Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/28/22
AREA FORECAST DISCUSSION
National Weather Service Albany NY
1002 PM EDT Sat Aug 27 2022
.SYNOPSIS...
Generally dry weather is expected through Sunday, with
temperatures near or a bit above normal. Hot and increasingly humid
weather returns for Monday and Tuesday, with the next chance for
showers and thunderstorms late Tuesday or Tuesday night as a
cold front approaches from the west.
&&
.NEAR TERM /UNTIL 6 AM SUNDAY MORNING/...
As of 1002 PM EDT....Satellite imagery and surface observations
shows that all diurnal cumulus has dissipated and skies are
completely clear over eastern New York and western New England.
High pressure is located over northern New England and it will
slowly be drifting southeast for the overnight hours towards the
Gulf of Maine. The low level flow around this high pressure area
will be out of the east-southeast, which may allow for some
moist, marine air to move in off the western Atlantic. This
could allow for some low stratus to move into southern and
eastern areas for the late night hours or towards daybreak. This
will mostly impact areas south and east of the Capital Region.
The latest 3km HRRR and NAM both suggest that any showers that
form will stay south of the area. For areas that remain the
most clear (mainly north/west of the Capital Region), some
patchy radiational fog may form in the typical spots, thanks to
the clear skies and light/calm winds.
Min temps will dip into the mid/upper 40s across portions of
the southern Adirondacks, and lower/mid 50s across the upper
Hudson Valley into the Saratoga region, with upper 50s to
lower/mid 60s farther south and east.
&&
.SHORT TERM /6 AM SUNDAY MORNING THROUGH MONDAY NIGHT/...
Areas of low clouds may linger through at least mid morning
within portions of the Hudson River Valley from the Albany-
Saratoga region southward, and east into the Berkshires.
Litchfield Hills, mid Hudson Valley and southeast Catskills,
with clearing then expected for the afternoon. It will be warm
with moderate humidity levels, with max temps reaching the
mid/upper 80s for many valley areas, and upper 70s to lower 80s
for higher terrain. Dewpoints should drop off into the upper
50s/lower 60s in the afternoon.
Clouds may reform again Sunday night, again favoring areas from
Albany south and east. Otherwise, milder than tonight, with lows
generally in the 60s, except for some mid/upper 50s across some
northern areas.
Some morning clouds should give way to breaks of afternoon
sunshine Monday, and with warmer air aloft, max temps should
reach at least 85-90 within many valley areas, and 80-85 across
higher terrain. Dewpoints will edge slightly higher, into the
lower/mid 60s in the afternoon, yielding max heat indices mainly
in the lower 90s. Should slightly higher humidity levels develop
than currently indicated, some areas within the Hudson River
Valley could approach heat advisory criteria. There could also
be isolated late day showers/thunderstorms across portions of
the Mohawk Valley and southern Adirondacks.
Warm and muggy for Monday night, with the possibility for
additional isolated/scattered showers and thunderstorms across
the Mohawk Valley and southern Adirondacks. Lows mainly in the
60s.
&&
.LONG TERM /TUESDAY THROUGH SATURDAY/...
A longwave upper level troughing pattern looks to dominate the long
term forecast period. Two associated cold frontal passages will help
cool things off late next week after potentially dangerous heat
Tuesday. The combination of high humidity and the incoming frontal
system could cause widespread convection Tuesday, but injested dry
air Wednesday will make for a dry rest of the week.
The long term forecast period begins with a longwave, upper
level trough situated just to our west over the Great Lakes with
the associated closed low pressure outstretched overhead across
the border of Quebec and Ontario. Model guidance agrees that
this system will amplify as it progresses eastward into our
region Tuesday, though there is slight uncertainty about the
exact timing behind its entrance. The system approaches with an
associated cold front whose passage looks to occur late Tuesday
afternoon into Tuesday night. This front, in interacting with
Tuesday`s unseasonably warm temperatures and elevated humidity,
has the potential of causing widespread convection throughout
the region.
Wednesday will see the continued amplification of the same system,
though as a result of the previous day`s cold front, will begin the
cooling trend of the remainder of the week. A secondary cold front
will pass through Wednesday afternoon into Wednesday night as a
result of an embedded shortwave within the upper level trough. Lower
humidity levels and dry air associated within this new airmass
significantly decrease the likelihood of convection. As the trough
begins to weaken and move out of our region to the northeast during
the day Thursday, cooler temperatures stay behind, making for a
comfortable rest of the week.
Tuesday will definitely be the hottest day of the period with
temperatures in the mid to upper 80s. Dewpoints in the mid 60s to
low 70s could make this a potentially dangerously hot day with
apparent temperatures in the 90s. Wednesday should be cooler with
temperatures in the mid to low 80s and decreased humidity levels.
Thursday and Friday also look to be in the low 80s at lower
elevations with higher elevations looking to be in the mid to upper
70s.
&&
.AVIATION /02Z SUNDAY THROUGH THURSDAY/...
Flying conditions are currently VFR across the area with nearly
clear skies. Any diurnal cumulus will continue to dissipate and
light northeast winds around 5 to 8 kts will becoming very
light or calm for the overnight hours.
With high pressure east of the area, the flow around this high
will allow for some moisture off the western Atlantic to work
its way towards the area. Some low-stratus clouds may start to
spread into the area for the late night hours, mainly for
KPSF/KPOU, where some MVFR cigs are possible after 07z or 08z.
KALB may see some late night hours clouds too, but they may
wind up staying in the VFR range. Meanwhile, clear skies for
much of the night at KGFL could allow for some radiational fog
to form after midnight, with IFR conditions possible there
thanks to the low visibility. If stratus clouds are delayed or
further south, some patchy fog could form at KPSF as well.
The low stratus and fog may linger for a short period after
daybreak, but should dissipate for all sites by mid-morning,
allowing for VFR conditions to return. Some diurnal cu may
develop again on Sunday by afternoon, with sct-bkn cigs around
4-6 kft, but no precip is expected. South to southeast winds
will increase to 5 to 10 kts during the day on Sunday.
Outlook...
Sunday Night: No Operational Impact. NO SIG WX.
Monday: No Operational Impact. NO SIG WX.
Monday Night: No Operational Impact. NO SIG WX.
Tuesday: High Operational Impact. Breezy. Likely SHRA...TSRA.
Tuesday Night: Moderate Operational Impact. Likely SHRA...TSRA.
Wednesday: Low Operational Impact. Slight Chance of SHRA.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
MA...None.
VT...None.
&&
$$
SYNOPSIS...KL/Thompson
NEAR TERM...Frugis/KL
SHORT TERM...KL
LONG TERM...Frugis/Gant
AVIATION...Frugis
Area Forecast Discussion
National Weather Service La Crosse WI
656 PM CDT Sat Aug 27 2022
.DISCUSSION...(This evening through Saturday)
Issued at 320 PM CDT Sat Aug 27 2022
Key Messages:
- Severe storm potential this evening and heavy rain potential tonight
- Another round of storms Sunday evening/night
- Cooler temperatures and dry weather next week
Now: Radar continues to indicate a back edge to the rainfall over
central WI which has been incredibly slower than forecast. Rainfall
amounts of 2-3" fell along I-94 from Mauston to sw of Tomah. This
all in the warm advection and frontal zone in low-levels oriented
northwest to southeast now near I-94 at around 850 mb. Persistent
instability feeding into the zone with 30 kts of isentropic lift in
swrly flow did the trick. Further southwest, clearing has occurred
with northeast IA and southeast MN in the 80s and a noticeable
billow cloud boundary from Dodge Center to about Dubuque...
indicating strong inversion conditions to its northeast in the rain
cooled air. SPC mesoa indicates about 2k J/Kg of MLCAPE west of this
boundary in S-SE flow surface flow. Wind shear is not impressive but
I would classify it as entry level for organized storms. 0-1km bulk
shear is about 20 kts and 0-3km shear around 25-30 kts with no
increase above (no deep shear). Most of IA is clear and
destabilizing but capping is still in place. GOES water vapor
imagery shows a well-formed shortwave trough approaching Omaha
moving into the instability and directly toward the area.
