Fire Weather Outlook Discussion

Day 1 - Storm Prediction Center Norman, Oklahoma

FNUS21 KWNS 130748
FWDDY1

Day 1 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0147 AM CST Thu Dec 13 2018

Valid 131200Z - 141200Z

...CRITICAL FIRE WEATHER AREA FOR FAR SOUTH TEXAS ALONG THE RIO
GRANDE RIVER VALLEY...

...Synopsis...
The primary synoptic feature for fire weather concerns will be a
vigorous cut-off low centered over Texas.  This feature will
decelerate while migrating slowly east-southeastward.  A belt of
very strong (80-90 kt) mid-level flow will orient cyclonically
around the trough.  Meanwhile, downsloping flow and vertical mixing
processes will create dry and windy conditions across portions of
eastern New Mexico into south Texas.  Elsewhere, a strong offshore
pressure gradient will persist across portions of southern
California, though fuels may not support widespread fire risk in
most areas.

...Eastern New Mexico southward into Deep South Texas...
Strong mid-level flow and vertical mixing processes will result in
widespread areas of 30-35 mph north/northwesterly surface winds
across elevated and critical areas - peaking around late-afternoon
and early evening.  Gusts exceeding 50 mph are possible as well.
Surface RH values will only flirt with near-critical RH values
through peak heating (i.e., around 20-30%).  Furthermore, light rain
was falling across south Texas and vicinity, and this precipitation
should end early morning D1/Thursday.  Current expectations are that
the strong winds and drying low-levels will quickly dry dormant
fuels (especially finer fuels) and support potential for rapid fire
spread by afternoon.  Critical delineations are focused in areas
where RH values should fall to around 20%.  Farther northwest into
New Mexico, surface temperatures will be substantially cooler (40s
and 50s F), though single-digit dewpoints, 18-25% minimum RH, and
dormant fuels should still support large fire potential.

...Southern and southwestern California...
Coastal ranges east of San Diego and vicinity will experience gusty
easterly winds (20-25 mph) at times along with RH values falling to
around 20-30% during the afternoon.  Recent rains have impacted
fuels across the region, and fuel states may not support rapid fire
spread except on a localized basis.  Locally elevated fire weather
is expected.

..Cook.. 12/13/2018

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

$$