Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
348 PM EDT Wed Sep 24 2025

Valid 12Z Sat Sep 27 2025 - 12Z Wed Oct 01 2025

...Heavy rain threat continues across the Southwest through the
weekend...

...Overview...

An upper trough/low over the Southeast will be slow to dislodge
through the period due to a large Bermuda High anchored over the
Atlantic. Northern stream shortwaves near the Canadian border will
be much more progressive. An upper low over southern California
will shift slowly through the Southwest U.S. this weekend and
weaken as it lifts towards the High Plains. A ridge in between
these two upper lows will strengthen early next week with an
amplified upper trough approaching the West Coast. Heavy rainfall
threats this weekend will focus mostly over the Southwest ahead of
the upper low, as well as the Carolinas/Appalachians near a
stationary coastal front. Increasing and more widespread
precipitation will spread into much of the West next week with snow
possible in the highest elevations. Today's guidance shows more
agreement on steering a pair of tropical systems off the coast of
the southeast U.S. However, a high degree of uncertainty remains on
how the two systems may interact with the upper trough/low over
the Southeast and the potential impacts they may bring to land.


...Guidance/Predictability Assessment...

The latest guidance continues to show good agreement on the large
scale synoptic set up through at least the first half of the
period, but still with some uncertainty in the details. The biggest
and potentially most impactful area of uncertainty remains the
Southeast and western Atlantic as a pair of potential tropical
lows
round the west side of the Bermuda High and pass somewhere between
the East Coast and Bermuda. The Southeast upper trough may tend to
steer the tropical systems away from the coast, but more complex
interactions between the Southeast upper-trough/low and the
tropical system(s) leading to impacts along the coast of the
southeastern U.S. cannot be ruled. Refer to the tropical weather
outlook from the National Hurricane Center for the latest on these
systems of concern.

Out West, the guidance shows a slightly faster eastward ejection of
the Southwest upper-low/trough, which leads to a slightly more
eastward placement of the heaviest QPFs across New Mexico.
Meanwhile, amplified troughing looks to overtake the western U.S.
by the end of the period with uncertainties on the timing of
individual shortwaves/energy embedded within it.

The WPC forecasts today is based on the consensus of 40% from the
06Z GFS/GEFS, 40% from the 00Z ECMWF/EC mean, and 20% from the 00Z
CMC/CMC mean with a higher percentage from the ensemble means for
the latter half of the forecast period. This overall maintains
good continuity with the previous shift.


...Weather/Hazards Highlights...

A frontal boundary lingering along the East Coast will support
daily showers and storms especially for the Mid-Atlantic states
into next week. Anomalous moisture with a possible tropical
connection will maintain at least a localized heavy rainfall threat
for particularly the Carolinas and southern/central Appalachians.
Marginal risk areas are maintained on the Days 4 and 5 (Saturday
and Sunday) Excessive Rainfall Outlooks for this region. The threat
may continue into next week with potential for additional moisture
associated with possible tropical systems to monitor.

Meanwhile, Pacific moisture ahead of an upper low over southern
California will result in increasing rainfall chances continuing
this weekend across much of the Southwest into California. Moisture
anomalies 2 to 3 standard deviations above normal and sufficient
instability will result in at least a localized flash flood threat,
particularly for vulnerable burn scar areas. This region remains
highlighted with a marginal risk for both Friday and Saturday EROs
with a more targeted slight risk on Day 4 across southeast Arizona
to southwest New Mexico and on Day 5 across central New Mexico
where QPF amounts are greatest. The activity will shift slowly
eastward with time and should begin to taper off by Monday.

Precipitation will increase by next week across the Northwest U.S.
associated with amplified troughing over the region. Widespread
rain is expected across the Pacific Northwest and into the northern
Great Basin/Rockies. The heaviest precipitation is expected from
western Washington to northern California and the Sierra Nevada.
Some snow may fall in the highest elevations of the West.

