Alert archive / Oregon / Red Flag Warnings in 2017

Red Flag Warning 46, NWS Medford, OR

September 5, 2017Modoc County, Siskiyou County, California; 9 counties in Oregon

NWS Medford, OR issued this red flag warning at Sep 5, 2017, 2:07 PM PDT for Modoc County, Siskiyou County, California; 9 counties in Oregon. It took effect at Sep 5, 2017, 11:00 PM PDT. It was in force for 42 hr. 5 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Sep 5, 2017, 2:07 PM PDT (21:07 UTC)
In effect from
Sep 5, 2017, 11:00 PM PDT
Expired
Sep 7, 2017, 5:18 PM PDT
In force
42 hr
Issued by
NWS Medford, OR

Counties Modoc County, CA, Siskiyou County, CA, Coos County, OR, Curry County, OR, Douglas County, OR, Harney County, OR, Jackson County, OR, Josephine County, OR, Klamath County, OR, Lake County, OR, Lane County, OR

The radar

The Medford radar (KMAX), 76 km from the middle of the area, began a volume at 21:09 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

TimeReportWhereRemark
Sep 6, 2:10 PM PDTTSTM WND GST 231 S Adin, CASPOTTER REPORTED WINDS 17G23 MPH AND ESTIMATED JUST OVER PEA SIZED HAIL.
Sep 7, 1:42 PM PDTHAIL 0.881 Se Oakridge, ORPUBLIC REPORT NEAR DINKS MARKET JUST TO THE SE OF OAKRIDGE
Sep 7, 1:45 PM PDTHAIL 1.751 E Oakridge, ORHAIL REPORT RELAYED VIA EUGENE PUBLIC WORKS. ESTIMATED SIZE OF HAIL OBSERVED BY EMPLOYEE.
Sep 7, 2:40 PM PDTHAIL 0.75Mckenzie Bridge, ORPUBLIC REPORT VIA SOCIAL MEDIA
Sep 7, 2:45 PM PDTHAIL 0.75Blue River, ORA SOCIAL MEDIA REPORT AND TIME APPROXIMATED

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Medford/Jackson, OR (KMFR), launched 12:00Z, 9.1 hours before the alert went out and 55 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Medford/Jackson, OR at 12:00Z on 2017-09-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Medford/Jackson, OR at 12:00Z on 2017-09-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
2613 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

071 
WWUS86 KMFR 052107
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
207 PM PDT Tue Sep 5 2017

...Abundant lightning beginning tonight continuing into Thursday 
evening for Northern California and southern Oregon...

.A series of at least 3 low pressure impulses will move through 
the area from the southeast tonight through Thursday evening as 
low pressure moves northward along the California coast. Very dry 
vegetation combined with scattered lightning during this time 
period leads to significant concern for new fire starts. An 
initial shortwave impulse will move across northwestern California
and into Curry County tonight bringing a chance of thunderstorms 
there first. While there is a slight chance of thunderstorms 
elsewhere late tonight into early Wednesday, thunderstorm chances
increase for the remainder of the area late Wednesday morning 
through Thursday evening. Thunderstorm activity on Thursday could 
result in significant rainfall for some areas. 

CAZ280-ORZ618-619-062300-
/O.UPG.KMFR.FW.A.0038.170906T1400Z-170907T0600Z/
/O.NEW.KMFR.FW.W.0046.170906T0600Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
207 PM PDT Tue Sep 5 2017

...RED FLAG WARNING IN EFFECT FROM 11 PM THIS EVENING TO 11 PM
PDT THURSDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONE 280 IN CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN
OREGON...

The National Weather Service in Medford has issued a Red Flag
Warning, which is in effect from 11 PM this evening to 11 PM PDT
Thursday. This warning is an upgrade to the Fire Weather Watch 
that was previously in effect.

