WI where cross-over temps remain
high. Either way, will show patchy to areas of fog across the
region. Locally dense fog is possible. Cooler lows ranging from
the mid-40s to upper 50s.
Monday...High pressure will remain across the region resulting in
mostly sunny skies with fair weather cu developing with the heat
of the day. High temps ranging from the upper 70s to the lower
80s.
.LONG TERM...Monday Night Through Sunday
Issued at 235 PM CDT Sun Aug 21 2022
NW flow regime will continue through the middle of the week, then
transition to a baggy WSW flow by the end of the week. Any
embedded disturbances within this flow regime will be
underwhelming, accompanied by overall weak wind fields and weak
deep layer shear. The next opportunity for a more substantial
system to impact the area will likely not be until this weekend.
First weak short wave disturbance and accompanying weak surface
frontal boundary to impact the forecast area looks to be Tuesday
afternoon into the early evening. Positively tilted shortwave is
forecast to drop southeast across the forecast area while a weak
W-E orientated surface boundary will be located somewhere across
northern Wisconsin by 7pm Tuesday. There appears to be sufficient
low-level convergence and mean instability on the order of 1000
J/kg to continue low-end chance pops north of Highway 64 where an
isolated shower or thunderstorm could develop. NAMNest forecast
soundings indicate very weak winds up through 9km and long skinny
CAPEs of ~ 500 J/Kg, thus anything that can develop would be
pulse-like, slow-moving and a relatively efficient rainfall
producer. Any isolated activity that does form could persist for
an hour or two after sunset.
Weak surface frontal boundary hangs around during the day on
Wednesday as well with the NAM, GFS and ECMWF suggesting boundary
will be most likely positioned somewhere along the I29 corridor by
21Z Wednesday. Medium range guidance seems to suggest a greater
discrepancy in the amount of instability along and south of the
frontal boundary. NAM suggests MLCAPEs around 1500 J/kg, while the
GFS closer to 500 to 750 J/kg. Given NAM has a tendency to be too
high on surface Tds, prefer the much more conservative GFS in
this regard. Although, upper-level support seems to be quite weak,
boundary layer convergence looks fairly substantial especially
over far NE and EC Wisconsin, where some enhancement by an
afternoon lake breeze may also be in play. Convective initiation
and propagation will likely be strongly modulated by low-level
forcing/boundary interactions. This seems to be supported by
somewhat higher POPs and QPF in this part of the forecast area
late Wednesday afternoon and early evening via the GFS/NAM. For
now, opted not to get cute with details this far out and just go
with the model blend POP and QPF for Wednesday afternoon. Given
somewhat higher available moisture, instability and more focused
boundary layer convergence, shower and thunderstorm activity will
be somewhat more widespread Wednesday afternoon. Again, with weak
wind fields and long/skinny CAPEs, precipitation efficiency looks
pretty good. Another weak and transient impulse will also quickly
traverse the area Wednesday night, thus scattered shower and
isolated thunderstorm activity will likely persist for much of
Wednesday night.
High pressure will become re-established over the forecast area
for Thursday into next weekend with temperatures near normal for
the later part of August. The next chance for measurable
precipitation does not appear to be until Sunday afternoon.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 618 PM CDT Sun Aug 21 2022
The potential for FG/ST is once again the main aviation weather
concern. Plenty of sunshine and mixing allowed Tds over C/N-C WI
to drop off during the aftn, though probably not enough to
prevent FG/ST overnight. Low-level moisture was not able to mix
out in E-C WI, as Tds were still in the 60sF. Conditions seem more
favorable for fog tonight (as opposed to last night when ST was
favored). Handled similar to the 18Z TAFs in the west, but was a
little more aggressive with FG development in the east. Did not
include any VLIFR conditions with the 00Z issuance, but it is
possible a TEMPO group for those might be needed with the next
issuance. Want to see the specifics of how temps and dew points
react after sunset before making a decision on that.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM.....MPC
LONG TERM......ESB
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1019 PM EDT Sun Aug 21 2022
LATEST UPDATE...
Update
.UPDATE...
Issued at 1019 PM EDT Sun Aug 21 2022
Now that the scattered showers and storms have dissipated with
loss of sfc heating, attention turns to fog potential overnight.
While the sfc winds have become light or calm, The RAP 925mb winds
remain higher through the night at around 10-15 kts.
Typically in a situation like this a low stratus deck and lighter
fog is a more likely outcome than having dense fog. HiRes
guidance consensus is for a low cloud deck to develop south and
east of GRR after 3-4 AM and linger through 8-9AM. However with
the currently elevated sfc dew points in the mid 60s and recent
rains will keep patchy fog in the fcst late tonight/early Monday.