As the later afternoon and early evening approach, some storms are
expected where convergence occurs AND the cap can be overcome.
Certainly the warm frontal zone / billow cloud boundary could be one
area for storm development but general confluence of the flow
appears to be present near or west of I-35. The latest HRRR and
CAMS indicate this scenario and storms moving into the SPC slight
risk area from the west. Wind shear may increase as the shortwave
trough approaches, but still isnt very strong. So, it appears
pulse hail storms /up to ping pong balls with early storms/ and
bowing segments are possible for wind damage if they orient NW-SE
perpendicular to the 0-3km shear vector.
The impressive shortwave trough will move overhead tonight and
provide a re-invigoration of the forcing. The low-level jet
intensifies per RAP forecasts and with the large scale lift,
conditions continue to favor thunderstorm development. Overnight
the precipitable water values approach 1.50-1.75" after 03Z per
27.12Z HREF and warm cloud depths increase toward 4 km. Both of
these are favorable, although not highly anomalous. So, in
combination with the evening pre-wave storms, additional waves of
storms will occur until the wave axis passes acting to clean storms
from southwest to northeast later tonight. The 27.18Z HREF mean has
totals of 1.5-3" from KRST-KMCW swwrd, but a better idea of reports
in the localized maxes comes from the local probability matched mean
/LPMM/ which is indicating 5" totals possible. HEFS river stage
probabilities available on our River and Lakes web page area
indicates very low probabilities of flooding on rivers from the GEFS
inputs. Soils can take totals of 3-4" /3h,6h FF guidance 3.5"/, but
steep terrain areas and cities such as Rochester (on the
rain axis) would have some flooding issues. However, with
southwesterly flow, prolonged storm rounds through ~09-10Z in
sern MN and nern IA, was just above a 50% confidence level that
flash flooding could occur overnight. This agrees well with the WPC
excessive rainfall slight risk area which matches the SPC slight
risk area very closely...NW-W-SW of La Crosse WI.
Much less rainfall is expected in WI where it rained today 2-3.5",
but this area must be watched for expansion of the Flash Flood
Watch.
Focus turns to Sunday into Sunday night...Shortwave energy from
tonight into Sunday morning slowly tracks northeast of the forecast
area during the day Sunday. Latest 27.12z deterministic models show
moisture feed continuing through the daytime...especially in the
morning hours. Showers and storms could linger for much of the
morning hours and diminish in the early afternoon as shortwave
energy moves east of the area. Next concern is vigorous upper level
trough...and associated surface front...moving across the Northern
Plain States into the forecast area Sunday evening/night. Along and
just ahead of the surface front...line of convection is expected to
develop over central Minnesota. The latest 27.12z deterministic and
hi-resolution models suggest the timing of this convection and upper
level trough/surface front to move into the western portion of the
forecast area after 00z to near 03z Monday. With this late of
timing...instability out ahead of trough/surface front begins to
diminish across the forecast area. However...0-3km shear from the
27.12z NAM shows 30 to 35 knots from 00z to 06z Monday across the
northern portions of the forecast area. Initially when line moves
into the far northwestern portion of the forecast area...the storms
should have the potential for severe...though instability is
weakening...convection should weaken as well and the severe
potential should rapidly diminish as line of convection tracks over
the northern portions of the forecast area. Potential of severe with
any storms will be in the 00z to 03z Monday timeframe and after 03z
Monday...expect the convection to weaken and be below severe limits.
The main threats for severe will be damaging winds and hail.
Main forecast concerns Tuesday through Saturday are mainly
temperatures through the period. Upper level trough moves into the
northeast United States and shortwave ridge builds into the central
United States through the period. Northerly flow aloft on the
backside of upper level trough will advect a cooler airmass into the
Upper Great Lakes region and allow for cooler than normal
temperatures early in the period...mainly Wednesday into Thursday.
As shortwave ridge builds into the central United States...
temperatures gradually warm Friday into Saturday to near normal.
With shortwave ridge dominating the forecast area through much of
the period. Subsidence underneath shortwave ridge will suppress any
shower or storm development and much of the forecast area will
remain dry Tuesday night into Saturday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 655 PM CDT Sat Aug 27 2022
Showers and a few thunderstorms are in the local area. With
continued moisture transport and an increasing low level jet,
should continue to see on and off showers and thunderstorms during
the evening and overnight hours as a couple of shortwave troughs
rotate through the area. Tough to time convection due to the pop
up and weakening nature with a few rounds of embedded more
organized storm activity. Mainly VFR conditions, however with the
heavier rains/storms patchy MVFR/IFR conditions are possible along
with gusty winds. We should see the rain area shift east of the
KRST area after 14 to 16Z and 18 to 20Z at KLSE. Southeast winds 6
to 12kts with periods of gusts 15 to 25kt increase Sunday after
from the south 10 to 20kts with gusts 15 to 28kts.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...NONE.
MN...Flood Watch from 10 PM CDT this evening through Sunday morning
for MNZ079-086>088-094-095.
IA...Flood Watch from 10 PM CDT this evening through Sunday morning
for IAZ008-009-018-019.
&&
$$
DISCUSSION...Baumgardt/DTJ
AVIATION...Zapotocny
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1036 PM CDT Sat Aug 27 2022
.UPDATE...
Issued at 1035 PM CDT Sat Aug 27 2022
Thunderstorms are starting to push into western North Dakota ahead
of a cold front. Overall the threat for severe weather remains low
with this initial push of storms. There is some increased CAPE in
the southwest, and all areas still see high amounts of DCAPE. In
additions 0 to 3 KM shear is increasing, although 0 to 6 KM shear
still remains low. This combined with inverted-v soundings
supports a wind threat with any thunderstorm tonight. Perhaps a
gust up to 60 MPH is possible, although generally 40 to 50 mph
winds are expected. The lack of overall shear and higher amounts
of CAPE should limit the hail threat. As this front progresses
eastward so will the showers and thunderstorms tonight. There is a
possibility of some isolated stronger storms Sunday morning,
mainly from about Bismarck to Jamestown and nearby areas. Right
now this is a low confidence situation, although MUCAPE over 1000
J/KG along with increasing shear from the low level jet may
promote a stronger storm. Winds again will be the main threat,
although steep mid level lapse rates could also see for some near
severe hail. This is all conditional at this time and something
worth monitoring.
UPDATE Issued at 650 PM CDT Sat Aug 27 2022
We continue to be under the influence of warm conditions ahead of
a cold front this evening. Other than an isolated thunderstorm in
the northeast, conditions look to remain mainly dry until around
sunset. Near to shortly after sunset a cold front approaching the
state still looks to bring showers and thunderstorms to the west.
The threat for severe weather is still minimal as instability
after sunset is lacking. There is modest shear and high DCAPE
values. So any storms that can develop may pose a damaging wind
threat with perhaps some small hail. The window for these stronger
storms is short and generally before midnight. The front then
looks to push eastward through the night and day Sunday. This
could bring showers and isolated thunderstorms as it does so.
Upper low moving across the north later in the day Sunday could
then bring another round of showers, mainly in the north. Overall
made some minor PoP adjustments to account for the latest hi res
model trends. Otherwise, the forecast remains on track.