Warmer than average temperatures will slowly shift from the
Northwest this weekend into the Northern Plains as upper ridging
builds over the region next week. Daytime highs could be 10-15
degrees above normal for some locations. Below normal temperatures
over the Southwest will expand northward along much of the West
Coast by next week.

Kong/Santorelli


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
345 PM EDT Thu Sep 25 2025

Valid 12Z Sun Sep 28 2025 - 12Z Thu Oct 02 2025

...Heavy rain threat continues through Sunday for the Southwest...

...Tropical Disturbance may bring tropical impacts to the
Southeast
and Mid-Atlantic next week...


...Overview...

An upper trough/low will remain stalled over the Southwest through
Sunday, blocked by strong ridging downstream. A deep upper low and
trough will move towards the West Coast early next week, lifting
the upper low out of the Southwest and increasing precipitation
chances across the West. The Central U.S. will remain mostly dry
through the period under the influence of high pressure ridging,
but the Eastern U.S. may be entering a wetter pattern. A cold front
will move across the Northeast Sunday into Monday while a
stationary front lingers along the Southeast and Mid-Atlantic
coasts. There may be a chance for heavy rainfall and flash flooding
over portions of the Southeast and Mid-Atlantic Monday through
Wednesday, but that will depend on the evolution of a likely
tropical low forming near the Bahamas over the next few days.


...Guidance/Predictability Assessment...

Model guidance continues to show good agreement on the large scale
synoptic pattern through the medium range period, with some
differences over the East and West Coasts.

The most impactful are of uncertainty will be over the Eastern
U.S. where a tropical low may create hazardous weather for the
Carolinas and the Mid-Atlantic next week. Most guidance has
clustered around two solutions, either bringing the tropical low
north into the Carolinas or stalling offshore and being swept out
into the Atlantic. The evolution will ultimately be determined by
interactions between the tropical low, Hurricane Humberto to the
east, a frontal boundary to the north, and an upper trough over the
East. WPCs afternoon forecast reflects the solution that brings
the low into the Carolinas Monday into Tuesday, which is in line
with the National Hurricane Center's (NHC) approach to the system
as well. This was a large shift from the overnight forecast,
resulting in significantly higher precipitation totals over the
Mid-Atlantic and Southeast. Please refer to the NHC for the latest
information on this system. There is still a large amount of
uncertainty surrounding the evolution and track of this low, and
the forecast will likely change over the next few days.

For the West, the uncertainty comes from timing and evolution
differences of low pressure systems moving onshore from the
Pacific. This uncertainty will affect precipitation location and
amounts near the Coast, especially Monday into Tuesday when locally
heavy precipitation will be possible.

WPC's afternoon forecast for Sunday through Tuesday was based on a
blend of the 00Z ECMWF/CMC/UKMET and 06Z GFS. Given relatively good
agreement, this provided a good middle ground starting point. For
Wednesday and Thursday, ensemble means from the 06Z GEFS and 00Z
ECENS were added in increasing amounts to smooth out model
differences.


...Weather/Hazards Highlights...

A frontal boundary lingering along the East Coast will support
daily showers and storms, especially for the Mid-Atlantic states,
through early next week. Anomalous moisture with a possible
tropical connection will maintain at least a localized heavy
rainfall threat for the Mid-Atlantic/Carolinas and parts of the
Appalachians. There will be a Marginal Risk of excessive rainfall
over eastern Virginia, North Carolina, and South Carolina on
Sunday, and another Marginal Risk for most of the Mid-Atlantic and
Carolinas on Monday. With increasing potential for tropical
moisture leading to enhanced precipitation in the Carolinas on
Monday, a Slight Risk of excessive rainfall was introduced for
portions of the Carolina Coasts. The threat may continue beyond
Monday depending on the evolution of the tropical systems off the
Southeast coast, and there are pieces of guidance suggesting
significantly higher rainfall amounts will be possible. The
rainfall forecast will likely change over the next few days.
Regardless of how the rainfall forecast turns out, the Southeast
Coast will likely experience dangerous surf and rip current
conditions early next week, and some areas may experience increased
winds.