The Beach Hazard Statement and Small Craft Advisory have been
working out very well as the Port Sheldon and South Haven buoys
have recently peaked near 4 feet. Meanwhile winds have diminished
to around 10 kts up at Big Sable Point. Will maintain the
headlines through 5 AM from Grand haven southward but have
recently let the headlines expire north of Grand Haven where
diminishing trend is occurring.
&&
.DISCUSSION...(This evening through next Sunday)
Issued at 346 PM EDT Sun Aug 21 2022
- Showers and Thunderstorms into this evening
We expect showers and a few thunderstorms (not severe) into this
evening as a cold front slowly slides south across the area.
There is very little effective bulk shear, but we have decent
surface convergence thanks to both the front moving through the
area and the cold air making better progress over Lake Michigan
than over land. There is around 1500 j/kg of mix layer cape to
work with and the air is very moist up to near 250 mb. This means
slow moving wet storms. The area getting the showers will be
mostly near and west of US-131 into later afternoon then as
evening wears on, the area of convergence is expected to move
inland. By late evening there may still be a few storms near
US-127. This should all come to an end by midnight.
- Some fog possible toward Monday morning
The combination of a weak front and clearing skies after 2 days of
significant rainfall will lead to areas of fog Monday morning.
Some of the high res models have areas of dense fog near and west
of US-131 (where the afternoon convection today has been and is
expected to continue to be into early evening).
- Monday should see a fair amount of sunshine
With the surface high building in from the northwest and the mid
level jet axis close to us but west of us, we stay in the cooler
air Monday. That will allow for some convection over the eastern
CWA Monday and puffy cumulus clouds elsewhere Monday.
- Tranquil Weather into Thursday
A rather powerful storm over northern Hudson Bay rotates around
itself most of this week. Over time the upper level circulation
around this system gets larger. By Thursday it should be just
large enough to push a cold front into our area. The air behind
this front is very cold, there was snow at Resolute Bay from this
system. The air cold enough to snow gets down to central Hudson
Bay by midweek. Not to worry through, the polar jet the hold this
air does not get this far south so we will not get into the really
cold air just yet!
Nonetheless, we do get the surface cold front and it would not be
out of the question to see some convection on the front Thursday.
However with the polar jet in Canada there would not be a lot of
dynamics for this front so any convection would likely be
isolated and weak.
- Next significant rain event early next week
Eventually a strong enough Pacific system comes on shore over
Western Canada and pushes that other system toward Europe. That
brings in a digging shortwave for the Great Lakes. That would tap
Gulf moisture by Monday into Tuesday and bring another several
day rain event for us. Likely we would have thunderstorms with
locally heavy rain and warm up but still I do not see highs much
warmer than the mid 80s, even so.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 759 PM EDT Sun Aug 21 2022
Scattered showers and isolated thunderstorms ending by midnight
otherwise VFR prevailing through 06Z. Areas of fog/stratus
possible late tonight, with a 3-4 hr period of LIFR cigs possible
09z-13Z -- mainly south and east of GRR. VFR expected Monday
after any fog/stratus lifts although can`t rule out an isolated
shower or tstm around LAN/JXN after 18Z.
&&
.MARINE...
Issued at 346 PM EDT Sun Aug 21 2022
We are still expecting the cold air moving in behind the front to
bring stronger winds and larger waves the near shore late this
afternoon into early tonight so we are holding on to our Beach
Hazard and Small Craft Advisory. We have a secondary, similar
event by a little weaker Monday afternoon as the drier air finally
moves in.
Late in the week, behind that Canadian cold front we may get
another one of these events with an advancing high causing higher
winds and waves.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 5 AM EDT Monday for MIZ056-064-071.
LM...Small Craft Advisory until 5 AM EDT Monday for LMZ844>846.
&&
$$
UPDATE...Meade
DISCUSSION...WDM
AVIATION...Meade
MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
743 PM CDT Sun Aug 21 2022
.SYNOPSIS...
Issued at 155 PM CDT Sun Aug 21 2022
Quiet weather is expected through much of this week as a
seasonably warm but otherwise dry airmass settles over the
Midwest and Great Lakes regions. The next best chance for
widespread rain comes late next weekend as conditions become more
humid ahead of a frontal system.
&&
.UPDATE...