&&
.SHORT TERM...(This Evening through Sunday)
Issued at 217 PM CDT Sat Aug 27 2022
Early afternoon satellite imagery shows a weak shortwave moving
east northeast into the eastern part of the state with a low
amplitude ridge axis to our west. At the surface, a warm front was
located over central North Dakota and will continue to drift east
through the afternoon.
This will mean plenty of sunshine and warm temperatures through
the rest of the day. Highs will range from the low to mid 80s east
to the upper 80s/lower 90s central and west.
The ridge axis approaches the Montana border late this afternoon
and into this evening, followed by height falls associated with
the next shortwave trough. Showers and thunderstorms are likely to
be ongoing across eastern Montana as the trough and associated
cold front approaches. This activity will move into west central
and southwestern North Dakota in the 01z to 04z time frame. Per 15z
RAP soundings, the environment here will be characterized by
MUCAPE values in the 500 to 1500 J/kg range with around 25 to 35
knots of deep layer shear. Thus a strong to marginally severe
storm will be possible. Winds up to 60 mph and large hail to the
size of quarters will be the primary threats, along with frequent
lightning. The strong/severe threat shouldn`t last long as
instability and shear weakens with eastern extent and the diurnal
trends become less favorable. Elsewhere, isolated to scattered
showers and thunderstorms will be possible overnight, but these
storms should not be as strong.
Most of the area will remain under the influence of the shortwave
through the day on Sunday, but the best forcing for showers and a
few thunderstorms will be across the north and east. Tomorrow will
also be cooler and breezy behind the front with highs mainly in
the 70s (a few lower 80s possible east). Winds become westerly
Sunday afternoon with the strongest winds across the west, with
sustained values up to 23 mph and gusts to 35 mph. Winds across
the central and east will still be breezy but not quite as strong.
.LONG TERM...(Sunday Night through Saturday)
Issued at 217 PM CDT Sat Aug 27 2022
Chances of showers will linger north central and northeast Sunday
evening, with only a small chance for a rumble of thunder or two.
Clouds will be on the decrease through the rest of the night,
leading to a mostly clear sky and lows ranging from the upper
40s/lower 50s west to the upper 50s east.
The long term then becomes fairly quiet with an expansive ridge
setting up over the western US. The ridge axis will slowly move
towards the Northern Plains through the week, promoting a gradual
warmup. Monday will see highs in the mid 70s to lower 80s, with
some 90s returning to the forecast across the west by Thursday and
Friday. Some deterministic global models and ensemble members
suggest a weak wave or two coming down the ridge towards the end
of the long term, but confidence is low regarding specifics given
considerable ensemble spread. For now, will stick with NBM
probabilities which keeps the area dry after showers exit Sunday
evening.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday Evening)
Issued at 650 PM CDT Sat Aug 27 2022
VFR conditions are generally expected through the forecast period,
except during periods of showers and thunderstorms. Later this
evening through tonight, a cold front looks to bring shower and
thunderstorm chances from west to east perhaps bringing some MVFR
conditions at times. An isolated stronger storm is possible
tonight, mainly in the southwest. Initial round of showers and
thunderstorms looks to push eastward through Sunday morning into
early Sunday afternoon. Another round of showers and thunderstorms
are then possible across the north Sunday afternoon. This shower
activity may also bring some MVFR conditions at times, with some
general lowering of ceilings across the north later in the day
Sunday. Look for breezy westerly winds to also develop behind this
mentioned cold front on Sunday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Anglin
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...Anglin
Area Forecast Discussion
National Weather Service Des Moines IA
625 PM CDT Sat Aug 27 2022
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Saturday/
Issued at 223 PM CDT Sat Aug 27 2022
Key Messages:
-- Very localized, urban flash flood concerns overnight
-- Severe risk of hail, wind gusts through early evening
-- Few strong storms possible on Sunday
-- Turning drier with low humidity and seasonable much of next week
Details: First round of showers and thunderstorms was mostly focused
over Minnesota with a few storms over far northern Iowa this
morning. This activity was largely forced by low level thermal lift
that has since exited the region. There has been a lull in forcing
across central Iowa since then and attention is to the west on an
approaching lead shortwave trough. As of early afternoon, this is
located over eastern Nebraska and Kansas with associated convective
elements ahead of this wave. As this theta-e and kinematic forcing
spreads into Iowa late this afternoon and early this evening,
scattered thunderstorms will develop. Forecast soundings show
appreciable effective shear arriving with the wave with greater than
1500 J/kg of surface CAPE. Will monitor trends in the latter through
this afternoon as models have been running a little higher than SPC
mesoanalysis. This could be the result of more cloud cover holding
down temperatures a bit. Sounding shape does show a good region of
instability within the hail growth zone such that large hail will be
a threat to start. Damaging wind gusts may also be a concern with
downdraft CAPE values over 1000 J/kg; however, as the mid-levels
saturate, the lapse rates therein will weaken ending the hail risk.
Some gusty wind potential exists with dry air in the low levels into
at least early this evening, but even that should end by mid-evening
as the low levels saturate. With the column becoming moisture laden,
precipitable water values increasing to around 1.75 inches, deep
warm cloud depths, and 850-300mb flow favoring training storms,
concern will transition to locally heavy rainfall for the overnight.
Interestingly, the 00z ECMWF extreme forecast index has a weak
signal -- that being a 50 to 60% of its ensemble members showing
higher end rain totals compared to the model climatology. While this
is not typically considered a significant signal, the fact that over
half of its ensemble members are showing this for a convective event
seems at least noteworthy. The upper end deterministic models such
as the NAM, FV3, WRF-ARW, RAP, and HRRR show 3 to 4 inches by Sunday
morning and in the morning/recent runs have focused this over parts
of north central into northeastern Iowa. This area of higher QPF
lines up fairly well with the global ensemble placement of the
highest QPF amounts as well. Looking at amounts from the 00z/12z
HREF localized probability matched mean, there is signal for 5 to 7
inches in a few areas. While soils have been dry, this is
reminiscent of a few weeks ago where a few rain gauges in rural
areas of Worth and Winnebago Counties recorded 8 inches overnight.
In that event, no flash flooding reports were received. Agricultural
land will likely be able to handle this rainfall due to the dry
antecedent conditions and flash flood guidance of 2-3". However, the
greatest concern for flash flooding overnight remains for any urban
area, particularly Mason City. If the higher end QPF advertised in
the HREF occurs, which is around double the flash flood guidance,
flash flooding could occur either from a quick few inches or short
succession between repeat rounds that would not allow stormwater
drainage to recover capacity before the next round. Therefore, have
decided to issue a flood watch for flash flooding tonight over a
part of north central Iowa with the messaging heavily hitting
that the greatest flash flood threat will be in urban areas.
After the overnight convection dissipates and departs Sunday
morning, there should be a break as the lead shortwave trough leaves
and the main shortwave trough moves eastward along the US/Canadian
border. The stronger forcing will be north of Iowa and an elevated
mixed layer will keep the atmosphere capped during the daytime. As a
cold front associated with the trough swings into central Iowa early
Sunday evening, scattered storms could develop. Synoptic models
except the CMC show some QPF moving through during this time frame.
However, CAMs are split with the more storm prone FV3 and NamNest
showing a line of storms while the HRRR and the WRF-ARW, which the
latter tends to be more convective prone, are rather quiet. For now,
will hold onto PoPs, but uncertain on coverage. While SPC did expand
the marginal over Iowa on day 2/Sunday, we coordinated with SPC to
hold off on slight category given the uncertainty this far south
with better forcing farther north. If storms do form, they will be
elevated with the better shear closer to the boundary. Mid-level
lapse rates are steep and could yield a hail threat and theta-e
differences of 20 to 30K into the early evening could pose a risk of
strong wind gusts/downdrafts.