* Thunderstorms: The first in a series of low pressure impulses
  will move northwestward across northern California this evening
  bringing the possibility of isolated to scattered lightning
  overnight into Wednesday morning. Wednesday afternoon and
  evening the possibility of lightning is likely to shift more
  inland into fire weather zones 619 and 280, but Wednesday night
  into Thursday another low pressure impulse is expected to move
  through with another round of scattered lightning that could
  extend westward to the coast. 

* Affected area: Fire weather zone 280 in northern California, and
  fire weather zones 618 and 619 is southwestern Oregon.

* Wind: Gusty and erratic winds of 30 mph are possible from
  stronger thunderstorms tonight into Thursday morning. Storms
  Wednesday and Thursday afternoons and evenings could bring
  localized wind gusts as high as 40 mph.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr


Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions 
are either occurring now, or will shortly. Scattered thunderstorms
combined with dry fuels create conditions where many fire starts 
may occur in a short period of time.

&&

$$

CAZ281-282-284-285-ORZ615>617-620>625-062300-
/O.UPG.KMFR.FW.A.0038.170906T1400Z-170907T0600Z/
/O.NEW.KMFR.FW.W.0046.170906T1800Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
207 PM PDT Tue Sep 5 2017

...RED FLAG WARNING IN EFFECT FROM 11 AM WEDNESDAY TO 11 PM PDT
THURSDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONES 281, 282, 284, AND 285 IN NORTHERN CALIFORNIA AND FIRE
WEATHER ZONES 615, 616, 617, 620, 621, 622, 623, 624, AND 625 IN
OREGON...

The National Weather Service in Medford has issued a Red Flag
Warning, which is in effect from 11 AM Wednesday to 11 PM PDT
Thursday. This warning is an upgrade to the Fire Weather Watch
that as previously in effect.

* Thunderstorms: The first in a series of low pressure impulses
  will move northwestward across the area late tonight into
  Wednesday morning. While this will bring a slight possibility of
  thunderstorms to the area late tonight into Wednesday morning,
  Wednesday afternoon and evening the possibility of lightning
  will increase. Wednesday night into Thursday Thursday evening
  another low pressure impulse is expected to move through with
  another round of scattered lightning that could extend westward
  to the coast. Thunderstorms on Thursday could produce locally
  heavy rainfall.

* Affected area: Fire Weather Zones 281, 282, 284, and 285 in
  northern California, and fire weather zones 615, 616, 617, 620,
  621, 622, 623, 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 30 to 40 mph are possible from
  stronger thunderstorms.

* View the hazard area in detail at
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions 
are either occurring now, or will shortly. Lightning strikes with 
little or no precipitation combined with dry fuels create 
conditions where many fire starts may occur in a short period of 
time.

&&

$$

BTL

Visit us at www.weather.gov/medford
6 follow-up statements
349 
WWUS86 KMFR 061411
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
711 AM PDT Wed Sep 6 2017

...Abundant lightning expected today into Thursday evening for 
Northern California and southern Oregon...

CAZ280-ORZ618-619-071200-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
711 AM PDT Wed Sep 6 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THURSDAY 
FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONE 280 IN 
CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN OREGON...

* Thunderstorms: This afternoon and evening the possibility of
  lightning increases inland into fire weather zones 619 and 280,
  but tonight into Thursday another low pressure impulse is 
  expected to move through with another round of scattered 
  lightning that could extend westward to the coast.

* Affected area: Fire weather zone 280 in northern California,
  and fire weather zones 618 and 619 is southwestern Oregon. 

* Wind: Gusty and erratic winds of 30 mph are possible from
  stronger thunderstorms into Thursday morning. Storms today and
  Thursday afternoon and evening could bring localized wind gusts
  as high as 40 mph.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Scattered
thunderstorms combined with dry fuels create conditions where
many fire starts may occur in a short period of time.

&&

$$

CAZ281-282-284-285-ORZ615>617-620>625-071200-
/O.CON.KMFR.FW.W.0046.170906T1800Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
711 AM PDT Wed Sep 6 2017

...RED FLAG WARNING IN EFFECT FROM 11 AM TODAY TO 11 PM PDT 
THURSDAY FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER 
ZONES 281, 282, 284, AND 285 IN NORTHERN CALIFORNIA AND FIRE 
WEATHER ZONES 615, 616, 617, 620, 621, 622, 623, 624, AND 625 IN 
OREGON...