Issued at 743 PM CDT Sun Aug 21 2022
Isolated showers that had been dropping southward across eastern
Illinois have been fading early this evening, and scattered
clouds are also diminishing. Main focus overnight will be with fog
potential again. Latest high-res visibility guidance has been
focusing on a narrower corridor from Rockford to Bloomington for
dense fog potential, in line with the higher probabilities shown
on the midday HREF. RAP and GFS soundings for Bloomington would
suggest more of a ground fog issue, though the NAM shows a fairly
moist layer up to 5,000 feet. Will keep the fog mention going for
areas north of I-72 overnight. Temperatures currently appear on
track to drop into the lower 60s by sunrise.
&&
.SHORT TERM...(This evening through Monday)
ISSUED AT 155 PM CDT Sun Aug 21 2022
Areas of dense fog will again be a concern tonight as skies clear
and winds turn light beneath high pressure. Latest HREF guidance
exhibits a 40-60% chance of fog below a 1/2 mile. While the model
seems to emphasize locations along and north of I-74, its quite
possible for patchy dense fog to develop in other portions across
central Illinois. Regardless, the fog signal appears to mix away
by 15z Monday morning with the onset of diurnal heating.
&&
Temperatures on Monday will warm into the low 80s beneath mostly
sunny skies. Overnight lows will cool to around 60 degrees.
.LONG TERM...(Tuesday through Sunday)
ISSUED AT 155 PM CDT Sun Aug 21 2022
A relatively benign forecast is in place through midweek as a
broad ridge of high pressure works to pacify thunderstorm
activity. A slight chance (< 20%) for showers and thunderstorms
returns to the forecast Thursday into Friday as a mid-level
shortwave trough and its attendant speed max clip the southern
fringes of the Hudson Bay and help drive a surface cold front
through the Great Lakes region. This front is expected to sag
south into central Illinois and wash out by Friday as the upper-
level kinematics and forcing become displaced too far east. While
this boundary, in theory, could become the focus for isolated
showers and thunderstorms, we`d like to see moisture and
instability progs edge higher. The better chance for widespread
showers and thunderstorms comes Sunday or Monday of next week as a
frontal system lifts across the region.
Temperatures this week will be seasonably hot with highs in the
low 80s Monday and Tuesday. Slightly warmer readings (mid 80s)
are then anticipated Wednesday and Thursday as surface high
pressure departs and winds veer southerly. The weekend could then
feature upper 80s as heat and humidity build ahead of the next
frontal system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 609 PM CDT Sun Aug 21 2022
Main aviation concern will be with potential IFR conditions late
night and early Monday morning. Latest guidance shows a widespread
expansion of lower visibilities after 09Z, though maybe not quite
to the extent that occurred this morning. Will hit the
visibilities a little harder in the new TAF set and bring them
down to about a mile toward early morning at KPIA/KSPI/KBMI.
Influence of a weak lake breeze this afternoon further east may
work in KDEC/KCMI`s favor, and will keep them at MVFR as before.
Rapid improvement expected by 13-14Z, with VFR conditions
prevailing the balance of the forecast period.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Geelhart
SYNOPSIS...MJA
SHORT TERM...MJA
LONG TERM...MJA
AVIATION...Geelhart
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1100 PM EDT Sun Aug 21 2022
.UPDATE...
Issued at 1100 PM EDT SUN AUG 21 2022
Just a few scattered showers and potential thunderstorms around
currently, but with instability now flagging any of the storms
should not be able to get too strong. Have updated the forecast to
fine tune the PoPs per the current radar and CAMs guidance through
the rest of the night. Did also include the latest obs and trends
for the T/Td grids. These updates have been sent to the NDFD and
web servers along with a freshening of the zones, SAFs, and HWO.
UPDATE Issued at 740 PM EDT SUN AUG 21 2022
23Z sfc analysis shows a cold front pressing into Kentucky from
the northwest and this is prompting scattered showers and
thunderstorms throughout the state. Locally, earlier cirrus clouds
kept instability in check for much of eastern Kentucky with a
current convective minima through the JKL CWA. Even so, several
storms are heading this way from central Kentucky and conditions
are favorable for new spawns downstream - likely driven by
outflows from earlier storms as well as the cold front`s approach
- through the evening. A few of these could still be rather
strong. Otherwise, temperatures are fairly uniform in the low and
mid 70s while dewpoints are around 70 degrees - fueling continued
concerns for heavy rains and a threat for storms. Away from any
storms, winds have been mainly light from the southwest. Did
update the forecast primarily to include the latest radar and CAMs
trends for the PoPs and storm chances, as well as to incorporate
the current obs and trends for the T/Td grids. These updates have
been sent to the NDFD and web servers.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 455 PM EDT SUN AUG 21 2022
Late this afternoon, an upper level low was located just east of
James Bay with a trailing 500 mb trough axis south into the Lower
OH Valley to the Ozarks to portions of the southern Plains while
ridging encompassed much of the western Conus and another ridge
was centered near Bermuda. At the sfc, an area of low pressure was
tracking across the Lower Great Lakes region while a cold front
trailing southwest to western KY and then west toward the Ozarks
and became nearly stationary west to portions of the Plains to
the lee of the Rockies. 20Z SPC Mesoanalysis reveals MLCAPE
generally in the 1250 to 1500 J/KG range across much of eastern KY
with slightly higher values in the Lake Cumberland Region and
across the far north and northeast. Mid level lapse rates are also
quite marginal to modest at 5.5 to 6.5 C/km with the higher
values across the southeast portion of the CWA. Low level lapse
rates are somewhat steep near 7 C/km on average across the area.
