Weather Prediction Center

National Oceanic and Atmospheric Administration

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
404 PM EDT Fri May 27 2022

Valid 00Z Sat May 28 2022 - 00Z Mon May 30 2022

...There is a Slight Risk of excessive rainfall over parts of the
Mid-Atlantic through Saturday morning...

...There is a Slight Risk of severe storms over parts of the
Mid-Atlantic/Southeast and the Northern High Plains through Saturday
morning...

...There is a Slight Risk of severe storms over parts of the
Northern/Central Plains from Saturday to Sunday morning...

...There is a Critical Risk of fire weather over parts of the
Southwest/Southern Rockies...

On Friday night, a front extending from the Lower Great Lakes to the
Southeast/Central Gulf Coast will slowly move off the Northeast/northern
Mid-Atlantic Coast by Sunday morning. Showers and thunderstorms will
develop along and ahead of the boundary through Saturday. In addition, the
front and moisture pooling along the boundary will destabilize the
atmosphere. Therefore, the SPC has issued a Slight Risk of severe
thunderstorms over parts of the Mid-Atlantic/Southeast through Saturday
morning. The hazards associated with these thunderstorms are frequent
lightning, severe thunderstorm wind gusts, hail, and a few tornadoes.

In addition, showers and thunderstorms develop along the boundary from the
Northeast to the Southeast. Therefore, the WPC has issued a Slight Risk of
excessive rainfall over the Mid-Atlantic through Saturday morning. The
associated heavy rain will create mainly localized areas of flash
flooding, with urban areas, roads, and small streams the most vulnerable.
On Saturday, the front continues to advance eastward. As a result, showers
and thunderstorms will develop over the Northeast, the Mid-Atlantic Coast,
and the Florida Peninsula, coming to an end overnight Saturday.

Meanwhile, there is a complicated series of fronts moving across the
Northern High Plains to the Northern Plains by Saturday morning. The
boundaries will aid in producing light rain over parts of the Pacific
Northwest and moving into the Northern Intermountain Region by Saturday
morning. In addition, the front will destabilize the atmosphere over the
Northern High Plains. Therefore, the SPC has issued a Slight Risk of
severe thunderstorms over parts of the Northern High Plains through
Saturday morning. The hazards associated with these thunderstorms are
frequent lightning, severe thunderstorm wind gusts, hail, and a minimal
threat of tornadoes.

The severe thunderstorm threat continues on Saturday. Therefore, the SPC
has issued a Slight Risk of severe thunderstorms over parts of the
Northern/Central Plains from Saturday through Sunday morning. The hazards
associated with these thunderstorms are frequent lightning, severe
thunderstorm wind gusts, hail, and a minimal threat of tornadoes.

In the meantime, a third front moves onshore over the Pacific Northwest
and advances to the Northern Plains by Sunday. Light rain will return to
the Pacific Northwest by late Saturday morning and expand into the
Northern Intermountain Region by late Saturday afternoon. Overnight
Saturday, the snow levels will lower over parts of the higher elevations.
Therefore, the highest elevations of the Cascades and Northern Rockies
will get light wet snow. As the front moves out of the Rockies onto the
Plains, The threat of severe thunderstorms returns to the Northern/Central
Plains on Sunday.

Lastly, a Critical Risk of fire weather returns to the Southwest and the
Southern Rockies on Saturday. The threat is due to strong gusty winds, dry
fuels, and low humidity.

Ziegenfelder

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

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
432 PM EDT Fri May 27 2022

Valid 12Z Mon May 30 2022 - 12Z Fri Jun 03 2022

...Potential for heavy precipitation next week from the northern
Rockies to Upper Midwest and then southward through the Plains...

...Weather Pattern Overview...

The medium range period begins Monday with a rather amplified
upper level pattern for late May, consisting of an anomalously
deep trough with embedded low in the West and ridging over much of
the East (though suppressed in the Northeast by an eastern Canada
upper low). This configuration will allow for potentially heavy
precipitation to spread from the northern Rockies into the
northern Plains and Upper Midwest. Higher elevation snow is
possible in the Rockies while heavy rain and severe weather are
threats in the Plains to Midwest along with warmer than normal
temperatures. As next week progresses, the mean flow aloft should
flatten quickly as the main western upper low lifts into
south-central Canada and consolidates with separate central Canada
energy to yield a fairly deep upper low. The highest precipitation
chances should shift into the central/southern Plains and across
the East along and ahead of the cold front that pushes eastward
from the Plains. Toward the end of next week an upper trough may
bring a front and some associated moisture into the Northwest.