* Thunderstorms: The possibility for lightning will increase this
  afternoon and evening. Tonight into Thursday evening another 
  low pressure impulse is expected to move through with another 
  round of scattered lightning that could extend westward to the 
  coast. Thunderstorms on Thursday could produce locally heavy 
  rainfall.

* Affected area: Fire Weather Zones 281, 282, 284, and 285 in 
  northern California, and fire weather zones 615, 616, 617, 
  620, 621, 622, 623, 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 30 to 40 mph are possible 
  from stronger thunderstorms. 

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Lightning strikes with
little or no precipitation combined with dry fuels create
conditions where many fire starts may occur in a short period of
time.

&&

$$


Visit us at www.weather.gov/medford
111 
WWUS86 KMFR 062158
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
258 PM PDT Wed Sep 6 2017

...Abundant lightning expected today into Thursday evening for
Northern California and southern Oregon...

Multiple low pressure impulses will move north and northwestward
through the forecast are this afternoon through Thursday evening
resulting in showers and thunderstorms with scattered lightning.
Gusty outflow winds are expected with some of the storms. Small
hail and heavy rainfall are also possible, with the a threat of
flash flooding on and near recent burn scars in steep terrain.

CAZ280-ORZ618-619-071800-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
258 PM PDT Wed Sep 6 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THURSDAY
FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONE 280 IN
CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN OREGON...

* Thunderstorms: A low pressure impulse moving through this evening
  into tonight is likely to be followed by another one Thursday 
  morning. This will increase the possibility of isolated to 
  scattered lightning across this area spreading westward to the 
  coast. 

* Affected area: Fire weather zone 280 in northern California, 
  and fire weather zones 618 and 619 is southwestern Oregon.

* Wind: Gusty and erratic wind gust of 30 to 50 mph are possible
  from stronger thunderstorms. 

* Rainfall: Locally heavy rainfall is possible from these storms,
  which could result in flash flooding in and down drainage from 
  recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Scattered
thunderstorms combined with dry fuels create conditions where
many fire starts may occur in a short period of time.

&&

$$

CAZ281-282-284-285-ORZ615>617-620>625-071800-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
258 PM PDT Wed Sep 6 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THURSDAY
FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONES 281,
282, 284, AND 285 IN NORTHERN CALIFORNIA AND FIRE WEATHER ZONES
615, 616, 617, 620, 621, 622, 623, 624, AND 625 IN OREGON...

* Thunderstorms: The possibility for lightning will increase this
  afternoon and evening as a low pressure impulse moves through
  tonight. On Thursday another low pressure impulse is expected to
  move through with another round of scattered lightning that
  could extend westward to the coast. Thunderstorms on Thursday
  will produce locally heavy rainfall in some areas.

* Affected area: Fire Weather Zones 281, 282, 284, and 285 in 
  northern California, and fire weather zones 615, 616, 617, 
  620, 621, 622, 623, 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 35 to 55 mph are possible from
  stronger thunderstorms.

* Rainfall: Locally heavy rainfall is possible from these storms,
  which could result in flash flooding in and down drainage from 
  recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Lightning strikes with
little or no precipitation combined with dry fuels create
conditions where many fire starts may occur in a short period of
time.

&&

$$

BTL

Visit us at www.weather.gov/medford
814 
WWUS86 KMFR 071031
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
331 AM PDT Thu Sep 7 2017

...Abundant lightning expected through this evening for Northern 
California and southern Oregon...

Nearby low pressure will bring a strong impulse northward through
the forecast area today, resulting in showers and thunderstorms 
with scattered lightning. Gusty outflow winds are expected with 
some of the storms. Small hail and heavy rainfall are also 
possible, with the threat of flash flooding on and near recent 
burn scars in steep terrain.

