Red Flag Warning 14, NWS Pocatello, ID

950 
WWUS85 KPIH 100914
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
314 AM MDT Mon Sep 10 2018

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
MONDAY FOR STRONG GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE 
WEATHER ZONES 422, 475 AND 476...

IDZ422-475-476-110300-
/O.CON.KPIH.FW.W.0014.180910T1800Z-180911T0300Z/
Sawtooth Range/Northern Sawtooth NF-
East Salmon River Mountains/Salmon NF-
Lemhi and Lost River Range/Challis NF-
314 AM MDT Mon Sep 10 2018

...RED FLAG WARNING REMAINS IN EFFECT FROM NOON TODAY TO 9 PM MDT
THIS EVENING FOR GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE
WEATHER ZONES 422, 475 AND 476...

* AFFECTED AREA...Fire Weather Zone 422 Sawtooth Range/Northern 
  Sawtooth NF, Fire Weather Zone 475 East Salmon River 
  Mountains/Salmon NF and Fire Weather Zone 476 Lemhi and Lost 
  River Range/Challis NF.

* WINDS...Southwest 15 to 25 mph with gusts up to 35 mph.

* RELATIVE HUMIDITY...As low as 10 to 15 percent.

* IMPACTS...Strong gusty winds and dry conditions could cause new
  or existing fires to spread rapidly.


PRECAUTIONARY/PREPAREDNESS ACTIONS...

A red flag warning means that critical fire weather conditions
are either occurring now, or will shortly based on these criteria
for Southeastern Idaho:

* Relative humidity at or below 15 percent and wind gusts of at 
  least 25 mph in the mountains, or 30 mph in the Snake Plain.

* Thunderstorm coverage of 25 percent, without specific rainfall 
  criteria.

* Other high impact events deemed critical by the National 
  Weather Service and area fire management agencies.

&&

$$

459 
WWUS85 KPIH 110251
RFWPIH

URGENT - FIRE WEATHER MESSAGE
National Weather Service Pocatello ID
851 PM MDT Mon Sep 10 2018


IDZ422-475-476-110400-
/O.EXP.KPIH.FW.W.0014.000000T0000Z-180911T0300Z/
Sawtooth Range/Northern Sawtooth NF-
East Salmon River Mountains/Salmon NF-
Lemhi and Lost River Range/Challis NF-
851 PM MDT Mon Sep 10 2018

...RED FLAG WARNING WILL EXPIRE AT 9 PM MDT THIS EVENING FOR
GUSTY WINDS AND LOW RELATIVE HUMIDITY FOR FIRE WEATHER ZONES 422,
475 AND 476...

Winds have subsided and humidity values are beginning to increase.
Therefore the Red Flag Warning will be allowed to expire at 9 pm.

$$

Area Forecast Discussion
National Weather Service Pocatello ID
230 AM MDT Sun Sep 9 2018

.Short Term...Today through Monday night
Just a few passing high clouds are left over from a system that
has since pushed well east of the area. Sky will continue to clear
through the morning as dry westerly flow is established. The
downside to these west winds, however, is the advection of smoke
from northern CA wildfires. The bulk of this smoke should stay
confined to the southern Snake Plain and south but will do little
to inhibit temperatures from holding steadily above average.

The surface high centered south of us today will flop east Monday
as another weak disturbance streams through northern Idaho. This
will allow our winds to pick up again with the tightening pressure
gradient. This could ultimately set up some marginal Fire Weather
concerns, discussed further below.
TAX

.Long Term...Tuesday through Sunday
A bowling ball of low pressure will skirt down the Pacific
Northwest coastline early this week. While this system isn't
expected to maintain it's strength as it inches closer mid-week,
it will have some impact to our local forecast area. Primarily,
the lowering heights will serve to cap daily temperatures. Highs
should fall back towards averages Tuesday and then a few degrees
below averages by Weds and Thurs.

A mostly dry forecast has been maintained, but models continue to
hint at at least some light precipitation with ejecting waves
Weds or Thurs. Nudged the forecast toward a blend of the EC/GFS
which inserts slight chance PoPs across the central mountains, but
is more impactful to our neighbors to the north. Areas south and
east of I-84 and I-15 respectively appear to stay dry through the
next 7 days.
TAX

&&

.AVIATION...Except for some cirrus tonight, skies should be clear.
Dispersion modeling of the smoke issues indicates that by
09/1000Z smoke will not impact VSBY at KPIH, 09/1400Z at KDIJ,
091900Z at KIDA. However, smoke could be moving into KSUN around
09/1800Z. KBYI and KSUN should worsen during the afternoon. Also,
KSUN probably the most affected. Assuming smoke will not totally
block out the sunshine, still expect the normal terrain-driven
wind, but maybe not as strong in magnitude. Messick

&&

.FIRE WEATHER...Except for a weak low moving through Canada and
Montana on Tue night/Wed/Wed night, clouds and precipitation will be
hard to find. So the main forecast problem is the very low humidity
that will continue with widespread areas below 15% each afternoon,
and the potential for breezy to windy conditions creating a Red
Flag environment. The next time for a large area meeting the
criteria are in the high elevations of the Salmon-Challis NF and
the Caribou NF on Mon afternoon. The oncoming shift will have to
double-check the elevations and fuel criticality later today, so
will hold off on any sort of watch, but believe it is likely.
Cooling temperatures after Mon make any sort of critical fire
weather patterns tougher to achieve, mainly in the humidity
department. There is an extended period of upper level southwest
flow which generally is dry, and a low is meandering around the
west coast. The latest GFS run, all of a sudden, has quite a bit
of precipitation, while the ECMWF has been more stable with the
dry solution. Both guidance product suites have given up on the
closed low staying on the California coast after splitting from
the higher latitude jet stream. The GFS has the northern stream
farther south and that is why the precipitation in the extended
period is there. However, it is a new wrinkle and will be slow to
trust this solution. Messick

&&

.PIH WATCHES/WARNINGS/ADVISORIES...
None.
&&