...Model Guidance Evaluation/Preferences...

Latest guidance through the 00Z/06Z cycles has generally followed
through on recent trends toward faster ejection of the main
western U.S. upper low through the northern tier and then stronger
interaction with central Canada energy to yield a rather deep
upper low and vigorous surface system just southwest of Hudson Bay
by midweek. The deeper evolution ultimately leads to somewhat
faster progression of the front that begins to push eastward from
the Plains. Even with the faster trend, other 12Z models suggest
the new GFS may be too fast with the northern U.S./southern Canada
system by early Tuesday. Details of a separate weaker northwestern
U.S. upper low shearing out as the mean pattern rapidly flattens
continue to be somewhat ambiguous, and will affect frontal
wave/rainfall specifics to the east of the Rockies. Outside of the
UKMET, new 12Z models have trended stronger with this feature
through Tuesday-Wednesday. Meanwhile there is decent agreement in
principle that energy underneath the eastern U.S. upper ridge may
try to consolidate into a closed low somewhere near the Southeast
coast/Florida/northern Bahamas by midweek. However by day 7 Friday
recent GFS/GEFS mean runs have developed a deeper and more
expansive trough covering the Southeast U.S. and eastern Gulf
relative to most other guidance. The 12Z GEFS mean trended a bit
weaker with its day 7 upper trough though. On the northern side
of the eastern ridge, guidance is gradually consolidating toward
an episode of fairly strong cyclonic flow around a far eastern
Canada upper low. This leads to increasing potential for the
associated cold front reaching New England early in the week to
push as far south as the northern Mid-Atlantic as a backdoor front
before eventually returning north as a warm front. Consensus is
reasonable for upper ridging to retrograde from the
East/Mississippi Valley and then settle over the southern
Plains/northern Mexico, connecting with the ridge that builds over
the Interior West/Rockies. For the upper trough approaching the
West Coast late in the week, GFS runs show a little more
southeastward amplitude versus the majority at times but
ultimately model/mean differences are within typical error ranges
for forecasts that far out in time. Guidance comparisons led to
using a 00Z/06Z model blend early in the period followed by
transitioning to a model/mean mix, with slightly more weight to
the 00Z ECMWF/ECMWF mean versus the 06Z GFS/GEFS mean (with
lingering 00Z CMC input) due to aforementioned issues over/near
the Southeast.


...Sensible Weather/Threat Highlights...

Early next week, the upper low emerging from the West along with
areas of low level upslope flow should combine to generate
moderate to heavy precipitation over the northern Rockies and High
Plains. Higher elevations of the northern Rockies particularly in
southern Montana to northern Wyoming could see significant late
season snow as the anomalously deep system leads to colder than
average conditions. Farther east, rain and thunderstorms are
threats across the northern Plains into the Midwest along a wavy
front that should initially be slow to move. Along this front, a
fairly strong surface system developing over the northern tier
into southern Canada during the first half of the week may help to
focus rainfall as well. Severe weather and heavy rain are both
possibilities with this convection. As the upper pattern flattens,
lower amplitude troughing will likely move slowly eastward across
northern parts of the central and eastern U.S. and push a cold
front ahead of it into the East back into the central/southern
Plains. This front will serve as a focus for convection as it
presses east across the Ohio Valley to the Eastern Seaboard and
south across the Plains and Mississippi Valley for the latter half
of the workweek. Some moderate to heavy rainfall is possible
especially across parts of the central U.S. but still with lower
than average confidence for the areal details and amounts.
Elsewhere, Florida can expect some scattered diurnally favored
convection, aided by energy aloft to the south of the eastern U.S.
upper ridge. This convection may become more widespread by late
week. Also the Northeast may see mostly light rainfall along a
backdoor front for the first half of the workweek before the
better focus for rainfall around Thursday just ahead of the main
cold front. A front expected to push into the Northwest late in
the week may bring areas of light rainfall.