CAZ280-ORZ618-619-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
331 AM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONE
280 IN CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN OREGON...

* Thunderstorms: Another round of scattered lightning is expected
  today. Storms are expected to move from to southeast to 
  northwest.

* Affected area: Fire weather zone 280 in northern California, 
  and fire weather zones 618 and 619 is southwestern Oregon.

* Wind: Gusty and erratic wind gust of 30 to 50 mph are 
  possible from stronger thunderstorms. 

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas. 

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Scattered
thunderstorms combined with dry fuels create conditions where
many fire starts may occur in a short period of time.

&&

$$

CAZ281-282-284-285-ORZ615>617-620>625-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
331 AM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONES 281, 282, 284, AND 285 IN NORTHERN CALIFORNIA AND FIRE
WEATHER ZONES 615, 616, 617, 620, 621, 622, 623, 624, AND 625 IN
OREGON...

* Thunderstorms: Another round of scattered lightning is expected
  today. Storms are expected to move from southeast to northwest.

* Affected area: Fire Weather Zones 281, 282, 284, and 285 in 
  northern California, and fire weather zones 615, 616, 617, 
  620, 621, 622, 623, 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 35 to 55 mph are possible 
  from stronger thunderstorms. 

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas. 

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Lightning strikes with
little or no precipitation combined with dry fuels create
conditions where many fire starts may occur in a short period of
time.

&&

$$


Visit us at www.weather.gov/medford
163 
WWUS86 KMFR 072128
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
228 PM PDT Thu Sep 7 2017

...Abundant lightning expected through this evening for Northern
California and southern Oregon...

Nearby low pressure is bringing a strong impulse northward 
through the forecast area this afternoon, resulting in showers 
and thunderstorms with scattered lightning. Gusty outflow winds 
are expected with these storms. Small hail and heavy rainfall are
also possible, with the threat of flash flooding on and near 
recent burn scars in steep terrain. Although these storms are
expected to be wet, there is still the concern for new fire 
starts outside of heavy rain cores as well as any holdover fires 
from yesterday's lightning. 

CAZ280-ORZ618-619-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
228 PM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONE
280 IN CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN OREGON...

* Thunderstorms: Another round of scattered lightning is expected
  today. Storm motion is from south to north. 

* Affected area: Fire Weather Zone 280 in northern California, and
  Fire Weather Zones 618 and 619 is southwestern Oregon.

* Wind: Gusty and erratic wind gusts of 30 to 50 mph are 
  possible from stronger thunderstorms.

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Scattered
thunderstorms combined with dry fuels create conditions where
many fire starts may occur in a short period of time.

&&

$$

CAZ281-282-284-285-ORZ615>617-620>625-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
228 PM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONES 281, 282, 284, AND 285 IN NORTHERN CALIFORNIA AND FIRE
WEATHER ZONES 615, 616, 617, 620, 621, 622, 623, 624, AND 625 IN
OREGON...

* Thunderstorms: Another round of scattered lightning is
  expected today. Storm motion is south to north. 

* Affected area: Fire Weather Zones 281, 282, 284, and 285 in
  northern California, and Fire Weather Zones 615, 616, 617, 620,
  621, 622, 623, 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 35 to 55 mph are possible 
  from stronger thunderstorms.

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Lightning strikes with
little or no precipitation combined with dry fuels create
conditions where many fire starts may occur in a short period of
time.

&&

$$


Visit us at www.weather.gov/medford
471 
WWUS86 KMFR 072251
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
351 PM PDT Thu Sep 7 2017

CAZ281-282-284-285-080000-
/O.CAN.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Central Siskiyou County Including Shasta Valley-Shasta-
Trinity National Forest in Siskiyou County-
Siskiyou County from the Cascade Mountains East and South to Mt
Shasta-Modoc County Except for the Surprise Valley-
351 PM PDT Thu Sep 7 2017

...RED FLAG WARNING IS CANCELLED FOR ABUNDANT LIGHTNING ON DRY
FUELS FOR FIRE WEATHER ZONES 281, 282, 284, AND 285 IN NORTHERN
CALIFORNIA...

