Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
352 AM EDT Sat Jun 08 2024

Valid 12Z Sat Jun 08 2024 - 12Z Mon Jun 10 2024

....There is an Enhanced Risk of severe thunderstorms over parts of the
Central High Plains on Saturday...

...There is a Moderate Risk of excessive rainfall over parts of the Middle
Mississippi Valley on Saturday and the Central/Southern High Plains on
Sunday...

...There are Heat Advisories over parts of western Texas...

A front over the Central Plains into the Central Rockies will move
eastward to off most of the Eastern Seaboard by Monday. The boundary will
aid in triggering showers and severe thunderstorms over parts of the
Central High Plains. Therefore, the SPC has issued an Enhanced Risk (level
3/5) of severe thunderstorms over parts of the Central High Plains through
Sunday morning. The hazards associated with these thunderstorms are
frequent lightning, severe thunderstorm wind gusts, hail, and a few
tornadoes. In addition, there is an added threat of severe thunderstorm
wind gusts of 65 knots or greater over parts of eastern Colorado and
western Kansas. Furthermore, there is also an added threat of hail, two
inches or greater, over parts of eastern Colorado.

Moreover, the showers and thunderstorms will create heavy rain over parts
of southern Missouri and the Central High Plain. Therefore, the WPC has
issued a Slight Risk (level 2/4) of excessive rainfall over parts of the
Middle Mississippi Valley through Sunday morning. The associated heavy
areas, roads, small streams, and low-lying areas the most vulnerable. rain
will create mainly localized areas of flash flooding, with urban areas,
roads, small streams, and low-lying areas the most vulnerable.

On Sunday, upper-level energy moving from the Southwest to the Southern
High Plains will create showers and strong to severe thunderstorms will
develop over parts of the Central/Southern High Plains. Therefore, the SPC
has issued a Marginal Risk (level 1/5) of severe thunderstorms over parts
of the Central/Southern High Plains from Sunday through Monday morning.
The hazards associated with these thunderstorms are frequent lightning,
severe thunderstorm wind gusts, hail, and a minimal threat of tornadoes.

The showers and thunderstorms will also cause heavy rain to develop over
parts of the Central/Southern High Plains. Therefore, the WPC has issued a
Slight Risk (level 2/4) of excessive rainfall over parts of the
Central/Southern High Plains from Sunday through Monday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, small streams, and low-lying areas the
most vulnerable.

Furthermore, an upper-level low over the Great Lakes/Northeast will help
produce rain over parts of the Great Lakes and the Northeast through
Monday. Another area of upper-level energy and a weakening front will help
create showers and thunderstorms over parts of Florida through Monday.

Furthermore, upper-level ridging over Texas helps spawn Heat Advisories
over parts of western Texas.


Ziegenfelder


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
308 AM EDT Sat Jun 8 2024

Valid 12Z Tue Jun 11 2024 - 12Z Sat Jun 15 2024

...Hot temperature shift from the West/Southwest to the Plains next
week as downstream heavy convective rainfall threats affect the
south-central states and from the Gulf of Mexico into Florida...


...Overview...

There is now better agreement in the guidance that an elongated
upper low over southern-eastern Canada will split early next week
with a trough moving through the Northeast into Tuesday and a
compact closed low getting left behind over south-central Canada
and the far northern U.S. tier. This energy should linger before
becoming absorbed by an additional shortwave energy approach from
western Canada. This progresses eastward mid-late next week with
troughing extending southward through the East.

Slow moving southern stream energy will keep unsettled conditions
and heavy rainfall potential particularly across the southern
Plains and lower Mississippi Valley early-mid next week, with an
inherent stronger threat signal for a multi-day wet period across
the Florida Peninsula along with building energies and convection
to monitor over a warmed Gulf of Mexico.

Upper ridging over the West/Southwest will gradually work into the
south-central U.S. with summer heat as a closed low works slowly
to the Southwest from the tropical East Pacific. Meanwhile, the
pattern will favor multiple but mostly dry Pacific upper trough and
cooling frontal intrusions across an unsettled Northwestern U.S..

