Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
1153 AM EDT Fri Jun 12 2026

Day 1
Valid 16Z Fri Jun 12 2026 - 12Z Sat Jun 13 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS OF
EASTERN KANSAS, SOUTHWEST MISSOURI, AND NORTHERN NEW ENGLAND...

...Northern New England...

16Z Update: Quasi-stationary front across ME will be a focal point
for heavy convection late this morning and afternoon. 12z sounding
out of KGYX depicted a robust, deep moist profile with PWATs well-
above normal (1.92"), hitting closer to the 99th percentile when
adjusted for climatology. A stout warm cloud layer presence was
also noted on the morning sounding with the WBZ height right around
13-13.5k ft, a sounding more respectable for environments based in
the south, let alone northern New England. These type of
environmental conditions lend to efficient warm rain processes that
are notorious for overperformance within any precipitation schema,
but especially anything convectively driven. Reports this morning
from just area showers and isolated thunderstorms produced one to
locally two inches of precipitation across portions of New England
in the past 6 hours, a testament to the efficiency of the rainfall.

Complex terrain and flashier streams and rivers across northern New
England offer better potential for flash flood concerns when
convective activity is introduced and today offers one of the
better potentials in quite a long time. Flow will be weak as
steering flow remains meager leading to slow-moving showers and
thunderstorms likely to materialize in proxy to western ME into
northern NH with heavy rain potential of 1-2"/hr plausible in the
stronger cell cores. Considering the light and variable flow within
proximity to the terrain, a quick 1-2+ inches can cause issues in
regards to flash flooding as has been historically the case for
these types of environmental conditions in place. 12z HREF
neighborhood probabilities for >3" are quite robust with a
formidable area of >70% probability for the referenced threshold.
This alone is more than enough to justify a targeted SLGT risk
upgrade for the period, which has been introduced in coordination
with the local ME offices. Timing for the threat will occur between
now and sunset with the loss of diurnal heat flux likely to put an
end to the threat as a cold front approaches out of Quebec.

Kleebauer

...Eastern Kansas into Southwest Missouri...

16Z Update: Highly conditional setup for significant rainfall
exists across portions of the central CONUS with the main axis of
potential aligned over eastern KS down into southwest MO. Recent
rainfall over the region has provided a decent soak to the top soil
layer with elevated streamflows being seen across portions of the
above area. A mid-level vorticity maxima is forecast to motion out
of the adjacent High Plains of eastern CO and western KS with a
migration eastward within the mean flow aloft. Some CAMs are pretty
aggressive with the potential for convection to fire across
eastern KS and motion southeast into MO as we move into the back
end of the forecast period. The timing of the disturbance entering
the area coupled with a nosing 850mb LLJ over KS would in theory
aid to the development of convection with a rapidly improving mid-
level shear profile capable of sustaining a stronger mesocyclone
initiation leading to a focus of heavy precipitation. The
HRRR/NAMNest are the most aggressive with this signature with the
AIFS also inferring at least the threat of some convective
development in that 06-12z Sat window. Recent HREF neighborhood
probs for >2" have adjusted up closer to 20-30%, doubling the
previous probabilities from the last forecast cycle. HREF EAS still
remains weak in the depiction which exemplifies the conditional
nature of the threat, and a split in the guidance on handling the
convective potential and eventual evolution.

Despite the conditionality of the risk, there was a SLGT risk added
to the area for two reasons. The first was the antecedent soil
moisture and streamflows are currently conducive for flash flood
capabilities as any heavy rainfall will pose a threat for run off
and hydrologic issues. The second is the environmental conditions
leading in are genuinely favorable for locally higher rates within
any cells that do materialize as PWATs remain 1-2 standard
deviations above normal across the region. Models that do show the
rapid convective development and impacts are depicting rates
between 2-3"/hr at peak, a range that would easily breach the
current hourly FFG threshold in place over much of the area
(1-1.5"/hr). In coordination with the local WFO's across the area,
the SLGT risk was added for the conditional threat.

Kleebauer

...West Texas...

16Z Update: Modest theta_E ridge across southwest TX into the High
Plains of NM will allow for sufficient low to mid-level buoyancy
this afternoon ahead of a weak diffluent axis approaching from the
west during the period. MUCAPE between 1000-2500 J/kg will be
positioned across the western RGV up through the mountains of
southwest TX through the Upper Trans Pecos, plenty enough
instability to maintain isolated strong convective cores to
materialize across the area. Initiation will likely occur over the
Sacramento Foothills down into the Davis Mountains with cells
likely drifting eastward off the terrain and migrating into the
adjacent High Plains. Isolated flash flood concerns will arise from
the convection in the area, enough of a signal to warrant a
continuation of a MRGL risk across the region.

Kleebauer

...Central and Southwest Florida...

16Z Update: No changes to the previous forecast as the 12z guidance
remains consistent in its interpretation of locally heavy rainfall
across central and southwest FL this afternoon with the main
threat along the sea breeze(s) and any convergence. 12z HREF
neighborhood probs for >5" are between 40-70% across south-central
FL towards the southwest FL coast, a signal relevant enough to
maintain continuity from previous forecast.