The eastern U.S./Mississippi Valley upper ridge will promote above
average temperatures by 10-20F from the Plains to the Midwest/Ohio
Valley and the Northeast/Mid-Atlantic Monday-Wednesday, with some
daily record high maximum and minimum temperatures possible. The
backdoor front reaching New England and possibly as far south as
the northern Mid-Atlantic would bring a cooler trend to these
areas though. Meanwhile upper troughing will bring very cool
temperatures to areas from the Intermountain West through northern
Plains early in the week with highs forecast to be 10-20F or below
normal. The flattening pattern aloft will push the initial Plains
cold front eastward while leading to a moderating trend for below
normal temperatures over the central U.S., with mostly
single-digit negative anomalies by Thursday-Friday. The East will
see shrinking coverage of warm temperatures after Wednesday. The
West Coast and into the Great Basin could flip back to warmer than
normal temperatures by around 5-10F Wednesday and beyond, followed
by modest cooler trend on Friday along the immediate West Coast
with the arrival of a Pacific front.

Rausch/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

Hazards:
- Heavy precipitation across portions of the Northern
Plains/Rockies, Mon, May 30.
- Heavy rain across portions of the Central Plains, the Middle
Mississippi Valley, and the Southern
Plains, Tue-Wed, May 31-Jun 1.
- Heavy rain across portions of the Upper Mississippi Valley, and
the Northern Plains, Mon, May 30.
- Severe weather across portions of the Great Plains, and the
Middle/Upper Mississippi Valley, Mon,
May 30.
- Flooding occurring or imminent across portions of the
Central/Northern Plains, and the Upper
Mississippi Valley.
- Flooding likely across portions of the Central Plains.
- High winds across portions of the Central Plains/Rockies/Great
Basin, the Southern
Rockies/Plains, and the Southwest, Mon, May 30.
- Enhanced wildfire risk across portions of the Southern Rockies,
the Central/Southern Plains, and
the Southwest, Mon, May 30.

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, experimental excessive rainfall
outlook, winter weather outlook probabilities and heat indices are
at:

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

Hawaii Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
336 AM EDT Fri May 27 2022

Valid 00Z Sat May 28 2022 - 00Z Sat Jun 04 2022

Relatively dry and quiet weather is likely over Hawaii for the
next week or so, as an upper-level high to the east of the state
through this weekend gradually drifts westward atop Hawaii next
week. At the surface, high pressure is in place to the northeast
of the state, leading to easterly trade winds at moderate to
locally breezy levels Friday. This high is forecast to drift
farther northeast away from Hawaii this weekend into early next
week and weaken the trades. This will allow for afternoon sea
breezes and nighttime land breezes to set up, along with some
potential for showers even over interior and leeward areas. These
are expected to be only scattered and light given normal to below
normal moisture levels for the most part, though Kauai may see a
period of above normal moisture around Sunday coincident with a
possible weak upper trough. As surface high pressure redevelops
north of the islands next week, more moderate trade winds should
redevelop, making windward and mountain areas more of a focus for
limited showers that occur in the dry pattern.

Tate

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1140 AM EDT Fri May 27 2022

Day 1
Valid 16Z Fri May 27 2022 - 12Z Sat May 28 2022

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL IN THE EASTERN
UNITED STATES...

16Z Update: Initial line of showers/storms moving through
Mid-Atlantic this morning will continue tracking north/northeast.
Higher PWs and unidirectional flow supports some efficient rain
producing storms with the potential for training and
isolated/scattered instances of flash flooding. Redevelopment to
the west along the cold front later this afternoon/evening is
likely and could bring an additional round of storms across a
similar area, so the Slight Risk was maintained for this update.
Slow moving convection along stationary boundary and near/north of
the closed low could result in pockets of higher rain totals. The
slow storm motions may lead to an isolated flash flood risk and
MPD 260 in effect through 21Z goes into more detail for that
particular risk.

