Excessive Rainfall Discussion


[Abbreviations and acronyms used in this product]
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Excessive Rainfall Discussion
NWS Weather Prediction Center College Park MD
349 PM EDT Thu Oct 06 2022

Day 1
Valid 16Z Thu Oct 06 2022 - 12Z Fri Oct 07 2022

...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL ACROSS PARTS OF
NEW MEXICO AND ARIZONA...

...16Z Outlook Update...
The ongoing forecast is on track and no changes are needed. 
Isolated/spotty flash flood potential remains especially as
thunderstorm coverage/intensity increases through peak heating
hours.  The prior discussion below provides additional details on
the Marginal flash flood risk today.

Cook

...Previous discussion...

Model guidance has been trending the convective potential westward
for several runs across Arizona while varying in the exact
placement of the mid/upper level features and the subsequent QPF.
The surface frontal boundary is expected to slow and because
quasi-stationary across southern portions of the Southwest and
across central Texas as the northern stream begins to to pull away
from the upper low/trough over the Southwest. Any of these storms
will have the potential to produce locally heavy rainfall that
could cause excessive runoff in a few areas - especially during
and just after peak heating hours. A Marginal Risk area is in
effect across across Arizona, New Mexico and extreme western Texas.

Campbell


Day 2
Valid 12Z Fri Oct 07 2022 - 12Z Sat Oct 08 2022


...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL ACROSS PARTS OF
SOUTHWEST...

...21Z Outlook Update...

The ongoing forecast is on track.  The main drivers for locally
heavy rainfall will include a nearly stationary upper low over
northwestern Mexico and a strong front that should trend toward
stationary movement while approaching the Front Range late in the
forecast period.  Diurnally driven storms should form across the
Marginal area, posing an isolated flash flood risk.

Cook

...Previous Discussion...

The leading frontal boundary will once again progress southward,
reaching the Gulf by the end of the this period. Behind it,
building high pressure over the central states will send a
weakening secondary cold front southward and westward against the
Front Range, which will hang up near the Southern Rockies and
Southern Plains. Diurnally driven showers and thunderstorms within
the deep pooled moisture will persist across many of the same
locations across the Southwest, but also, extending into portions
of Colorado and the Oklahoma and Texas Panhandles.  This
convective activity has the potential for isolated flash flooding.
A Marginal Risk area for excessive rainfall was raised from
Southeast Arizona to much of New Mexico and small portions of
western Texas.

Campbell

Day 3
Valid 12Z Sat Oct 08 2022 - 12Z Sun Oct 09 2022


...THERE IS A MARGINAL RISK FOR EXCESSIVE RAINFALL ACROSS PARTS OF
SOUTHWEST...

...21Z Outlook Update...
Mid-level troughing will continue across northwestern Mexico,
fostering thunderstorm development during the afternoon and early
evening.  The Marginal risk of flash flooding will continue in
this regime.  More information is available in the previous
discussion below.

Cook

...Previous Discussion...

Convective activity is expected across the Southwest as mid/upper
level features continue to drift westward. Abundant moisture will
still be available to help fuel diurnally driven showers and
thunderstorms over the region. There may be durations of locally
heavy rainfall that lead to an isolated instances of flash
flooding and runoff. Given the westward drifting a Marginal Risk
area was hoisted over much of the Southwest, southern Colorado and
a small portion of California near the Arizona border.

Campbell


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






Last Updated: 349 PM EDT THU OCT 06 2022