Effective shear was also on the marginal side in the 20 to 30KT
range in general. Stronger convection that has moved toward the
Lake Cumberland region has weakened as it neared or enter the CWA
with some stronger storms also having moved near the Big South
Fork region. The extensive cirrus that has been over the region
has generally limited instability and convection coverage and
intensity so far.
As the evening progresses, the better mid level lapse rates
though only marginal will shift east of the region over the next 2
to 3 hours per RAP with the rather steep low level lapse rates
also fleeting as the evening progresses as we pass peak solar
insolation with effective shear remaining marginal. UH
probabilities from the 12Z HREF also decrease with eastward extent
into the CWA this evening. The axis of the 500 mb trough will
shift east across eastern KY this evening with the axis of this
trough moving east of the area overnight. The Sfc cold front will
be slower to move east and should only near the western portion of
the CWA toward dawn. The potential for strong to perhaps locally
severe thunderstorms looks to only linger through about sunset and
then diminish significantly thereafter with the loss of daytime
heating, especially considering the sfc front hangs back well to
the west. Chances for convection should drop off markedly toward
midnight.
The axis of the 500 mb trough will be east of the region in
general on Monday, though a shortwave or two in northwest flow
should also cross the region. At the same time, the sfc cold front
will cross the area during the morning to mid afternoon timeframe.
Near this boundary, isolated to scattered showers and a few
thunderstorms are possible on Monday. Weak high pressure at the
sfc will build build in behind this boundary. This should set the
stage for some valley fog with clearing skies and light winds that
may be quite extensive and possibly dense in some places on
Monday night.
.LONG TERM...(Tuesday through Sunday)
Issued at 439 PM EDT SUN AUG 21 2022
An upper level trough will be in place across much of the eastern
Conus to start the period, with a secondary trough/upper level low
located across the southeast Conus. This general troughiness will
remain in place into the first part of the weekend, as the upper
level low and large-scale troughing finally begin to shift eastward
and out of the Conus. However, another upper level low and longwave
troughing will begin to impact the Pacific Northwest and Alaska,
bringing lowering heights and a series of upper level shortwaves to
the western Conus for the second half of the weekend - just outside
of the forecast period.
As for sensible weather, the frontal boundary that impacted us today
into Monday will have shifted southeast of the state by Tuesday. So
while upper level troughing is still in place, high pressure will be
in charge at the surface. Models are all in pretty good agreement
that pops should remain out of the state through Wednesday thanks to
the surface subsidence. However, an abundant amount of moisture will
be in place across the Deep South and Mid-Atlantic states, as the
surface boundary will remain in place here. There is some question
on Thursday afternoon and again on Friday afternoon if moisture will
be able to expand far enough northward to infiltrate the southern
part of the Commonwealth. There is still some uncertainty on this,
so keeping with the NBM at this point which does bring isolated to
scattered activity during the afternoon and early evening hours
Thursday, and more isolated activity in the same locations for
Friday. A secondary cold front is analyzed by WPC to push southward
across the Ohio Valley on Saturday, making its way towards the state
during the day. Despite this, the pops of the GFS seem to continue
to follow consistency from the previous two days, only expanding
into the southeast portion of the state during the afternoon and
early evening hours. The ECMWF seems to be a bit more liberal with
the precip chances across the state in comparison. Again, given then
is Day 7, went ahead and stuck with the NBM - which seems to favor
more of the GFS solution at this point.