To the west, Pacific moisture ahead of an upper low over southern
California will result in rainfall continuing into Sunday, though
with lesser intensity than the short range. Anomalous moisture and
sufficient instability will continue to support at least a
localized flash flood threat Sunday into Monday, particularly for
vulnerable burn scars. This region remains highlighted with a
Marginal Risk of excessive rainfall for both Sunday and Monday,
with
a more targeted Slight Risk on Sunday across central New Mexico
where QPF amounts are greatest.

Precipitation will increase by next week across the Northwest U.S.
associated with amplified troughing over the region. Widespread
rain is expected across the Pacific Northwest and into the northern
Great Basin/Rockies. The heaviest precipitation is expected from
western Washington to northern California and the Sierra Nevada. A
Marginal Risk of excessive rainfall was added for Monday for
northern California. Some snow may fall in the highest elevations
of the West as well.

Warmer than average temperatures will shift into the Northern
Plains and maintain as upper ridging builds over the region next
week. Daytime highs could be 10-20 degrees above normal for parts
of the Upper Midwest. Below normal temperatures over the Southwest
will expand northward along much of the West Coast by next week.


Dolan/Santorelli


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
451 PM EDT Fri Sep 26 2025

Valid 12Z Mon Sep 29 2025 - 12Z Fri Oct 03 2025


...Potential Tropical Cyclone 9 may bring tropical impacts to the
Southeast and Mid-Atlantic next week...

...Overview...

The upper level pattern will feature mean troughing over the West,
low pressure over the Southeast, and narrow ridging in between.
This pattern will support enhanced precipitation chances in the
West and Southeast, with chances for heavy rain that could lead to
flash flooding. The highest area of concern will be portions of the
Southeast and Mid-Atlantic that may be impacted by Potential
Tropical Cyclone 9 next week. However, the forecast for these
regions is highly uncertain given high uncertainty in the forecast
track of the system. Most of the Central U.S. and Northeast will
remain dry through the period under the influence of high pressure.
Precipitation chances may increase later next week across the
norht-Central U.S. as a frontal boundary moves across the West and
emerges in the Plains.


...Guidance/Predictability Assessment...

Model guidance is generally in agreement on the large scale upper
level pattern with some uncertainty surrounding features
approaching the West and East Coasts. In the West, there is
increased agreement on the evolution of the upper trough moving
inland, but there are differences in how individual models handle
shortwave energy moving through the trough. This has led to
differences in the evolution of Pacific frontal systems moving
onshore. For now, it seems like a middle of the road solution
worked best to represent potential timing and position of these
systems.

The forecast is much more complicated for the East given a high
amount of uncertainty surrounding the evolution of Potential
Tropical Cyclone 9, which is currently forecast to move towards
the Southeast Coast while strengthening next week. Some models
bring the tropical system inland in the Carolinas, some stall the
system right over the Carolina coast, and some stall the system
further away from the coast before swinging the system out into the
Atlantic. The ultimate evolution will depend on the system's
interactions with Hurricane Humberto to the east and high pressure
strengthening to the north. If the strong high shifts east, the
system could move inland, but if the high remains due north, a
stalled solution would be favored. After coordinating with the
National Hurricane Center, the current forecast thinking is to
stall the system very close to the Carolina coast. This solution is
similar to the 00/12Z ECMWF solutions and may result in a
prolonged heavy rainfall event for coastal areas of the Carolinas.

WPC's afternoon forecast blend was comprised of the 00Z
ECMWF/CMC/UKMET and 06Z GFS, with heavier weight placed on the
ECMWF and GFS than the CMC and UKMET, for Monday through Wednesday.
By Thursday and Friday, ensemble means from the GEFS and ECENS were
added in increasing amounts, making up to 60% of the blend, which
helped to smooth out large differences in the deterministic
models.