The front will continue to slog southeastward through Monday with
lingering showers and storms in the far southeast. The main trough
axis will push east of the region by Tuesday morning with a ridge
amplifying over the western US. This will place Iowa beneath
northwesterly flow aloft and with surface winds not having a
southerly component, this will keep dewpoints in the 50s from
Tuesday onward to the end of the period. Temperatures will be near
climatological normals (a few degrees either side of 80) for late
August and early September. Right now, favoring a dry forecast in
this timeframe. However, there is a sign in the deterministic and
ensemble guidance that a shortwave trough will rotate through the
top of the ridge middle into late in the week suppressing the ridge
axis and perhaps pushing it westward. Whether this brings any
rainfall to the state has a high degree of uncertainty at this time
and hence favor the dry conditions for now.
&&
.AVIATION.../For the 00Z TAFS through 00Z Sunday evening/
Issued at 623 PM CDT Sat Aug 27 2022
Widespread SHRA/TSRA activity will be the primary aviation concern
through this evening and overnight. MVFR to IFR conditions are
likely at times as heavier activity moves through. Expecting much
of the area to dry out by 12z Sunday morning, giving way to VFR
conditions through the remainder of the day. KMCW may see MVFR
stratus linger a bit later into the morning, but should raise by
15z.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Flood Watch from 10 PM CDT this evening through Sunday morning
for IAZ006-007-016-017-025>027.
&&
$$
DISCUSSION...Ansorge
AVIATION...Martin
Area Forecast Discussion
National Weather Service Goodland KS
454 PM MDT Sat Aug 27 2022
.SHORT TERM...(This evening through Monday night)
Issued at 142 PM MDT Sat Aug 27 2022
At the start of the short term period, the latest RAP analysis shows
the CWA being under the base of a weak trough with a west-
southwesterly flow aloft. Current satellite and surface observations
show some mostly sunny skies with some high clouds for a good
portion of the CWA with the far eastern counties seeing some cloud
development along some possible surface convergence. May see some
isolated thunderstorms pop-up with this with CAPE values around 1500
J/kg and effective shear around 30 kts in the area though they are
not expected to be severe. Forecast models show an upper air low
traveling east along the northern MT border during the evening and
overnight hours turning the upper air flow to northwesterly to
westerly across the CWA during the remainder of the day. At the
surface, dry conditions are expected for the CWA with light and
variable winds along the CO border care of a surface low pressure
with Norton and Graham counties seeing southerly winds gusting up to
around 30 mph during the afternoon and evening hours. Clear skies
are seen overnight with southerly to southwesterly winds around 5 to
10 mph. Daytime highs between the upper 80s and lower 90s are
expected with overnight lows in the middle 50s to middle 60s.
On Sunday, forecast guidance shows the upper air low continuing to
move east along the Canada/U.S. border with a ridge trailing it in
the Pacific Northwest. With the passage of the low well to the north
of the CWA, the CWA`s upper air flow stays westerly during the day
and turns northwesterly by the nighttime hours. Closer to the
surface, models show some WAA with 850mb temperatures around 30
degrees Celsius during by the late afternoon hours. With this,
daytime highs warm up and look to range between the lower 90s and
lower 100s. With these warm temperatures, minimum RH values look to
drop to as low as 12% during the day. While winds do not support
fire weather conditions, going to begin messaging possible elevated
fire weather with these dry conditions during the afternoon. Also,
eastern portions of the CWA may see a slight chance for showers and
thunderstorms during the late afternoon and evening ahead of an
approaching cold front. Minimal precipitation is expected if it
occurs and severe weather is not anticipated with any storms at this
time. Overnight lows on Sunday look to be between the middle 50s and
middle 60s.
For Monday, models show the CWA moving underneath the ridge as it
progresses farther eastward. At the surface, dry conditions look to
be on tap for the CWA with east-northeasterly winds around 10 to 15
kts. Fire weather is not expected with these winds as well as
minimum RH values in well above criteria. Monday`s daytime highs
look to range between the upper 80s and lower 90s with overnight
lows in the middle 50s to lower 60s range.
.LONG TERM...(Tuesday through Saturday)
Issued at 122 PM MDT Sat Aug 27 2022
The long term forecast is looking to be pretty mild and
persistent. In the upper-level, a ridge will extend into Alberta,
Canada from the Southern Rockies on Tuesday. The axis of the ridge
will rotate throughout the forecast period and by Saturday, the
ridge will extend over the Dakotas. The positioning of this ridge
will cause the jet stream to move farther east and away from the
CWA, and a northwesterly flow over the Tri-State area.
Wednesday is shaping up to be the warmest day in the forecast
period, with maximum temperatures in the upper 80s to mid 90s.
Thanks to some extra cloud cover, temperatures begin a slight
cooling trend through Friday, when maximum temperatures look to
top out in the mid to upper 80s. Saturday could be slightly warmer
as the LLJ, coming out of the south, strengthens overnight Friday
and will help move warmer air into the Tri-State area causing high
temperatures to be in the mid 80s to lower 90s Saturday afternoon.
There is the possibility that more moisture, and in turn clouds,
could move into the area with these southerly winds. If the cloud
cover notably increases, maximum temperatures could stay in the
upper 80s for more of the CWA on Saturday. Overnight temperatures
will be in the mid 50s to low 60s for the long-term forecast.
There is a chance for isolated showers in the afternoon and
evening hours on Tuesday through Thursday. The best location for
these showers will be in and around eastern Colorado and
southwestern Nebraska. Due to a lack of forcing, there is low
confidence that widespread storms will form. PoPs could increase
if a shortwave moves across the area, but current PoP values are
below 20 in the long-term.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 452 PM MDT Sat Aug 27 2022
For KGLD & KMCK... VFR conditions are expected through the period.
Winds will be roughly from the south at 10kts or less at the start
of the period. The winds will then transition to be more west
northwest through the early morning and daytime hours tomorrow
with speeds around 10 kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
SHORT TERM...076
LONG TERM...CA
AVIATION...KAK
Area Forecast Discussion
National Weather Service Medford OR
826 PM PDT Sat Aug 27 2022
.UPDATE...NO changes were necessary this evening, as the forecast
appears to be right on track.
It will be a mostly quiet night across southern Oregon and far
northern California, with mostly clear skies and seasonable
temperatures. The exception to this will be the Illinois and lower
Rogue valleys, as well as portions of the south coast, where
smoke from the Rum Creek fire will continue to reduce air quality
and create a generally hazy and/or smoke filled sky. Tomorrow, we
will see ridging return to the region, and a warming trend is
expected through at least the first half of the week. For more on
this and the rest of the forecast, see the previous discussion
below. -BPN
&&
.AVIATION...28/00Z TAFs...Conditions are expected to remain mainly
VFR across the area through Sunday afternoon except for areas of
smoke creating low visibilities over Josephine and Curry counties.
Gusty winds are expected at the coast Sunday afternoon. -CC
&&
.MARINE...Updated 800 PM PDT Saturday 27 August 2022...The thermal
trough will remain strong through Sunday, resulting in gale force
north winds and very steep seas from Gold Beach south, for waters
beyond 5 miles from shore. Gusty north winds and steep seas,
hazardous to small craft, will persist for all other areas through
Sunday. Winds will gradually lower Monday, although seas will remain
steep through late Monday afternoon. Seas and winds will be
relatively calm Tuesday through Thursday. -CC
&&
.PREV DISCUSSION... /Issued 305 PM PDT Sat Aug 27 2022/
DISCUSSION...Though our weather pattern over the next week will
be more complex than simple ridging, nonetheless conditions will
mostly be similar to those under a strong ridge: warmer and drier
than normal with a stable air mass. This includes a return to a
more summer-like pattern at the coast, with more limited coverage
and duration of stratus compared to the stratus surge from last
night...especially tonight with the effect of easterly winds.