Temperatures should be fairly steady state through the period,
without any major changes in airmass expected. Highs should
generally top out in the mid and upper 80s. Humidity doesn`t seem to
be playing a major role given the generally northern to eastern flow
throughout much of the period, so heat indices are not much higher
than the daytime highs. The same pattern will be applied to the
lows, as temperatures are expected to bottom out in the low 60s
through much of the period, with the exceptions of any ridge/valley
splits that may develop.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 820 PM EDT SUN AUG 21 2022
VFR conditions were reported at issuance time and mainly VFR CIGs
are expected to prevail during the first 6 or so hours - outside
of convection. Within convection, though, MVFR to IFR and briefly
lower conditions are anticipated. Some wind gusts up to around 30
kts could also occur if a thunderstorm directly impacts a
location. Chances for showers and thunderstorms should persist
during the first 3 to 6 hours of the period ahead of a shortwave
trough and a cold front. However, chances for rain will decrease
from west to east thereafter as the 500 mb trough axis moves past.
Late tonight, after 06Z, conditions are expected to deteriorate
through the MVFR range to IFR and perhaps even lower and remain
mostly IFR through 14Z or so, before gradual improvement into the
MVFR and VFR ranges later Monday. Winds will be light and variable
away from storms through Monday morning before picking up from the
northwest at 5 to 10 kts by midday.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...JP
LONG TERM...JMW
AVIATION...JP/GREIF
evening. Please refer to the previous forecast discussion for more
details on this week`s weather. -Miles
&&
.AVIATION...22/00Z TAFs...VFR weather inland through Monday evening,
with scattered cumulus buildups this evening from Siskiyou County
northeastward into Klamath and Lake counties.
At the coast, patches of LIFR/IFR early this evening will expand in
coverage overnight into Monday morning, and extend into the Coquille
Valley. Ceilings will lift and dissipate, and visibilities will
improve during Monday morning, though with areas of MVFR likely to
persist into Monday afternoon. -DW
&&
.MARINE...Updated 830 PM PDT Sunday 21 August 2022...Fairly benign
marine conditions area expected through Monday. Have decent
confidence in the idea of a strengthening thermal trough bring
increased winds and seas south of Cape Blanco Tuesday afternoon and
evening. Looks like a low end chance of gales in this period.
Similar conditions continue Wednesday and Thursday but with winds
and seas just a little bit lower. On Friday and Saturday, winds and
seas build again into stronger small craft advisory conditions with
some low-end gales possible, again only south of Cape Blanco.
-Stavish/DW
&&
.FIRE WEATHER...Updated 230 PM PDT Sunday 21 August 2022...An
incoming trough will bring gusty west winds to the ridges and
east side today and Monday. No thunderstorms are expected through
next Sunday, but hot and dry conditions will persist.
-Stockton
&&
PREV DISCUSSION... /Issued 256 PM PDT Sun Aug 21 2022/
DISCUSSION...
The weather pattern remains rather typical for mid to late August
across southern Oregon and northern California. The most notable
feature on satellite this afternoon is the slow building of
cumulus clouds east of the Cascades. We did have a mention of
thunderstorms in the forecast previously, although model data does
not support that this afternoon. The latest runs of the HRRR
don`t show anything and the latest run of the HREF does show some
radar reflectivity on the time lagged ensembles, although those
runs are based on older data sets. In any case, the threat of
lightning is around 5 percent east of the Cascades this afternoon.
Heading into the evening hours, the upper level low will swing
into north west Oregon with deeper onshore flow. The coast will
see yet another night in the low stratus and fog. It`s not as
clear how widespread fog will be, although we would expect some
patchy fog at the very least. By Monday, we`ll see temperatures
trend a few degrees cooler compared to this afternoon.
Interestingly enough, this will result in highs right around
normal for this time of year.
This upper level trough ends up cut off from the upper level flow
over Washington around the Tuesday to Wednesday time frame. In
addition, a short wave does move into northern California around
Tuesday morning. Anytime a shortwave does move in, one would think
thunderstorms. However, the airmass is exceptionally dry ahead of
this shortwave on Tuesday. We should just see some spotty cloud
cover at best.
From Thursday into Friday, the flow pattern looks more muddled
with high pressure struggling to build into southern Oregon.
However, the NBM suggests high temperatures will push back into
the upper 90`s in Medford and above station`s normal highs for
this time of year. In fact, we`re forecasting a high of 94 in MHS
On Friday which is one degree short of the record set in 2017.
Another topic worth discussing for the weather nerds out there is
next weekend. Some of the deterministic models suggest an upper
level low quickly moving through the Pacific Northwest. Both the
ECMWF and GFS do show a cold front driving down coast and perhaps
pushing inland a bit. Most ensemble members likely show something
similar with daytime high temperatures trending notable lower on
Saturday. This doesn`t impact the public side of things, although
it may have some fire weather impacts.