...Weather/Hazards Highlights...

Showers and thunderstorms will be possible near a lingering
frontal boundary over the Mid-Atlantic and Southeast early next
week. Anomalous moisture associated with Potential Tropical Cyclone
9 will maintain precipitation chances, with a heavy rain and flash
flood threats, through mid-week. The highest risk of flash
flooding will likely focus over the coastal Carolinas, but rainfall
amounts are highly uncertain and will depend on the track of the
system. Some models suggest much higher rainfall amounts are
possible while some suggest lower amounts. For now, there is a
Marginal Risk of excessive rainfall across the Carolinas and
Virginia with a Slight Risk for the eastern Carolinas and
southeastern Virginia on Monday and Tuesday. If the system moves
inland at all, there may be enhanced precipitation over upslope
areas of the Appalachians that would lead to a higher flash flood
risk. The heavy rain and flash flood threats may continue beyond
Tuesday if the system stalls near the coast, with precipitation
chances extending through Thursday and Friday. Regardless of how
the rainfall forecast turns out, the Southeast Coast will likely
experience dangerous surf and rip current conditions early next
week, and some coastal areas may experience strong winds.

Pacific moisture ahead of the upper trough will result in
continued rain chances for the West Coast and Intermountain West on
Monday and Tuesday. Precipitation may be enhanced over northern
California and southern Oregon as a slow-moving frontal system
moves onshore, resulting in localized flash flooding chances and a
Marginal Risk of excessive rainfall on Monday and Tuesday.
Precipitation chances should decrease on Wednesday and Thursday,
but precipitation will likely linger over the Pacific Northwest and
northern Rockies. Precipitation chances may also increase later
next week across the north-Central U.S. once the frontal system
pushes across the mountain and emerges in the Plains.

Warmer than average temperatures will persist across the Northern
Plains as upper ridging builds over the region next week. Daytime
highs could be 10-20 degrees above normal for parts of the Upper
Midwest. Below average temperatures are expected across much of the
West and Southeast due to upper troughing and potential rainfall.


Dolan


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
357 PM EDT Sat Sep 27 2025

Valid 12Z Tue Sep 30 2025 - 12Z Sat Oct 04 2025


...Tropical Depression Nine will bring tropical impacts to the
Southeast/Carolinas next week...

...Overview...

The path and impacts of Tropical Depression Nine will be a primary
forecast concern into next week. The current forecast track shows
Nine stalling just offshore in the western Atlantic but providing
rain and possible flooding to at least the coastal Carolinas for
the start of the medium range period Tuesday. There remains ample
uncertainty in rain amounts especially farther inland, which depend
on the uncertain track of the system influenced by Hurricane
Humberto to its east, cool surface high pressure in the Northeast,
and a northern stream trough. Farther west, mean upper ridging is
forecast to set up from the Southwest northeastward into the
Midwest promoting warm temperatures and mainly dry conditions.
Meanwhile the West can expect mean troughing with cooler
temperatures and rounds of precipitation.


...Guidance/Predictability Assessment...

WPC follows the National Hurricane Center (NHC) track for T.D.
Nine, which shows the strengthening tropical cyclone remaining
offshore in the western Atlantic but close enough to land to bring
heavy rainfall to the Carolinas Tuesday. Recent deterministic model
guidance from the 00/06Z cycle and the new 12Z cycle is agreeable
with this type of track showing no landfall through midweek.
However, there are still ensemble members from the GEFS/EC/CMC
ensembles and the AI/ML Google DeepMind and AIFS ensembles that
show a landfalling system, so coastal areas may not be out of the
woods for landfall yet. For the WPC forecast, used the
ECMWF/CMC/AIFS through around midweek for QPF and background model
data with the NHC points for the system. The incoming 12Z guidance
continues to indicate splitting model guidance, with the new 12Z
CMC much faster in turning the cyclone east than its 00Z run, the
12Z GFS slowing down somewhat (more favorably with the NHC track),
and the 12Z ECMWF slowing it down considerably where it stalls/does
not get taken east even into later week. Continue to monitor NHC
forecasts for further details and updates to the track and timing
of Nine.