...Guidance/Predictability Assessment...

Recent guidance forecast spread and run to run continuity issues
have drastically improved over the past few run cycles for at least
the first half of the upcoming medium range forecast period. This
bolsters forecast confidence back to near normal levels overall,
albeit still with standard and widespread warm season variances
with convective focus with local interaction and placement.

Accordingly, the WPC medium range product suite was primarily
derived from a composite blend of reasonably well clustered
guidance from the 18 UTC GFS and 12 UTC ECMWF/UKMET/Canadian models
valid for Tuesday into Thursday. The latest 00 UTC models remain
in line for this period. Growing forecast spread seems manageable
but sufficient to favor a switch to better compatible guidance from
the GEFS/ECMWF ensemble means at longer time frames to best depict
the more predictable pattern/weather features and keep continuity.

...Weather/Hazards Highlights...

A wavy front across the south-central Plains and vicinity will
combine with slowl moving upper energy to continue a threat for
heavy rainfall into Day 4/Tuesday from wettened Oklahoma to
northern Texas, with additional threat shifting into the lower
Mississippi Valley into Day 5/Wednesday. WPC Excessive Rainfall
Outlook (ERO) Marginal Threat areas are depicted for each day. A
multi-day period favorable for heavy rains will also develop
across the Florida Peninsula starting Tuesday as well above
moisture pools along/south of a the wavy/stalling front with some
aid from weak upper level impulses/energy. There is a lot of
uncertainty in the details and much of the state is in a drought.
Still, some threat for high rain rates exists, and its possible
much of the threat may manifest for more susceptable urbanized
areas. Day 4/5 WPC ERO Marginal Risk areas have been introduced to
include the central and southern Peninsula to account for the
uncertainty, with a looming threat into later next week as well
there and with any activity/moisture feed eminating over the Gulf.

An amplified mean upper ridge slated to slowly shift from the
West/Southwest to the south-central U.S. will continue to cause
much warmer than average temperatures. The highest temperature
anomalies of 10-20F above normal are forecast for the Great Basin,
warming a bit and expanding eastward as the week progresses into
the Rockies and Plains. Temperatures will also rise a few degrees
in the Desert Southwest to bring some temperatures back above 110F,
with heat risk threat levels mostly at moderate to major levels.
Heat should build again across south to south Texas as well, with
heat indices back up to around 110.

Schichtel


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

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
313 AM EDT Sat Jun 08 2024

Valid 00Z Sun Jun 09 2024 - 00Z Sun Jun 16 2024

A favored guidance composite shows generally lower than normal
moisture and rising mid-upper heights into next week. As the
pattern flips to ridging aloft, this will further promote drier
than normal conditions across the state. Weakened trades are
expected to gradually restrengthen later weekend and next week
back to moderate or breezy levels as more typical high pressure
develops and bridges to the north of the state. Moisture levels
may also finally tick up to normal or slightly above normal later
next week for some possible increase in showers, but coverage
still may be relatively limited under lingering upper ridging.

Schichtel

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
850 PM EDT Thu Jun 6 2024
Day 1
Valid 01Z Fri Jun 07 2024 - 12Z Fri Jun 07 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE NORTHEAST AS WELL AS THE TEXAS PANHANDLE AND PORTIONS OF
WESTERN OKLAHOMA...

...01Z update...

...Texas Panhandle Area...

A new Marginal Risk area was introduced with this update for the
Texas Panhandle and portions of western Oklahoma. A stationary
front draped across the area is providing a localized source of
lift for a pool of moisture running into the boundary from the
south. Nearly stationary storms have been developing along it as a
result...leaving a line of storms from western Oklahoma to far
eastern New Mexico.

Some of the CAMs guidance has captured the spirit of the storms,
with HREF guidance suggesting a 20% chance of 3 inches of rain
across the southern Texas Panhandle through 7am/12Z Friday. For
that reason, the Marginal Risk has been hoisted.

...Northeast...

