925
FOUS30 KWBC 052017
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
417 PM EDT Thu Jun 5 2025

Day 1
Valid 16Z Thu Jun 05 2025 - 12Z Fri Jun 06 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
THE SOUTH-CENTRAL PLAINS...

...Central to Southern Plains...

With scattered to widespread storms expected across much of the
country in an active late Spring pattern, a locally higher threat
for flash flooding exists over portions of the Central/Southern
Plains where greater coverage of heavy rainfall is expected with
the development of a convective system later this evening. An
environment very conducive to thunderstorm development will evolve
today as a weak triple point develops in southeastern Colorado with
high moisture, instability in place south of a warm front and
ahead of a dryline extending southward through the southern High
Plains. Afternoon convection developing off the Raton Mesa/High
Plains will feed off the higher theta-e air and strengthening low
level flow ahead of the triple point into the evening hours,
expanding in coverage as cold pools combine/mature and with any
additional development eastward along the warm front. Anomalously
high moisture in place may lead to rain rates upwards of 2-2.5" per
hour. While the system should remain progressive, the high rain
rates and storm coverage will bring the threat for locally heavy
rain totals as high as 3-4" and scattered instances of flash
flooding along the system path. This path is currently most likely
from southwestern Kansas/the Oklahoma Panhandle/the northeastern TX
Panhandle later this evening east-southeast through southern
Kansas and northern Oklahoma into the early morning hours Friday.
Elsewhere, additional individual storms ahead of the dryline
southward through the Texas Panhandle/west Texas will also bring
the threat for some locally heavy downpours and isolated flash
flooding.

...Southern Great Basin into the Southern to Central Rockies...

Another day of scattered to widespread diurnal convection is
expected throughout the region with upper-troughing and colder
temperatures aloft and the presence of a lingering frontal
boundary. Anomalously high moisture (PWs upwards of 2-2.5 standard
deviations above the mean) may lead to some locally heavy downpours
with rain rates of 0.5-1" bringing the threat for some isolated
instances of flash flooding, particularly for terrain sensitive
areas and burn scars.

..Lower Lakes, OH Valley into the Mid to Lower MS Valley...

PW values also expected to remain above average in the vicinity of
the nearly stationary frontal boundary stretching from the lower
Lakes, southwest into the OH Valley and Mid to Lower MS Valley. A
broad marginal risk area was maintained from previous issuances for
localized heavy rainfall and isolated runoff issues. The previous
marginal risk area was modified to better reflect latest model
consensus on the moderate to locally heavy qpf axis.

...Eastern and Coastal Carolinas...

Thunderstorms continue this morning/early afternoon in a modifying
airmass lifting northward through the central/eastern/coastal
Carolinas east of a weak surface low. Anomalously high moisture
values streaming in from the Atlantic (PWs 2-2.5 standard
deviations above the mean) and increasing instability (ML CAPE
around 1000 J/KG) may lead to some efficient rainfall rates of 1-2"
per hour. While the heaviest rainfall is expected to remain
offshore and FFGs remain high, these rates may lead to some
isolated flash flooding concerns, particularly for coastal
locations that may see a few repeated rounds of storms lifting
northward. The threat should diminish through the evening hours as
the low moves offshore.

Putnam

Day 2
Valid 12Z Fri Jun 06 2025 - 12Z Sat Jun 07 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR MUCH OF
OKLAHOMA INTO THE KANSAS, OKLAHOMA, MISSOURI, ARKANSAS BORDER
REGION...

...2030Z Update...

...Oklahoma into the OK/KS/MO/Ar border area...

Ongoing convection associated with an MCS passing through eastern
Oklahoma during the day 1 period may continue into day 2 Friday
morning, with a continued risk for locally heavy rainfall and
scattered flash flooding. Otherwise, the previous forecast remains
on track, and similar to day 1 in both nature and location, with
the expectation that afternoon/evening thunderstorms developing
ahead of a triple point low located over the central/southern High
Plains will grow upscale into an MCS. This system should track
east-southeastward through Oklahoma late Friday night/early
Saturday with an attendant risk for locally heavy rainfall rates of
1-2" and totals of 2-4" leading to scattered instances of flash
flooding.

...Mid MS, Ohio, and Tennessee Valleys...