The National Weather Service in Medford has cancelled the Red
Flag Warning. 

Isolated showers and a thunderstorm are possible through early
this evening, but the threat for abundant lightning has ended.

$$

CAZ280-ORZ618-619-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
351 PM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER ZONE
280 IN CALIFORNIA AND FIRE WEATHER ZONES 618 AND 619 IN OREGON...

* Thunderstorms: Storms with scattered lightning are still
  possible through this evening. Storm motion will be from south 
  to north. 

* Affected area: Fire Weather Zone 280 in northern California,
  and Fire Weather Zones 618 and 619 is southwestern Oregon. 

* Wind: Gusty and erratic wind gusts of 30 to 50 mph are 
  possible from stronger thunderstorms.

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Scattered
thunderstorms combined with dry fuels create conditions where
many fire starts may occur in a short period of time.

&&

$$

ORZ615>617-620>625-080600-
/O.CON.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
South Central Oregon Coast-Umpqua Basin-Umpqua National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
351 PM PDT Thu Sep 7 2017

...RED FLAG WARNING REMAINS IN EFFECT UNTIL 11 PM PDT THIS
EVENING FOR ABUNDANT LIGHTNING ON DRY FUELS FOR FIRE WEATHER
ZONES 615, 616, 617, 620, 621, 622, 623, northern and western 
parts of 624, AND 625 IN OREGON...

* Thunderstorms: Storms with scattered lightning are still
  possible through this evening. Storm motion will be from south
  to north. 
  
* Affected area: Fire Weather Zones 615, 616, 617, 620, 621, 622,
  623, northern and western parts of 624, and 625 in Oregon.

* Wind: Gusty and erratic winds of 35 to 55 mph are possible 
  from stronger thunderstorms.

* Rainfall: Locally heavy rainfall is possible from these 
  storms, which could result in flash flooding in and down 
  drainage from recently, severely burned steep terrain areas.

* View the hazard area in detail at 
  http://www.wrh.noaa.gov/map/?wfo=mfr

Precautionary/preparedness actions...

A Red Flag Warning means that critical fire weather conditions
are either occurring now, or will shortly. Lightning strikes with
little or no precipitation combined with dry fuels create
conditions where many fire starts may occur in a short period of
time.

&&

$$

MAS

Visit us at www.weather.gov/medford
703 
WWUS86 KMFR 080018
RFWMFR

URGENT - FIRE WEATHER MESSAGE
National Weather Service Medford OR
518 PM PDT Thu Sep 7 2017

CAZ280-ORZ615>625-080130-
/O.CAN.KMFR.FW.W.0046.000000T0000Z-170908T0600Z/
Western Klamath National Forest-South Central Oregon Coast-
Umpqua Basin-Umpqua National Forest-Southern Oregon Coast-
Western Rogue River-Siskiyou National Forest-
Western Rogue Basin including the Illinois Valley-
Siskiyou Mountains-Eastern Rogue Valley-Southern Oregon Cascades-
Klamath Basin and the Fremont-Winema National Forest-
South Central Oregon Desert including the BLM Land in Eastern
Lake and Western Harney Counties-
518 PM PDT Thu Sep 7 2017

...RED FLAG WARNING IS CANCELLED FOR ABUNDANT LIGHTNING ON DRY
FUELS FOR FIRE WEATHER ZONES 615, 616, 617, 620, 621, 622, 623,
NORTHERN AND WESTERN PARTS OF 624, AND 625 IN OREGON...

The National Weather Service in Medford has cancelled the Red
Flag Warning. 

Isolated showers and a thunderstorm are possible through early
this evening, but the threat for abundant lightning has ended.

$$

MAS

Visit us at www.weather.gov/medford

What forecasters said that day

The local office's own words before this red flag warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Medford, OR wrote its last area forecast discussion before this red flag warning went out at Sep 5, 9:08 AM PDT, 4 hours 59 minutes earlier.