A cold front sweeping across New England continues to provide the
forcing for an area of moderate rain with embedded heavier
convection. Most of the storms are moving quick enough that any
resultant flash flooding should be isolated. A separate line of
storms is just north of NYC, but these storms too are moving along
and only producing isolated rates to 3/4 inch per hour, so flash
flooding from these should also be very isolated, if it happens at
all.

Wegman

...16Z Update...

Little change was made to the inherited risk area as the prospects
for flooding remain similar to the previous forecast(s) as backed
by hi-res probability fields and associated numerical output. The
latest HREF signals maintain relative continuity with the area
across New England and over the southern Mid Atlantic as the
primary focal points for convective based flash flooding this
afternoon and evening. A small shift in the MRGL was necessitated
over portions of coastal southern New England due to a small, but
formidable axis of convergence along a warm front bisecting the
coasts of RI over into southeastern MA. Rainfall rates have reached
upwards of 2-2.5"/hr at times within the band of heavy rainfall.
While not overly convective in nature, anomalous low to mid-level
moisture with a zone of enhanced 925-850mb frontogenesis aligned
parallel to the coastal plain has provided a tongue of precip
totals breaching 1.5-2" over the aforementioned areas. The setup
will eventually vacate the area and end the threat, but current
radar presentations indicate at least another hour or two of
potential before the threat subsides.

This was the greatest change from the previous forecast.
Otherwise, general continuity with the threat across the Mid
Atlantic evolving from convection along and just ahead of an
approaching cold front. Heavy rain over northern New England is due
to primed upper forcing within a broad axis of diffluence present
downstream of a potent shortwave trough swinging through the Great
Lakes and adjacent Ontario Province.

Kleebauer


...Previous Discussion...

...Mid Atlantic to Northeast...

A slow moving cold front, currently analyzed across portions of the
Ohio Valley and Appalachians, will cross through the Mid Atlantic
and Northeast today into tonight. Meanwhile, a warm front will
continue lifting northward through the Northeast this morning
before stalling or slowing across southern New England this
afternoon. The airmass will be quite moist, with the latest
guidance pointing toward PWs well above normal (exceeding 95th
percentile) with values over 1.75" from the Mid-Atlantic into
southern New England and near 1.5" across northern NY and portions
of VT/NH. This morning there should be an initial round of locally
heavy downpours with the warm front passage across southern NY and
southern New England, which could bring localized flooding concerns
with rain rates exceeding 1"/hr. A second round is then expected
for the afternoon/evening with the approaching cold front but also
could train/repeat with the warm front stalling nearby. Convective
initiation is likely between 16-18Z across western NY and PA with a
line of showers and thunderstorms moving east/northeast through
the remainder of the day.

The latest HREF probabilities for 24-hr totals of at least 2" are
spotty but show some signal exceeding 40-50 percent in locations
form eastern/northern NY and southern New England). Probabilities
for hourly totals of 1-2" are slight (under 30 percent).

Further south into the Mid-Atlantic, higher moisture ahead of the
cold front and sufficiently warm temperatures will support a line
or two of stronger showers and thunderstorms during the
afternoon/evening hours. Some of these will be capable of producing
heavy downpours, particularly from the I-95 corridor from
Baltimore to Richmond and eastward including southeast VA where the
2" HREF neighborhood probabilities are locally higher near 50
percent.

Taylor

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
404 AM EDT Sat Jun 8 2024
Day 1
Valid 12Z Sat Jun 08 2024 - 12Z Sun Jun 09 2024

...THERE IS A MODERATE RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF SOUTHERN MISSOURI...

...Eastern Kansas, Missouri, and Mid Mississippi Valley...

A Moderate Risk (Level 3 of 4) was introduced for this forecast
cycle for portions of southern Missouri where rounds of
thunderstorms through early Sunday are likely to produce several
inches of rainfall in a short period. Scattered to numerous
instances of flash flooding are likely, with localized significant
flooding possible.

As of early this morning, a slow-moving MCS is advancing through
far eastern Kansas and western Missouri and is expected to weaken
some as it moves across Missouri by the beginning of the forecast
period at 12Z. It will however likely lay out an outflow boundary
west to east across far southeast Kansas through southern Missouri
which will become the main focus for additional thunderstorm
development later in the period.