A new warming trend will start Sunday with inland temperatures
mainly at 10 to 15 degrees above normal from Monday through the
Labor Day weekend. With a largely straight-forward forecast, the
focus was two-fold.
First, relying heavily on the HRRR model to forecast the shifting
coverage of smoke generated by the Rum Creek Fire in northern
Josephine County. North to northeast winds will particularly increase
smoke in the Illinois, lower Rogue, and Applegate valleys. For
now, the forecast reflects the capabilities of the HRRR with a
forecast covering the period into Monday morning. There is also
smoke from the Six Rivers Lightning Complex in Trinity County that
has spread across Siskiyou County into south central Oregon.
Second, the 12Z GFS has been surprisingly consistent over the
past few days, along with a consistently distinct minority (around
10% of GEFS ensemble members) in showing conditions that would
support a slight chance of showers, perhaps a few thunderstorms in
Lake County Tuesday afternoon/evening. The latest NBM model
probability of thunderstorms on Tuesday, did paint the highest
probability of thunderstorms in that area...nudging it up from
around a 5% to an 8% probability. Thus, the NBM was utilized and
we will continue to monitor over the next few days for justification
in raising or lowering that low probability. A lower probability,
near but non-zero, exists for the other parts of our area from
the Cascades eastward.
The possible convection on Tuesday would be generated by a shortwave
splitting off from last night`s trough passage. It is expected to
develop into a weak closed low along the central California coast,
and may move to the vicinity of Modoc and Lake counties by
Tuesday afternoon on its track northeastward.
The 12Z data still suggests another weaker cold frontal passage/marine
push on Thursday night into Friday morning, somewhat similar to
last night but shallower and drier. Ridging is likely to follow
Friday. Model agreement diminishes going into the holiday weekend,
though a majority of data supports dry, warmer than normal
conditions. Another frontal passage is possible around Saturday
night into Sunday morning. The bulk of solutions are in two camps,
either focused north of our area, or similar to Thursday night
with another breezy, very shallow marine push.
&&
.FIRE WEATHER...Updated 215 PM PDT Saturday 27 August 2022...
The region is observing its coolest and moistest day in a while.
Despite this, Modoc County will remain quite dry and gusty afternoon
winds along the Warner mountains could cause critical conditions to
be briefly observed. Also gusty east winds will persist tonight in
SW Oregon and western Siskiyou County, keeping RH recoveries low
along ridgelines in that area. Valleys in that area should observe
much fuller recoveries thanks to the marine push last night. These
east winds may be present Sunday and Monday night as well, but are
expected to be much weaker than Friday or Saturday night. As well as
those recoveries in the valleys tapering off through the start of
the week as that surface moisture gets eroded.
Temperatures will warm Sunday into Tuesday, which will be the
warmest day of the coming week. West side valleys in Siskiyou County
will exceed 100 degrees Tuesday and valleys in southern Oregon are
also trending towards triple digits. Dry conditions will come with
this warm up, and the day with the lowest humidities in the region
looks to be Wednesday. No anomalously strong winds are expected
during this warm up, so no critical conditions are expected.
As this period of hot and dry conditions breaks down on Tuesday, a
very low chance (< 10%) for thunderstorms is appearing across NorCal
and Lake County. This is the minority solution though, with the more
likely scenario being that the top of the ridge lingers over us and
cuts off the moisture before it reaches the region. That said, we
may still see a cumulus field bloom, but will need to monitor trends
in the moisture track before the forecast becomes more definitive.
The conditions conducive to thunderstorms will cause unstable
conditions (Haines 5 or 6) elsewhere in S. Oregon and this could
lead to larger smoke plumes developing over fires in the region that
are active and burning hotly.
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...None.
CA...None.
Pacific Coastal Waters...Small Craft Advisory until 5 PM PDT Monday for PZZ350-356-370-
376.
Gale Warning until 5 AM PDT Monday for PZZ356-376.
&&
$$
Area Forecast Discussion
National Weather Service Melbourne FL
1005 PM EDT Sat Aug 27 2022
...New UPDATE, MARINE, AVIATION...
.UPDATE...
Issued at 1001 PM EDT Sat Aug 27 2022
Current-Tonight...Widespread showers and thunderstorms occurred
throughout the afternoon across most of east central FL, with high
rain rates being the primary focus for impacts. Isolated rainfall
totals of 3-4" were observed in Orange, Seminole, Lake and Volusia
counties while the Treasure Coast overall remained relatively dry
through sunset. Current radar shows a change in this trend, with
activity winding down over the northern two thirds of the forecast
area and a line of storms building from Port Mayaca on the eastern
shore of Lake Okeechobee northeastward towards Vero Beach, with
additional activity over the Atlantic waters. While storms overnight
will not be as strong as this afternoon, heavy downpours will still
be possible, with a quick 1 to 2 inches of rain likely especially
with slow to nearly stationary storm motion. With the HRRR not even
detecting this redevelopment east of the Lake, a bit of uncertainty
exists in how long convection will sustain overnight, but anticipate
a gradual decay by midnight. Temperatures will only fall a few
degrees from current observations, reaching the mid 70s tonight.
&&
.MARINE...
Issued at 1001 PM EDT Sat Aug 27 2022
Current-Tonight...Scattered showers and thunderstorms will persist
over the Atlantic waters overnight, bringing the chance for
lightning and a small threat for gusty winds. Outside of storms,
winds SE 5-10 kts becoming S around 5 kts tonight. Seas 2-3 feet.
&&
.AVIATION...
(00Z TAFS)
Issued at 1001 PM EDT Sat Aug 27 2022
Showers and thunderstorms will continue across ECFL and will begin
to diminish around 03z. Light winds overnight, predominantly from
the S/SW. Low confidence for ground fog overnight at LEE. VCSH along
the Treasure Coast tomorrow morning for showers moving onshore.
Widespread storms are expected across ECFL in the afternoon, and
VCTS at all terminals around 18/19Z. VFR outside of convection.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 90 75 89 75 / 80 60 70 40
MCO 92 75 91 76 / 90 50 70 30
MLB 91 76 89 77 / 80 50 70 40
VRB 91 74 90 75 / 70 40 70 40
LEE 91 75 90 76 / 80 60 70 30
SFB 91 75 90 75 / 90 60 70 30
ORL 93 77 92 78 / 90 50 70 30
FPR 91 74 90 75 / 70 40 70 40
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
SHORT TERM...Smith
LONG TERM....Schaper
AVIATION...Law
Area Forecast Discussion
National Weather Service Marquette MI
620 PM EDT Sat Aug 27 2022
.SHORT TERM...(Through early Sunday morning)
Issued at 126 PM EDT SAT AUG 27 2022
GOES 16 Water Vapor channels and RAP analysis depict a shortwave
lifting from MN into Ontario. A little lower and further south, a
warm front lifting into WI supported overnight and morning
convection riding the nose of a LLJ. Through the morning hours, the
LLJ lifted into the region as shower and thunderstorm activity began
to generally to wane and split. Activity moving into MN and the
western Lake generally fell apart, while effective bulk shear
vectors supported showers and storms shifting eastward through WI.
In the wake of this initial wave, some dinural enhanced shower
activity streamed into the western UP afterwards. This has kept most
of the UP dry this morning, save for some light rain showers in the
west and western Lake Superior. Based on general radar trends and
RAP mesoanalysis, overall thinking is for the WI segment to
continue pressing eastward with its northern tail moving into the UP
while it gradually diminishes. Guidance that is handling the current
convection decently has most activity waning across the central UP
by around 3pm or so. The western shower activity is also expected to
wane.