Area forecast discussion, Sep 5, 9:08 AM PDT, 4 hours 59 minutes before
Area Forecast Discussion
National Weather Service Medford OR
908 AM PDT Tue Sep 5 2017

.DISCUSSION...
No updates have been made, thus far, this morning. We will be
assessing current headlines during the remainder of this morning
with the intent of updating all necessary headline products for
tomorrow and Thursday by noon today.

As for air quality, areas that are currently under heavy smoke are
generally expected to remain so with air quality remaining the
same or getting worse through at least Wednesday morning.
Thereafter, showers and thunderstorms could bring at least some
relief to some locations. BTL

&&

.AVIATION...05/12Z TAF CYCLE...Wildfire smoke will continue to limit
visibility to less than 2 miles across a large portion of the CWA
(including KMFR/KRBG/KLMT), but especially west of the Cascades
through this evening. Models suggest a push of smoke that could
reduce visibility even more later this afternoon in west side
valleys, and this is reflected in Medford's TAF.

Marine stratus will move south to north along the coast today and
should arrive near KOTH this evening as MVFR ceilings. Additionally,
there's a slight chance for thunderstorms mainly east of the
Cascades this afternoon to include northern California. -SK/DW

&&

.MARINE...Updated 230 AM PDT Tuesday 5 September 2017...Low pressure
well offshore will maintain light to moderate southerly winds
through Thursday night with westerly swell dominated seas. As the
low moves near the coast, showers are possible late Wednesday
through Friday. Winds will shift northerly Friday and should
increase into the weekend. A very long period northwest swell
component will move in Friday and build into the weekend. SK

&&

.FIRE WEATHER...Updated 200 PM PDT Monday 4 September 2017...Today
will feature the highest humidity west of the Cascades (in
Oregon...whereas western Siskiyou County could hold on to dry air)
since Thursday afternoon. Humidity should generally trend upwards by
5 to 20 percent today compared to yesterday west of the Cascades,
and this trend will spread to the Cascades and points east on
Wednesday. The low level northerly flow and upper ridging that
brought days of very low humidity day and night is shifting to deep
layer southerly flow as the upper ridge shifts eastward and
monsoonal moisture wraps north between the ridge and the offshore
upper low/remnants of Lidia. This will ensure this gradual trend of
higher humidity will continue through the week.

With the increase in moisture, our concern for very dry and windy
conditions diminishes and turns to thunderstorm potential.
Generally, the best chance for scattered thunderstorms exists when
we have a well-defined trigger, usually in the form of a nearby
upper low. So, as the aforementioned upper low gets closer to the
forecast area, our forecast thunderstorm coverage increases, and
impacts to area fires and potential for new fire starts becomes more
likely.

Today the low will remain about 500 miles to the southwest of the
forecast area, with only minor shortwaves affecting Southern Oregon
and Northern California. These shortwaves will interact with
sufficient moisture mainly east of the Cascades to generate a slight
chance of thunderstorms there. As the upper low moves northward and
nears the forecast area, Wednesday into Thursday morning (Thu
afternoon east of the Cascades) will feature the best chances for
scattered thunderstorms and significant impacts to the forecast area
in terms of new fire starts, outflow winds that could impact active
fires and fire crews, and the potential for rainfall over fires and
even the potential for reduction of smoke in some areas. In this
pattern with deep southerly flow and an approaching upper low,
nighttime thunderstorms are always a threat, and we have included
the chance for nighttime/morning convection early Wednesday and
again Wednesday night/Thursday morning.