A complex forecast is apparent for this region given the potential
for an ongoing and/or influence from an overnight MCS Thursday
night/Friday morning. Hi-res guidance suggests that an MCS
developing over the central/southern High Plains and passing
eastward through the central/southern Plains Thursday night/Friday
morning will continue eastward into the Middle
Mississippi/Ohio/Tennessee Valleys Friday afternoon. Any sustained
convection may also be augmented by redevelopment along associated
outflow boundary(s), which would help to focus what would be a more
nebulous distribution of storms and lead to more widespread,
higher rainfall totals supportive of a greater flash flood threat.
Regardless of the influence of this MCS, the prior forecast remains
on track. The presence of an anomalously moist, unstable airmass
along and ahead of the quasi-stationary frontal boundary will be
enough to trigger scattered to widespread thunderstorms capable of
locally heavy rainfall and at least isolated flash flooding.

...New England...

A frontal wave forming along a cold front draped through southern
New England westward through the Lower Great Lakes will help
encourage a moist, southerly return flow from the Atlantic
northward through New England during the day Friday. Multiple
shortwave passages and a warm conveyer belt setup will lead to
multiple rounds of thunderstorms producing locally heavy rainfall.
An axis with a potentially higher threat was noted from the eastern
Catskills/greater Albany northeastward through northwestern
Massachusetts, southern Vermont, and central New Hampshire,
particularly given the sensitivity of the more complex terrain
through the region. However, with the latest hi-res guidance still
relatively localized on higher totals, have held at a Marginal Risk
for now pending a confirmation/increase in potentially more
widespread, higher totals.

Putnam

...Previous Forecast...

...Oklahoma into the OK/KS/MO/Ar border area...
Another round of shortwave energy forecast to drop east
southeastward from the Central Rockies into the Central to Southern
Plains Friday into Friday night/early Saturday. This will support
potential for another round of organized convection in the vicinity
of the west to east oriented frontal zone. PW values along this
front will remain above average...2+ standard deviations above the
mean, supporting heavy precip potential. There is fairly good model
consensus for an axis of heavy rains along this front across much
of OK into the OK/KS/MO/AR border region. Only some slight changes
to the previous slight risk area to reflect this qpf axis
consensus.

...Southern Great Basin into the Central to Southern Rockies...
Not a lot of changes expected to the large scale flow from day 1
across the southern Great Basin into the Central Rockies. PW values
forecast to remain above average with additional shortwave energy
moving across the region in the west south west flow aloft. This
should support another day of widespread scattered convection and
localized heavy rain and isolated runoff issues. The marginal risk
was extended back across these areas to be more similar to the day
1 period given the similar overall conditions day 2.

...Mid MS Valley, OH Valley into New England...
Similar to the day 1 period, an axis of above average PW values
will stretch along the slow moving front stretching from the Mid MS
Valley, OH Valley into New England. There is good model consensus
on a broad region of moderate to locally heavy precip amounts along
this front. Only some minor changes to reflect the latest model
qpf axis consensus made to the previous broad marginal risk area
across these regions.

Oravec


Day 3
Valid 12Z Sat Jun 07 2025 - 12Z Sun Jun 08 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS THE LOWER
ARKANSAS VALLEY, LOWER MISSISSIPPI VALLEY INTO THE LOWER TENNESSEE
VALLEY...

...2030Z Update...

The prior forecast remains on track with respect to the Southern
Plains eastward through the Lower Mississippi and Tennessee Valleys
with only minor areal adjustments based on the latest 12Z
guidance. Further north, forecast rainfall totals have come down in
New England, with guidance now suggestive of only some relatively
isolated totals around 1". Have maintained a Marginal Risk for now
but given the lower totals and more progressive nature of the cold
front Saturday, a threat for even isolated flooding may not
ultimately materialize and will be re-evaluatd in subsequent
outlooks.

Putnam

...Previous Forecast...

The second round of height falls moving into the Central to
Southern Plains day 2 will continue to push east southeast toward
the Mid to Lower MS Valley, OH and TN Valleys. Upper difluence is
forecast to be well defined Saturday into Saturday night/early
Sunday in an axis of above average PW values that will remain along
the west to east oriented frontal boundary across these areas.
This should support potential for another round of organized
convection along this front. There is some spread with the qpf
axes, but consensus that heavy amounts are possible along this
front. The previous slight risk area was expanded eastward
considerably from eastern OK, across much of AR, western TN and
northern MS.

...Northern New England...
A sharpening northern stream trof will push surface low pressure
across northern New England on Sunday. There is fairly good model
consensus for moderate to locally heavy precip totals across
northern New England. Only some slight changes to the previous
marginal risk area, extending it into all of northern Maine to
cover the model qpf spread.

Oravec


Day 1 threat area: https://www.wpc.ncep.noaa.gov/qpf/94epoints.txt
Day 2 threat area: https://www.wpc.ncep.noaa.gov/qpf/98epoints.txt
Day 3 threat area: https://www.wpc.ncep.noaa.gov/qpf/99epoints.txt