Ahead of the precip, overcast skies filled in across the region
before the high clouds began to break. The exception so far has been
the east, which have so far enjoyed a mostly sunny morning, with
dinural cumulus developing by late morning. There, the lack of cloud
cover has allowed temps to climb into the mid-70s. Elsewhere, cloud
cover so far delayed the day`s warming, but we`re starting to see
most ob sites climb into the 70s. LLJ building into the area and
mixing has supported some gusty winds today. Highest values above 20
mph have been limited so far to the downslope areas of the West and
off the Michigamme Highlands in Marquette County. On the lake, some
high values have been reported by vessels, but these seem to be more
a factor of morning convection and not related to mixing of the LLJ.
As we progress through the remainder of the afternoon, expecting
these gusty winds to press eastward along the Alger and Luce
lakeshores.
Tonight, continued and amplifying LLJ with an approaching shortwave
from WI will support another round of precip. 12z guidance is
presenting some mixed signals, some suggesting more focused precip
further south closer to the warm front, while others bring light WAA
forced precip into the region after midnight. The CAMS present
similar situation, but the general consensus aligns more with the
latter. If this occurs, western and north central Upper Michigan,
and northern, central, and eastern Lake Superior would stand the
best chances of seeing precip.
.LONG TERM...(Sunday through Saturday)
Issued at 433 PM EDT SAT AUG 27 2022
Medium range model guidance is in good agreement on the overall
evolution of the flow across N America during the upcoming week.
Main feature of interest will be a shortwave trof currently moving
across western Canada/Pacific NW. As this feature reaches the Great
Lakes/se Canada/New England during the early thru midweek period, it
will amplify due to a building upstream ridge across the western
U.S. into the Canadian Prairie Provinces. Associated with the trof,
a fairly deep sfc low pres will develop from Manitoba into far
northern Ontario/southern Hudson Bay during the first half of the
week. Result will be an extended period of breezy winds, providing a
little preview of the upcoming windier fall season. There will be a
risk of sct shra/tsra until a pair of cold fronts passes during the
early week. Depending on how cold the air mass is that advects into
the Upper Lakes, there may be some lake effect -shra, at least into
the eastern fcst area in the Tue/Wed time period. High pres building
into the area later Wed/Thu will bring dry weather, and that will
probably last thru at least the start of Labor Day Weekend. As for
temps, expect above normal readings for the next couple of days. It
could be quite warm on Mon for some locations. Temps will fall back
blo normal for midweek. Wouldn`t be surprised to see some frost in
the interior on one morning if sfc high pres ends up passing over
the area during a nighttime period. Temps will transition back to
above normal heading into the Labor Day Weekend. Looking farther
ahead, there has been a consistent signal in CFSv2 runs and medium
range ensembles for warm weather over the Labor Day weekend and into
the first full week of Sept as ridging/expansive positive height
anomalies develop from sw Canada into ne Canada. This pattern should
also favor overall dry weather/limited chances of pcpn.
Beginning Sun, there may be a few shra/tsra across the area Sun
morning on the eastern edge of low-level jet axis, but with main
push of 850mb theta-e advection already shifting n of the area, pcpn
potential will be diminishing during the morning. Otherwise,
during Sun, a shortwave will be lifting ne across the Upper
Mississippi Valley to the Upper Great Lakes. This feature should
support some shra/tsra development in the mid to late aftn and
evening hrs. Much of the model guidance has MLCAPE under 700j/kg
in the aftn with deep layer shear under 30kt. In addition, model
fcst soundings indicate a skinny CAPE profile. So, at this point,
don`t anticipate a svr storm risk with the aftn/early evening
storms. Southerly winds up Lake MI will lead to mdt swim risk for
the beaches of Schoolcraft County. If winds are slightly stronger
to further increase wave action, there will be a high swim risk.
Stronger shortwave and an associated cold front will swing e toward
Upper MI Sun night. Tsra, some strong/svr, should develop along the
front in MN late Sun aftn/evening, taking advantage of an axis of
higher MLCAPE and 30-40kt of deep layer shear. Being sfc based,
these storms should be starting the decaying phase as they spread
into Upper MI late evening or more likely overnight. Should the
decay phase be delayed, there will be a risk of an isolated svr
storm into western Upper MI. Ahead of this convection, increasing
low-level jet and modest surge of 850mb theta-e could trigger an
arc/waa wing of sct elevated convection that will lift ne over
portions of the fcst area. With winds stirring and a moist column
(precipitable water 150-175pct of normal), it will be a warm late
Aug night. Expect lows in the 60s with some downslope areas near
Lake Superior only falling to 70F.
Some redevelopment of storms could occur over the eastern fcst area
on Mon as lake breeze components sharpen up convergence along
passing cold front, but timing of fropa will be key, and that won`t
be more certain until we get closer to that time period. With deep
layer shear in excess of 35kt and initial model MLCAPE of at least
1000j/kg, there will be a risk of svr storms if fropa is delayed to
allow for renewed storm development. To the w, cooling column,
cyclonic flow and shortwave dropping into the Upper Mississippi
Valley should support development of sct shra, maybe a tsra, into
western Upper MI late in the aftn. CAA is on the weak side on Mon
after first fropa, and with breezy w to sw winds, expect a warm day
with high temps in the 80s F for much of the area, mid 80s F
possible for the downslope areas over central Upper MI. Mixing
potential per fcst soundings suggests wind gusts of 20-30mph should
be fairly common.
Colder air arrives Tue and especially on Wed. CMC/ECMWF/GFS
ensembles show median 850mb temps down to about 4 to 7C, lowest over
eastern Lake Superior, though 12z ECMWF ensemble median has trended
warmer. With western Lake Superior water temps running generally
around 17C and with eastern Lake Superior water temps from the lee
of the Keweenaw toward Whitefish Pt up to 19C (water quite a bit
colder farther out in the lake) there will be the potential of some
lake effect -shra into at least the eastern fcst area, particularly
if there is assistance from any shortwaves dropping into the
amplifying eastern trof. Expect breezy conditions to continue
Tue/Wed (gusts 20-30mph). Gusts to 40+mph will be possible on the
Keweenaw Tue.
With one possible exception, dry weather will round out the fcst for
Thu-Sat with warming getting underway. There are some indications
that a shortwave tracking eastward into northern Ontario on Sat may
push associated cold front into the northern Great Lakes. Would
expect limited moisture to result in minimal potential of any -shra
if the front does drop into Upper MI.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 620 PM EDT SAT AUG 27 2022
VFR conditions are expected to prevail at all sites during this TAF
period. LLJ across the area will continue to support gusty winds of
20 to 25kts tonight. Additionally, LLWS is expected at IWD tonight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 433 PM EDT SAT AUG 27 2022
Breezy conditions will mostly prevail across Lake Superior into the
middle of the upcoming week as fairly deep low pres tracks e toward
far northern Ontario/southern Hudson Bay. Southerly winds will gust
to 20-30kt tonight with the stronger gusts mostly at higher obs
platforms and in some of the nearshore waters of Upper MI where
downslope off terrain aids increased winds. Winds will diminish a
bit on Sun, more notably over western Lake Superior. Expect an
increase in southerly winds again Sun night, mainly over eastern
Lake Superior where gusts to around 25kt return. Passing cold front
will then bring a transition of stronger winds to the w half of Lake
Superior for Mon. Expect w to sw winds gusting to 25-30kt there.
Winds will diminish some over eastern Lake Superior. Arrival of
colder air will then lead to w to nw winds gusting to 25-30kt across
most of Lake Superior by later Mon night, continuing thru Tue and
into Wed. Not out of the question that there could be some gale
force gusts to 35kt at times. Arrival of high pres for Thu will lead
to light winds under 20kt at that time.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JTP
LONG TERM...Rolfson
AVIATION...07
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Phoenix AZ
435 PM MST Sat Aug 27 2022
.UPDATE...