Lastly, ensembles show the four corners high building back in
around the day 7 to 9 time frame. Temperatures will trend higher
and the NBM does give some low probabilities for an impactful heat
wave. Currently a high of 108 is in the 75th percentile of
solutions for Medford. However, 95 degrees falls within in the
25th percentile of solutions. Obviously there is a fair amount of
spread in the day 7 to 9 time frame. One could conclude there is a
low potential of moderate to high heat risk towards the start of
September. Thanks for reading this reading this far in this rather
boring weather pattern.
-Smith
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...None.
&&
$$
Area Forecast Discussion
National Weather Service Mobile AL
709 PM CDT Sun Aug 21 2022
.AVIATION...
00Z issuance...Generally VFR conditions expected at all TAF sites
through the critical TAF period. Numerous showers and storms
continue to move across our region through the evening hours.
Expecting coverage to become more scattered to isolated in nature
later tonight. Ceilings may become locally reduced to MVFR
thresholds with visibility briefly dropping to MVFR/IFR categories
or lower in and near the heavier showers and thunderstorms.
Additionally, MVFR to IFR ceilings may develop late tonight into
early Monday morning, especially across interior portions of
southeast MS and southwest/south central AL (currently not
expecting impacts at any of the TAF sites). Going into Monday,
additional numerous showers and storms are expected to develop
again during the day on Monday with similar concerns of localized
ceiling/visibility reductions near showers/storms that develop.
Winds will generally be light and variable through tonight
(outside of stronger gusts within any storms). Winds then become
generally northeasterly around 5kts Monday morning with variable
stronger gusts in and around any storm development. JEH/88
&&
.PREV DISCUSSION... /issued 417 PM CDT Sun Aug 21 2022/
NEAR TERM UPDATE /Now Through Monday/...Early afternoon vapor imagery/500
mb height plots continue to show a shortwave trough digging across
the Great Lakes/Upper Midwest/Ohio Valley region, while deep layer
ridging continues to extend across the western Atlantic and into the
Gulf of Mexico. A deeply moist airmass remains firmly entrenched
across the north central Gulf Coast region early this afternoon,
with precipitable water values remaining high between 2.1 and 2.2
inches. PWAT values may continue to trend a little higher up to
between 2.2 and 2.4 inches across our forecast area through the
course of the afternoon and into early this evening. Shortwave
impulses translating eastward across MS/AL will continue to support
enhanced convective coverage within the deeply moist and rather
unstable environment this afternoon. We will continue to monitor
radar trends for heavy rainfall and localized flooding potential as
clusters of storms and/or storm mergers will have the potential to
produce rainfall amounts in excess of 1-2" within a short
period of time. The HRRR and ARW models have also shown some
agreement with the development of clusters of showers and
thunderstorms capable of producing heavy rainfall across our
southeast MS and adjacent southwest AL counties later this
afternoon into early this evening, so this will be an area
to watch for localized flooding concerns this afternoon and evening.
We cannot entirely rule out a couple of stronger storms capable of
producing frequent lightning strikes and brief gusty winds, but the
wet microburst wind threat currently appears limited this afternoon.
Scattered to numerous showers and thunderstorms are expected to
linger into the early to mid evening hours before gradually
diminishing by around or shortly after around 10-11 PM. Another mid
level impulse could aid in the initiation of additional scattered
showers and perhaps a thunderstorm over portions of the area,
particularly our interior northern counties overnight into the early
morning hours Monday. Additional shortwave impulses embedded within
the westerly flow pattern aloft will continue to translate across
our forecast area through the day Monday. The atmosphere will remain
extremely moist with precipitable water values continuing to average
toward the upper end of the spectrum between 2.25 and 2.5 inches per
the latest forecast guidance.
