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SPC Wildfire Outlook for April 1, 2015

Fire Outlook

Day 1 SPC Wild Fire Monitored Area Discussion

213 
FNUS21 KWNS 311617
FWDDY1

DAY 1 FIRE WEATHER OUTLOOK  
NWS STORM PREDICTION CENTER NORMAN OK
1116 AM CDT TUE MAR 31 2015

VALID 311700Z - 011200Z

...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF S-CNTRL MT...
...CRITICAL FIRE WEATHER AREA FOR PORTIONS OF CNTRL VA...

...PIEDMONT REGION...
14-15Z SFC OBS ACROSS THE AREA INDICATE RH VALUES ARE ALREADY
FALLING INTO THE UPPER 20S ACROSS PORTIONS OF CNTRL VA THIS MORNING.
WITH FURTHER DIURNAL MIXING THROUGH THIS AFTERNOON...SWLY FLOW AHEAD
OF AN APPROACHING FRONT WILL REACH 15-25 MPH /WITH HIGHER
GUSTS/...WHILE RH VALUES CONTINUE TO DECREASE. THE BEST OVERLAP OF
STRONGER FLOW AND LOW RH VALUES /I.E. LESS THAN 25 PERCENT/ IS
LIKELY TO OCCUR ACROSS PORTIONS OF THE BLUE RIDGE MTNS AND
SHENANDOAH VALLEY. AS SUCH...A CRITICAL DELINEATION HAS BEEN
INTRODUCED FOR THIS AREA. OTHERWISE...NO SIGNIFICANT CHANGES WERE
MADE TO THE ELEVATED DELINEATION...EXCEPT FOR REMOVING MOST OF MD TO
ACCOUNT FOR RELATIVELY UNRECEPTIVE FUELS /UPON COLLABORATION WITH
LWX/.

...NRN/CNTRL HIGH PLAINS...
A CRITICAL DELINEATION HAS BEEN ADDED FOR PORTIONS OF S-CNTRL
MT...AS MORNING GUIDANCE SUGGESTS A CORRIDOR OF ENHANCED W/SWLY
LOWER-TROPOSPHERIC FLOW WILL DEVELOP BEHIND THE PASSAGE OF THE SFC
TROUGH. WITH DOWNSLOPE FLOW/DEEP DIURNAL MIXING ESTABLISHED...WINDS
WILL INCREASE TO 20-30 MPH /WITH HIGHER GUSTS/ WHILE RH VALUES WILL
FALL BELOW 20 PERCENT. ELSEWHERE...NO MAJOR ALTERATIONS WERE MADE TO
THE ELEVATED AREA...EXCEPT FOR REMOVING MOST OF CO AS WINDS WILL
LIKELY BE TOO LIGHT...AND ADDING MORE OF CNTRL NE WHERE WINDS WILL
APPROACH 15-20 MPH THIS AFTERNOON.

..PICCA.. 03/31/2015

.PREV DISCUSSION... /ISSUED 0353 AM CDT TUE MAR 31 2015/

...SYNOPSIS...
PROGRESSIVE TROUGH-RIDGE-TROUGH PATTERN IS EXPECTED WITHIN THE
NRN-STREAM. WRN SHORTWAVE TROUGH WILL MOVE THROUGH THE PACIFIC NW
AND NRN ROCKIES WHILE THE ERN SHORTWAVE TROUGH MOVES QUICKLY FROM
THE UPPER MIDWEST/UPPER GREAT LAKES SEWD THROUGH THE OH VALLEY AND
OFF THE NRN MID-ATLANTIC COAST. UPPER RIDGE BETWEEN THESE TWO
FEATURES WILL MOVE ACROSS THE PLAINS. SRN-STREAM SHORTWAVE TROUGH
WILL WEAKEN AS IT MOVES FROM THE CNTRL BAJA PENINSULA EWD ACROSS
CNTRL MEXICO. AT THE SURFACE...PRESSURE IS EXPECTED TO DROP ACROSS
MUCH OF THE PACIFIC NW AND NRN HIGH PLAINS IN RESPONSE TO THE
SHORTWAVE TROUGH AND AN ATTENDANT COLD FRONT. FARTHER E...LOW
ASSOCIATED WITH THE ERN SHORTWAVE WILL MOVE OFF THE MID-ATLANTIC
AROUND 00Z/WED WHILE A RIDGE MOVES FROM THE PLAINS INTO THE MS AND
TN VALLEYS.  