Elsewhere, models are generally agreeable on the large scale with
the mean trough in the West slowly moving eastward with less
certain shortwaves moving through and pushing fronts through the
region, but the spread is typical for the medium range time frame.
Additionally, the elongated upper ridge shows reasonable consensus
as it stretches from the Southwest across parts of the central U.S.
into the Ohio Valley and eventually the Northeast. Weak energy may
cut off from this ridge in the southern stream over the Southeast
or so, with more uncertainty. Overall across the lower 48, a multi-
model blend of mainly deterministic guidance was used for the
early to mid medium range period, with increasing proportions of
the GEFS and EC ensemble means during the latter period.


...Weather/Hazards Highlights...

The Carolinas can expect wet and unsettled conditions into Tuesday
as T.D. Nine approaches with its anomalously high tropical
moisture and its interaction with a lingering stationary front.
Heavy rain and flash flooding are threats with this system, with
highest rainfall totals particularly along coastal areas. It is
more uncertain how much rain will reach farther inland. Marginal
and Slight Risks were maintained in the Day 4/Tuesday ERO, with
some minor shifts based on newest guidance like trimming out the
northern side of the previous issuance of the Slight (taking it out
of southern Virginia). Most of the recent guidance and the NHC
track takes the system farther east by Day 5/Wednesday for less of
a rainfall threat by then, so removed the Marginal Risk at this
time and will see how future forecasts evolve. In addition to
rain/flooding threats, the Southeast Coast will likely experience
dangerous surf and rip current conditions into Tuesday, and some
coastal areas may experience strong winds. Then scattered showers
and storms are possible in Florida and into the Gulf Coast through
much of the week.

A weak atmospheric river is forecast to push across the Pacific
Northwest into California on Tuesday and Wednesday with a cold
front ahead of the upper trough. Rain totals generally under an
inch or two do not appear to cause hazardous conditions in the
coastal mountain areas that are accustomed to seeing multiple
inches of rain. Rain could continue in the West Coast states
through Thursday with another front. Rounds of precipitation will
be likely across parts of the Intermountain West/Rockies through
multiple days next week, and the higher elevations can expect snow.
Precipitation chances may also increase later next week across the
north-central U.S. once the frontal system pushes across the
mountain and emerges in the Plains.

With upper ridging building overhead, warmer than seasonal average
temperatures are expected across the central U.S., especially for
the Northern Plains to Upper Midwest. Highs of 10 to 20 degrees
above normal will be common in those areas, with highs of 80F
reaching to the Canadian border Tuesday-Wednesday. 90s are likely
to continue for early October into the Desert Southwest and Texas.
Meanwhile, below normal temperatures especially for highs are
likely across the West due to upper troughing and rainy/cloudy
conditions.


Tate


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
358 PM EDT Sun Sep 28 2025

Valid 12Z Wed Oct 01 2025 - 12Z Sun Oct 05 2025


...Overview...

As there is better consensus for Imelda to curve east away from the
U.S. before midweek, attention turns to other forecast aspects
during the medium range period. A relatively slow-moving and blocky
pattern will set up across the U.S., with mean troughing in the
West promoting frontal passages with cooler temperatures and rounds
of precipitation, while an upper ridge sets up from the Southwest
northeastward into the Midwest promoting warm temperatures and
mainly dry conditions. Southern stream energy and a possible
frontal boundary atop the Gulf Coast/Florida could allow for rounds
of rain and storms there.


...Guidance/Predictability Assessment...

