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FNUS21 KWNS 241658
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1158 AM CDT FRI MAY 24 2013
VALID 241700Z - 251200Z
...CRITICAL FIRE WEATHER AREA FOR NRN AZ...PORTIONS OF NWRN/W-CNTRL
NM...PORTIONS OF SRN UT...SWRN CO...FAR SRN NV...A SMALL PART OF
SERN CA...
...NRN AZ...PORTIONS OF NWRN/W-CNTRL NM...PORTIONS OF SRN UT...SWRN
CO...FAR SRN NV...A SMALL PART OF SERN CA...
NO CHANGES HAVE BEEN MADE TO THE AREAL DELINEATION OF CRITICAL FIRE
WEATHER CONDITIONS. MODESTLY STRONG SWLY FLOW ALOFT CONTINUES ACROSS
THE AREA IN CONJUNCTION WITH AN ENHANCED MID-LEVEL HEIGHT GRADIENT
BETWEEN A WRN-CONUS TROUGH AND A CNTRL-CONUS RIDGE. THE 12Z
FLAGSTAFF RAOB AND RECENT VWP DATA INDICATE AROUND 30-40 MPH OF FLOW
AOA 3 KFT AGL...AND THIS WILL SUPPORT THE POTENTIAL FOR STRONG SFC
WINDS AS VERTICAL MIXING DIURNALLY STRENGTHENS.
THE LATEST MODEL GUIDANCE INDICATES A POTENTIAL FOR SUBTLE WEAKENING
OF 700-MB FLOW DURING THE DAY...WHICH COULD CORRESPOND TO SFC WIND
SPEEDS BECOMING ONLY MARGINALLY STRONG DURING THE AFTERNOON.
REGARDLESS...SLY TO SWLY SFC WINDS AROUND 20 MPH WITH LOCALLY HIGHER
GUSTS ARE EXPECTED TO COMBINE WITH RH VALUES FROM THE UPPER SINGLE
DIGITS TO THE MIDDLE TEENS AMIDST BELOW-NORMAL PRECIPITATION DURING
THE PAST FEW MONTHS TO SUPPORT LOW-END CRITICAL FIRE WEATHER
CONDITIONS. IN FACT...WIND SPEEDS MAY BE A LITTLE WEAKER THAN THOSE
YESTERDAY. REGARDLESS...WITH THE LOW-END CRITICAL FIRE WEATHER
THREAT STILL ANTICIPATED...THE CRITICAL AREA HAS BEEN MAINTAINED
FOLLOWING COORDINATION WITH THE FLAGSTAFF WEATHER FORECAST OFFICE.
...SRN AZ...
TO THE SOUTH OF THE CRITICAL AREA...ELEVATED FIRE WEATHER CONDITIONS
ARE EXPECTED AS RH VALUES BECOME CRITICALLY LOW. HOWEVER...ANY MORE
THAN SPOTTY AND/OR BRIEF INSTANCES OF CRITICALLY STRONG SUSTAINED
WIND SPEEDS ARE NOT EXPECTED IN THE ABSENCE OF STRONGER
LOW/MID-LEVEL FLOW.
...MOUNTAINS OF CNTRL NM AND THE IMMEDIATELY ADJACENT HIGH PLAINS...
OVER THE WRN FRINGES OF RICHER LOWER/MIDDLE-TROPOSPHERIC
MOISTURE...ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED
TO DEVELOP THIS AFTERNOON ACROSS THE CNTRL NM MOUNTAINS AS
OROGRAPHIC CIRCULATIONS OFFER LOW-LEVEL ASCENT. HIGH-BASED
CONVECTIVE INITIATION IS FORECAST TO OCCUR IN AN ENVIRONMENT
CHARACTERIZED BY PW VALUES BETWEEN 0.50 AND 0.75 INCH PER GPS DATA
SUPPORTING ISOLATED TO WIDELY SCATTERED DRY THUNDERSTORMS...AS 20-35
MPH OF MID-LEVEL FLOW YIELD MODEST STORM MOTIONS FROM THE MOUNTAINS
TO THE IMMEDIATELY ADJACENT HIGH PLAINS. IN THE ABSENCE OF STRONGER
DEEP FORCING FOR ASCENT...ANY DRY THUNDERSTORM COVERAGE SHOULD BE
ISOLATED TO WIDELY SCATTERED. REGARDLESS...DRY/VERY DRY FUELS MAY
PROMOTE LIGHTNING-INDUCED IGNITIONS AS SFC RH VALUES FALL TO AROUND
15-20 PERCENT AMIDST DRY/VERY DRY FUELS...AND THERMODYNAMIC PROFILES
BECOME CHARACTERIZED BY DEEP INVERTED-VEE STRUCTURES.