...NRN HIGH PLAINS...
UPPER RIDGE AND ASSOCIATED THERMAL TROUGH MOVING ACROSS THE REGION
DURING THE DAY WILL HELP MAINTAIN WARM AND DRY CONDITIONS. THESE
WARM AND DRY CONDITIONS COMBINED WITH EXPECTED LEE TROUGHING AND
DOWNSLOPE EFFECTS WILL RESULT IN NEAR-RECORD HIGHS THROUGHOUT THE
REGION /HIGH TEMPERATURES IN THE UPPER 70S AND LOW 80S/ WITH MIN RH
VALUES BELOW 15 PERCENT LIKELY. IN AREAS WHERE DOWNSLOPE EFFECTS ARE
MAXIMIZED -- I.E. DOWNWIND OF THE ABSAROKAS...LARAMIES..AND BIGHORNS
-- SINGLE DIGIT RH VALUES ARE POSSIBLE. MODEL GUIDANCE REMAINS
CONSISTENT IN SUGGESTING MUCH OF THE REGION WILL BE WITHIN THE
SURFACE TROUGH AXIS WITH WINDS RELATIVELY MODEST AS A RESULT. WHILE
ISOLATED LOCATIONS -- PARTICULARLY AROUND BIL -- MAY SEE WINDS
INCREASE ABOVE 20 MPH...WINDS ARE GENERALLY EXPECTED TO REMAIN
AROUND 10-15 MPH. THESE METEOROLOGICAL CONDITIONS IN CONCERT WITH
DRY FUELS WILL SUPPORT AN ELEVATED TO LOCALLY CRITICAL FIRE WEATHER
THREAT.

...PIEDMONT...
MODEL GUIDANCE VARIES SIGNIFICANTLY REGARDING LOW-LEVEL MOISTURE
WITH RESULTANT DISPARITY IN MIN RH VALUES. THE RAP
CHARACTERISTICALLY SUGGESTS THE LOWEST VALUES WITH MIN RH BELOW 20
PERCENT THROUGHOUT THE MAJORITY OF THE PIEDMONT. NEITHER THE NAM NOR
THE GFS ARE THAT AGGRESSIVE WITH MIN RH VALUES WITH VALUES PROGGED
TO REMAIN ABOVE 30 PERCENT. SREF GUIDANCE SHOWS A SIMILAR FORECAST
WITH ALL MEMBERS KEEPING MUCH OF THE REGION AT OR ABOVE 30 PERCENT.
A SLIGHTLY DRIER FORECAST IS FAVORED WITH MIN RH THROUGHOUT THE AREA
EXPECTED BETWEEN 25 TO 30 PERCENT. SWLY WINDS AHEAD OF THE FRONT
AROUND 20 MPH ARE LIKELY WITH THE RESULTANT COMBINATION OF DRY
FUELS...GUSTY WINDS...AND LOW RH VALUES FAVORING AN ELEVATED TO
LOCALLY CRITICAL FIRE WEATHER THREAT. AN UPGRADE TO CRITICAL MAY BE
NEEDED DURING THE DAY IF CONFIDENCE IN RH VALUES BELOW 25 PERCENT
INCREASES. 

...GREAT BASIN...
WINDS THROUGHOUT MUCH OF THE GREAT BASIN ARE EXPECTED TO APPROACH
20-25 MPH AS THE SURFACE PRESSURE GRADIENT INCREASES AHEAD OF THE
COLD FRONT. HIGH TEMPERATURES IN THE LOWER ELEVATIONS ARE EXPECTED
TO BE IN THE 70S /15 TO 20 DEGREES ABOVE AVERAGE/ WITH MANY AREAS
EXPERIENCING RH VALUES LESS THAN 15 PERCENT. DESPITE THESE CRITICAL
METEOROLOGICAL CONDITIONS...UNRECEPTIVE FUELS WILL KEEP ANY FIRE
WEATHER THREAT LOW WITH ONLY LOCALLY ELEVATED CONDITIONS
ANTICIPATED.

...PLEASE SEE WWW.SPC.NOAA.GOV/FIRE FOR GRAPHIC PRODUCT...