Taylor

---previous discussion---
Much of the eastern U.S. will see areas of showers and
thunderstorms today ahead of the eastward moving large scale
trough and embedded well defined mid/upper level low. A Slight
risk was maintained for portions of the Mid Atlantic from northern
NC into eastern PA. From a flash flood areal coverage perspective
this is probably on the lower end of the Slight risk range
(15-40%), however localized swaths of flash flooding do appear
probable. The environment will be conducive to efficient rainfall,
with PWs forecast above the climatological 90th percentile, a deep
warm layer, and high deep layer RH. Thus we should be able to
realize some pretty heavy rainfall rates with convection across
this area...main question will be the duration of this rainfall.
Convection is expected to move progressively off to the
east...however mainly unidirectional flow does support some linear
south/north training segments through the day. There is also the
likelihood of multiple convective rounds over some locations, with
strong synoptic forcing lagging the initial convective line and
supporting additional development in its wake. The combination of
efficient rainfall, small scale training segments, and multiple
convective rounds...should support a localized to scattered flash
flood risk today within the Slight risk region. The risk is
greatest across urban areas and/or locations where any training
segments materialize (resulting in swaths of 2-3" of rainfall).

The potential is there for localized higher rainfall totals south
of the Slight risk area from southern NC into the FL Panhandle.
Better instability supports pockets of 3-5" of rainfall
here...although amounts of this magnitude should stay pretty
localized in nature. That combined with the higher FFG over this
region suggests more of a localized flash flood risk which is
covered by a Marginal risk.

A Marginal risk extends westward across portions of the OH valley
into the southern Great Lakes. Slow moving convection near and
north of the closed mid level low should support localized areas
of heavy rainfall across this corridor (similar to what occurred
north of the low Thursday). Isolated flash flooding is possible.

Training convection near a stationary front is possible this
afternoon/evening across portions of northern NY into northern New
England. This signal is strongest over portions of northern ME
within the ~22z-03z time frame tonight. The 00z HREF indicates
moderate probabilities of 1" an hour rates...as instability should
be just enough to take advantage of near record PWs for late May
to support these rates. Three hour FFG over the area is ~1.5" and
the 00z HREF indicates about a 40% chance of exceeding this total.
However given the average to below average soil moisture and
streamflows, and rainfall rates probably not exceeding 1" in an
hour by all that much, the resultant flash flood risk is probably
still pretty localized in nature. Thus will maintain a Marginal
risk over this region.

Chenard

Day 1 threat area: www.wpc.ncep.noaa.gov/qpf/94epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
348 PM EDT Fri May 27 2022

Day 2
Valid 12Z Sat May 28 2022 - 12Z Sun May 29 2022

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS NEW
ENGLAND...SOUTH FLORIDA...AND PORTIONS OF THE NORTHERN PLAINS...

...New England...
Isolated instances of flash flooding will be possible Saturday
ahead of a slow moving cold front. Modest amounts of moisture and
instability present during peak heating should destabilize the
airmass enough for loosely organized convection from eastern NY
through much of New England. HREF probabilities for 1"/hr approach
moderate levels and show some 2-5 yr ARI exceedance probabilities.
Below normal rainfall departures over the last week and dry soils
should keep flash flood risk localized/isolated, but any slow
moving or repeating rounds over sensitive and urban areas could
lead to a few instances of flash flooding.

...South Florida...
A washed out frontal boundary draped across the Peninsula
interacting with daytime heating sea breeze convection could give
way to a few clusters of strong thunderstorms capable of producing
intense rain rates over the highly urbanized south Florida
corridor. HREF probabilities are slight/moderate for 2-3"/hr
totals and merging boundary interactions may lead to a few rounds
of storms capable of producing flash flooding.

...Northern Plains...
Large scale troughing over the western U.S. will lead to several
impulses pushing out into the Northern Plains Saturday. The signal
for an axis of 1-2" from eastern MT to western ND in the
afternoon/evening hours still looks good and with the potential
for hourly totals up to 1" at times, decided to introduce a
Marginal Risk. However, the lack of deeper instability and dry
soils could keep flash flood risk fairly isolated. Further south
across South Dakota, better ingredients will be in place for
stronger and more organized storms, but progressive nature and
likely sparse coverage look to keep any flash flood risk under 5
percent.


Chenard/Taylor

Day 2 threat area: www.wpc.ncep.noaa.gov/qpf/98epoints.txt

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
349 PM EDT Fri May 27 2022

Day 3
Valid 12Z Sun May 29 2022 - 12Z Mon May 30 2022

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE CENTRAL/NORTHERN PLAINS INTO THE UPPER MISSISSIPPI VALLEY...