Updated Aviation
&&
.SYNOPSIS...
The weather pattern will shift into a drier regime through the
weekend with chances for showers and thunderstorms gradually
lowering, then migrating exclusively into higher terrain regions.
Storm activity early next week may be extremely limited before
better moisture possibly begins to return during the latter half of
the week. Temperatures will hover slightly below normal through the
weekend before a warming allows for above normal temperatures to
return next week.
&&
.DISCUSSION...
High pressure remains centered south of the international border,
promoting continued westerly flow aloft over our region. Given the
flow aloft, drier air continues to advect into the region with this
morning`s 12Z PHX sounding recording a PWAT value of 1.49".
Nevertheless, sufficient enough moisture and instability is expected
today to lead to some showers and thunderstorms this afternoon and
evening across the region. In fact, current radar showed isolated
showers/thunderstorms already developing across parts of Maricopa
County as well as parts of La Paz County. Areas across the high
terrain will stand the best chances for seeing additional shower and
thunderstorm development through the afternoon and evening. The
westerly steering flow will be unfavorable for thunderstorms moving
into the Valley from the high terrain. However, orographic lift
along lower desert terrain features as well as the potential
influence of a weak disturbance near northern Baja may aid in some
additional showers and thunderstorms developing across the lower
elevations.
The latest HRRR and 12Z HREF favor continued development across much
of the state through the afternoon as diurnal heating leads to
increasing destabilization. Across southwest Arizona, HiRes guidance
shows little in the way of thunderstorms today, aside from ongoing
development along the Kofas. Further west across southeast
California, chances look to remain very low (~5%) for showers and
thunderstorms. There are indications that a few isolated
thunderstorms may develop in northern Baja and potentially extend up
into eastern Imperial County. Modeled soundings indicate high DCAPE
values today climbing upwards of 1,500-2,000 J/kg this afternoon.
This will promote the potential for a few strong/severe wind gusts.
The HREF shows upwards of a 50-70% chance for outflow winds to climb
in excess of 35 mph across parts of south-central Arizona. The
probability of gusts in excess of 58 mph is less than 10%.
Continued deep westerly flow will advect additional dry air with
storm chances further waining Sunday, likely confined completely to
the higher terrain. Storm chances decline to near zero areawide
starting Monday due to these factors and enhanced subsidence from
upper level ridging. In fact, many ensemble members show 500 hPa
heights rising upwards of 594-595 dm by Tuesday, near the 95th
percentile for this time of year. Temperatures will rise above
normal with highs potentially exceeding 110F for much of the lower
deserts and potentially upwards of 110-115 across southeast
California. Given the temperatures expected, moderate to locally
high HeatRisk is expected by midweek across the lower deserts and
may lead to excessive heat conditions being met.
By the middle of next week the anomalous high pressure area will
settle over the Great Basin with east to northeast midlevel flow
developing. Meanwhile, lower level water vapor may tick up just
slightly due to lower level southerly flow. This could allow for an
uptick in storm activity once again, but for now ensemble guidance
is mostly minimal with fairly lackluster QPF. Ensemble guidance
continues to show some uncertainty with respect to any easterly
waves, but overall guidance has consolidated around the idea of
keeping any such waves too far to the south to really impact the
weather for the desert southwest. NBM Pops do pick up a bit, peaking
at 5-20% in the valleys (highest values to the east) and 20-30% in
the higher terrain. With limited storm (and cloud) activity, high
temperatures will likely stay elevated at 105-110 for the lower
deserts.
&&
.AVIATION...Updated 2335Z.
South-Central Arizona including KPHX, KIWA, KSDL, and KDVT:
Isolated TS and multiple outflow boundaries/wind shifts through
early this evening will be the main weather hazard through. TSRA
clusters were hovering over KIWA, as well as outside KPHX western
visual ranges late this afternoon with a tendency for weakening and
not directly impacting terminals (less than a 20% chance the
remainder of the evening). However, multiple outflows were floating
around the Phoenix area creating erratic directions and odd wind
shifts. While some form of a southerly wind could impact KPHX, the
eventual trend will be towards northeast winds later in the evening
and overnight. Convective activity should be even more sparse Sunday
afternoon with less than a 10% chance of impacts to Phoenix sites.
Southeast California/Southwest Arizona including KIPL and KBLH:
No weather issues should exist through Sunday afternoon with storm
activity remaining east of terminals. Southerly winds will be
favored the majority of the period with typical diurnal variations
between SE and SW. A few gusts 15-20kt will be possible during the
late afternoon/evening hours.
&&
.FIRE WEATHER...
A gradual decline in storm chances will continue, but the high
terrain north and east of Phoenix should remain fairly active today
with a modest (40%) chance of thunderstorms. Gusty winds will be
possible with any storms. Substantial drying will spread across the
area starting Sunday, essentially ending rain chances across the
lower deserts and then likely even over the Arizona high terrain for
early next week. MinRH values will generally remain in a 30-35%
range over lower elevations to 40-50% over the higher terrain
through Sunday, before lowering starting Monday. Apart from
thunderstorms, winds will follow familiar diurnal patterns. A chance
of higher terrain storms will resume by mid week.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...None.
CA...None.
&&
$$
DISCUSSION...Smith/Hodges
AVIATION...18
FIRE WEATHER...Hodges
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
816 PM EDT Sat Aug 27 2022
...New UPDATE, AVIATION, MARINE...
.UPDATE...
Issued at 816 PM EDT Sat Aug 27 2022
Slow moving showers and thunderstorms continue along numerous
outflow boundaries across much of west central Florida. Earlier
intense thunderstorm activity has diminished, but coverage is
still rather high. The heaviest rains are now mostly from Pasco
county north through Citrus and Levy counties.
The HRRR did a pretty good job showing renewed activity in the
Tampa Bay area this evening, so relied fairly heavily on that
guidance to show most areas rain free after midnight with showers
and storms moving slowly westward through the nearshore Gulf
waters. Look for light east to southeast flow overnight to become
more southerly again by Sunday afternoon with showers and storms
developing along both east and west coast sea breezes. Similar to
today, expect initial shower and thunderstorm development along
bay and gulf breezes early Sunday afternoon to move inland as the
day progresses. Late in the afternoon or early evening, showers
and storms could again move back toward the coast and linger
through midnight or so.
&&
.AVIATION...
(00Z TAFS)
Issued at 816 PM EDT Sat Aug 27 2022
Expect showers and perhaps a few storms along outflow boundaries
through 03Z or so, then VFR overnight. Showers and storms are
likely again on Sunday, especially after 18Z.
&&
.MARINE...
Issued at 816 PM EDT Sat Aug 27 2022
Generally light winds and slight seas expected through Sunday as
high pressure remains nearby. The ridge of high pressure will move
north next week resulting in south to southeast winds around 10
knots with onshore winds near the coast each afternoon. Winds and
seas will be locally higher in the vicinity of thunderstorms.
&&
.FIRE WEATHER...
Issued at 125 PM EDT Sat Aug 27 2022
Summertime humidity and warm temperatures continue with no fire
weather concerns.
&&
.PRELIMINARY POINT TEMPS/POPS...
TPA 79 91 78 91 / 60 50 50 90
FMY 77 92 77 92 / 50 70 50 90
GIF 76 91 76 92 / 60 70 30 90
SRQ 75 90 75 90 / 60 50 50 90
BKV 73 91 73 91 / 60 70 40 90
SPG 78 89 78 90 / 60 50 50 90
&&
Sea Breeze Thunderstorm Regime For Sunday: 1
Sea Breeze Thunderstorm Regime For Monday: 6
For additional information on sea breeze regimes, go to:
https://www.weather.gov/tbw/ThunderstormClimatology
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...Jillson
PREVIOUS FIRE WEATHER DISCUSSION...Noah
DECISION SUPPORT....Flannery
UPPER AIR...Zayas
Area Forecast Discussion
National Weather Service Tulsa OK
651 PM CDT Sat Aug 27 2022
...New SHORT TERM...
