FOUS30 KWBC 120806
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
406 AM EDT Sun Oct 12 2025

Day 1
Valid 12Z Sun Oct 12 2025 - 12Z Mon Oct 13 2025

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF
SOUTHERN ARIZONA AND NEW MEXICO...

...Southwest...
Deep moisture, fortified with the remnants of Tropical Cyclone 
Raymond, will remain in place over portions of southern Arizona and
New Mexico. This morning's mesoanalysis shows PWs of 1.25-1.6 
inches (3-4 std dev above normal) covering much of region. This 
moisture along with increasing large-scale ascent, provided by an 
approaching upper trough, will support another day of widespread 
showers and storms capable of producing moderate to heavy amounts. 
Maintained a Slight Risk covering much of southern Arizona and a 
small portion of southwestern New Mexico. Both the HREF and RRFS 
neighborhood probabilities indicate locally heavy amounts 
exceeding 2 inches are likely within this region, with some 
potential for amounts over 3 inches, especially across parts of 
southern Arizona.

...Eastern Southern Carolina and Southeastern North Carolina...

The initial low of what is expected to evolve into a two feature 
system is forecast to linger along the coast in the vicinity of the
North and South Carolina border today. Deeper moisture will remain
as well, with many of the 00Z models, including the globals, 
showing a notable signal for locally heavy amounts developing later
today. While instability will be limited, deep saturation through 
the column, and tall, skinny CAPEs are expected to support very 
efficient rains, promoting heavy amounts. Both the HREF and RRFS 
showing high probabilities for additional amounts over 3 inches 
today across parts of the region. These amounts may raise runoff 
concerns, especially for those areas where significant rains have 
already occurred. Therefore a Marginal Risk was introduced for 
areas where the hi-res ensembles indicate the heaviest amounts are 
most likely to fall.

...Northern Mid Atlantic to Southern New England Coasts...

North of its parent, a secondary, triple-point low is forecast to 
develop near the northern Mid Atlantic coast. There remains some 
model uncertainty regarding if and to what degree this low will 
become the dominant surface feature. Despite the differences, 
there is broad agreement that strong, low level easterly winds, in
combination with strong mid-to-upper level forcing, will support 
widespread precipitation from the northern Mid Atlantic coastal 
region to central New England, with heavy amounts expected along 
the coast. These heavy rains may compound what are likely to be 
poor ground conditions attributed to ongoing coastal flooding. 

Pereira


Day 2
Valid 12Z Mon Oct 13 2025 - 12Z Tue Oct 14 2025

...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL ACROSS PORTIONS OF
SOUTHEASTERN ARIZONA, SOUTHWESTERN NEW MEXICO, AND SOUTHERN COLORADO...

...Southwest to the Central Rockies...

Lingering deep moisture over southern Arizona and New Mexico will
be drawn north ahead of an upper trough amplifying over California.
This moisture along with the broad-scale ascent afforded by the 
upper trough will support one more day of showers and storms across
the Southwest, but this time shifting a bit further east while 
extending north across New Mexico into the central Rockies. With 
drier air working into southwestern Arizona, the potential for 
heavy rain and the threat for flash flooding will become more 
limited across that area. However, further to the north and east, a
Slight Risk was maintained along eastern portions of the Mogollon 
Rim into southeastern Arizona and southwestern New Mexico. There 
remains a notable signal for additional moderate to locally heavy 
amounts across that area. Also remaining is a Slight Risk in a 
portion of the San Juan Mountains, where models show deep 
persistent southerly winds, along with favorable upper forcing, 
supporting heavy totals as well.

...Northern and Central California....

Models remain in generally good agreement, showing an anonymously 
deep upper developing and dropping south along the West Coast from 
the Pacific Northwest to Northern California this period. Moisture 
with this system will be relatively modest initially, but enough 
to raise moisture anomalies to 1-2 std dev above normal along its 
axis of strong onshore flow. This along with strong forcing may be 
sufficient to produce locally heavy amounts, with isolated runoff 
concerns, especially in the upslope regions of the coastal ranges 
and the Sierra foothills below the snow line.

....Northeast...

Questions remain as to how the low developing along the Northeast 
coast will continue to evolve, but most agree on at least a 
localized threat for heavy rain spreading north from southern New
England up along the coast to areas perhaps as far north as coastal
Maine. Given the uncertainty, kept the Marginal Risk centered to 
the area where the GEFS and ECENS both indicate that amounts 
exceeding an inch are most likely.

Pereira


Day 3
Valid 12Z Tue Oct 14 2025 - 12Z Wed Oct 15 2025

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL OVER PORTIONS OF
CENTRAL TO SOUTHERN CALIFORNIA, NEW MEXICO, AND WEST TEXAS...

...Central to Southern California...

A deep upper low will continue to dig south early in the period
before turning east across California into the Great Basin this
period. Before turning inland, this system will support an ongoing
threat for heavy precipitation, with the focus shifting south along
with its associated axis of deep onshore flow across Southern 
California into the southern Sierra Nevada. A Marginal Risk was 
drawn south along the Southern California Transverse Ranges, where
0.75-1 inch PWs interacting with favorable upper jet dynamics and 
orographic ascent are expected to support rainfall amounts of 1-2 
inches along the favored terrain. These amounts may produce 
isolated runoff concerns, especially over vulnerable burn scar 
areas. A Marginal Risk was also maintained further to the northeast
along the southern Sierra foothills, where similar amounts are 
expected below the snowline.

...New Mexico and West Texas...

As drier air continues to spread east across Arizona into eastern
New Mexico, PWs anomalies will remain high across portions of
central New Mexico and West Texas where strengthening low level 
easterly winds will add to the lingering moisture. With the 
increase in moisture, the GFS shows PW anomalies remaining over 3 
std dev above normal across much of the highlighted areas. This 
along with daytime heating will support additional shower and 
thunderstorm development, with some potential for locally heavy 
amounts and isolated runoff concerns. 

Pereira
$$
--- SBBSecho 3.28-Linux
 * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (618:250/1)