Deep troughing ejecting out of the Northern Rockies into the
Northern Plains will lead to a broad area of enhanced lift across
the eastern Dakotas and Upper Midwest Sunday/Sunday night.
Embedded shortwave impulses within the flow will lead to multiple
convective clusters supporting heavy rainfall. Ingredients
continue to look favorable/conducive for heavy rainfall with an
environment characterized by anomalously high PWs, sufficient
instability, and strong low level moisture transport. Only minor
changes were made to the Marginal Risk for this update and as the
event draws near, could see an upgrade to a Slight somewhere but
confidence in those details remain low at this point.


Chenard/Taylor

Day 3 threat area: www.wpc.ncep.noaa.gov/qpf/99epoints.txt

Probabilistic Heavy Snow and Icing Discussion
NWS Weather Prediction Center College Park MD
309 PM EDT Tue May 10 2022

Valid 00Z Wed May 11 2022 - 00Z Sat May 14 2022

***Regularly scheduled Heavy Snow/Ice Discussions have ended for
the 2021-2022 season from WPC***

--This discussion may be updated over the summer months should the
forecast warrant--

~~Discussions will resume on or around October 1, 2022~~

Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
432 PM EDT Fri May 27 2022

Valid 12Z Mon May 30 2022 - 12Z Fri Jun 03 2022

...Potential for heavy precipitation next week from the northern
Rockies to Upper Midwest and then southward through the Plains...

...Weather Pattern Overview...

The medium range period begins Monday with a rather amplified
upper level pattern for late May, consisting of an anomalously
deep trough with embedded low in the West and ridging over much of
the East (though suppressed in the Northeast by an eastern Canada
upper low). This configuration will allow for potentially heavy
precipitation to spread from the northern Rockies into the
northern Plains and Upper Midwest. Higher elevation snow is
possible in the Rockies while heavy rain and severe weather are
threats in the Plains to Midwest along with warmer than normal
temperatures. As next week progresses, the mean flow aloft should
flatten quickly as the main western upper low lifts into
south-central Canada and consolidates with separate central Canada
energy to yield a fairly deep upper low. The highest precipitation
chances should shift into the central/southern Plains and across
the East along and ahead of the cold front that pushes eastward
from the Plains. Toward the end of next week an upper trough may
bring a front and some associated moisture into the Northwest.


...Model Guidance Evaluation/Preferences...

Latest guidance through the 00Z/06Z cycles has generally followed
through on recent trends toward faster ejection of the main
western U.S. upper low through the northern tier and then stronger
interaction with central Canada energy to yield a rather deep
upper low and vigorous surface system just southwest of Hudson Bay
by midweek. The deeper evolution ultimately leads to somewhat
faster progression of the front that begins to push eastward from
the Plains. Even with the faster trend, other 12Z models suggest
the new GFS may be too fast with the northern U.S./southern Canada
system by early Tuesday. Details of a separate weaker northwestern
U.S. upper low shearing out as the mean pattern rapidly flattens
continue to be somewhat ambiguous, and will affect frontal
wave/rainfall specifics to the east of the Rockies. Outside of the
UKMET, new 12Z models have trended stronger with this feature
through Tuesday-Wednesday. Meanwhile there is decent agreement in
principle that energy underneath the eastern U.S. upper ridge may
try to consolidate into a closed low somewhere near the Southeast
coast/Florida/northern Bahamas by midweek. However by day 7 Friday
recent GFS/GEFS mean runs have developed a deeper and more
expansive trough covering the Southeast U.S. and eastern Gulf
relative to most other guidance. The 12Z GEFS mean trended a bit
weaker with its day 7 upper trough though. On the northern side
of the eastern ridge, guidance is gradually consolidating toward
an episode of fairly strong cyclonic flow around a far eastern
Canada upper low. This leads to increasing potential for the
associated cold front reaching New England early in the week to
push as far south as the northern Mid-Atlantic as a backdoor front
before eventually returning north as a warm front. Consensus is
reasonable for upper ridging to retrograde from the
East/Mississippi Valley and then settle over the southern
Plains/northern Mexico, connecting with the ridge that builds over
the Interior West/Rockies. For the upper trough approaching the
West Coast late in the week, GFS runs show a little more
southeastward amplitude versus the majority at times but
ultimately model/mean differences are within typical error ranges
for forecasts that far out in time. Guidance comparisons led to
using a 00Z/06Z model blend early in the period followed by
transitioning to a model/mean mix, with slightly more weight to
the 00Z ECMWF/ECMWF mean versus the 06Z GFS/GEFS mean (with
lingering 00Z CMC input) due to aforementioned issues over/near
the Southeast.