By late afternoon, the increasing moisture impinging on this
boundary (PWs 2"+, 2-3 std above normal) and modest amounts of
instability (MUCAPE 2000-3000 J/kg) is likely to ignite another
round of deep convection. This activity is likely then to
train/repeat west to east as the flow becomes increasingly parallel
to the expected storm motions. This will favor some intense rain
rates and high totals due to the combination of the favorable
ingredients and training flow pattern. Several repeating rounds
are possible, particularly over southwest to south-central MO. The
HREF probabilities have continued to trend higher this cycle, the
24-hr 5" probabilities are exceeding 50 percent across southwest
MO and there are slight signals (10-15 percent) for hourly totals
in excess of 3" for several hours later this afternoon/evening.

The primary forecast uncertainty is placement, with some
north/south differences between the various hi-res models still at
this forecast lead time and is likely tied to how this morning's
convection plays out and where the effective boundary ends up
settling. The consensus is for somewhere across far southeast KS
through Missouri, though some determinsitic solutions are a bit to
the north.


...Eastern Colorado to Kansas...

The combination of robust heating, a modest amount of moisture, and
an approaching shortwave trough will ignite a few rounds of intense
thunderstorms later today initially over Colorado before evolving
into an organized complex over western Kansas. Intense rain rates
and some localized/slight threat of training could result in
scattered instances of flash flooding.

Convection initiation over the Front Range will be driven by the
sufficient heating and shortwave trough moving through, and
gradually the storms will move into a more moist environment (PWs
getting closer to 1-1.25") that will help them grow upscale into
an MCS. The latest HREF probabilities are moderate/high for 1"
hourly totals (above 60 percent) across northern/northeast CO and
even reach 20-25 percent for 2" hourly totals before increasing to
above 50 percent across western Kansas when the larger MCS is
likely to set up. For 24-hr rainfall totals, the HREF points to
western KS for the greatest threat of at least 3 inches (above 40
percent) where the Slight Risk skews toward the higher end of the
probability range (25-40%). By evening, the MCS should be rolling
through Kansas at a faster clip but still will have enough
environmental ingredient support to maintain the Slight for intense
rain rates above 2"/hr at times and isolated/scattered instances
of flash flooding.

Taylor

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
404 AM EDT Sat Jun 8 2024
Day 2
Valid 12Z Sun Jun 09 2024 - 12Z Mon Jun 10 2024

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
SOUTHEAST COLORADO, NORTHEAST NEW MEXICO, AND THE TEXAS
PANHANDLE...

...Southern Plains to Central High Plains...

Scattered to numerous thunderstorms are expected to develop across
the region during the period, with a Slight Risk (Level 2 of 4) of
excessive rainfall and flash flooding. A frontal boundary is
forecast to be draped across the region, from eastern New Mexico
through the Texas Panhandle. With that, a very anomalous pool of
moisture will bank up against the terrain with PWs forecast to be
above 1.5", which is 2-3 std above normal. A shortwave trough
coming out of northwest Mexico is forecast to reach the region by
the period, and this will help drive the more widespread
convection, particularly over eastern NM. The latest model
guidance continues to highlight potential for several inches (1-3")
over eastern NM into parts of the TX Panhandle and with that and
the environmental ingredients for more intense rain rates, the
Slight Risk was only adjusted minimally from the previous forecast.

...Mid Mississppi Valley...
The frontal boundary draped across the region along with favorable
amounts of moisture will support isolated to scattered
thunderstorms, with storms likely ongoing at the start of the
period across Missouri that move eastward and weaken through the
day. By later in the period, loosely organized convection is likely
but without any strong focus, the Marginal Risk was maintained for
potential of localized 1-1.5" totals.

Taylor

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
404 AM EDT Sat Jun 8 2024
Day 3
Valid 12Z Mon Jun 10 2024 - 12Z Tue Jun 11 2024

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF NORTHERN PLAINS AND SOUTHERN HIGH PLAINS INTO THE SOUTHERN
PLAINS...