Kleebauer

..Previous Discussion..
Anomalous moisture will reside over southwest and central portions
of the Florida Peninsula today, though it should be a little less
in terms of PW compared to Thursday. Convection along the sea
breezes should produce very heavy rainfall that could lead to
flooding concerns for urban areas in Central and Southwest Florida.
A Marginal Risk remains in effect with Tampa Bay removed due to CAM
consensus to the east/south of there.

Jackson


Day 2
Valid 12Z Sat Jun 13 2026 - 12Z Sun Jun 14 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE
CENTRAL PLAINS THROUGH THE MIDDLE MISSISSIPPI VALLEY INTO THE
LOWER OHIO VALLEY...

An upper trough swings down the northern Plains Saturday, pushing a
cold front across the central Plains and Midwest through Saturday
night. Meanwhile, a warm front tracks from Oklahoma through
Illinois ahead of the cold front, creating focus for strong
convergence in a very warm, moist, and unstable air mass. Resultant
heavy thunderstorms look to organize and repeat from the central
Kansas/Oklahoma border through central/southern Illinois and
western Kentucky where the Slight Risk was expanded a bit.
Particular focus for heavy rain remains near the Kansas/Missouri
border where a higher than normal Slight Risk is noted. Scattered
instances of flash flooding can be expected and a targeted Moderate
Risk is possible.

More isolated heavy thunderstorms are also expected over the
eastern New Mexico and west Texas terrain and nearby plains where
the Marginal Risk remains.

The Marginal Risk was removed from most of Michigan based on the
00Z high-res solutions available with little PW anomaly noted.

Jackson


Day 3
Valid 12Z Sun Jun 14 2026 - 12Z Mon Jun 15 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
TEXAS AND THE LOWER MISSISSIPPI VALLEY...

...Southern Rockies, Texas to Southeast...

A cold front pushes down the Southern Plains into Texas on Sunday.
This shunts the heavy rain focus south of Saturday and provides a
strong focus for convective development in a rich Gulf-sourced
moisture environment. PW anomalies are 2 to 3 sigma above normal
across Texas (south of the Panhandle) by that afternoon with 2
sigma anomalies expanding east to Alabama by late Sunday night.
Expansion of the Slight Risk to both North Texas and the Houston
metro areas are warranted given the environment as well as the 00Z
consensus of the UKMET and EC-AIFS for the Houston area, and the
RRFS and RDPS for North Texas. Furthermore, a decent signal for
lasting thunderstorm development is over West Texas in the Permian
Basin into the Concho Valley, so a Slight Risk was raised there as
well.

Additional terrain driven diurnal activity is expected over the
Southern Rockies/Sacramento and Davis Mtns. This activity should
spread southeast through the evening, so the Marginal Risk was
expanded over the southern High Plains.

A surge of moisture up the southern Appalachians Sunday morning
brings enough of a heavy rain threat for a Marginal Risk expansion
up to the westernmost section of Virgina.
...Hampton Roads and Delmarva...
Southwesterly low level flow from the Carolinas bring 2" PW to the
Mid- Atlantic coast Sunday afternoon ahead of a cold frontal
passage that night. Evening thunderstorms should be heavy and slow
enough to warrant a Marginal Risk.
Jackson


Day 4 and Day 5

Valid 12Z Mon Jun 15 2026 - 12Z Wed Jun 17 2026
...A SLIGHT RISK OF EXCESSIVE RAINFALL EXISTS FOR PORTIONS OF THE
SOUTHERN PLAINS, LOWER MISSISSIPPI VALLEY, AND THE SOUTHEAST...

Overall, not much change from the previous forecast, with the
overnight guidance continuing to present a good signal for highly-
efficient training storms along a slow-moving front settling into
the region.

Models continue to show a cold front settling slowly south though
the southern Plains, lower Mississippi Valley, and the Southeast as
shortwave energy gradually amplifies a broad upper trough centered
along the Mississippi Valley on Monday. A deepening pool of
moisture along the front, fed by southerly low level inflow from
the western Gulf, will fuel the potential for highly-efficient
showers and storms. Guidance continues to show PWs increasing to
2.25 inches (2.5 to 3 std dev above normal) along and ahead the
front from south South Texas to southern Alabama on Monday.
Interacting with this moisture is expected to be an area of
enhanced ascent provided by right-entrance region upper jet forcing
positioned along the base of the amplifying trough. In addition to
the deep moisture and large-scale ascent, repeating storms are
expected to raise the potential for heavy amounts and flash
flooding concerns. A Slight Risk was maintained from southeastern
Texas to central and southern Alabama on Day 4.

By Tuesday, the upper trough axis begins to shift to the east,
pushing the front, deeper moisture, and the better chance for heavy
rain farther south and east along the Gulf Coast. For Day 5, a
Slight Risk was drawn from southeastern Louisiana to southwestern
Georgia.

While Slight Risks were drawn for both periods, given the potential
for several inches of rain in some locations, an upgrade to a
Moderate Risk may be required in future updates if the signal
persists as the event draws nearer.

Pereira


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