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477
FNUS28 KWNS 292102
FWDD38

Day 3-8 Fire Weather Outlook
NWS Storm Prediction Center Norman OK
0401 PM CDT Wed Mar 29 2017

Valid 311200Z - 061200Z

An active synoptic pattern over the Southwest will foster multiple
episodes of elevated to critical fire weather conditions in the
southern Rockies and adjacent Plains during the extended period.  At
the beginning of the period, an strong mid-level flow will cut off
over the western Great Basin while migrating southeastward toward
central New Mexico by D5/Sun and the Red River Valley of Oklahoma
and Texas by D6/Mon.  Strong mid-level flow will traverse dry areas
of the Southwest, southern Rockies, and southern High Plains during
this time.  Another upstream trough will affect the Intermountain
West from D6/Mon into D7/Tue, with continued strong mid-level flow
impacting the southern Rockies/High Plains and fostering heightened
fire weather potential on those days.

...D3/Fri and D4/Sat - Portions of the Southern Rockies and adjacent
Southern High Plains...
Southwesterly mid-level flow will strengthen dramatically (perhaps
exceeding 80 kts) across the region upon approach of the mid-level
low.  As this occurs, vertical mixing processes and a favorable
surface pressure gradient (owing to a 996 mb low in far southeastern
New Mexico) will foster very strong surface flow, perhaps exceeding
50 mph in a few areas of southern New Mexico and adjacent areas of
west Texas.  This, in conjunction with a critically dry airmass in
place, will likely foster widespread critical conditions in the
region, with higher-end fire weather possible in regions of
strongest surface flow over southern New Mexico.

On D4/Sat, surface flow should weaken some in conjunction with a
weakening mid-level jet and a slightly weaker surface low in
portions of the Texas South Plains/northwest Texas.  Models are
consistent in depicting enough lingering low-level flow in an axis
from the Transpecos to the Midland area for 70%/critical
probabilities to be included in this forecast.  Lower (40%)
probabilities will exist surrounding this region and northeastward
into the Texas South Plains, although a lot of this fire weather
potential will depend on fuel recovery from widespread wetting rains
that occurred on Tue 28 Mar and greening of fuels may temper this
threat such that critical conditions are unlikely.  This will be
monitored in future outlooks.

...D3/Fri and D4/Sat - Portions of the Lower Colorado River
Valley...
Areas of dry northerly flow will foster elevated fire weather
conditions in these areas during peak heating hours of both days.
Latest fuel guidance and collaboration with local WFOs regarding
fuels in the region suggest that fuels may not be critically dry
enough to support a higher fire weather threat especially in the
northern periphery of the delineated areas.  40% probabilities will
remain in place for this outlook to address the attendant threat.

...D5/Sun - Portions of the Rio Grande Valley...
40% probabilities have been maintained for this time period,
although they have been confined to areas near the Rio Grande.
Models are trending toward cooler surface temperatures during the
period of peak heating, which may keep surface RH values from
falling too far below 20% in the region.

...D6/Mon through D7/Tue - Southeastern Arizona, Southern through
Eastern New Mexico, and much of West Texas...
Dry westerly surface flow will once again increase across the region
on both days in response to a strengthening surface trough in the
lee of the Rockies and strengthening mid-level flow in advance of a
mid-level wave traversing the Intermountain West.  The overall
synoptic pattern favors widespread critical fire weather conditions
on both of these days.  Confidence of sufficiently strong surface
flow, low RH, and dry fuels is highest from far southeastern Arizona
eastward into west Texas on D6/Mon and 70%/critical probabilities
have been added for this time period to reflect this increased
confidence.  It appears likely that additional areas will experience
critical conditions on both days, although will hold off on higher
probabilities for portions of the region for greater confidence and
model consistency.

..Cook.. 03/29/2017

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

$$



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