AS THUNDERSTORMS ADVANCE OVER THE LOWER ELEVATIONS OF ERN NM AND
ENCOUNTER RICHER LOW-LEVEL MOISTURE/GREATER
BUOYANCY...EVOLVING/MERGING COLD POOLS MAY GIVE WAY TO SOMEWHAT
HIGHER THUNDERSTORM COVERAGE. HOWEVER...THIS ACTIVITY WILL ENCOUNTER
INCREASINGLY HIGHER PW/HIGHER SFC RH...WITH THUNDERSTORM MODES
TRANSITIONING TO MIXED WET/DRY. REGARDLESS...LIGHTNING STRIKES
OUTSIDE OF RAIN CORES COULD YIELD IGNITIONS AMIDST ONGOING DROUGHT
CONDITIONS.
WITH THE COVERAGE OF PURELY DRY THUNDERSTORMS NOT EXPECTED TO EXCEED
WIDELY SCATTERED...A CRITICAL AREA HAS NOT BEEN INCLUDED AT THIS
TIME.
..COHEN.. 05/24/2013
.PREV DISCUSSION... /ISSUED 0404 AM CDT FRI MAY 24 2013/
...SYNOPSIS...
A POTENT SHORTWAVE TROUGH...ROTATING THROUGH THE FLOW SURROUNDING
THE PACIFIC NORTHWEST UPPER LOW...WILL CONTINUE TO LIFT
NORTH/NORTHEAST ACROSS THE NORTHERN ROCKIES TODAY. AHEAD OF THIS
TROUGH...SHORTWAVE RIDING IS EXPECTED TO CONTINUE TO BUILD ACROSS
THE CENTRAL US...WHICH IN TURN SHOULD AID THE DEEPENING OF THE
EASTERN CONUS TROUGH.
ACROSS THE SOUTHWESTERN STATES...A ZONE OF ENHANCED WEST/SOUTHWEST
FLOW SHOULD PERSIST THROUGH MUCH OF TODAY. HERE...DIURNAL HEATING
SHOULD RESULT IN DEEP MIXING OF AN ALREADY DRY BOUNDARY
LAYER...RESULTING IN DAYTIME HIGH TEMPERATURES WARMING INTO THE 80S
AND 90S COUPLED WITH SFC DEWPOINTS FALLING INTO THE SINGLE DIGITS TO
LOW TEENS /YIELDING RELATIVE HUMIDITY VALUES IN THE SINGLE DIGITS TO
LOW TEENS FOR MUCH OF THE AFTERNOON/. FURTHERMORE GIVEN THE STRONG
FLOW ALOFT AND THE DEEP MIXING...STRONG/GUSTY WINDS ARE EXPECTED TO
MIX DOWN TO THE SFC RESULTING IN A PROLONGED PERIOD OF CONDITIONS
EXCEEDING THE CRITICAL THRESHOLD.
...SOUTHERN ARIZONA...
TO THE SOUTH OF THE CRITICAL AREA...MID-LEVEL FLOW IS EXPECTED TO
REMAIN WEAKER THAN FARTHER NORTH. THUS...EVEN THROUGH SFC RH VALUES
WILL EXCEED CRITICAL THRESHOLDS...DIURNAL MIXING WILL ONLY RESULT IN
SUB-CRITICAL THRESHOLD SFC WINDS /15-20 MPH/.
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
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FNUS22 KWNS 241827
DAY 2 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0127 PM CDT FRI MAY 24 2013
VALID 251200Z - 261200Z
...CRITICAL FIRE WEATHER AREA FOR FAR SRN NV...EXTREME SRN UT...NRN
AZ...PORTIONS OF NWRN/W-CNTRL NM...SWRN CO...
...FAR SRN NV...EXTREME SRN UT...NRN AZ...PORTIONS OF NWRN/W-CNTRL
NM...SWRN CO...
NO CHANGES HAVE BEEN MADE TO THE ONGOING FORECAST. THE LATEST
MULTI-MODEL CONSENSUS INDICATES THAT CRITICAL FIRE WEATHER
CONDITIONS ARE ANTICIPATED AS AFTERNOON RH VALUES OF 8-14 PERCENT
COMBINE WITH SSWLY/SWLY SFC WINDS AROUND 20-25 MPH AND GUSTS
REACHING AROUND 30 MPH.
...SRN AZ...