...Northern Plains...
A shortwave trough and a cold front will move through the region.
Ahead of this feature, a ribbon of higher moisture will be
advancing northward and will be characterized by PWs between
1-1.5". Along with MLCAPE values above 1000 J/kg, there is good
overlap of the moisture, lift, and instability to support rounds of
thunderstorms by afternoon/evening. With cell mergers and boundary
interactions, an isolated flash flood threat can't be ruled out
with potential for isolated 1-2"/hr rain rates that could cause
flash flooding, so a Marginal Risk was introduced.

...Southern High Plains to Southern Plains...
A forming closed low straddling NM/TX border will slowly settle
east/southeast through the period and across the entire region
there should be fairly high moisture remaining in place (PWs
1.25-1.75") that will support scattered thundestorms. The focus
will be on the Texas Panhandle southward into west-central Texas
where totals may approach 1-3".



Taylor

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
308 AM EDT Sat Jun 8 2024


A wavy front across the south-central Plains and vicinity will
combine with slowl moving upper energy to continue a threat for
heavy rainfall into Day 4/Tuesday from wettened Oklahoma to
northern Texas, with additional threat shifting into the lower
Mississippi Valley into Day 5/Wednesday. WPC Excessive Rainfall
Outlook (ERO) Marginal Threat areas are depicted for each day. A
multi-day period favorable for heavy rains will also develop
across the Florida Peninsula starting Tuesday as well above
moisture pools along/south of a the wavy/stalling front with some
aid from weak upper level impulses/energy. There is a lot of
uncertainty in the details and much of the state is in a drought.
Still, some threat for high rain rates exists, and its possible
much of the threat may manifest for more susceptable urbanized
areas. Day 4/5 WPC ERO Marginal Risk areas have been introduced to
include the central and southern Peninsula to account for the
uncertainty, with a looming threat into later next week as well
there and with any activity/moisture feed eminating over the Gulf.

An amplified mean upper ridge slated to slowly shift from the
West/Southwest to the south-central U.S. will continue to cause
much warmer than average temperatures. The highest temperature
anomalies of 10-20F above normal are forecast for the Great Basin,
warming a bit and expanding eastward as the week progresses into
the Rockies and Plains. Temperatures will also rise a few degrees
in the Desert Southwest to bring some temperatures back above 110F,
with heat risk threat levels mostly at moderate to major levels.
Heat should build again across south to south Texas as well, with
heat indices back up to around 110.

Schichtel

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
308 AM EDT Sat Jun 8 2024


A wavy front across the south-central Plains and vicinity will
combine with slowl moving upper energy to continue a threat for
heavy rainfall into Day 4/Tuesday from wettened Oklahoma to
northern Texas, with additional threat shifting into the lower
Mississippi Valley into Day 5/Wednesday. WPC Excessive Rainfall
Outlook (ERO) Marginal Threat areas are depicted for each day. A
multi-day period favorable for heavy rains will also develop
across the Florida Peninsula starting Tuesday as well above
moisture pools along/south of a the wavy/stalling front with some
aid from weak upper level impulses/energy. There is a lot of
uncertainty in the details and much of the state is in a drought.
Still, some threat for high rain rates exists, and its possible
much of the threat may manifest for more susceptable urbanized
areas. Day 4/5 WPC ERO Marginal Risk areas have been introduced to
include the central and southern Peninsula to account for the
uncertainty, with a looming threat into later next week as well
there and with any activity/moisture feed eminating over the Gulf.

An amplified mean upper ridge slated to slowly shift from the
West/Southwest to the south-central U.S. will continue to cause
much warmer than average temperatures. The highest temperature
anomalies of 10-20F above normal are forecast for the Great Basin,
warming a bit and expanding eastward as the week progresses into
the Rockies and Plains. Temperatures will also rise a few degrees
in the Desert Southwest to bring some temperatures back above 110F,
with heat risk threat levels mostly at moderate to major levels.
Heat should build again across south to south Texas as well, with
heat indices back up to around 110.

Schichtel

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
1031 AM EDT Mon May 13 2024

Valid 00Z Tue May 14 2024 - 00Z Fri May 17 2024

...WPC Winter Weather Desk no longer routinely staffed this
summer...