Numerous to widespread showers and thunderstorms will develop over
the forecast area, with the greatest coverage in the late morning
and afternoon hours. Heavy rainfall and localized flooding will
remain the primary concerns given the depth of moisture and the
associated potential for rainfall amounts to exceed 2" in a short
period of time. Instability will not be overly impressive given the
abundant cloud cover, but there could be pockets of MLCAPE in excess
of 2000 J/KG which could lend to a localized strong storm or two
capable of producing gusty winds. Low temperatures tonight are
forecast to range from around 70 degrees to the lower 70s over
inland locations and in the mid to upper 70s along the immediate
coast and beaches. Highs Monday currently only appear to range in
the lower to mid 80s over interior southeast MS and southwest and
south central AL and in the upper 80s over southern portions of the
forecast area. /21
SHORT TERM /Monday night Through Wednesday night/...Upper level
troughing will largely persist over the Southeastern US through
the period as a few shortwaves progress (and at times deepen)
within the overall flow. At the surface, a weak boundary will
remain draped with a west to east orientation across central
portions of Mississippi, Alabama, and Georgia. Guidance is still hinting
at the potential for a surface low to develop along the weak
boundary and move over the Lower Mississippi Valley late Monday
and into Tuesday. Although, there are still discrepancies among
the guidance with the strength of this feature it will help
weaken the surface ridge across the local area. Moisture will be
abundant across the region regardless of the low pressure
development with precipitable water values around 2.1 to 2.4
inches through Wednesday night. This moisture combined with the
upper level support of the shortwave series will keep the elevated
rain chances into the middle of next week with coverage generally
peaking during the afternoon and early evening hours. Decent
instability will be in place each day with MLCAPE up to around
1500 to 2000 J/Kg. Considering the appreciable water loading into
storms, can`t rule out a few wet microbursts each afternoon
resulting in strong to locally damaging wind gusts and frequent
lightning. However, the main concern will continue to be heavy
rainfall especially in areas where storms repeatedly move over the
same areas due to generally weak shear aloft. These training
storms could lead to localized flooding concerns given the wet
antecedent conditions. Temperatures will remain on the cooler side
compared to normal for this time of year given the increased
cloud cover and rain chances. Highs on Tuesday and Wednesday
should generally top out in the upper 70s and lower 80s inland
with middle 80s along the coast. Overnight lows drop into the
lower to middle 70s with the warmest temperatures occurring
near the coast. Some far interior areas could even see some upper
60s for lows Tuesday and Wednesday nights. /14
EXTENDED TERM /Thursday Through Sunday/...The upper level trough
over the Southeast will linger through the early part of the
extended with plenty of moisture in place. The numerous to
widespread showers and storms will likely continue into Thursday
given the similar pattern. Heavy rainfall and localized flooding
will likely persist into Thursday. As we head into the weekend,
the upper trough will begin to weaken as the western Atlantic
upper ridge tries to nudge into eastern portions of the region.
There are still some discrepancies among the ensemble and
operational guidance with the timing of the upper ridge
influences, but the general consensus is that we could see some
slightly drier air filter into interior portions of the area on
Friday and into Saturday as the weak boundary mentioned in the
short term pushes into the area. Showers and storms will still be
possible each day, but coverage may be a little lower than what
we`ve seen lately as we head into the weekend. Temperatures should
begin to warm through the period to more seasonal norms as the
upper ridge begins to move into the region. /14
MARINE...No notable marine impacts for the next several days given
generally light winds and low seas. Locally higher winds/seas will
remain possible near showers and thunderstorms. /21
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...None.
FL...None.
MS...None.
GM...None.
&&
$$
This product is also available on the web at:
www.weather.gov/mob
Area Forecast Discussion
National Weather Service Nashville TN
802 PM CDT Sun Aug 21 2022
...New UPDATE...
.UPDATE...
Issued at 757 PM CDT Sun Aug 21 2022
A broken line of storms is situated along the KY/TN border as part
of a weak cold front that is inching its way toward Middle
Tennessee. The HRRR shows this line gradually pushing southward
and then weakening after midnight as the atmosphere becomes more
stable. The evening sounding from OHX does show good instability
for now (CAPE of 1,396 J/kg, LI of -5), but also remarkably dry
above ~700 mb. Will keep low chance POP`s in the grids during the
overnight period as we may not ever go completely echo-free with
the cold front remaining in the vicinity.
&&
.SHORT TERM...
(This afternoon through Tuesday Night)
Issued at 224 PM CDT Sun Aug 21 2022
Frontal boundary now approaching the Ohio river. Activity has been
having a tough time getting going and it is appearing more and more
likely that the Hrrr solution may have the best handle on convection
going on into this evening. However, latest gfs and nam solutions
suggest a strong increase in lift across the area as we move into
the late afternoon hours. So, as we get toward posting time I will
make some adjustments potentially downward a touch from the 70 pops
I have for the late afternoon timeframe. At any rate, a marginal
risk is still in play into early this evening. Instability and wind
energy will drop off notably by 03Z. Prior to that time, a few
storms could contain some stronger winds. Patchy fog development
appears likely late tonight.
Moving on, the frontal boundary is expected to push into the area
tonight and attempt to move through by Monday afternoon. Low pops
will be included across our south during the day. The drier air for
the most part will win out Monday night and Tuesday. Having said
that, patchy fog does look likely as moisture remains in the lowest
levels for late Monday night. Numerics all seem to peg the south and
east with rather low vsbys.
For the near term temps, numbers are looking seasonal with lows upper
60s and highs upper 80s.