Precipitable water values increase sharply late today and remain
high through Thursday, so wetting rains will be possible with
thunderstorms. Latest data suggests Thursday will be the best chance
for significant rainfall as steering flow decreases to around 10kt
from the Cascades west and precipitable water values peak near 1.4in
per the GFS20. We are not forecasting thunderstorms along the
Cascades and westward on Thursday because of the expected thick
cloud cover that should reduce instability, but the ingredients are
there for some heavy rainshowers. East of the Cascades there remains
a good chance of thunderstorms Thursday. Steering flow is stronger
today and Wednesday, and this means less chance for storms lingering
and dumping heavy rain one spot. And I must point out that even
though we expect rain with some of these storms, plenty of lightning
is expected outside of the storm cores, and this will land on very
dry fuels that are receptive to new fire starts. Thus, we have a
Fire Weather Watch out for abundant lightning on dry fuels for most
of the forecast area Wednesday morning through Wednesday evening.

The GEFS ensemble suggests a return to warm and dry conditions
(though with moderate amount of uncertainty and not to the extent of
the recent hot/dry weather) late this weekend into early next week.
SK

&&

.PREV DISCUSSION... /Issued 530 AM PDT Tue Sep 5 2017/

Updated aviation and marine discussions.

DISCUSSION...05/00Z NAM/GFS/EC in.

The northern hemispheric projection shows a wave number of five
around the globe...which supports a progressive pattern. That will
be the case around here...but it will be a very slow progression.

A strong long wave ridge over the western US will drift slowly
east into Friday. An offshore long wave trough will do the same
while it goes through several weakening/strengthening cycles,
ingesting and ejecting transient short waves.

None of those short waves will be a factor in the local weather,
but another low...the remnants of tropical cyclone Lidia...will
move into the weather picture. At this time it is spinning off
southern California, but it will move slowly north, moving into
Northern California Wednesday.

Weak short waves rotating around this upper low have and will
continue to move through the area, but the development of
convection has and will be greatly inhibited by the smoke from
over 100 wildfires that continues to envelope the area. Some
thunderstorms moved into that smoke today and dissipated quickly.

The smoke is the wild card here that greatly increases the
uncertainty of the convection forecast. So much will depend on
where the smoke is and how thick the layer is, because that
determines the degree of surface heating. Observed temperatures
have been running well below guidance due to the smoke cover.

The other factor, upper level support due to short waves moving
through the area, is an easier forecast. As the remnants of the
storm move closer to the area, the associated short waves will be
stronger and more upper level moisture will be advected into the
area. PWs over the area today were 0.50 to around 1.00 inches. The
moister areas likely would have had some convection Monday in an
environment with much less smoke. On Tuesday afternoon, the models
are showing 0.75 to 1.00 inches with the greatest increases on the
east side. Given that there is generally less smoke over there,
the slight chance in the current forecast looks good. Not so sure
about the slight chances over the west side though and will likely
reduce those.

Wednesday is a different story though. Not only are the short
waves stronger, PWs jump up to 1.00 to 1.50 inches or so and that
is pretty rich in terms of moisture. The current forecast of a
chance of thunderstorms over just about all of the CWA looks good
at this time.

The low will continue north and will be just offshore the Oregon
coast Thursday. PWs will still be in the 1.00 to 1.50 inch range,
but by this time temperatures will be cooler, smoke or no smoke,
and this will lessen the surface support for convection.

Extended discussion from the Monday afternoon AFD...Friday through
Sunday. The upper level trough near the Pacific Northwest coast
will gradually push inland late Friday. This will result in
temperatures cooling to near normal values along with a chance
for showers from the Cascades west and a chance for showers and
thunderstorms for areas east of the Cascades. This trough passage
inland may also bring increased mixing and areas with improving
smoke conditions. Saturday into Sunday, a flat ridge will
rebuild over the region. As a result expect warming conditions
once again. This pattern would also favor increased smoke in
western valleys. -Schaaf/CC

&&

.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Fire Weather Watch from Wednesday morning through Wednesday
     evening for ORZ615>625.

CA...Fire Weather Watch from Wednesday morning through Wednesday
     evening for CAZ280>282-284-285.
     Dense Smoke Advisory until noon PDT today for CAZ080.

Pacific Coastal Waters...None.

BTL/JRS/NSK

Nearby

Red Flag Warnings in Oregon, 2017Red Flag Warnings in California, 2017Every red flag warning in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.