Severe Storm Outlook Narrative (AC)
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
ACUS01 KWNS 221951
SPC AC 221950

Day 1 Convective Outlook
NWS Storm Prediction Center Norman OK
0250 PM CDT Thu Mar 22 2018

Valid 222000Z - 231200Z


Isolated to widely scattered thunderstorms are possible today across
parts of the West. A few strong storms may occur over parts of the
San Joaquin Valley, including the possibility of some severe hail.

...20Z Outlook Update...
Some changes have been made, based on the progression of several
perturbations within larger-scale mid/upper troughing advancing into
the Pacific Coast region, as suggested by latest model output, and
supported by observational data.  Potential for stronger convective
development seems to be in the process of becoming confined to
northern portions of the San Joaquin Valley, generally near/between
Merced and Fresno, late this afternoon into early evening.  Although
deep layer shear remains relatively strong, any low tornado risk
seems more unclear due to weak/weakening low-level wind fields and
shear.  Forecast soundings, particularly around Fresno, do continue
to suggest that the environment is becoming conducive to a risk for
thunderstorms capable of producing small to marginally severe-size
hail and gusty winds.

..Kerr.. 03/22/2018

.PREV DISCUSSION... /ISSUED 1129 AM CDT Thu Mar 22 2018/

An extremely moist environment remains across the region via a fetch
of relatively strong deep-layer southwesterly winds to the south of
a prominent deep/closed trough centered off the coast of the Pacific
Northwest and British Columbia. Although clouds and scattered
showers will tend to curb more appreciable destabilization, even
modest cloud breaks later this afternoon into evening could allow
for some stronger updrafts and organized storm modes in the presence
of ample moisture and relatively strong low-level/deep-layer shear.
A relatively well-organized quasi-linear band of showers/few
thunderstorms has already been noted this morning across the
northern valley to the east of Sacramento. In all, a few stronger
storms may materialize across the southern Sacramento Valley and San
Joaquin Valley particularly this afternoon through early evening. A
brief tornado, hail potentially to near-severe levels, and/or gusty
winds could occur.

$$ is the U.S. government's official web portal to all federal, state and local government web resources and services.