Day 1 Convective Outlook  
NWS Storm Prediction Center Norman OK
0641 PM CST Fri Jan 17 2025

Valid 180100Z - 181200Z

...NO SEVERE THUNDERSTORM AREAS FORECAST...

...SUMMARY...
Scattered, generally weak, thunderstorm activity is possible tonight
across parts of the lower Mississippi into Tennessee Valleys and
adjacent Gulf Coast vicinity.

...01Z Update...
Downstream of building mid/upper ridging across the northeast
Pacific through Alaska/Yukon vicinity, large-scale mid/upper trough
amplification is underway along a positively tilted axis roughly
extending across the Hudson Bay vicinity into the lee of the
southern Rockies.  This has been preceded by the east-northeastward
acceleration of initially significant troughing emerging from the
southern mid-latitude/subtropical eastern Pacific, which is becoming
increasingly sheared across the southern tier of the United States.
One still notable embedded short wave perturbation is in the process
of accelerating east-northeast of the southern Great Plains, and
forecast to approach the southern Appalachians by 12Z Saturday.

In response to the aforementioned short wave, low-level warm
advection now overspreading the southeastern Great Plains and lower
Mississippi Valley will continue to develop eastward tonight.  Even
with a sizable westerly component to the low-level wind fields, it
appears that elevated moisture return emanating from a slowly
modifying boundary layer over the Gulf of Mexico will contribute to
weak destabilization.  Latest model output continues to suggest that
this may become sufficient for scattered, generally weak,
thunderstorm activity as cooling aloft begins to overspread areas
across and east/southeast of the lower Mississippi Valley by around
05-06Z.

..Kerr.. 01/18/2025

Day 3-8 Fire Weather Outlook  
NWS Storm Prediction Center Norman OK
0359 PM CST Fri Jan 17 2025

Valid 191200Z - 251200Z

...Southern California...
Within the base of a highly amplified, positive-tilt large-scale
trough over the West, an embedded shortwave trough will track
southeastward across the Southwest into the southern Rockies from
Day 4/Monday into Day 5/Tuesday. At the same time, an amplified
upper ridge will build over the eastern Pacific, favoring
strengthening surface high pressure over the Intermountain West.
This pattern will result in a strengthening offshore pressure
gradient across southern CA (-6 to -8 mb LAX-DAG gradient), with
moderate midlevel support across the area. Given reasonably good
agreement in the development of single-digit to lower teens RH and
strong/gusty east-northeasterly surface winds, 70-percent Critical
probabilities have been introduced for the wind-prone Santa Ana
corridor (much of Ventura County, northern/western Los Angeles
County, and portions of northern San Bernardino County) for Day
4/Monday into Day 5/Tuesday. 

From Day 6/Wednesday into Day 7/Thursday, another shortwave trough
should track southeastward across the Great Basin and Southwest,
while an upstream ridge builds over the eastern Pacific. While
noteworthy differences are evident among the medium-range guidance
regarding this overall evolution, current indications are that
surface high pressure will once again strengthen over the
Intermountain West, favoring the potential for another dry offshore
wind event across southern CA. 40-percent Critical probabilities
have been added for Day 6/Wednesday into Day 7/Thursday, and higher
probabilities could eventually be needed as the details become more
clear.

..Weinman.. 01/17/2025

...Please see www.spc.noaa.gov/fire for graphic product...