NO CHANGES HAVE BEEN MADE TO THE ONGOING FORECAST. ELEVATED FIRE
WEATHER CONDITIONS ARE EXPECTED AS RH VALUES BECOME CRITICALLY LOW.
HOWEVER...IN THE ABSENCE OF STRONGER LOW/MID-LEVEL FLOW...CRITICALLY
STRONG SUSTAINED WIND SPEEDS ARE NOT EXPECTED TO OCCUR ON ANY MORE
THAN A BRIEF/SPOTTY BASIS. AS SUCH...CRITICAL DESIGNATION IS NOT
NEEDED.
...MOUNTAINS OF CNTRL NM AND THE IMMEDIATELY ADJACENT HIGH PLAINS...
ISOLATED TO WIDELY SCATTERED THUNDERSTORMS ARE EXPECTED TO DEVELOP
DURING THE AFTERNOON HOURS OVER THE CNTRL NM MOUNTAINS AS OROGRAPHIC
ASCENT STRENGTHENS. PW VALUES FROM 0.50 TO 0.75 INCH AND DEEP
INVERTED-VEE THERMODYNAMIC PROFILES PER FORECAST SOUNDINGS SHOULD
SUPPORT A DRY-THUNDERSTORM MODE. AND...WITH DRY/VERY DRY
FUELS...LIGHTNING-INDUCED IGNITIONS COULD OCCUR AS SFC RH VALUES
FALL TO AROUND 15-20 PERCENT AMIDST DRY/VERY DRY FUELS.
AS THUNDERSTORMS ADVANCE OVER THE LOWER ELEVATIONS OF ERN NM AND
ENCOUNTER RICHER LOW-LEVEL MOISTURE/GREATER BUOYANCY...
EVOLVING/MERGING COLD POOLS MAY YIELD SOMEWHAT HIGHER THUNDERSTORM
COVERAGE. HOWEVER...THIS ACTIVITY WILL ENCOUNTER INCREASINGLY HIGHER
PW/HIGHER SFC RH...WITH THE THUNDERSTORM MODE TRANSITIONING TO MIXED
WET/DRY. REGARDLESS...LIGHTNING STRIKES OUTSIDE OF RAIN CORES COULD
YIELD IGNITIONS AMIDST ONGOING DROUGHT CONDITIONS.
SINCE THE COVERAGE OF PURELY DRY THUNDERSTORMS IS NOT EXPECTED TO
EXCEED WIDELY SCATTERED...A DRY-THUNDERSTORM CRITICAL AREA HAS NOT
BEEN INCLUDED AT THIS TIME.
..COHEN.. 05/24/2013
.PREV DISCUSSION... /ISSUED 0458 AM CDT FRI MAY 24 2013/
...SYNOPSIS...
AN UPPER LOW IS FORECAST TO REMAIN NEARLY STATIONARY ACROSS THE
PACIFIC NORTHWEST AS A SERIES OF SUBTLE SHORTWAVE TROUGHS ROTATES
THROUGH THE LARGER SCALE FLOW AROUND THIS LOW ON SATURDAY.
ACROSS THE SOUTHWESTERN STATES...A ZONE OF ENHANCED WEST/SOUTHWEST
FLOW IS EXPECTED TO PERSIST THROUGH SATURDAY. HERE /ONCE AGAIN/
STRONG INSOLATION SHOULD RESULT IN DEEP MIXING OF A PERSISTENTLY DRY
BOUNDARY LAYER...RESULTING IN WARM DAYTIME TEMPERATURES /80S AND
90S/ AND LOW AND RELATIVE HUMIDITY VALUES IN THE SINGLE DIGITS TO
LOW TEENS FOR MUCH OF THE DAY. ADDITIONALLY...GIVEN THE RELATIVELY
STRONG FLOW ALOFT AND THE FORECAST DEEP MIXING...STRONG/GUSTY SFC
WINDS /20-25 MPH WITH GUSTS TO 30/ SHOULD DEVELOP...WARRANTING THE
CRITICAL RISK.
...SOUTHERN ARIZONA...
CONDITIONS HERE APPEAR TO BE SIMILAR TO THOSE FARTHER NORTH IN THE
CRITICAL AREA. ONE MITIGATING FACTOR IN THIS AREA IS THAT IT THIS
AREA IS A LITTLE MORE REMOVED FROM THE STRONG MID-LEVEL FLOW AND
THUS AFTERNOON MIXING SHOULD RESULT IN SLIGHTLY WEAKER SFC WINDS
NEARING...BUT NOT ACHIEVING...CRITICAL THRESHOLDS FOR THE REQUISITE
DURATION /3 HRS/.
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