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 224 PM CDT Sun Aug 21 2022
For the extended forecast, its important to note that the heavy rain
fcst which was located over ne TX and eastward through northern LA
is now shifting eastward. Not much northward movement but the heavy
rain potential axis is a little closer to middle TN now. At any
rate, it still appears that the focus of the stationary boundary
will be to our south.
Differences in the GFS and Euro solutions are rather apparent. The
Euro hangs on to the upper troughing with stronger forcing along the
aforementioned boundary to our south. The GFS is much stronger with
the mid/upper level ridging over the nations interior. This is
acting to drive drier air southward, keeping the extended period
drier. Will opt to lean toward a blend with low pop inclusion
mainly across the south with diurnal emphasis.
For the extended temps, continuing the theme of blending the GFS and
the euro, it looks like temps will run a few degrees above normal.
Even with the Euro, the weak upper troughing still carries some
relatively higher height values. Highs near 90/lower 90s will
return over the extended period.
&&
.AVIATION...
(00Z TAFS)
Issued at 633 PM CDT Sun Aug 21 2022
SHRA/TSRA will affect airports at varying times this evening as a
cold front sinks southward across the area. Overnight, fog is
expected at CSV with LIFR/VLIFR conditions, and cannot rule out
vis reductions at the other airports as well but uncertainty is
high. Light southwest winds this evening will veer to northwest
with fropa.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 69 87 67 89 / 40 10 10 10
Clarksville 67 87 64 87 / 30 10 10 10
Crossville 66 79 64 81 / 60 30 10 10
Columbia 68 87 66 89 / 50 20 10 10
Cookeville 68 81 66 83 / 60 30 10 10
Jamestown 66 78 65 81 / 60 30 10 10
Lawrenceburg 68 86 67 87 / 50 30 10 20
Murfreesboro 68 87 66 89 / 50 20 10 10
Waverly 65 87 64 87 / 30 10 10 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...21
LONG TERM....21
AVIATION.....Shamburger
Area Forecast Discussion
National Weather Service Tucson AZ
349 PM MST Sun Aug 21 2022
.SYNOPSIS...Daily showers and thunderstorms will continue this
coming week into next weekend although the heavy rainfall threat
will be much less than this past weekend. Temperatures will be
well below normal today then follow a warming trend during the
work week.
&&
.DISCUSSION...500 mb analysis this morning showed weak trofiness
over far SE AZ, likely the remants of the tropical wave that
impacted the area Fri/Sat, and a mid-level high centered off the
srn CA cst. This put the western half of the forecast area under
N/NE flow aloft which will have transitioned east across the area
today as the above mentioned weak trof moved east into srn NM.
21/12z Tucson showed steering flow out of the N/NE, upper level
winds out of the W/SW and PW value still very moist at 1.81" but
down from the near record levels of 24 hours.
Mid-afternoon radar showed isolated storms south and east of
Tucson. Latest HRRR propagates widely scattered storms S/SW across
the lower elevations thru midnight. Main threats will be strong
gusty winds and localized flash flooding.
Daily chances of showers and thunderstorms will continue this week
into next weekend. Primary threats each day will be strong gusty
winds, lighting and localized flash flooding.
Temperatures will be warmer Monday then run a few degrees below
normal for the remainder of the week into next weekend.
&&
.AVIATION...Valid through 23/00Z.
Scattered cloud decks at 6k-9k ft AGL thru 22/04Z with WDLY SCT
SHRA/TSRA. The stronger SHRA/TSRA could reduce visibilities in
heavy downpours, briefly lower CIGS to 3k-6k ft AGL and produce
gusts to 40+ kts. Expect skies to slowly clear aft 22/04Z. Storms
developing again Monday afternoon. Otherwise, winds will follow
diurnal trends at speeds of 10 kts or less. Aviation discussion
not updated for TAF amendments.
&&
.FIRE WEATHER...Daily chances of showers and thunderstorms through
next weekend. Primary threats will be strong winds, lightning,
and flash flooding. Outside of thunderstorm activity, wind trends
will remain light and follow typical diurnal trends.
&&
.HYDROLOGY...Rainfall over the Gila Basin in New Mexico over the
past 36-48 hours has led to a significant increase in the flow in
the Gila River. River Flood warnings have been posted in New
Mexico for the Gila River with the higher flows moving downstream
through Duncan over the next 12 hours. The latest forecast from
the Colorado Basin River Forecast Center (CBRFC) has water levels
remaining below flood stage at Duncan with the water level
creasting between 10 pm and midnight then gradually falling
through Monday morning.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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