The early part of the medium range period (starting Wednesday)
shows reasonably good agreement on the large scale with the pattern
described above. Initial troughing will be quickly lifting out of
the north-central U.S. while a primary upper low is forecast just
offshore British Columbia and supports troughing atop the eastern
Pacific and Northwest. In the East, most upper troughing will be
exiting midweek but could leave some energy behind around the Gulf
Coast or so that would meander through much of the week south of
the agreeable ridge axis. The most uncertain part of the forecast
is how troughing in the West evolves. GFS runs from 00Z/06Z
maintained a closed low for longer as it slowly pushes into the
Northwest compared to the faster/open troughing of the ECMWF, CMC,
and most EC-based AI models by Thursday-Friday. The newer 12Z GFS
has jumped to an open trough, more like consensus, with a possible
shortwave farther in the Central Rockies or so on Saturday. The
evolution also depends on additional upstream energy dropping
through western Canada. For the most part the newer 12Z model suite
shows this energy being stronger as it moves into the Northwest
next weekend, and pushing the first shortwave east more quickly.
Will see if these trends continue.

The WPC forecast used a multi-model blend of deterministic
guidance early in the forecast period. As the period progressed,
increased the proportion of GEFS and EC ensemble means, reaching
half means for Days 6-7 amid increasing spread.


...Weather/Hazards Highlights...

A weak atmospheric river is forecast to push across the Pacific
Northwest into California Wednesday with a cold front ahead of the
upper trough. Rain totals generally under an inch or two do not
appear to cause hazardous conditions in the coastal mountain areas
that are accustomed to seeing multiple inches of rain. Rain could
continue in the West Coast states through Thursday with another
front. Rounds of precipitation will be likely across parts of the
Intermountain West/Rockies through multiple days this week, and the
higher elevations can expect snow. Moisture levels will be above
normal, but the rain seems unlikely to cause flooding concerns with
not much instability in place, limiting rain rates. Precipitation
chances should increase later week into next weekend across the
north-central U.S. once the frontal system emerges in the Plains.

After Imelda tracks east away from the Southeast U.S., some weak
energy aloft in the southern stream could stall south of the
northeastward oriented trough, which along with a frontal boundary
and sufficient moisture could lead to scattered showers and storms
across Florida and for the Southeast, especially along the Gulf
Coast. Through Wednesday and Thursday rain amounts and rates look
to stay below Marginal Risk ERO thresholds, but moisture and
instability look to increase by next weekend. Meanwhile most areas
under the upper trough stay dry through the latter half of the week
into the weekend, including the Southwest/southern Plains
extending into the Ohio Valley and the Northeast/Mid-Atlantic.

With upper ridging building overhead, warmer than seasonal average
temperatures are expected across the central U.S., most anomalous
for the Northern Plains to Upper Midwest. Highs of 10 to 20 degrees
above normal will be common in those areas through late week, with
highs of 80F reaching to the Canadian border by Wednesday. 90s are
likely to continue for early October into the Desert Southwest and
Texas. By next weekend, warmer than average temperatures could
shift a bit east and cover the Great Lakes region and Northeast.
Meanwhile, below normal temperatures especially for highs are
likely across the West due to upper troughing and rainy/cloudy
conditions.


Tate


Additional 3-7 Day Hazard information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation forecast (QPF), excessive rainfall
outlook (ERO), winter weather outlook (WWO) probabilities, heat
indices, and Key Messages can be accessed from:

https://www.wpc.ncep.noaa.gov/medr/5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/medr/5dayfcst_wbg_conus.gif
https://www.wpc.ncep.noaa.gov/5km_grids/5km_gridsbody.html
https://www.wpc.ncep.noaa.gov/qpf/day4-7.shtml
https://www.wpc.ncep.noaa.gov/#page=ero
https://www.wpc.ncep.noaa.gov/wwd/pwpf_d47/pwpf_medr.php?day=4
https://www.wpc.ncep.noaa.gov/heat_index.shtml
https://www.wpc.ncep.noaa.gov/#page=ovw