...Sensible Weather/Threat Highlights...

Early next week, the upper low emerging from the West along with
areas of low level upslope flow should combine to generate
moderate to heavy precipitation over the northern Rockies and High
Plains. Higher elevations of the northern Rockies particularly in
southern Montana to northern Wyoming could see significant late
season snow as the anomalously deep system leads to colder than
average conditions. Farther east, rain and thunderstorms are
threats across the northern Plains into the Midwest along a wavy
front that should initially be slow to move. Along this front, a
fairly strong surface system developing over the northern tier
into southern Canada during the first half of the week may help to
focus rainfall as well. Severe weather and heavy rain are both
possibilities with this convection. As the upper pattern flattens,
lower amplitude troughing will likely move slowly eastward across
northern parts of the central and eastern U.S. and push a cold
front ahead of it into the East back into the central/southern
Plains. This front will serve as a focus for convection as it
presses east across the Ohio Valley to the Eastern Seaboard and
south across the Plains and Mississippi Valley for the latter half
of the workweek. Some moderate to heavy rainfall is possible
especially across parts of the central U.S. but still with lower
than average confidence for the areal details and amounts.
Elsewhere, Florida can expect some scattered diurnally favored
convection, aided by energy aloft to the south of the eastern U.S.
upper ridge. This convection may become more widespread by late
week. Also the Northeast may see mostly light rainfall along a
backdoor front for the first half of the workweek before the
better focus for rainfall around Thursday just ahead of the main
cold front. A front expected to push into the Northwest late in
the week may bring areas of light rainfall.

The eastern U.S./Mississippi Valley upper ridge will promote above
average temperatures by 10-20F from the Plains to the Midwest/Ohio
Valley and the Northeast/Mid-Atlantic Monday-Wednesday, with some
daily record high maximum and minimum temperatures possible. The
backdoor front reaching New England and possibly as far south as
the northern Mid-Atlantic would bring a cooler trend to these
areas though. Meanwhile upper troughing will bring very cool
temperatures to areas from the Intermountain West through northern
Plains early in the week with highs forecast to be 10-20F or below
normal. The flattening pattern aloft will push the initial Plains
cold front eastward while leading to a moderating trend for below
normal temperatures over the central U.S., with mostly
single-digit negative anomalies by Thursday-Friday. The East will
see shrinking coverage of warm temperatures after Wednesday. The
West Coast and into the Great Basin could flip back to warmer than
normal temperatures by around 5-10F Wednesday and beyond, followed
by modest cooler trend on Friday along the immediate West Coast
with the arrival of a Pacific front.

Rausch/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

Hazards:
- Heavy precipitation across portions of the Northern
Plains/Rockies, Mon, May 30.
- Heavy rain across portions of the Central Plains, the Middle
Mississippi Valley, and the Southern
Plains, Tue-Wed, May 31-Jun 1.
- Heavy rain across portions of the Upper Mississippi Valley, and
the Northern Plains, Mon, May 30.
- Severe weather across portions of the Great Plains, and the
Middle/Upper Mississippi Valley, Mon,
May 30.
- Flooding occurring or imminent across portions of the
Central/Northern Plains, and the Upper
Mississippi Valley.
- Flooding likely across portions of the Central Plains.
- High winds across portions of the Central Plains/Rockies/Great
Basin, the Southern
Rockies/Plains, and the Southwest, Mon, May 30.
- Enhanced wildfire risk across portions of the Southern Rockies,
the Central/Southern Plains, and
the Southwest, Mon, May 30.

WPC medium range 500mb heights, surface systems, weather grids,
quantitative precipitation, experimental excessive rainfall
outlook, winter weather outlook probabilities and heat indices are
at:

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