FNUS21 KWNS 250906
FWDDY1
DAY 1 FIRE WEATHER OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0405 AM CDT SAT MAY 25 2013
VALID 251200Z - 261200Z
...CRITICAL FIRE WEATHER AREA FOR NORTHERN ARIZONA...NORTHWESTERN
NEW MEXICO...EXTREME SOUTHERN UTAH...AND EXTREME SOUTHEASTERN
NEVADA...
...SYNOPSIS...
ANOTHER IN A SERIES OF SHORTWAVE TROUGHS IS FORECAST TO ROTATE
THROUGH THE FLOW SURROUNDING THE LARGE...STATIONARY PACIFIC
NORTHWEST UPPER LOW. TO THE EAST OF THIS UPPER LOW...SHORTWAVE
RIDGING SHOULD PERSIST ACROSS THE CENTRAL UNITED STATES.
...NORTHERN ARIZONA...NORTHWESTERN NEW MEXICO...EXTREME SOUTHERN
UTAH...AND EXTREME SOUTHEASTERN NEVADA...
STRONG DIURNAL HEATING...COUPLED WITH A DRY ATMOSPHERE /PW VALUES AT
OR BELOW 0.25 INCHES/...WILL ONCE AGAIN RESULT IN RH VALUES DROPPING
INTO THE SINGLE DIGITS ACROSS MUCH OF THE AREA. MODEST LOW-TO-MID
LEVEL FLOW /AROUND 700 MB/ AND DEEPLY MIXED BOUNDARY LAYERS WILL
RESULT IN SURFACE WINDS NEAR OR SLIGHTLY ABOVE 20 MPH YIELDING AT
LEAST LOW-END CRITICAL FIRE WEATHER CONDITIONS. HOWEVER...GIVEN
MODEL/OBSERVATIONAL TRENDS OF DECREASING THE LOW-TO-MID LEVEL
FLOW...SURFACE WINDS MAY END UP BEING SLIGHTLY LESS THAN FORECAST.
IF OBSERVATIONS LATER TODAY SUPPORT THIS DECREASED SURFACE WIND
SCENARIO..THE CRITICAL RISK MAY NEED TO BE DOWNGRADED IN THE DAY 1
UPDATE.
...AREAS OF SOUTHERN ARIZONA AND SOUTHERN UTAH...SURROUNDING THE
CRITICAL AREA...
ELEVATED FIRE WEATHER CONDITIONS ARE EXPECTED IN THE AREAS
SURROUNDING THE CRITICAL RISK. RELATIVE HUMIDITY VALUES ARE ONCE
AGAIN EXPECTED TO BE CRITICALLY LOW DURING THE AFTERNOON
HOURS...WITH THE DRIEST CONDITIONS EXPECTED ACROSS SOUTHERN ARIZONA
/RH VALUES IN THE SINGLE DIGITS/...AND SLIGHTLY MORE MOIST
CONDITIONS ACROSS SOUTHERN UTAH /RH IN THE TEENS/. WIND SPEEDS ARE
EXPECTED TO FLIRT WITH EXCEEDING CRITICAL THRESHOLD /20 MPH/ AT
TIMES DURING THE AFTERNOON...WITH THE HIGHEST POTENTIAL FOR
EXCEEDING 20 MPH ACROSS SOUTHERN UTAH. HOWEVER...AT THIS TIME IS
APPEARS THAT JOINT OCCURRENCE OF CRITICALLY LOW RH AND CRITICALLY
HIGH WIND SPEEDS OCCURRING FOR THE REQUISITE 3 HRS APPEARS
SUFFICIENTLY LOW THAT A CRITICAL DELINEATION IS NOT WARRANTED.
...MOUNTAINS OF CENTRAL NEW MEXICO...
WIDELY SCATTERED AFTERNOON THUNDERSTORMS ARE EXPECTED TO DEVELOP IN
FAVORED OROGRAPHIC ASCENT AREAS. PW VALUES HERE ARE EXPECTED TO
REMAIN BELOW 0.75 INCHES. THIS...COUPLED WITH DEEP INVERTED-VEE
SOUNDINGS WILL TEND TO PREVENT MOST PRECIPITATION FROM REACHING THE
GROUND WITH ANY CONVECTION THAT DOES DEVELOP. GIVEN THE WIDELY
SCATTERED NATURE OF ANY CONVECTION...A CRITICAL IS NOT FELT TO BE
NECESSARY. SHOULD LATER FORECASTS INDICATE MORE CONVECTION THAN
CURRENTLY EXPECTED...A DRY THUNDERSTORM CRITICAL MAY BE NEEDED.
..MARSH.. 05/25/2013
...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...