.SHORT TERM...
(The rest of tonight)
Issued at 651 PM CDT Sat Aug 27 2022
A broken band of thunderstorms extends from central KS southwest
into the TX Panhandle late this afternoon in association with an
upper wave. This activity will continue east overnight across
northern OK. While the latest runs of the HRRR suggest this
activity will weaken before it enters northeast OK late tonight, a
strengthening LLJ and increasing warm/moist advection suggests
storms may linger longer than HRRR indicates. Updated forecast
with latest hourly NBM (consensus guidance) PoPs, which are more
aggressive in bringing rain/storm chances into northeast OK (north
and west of Tulsa) before 12Z. PoPs decrease after 12Z as the LLJ
weakens/veers for a time, before diurnal heating increases storm
coverage later in the day Sunday.
Lacy
&&
.LONG TERM...
(Tonight through Saturday)
Issued at 213 PM CDT Sat Aug 27 2022
The latest data suggests the activity on Sunday will pose the
greatest threat for locally heavy rainfall as the near 2" PWAT
axis in association with the upper trof slides overhead. With
500mb flow increasing to near 20kts with the wave, a few strong
storms are possible with daytime heating, with isolated severe
downbursts possible. Shower and storm coverage should gradually
decrease Sunday night, though it`s not out of the question there
could be isolated heavy rain in spots. Forecast highs Sunday were
adjusted downward from the blended guidance (NBM) forecast by a
couple degrees given uncertainties regarding cloud cover and rain
coverage. The NBM forecast was near the top of the guidance suite.
Scattered showers and storms are expected to linger into Monday
morning along the trailing deep layer moist axis left behind from
the departing wave.
A strong shortwave trof is expected to traverse the northern tier
of states early this week and eventually carve out a deep trough
over eastern Canada and the Great Lakes by midweek. This system
will force a frontal boundary south down the Plains. By Monday
afternoon, this front is expected to extend across KS per the
GFS/NAM. With the frontal forcing for storms expected to stay to
our north during the day Monday, we may just have spotty showers
and storms over our area. The likely PoPs from the NBM probably
stemmed from 00Z EC are overdone per GFS/NAM and were adjusted
downward. Monday evening PoPs were adjusted upward a touch near
the KS border to account for some potential for storms along the
front to come south. The GFS suggests there is potential for
another round of storms to be focused along the front Tuesday
afternoon across the area, and thus chance PoPs were maintained
thru the afternoon for most places. Deep layer dry air behind the
front will yield tranquil weather for the middle to latter part of
next week.
Lacy
&&
.AVIATION...
(00Z TAFS)
Issued at 624 PM CDT Sat Aug 27 2022
Widely scattered showers or a stray thunderstorm remain possible
for another hour or two across SE OK and WC AR, with only a
minimal threat of impacts at KFSM/KMLC. The chance for showers and
thunderstorms will increase late tonight from the west with some
degree of storm chances persisting through Sunday afternoon.
Overall VFR conditions are expected to prevail, though there will
be a slime probability of MVFR conditions should storms directly
impact TAF sites.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 75 91 75 93 / 30 40 30 50
FSM 75 92 74 92 / 10 40 30 50
MLC 73 92 73 92 / 10 30 10 50
BVO 73 92 70 94 / 50 50 30 40
FYV 71 87 70 89 / 10 50 30 50
BYV 71 87 71 89 / 10 40 20 50
MKO 72 90 72 89 / 10 40 20 50
MIO 72 90 71 92 / 20 50 30 50
F10 72 90 72 92 / 10 50 20 50
HHW 72 92 73 89 / 20 20 10 40
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...30
LONG TERM....30
AVIATION...14
Area Forecast Discussion
National Weather Service Las Vegas NV
728 PM PDT Sat Aug 27 2022
.SYNOPSIS...Drier conditions with sparse thunderstorm activity
will continue over the weekend. High pressure will build over the
Great Basin next week with temperatures climbing several degrees
above normal and fairly limited thunderstorm activity persisting.
&&
.UPDATE...Much drier air has spread into the region with
afternoon Las Vegas sounding observing 0.62" precipitable water,
down from 0.97" this morning. Feeling more comfortable with
dewpoints in the mid 30s in Las Vegas. Dewpoints have fallen into
the mid 40s at Kingman. However, not all areas seeing those lower
dewpoints with Colorado City currently in the mid 60s and
Needles/Lake Havasu City hovering in the mid 50s. Quiet rest of the
evening and overnight in store.
00Z HRRR shows isolated shower/t-storms across Mohave County Sunday
afternoon and evening. Some guidance suggests some low level
moisture return into northeast San Bernardino and southern Clark
Counties for potential build-up Sunday. Will be monitoring
dewpoints/PW values as well as hi-res simulation trends overnight.
For now, no update necessary this evening.
&&
.SHORT TERM...through Sunday night.
As expected, thunderstorm activity is quite limited this afternoon
with the only radar returns currently over the Arizona Strip near
the Mt Trumbull wilderness area and far eastern Lincoln County.
Expecting activity through this evening to remain fairly sparse
and limited to eastern Mohave and Lincoln Counties, thanks to
drier air working in from the west and some modest mid-level
capping keeping instability in check. Meanwhile, warm temperatures
have returned with Las Vegas already reaching 101 as of this
writing, which is coincidentally the average high for the date,
and we still have several more hours of heating in store.
Similar conditions continue tomorrow, though a nudge of deeper
surface moisture will creep back up the Colorado River Valley
overnight. This increased moisture will help knock high temps down
a few degrees from the I-15 corridor southward, with lesser
influence across our Great Basin zones further north.
Additionally, the modest increase in moisture may help spark a few
isolated showers and storms, mainly in the higher terrain of San
Bern, Clark, and Mohave counties by the afternoon.
.LONG TERM...Monday through Friday.
After being nudged southward over the weekend, high pressure will
begin to rebuild next week and expand across the Great Basin. This
will result in an upward trend in temperatures, with highs
climbing several degrees above normal by midweek. The current NBM
forecast for Las Vegas suggests a high temperature of 108F, which
would be the warmest temperature since July 22nd (5 weeks ago!).
This magnitude of heat also bumps most of the desert valleys into
moderate to high heat risk Tuesday through Thursday, so excessive
heat headlines are certainly possible.
The outlook remains fairly dry next week as monsoonal moisture
stays limited due to an unfavorable orientation of high pressure
over the Great Basin. However, some hints at a return of deeper
moisture are suggested by the end of next week that bears
watching.
&&
.AVIATION...For Harry Reid...No significant weather is in store for
the terminal area through the weekend as dry and stable air spreads
over southern Nevada. E-SE winds will become S-SW 12G20KT after 20Z
then SW less than 10KT early this evening and overnight. Only a few
clouds expected around 12k feet. Conditions are expected to remain
nearly the same on Sunday.
For the rest of southern Nevada, northwest Arizona and southeast
California...No significant weather is expected for TAF sites as dry
and stable air spreads over most of the region and keeps isolated
thunderstorms confined over northwest Arizona and near the NV/UT
border. S-SW winds will develop this afternoon with speeds 12G20KT
for most sites then speeds decreasing below 10KT this evening and
overnight. Conditions are expected to remain nearly the same on
Sunday with any thunderstorm activity remaining over NW Arizona.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
UPDATE...Pierce
DISCUSSION...Outler
AVIATION...Gorelow
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