Pending any significant winter weather, the WPC Winter Weather Desk
will not be staffed this summer. The desk will resume continuous
staffing starting in late September 2024.

Most of the winter products from WPC will continue to be produced,
including the Winter Storm Severity Index (WSSI), Probabilistic
Winter Storm Severity Index (WSSI-P), and the Probabilistic Winter
Precipitation Forecasts (PWPF).

WPC

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
308 AM EDT Sat Jun 8 2024

Valid 12Z Tue Jun 11 2024 - 12Z Sat Jun 15 2024

...Hot temperature shift from the West/Southwest to the Plains next
week as downstream heavy convective rainfall threats affect the
south-central states and from the Gulf of Mexico into Florida...


...Overview...

There is now better agreement in the guidance that an elongated
upper low over southern-eastern Canada will split early next week
with a trough moving through the Northeast into Tuesday and a
compact closed low getting left behind over south-central Canada
and the far northern U.S. tier. This energy should linger before
becoming absorbed by an additional shortwave energy approach from
western Canada. This progresses eastward mid-late next week with
troughing extending southward through the East.

Slow moving southern stream energy will keep unsettled conditions
and heavy rainfall potential particularly across the southern
Plains and lower Mississippi Valley early-mid next week, with an
inherent stronger threat signal for a multi-day wet period across
the Florida Peninsula along with building energies and convection
to monitor over a warmed Gulf of Mexico.

Upper ridging over the West/Southwest will gradually work into the
south-central U.S. with summer heat as a closed low works slowly
to the Southwest from the tropical East Pacific. Meanwhile, the
pattern will favor multiple but mostly dry Pacific upper trough and
cooling frontal intrusions across an unsettled Northwestern U.S..

...Guidance/Predictability Assessment...

Recent guidance forecast spread and run to run continuity issues
have drastically improved over the past few run cycles for at least
the first half of the upcoming medium range forecast period. This
bolsters forecast confidence back to near normal levels overall,
albeit still with standard and widespread warm season variances
with convective focus with local interaction and placement.

Accordingly, the WPC medium range product suite was primarily
derived from a composite blend of reasonably well clustered
guidance from the 18 UTC GFS and 12 UTC ECMWF/UKMET/Canadian models
valid for Tuesday into Thursday. The latest 00 UTC models remain
in line for this period. Growing forecast spread seems manageable
but sufficient to favor a switch to better compatible guidance from
the GEFS/ECMWF ensemble means at longer time frames to best depict
the more predictable pattern/weather features and keep continuity.

...Weather/Hazards Highlights...

A wavy front across the south-central Plains and vicinity will
combine with slowl moving upper energy to continue a threat for
heavy rainfall into Day 4/Tuesday from wettened Oklahoma to
northern Texas, with additional threat shifting into the lower
Mississippi Valley into Day 5/Wednesday. WPC Excessive Rainfall
Outlook (ERO) Marginal Threat areas are depicted for each day. A
multi-day period favorable for heavy rains will also develop
across the Florida Peninsula starting Tuesday as well above
moisture pools along/south of a the wavy/stalling front with some
aid from weak upper level impulses/energy. There is a lot of
uncertainty in the details and much of the state is in a drought.
Still, some threat for high rain rates exists, and its possible
much of the threat may manifest for more susceptable urbanized
areas. Day 4/5 WPC ERO Marginal Risk areas have been introduced to
include the central and southern Peninsula to account for the
uncertainty, with a looming threat into later next week as well
there and with any activity/moisture feed eminating over the Gulf.

An amplified mean upper ridge slated to slowly shift from the
West/Southwest to the south-central U.S. will continue to cause
much warmer than average temperatures. The highest temperature
anomalies of 10-20F above normal are forecast for the Great Basin,
warming a bit and expanding eastward as the week progresses into
the Rockies and Plains. Temperatures will also rise a few degrees
in the Desert Southwest to bring some temperatures back above 110F,
with heat risk threat levels mostly at moderate to major levels.
Heat should build again across south to south Texas as well, with
heat indices back up to around 110.

Schichtel


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