FOUS30 KWBC 160950
QPFERD

Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
550 AM EDT Thu Jul 16 2026

Day 3  Valid 12Z Sat Jul 18 2026 - 12Z Sun Jul 19 2026

...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FROM WEST TEXAS AND
SOUTHERN NEW MEXICO TO SOUTHERN UTAH...

...Western U.S....

An expansive monsoonal convective pattern will continue, prompting
the inclusion of a Slight Risk stretching from West Texas and
southern New Mexico northwestward across Arizona and into southern
Utah. Overnight guidance indicated a notable uptick in low level
moisture transport into these region on Saturday. This surge will
act to revitalize the potential for additional rounds of high
rainfall rate convective cores capable of producing flash flooding.

Once again, the combination of anomalous moisture and instability
will support highly efficient rainfall rates within the stronger
storms. The threat of rapid runoff and flash flooding will be
elevated across the complex terrain, normally dry washes, and slot
canyons, as well as over highly sensitive soils and wildfire burn scars.

...Ohio Valley/Central and Southern Appalachians to the Mid
Atlantic and Northeast...

The core of the high-PW airmass will continue to shift east, with
moisture pooling ahead of a strong cold front dropping south
across the Northeast. Strong synoptic forcing, driven by an
amplifying trough over the Northeast and favorable upper jet
dynamics, will support an axis of organized storms from the upper
Ohio Valley into the Northeast. Given the high PWs and strong
forcing, heavy rainfall rates producing at least localized runoff
concerns are expected. Given the uncertainty regarding where the
axis of heaviest rains will occur, maintained a Marginal Risk for
now. However, a targeted Slight Risk may be introduced in future
updates if confidence increases.

Pereira
 

Day 4 and Day 5  Valid 12Z Sun Jul 19 2026 - 12Z Tue Jul 21 2026

...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ACROSS PORTIONS
OF THE WEST ON DAYS 4 AND 5, THE VIRGINIA TIDEWATER ON DAY 4, AND
PORTIONS OF FLORIDA ON DAYS 4 AND 5...

...Western U.S...

A traditional Monsoonal pattern will continue across the Western
CONUS with scattered to widespread bouts of heavy rainfall across
much of the Desert Southwest up through the Great Basin with an
northern inflection into portions of the Rockies. Ridging will
prevail across the west as we move through the weekend into early
next week with a solidified Monsoonal trough positioned over AZ
down through Mexico. Even at leads, there's a well- defined axis
of elevated instability coupling with PWAT anomalies between +2 and
+3 standard deviations positioned from the Great Basin to points
south with the strongest anomalies situated over NV and UT was
assessing both the ECENS and NAEFS anomaly forecast. QPF maxima
are currently situated within the Mogollon Rim and portions of
southern UT, both of which are the more susceptible areas given the
persistence of heavy rainfall leading in, plus the complex
topography and slot canyon allotment. This is really a seasonal
setup which could likely spur short term upgrades in spots as we
move closer to both the D4 and D5 time frame. Broad MRGL risks
exist for both days in similar locations outlining much of the
aforementioned area(s) above.

...Florida...

Models continue to depict heavy rainfall across the western coast
of FL on D4 (Sunday), spreading further east towards the northern
half of the state on D5 (Monday) thanks to developing mid-level
disturbance over the eastern Gulf. General model consensus is for a
development of heavier rains across the western FL coast with a
northern inflection into the Florida Big Bend thanks to increasing
low-level convergence on the eastern flank of a weak low center
progged off the coast. Ensemble QPF for both periods indicate
multiple inches of rain possible which could enhance further if
there is a greater likelihood of tropical cyclogenesis as noted via
the latest National Hurricane Center T.W.O for a disturbance of
interest (Disturbance 2) at 20% chance for development the next
7-days. This is a period to monitor for the prospects of this being
something more organized which models might not have a great grasp
of yet considering the lead time, and the slow maturation of any
organized low the next 5-7 days. For now, MRGL risks exist on both
D4 and D5 for the threat of heavy rainfall.

...Virginia Tidewater into Northeast North Carolina...

Slow-moving front will make headway through southeastern VA and
northeastern NC by Sunday with a deep moisture pooling anticipated
along and ahead of the front which will likely lead to areas of
heavy thunderstorms prior to fropa. Ensemble consensus lends
credence to a localized QPF maxima positioned somewhere around the
VA Tidewater through the northeastern corner of NC, coincident
with the progged frontal positioning around the time of Sunday
afternoon. PQPF for >1" is between 20-40% across the region which
at D4 is formidable enough to monitor closely. Considering some of
the more appreciable outputs via the global deterministic and bias
corrected ensemble, and in coordination with the local Wakefield,
VA WFO, opted to add a D4 MRGL risk for the threat, highlighting
that Tidewater area down into northeastern NC.

Kleebauer
$$
--- MultiMail/DOS
 * Origin: capitolcityonline.net * KY, USA (618:250/10)